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  • 251.
    Hedström, Erik M
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Svensson, Olle
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Bergström, Ulrica
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Michno, Piotr
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Epidemiology of fractures in children and adolescents: Increased incidence over the past decade: a population-based study from northrn Sweden2010In: Acta Orthopaedica, ISSN 1745-3674, E-ISSN 1745-3682, Vol. 81, no 1, p. 148-153Article in journal (Refereed)
    Abstract [en]

    Background and purpose Fractures are most common in youth and in the elderly, with differences in incidence over time and between regions. We present the fracture pattern in a population of youths <= 19 years of age, who were seen at Umeå University Hospital, Sweden. Material and methods All injuries seen at the hospital have been recorded in a database since 1993. The data include variables such as age, sex, date, type of injury, mechanism of injury, and treatment. For the period 1993-2007, there were 10,203 injury events that had resulted in at least 1 fracture. Results The incidence for the whole period was 201/10<sup>4</sup> person years. The incidence increased by 13% during the period 1998-2007, when we were able to control for registration errors. The most common fracture site was the distal forearm. The most common type of injury mechanism was falling. The peak incidence occurred at 11-12 years in girls and at 13-14 years in boys, with a male-to-female incidence ratio of 1.5. We found variations in mechanisms and activities at injury with age, and over time. Interpretation Fractures are caused by a combination of intrinsic and extrinsic factors that vary with age. We believe the increase in incidence is partly explained by changes in children's activity patterns over time. Further research may help to identify preventive measures to reduce the number of fractures, in particular those involving hospital care, surgical treatment, and-most importantly-long-term impairment.

  • 252. Hellspong, Gustaf
    et al.
    Gunnarsson, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Dahlstrand, Ursula
    Sandblom, Gabriel
    Diabetes as a risk factor in patients undergoing groin hernia surgery2017In: Langenbeck's archives of surgery (Print), ISSN 1435-2443, E-ISSN 1435-2451, Vol. 402, no 2, p. 219-225Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Diabetes is a known risk factor for early postoperative complications. Even so, the incidence of acute postoperative complications following routine hernia surgery is seldom described, and the risk for reoperation for recurrence has hardly been studied. Our aim was to explore if diabetes is a significant risk factor for complications after inguinal hernia surgery.

    METHODS: All inguinal hernia repairs registered in the Swedish Hernia Register between 2002 and 2011 were identified. Information on comorbidity and postoperative complications was obtained through cross-referencing with the National Patient Register at the National Board of Health and Welfare. Complicated diabetes was defined as diabetes with secondary manifestations (corresponding to aDCSI >0). The hazards for postoperative complications and reoperation for recurrence after the index hernia operation were calculated.

    RESULTS: Altogether 162,713 inguinal hernia repairs on 143,041 patients were registered. Of these, the number of patients with diabetes was 4816 (3.4 %), including 1123 (0.8 %) patients with complicated diabetes (aDCSI > 0). A significantly increased risk for postoperative complications was observed up to 30 days after hernia surgery when adjusted for gender, age, BMI, history of liver disease, kidney disease or HIV/AIDS, type of hernia and surgical method (odds ratio 1.35, 95 % confidence interval 1.14-1.60). No significantly increased risk for reoperation up until December 31, 2011, was observed in either patient group.

    CONCLUSION: Diabetes seems to increase the risk for postoperative complications within 30 days of inguinal hernia surgery, especially for complicated diabetes. Diabetes does not seem to increase the long-term risk for reoperation for recurrence.

  • 253.
    Hellström, Martin
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Hellström, Sten
    Department of Audiology and Neurotology, Karolinska University Hospital, Stockholm, Sweden.
    Engström-Laurent, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Bertheim, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    The structure of the basement membrane zone differs between keloids, hypertrophic scars and normal skin: A possible background to an impaired function2014In: Journal of Plastic, Reconstructive & Aesthetic Surgery, ISSN 1748-6815, E-ISSN 1532-1959, Vol. 67, no 11, p. 1564-1572Article in journal (Refereed)
    Abstract [en]

    Scar tissues were collected from patients with keloids, hypertrophic scars and mature scars. Normal skin was obtained from healthy individuals. Clinical attributes were used to select which tissue to obtain but the distribution of the specific hyaluronan (HA) staining was then used for the definite classification of the various scar types. Light microscopic and ultrastructural analyses were performed with an HA-binding probe, antibodies for collagen I and III and staining for mast cells. Ultrastructural studies of keloids revealed an altered collagen structure in the dermal layers, with an abundance of collagen fibres of similar diameter in both the reticular dermis (RD) and the papillary dermis (PD) compared to normal skin. Furthermore, the keloids displayed epidermal changes, which involved the basement membrane (BM), with fewer hemidesmosomes and an altered shape of desmosomes in the entire enlarged spinous layer. The frequency of mast cells found in keloids was lower than in other scar tissues and normal skin. These alterations in epidermis could influence the hydrodynamic and cell regulatory properties of the wounded skin with impaired function and insufficient regulative capacity to hinder the ever-growing collagen tissue that is characteristic for keloids. (C) 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  • 254. Hemberg, A
    et al.
    Nordin, Pär
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Holmberg, H
    Tobacco use as a risk factor for groin hernia repair2015In: lSI World Conference on Abdominal Wall Hernia Surgery, april 25, 2015., 2015, Vol. 19, p. S278-S278Conference paper (Refereed)
    Abstract [en]

    The pathogenesis and etiology of groin hernias are not fully understood. Some risk factors are unknown and some are debated. Tobacco has been speculated as a possible risk factor for groin hernias. Some studies have not showed any connection, whereas other has showed that smokers have primary hernias at a younger age and that recurrences of hernias are more common among smokers. There have also been several studies showing a connection between smoking and changes in collagen metabolism. Present study evaluates the connection between groin hernia repair and tobacco use.

  • 255.
    Hemmingsson, Oskar
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    ASNA1 and cisplatin resistance: studies in C. elegans and in human tumor cells2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Platinum based chemotherapy is widely used to treat cancer. Cisplatin (diamminedichloroplatinum) combination treatments provide cure for metastatic testicular cancer and prolong survival for patients suffering from ovarian, head and neck, bladder and non small cell lung cancer. Tumors that initially respond to treatment may eventually acquire resistance, resulting in treatment failure. Cisplatin resistant cells are crossresistant to arsenite and antimonite and these metalloids are exported from bacteria by the ars-operon.

    In this thesis, we describe the human ArsA homolog, ASNA1, as a protein involved in a novel resistance mechanism to cisplatin, arsenite and antimonite. ASNA1 was downregulated by antisense and siRNA techniques in human melanoma and ovarian carcinoma cell lines. These cells displayed increased sensitivity to arsenite and the platinum based drugs cisplatin, carboplatin and oxaliplatin. In both melanoma and ovarian carcinoma, cisplatin resistant cells overexpressed ASNA1.

    Blockage of ASNA1 resulted in increased apoptosis and retarded growth, complicating further characterization of ASNA1 in human cell lines. ASNA1 also promotes insulin signaling and mediates membrane insertion of tail-anchored proteins. To explore different aspects of ASNA1 function with respect to cisplatin resistance, we used the model organism C. elegans.

    In the nematode C. elegans, asna-1 (rnai) treated larvae were hypersensitive to cisplatin, arsenite and antimonite. Adult asna-1 mutant worms were cisplatin sensitive and this hypersensitivity was seen even when apoptosis was blocked. Expression of human ASNA1 rescued the cisplatin hypersensitivity in asna-1 mutants, showing conservation of function. Transgene expression of mutated forms of asna-1 separated the cisplatin hypersensitivity phenotype from the insulin signaling phenotype of asna-1 mutants. Three ASNA-1 residues, His164, Cys285 and Cys288 were identified as essential for ASNA-1 promoted cisplatin resistance but not for insulin signaling. Finally, studies of the C. elegans germline revealed increased numbers of apoptotic cells in asna-1 mutants.

    In conclusion, C. elegans is a suitable model organism to identify and characterize cisplatin response mechanisms. A targeted therapy against ASNA1 could sensitize cisplatin resistant cells and improve outcome for cancer patients.

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  • 256.
    Hemmingsson, Oskar
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Zhang, Youyi
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Still, Maria
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Naredi, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    ASNA1, an ATPase targeting tail-anchored proteins, regulates melanoma cell growth and sensitivity to cisplatin and arsenite2009In: Cancer Chemotherapy and Pharmacology, ISSN 0344-5704, E-ISSN 1432-0843, Vol. 63, no 3, p. 491-499Article in journal (Refereed)
    Abstract [en]

    Purpose ASNA1 is homologous to E. coli ArsA, a well characterized ATPase involved in efflux of arsenite and antimonite. Cells resistant to arsenite and antimonite are cross-resistant to the chemotherapeutic drug cisplatin. ASNA1 is also an essential ATPase for the insertion of tail-anchored proteins into ER membranes and a novel regulator of insulin secretion. The aim of this study was to determine if altered ASNA1 levels influenced growth and sensitivity to arsenite and cisplatin in human melanoma cells.

    Methods Cultured melanoma T289 cells were transfected with plasmids containing sense or antisense ASNA1. Cells were exposed to cisplatin, arsenite and zinc. Cell growth and chemosensitivity were evaluated by the MTT assay and apoptosis by a TUNEL assay.

    Results ASNA1 expression was necessary for growth. T289 clones with decreased ASNA1 expression exhibited 51 ± 5% longer doubling times than wildtype T289 (P = 0.0091). After exposure to cisplatin, ASNA1 downregulated cells displayed a significant increase in apoptosis. The cisplatin IC50 in ASNA1 underexpressing cells was 41.7 ± 1.8% compared to wildtype (P = 0.00097) and the arsenite IC50 was 59.9 ± 3.2% of wildtype IC50 (P = 0.0067).

    Conclusions Reduced ASNA1 expression is associated with significant inhibition of cell growth, increased apoptosis and increased sensitivity to cisplatin and arsenite.

  • 257.
    Henje, Catharina
    et al.
    Umeå universitet.
    Stenberg, Gunilla
    Umeå universitet.
    Carlsson, Anna
    Chalmers Tekniska Högskola.
    Lundälv, Jörgen
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Upplevda risker och problem i trafikmiljön för användare av elrullstol2019In: Sammanställning av referat från Transportforum 2019 / [ed] Camilla Ekström, Fredrik Hellman, Mattias Haraldsson, VTI (Statens väg- och transportforskningsinstitut) , 2019Conference paper (Other academic)
  • 258. Henriksson, M.
    et al.
    Bjornsson, B.
    Sternby Eilard, M.
    Lindell, G.
    Stromberg, C.
    Hemmingsson, Oskar
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Isaksson, B.
    Rizell, M.
    Sandstrom, P.
    Treatment patterns and survival in patients with hepatocellular carcinoma in the Swedish national registry SweLiv2020In: BJS Open, ISSN 2474-9842, Vol. 4, no 1, p. 109-117Article in journal (Refereed)
    Abstract [en]

    Background: Consistent data on clinical features, treatment modalities and long‐term survival in patients with hepatocellular carcinoma (HCC) using nationwide quality registers are lacking. This study aimed to describe treatment patterns and survival outcomes in patients diagnosed with HCC using a national maintained database.

    Methods: Characteristics and treatment patterns in patients diagnosed with HCC and registered in the national register of liver and bile duct tumours (SweLiv) between 2009 and 2016 were reviewed. Overall survival (OS) was estimated using Kaplan–Meier analysis and the log rank test to compare subgroups for clinical features, treatment modalities and outcomes according to the year of treatment.

    Results: A total of 3376 patients with HCC were registered over 8 years, 246 (7·3 per cent) of whom underwent transplantation. Some 501 (14·8 per cent) and 390 patients (11·6 per cent) had resection and ablation as primary treatment. Transarterial chemoembolization and systemic sorafenib treatment were intended in 476 (14·1 per cent) and 426 patients (12·6 per cent) respectively; the remaining 1337 (39·6 per cent) were registered but referred for best supportive care (BSC). The 5‐year survival rate was approximately 75 per cent in the transplantation group. Median OS was 4·6 (i.q.r. 2·0 to not reached) years after resection and 3·1 (2·3–6·7) years following ablation. In patients referred for palliative treatment, median survival was 1·4 (0·8–2·9), 0·5 (0·3–1·2) and 0·3 (0·1–1·0) years for the TACE, sorafenib and BSC groups respectively (P < 0·001). Median survival was 0·9 years for the total HCC cohort in 2009–2012, before publication of the Swedish national treatment programme, increasing to 1·4 years in 2013–2016 (P < 0·001).

    Conclusion: The survival outcomes reported were in line with previous results from smaller cohorts. The introduction of national guidelines may have contributed to improved survival among patients with HCC in Sweden.

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  • 259.
    Henriksson, Otto
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Protection against cold in prehospital trauma care2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Protection against cold is vitally important in prehospital trauma care to reduce heat loss and prevent body core cooling.

    Objectives: Evaluate the effect on cold stress and thermoregulation in volunteer subjects byutilising additional insulation on a spineboard (I). Determine thermal insulation properties of blankets and rescue bags in different wind conditions (II). Establish the utility of wet clothing removal or the addition of a vapour barrier by determining the effect on heat loss within different levels of insulation in cold and warm ambient temperatures (III) and evaluating the effect on cold stress and thermoregulation in volunteer subjects (IV).

    Methods: Aural canal temperature, sensation of shivering and cold discomfort was evaluated in volunteer subjects, immobilised on non-insulated (n=10) or insulated (n=9) spineboards in cold outdoor conditions (I). A thermal manikin was setup inside a climatic chamber and total resultant thermal insulation for the selected ensembles was determined in low, moderate and high wind conditions (II). Dry and wet heat loss and the effect of wet clothing removal or the addition of a vapour barrier was determined with the thermal manikin dressed in either dry, wet or no clothing; with or without a vapour barrier; and with three different levels of insulation in warm and cold ambient conditions (III). The effect on metabolic rate, oesophageal temperature, skin temperature, body heat storage, heart rate, and cold discomfort by wet clothing removal or the addition of a vapour barrier was evaluated in volunteer subjects (n=8), wearing wet clothing in a cold climatic chamber during four different insulation protocols in a cross-over design (IV).

    Results: Additional insulation on a spine board rendered a significant reduction of estimated shivering but there was no significant difference in aural canal temperature or cold discomfort (I). In low wind conditions, thermal insulation correlated to thickness of the insulation ensemble. In greater air velocities, thermal insulation was better preserved for ensembles that were windproof and resistant to the compressive effect of the wind (II). Wet clothing removal or the use of a vapour barrier reduced total heat loss by about one fourth in the cold environment and about one third in the warm environment (III). In cold stressed wet subjects, with limited insulation applied, wet clothing removal or the addition of a vapour barrier significantly reduced metabolic rate, increased skin rewarming rate, and improved total body heat storage but there was no significant difference in heart rate or oesophageal temperature cooling rate (IV). Similar effects on heat loss and cold stress was also achieved by increasing the insulation. Cold discomfort was significantly reduced with the addition of a vapour barrier and with an increased insulation but not with wet clothing removal.

    Conclusions: Additional insulation on a spine board might aid in reducing cold stress inprolonged transportations in a cold environment. In extended on scene durations, the use of a windproof and compression resistant outer cover is crucial to maintain adequate thermal insulation. In a sustained cold environment in which sufficient insulation is not available, wet clothing removal or the use of a vapour barrier might be considerably important reducing heat loss and relieving cold stress.

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  • 260.
    Henriksson, Otto
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lundgren, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Kuklane, Kalev
    Lunds universitet, Insitutionen för designvetenskaper.
    Holmér, Ingvar
    Lunds universitet, Insitutionen för designvetenskaper.
    Björnstig, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Protection against cold in prehospital care: thermal insulation properties of blankets and rescue bags in different wind conditions2009In: Prehospital and disaster medicine : the official journal of the National Association of EMS Physicians and the World Association for Emergency and Disaster Medicine in association with the Acute Care Foundation, ISSN 1049-023X, Vol. 24, no 5, p. 408-415Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: In a cold, wet, or windy environment, cold exposure can be considerable for an injured or ill person. The subsequent autonomous stress response initially will increase circulatory and respiratory demands, and as body core temperature declines, the patient's condition might deteriorate. Therefore, the application of adequate insulation to reduce cold exposure and prevent body core cooling is an important part of prehospital primary care, but recommendations for what should be used in the field mostly depend on tradition and experience, not on scientific evidence.

    OBJECTIVE: The objective of this study was to evaluate the thermal insulation properties in different wind conditions of 12 different blankets and rescue bags commonly used by prehospital rescue and ambulance services.

    METHODS: The thermal manikin and the selected insulation ensembles were setup inside a climatic chamber in accordance to the modified European Standard for assessing requirements of sleeping bags. Fans were adjusted to provide low (< 0.5 m/s), moderate (2-3 m/s) and high (8-9 m/s) wind conditions. During steady state thermal transfer, the total resultant insulation value, Itr (m2 C/Wclo; where C = degrees Celcius, and W = watts), was calculated from ambient air temperature (C), manikin surface temperature (C), and heat flux (W/m2).

    RESULTS: In the low wind condition, thermal insulation of the evaluated ensembles correlated to thickness of the ensembles, ranging from 2.0 to 6.0 clo (1 clo = 0.155 m2 C/W), except for the reflective metallic foil blankets that had higher values than expected. In moderate and high wind conditions, thermal insulation was best preserved for ensembles that were windproof and resistant to the compressive effect of the wind, with insulation reductions down to about 60-80% of the original insulation capacity, whereas wind permeable and/or lighter materials were reduced down to about 30-50% of original insulation capacity.

    CONCLUSIONS: The evaluated insulation ensembles might all be used for prehospital protection against cold, either as single blankets or in multiple layer combinations, depending on ambient temperatures. However, with extended outdoor, on-scene durations, such as during prolonged extrications or in multiple casualty situations, the results of this study emphasize the importance of using a windproof and compression resistant outer ensemble to maintain adequate insulation capacity.

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  • 261.
    Henriksson, Otto
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lundgren, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Kuklane, Kalev
    Lunds universitet, Institutionen för designvetenskaper.
    Holmér, Ingvar
    Lunds universitet, Institutionen för designvetenskaper.
    Giesbrecht, Gordon
    University of Manitoba.
    Naredi, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Björnstig, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Protection against cold - the effect on thermoregulation by wet clothing removal or addition of a vapour barrier in shivering subjectsManuscript (preprint) (Other academic)
  • 262.
    Henriksson, Otto
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lundgren, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Kuklane, Kalev
    Lunds universitet, Insitutionen för designvetenskaper.
    Holmér, Ingvar
    Lunds universitet, Insitutionen för designvetenskaper.
    Naredi, Peter
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Björnstig, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Protection against cold in prehospital care: evaporative heat loss reduction by wet clothing removal or the addition of a vapour barrier - a thermal manikin study2012In: Prehospital and Disaster Medicine, ISSN 1049-023X, E-ISSN 1945-1938, Vol. 26, no 6, p. 1-6Article in journal (Refereed)
    Abstract [en]

    Introduction: In the prehospital care of a cold and wet person, early application of adequate insulation is of utmost importance to reduce cold stress, limit body core cooling, and prevent deterioration of the patient’s condition. Most prehospital guidelines on protection against cold recommend the removal of wet clothing prior to insulation, and some also recommend the use of a waterproof vapor barrier to reduce evaporative heat loss. However, there is little scientific evidence of the effectiveness of these measures.

    Objective: Using a thermal manikin with wet clothing, this study was conducted to determine the effect of wet clothing removal or the addition of a vapor barrier on thermal insulation and evaporative heat loss using different amounts of insulation in both warm and cold ambient conditions.

    Methods: A thermal manikin dressed in wet clothing was set up in accordance with the European Standard for assessing requirements of sleeping bags, modified for wet heat loss determination, and the climatic chamber was set to -15 degrees Celsius (°C) for cold conditions and +10°C for warm conditions. Three different insulation ensembles, one, two or seven woollen blankets, were chosen to provide different levels of insulation. Five different test conditions were evaluated for all three levels of insulation ensembles: (1) dry underwear; (2) dry underwear with a vapor barrier; (3) wet underwear; (4) wet underwear with a vapor barrier; and (5) no underwear. Dry and wet heat loss and thermal resistance were determined from continuous monitoring of ambient air temperature, manikin surface temperature, heat flux and evaporative mass loss rate.

    Results: Independent of insulation thickness or ambient temperature, the removal of wet clothing or the addition of a vapor barrier resulted in a reduction in total heat loss of 19-42%. The absolute heat loss reduction was greater, however, and thus clinically more important in cold environments when little insulation is available. A similar reduction in total heat loss was also achieved by increasing the insulation from one to two blankets or from two to seven blankets.

    Conclusion: Wet clothing removal or the addition of a vapor barrier effectively reduced evaporative heat loss and might thus be of great importance in prehospital rescue scenarios in cold environments with limited insulation available, such as in mass-casualty situations or during protracted evacuations in harsh conditions.

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  • 263.
    Henriksson, Roger
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Capala, Jacek
    Michanek, Annika
    Lindahl, Sten-Åke
    Salford, Leif G
    Franzén, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Oncology.
    Blomquist, Erik
    Westlin, Jan-Erik
    Bergenheim, A Tommy
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Boron neutron capture therapy (BNCT) for glioblastoma multiforme.: A phase II study evaluating a prolonged high-dose of boronophenylalanine (BPA).2008In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 88, no 2, p. 183-191Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE:

    To evaluate the efficacy and safety of boron neutron capture therapy (BNCT) for glioblastoma multiforme (GBM) using a novel protocol for the boronophenylalanine-fructose (BPA-F) infusion.

    PATIENT AND METHODS:

    This phase II study included 30 patients, 26-69 years old, with a good performance status of which 27 have undergone debulking surgery. BPA-F (900 mg BPA/kg body weight) was given i.v. over 6h. Neutron irradiation started 2h after the completion of the infusion. Follow-up reports were monitored by an independent clinical research institute.

    RESULTS:

    The boron-blood concentration during irradiation was 15.2-33.7 microg/g. The average weighted absorbed dose to normal brain was 3.2-6.1 Gy (W). The minimum dose to the tumour volume ranged from 15.4 to 54.3 Gy (W). Seven patients suffered from seizures, 8 from skin/mucous problem, 5 patients were stricken by thromboembolism and 4 from abdominal disturbances in close relation to BNCT. Four patients displayed 9 episodes of grade 3-4 events (WHO). At the time for follow-up, minimum ten months, 23 out of the 29 evaluable patients were dead. The median time from BNCT treatment to tumour progression was 5.8 months and the median survival time after BNCT was 14.2 months. Following progression, 13 patients were given temozolomide, two patients were re-irradiated, and two were re-operated. Patients treated with temozolomide lived considerably longer (17.7 vs. 11.6 months). The quality of life analysis demonstrated a progressive deterioration after BNCT.

    CONCLUSION:

    Although, the efficacy of BNCT in the present protocol seems to be comparable with conventional radiotherapy and the treatment time is shorter, the observed side effects and the requirement of complex infrastructure and higher resources emphasize the need of further phase I and II studies, especially directed to improve the accumulation of (10)B in tumour cells.

  • 264.
    Hermansson, Cecilia
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Breast Cancer Liver Metastasis – Survival after Surgical Treatment2016Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 265. Hjortshoj, Cristel Sorensen
    et al.
    Jensen, Annette Schophuus
    Sorensen, Keld
    Nagy, Edit
    Johansson, Bengt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Cardiology.
    Kronvall, Thomas
    Dellborg, Mikael
    Estensen, Mette-Elise
    Holmstrom, Henrik
    Turanlahti, Maila
    Thilen, Ulf
    Sondergaard, Lars
    Epidemiological changes in Eisenmenger syndrome in the Nordic region in 1977-20122017In: Heart, ISSN 1355-6037, E-ISSN 1468-201X, Vol. 103, no 17, p. 1353-1358Article in journal (Refereed)
    Abstract [en]

    Objective: Improved diagnostic tools, timely closure of the shunt and a better understanding of the complexity of Eisenmenger syndrome (ES) have led to improved care and treatment in tertiary centres. These may have decreased the incidence of ES and improved survival of patients with ES, although evidence is still lacking. The aim of this study was to investigate temporal changes in incidence, prevalence and mortality in patients with ES for 35 years in the Nordic region.

    Methods: This was a retrospective population-based study including 714 patients with ES. Survival analysis was performed based on all-cause mortality and accounting for immortal time bias.

    Results: The incidence of ES decreased from 2.5/million inhabitants/year in 1977 to 0.2/million inhabitants/year in 2012. Correspondingly, prevalence decreased from 24.6 to 11.9/million inhabitants. The median survival was 38.4 years, with 20-year, 40-year and 60-year survival of 72.5%, 48.4%, and 21.3%, respectively. Complex lesions and Down syndrome were independently associated with worse survival (HR 2.2, p<0.001 and HR 1.8, p<0.001, respectively). Age at death increased from 27.7 years in the period from 1977 to 1992, to 46.3 years from July 2006 to 2012 (p<0.001).

    Conclusions: The incidence and prevalence of ES in the Nordic region have decreased markedly during the last decades. Furthermore, the median age at death increased throughout the study period, indicating prolonged life expectancy in the ES population. However, increasing age represents decreased incidence, rather than improved survival. Nonetheless, longevity with ES is still shorter than in the background population.

  • 266. Hodges, Gethin W.
    et al.
    Bang, Casper N.
    Eugen-Olsen, Jesper
    Olsen, Michael H.
    Boman, Kurt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ray, Simon
    Kesäniemi, Antero Y.
    Jeppesen, Jørgen L.
    Wachtell, Kristian
    SuPAR predicts postoperative complications and mortality in patients with asymptomatic aortic stenosis2018In: Open heart, E-ISSN 2053-3624, Vol. 5, no 1, article id e000743Article in journal (Refereed)
    Abstract [en]

    Background We evaluated whether early measurement of soluble urokinase plasminogen activator receptor (suPAR) could predict future risk of postoperative complications in initially asymptomatic patients with mild-moderate aortic stenosis (AS) undergoing aortic valve replacement (AVR) surgery.

    Methods Baseline plasma suPAR levels were available in 411 patients who underwent AVR surgery during in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study. Cox analyses were used to evaluate suPAR in relation to all-cause mortality and the composite endpoint of postoperative complications (all-cause mortality, congestive heart failure, stroke and renal impairment) occurring in the 30-day postoperative period.

    Results Patients with initially higher levels of suPAR were at increased risk of postoperative mortality with a HR of 3.5 (95% CI 1.4 to 9.0, P=0.008) and postoperative complications with a HR of 2.7 (95% CI 1.5 to 5.1, P=0.002), per doubling in suPAR. After adjusting for the European System for Cardiac Operative Risk Evaluation or Society of Thoracic Surgeons risk score, suPAR remained associated with postoperative mortality with a HR 3.2 (95% CI 1.2 to 8.6, P=0.025) and 2.7 (95% CI 1.0 to 7.8, P=0.061); and postoperative complications with a HR of 2.5 (95% CI 1.3 to 5.0, P=0.007) and 2.4 (95% CI 1.2 to 4.8, P=0.011), respectively.

    Conclusion Higher baseline suPAR levels are associated with an increased risk for postoperative complications and mortality in patients with mild-moderate, asymptomatic AS undergoing later AVR surgery. Further validation in other subsets of AS individuals are warranted.

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  • 267.
    Holgersson, Annelie
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Preparedness for mass-casualty attacks on public transportation2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Public transportation constitutes a vulnerable sector in modern day society with a high probability of generating mass casualties if attacked. By preparing for mass-casualty attacks (MCAs), response can become more effective and public transportation can become a less rewarding target. However, preparedness for attacks, much like response, implies resource constraints, and this dissertation pinpoints some major dilemmas that inhibit achieving preparedness for MCAs on public transportation in Sweden.

    Aim: The aim of this dissertation was to investigate preparedness for mass-casualty attacks on public transportation. This allowed for identification of major challenges for preparedness and response with a particular focus on the Swedish context.

    Methods: Study I included 477 MCAs identified through searches of the Global Terrorism Database, journals, newspapers and websites, which were examined with descriptive statistics. Study II thematically analyzed 105 articles attained by systematic searches of the PubMed and Scopus databases. Study III and IV statistically analyzed data from 864 responses to a purposive-designed questionnaire, from operational personnel of the Swedish emergency organizations. Study V entailed validation of a finite element (FE) simulation model of a bombing in a train carriage compared to the bombings in Madrid 2004.

    Results: International trends of MCAs (≥ 10 fatally injured and/or ≥ 100 non-fatally injured) on public transportation, during the years 1970-2009 (I) showed that the average number of injured increased considerably, despite a quite stable incidence rate since the 1980s. High numbers of injured people were connected to attacks on terminal buildings, multiple targets and complex tactical approaches. Few MCAs occurred in Europe, but the average number of fatalities per incident and injured per incident were the second highest among regions. The literature study (II) of previous on-scene management showed that commonly encountered challenges during unintentional incidents were added to during MCAs, implying specific issues for safety, assessment, triage and treatment, which require collaborative planning and specific training. The study regarding the Swedish emergency organizations’ perceptions of terrorist attacks (III) showed significant differences on perceptions of event likelihood, willingness to respond, estimated management capability and level of confidence in knowledge of tasks to be performed on scene. The police respondents stood out; e.g., fewer police personnel had high estimates of their organizations’ management capability and knowledge of tasks on-scene compared to the other organizations. The study of factors that influence responders’ perceptions of preparedness for terrorism (IV) showed that these were influenced by the responders’ sex, work experience, organizational affiliation, various training arrangements and access to personal protective equipment (PPE). Investing in amenable factors, such as terrorism-related management training and provision of PPE, could improve responders’ perceptions of preparedness for terrorism. A finite-element (FE) model of an explosion in a train carriage (V) was developed and showed that FE modeling techniques could effectively model damage and injuries for explosions with applicability for preparedness and injury mitigation efforts, but, also, there was room for improvement of the model in terms of injuries.

    Conclusion: Achieving preparedness for MCAs on public transportation is a multiple choice balancing act between ostensible dilemmas regarding investments, disaster plans, training, response strategies, collaboration and inventions.

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  • 268.
    Holmdahl, Viktor
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Properties of full-thickness skin - Mechanical properties and application of full-thickness skin grafts in parastomal hernia repair2017Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 269.
    Holmdahl, Viktor
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences. Sunderby Research Unit, Department of Surgical and Perioperative Sciences, Umeå University, Luleå, Sweden.
    Backman, Olof
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Gunnarsson, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Strigård, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    The Tensile Strength of Full-Thickness Skin: A Laboratory Study Prior to Its Use as Reinforcement in Parastomal Hernia Repair2019In: Frontiers in Surgery, ISSN 2296-875X, Vol. 6, article id 69Article in journal (Refereed)
    Abstract [en]

    Purpose: Parastomal hernia is a common complication of an enterostoma. Current methods of repair have high recurrence rates and are associated with severe complications. Autologous full-thickness skin as reinforcement may reduce the recurrence and complication rates. This study aims to investigates the tensile strength of full-thickness skin; information that is essential if we are to proceed with clinical trials on humans.

    Methods: Full-thickness skin samples from 12 donors were tested for tensile strength, as well as the load tolerated by a suture through the skin. Strips of skin were cut out and stretched until breaking point. Sutures were made through skin samples and traction applied until either the tissue or the suture gave way. All done while recording the forces applied using a dynamometer. Identical tests were carried out on commercially available synthetic and biologic graft material for comparison.

    Results: The full-thickness skin strips had a median tensile strength of 604 N/cm. This tensile strength was significantly higher than that of the compared materials evaluated in this study. In full-thickness skin, the suture, or tissue endured a median force of 67 N before giving way, which was as high as, or higher than similar sutures through the compared materials.

    Conclusions: The tensile strength of full-thickness skin vastly exceeds the physiological forces affecting the abdominal wall, and sutures through skin endure high loads before giving way. The tensile strength of a full-thickness skin graft and the strength of sutures through this material will not limit its use for reinforcement in parastomal hernia repair.

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  • 270.
    Holmdahl, Viktor
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Stark, Birgit
    Department of Molecular Medicine and Surgery, Karolinska Institute, Solna, Sweden..
    Clay, Leonard
    Department of Clinical Science and Education, Karolinska Institute, Solna, Sweden..
    Gunnarsson, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Strigård, Karin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    One-year outcome after repair of giant incisional hernia using synthetic mesh or full-thickness skin graft: a randomised controlled trial2019In: Hernia, ISSN 1265-4906, E-ISSN 1248-9204, Vol. 23, no 2, p. 355-361Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Repair of giant incisional hernia often requires complex surgery and the results of conventional methods using synthetic mesh as reinforcement are unsatisfactory, with high recurrence and complication rates. Our hypothesis was that full-thickness skin graft (FTSG) provides an alternative reinforcement material for giant incisional hernia repair and that outcome is improved. The aim of this study was to compare FTSG with conventional materials currently used as reinforcement in the repair of giant incisional hernia.

    METHODS: A prospective randomised controlled trial was conducted, comparing FTSG with synthetic mesh as reinforcement in the repair of giant (> 10 cm minimum width) incisional hernia. One-year follow-up included a blinded clinical examination by a surgeon and objective measurements of abdominal muscle strength using the Biodex-4 system.

    RESULTS: 52 patients were enrolled in the study: 24 received FTSG and 28 synthetic mesh. Four recurrences (7.7%) were found at 1-year follow-up, two in each group. There were no significant differences regarding pain, patient satisfaction or aesthetic outcome between the groups. Strength in the abdominal wall was not generally improved in the study population and there was no significant difference between the groups.

    CONCLUSION: The outcome of repair of giant incisional hernia using FTSG as reinforcement is comparable with repair using synthetic mesh. This suggests that FTSG may have a future place in giant incisional hernia repair.

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  • 271.
    Holmgren, Klas
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Permanent stoma after anterior resection for rectal cancer: prevalence and mechanisms2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    While sphincter-saving surgery constitutes standard treatment for rectal cancer, anterior resection still harbours a significant risk of a permanent stoma in the long run. Although anastomotic leakage plays a major role in this surgical dilemma, the exact mechanisms are not known, while surveys indicate a stoma-free outcome is essential for a majority of patients. To address this issue, the overall aim of the present thesis was to investigate the permanent stoma prevalence in patients undergoing anterior resection for rectal cancer in Sweden, and to identify plausible mechanisms that impede prospects of a stoma-free outcome.

    In a population-based cohort, chart review of patients who had anterior resection for rectal cancer in the Northern healthcare region in Sweden between 2007 and 2013 showed that 75 out of 316 (24%) patients ended up with a permanent stoma. Of 274 patients (87%) primarily defunctioned with a stoma, 229 underwent stoma closure, 21 (9%) of whom suffered major complications that required return to theatre or worse. A permanent stoma was shown to be more common among patients with anastomotic leakage and an advanced tumour stage.

    A registry-based method to estimate nationwide stoma outcome after anterior resection for rectal cancer was developed, using data from the Swedish Colorectal Cancer Registry and the National Patient Registry. With a chart-reviewed cohort as reference, stoma outcome was assessed with a positive predictive value of 85.1%, and a negative predictive value of 100.0%. In patients operated in Sweden between 2007 and 2013, the registry-based method determined that 942 out of 4768 (19.8%) had a permanent stoma, while stoma rates varied substantially between different healthcare regions.

    In a 1:1 matched case-control study of 82 patients who had curative resection for non-disseminated colorectal cancer, a subgroup analysis of 34 patients with rectal cancer displayed biomarker aberrations in serum measured preoperatively in those with anastomotic leakage. Compared to complication-free controls, 15 proteins related to inflammation were elevated, of which two (C-X-C motif chemokine 6, and C-C motif chemokine 11) remained significant after adjustment for multiple testing.

    Based on a cohort of 4529 patients who had anterior resection, tumour height served as a proxy to determine the extent of mesorectal excision, while long-term stoma outcome was classified using a previously validated registry-based method. Defunctioning stomas significantly decreased chances of a stoma-free outcome, especially in patients undergoing partial mesorectal excision; for these patients, faecal diversion was also least beneficial in terms of reducing anastomotic leakage.

    In conclusion, every fifth patient undergoing anterior resection for rectal cancer in Sweden eventually ends up with a permanent stoma. Although construction of a defunctioning stoma decreases the risk of symptomatic anastomotic leakage, subsequent takedown surgery carries a substantial risk of major complications, while chances of a long-term stoma-free outcome become significantly reduced. To facilitate selective use of faecal diversion, novel markers to identify high-risk anastomoses prior to surgery have been identified, but require validation in larger prospective settings. Anterior resection without a defunctioning stoma should be considered in appropriately informed patients for whom a stoma-free outcome is of importance. In particular, this holds true for patients eligible for partial mesorectal excision, where anastomotic dehiscence is less frequent and the advantageous effects of a defunctioning stoma are limited.

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  • 272.
    Holmgren, Klas
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Haapamäki, Markku M.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Matthiessen, Peter
    Rutegård, Jörgen
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Rutegård, Martin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery. Umeå University, Faculty of Medicine, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Anterior resection for rectal cancer in Sweden: validation of a registry-based method to determine long-term stoma outcome2018In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 57, no 12, p. 1631-1638Article in journal (Refereed)
    Abstract [en]

    Background: A permanent stoma after anterior resection for rectal cancer is common. Nationwide registries provide sufficient power to evaluate factors influencing this phenomenon, but validation is required to ensure the quality of registry-based stoma outcomes.

    Methods: Patients who underwent anterior resection for rectal cancer in the Northern healthcare region of Sweden between 1 January 2007 and 31 December 2013 were reviewed by medical records and followed until 31 December 2014 with regard to stoma outcome. A registry-based method to determine nationwide long-term stoma outcomes, using data from the National Patient Registry and the Swedish Colorectal Cancer Registry, was developed and internally validated using the chart reviewed reference cohort. Accuracy was evaluated with positive and negative predictive values and Kappa values. Following validation, the stoma outcome in all patients treated with an anterior resection for rectal cancer in Sweden during the study period was estimated. Possible regional differences in determined stoma outcomes between the six Swedish healthcare regions were subsequently evaluated with the χ2 test.

    Results: With 312 chart reviewed patients as reference, stoma outcome was accurately predicted through the registry-based method in 299 cases (95.8%), with a positive predictive value of 85.1% (95% CI 75.8%-91.8%), and a negative predictive value of 100.0% (95% CI 98.4%-100.0%), while the Kappa value was 0.89 (95% CI 0.82-0.95). In Sweden, 4768 patients underwent anterior resection during the study period, of which 942 (19.8%) were determined to have a permanent stoma. The stoma rate varied regionally between 17.8-29.2%, to a statistically significant degree (p = .001).

    Conclusion: Using data from two national registries to determine long-term stoma outcome after anterior resection for rectal cancer proved to be reliable in comparison to chart review. Permanent stoma prevalence after such surgery remains at a significant level, while stoma outcomes vary substantially between different healthcare regions in Sweden.

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  • 273.
    Holmgren, Klas
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Häggström, Jenny
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Haapamäki, Markku M.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Matthiessen, Peter
    Department of Surgery, Faculty of Medicine and Health, School of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Rutegård, Jörgen
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Rutegård, Martin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Defunctioning stomas decrease chances of a stoma-free outcome after anterior resection for rectal cancerManuscript (preprint) (Other academic)
  • 274.
    Holmgren, Klas
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Jonsson, Pär
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lundin, Christina
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Matthiessen, Peter
    Department of Surgery, Faculty of Medicine and Health, School of Health and Medical Sciences, Örebro University, Örebro, Sweden.
    Rutegård, Jörgen
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Sund, Malin
    Umeå University, Faculty of Medicine, Department of Biobank Research. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Rutegård, Martin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Preoperative biomarkers related to inflammation identify high-risk anastomoses in surgery for rectal cancer: an explorative study on patients with colorectal cancerManuscript (preprint) (Other academic)
  • 275.
    Holmgren, Klas
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Kverneng Hultberg, Daniel
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Haapamäki, Markku M.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Matthiessen, P.
    Rutegård, Jörgen
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Rutegård, Martin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    High stoma prevalence and stoma reversal complications following anterior resection for rectal cancer: a population-based multicentre study2017In: Colorectal Disease, ISSN 1462-8910, E-ISSN 1463-1318, Vol. 19, no 12, p. 1067-1075Article in journal (Refereed)
    Abstract [en]

    AIM: Fashioning a defunctioning stoma is common when performing an anterior resection for rectal cancer in order to avoid and mitigate the consequences of an anastomotic leakage. We investigated the permanent stoma prevalence, factors influencing stoma outcome and complication rates following stoma reversal surgery.

    METHOD: Patients who had undergone an anterior resection for rectal cancer between 2007 and 2013 in the northern healthcare region were identified using the Swedish Colorectal Cancer Registry and were followed until the end of 2014 regarding stoma outcome. Data were retrieved by a review of medical records. Multiple logistic regression was used to evaluate predefined risk factors for stoma permanence. Risk factors for non-reversal of a defunctioning stoma were also analysed, using Cox proportional-hazards regression.

    RESULTS: A total of 316 patients who underwent anterior resection were included, of whom 274 (87%) were defunctioned primarily. At the end of the follow-up period 24% had a permanent stoma, and 9% of patients who underwent reversal of a stoma experienced major complications requiring a return to theatre, need for intensive care or mortality. Anastomotic leakage and tumour Stage IV were significant risk factors for stoma permanence. In this series, partial mesorectal excision correlated with a stoma-free outcome. Non-reversal was considerably more prevalent among patients with leakage and Stage IV; Stage III patients at first had a decreased reversal rate, which increased after the initial year of surgery.

    CONCLUSION: Stoma permanence is common after anterior resection, while anastomotic leakage and advanced tumour stage decrease the chances of a stoma-free outcome. Stoma reversal surgery entails a significant risk of major complications.

  • 276.
    Holmgren, Klas
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Kverneng Hultberg, Daniel
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Haapamäki, Markku M
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Rutegård, Jörgen
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Matthiessen, P
    Rutegård, Martin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Reply to: 'High stoma prevalence and stoma reversal complications following anterior resection for rectal cancer: a population‐based multicentre study'2018In: Colorectal Disease, ISSN 1462-8910, E-ISSN 1463-1318, Vol. 20, no 4, p. 342-343Article in journal (Refereed)
  • 277. Holmquist, Per
    et al.
    Dasmah, Amir
    Sennerby, Lars
    Hallman, Mats
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Surgery. Clinic for Oral & Maxillofacial Surgery, Gävle Hospital, Gävle, Sweden.
    A new technique for reconstruction of the atrophied narrow alveolar crest in the maxilla using morselized impacted bone allograft and later placement of dental implants2008In: Clinical Implant Dentistry and Related Research, ISSN 1523-0899, E-ISSN 1708-8208, Vol. 10, no 2, p. 86-92Article in journal (Refereed)
    Abstract [en]

    Background: In cases when the alveolar crest is too narrow to host an implant, lateral augmentation is required. The use of autogenous bone blocks harvested from the iliac crest is often demanded. One disadvantage is the associated patient morbidity.

    Purpose: The purpose of this study was to clinically and histologically evaluate the use of morselized impacted bone allograft, a novel technique for reconstruction of the narrow alveolar crest.

    Materials and methods: Two patients with completely edentulous maxillae and one partially edentulous, with a mean age of 77 years (range 76-79 years) were included in the study. The alveolar crest width was < 3 mm without possibility to place any implant. Bone grafts were taken from a bone bank in Gavle Hospital. Bone from the neck of femur heads was milled to produce bone chips. The milled bone was partially defatted by rinsing in 37 degrees C saline solution. After compression of the graft pieces with a size of 15 mm (height), 30 mm (length), and 6 mm (width), they were then fit to adapt to the buccal surface of the atrophied alveolar crest. One piece was placed to the right and one to the left side of the midline. On both sides fibrin glue was used (Tisseel (R), Baxter AG, Vienna, Austria) to stabilize the graft. After 6 months of graft healing, dental implants were placed, simultaneously biopsies were harvested and in one patient two oxidized microimplants were placed. At the time of abutment connection, microimplants were retrieved with surrounding bone for histology. Fixed screw-retained bridges were fabricated in mean of 7 months after implant surgery. Radiographs were taken before and after implant surgery and after 1 year of loading.

    Results: Sixteen implants with an oxidized surface were placed (TiUnite (R), Nobel Biocare AB, Goteborg, Sweden). After 1 year of functional loading, all implants were clinically stable. The marginal bone loss was 1.4 mm (SD 0.3) after 1 year of loading. The histological examination showed resorption and subsequent bone formation on the allograft particles. There were no signs of inflammatory cell infiltration in conjunction with the allograft. The two microimplants showed bone formation directly on the implant surface.

    Conclusions: This study shows that morselized impacted bone allograft can be used to increase the width of the atrophied narrow alveolar crest as a good alternative to autogenous bone grafts in elderly patients. The histological examination of biopsies revealed a normal incorporation process and no signs of an immunological reaction. Further studies with larger samples are of important to be able to conclude if equal results can be obtained using morselized impacted bone allograft as for autogenous bone graft.

  • 278.
    Holsti, Mari
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Vascular remodelling and circulating basement membrane fragments in abdominal aortic aneurysm2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    An abdominal aortic aneurysm (AAA) is a degenerative disease, characterized by advanced inflammation and extracellular matrix (ECM) remodelling. Enhanced protease activity mediated by cytokines results in the degradation of ECM proteins, leading to the generation of different bioactive fragments. Some of these generated fragments are released from the vascular basement membrane (VBM), a highly specialized ECM. VBM provides mechanical and structural stability and regulates many important cellular functions of the vascular system. Type IV and XVIII collagens are two structural proteins in VBM, with crucial roles in maintaining of the VBM integrity and vascular architecture. Circulating levels of type IV and XVIII collagen fragments are found physiologically, but have also been associated with many diseases. Remodelling of VBM and expression of its components has not been as well studied in AAA as that of the interstitial ECM.

    Here we investigate these VBM collagens, their expression and possible association with aortic diameter and expansion rate in individuals with an AAA in comparison with different control groups. Further we study whether there is a link between the circulating VBM collagen fragments and several inflammatory markers, all highly involved in AAA pathogenesis. Lastly, we study the impact of surgical intervention on plasma levels of VBM collagens in patients treated by either open surgical repair (OSR) or endovascular aortic aneurysm repair (EVAR).

    Methods: Circulating levels of type IV and XVIII collagen fragments were analysed in individuals with an AAA and compared with healthy controls and patients with peripheral artery disease (paper I). A possible association between VBM collagen fragments and the aortic diameter and expansion was studied in a large population-based cohort of 615 men stratified into three aortic diameter groups based on initial maximum aortic diameter (paper II). Furthermore, 159 individuals were followed up over time with repeated measurements of aortic diameter and blood samples. The follow up cohort were divided into two subgroups based on expansion rate of AAA. Moreover, the location of VBM collagens in tissue from aortic wall in individuals with an AAA was characterized and the expression pattern was compared with normal aorta (paper II). In paper III, the association between the plasma levels of VBM collagens and inflammatory markers; IL-1 (IL-1α and IL-1β), IL-6, IL-8, TNF-α INF-γ and hs-CRP were studied in same cohort as paper II. Finally, the effect of surgical intervention on circulating levels of VBM collagen fragments was investigated in AAA patients who had undegone either OSR or EVAR by comparison of plasma levels before and after AAA repair.

    Ultrasound technique was used for measurements of aortic diameter (paper I, II, III and IV). Analysis of circulating VBM collagens and inflammatory markers were performed by ELISA-assay (Paper I, II, III and IV) and Multiplex-assays, respectively (paper III). Aortic wall tissues were analysed by haematoxylin and eosin (H&E) and immunofluorescence staining (Paper II).

    Results: There were significantly increased plasma levels of VBM collagen fragments in individuals with an AAA, compared with healthy controls and individulas with a peripheral artery disease (PAD), (Paper I). The levels of type IV collagen in AAA patients did not differ from the group with PAD, and there were no significant differences between the control groups regarding plasma levels of both VBM collagen fragments (Paper I). The increased levels of VBM collagen fragments were significantly associated with aortic diameter with highest levels in the group with an AAA (Paper II). Altered expression of the VBM collagens and fragmentation of elastic fibres were observed in tissue from AAA patients (Paper II). A significant association between the levels of pro-inflammatory cytokines IL-6 and IL-8, and VBM collagens was found. Additionally, there were a significant association between the plasma levels of IL-8, TNF-α and hs-CRP and an AAA (Paper III). Aneurysms with faster expansion rate had significantly higher levels of IL-6, IL-1β, and type XVIII/endostatin collagen. Additionally, IL-6, type XVIII/endostatin collagen and baseline-aortic diameter were significantly associated with expansion rate (Paper III). AAA repair was associated with changes in plasma levels of VBM collagens (Paper IV).

    Conclusion: Circulating levels of VBM collagens were increased in patients with an AAA, and significantly associated with aortic diameter and expansion rate. The expression of VBM collagens was altered in AAA tissue compared with normal aorta. In addition, plasma levels of several inflammatory markers were associated as with VBM collagens, aortic diameter and expansion rate. The levels of both VBM collagens were altered at short and long time after AAA repair. 

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  • 279.
    Holsti, Mari
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Wanhainen, Anders
    Lundin, Christina
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Björck, Martin
    Tegler, Gustaf
    Svensson, Johan
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Sund, Malin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Circulating Vascular Basement Membrane Fragments are Associated with the Diameter of the Abdominal Aorta and Their Expression Pattern is Altered in AAA Tissue2018In: European Journal of Vascular and Endovascular Surgery, ISSN 1078-5884, E-ISSN 1532-2165, Vol. 56, no 1, p. 110-118Article in journal (Refereed)
    Abstract [en]

    Objective: Abdominal aortic aneurysm (AAA) is characterised by enhanced proteolytic activity, and extracellular matrix (ECM) remodelling in the vascular wall. Type IV and XVIII collagen/endostatin are structural proteins in vascular basement membrane (VBM), a specialised ECM structure. Here the association between plasma levels of these collagens with the aortic diameter and expansion rate is studied, and their expression in aortic tissue characterised. Methods: This was a retrospective population based cohort study. Type IV and XVIII collagen/endostatin were analysed in plasma by ELISA assay in 615 men, divided into three groups based on the aortic diameter: 1) normal aorta <= 25 mm, 2) sub-aneurysmal aorta (SAA) 26-29 mm, and 3) AAA >= 30 mm. Follow up data were available for 159 men. The association between collagen levels and aortic diameter at baseline, and with the expansion rate at follow up were analysed in ordinal logistic regression and linear regression models, controlling for common confounding factors. Tissue expression of the collagens was analysed in normal aorta (n = 6) and AAA (n = 6) by immunofluorescence. Results: Plasma levels of type XVIII collagen/endostatin (136 ng/mL [SD 29] in individuals with a normal aorta diameter, 154 ng/ml [SD 45] in SAA, and 162 ng/ml [SD 46] in AAA; p = .001) and type IV collagen (105 ng/mL [SD 42] normal aorta, 124 ng/ml [SD 46] SAA, and 127 ng/ml [SD 47] AAA; p = .037) were associated with a larger aortic diameter. A significant association was found between the baseline levels of type XVIII/endostatin and the aortic expansion rate (p = .035), but in the multivariable model, only the initial aortic diameter remained significantly associated with expansion (p = .005). Altered expression patterns of both collagens were observed in AAA tissue. Conclusion: Plasma levels of circulating type IV and XVIII collagen/endostatin increase with AAA diameter. The expression pattern of VBM proteins is altered in the aneurysm wall.

  • 280.
    Holsti, Mari
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Wanhainen, Anders
    Department of Surgical Sciences, Section of Vascular Surgery, Uppsala Universitet.
    Lundin, Christina
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Mani, Kevin
    Department of Surgical Sciences, Section of Vascular Surgery, Uppsala Universitet.
    Sund, Malin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Svensson, Johan
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Effect of aortic aneurysm treatment on circulating levels of vascular basement membrane fragments: a pilot studyManuscript (preprint) (Other academic)
  • 281.
    Holsti, Mari
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Wanhainen, Anders
    Department of Surgical Sciences, Section of Vascular Surgery, Uppsala Universitet.
    Lundin, Christina
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Svensson, Johan
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Björck, Martin
    Department of Surgical Sciences, Section of Vascular Surgery, Uppsala Universitet.
    Sund, Malin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Association of inflammatory cytokines to vascular wall remodelling and the aortic diameterManuscript (preprint) (Other academic)
  • 282. Honda, Kazufumi
    et al.
    Katzke, Verena A.
    Hüsing, Anika
    Okaya, Shinobu
    Shoji, Hirokazu
    Onidani, Kaoru
    Olsen, Anja
    Tjønneland, Anne
    Overvad, Kim
    Weiderpass, Elisabete
    Vineis, Paolo
    Muller, David
    Tsilidis, Kostas
    Palli, Domenico
    Pala, Valeria
    Tumino, Rosario
    Naccarati, Alessio
    Panico, Salvatore
    Aleksandrova, Krasimira
    Boeing, Heiner
    Bueno-de-Mesquita, H. Bas
    Peeters, Petra H.
    Trichopoulou, Antonia
    Lagiou, Pagona
    Khaw, Kay-Tee
    Wareham, Nick
    Travis, Ruth C.
    Merino, Susana
    Duell, Eric J.
    Rodríguez-Barranco, Miguel
    Chirlaque, María Dolores
    Barricarte, Aurelio
    Rebours, Vinciane
    Boutron-Ruault, Marie-Chiristine
    Romana Mancini, Francesca
    Brennan, Paul
    Scelo, Ghislaine
    Manjer, Jonas
    Sund, Malin
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Öhlund, Daniel
    Canzian, Federico
    Kaaks, Rudolf
    CA19-9 and apolipoprotein-A2 isoforms as detection markers for pancreatic cancer: a prospective evaluation2019In: International Journal of Cancer, ISSN 0020-7136, E-ISSN 1097-0215, Vol. 144, no 8, p. 1877-1887Article in journal (Refereed)
    Abstract [en]

    Recently, we identified unique processing patterns of apolipoprotein A2 (ApoA2) in patients with pancreatic cancer. Our study provides a first prospective evaluation of an ApoA2 isoform ("ApoA2-ATQ/AT"), alone and in combination with carbohydrate antigen 19-9 (CA19-9), as an early detection biomarker for pancreatic cancer. We performed ELISA measurements of CA19-9 and ApoA2-ATQ/AT in 156 patients with pancreatic cancer and 217 matched controls within the European EPIC cohort, using plasma samples collected up to 60 months prior to diagnosis. The detection discrimination statistics were calculated for risk scores by strata of lag-time. For CA19-9, in univariate marker analyses, C-statistics to distinguish future pancreatic cancer patients from cancer-free individuals were 0.80 for plasma taken ≤6 months before diagnosis, and 0.71 for >6-18 months; for ApoA2-ATQ/AT, C-statistics were 0.62, and 0.65, respectively. Joint models based on ApoA2-ATQ/AT plus CA19-9 significantly improved discrimination within >6-18 months (C = 0.74 vs. 0.71 for CA19-9 alone, p = 0.022) and ≤ 18 months (C = 0.75 vs. 0.74, p = 0.022). At 98% specificity, and for lag times of ≤6, >6-18 or ≤ 18 months, sensitivities were 57%, 36% and 43% for CA19-9 combined with ApoA2-ATQ/AT, respectively, vs. 50%, 29% and 36% for CA19-9 alone. Compared to CA19-9 alone, the combination of CA19-9 and ApoA2-ATQ/AT may improve detection of pancreatic cancer up to 18 months prior to diagnosis under usual care, and may provide a useful first measure for pancreatic cancer detection prior to imaging.

  • 283. Hovelius, Lennart
    et al.
    Olofsson, Anders
    Department of Orthopedics, Gävle Hospital.
    Sandström, Björn
    Department of Orthopedics, Gävle Hospital.
    Augustini, Bengt-Göran
    Läkargruppen AB, Örebro.
    Krantz, Lars
    Orthopedic Department, Högalidssjukhuset, Eksjö.
    Fredin, Hans
    Läkargruppen St Petri, Malmö.
    Tillander, Bo
    Department of Orthopedics, University Hospital, Linköping.
    Skoglund, Ulf
    Department of Orthopedics, Karlstad Hospital.
    Salomonsson, Björn
    Department of Orthopedics, Danderyd Hospital.
    Nowak, Jan
    Department of Orthopedics, Samariterhemmet, Uppsala.
    Sennerby, Ulf
    Department of Orthopedics, Nordfjord Hospital, Norway .
    Non-operative treatment of primary anterior shoulder dislocation in patients forty years of age and younger: a prospective twenty-five-year follow-up2008In: Journal of Bone and Joint Surgery. American volume, ISSN 0021-9355, E-ISSN 1535-1386, Vol. 90, no 5, p. 945-952Article in journal (Refereed)
    Abstract [en]

    Background: During 1978 and 1979, we initiated a prospective multicenter study to evaluate the results of nonoperative treatment of primary anterior shoulder dislocation. In the current report, we present the outcome after twenty-five years.

    Methods: Two hundred and fifty-five patients (257 shoulders) with an age of twelve to forty years who had a primary anterior shoulder dislocation were managed with immobilization (achieved by tying the arm to the torso with use of a bandage) or without immobilization. All 227 living patients (229 shoulders) completed the follow-up questionnaire, and 214 patients completed the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire.

    Results: Ninety-nine (43%) of 229 shoulders had not redislocated, and seventeen (7%) redislocated once. Thirty-three recurrent dislocations had become stable over time (14.4%), and eighteen were considered to be still recurrent (7.9%). Sixty-two shoulders (27%) had undergone surgery for the treatment of recurrent instability. Immobilization after the primary dislocation did not change the prognosis. Only two of twenty-four shoulders with a fracture of the greater tuberosity at the time of the primary dislocation redislocated (p < 0.001). When shoulders with a fracture of the greater tuberosity were excluded, forty-four (38%) of 115 shoulders in patients who had been twelve to twenty-five years of age at the time of the original dislocation and sixteen (18%) of ninety shoulders in patients who had been twenty-six to forty years of age had undergone surgical stabilization. At twenty-five years, fourteen (23%) of sixty-two shoulders that had undergone surgical stabilization were in patients who subsequently had a contralateral dislocation, compared with seven (7%) of ninety-nine shoulders in patients in whom the index dislocation had been classified as solitary (p = 0.01). Gender and athletic activity did not appear to affect the redislocation rate; however, women had worse DASH scores than men did (p = 0.006).

    Conclusions: After twenty-five years, half of the primary anterior shoulder dislocations that had been treated nonoperatively in patients with an age of twelve to twenty-five years had not recurred or had become stable over time.

    Level of Evidence: Prognostic Level I. See Instructions to Authors for a complete description of levels of evidence.

  • 284.
    Hovelius, Lennart
    et al.
    Orthopedic Department, Gävle Hospital, Gävle, Sweden.
    Saeboe, Modolv
    Radiologic Department, Bollnäs Hospital, Bollnäs.
    Neer Award 2008: Arthropathy after primary anterior shoulder dislocation: 223 shoulders prospectively followed up for twenty-five years2009In: Journal of shoulder and elbow surgery, ISSN 1058-2746, E-ISSN 1532-6500, Vol. 18, no 3, p. 339-347Article in journal (Refereed)
  • 285.
    Hovelius, Lennart
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Sandström, Björn
    Olofsson, Anders
    Svensson, Olle
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Orthopaedics.
    Rahme, Hans
    The effect of capsular repair, bone block healing, and position on the results of the Bristow-Laterjet procedure (study III): long-term follow-up in 319 shoulders2012In: Journal of shoulder and elbow surgery, ISSN 1058-2746, E-ISSN 1532-6500, Vol. 21, no 5, p. 647-660Article in journal (Refereed)
    Abstract [en]

    Background We evaluated the results of the May modification of the Bristow-Latarjet procedure (“coracoid in standing position”) in 319 shoulders with respect to (1) coracoid healing and position and (2) surgical treatment of the joint capsule.

    Methods From 1980 until 2004, all shoulders with a Bristow-Latarjet repair were registered at our hospital. This study consists of 3 different cohorts with respect to follow-up. Series 1, 118 shoulders operated on during 1980 through 1985, had 15 years’ radiographic and clinical follow-up. Series 2, 167 shoulders that had surgery during 1986 through 1999, underwent retrospective follow-up by a questionnaire and scores—Western Ontario Shoulder Instability Index; Disabilities of the Arm, Shoulder and Hand; and Subjective Shoulder Value—after 10 to 23 years. Series 3, 34 shoulders treated during 2000 through 2004, with an added modified Bankart repair (“capsulopexy”) in 33 shoulders, were prospectively followed up for 5 to 8 years with the same questionnaire and scores as series 2.

    Results Of 319 shoulders, 16 (5%) had 1 or more redislocations and 3 of these (1%) had revision surgery because of remaining instability. One or more subluxations were reported in 41 shoulders (13%). The worst scores were found in 16 shoulders with 2 or more subluxations (P < .001). Radiographs showed bony healing in 246 of 297 shoulders (83%), fibrous union in 34 (13%), migration by 0.5 cm or more in 14 (5%), and no visualization in 3 (1%). Five of six shoulders that had the transplant positioned 1 cm or more medial to the glenoid rim had redislocations (83%, P = .001). Shoulders with migrated transplants did not differ from those with bony or fibrous healing with respect to redislocations and subluxations. When just a horizontal capsular shift was added to the transfer, the recurrence rate (redislocations or subluxations) decreased, with 2 of 53 (4%)compared with 37 of 208 (18%) with just anatomic closure of the capsule (P = .005), and the Western Ontario Shoulder Instability Index score improved (92 vs 85.6, P = .048). In total, for 307 of 319 shoulders (96%), patients were satisfied or very satisfied at final follow-up.

    Conclusion The open Bristow-Latarjet procedure yields good and consistent results, with bony fusion of the coracoid in 83%. A position of the coracoid 1 cm or more medial to the rim meant significantly more recurrences. The rate of recurrences decreased and subjective results improved when a horizontal capsular shift was added to the coracoid transfer.

  • 286. Hultman, Bo
    et al.
    Gunnarsson, Ulf
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Nygren, Peter
    Sundbom, Magnus
    Glimelius, Bengt
    Mahteme, Haile
    Prognostic factors in patients with loco-regionally advanced gastric cancer2017In: World Journal of Surgical Oncology, ISSN 1477-7819, E-ISSN 1477-7819, Vol. 15, article id 172Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The aim of this study was to investigate epidemiologic and prognostic factors relevant to the treatment of loco-regionally advanced gastric cancer (GC).

    METHODS: Two hundred and fifty-five patients with GC were identified in Uppsala County between 2000 and 2009. Patient records were analyzed for loco-regionally advanced GC defined as tumor with peritoneal involvement, excluding serosal invasion from the primary tumor only, at primary diagnosis or during follow-up. The presence or not of distant metastasis (DM), including hematogenous metastases (e.g., liver, lung, and bone) and/or distant lymph node metastases, was also analyzed. The Cox proportional hazard model was used for multivariate analysis of factors influencing survival.

    RESULTS: One hundred and twenty patients (47% of all patients with GC; median age 70.5 years) had loco-regionally advanced disease, corresponding to an incidence of 3.8 per 100,000 person-years. Forty-one percent of these also had DM. Median overall survival (mOS) from the time of the diagnosis of loco-regionally advanced disease was 4.8 months for the total patient cohort, 5.1 months for the subgroup of patients without DM, and 4.7 months for the subgroup with DM. There was no significant difference in mOS between the subgroups with synchronous versus metachronous loco-regionally advanced GC: 4.8 months (range 0.0-67.4) versus 4.7 months (range 0.0-28.3). Using multivariate Cox analysis, positive prognostic factors for survival were good performance status at diagnosis and treatment with palliative chemotherapy and/or radiotherapy. Synchronous DM was a negative prognostic factor. The mOS did not differ when comparing the time period 2000-2004 (5.1 months, range 0-67.4) with the period 2005-2009 (4.0 months, range 0.0-28.3).

    CONCLUSION: Peritoneal involvement occurred in almost half of the patients with GC in this study and was associated with short life expectancy. New treatment strategies are warranted.

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  • 287. Huotarinen, Antti
    et al.
    Kivisaari, Riku
    Hariz, Marwan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Unit of Functional Neurosurgery, University College London – Institute of Neurology, London, United Kingdom.
    Laitinen's Subgenual Cingulotomy: Anatomical Location and Case Report2018In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 96, no 5, p. 342-346Article in journal (Refereed)
    Abstract [en]

    Background: The widespread use of deep brain stimulation (DBS) for movement disorders has renewed the interest in DBS for psychiatric disorders. Lauri Laitinen was a pioneer of stereotactic psychosurgery in the 1950s to 1970s, especially by introducing the subgenual cingulotomy. Our aim here was to verify the anatomical target used by Laitinen, to report on a patient who underwent this procedure, and to review the literature. Materials and Methods: The records of Helsinki University Hospital were searched for psychosurgical cases performed between 1970 and 1974. Alive consenting patients were interviewed and underwent a brain MRI. Results: We found 1 patient alive who underwent subgenual cingulotomy in 1971 for obsessive thoughts, anxiety, and compulsions, diagnosed at that time as "schizophrenia psychoneurotica." MRI showed bilateral subgenual cingulotomy lesions (254 and 160 mm(3), respectively). The coordinates of the center of the lesions in relation to the midcommissural point for the right and left, respectively, were: 7.1 and 7.9 mm lateral; 0.2 mm inferior and 1.4 mm superior, and 33.0 and 33.9 anterior, confirming correct subgenual targeting. The patient reported retrospective satisfactory results. Conclusions: The lesion in this patient was found to be in the expected location, which gives some verification of the correct placement of Laitinen's subgenus cingulotomy target.

  • 288.
    Hurtig, Jennie
    et al.
    Sunderby sjukhus - Allmänkirurgi Luleå, Sweden Sunderby sjukhus - Allmänkirurgi Lulea, Sweden..
    Gkekas, Ioannis
    Sunderby sjukhus - Allmänkirurgi Luleå, Sweden Sunderby sjukhus - Allmänkirurgi Lulea, Sweden..
    Näsvall, Pia
    Sunderby sjukhus - Allmänkirurgi Luleå, Sweden Sunderby sjukhus - Allmänkirurgi Lulea, Sweden..
    Vandrande mjälte – ovanlig men viktig differentialdiagnos vid akut buksmärta hos barn2018In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 115, no 47, article id FA9ZArticle in journal (Other academic)
    Abstract [en]

    Wandering spleen is a rare reason for acute abdominal pain in pediatric patients caused by laxity of the splenic ligaments. It can be complicated by torsion of the pedicle, leading to ischemia, a situation that in most cases results in acute abdominal surgery. To prevent ischemia of a mobile spleen caused by a total occlusion of the pedicle, splenopexy can be considered. We present an unusual case where changes in the position of the operating table during diagnostic laparoscopy might have caused a total occlusion of the pedicle.

  • 289.
    Husberg, Britt
    et al.
    Karolinska University Hospital Huddinge, Department of Surgical Gastroenterology, Stockholm, Sweden.
    Malmborg, P
    Karolinska University Hospital Huddinge, Department of Surgical Gastroenterology, Stockholm, Sweden.
    Strigård, Karin
    Karolinska University Hospital Huddinge, Department of Surgical Gastroenterology, Stockholm, Sweden.
    Treatment with botulinum toxin in children with chronic anal fissure.2009In: European journal of pediatric surgery, ISSN 0939-7248, E-ISSN 1439-359X, Vol. 19, no 5, p. 290-292Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Chronic anal fissures with painful defecation and bloodstained stools can be seen in children of all ages. Constipation may precede or appear in connection with the symptoms. Adult patients with anal fissures have been treated successfully with the injection of botulinum toxin into both the internal and external sphincter. The effect of botulinum toxin is reversible and lasts for 3-4 months. This pilot study attempted to examine whether botulinum toxin is also effective in paediatric cases of anal fissure, a treatment which not yet has been reported in the literature.

    MATERIAL AND METHODS: Six boys and seven girls aged 1-10 years were treated with botulinum toxin (Botox ((R))) during 2002-2005 due to chronic anal fissure. Conventional treatment with laxatives and local anaesthetics had been unsuccessful in all cases. The treatment was given to five children under 2 years of age in a dosage of 1.25 Ux2. Eight children over 2 years of age were given 2.5 Ux2. The injections were given in the external sphincter on both sides of the fissure using EMG-stimulation for guidance and were performed under light anaesthetics (Diprivan ((R))). Follow-up was conducted at 1 and 3 months after treatment.

    RESULTS: Within one week, 11 of the children were free from pain and blood stained stools, according to their parent's observations. One 10-year old patient initially showed some improvement but soon experienced a recurrence. After another injection with a higher dosage 2 months later, the fissure healed. One 4-year old patient did not show any signs of improvement. The laxatives, which had been withdrawn after the injection treatment, were then reinstated. At the 3 month post-treatment examination the patient was finally symptom-free with no signs of a fissure. There were no negative side-effects detected in any of the cases. Seven recurrences were noted in 6 of the patients after 3-30 months, often in connection with an episode of constipation. Repeat injections were offered and accepted by four of these patients, once more producing good immediate results.

    CONCLUSION: Treatment with botulinum toxin in the external sphincter produces a quick and effective alleviation of pain with healing of chronic anal fissures in children. The treatment is not considered to carry any risks but requires light anaesthesia. Recurrences are common after the pharmacological effect has receded but can be cured with an additional injection.

  • 290. Hyam, Jonathan A
    et al.
    Akram, Harith
    Foltynie, Thomas
    Limousin, Patricia
    Hariz, Marwan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom.
    Zrinzo, Ludvic
    What You See Is What You Get: Lead Location Within Deep Brain Structures Is Accurately Depicted by Stereotactic Magnetic Resonance Imaging2015In: Operative Neurosurgery, ISSN 2332-4252, Vol. 11, no 3, p. 412-419Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Magnetic resonance imaging (MRI)-verified deep brain stimulation relies on the correct interpretation of stereotactic imaging documenting lead location in relation to visible anatomic target. However, it has been suggested that local signal distortion from the lead itself renders its depiction on MRI unreliable. OBJECTIVE: To compare lead location on stereotactic MRI with subsequent location of its brain track after removal. METHODS: Patients underwent deep brain stimulation with the use of MRI-guided and MRI-verified Leksell frame approach. Infection or suboptimal efficacy required lead removal and subsequent reimplantation by using the same technique. Postimplantation stereotactic MR images were analyzed. Lateral (x) and anteroposterior (y) distances from midcommissural point to center of the lead hypointensity were recorded at the anterior commissure-posterior commissure plane (pallidal electrode) or z = 24 (subthalamic electrode). Stereotactic MRI before the second procedure, x and y distances from the center of the visible lead track hypointensity to midcommissural point were independently recorded. Vectorial distance from center of the lead hypointensity to the center of its track was calculated. RESULTS: Sixteen electrode tracks were studied in 10 patients. Mean differences between lead artifact location and lead track location were: x coordinate 0.4 mm +/- 0.2; y coordinate 0.6 mm +/- 0.3. Mean vectorial distance was 0.7 mm +/- 0.2. CONCLUSION: Stereotactic distance between lead location and subsequent brain track location on MRI was small. The mean discrepancy was approximately half the deep brain stimulation lead width. This suggests that lead hypointensity seen on postimplantation MRI is indeed an accurate representation of its real location within deep brain structures.

  • 291. Hägg, Shadi Amid
    et al.
    Emilsson, Össur I.
    Franklin, Karl A.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Janson, Christer
    Lindberg, Eva
    Nocturnal gastroesophageal reflux increases the risk of daytime sleepiness in women2019In: Sleep Medicine, ISSN 1389-9457, E-ISSN 1878-5506, Vol. 53, p. 94-100Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: Daytime sleepiness is common in women and has negative health effects. Nocturnal gastroesophageal reflux (nGER) and snoring are risk factors for daytime sleepiness, but the effect of their interaction remains unknown. The aim of this study was to examine how nGER and snoring combined affected daytime sleepiness and involuntary falling asleep in women.

    METHODS: A questionnaire was sent to randomly selected women in 2000 and 2010. Participants who answered questions regarding both nGER and snoring in both questionnaires were included (N = 4882). Daytime sleepiness was defined as severe or very severe problems with daytime sleepiness. Involuntary falling asleep was defined as sometimes, often or very often falling asleep involuntarily during the day. Respondents snoring loudly and disturbingly sometimes, often or very often were defined as snorers. Having nocturnal heartburn or acid reflux sometimes, often or very often was defined as having nGER.

    RESULTS: Daytime sleepiness was reported by 14% of the participants, involuntary falling asleep by 11%. After adjustment for age, smoking, physical activity, caffeine intake and alcohol dependency, increased odd ratios (ORs) for both daytime sleepiness (adjusted OR 4.2, 95% confidence interval (CI): 1.9-9.2) and involuntary falling asleep (adjusted OR 3.1, 95% CI: 1.5-6.4) were seen in women with the combination of nGER and snoring at both baseline and follow-up. The association with daytime sleepiness was also strong for those with only persistent nGER but not for those with only persistent snoring.

    CONCLUSION: Women with nGER were at increased risk of developing daytime sleepiness and snoring augmented this association. In addition, women with both nGER and snoring were also at increased risk of developing involuntary falling asleep.

  • 292.
    Häggman-Henrikson, Birgitta
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology. Department of Orofacial Pain and Jaw Function, Malmö University, Malmö.
    Rezvani, M.
    Department of Orofacial Pain and Jaw Function, Malmö University, Malmö.
    List, T.
    Department of Orofacial Pain and Jaw Function, Malmö University, Malmö and Department of Rehabilitation Medicine, Skåne University Hospital, Lund,.
    Prevalence of whiplash trauma in TMD patients: a systematic review2014In: Journal of Oral Rehabilitation, ISSN 0305-182X, E-ISSN 1365-2842, Vol. 41, no 1, p. 59-68Article, review/survey (Refereed)
    Abstract [en]

    The purpose of this systematic review was to describe the prevalence of whiplash trauma in patients with temporomandibular disorders (TMDs) and to describe clinical signs and symptoms in comorbid TMD/whiplash compared with TMD localised to the facial region. A systematic literature search of the PubMed, Cochrane Library and Bandolier databases was carried out for articles published from 1 January 1966 to 31 December 2012. The systematic search identified 129 articles. After the initial screening of abstracts, 32 articles were reviewed in full text applying inclusion and exclusion criteria. Six studies on the prevalence of neck trauma in patients with TMD met the inclusion criteria and were included in the review. Two of the authors evaluated the methodological quality of the included studies. The reported prevalence of whiplash trauma ranged from 84% to 70% (median 35%) in TMD populations, compared with 17-13% in the non-TMD control groups. Compared with patients with TMD localised to the facial region, TMD patients with a history of whiplash trauma reported more TMD symptoms, such as limited jaw opening and more TMD pain, and also more headaches and stress symptoms. In conclusion, the prevalence of whiplash trauma is higher in patients with TMD compared with non-TMD controls. Furthermore, patients with comorbid TMD/whiplash present with more jaw pain and more severe jaw dysfunction compared with TMD patients without a history of head-neck trauma. These results suggest that whiplash trauma might be an initiating and/or aggravating factor as well as a comorbid condition for TMD.

  • 293.
    Högström, Gabriel
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Pietilä, Tom
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Sports Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Body composition and performance: influence of sport and gender among adolescents2012In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 26, no 7, p. 1799-1804Article in journal (Refereed)
    Abstract [en]

    Body composition is well known to be associated with endurance performance amongst adult skiers, however the association among adolescent cross-country and alpine skiers is inadequately explored. The study sample was comprised of 145 male and female adolescent subjects (aged 15-17 years), including 48 cross-country skiers, 33 alpine skiers, and 68 control subjects. Body composition [%body fat, %lean mass, bone mineral density (g/cm2)] was measured with a dual-emission X-ray absorptiometer, and pulse and oxygen uptake were measured at three break points during incremental performance tests to determine physical fitness levels. Female cross-country and alpine skiers were found to have significantly higher %lean mass (mean difference = 7.7%, p < 0.001) and lower %body fat (mean difference = (8.1%, p < 0.001) than female control subjects. Male cross-country skiers were found to have lower %body fat (mean difference = 3.2%, p < 0.05) and higher %lean mass (mean difference = 3.3%, p < 0.01) than male alpine skiers and higher % lean mass (mean difference = 3.7%, p < 0.05) and % body fat (mean difference = 3.2%, p < 0.05) than controls. The present study found strong associations between %lean mass and the OBLA and VO2 max weight adjusted thresholds among both genders of the cross-country skiing cohort (r = 0.47-0.67, p < 0.05) and the female alpine skiing cohort (r = 0.77-0.79, p < 0.001 for all). The present study suggests that body composition is associated with physical performance already in adolescent athletes.

  • 294.
    Högström, Magnus
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences.
    Vitamins, fatty acids, physical activity and peak bone mass2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Osteoporosis is a disease characterized by low bone mineral density, deteriorated bone microstructure and increased fracture risk. About 50% of all women and 25% of all men will have an osteoporotic fracture. Given that there is no effective cure in established osteoporosis, prevention is of high importance. Bone mineral density (BMD) is accumulated during childhood and adolescence with a peak at about 20 years of age. Peak BMD has been suggested to explain at least half of the variation in BMD up to old age. Thus, to increase peak BMD could decrease the risk of later fractures. The purpose of the present thesis was to investigate the influence of physical activity, vitamins A and D, and fatty acids on peak bone mass in men.

    The influence of physical activity on bone accrual was studied in two cohorts. In the first cohort 46 ice hockey players, 18 badminton players and 27 controls, all 17 years of age at baseline, were followed for four years. During the follow up the badminton players gained more bone mass at the hip compared to both the ice hockey players and controls. In the second cohort the associations between physical activity and BMD were investigated in 62 female and 62 male young medical students. The estimated high impact activity per week was associated with bone mass at all sites in the male medical students (r=0.27-0.53, p<0.05). In the female cohort different estimates of physical activity were not related to bone mass at any site. In both males and females correlations between bone mass and body constitution parameters were observed.

    Levels of vitamin D3, vitamin D2, retinol, retinol-binding-protein-4 (RBP-4) and fatty acids were measured in 78 young men with a mean age of 22.6 years. BMD at various sites were measured using Dual-Energy X-ray absorptiometry. Levels of vitamin D3 showed a significant positive association with all BMD sites and also lean body mass (r=0.23-0.35, p<0.05). Levels of vitamin D2, however, showed a significant negative correlation with BMD of the total body (r=-0.28, p=0.01) and spine (r=-0.27, p=0.02). There was also a significant negative relationship between levels of vitamin D3 and D2 (r=-0.31, p=0.006). Concentrations of n-3 (omega-3) fatty acids showed a positive association with BMD at the total body (r=0.27, p=0.02) and spine BMD (r=0.25, p=0.02). There was also a positive association between levels of n-3 fatty acids and changes in BMD of the spine between 16 and 22 years of age (r=0.26, p=0.02). The significant associations found seemed to be related mostly to the concentration of the n-3 fatty acid docosahexaenoic acid. Levels of retinol and RBP-4 were not related to BMD but to levels of osteocalcin, which is a marker of bone formation. This association disappeared when adjusting for the influence of abdominal fat mass.

    In summary, the present thesis suggests that many modifiable factors may influence the accumulation of peak bone mass in males, such as physical activity, vitamins, and fatty acids. Further studies are needed to investigate whether optimizing these factors in youth may decrease the risk of osteoporosis later in life.

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  • 295. Ingvar, C.
    et al.
    Ahlgren, J.
    Emdin, Stefan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lofgren, L.
    Nordander, M.
    Nimeus, E.
    Arnesson, L-G
    Long-term outcome of pT1a-b, cN0 breast cancer without axillary dissection or staging: a prospective observational study of 1543 women2020In: British Journal of Surgery, ISSN 0007-1323, E-ISSN 1365-2168Article in journal (Refereed)
    Abstract [en]

    Background: The implementation of screening programmes in Sweden during the mid‐1990s increased the number of small node‐negative breast cancers. In this era before staging by sentinel node biopsy, routine axillary dissection for staging of early breast cancer was questioned owing to the increased morbidity and lack of perceived benefit. The long‐term risk of axillary recurrence when axillary staging is omitted remains unclear.

    Methods: This prospective observational multicentre cohort study included Swedish women diagnosed with breast cancer between 1997 and 2002. The patients had clinically node‐negative, pT1a–b, grade I–II tumours. No axillary staging or dissection was performed. The primary outcome was ipsilateral axillary recurrence and survival.

    Results: A total of 1543 patients were included. Breast‐conserving surgery (BCS) was performed in 94·0 per cent and the rest underwent mastectomy. After surgery, 58·1 per cent of the women received adjuvant radiotherapy, 11·9 per cent adjuvant endocrine therapy and 31·5 per cent did not receive any adjuvant treatment. After a median follow‐up of 15·5 years, 6·4 per cent developed contralateral breast cancer and 16·5 per cent experienced a recurrence. The first recurrence was local in 116, regional in 47 and distant in 59 patients. The breast cancer‐specific survival rate was 93·7 per cent after 15 years. There were no differences in overall or breast cancer‐specific survival between patients who received adjuvant radiotherapy and those who did not. Only 3·0 per cent of patients had an axillary recurrence, which was isolated in only 1·0 per cent.

    Conclusion: Axillary surgery can safely be omitted in patients with low‐grade, T1a–b, cN0 breast cancers. This large prospective cohort with 15‐year follow‐up had a very low incidence of axillary recurrences and high breast cancer‐specific survival rate.

  • 296.
    Iraeus, Johan
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery. ÅF Industry.
    Stochastic finite element simulations of real life frontal crashes: With emphasis on chest injury mechanisms in near-side oblique loading conditions2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Introduction. Road traffic injuries are the eighth leading cause of death globally and the leading cause of death among young people aged 15-29. Of individuals killed or injured in road traffic injuries, a large group comprises occupants sustaining a thorax injury in frontal crashes. The elderly are particularly at risk, as they are more fragile. The evaluation of the frontal crash performance of new vehicles is normally based on barrier crash tests. Such tests are only representative of a small portion of real-life crashes, but it is not feasible to test vehicles in all real-life conditions. However, the rapid development of computers opens up possibilities for simulating whole populations of real-life crashes using so-called stochastic simulations. This opportunity leads to the aim of this thesis, which is to develop and validate a simplified, parameterized, stochastic vehicle simulation model for the evaluation of passive restraint systems in real-life frontal crashes with regard to rib fracture injuries.

    Methods. The work was divided into five phases. In phase one, the geometry and properties of a finite element (FE) generic vehicle buck model were developed based on data from 14 vehicles. In the second phase, a human FE model was validated for oblique frontal crashes. This human FE model was then used to represent the vehicle occupant. In the third phase, vehicle buck boundary conditions were derived based on real-life crash data from the National Automotive Sampling System (NASS) and crash test data from the Insurance Institute for Highway Safety. In phase four, a validation reference was developed by creating risk curves for rib fracture in NASS real-life crashes. Next, these risk curves were compared to the risk of rib fractures computed using the generic vehicle buck model. In the final phase, injury mechanisms in nearside oblique frontal crashes were evaluated.

    Results. In addition to an averaged geometry, parametric distributions for 27 vehicle and boundary condition parameters were developed as guiding properties for the stochastic model. Particular aspects of the boundary conditions such as pulse shape, pulse angle and pulse severity were analyzed in detail. The human FE model validation showed that the kinematics and rib fracture pattern in frontal oblique crashes were acceptable for this study. The validation of the complete FE generic vehicle buck model showed that the model overestimates the risk of rib fractures. However, if the reported under-prediction of rib fractures (50-70%) in the NASS data is accounted for using statistical simulations, the generic vehicle buck model accurately predicts injury risk for senior (70-year-old) occupants. The chest injury mechanisms in nearside oblique frontal crashes were found to be a combination of (I) belt and airbag loading and (II) the chest impacting the side structure. The debut of the second mechanism was found for pulse angles of about 30 degrees.

    Conclusion. A parameterized FE generic passenger vehicle buck model has been created and validated on a population of real life crashes in terms of rib fracture risk. With the current validation status, this model provides the possibility of developing and evaluating new passive safety systems for fragile senior occupants. Further, an injury mechanism responsible for the increased number of outboard rib fractures seen in small overlap and near-side oblique frontal impacts has been proposed and analyzed.

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  • 297.
    Iraeus, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery. ÅF Industry, Göteborg, Sweden.
    Lindquist, Mats
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Development and validation of a generic finite element vehicle buck model for the analysis of driver rib fractures in real life nearside oblique frontal crashes2016In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 95, p. 42-56Article in journal (Refereed)
    Abstract [en]

    Objective: Frontal crashes still account for approximately half of all fatalities in passenger cars, despite several decades of crash-related research. For serious injuries in this crash mode, several authors have listed the thorax as the most important. Computer simulation provides an effective tool to study crashes and evaluate injury mechanisms, and using stochastic input data, whole populations of crashes can be studied. The aim of this study was to develop a generic buck model and to validate this model on a population of real-life frontal crashes in terms of the risk of rib fracture.

    Method: The study was conducted in four phases. In the first phase, real-life validation data were derived by analyzing NASS/CDS data to find the relationship between injury risk and crash parameters. In addition, available statistical distributions for the parameters were collected. In the second phase, a generic parameterized finite element (FE) model of a vehicle interior was developed based on laser scans from the A2MAC1 database. In the third phase, model parameters that could not be found in the literature were estimated using reverse engineering based on NCAP tests. Finally, in the fourth phase, the stochastic FE model was used to simulate a population of real-life crashes, and the result was compared to the validation data from phase one.

    Results: The stochastic FE simulation model overestimates the risk of rib fracture, more for young occupants and less for senior occupants. However, if the effect of underestimation of rib fractures in the NASS/CDS material is accounted for using statistical simulations, the risk of rib fracture based on the stochastic FE model matches the risk based on the NASS/CDS data for senior occupants.

    Conclusion: The current version of the stochastic model can be used to evaluate new safety measures using a population of frontal crashes for senior occupants.

  • 298.
    Iraeus, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery. ÅF Industry, Gothenburg, Sweden.
    Lindquist, Mats
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Influence of Vehicle Kinematic Components on Chest Injury in Frontal-Offset Impacts2014In: Traffic Injury Prevention, ISSN 1538-9588, E-ISSN 1538-957X, Vol. 15, no Supplement 1, p. S88-S95Article in journal (Refereed)
    Abstract [en]

    Objective: Frontal crashes in which the vehicle has poor structural engagement, such as small-overlap and oblique crashes, account for a large number of fatalities. These crash modes are characterized by large intrusion and vehicle yaw rotation. Results from previous studies have shown mixed results regarding the importance and effects of these parameters. The aim of this study was to evaluate how vehicle yaw rotation, instrument panel intrusion, and the time history of the pulse angle influence chest injury outcomes.

    Method: This study was conducted using kinematic boundary conditions derived from physical crash tests, which were applied on a finite element simulation model of a vehicle interior including a finite element human model. By performing simulations with different levels of simplified boundary conditions and comparing the results to a simulation with a full set of boundary conditions, the influence of the simplifications was evaluated. The injury outcome measure compared between the simulations was the expected number of fractured ribs. The 3 simplifications simulated were (1) removal of vehicle yaw rotation, (2) removal of vehicle yaw rotation plus an assumption of a constant pulse angle between the x- and y-acceleration, and (3) removal of instrument panel intrusion.

    The kinematic boundary conditions were collected from 120 physical tests performed at the Insurance Institute of Highway Safety; 77 were small-overlap tests, and 43 were moderate overlap tests. For each test, the full set of boundary conditions plus the 3 simplifications were simulated. Thus, a total of 480 simulations were performed.

    Results: The yaw rotation influences occupant interaction with the frontal airbag. For the approximation without this kinematic boundary component, there was an average error in injury outcome of approximately 13% for the moderate overlap cases. Large instrument panel intrusion increases the risk of rib fracture in nearside small-overlap crashes. The mechanism underlying this increased fracture risk is a combination of increased airbag load and a more severe secondary impact to the side structure. Without the intrusion component, the injury risk was underestimated by 8% for the small-overlap crashes.

    Conclusion: The approximation with least error was version 2; that is, a model assuming a constant pulse angle, including instrument panel intrusion but no vehicle yaw rotation. This approximation simulates a sled test with a buck mounted at an oblique angle. The average error for this approximation was as low as 2–4%.

  • 299.
    Iraeus, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery. ÅF Industry, Gothenburg, Sweden.
    Lindquist, Mats
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Pulse shape analysis and data reduction of real life crashes with modern passenger cars2015In: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 20, no 6, p. 535-546Article in journal (Refereed)
    Abstract [en]

    The increased use of computer simulations such as finite element modelling for evaluating passive safety applications has made it possible to simplify and parameterize complex physical processes. Crash pulses derived from laboratory tests have been used in many studies to evaluate and optimize passive safety systems such as airbags and seat belts. However, a laboratory crash pulse will only be representative of the acceleration time history of a specific car crashing into a barrier at a specified velocity. To be able to optimize passive safety systems for the wide variety of scenarios experienced during real-life crashes, there is a need to study and characterize this variation. In this study, crash pulses from real-life crashes as recorded by event data recorders were parameterized, and the influence of vehicle and crash variables was analysed. The pulse parameterization was carried out using eigenvalue analysis and the influence that vehicle and crash variables had on the pulse shape was determined with multiple linear regression. It was shown that the change in velocity, the subject vehicle mass, and the properties of the collision partner were the variables that had the greatest effect on the shape of the crash pulse. The results of this study can be used to create artificial real-life pulses with different crash parameters. This in turn can be used for stochastic computer simulation studies with the intention of optimizing passive safety systems that are robust to the wide variation in real-life crashes.

  • 300.
    Iraeus, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Lindquist, Mats
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Wistrand, Sofie
    Sibgård, Elin
    Pipkorn, Bengt
    Evaluation of chest injury mechanisms in nearside oblique frontal impacts2013In: Annals of advances in automotive medicine, ISSN 1943-2461, Vol. 57, p. 183-196Article in journal (Refereed)
    Abstract [en]

    Despite the use of seat belts and modern safety systems, many automobile occupants are still seriously injured or killed in car crashes. Common configurations in these crashes are oblique and small overlap frontal impacts that often lead to chest injuries.To evaluate the injury mechanism in these oblique impacts, an investigation was carried out using mathematical human body model simulations. A model of a simplified vehicle interior was developed and validated by means of mechanical sled tests with the Hybrid III dummy. The interior model was then combined with the human body model THUMS and validated by means of mechanical PMHS sled tests. Occupant kinematics as well as rib fracture patterns were predicted with reasonable accuracy.The final model was updated to conform to modern cars and a simulation matrix was run. In this matrix the boundary conditions, ΔV and PDOF, were varied and rib fracture risk as a function of the boundary conditions was evaluated using a statistical framework.In oblique frontal impacts, two injury producing mechanisms were found; (i) diagonal belt load and (ii) side structure impact. The second injury mechanism was found for PDOFs of 25°-35°, depending on ΔV. This means that for larger PDOFs, less ΔV is needed to cause a serious chest injury.

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