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  • 1.
    Ambarki, Khalid
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Israelsson, Hanna
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Wåhlin, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Birgander, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Brain ventricular size in healthy elderly: comparison between evans index and volume measurement.2010Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 67, nr 1, s. 94-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: A precise definition of ventricular enlargement is important in the diagnosis of hydrocephalus as well as in assessing central atrophy. The Evans index (EI), a linear ratio between the maximal frontal horn width and the cranium diameter, has been extensively used as an indirect marker of ventricular volume (VV). With modern imaging techniques, brain volume can be directly measured. OBJECTIVE: To determine reference values of intracranial volumes in healthy elderly individuals and to correlate volumes with the EI. METHODS: Magnetic resonance imaging (3 T) was performed in 46 healthy white elderly subjects (mean age +/- standard deviation, 71 +/- 6 years) and in 20 patients (74 +/- 7 years) with large ventricles according to visual inspection. VV, relative VV (RVV), and EI were assessed. Ventricular dilation was defined using VV and EI by a value above the 95th percentile range for healthy elderly individuals. RESULTS: In healthy elderly subjects, we found VV = 37 +/- 18 mL, RVV = 2.47 +/- 1.17%, and EI = 0.281 +/- 0.027. Including the patients, there was a strong correlation between EI and VV (R = 0.94) as well as between EI and RVV (R = 0.95). However, because of a wide 95% prediction interval (VV: +/-45 mL; RVV: +/- 2.54%), EI did not give a sufficiently good estimate of VV and RVV. CONCLUSION: VV (or RVV) and the EI reflect different properties. The exclusive use of EI in clinical studies as a marker of enlarged ventricles should be questioned. We suggest that the definition of dilated ventricles in white elderly individuals be defined as VV >77 mL or RVV >4.96 %. Future studies should compare intracranial volumes with clinical characteristics and prognosis.

  • 2.
    Asplund, Pär
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Blomstedt, Patric
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Bergenheim, A. Tommy
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Percutaneous Balloon Compression vs Percutaneous Retrogasserian Glycerol Rhizotomy for the Primary Treatment of Trigeminal Neuralgia2016Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 78, nr 3, s. 421-428Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Despite >30 years of clinical use, the literature is still sparse when it comes to comparisons between percutaneous balloon compression (PBC) and percutaneous retrogasserian glycerol rhizolysis (PRGR) as treatments for trigeminal neuralgia.

    OBJECTIVE: To perform a retrospective cohort comparison between PBC and PRGR with regard to therapeutic effect, side effects, and complications.

    METHODS: Medical records and follow-up data from 124 primary PRGRs performed from 1986 to 2000 and 82 primary PBCs performed from 2000 to 2013 were reviewed. All patients had undergone clinical sensory testing and assessment of sensory thresholds. Analyses were performed to compare duration of pain relief, frequency of sensory disturbances, and side effects.

    RESULTS: Median duration of pain relief was 21 months after PRGR and 20 months after PBC. Both methods carried a high risk of hypesthesia/hypalgesia (P < .001) that was partly reversed with time. Decreased corneal sensibility was common after PRGR (P < .001) but not after PBC. Dysesthesia was more common after PRGR (23%) compared after PBC (4%; P < .001). Other side effects were noted but uncommon.

    CONCLUSION: PBC and PRGR are both effective as primary surgical treatment of trigeminal neuralgia. Both carry a risk of postoperative hypesthesia, but in this series, the side effect profile favored PBC. Furthermore, PBC is technically less challenging, whereas PRGR requires fewer resources. Between these 2 techniques, we propose PBC as the primary surgical technique for percutaneous treatment of trigeminal neuralgia on the basis of its lower incidence of dysesthesia, corneal hypesthesia, and technical failures.

    ABBREVIATIONS: MS, multiple sclerosisPBC, percutaneous balloon compressionPRGR, percutaneous retrogasserian glycerol rhizotomyTN, trigeminal neuralgiaThis is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work, provided it is properly cited. The work cannot be changed in any way or used commercially.

  • 3. Behrens, Anders
    et al.
    Lenfeldt, Niklas
    Ambarki, Khalid
    Malm, Jan
    Eklund, Anders
    Koskinen, Lars-Owe
    In Reply2010Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 67, nr 6, s. 1864-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 4.
    Behrens, Anders
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Lenfeldt, Niklas
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Ambarki, Khalid
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Koskinen, Lars-Owe
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Transcranial Doppler pulsatility index: not an accurate method to assess intracranial pressure.2010Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 66, nr 6, s. 1050-1057Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Transcranial Doppler sonography (TCD) assessment of intracranial blood flow velocity has been suggested to accurately determine intracranial pressure (ICP). OBJECTIVE: We attempted to validate this method in patients with communicating cerebrospinal fluid systems using predetermined pressure levels. METHODS: Ten patients underwent a lumbar infusion test, applying 4 to 5 preset ICP levels. On each level, the pulsatility index (PI) in the middle cerebral artery was determined by measuring the blood flow velocity using TCD. ICP was simultaneously measured with an intraparenchymal sensor. ICP and PI were compared using correlation analysis. For further understanding of the ICP-PI relationship, a mathematical model of the intracranial dynamics was simulated using a computer. RESULTS: The ICP-PI regression equation was based on data from 8 patients. For 2 patients, no audible Doppler signal was obtained. The equation was ICP = 23*PI + 14 (R = 0.22, P < .01, N = 35). The 95% confidence interval for a mean ICP of 20 mm Hg was -3.8 to 43.8 mm Hg. Individually, the regression coefficients varied from 42 to 90 and the offsets from -32 to +3. The mathematical simulations suggest that variations in vessel compliance, autoregulation, and arterial pressure have a serious effect on the ICP-PI relationship. CONCLUSIONS: The in vivo results show that PI is not a reliable predictor of ICP. Mathematical simulations indicate that this is caused by variations in physiological parameters.

  • 5.
    Behrens, Anders
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Lenfeldt, Niklas
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Ambarki, Khalid
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Koskinen, Lars-Owe D
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Intracranial Pressure and Pulsatility Index:  2011Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 69, nr 4, s. E1033-E1034Artikel i tidskrift (Refereegranskat)
  • 6.
    Blomstedt, Patric
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Olivecrona, Magnus
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Sailer, Alexandra
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurofysiologi.
    Hariz, Marwan I
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Dittmar and the history of stereotaxy: or rats, rabbits, and references2007Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 60, nr 1, s. 198-201Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    The renaissance of stereotactic functional neurosurgery has resulted in increased interest in its origins. Twenty articles concerning this field trace the history back to a paper published in 1873 by Dittmar: “Über die Lage des sogenannten Gefaesszentrums in der Medulla oblongata” [On the location of the so-called vasomotor center in the medulla oblongata]. Few facts are presented. But, taken together, the impression given by the secondary sources is that Dittmar, in 1873, presented a guiding device for localization of intracranial structures for the positioning of electrodes/blades in the medulla oblongata in rats. Of the publications that cite Dittmar's original article as their only quoted source, half did not specify the inserted object and the animal of the experiment. The remaining articles reported either that the introduced object was an electrode or that the experiments were performed on rats. Dittmar's original article, however, did not report use of his apparatus for insertion of electrodes, nor did he use rats. All experiments were performed by making incisions in the medulla oblongata in rabbits. Dittmar's apparatus was constructed to allow more precision when performing incisions in the medulla oblongata than could be obtained performing incisions freehand. The incision point was chosen and the blade introduced with direct visual guidance. This has been described as “spatial localization of intracranial structures,” “a special targeting instrument,” or simply, “a guiding device.” In our opinion, it can most properly be classified as a supportive arm.

  • 7.
    Blomstedt, Patric
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Sandvik, Ulrika
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Fytagoridis, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Tisch, Stephen
    Department of Neurology, St Vincent's Hospital, University of New South Wales, Sydney, Australia.
    The posterior subthalamic area in the treatment of movement disorders: past, present, and future2009Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 64, nr 6, s. 1029-1038Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The introduction of thalamotomy in 1954 led naturally to exploration of the underlying subthalamic area, with the development of such procedures as campotomy and subthalamotomy in the posterior subthalamic area. The most popular of these procedures was the subthalamotomy, which was performed in thousands of patients for various movement disorders. Today, in the deep brain stimulation (DBS) era, subthalamic nucleus DBS is the treatment of choice for Parkinson's disease, whereas thalamic and pallidal DBS are mainly used for nonparkinsonian tremor and dystonia, respectively. The interest in DBS in the posterior subthalamic area has been quite limited, however, with a total of 95 patients presented in 14 articles. During recent years, interest has increased, and promising results have been published concerning both Parkinson's disease and nonparkinsonian tremor. We reviewed the literature to investigate the development of surgery in the posterior subthalamic area from the lesional era to the present.

  • 8. Holl, Etienne M
    et al.
    Petersen, Erika A
    Foltynie, Thomas
    Martinez-Torres, Irene
    Limousin, Patricia
    Hariz, Marwan I
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Zrinzo, Ludvic
    Improving targeting in image-guided frame-based deep brain stimulation2010Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 67, nr 2 Suppl, s. ons437-ons447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    After calibration of a systematic targeting error an MR image-guided stereotactic approach would be expected to deliver 97% of all electrodes to within 2 mm of the intended target point with a single brain pass.

  • 9.
    Israelsson, Hanna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Allard, Per
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Psykiatri.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Symptoms of Depression are Common in Patients With Idiopathic Normal Pressure Hydrocephalus: The INPH-CRasH Study2016Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 78, nr 2, s. 161-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: If patients with idiopathic normal pressure hydrocephalus (INPH) also have depression, this could have important clinical ramifications in assessment and management of their cognitive function and response to shunting. In many dementias, depression is overrepresented, but the prevalence of depression in shunted patients with INPH is unknown.

    OBJECTIVE: The objective of this case-control study was to assess the prevalence of symptoms of depression in shunted INPH patients compared with population-based controls.

    METHODS: INPH patients consecutively shunted from 2008 to 2010 in Sweden were analyzed. Patients remaining after inclusion (within 60-85 years and not having dementia, ie, mini-mental state examination >=23) had a standardized visit to their healthcare provider and answered an extensive questionnaire. Age- and sex-matched population-based controls underwent the same procedure. Symptoms of depression were assessed using the Geriatric Depression Scale 15 (suspected depression defined as >=5 points, suspected severe depression as >=12 points). This study is part of the INPH-CRasH study.

    RESULTS: One hundred seventy-six INPH patients and 368 controls participated. After adjustment for age, sex, cerebrovascular disease, and systolic and diastolic blood pressure, patients had a higher mean depression score (patients: 4.9 ± 3.7 SD, controls: 1.9 ± 2.3 SD; OR 1.4, 95% CI 1.3-1.6, P < .001), more patients had suspected depression (46% vs 13%, OR 6.4, 95% CI 3.8-10.9, P < .001), and more patients had suspected severe depression (7.3% vs 0.6%, OR 14.4, 95% CI 3.0-68.6, P < .005).

    CONCLUSION: Symptoms of depression are overrepresented in INPH patients compared with the population, despite treatment with a shunt. Screening for depression should be done in the evaluation of INPH patients in order to find and treat a coexisting depression.

  • 10.
    Koskinen, Lars-Owe D
    et al.
    Umeå universitet, Medicinsk fakultet, Farmakologi och klinisk neurovetenskap, Neurokirurgi. Neurokirurgi.
    Olivecrona, Magnus
    Umeå universitet, Medicinsk fakultet, Farmakologi och klinisk neurovetenskap, Neurokirurgi. Neurokirurgi.
    Clinical experience with the intraparenchymal intracranial pressure monitoring Codman MicroSensor system.2005Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 56, nr 4, s. 693-698Artikel i tidskrift (Refereegranskat)
  • 11.
    Koskinen, Lars-Owe D
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Olivecrona, Magnus
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Intracranial pressure monitoring using the Codman MicroSensor2010Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 67, nr 1, s. 221-Artikel i tidskrift (Övrigt vetenskapligt)
  • 12.
    Lenfeldt, Niklas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF). Neurologi.
    Hauksson, Jón
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Birgander, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Eklund, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap. Neurologi.
    Improvement after cerebrospinal fluid drainage is related to levels of N-acetyl-aspartate in idiopathic normal pressure hydrocephalus2008Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 62, nr 1, s. 135-142Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    OBJECTIVE: This study uses proton magnetic resonance spectroscopy to investigate whether or not idiopathic normal pressure hydrocephalus is associated with neuronal dysfunction or ischemia in the brain. We evaluate whether or not proton magnetic resonance spectroscopy is useful for predicting improvement after long-term external lumbar drainage (ELD) of cerebrospinal fluid.

    METHODS: Eighteen patients (mean age, 73 yr; six women) and 10 matching controls participated. Participants were characterized by clinical features, cognitive and motor function tests, and cerebrospinal fluid hydrodynamics (patients only). Signals from N-acetyl-aspartate (NAA), choline, lactate, and creatine (Cr) (reference) were sampled once in controls and twice in patients (before and after a 3-day ELD of approximately 135 mL/24 h) by proton magnetic resonance spectroscopy (1.5 T) from a 7.2-mL volume in the frontal white matter. Improvement was defined by video recordings of the patients' gait.

    RESULTS: Sixteen patients finished the ELD (one patient had meningitis, and one patient had catheter insertion failure) with a mean drain volume of 395 mL. NAA/Cr ratios were lower in patients than in controls (1.60 versus 1.84, P = 0.02), but no difference was found for choline/Cr ratios. No lactate signals were detected. Fifty percent of patients improved after ELD. They had higher NAA/Cr ratios than nonimproved patients (1.70 versus 1.51, P = 0.01), but no differences were found in choline/Cr ratios or drain volume.

    CONCLUSION: NAA/Cr ratios were decreased in patients with idiopathic normal pressure hydrocephalus, which is consistent with neuronal dysfunction in the frontal white matter. Improved patients had NAA/Cr ratios close to normal, indicating that enough functional neurons are a prerequisite for the cerebrospinal fluid drainage to have an effect.

  • 13.
    Lenfeldt, Niklas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Larsson, Anne
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi.
    Birgander, Richard
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Eklund, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Diffusion tensor imaging reveals supplementary lesions to frontal white matter in Idiopathic normal pressure hydrocephalus2011Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 68, nr 6, s. 1586-1593Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND:: Idiopathic normal pressure hydrocephalus (INPH) is associated with white matter lesions, but the extent and severity of the lesions do not cohere with symptoms or improvement after shunting, implying the presence of further, yet undisclosed, injuries to white matter in INPH. OBJECTIVE:: To apply diffusion tensor imaging (DTI) to explore white matter lesions in patients with INPH before and after drainage of cerebrospinal fluid (CSF). METHODS:: Eighteen patients and ten controls were included. DTI was performed in a 1.5T MRI scanner before and after three-day drainage of 400 ml of CSF. Regions of interest included corpus callosum, capsula interna, frontal and lateral periventricular white matter, and centrum semiovale. White matter integrity was quantified by assessing fractional anisotropies (FA) and apparent diffusion coefficients (ADC), comparing them between patients and controls and between patients before and after drainage. The significance level corresponded to 0.05 (Bonferroni corrected). RESULTS:: Decreased FA in patients was found in three regions (p<0.002, p<0.001 and p<0.0001) in anterior frontal white matter, whereas elevated ADC was found in genu corpus callosum (p<0.0001) and areas of centrum semiovale associated to the precentral gyri (p<0.002). Diffusion patterns in these areas did not change after drainage. CONCLUSION:: DTI reveals subtle injuries - interpreted as axonal loss and gliosis - to anterior frontal white matter where high-order motor systems between frontal cortex and basal ganglia travel, further supporting the notion that motor symptoms in INPH are caused by a chronic ischemia to the neuronal systems involved in the planning processes of movements.

  • 14.
    Lindvall, Peter
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Bergström, P
    Löfroth, PO
    Hariz, MI
    Henriksson, R
    Jonasson, P
    Bergenheim, AT
    Hypofractionated conformal stereotactic radiotherapy for arteriovenous malformations2003Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 53, nr 5, s. 1036-1042Artikel i tidskrift (Refereegranskat)
  • 15. Petersen, Erika A
    et al.
    Holl, Etienne M
    Martinez-Torres, Irene
    Foltynie, Thomas
    Limousin, Patricia
    Hariz, Marwan I
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Zrinzo, Ludvic
    Minimizing brain shift in stereotactic functional neurosurgery2010Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 67, nr 3 Suppl, s. ons213-ons221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Brain shift has long been considered an issue in stereotactic targeting during DBS procedures. However, with the image-guided approach and surgical technique used in this study, subcortical brain shift was extremely limited and did not appear to adversely affect clinical outcome.

  • 16.
    Sandvik, Ulrika
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Koskinen, Lars-Owe
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Lundquist, Anders
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Blomstedt, Patric
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Thalamic and subthalamic DBS for essential tremor: where is the optimal target?2012Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 70, nr 4, s. 840-846Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The ventrolateral thalamus (Vim, ventral intermediate nucleus) is the traditional target for neurosurgical treatment of essential tremor (ET). The target has, however, varied substantially among different neurosurgeons.

    Objective: To evaluate the effect of deep brain stimulation (DBS) in the thalamus and posterior subthalamic area (PSA) in relation to electrode location.

    Methods: 36 (17Vim / 19 PSA) patients, with 44 DBS electrodes, were included in this retrospective study. The effect of stimulation was evaluated with standardized settings for each contact using items from the essential tremor rating scale (ETRS).

    Results: When each contact was evaluated regarding the treated hand with standardized stimulation, the electrode contact providing the best effect in the individual patient was in 54% located in the zona incerta (Zi) or radiation prelemniscalis (raprl) and in 12 % the Vim. 40 contacts provided a tremor reduction of >90%. Of these, 43% were located in the PSA and 18% in the Vim according to the Schaltenbrandt atlas. 37 of these 40 contacts were found in the PSA group.

    Conclusion: More contacts yielding an optimal effect were found in the PSA group than in the Vim. Many patients operated upon in the Vim got the best effect in a contact located in the PSA. This might suggest that the PSA is a more efficient target than the Vim.

  • 17.
    Sandvik, Ulrika
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Koskinen, Lars-Owe
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Lundquist, Anders
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Blomstedt, Patric
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurokirurgi.
    Thalamic and subthalamic deep brain stimulation for essential tremor: where is the optimal target?2012Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 70, nr 4, s. 840-845Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: The ventrolateral thalamus (ventral intermediate nucleus [ Vim]) is the traditional target for neurosurgical treatment of essential tremor. The target, however, has varied substantially among different neurosurgeons.

    OBJECTIVE: To evaluate the effect of deep brain stimulation in the thalamus and posterior subthalamic area (PSA) in relation to electrode location.

    METHODS: Thirty-six (17 Vim/19 PSA) patients with 44 deep brain stimulation electrodes were included in this retrospective study. The effect of stimulation was evaluated with standardized settings for each contact using items from the Essential Tremor Rating Scale.

    RESULTS: When each contact was evaluated in terms of the treated hand with standardized stimulation, the electrode contact providing the best effect in the individual patient was located in the zona incerta or radiation prelemniscalis in 54% and the Vim in 12%. Forty contacts provided a tremor reduction of > 90%. Of these, 43% were located in the PSA and 18% in the Vim according to the Schaltenbrand atlas. Of these 40 contacts, 37 were found in the PSA group.

    CONCLUSION: More contacts yielding an optimal effect were found in the PSA group than in the Vim. Many patients operated on in the Vim got the best effect from a contact located in the PSA. This might suggest that the PSA is a more efficient target than the Vim.

  • 18.
    West, Christian Alexander
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Ljungberg, Christina
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Wiberg, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Hart, Andrew
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi. Plastic Surgery Research, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom, Canniesburn Plastic Surgery Unit, Scottish National Brachial Plexus Service, Glasgow Royal Infirmary, Glasgow, United Kingdom.
    Sensory neuron death after upper limb nerve injury and protective effect of repair: clinical evaluation using volumetric magnetic resonance imaging of dorsal root Ganglia.2013Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 73, nr 4, s. 632-640Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Extensive death of sensory neurons after nerve trauma depletes the number of regenerating neurons, contributing to inadequate cutaneous innervation density and poor sensory recovery. Experimentally proven neuroprotective neoadjuvant drugs require noninvasive in vivo measures of neuron death to permit clinical trials. In animal models of nerve transection, magnetic resonance imaging (MRI) proved a valid tool for quantifying sensory neuron loss within dorsal root ganglia (DRG) by measuring consequent proportional shrinkage of respective ganglia.

    OBJECTIVE: This system is investigated for clinical application after upper limb nerve injury and microsurgical nerve repair.

    METHODS: A 3-T clinical magnet was used to image and measure volume (Cavalieri principle) of C7-T1 DRG in uninjured volunteers (controls, n = 14), hand amputees (unrepaired nerve injury, n = 5), and early nerve repair patients (median and ulnar nerves transected, microsurgical nerve repair within 24 hours, n = 4).

    RESULTS: MRI was well tolerated. Volumetric analysis was feasible in 74% of patients. A mean 14% volume reduction was found in amputees' C7 and C8 DRG (P < .001 vs controls). Volume loss was lower in median and ulnar nerve repair patients (mean 3% volume loss, P < .01 vs amputees), and varied among patients. T1 DRG volume remained unaffected.

    CONCLUSION: MRI provides noninvasive in vivo assessment of DRG volume as a proxy clinical measure of sensory neuron death. The significant decrease found after unrepaired nerve injury provides indirect clinical evidence of axotomy-induced neuronal death. This loss was less after nerve repair, indicating a neuroprotective benefit of early repair. Volumetric MRI has potential diagnostic applications and is a quantitative tool for clinical trials of neuroprotective therapies.

  • 19.
    West, Christian Alexander
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    McKay Hart, Andrew
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi.
    Terenghi, Giorgio
    Manchester University.
    Wiberg, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Anatomi. Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Handkirurgi.
    Sensory Neurons of the Human Brachial Plexus: A Quantitative Study Employing Optical Fractionation and In-Vivo Volumetric Magnetic Resonance Imaging.2012Ingår i: Neurosurgery, ISSN 0148-396X, E-ISSN 1524-4040, Vol. 70, nr 5, s. 1183-1194Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Extensive neuron death following peripheral nerve trauma is implicated in poor sensory recovery. Translational research for experimentally proven neuroprotective drugs requires knowledge of the numbers and distribution of sensory neurons in the human upper limb, and a novel non-invasive clinical measure of neuron loss. OBJECTIVE: To compare optical fractionation and volumetric MRI of dorsal root ganglia (DRG) in histological quantification and objective clinical assessment of human brachial plexus sensory neurons. METHODS: Bilateral C5-T1 DRG were harvested from 5 human cadavers for stereological volume measurement and sensory neuron counts (optical fractionator). MRI scans were obtained from 14 normal volunteers for volumetric analysis of C5-T1 DRG. RESULTS: 425,409 (SD 15,596) sensory neurons innervate the brachial plexus with a significant difference in neuron counts and DRG volume between segmental levels (p<0.0001), with C7 ganglion containing the most. DRG volume correlated with neuron counts (r=0.75, p<.001). Vertebral artery pulsation hindered C5&6 imaging, yet high resolution MRI of C7, C8 and T1 DRG permitted unbiased volume measurement. In accord with histological analysis, MRI confirmed a significant difference between C7, C8 and T1 DRG volume (p<.001), inter-individual variability (COV 15.3%), and sex differences (p=.04). Slight right-left (R/L) sided disparity in neuron counts (2.5%, p=.04) was possibly related to hand dominance, but no significant volume disparity existed. CONCLUSION: Neuron counts for the human brachial plexus are presented. These correlate with histological DRG volumes and concur with volumetric MRI results in human volunteers. Volumetric MRI of C7-T1 DRG is a legitimate non-invasive proxy measure of sensory neurons for clinical study.

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