umu.sePublications
Change search
Refine search result
1 - 26 of 26
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Abosch, Aviva
    et al.
    Timmermann, Lars
    Bartley, Sylvia
    Rietkerk, Hans Guido
    Whiting, Donald
    Connolly, Patrick J.
    Lanctin, David
    Hariz, Marwan I.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    An International Survey of Deep Brain Stimulation Procedural Steps2013In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 91, no 1, p. 1-11Article, review/survey (Refereed)
    Abstract [en]

    Background: Deep brain stimulation (DBS) surgery is standard of care for the treatment of certain movement disorders.

    Objective: We sought to characterize the spectrum of steps performed in DBS surgery, at centers around the world where this surgery is performed.

    Methods: We identified the main steps in DBS surgery workflow and grouped these 19 steps into 3 phases (preoperative, operative, and postoperative). A survey tool, informed by a pilot survey, was administered internationally by trained study personnel at high- and low-volume DBS centers. Procedural components, duration, and surgeon motivational factors were assessed. Cluster analysis was used to identify procedural and behavioral clusters.

    Results: One hundred eighty-five procedure workflow surveys (143 DBS centers) and 65 online surveys of surgeon motivational drivers were completed (45% response rate). Significant heterogeneity in technique, operative time, and surgeon motivational drivers was reported across centers.

    Conclusions: We provide a description of the procedural steps involved in DBS surgery and the duration of these steps, based on an international survey. These data will enable individual surgeons and centers to examine their own experience relative to colleagues at other centers and in other countries. Such information could also be useful in comparing efficiencies and identifying workflow obstacles between different hospital environments.

  • 2. Akram, Harith
    et al.
    Limousin, Patricia
    Hyam, Jonathan
    Hariz, Marwan I.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London.
    Zrinzo, Ludvic
    Aim for the Suprasternal Notch: Technical Note to Avoid Bowstringing after Deep Brain Stimulation2015In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 93, no 4, p. 227-230Article in journal (Refereed)
    Abstract [en]

    Background: Bowstringing may occur when excessive fibrosis develops around extension cables in the neck after deep brain stimulation (DBS) surgery. Though the occurrence of this phenomenon is rare, we have noted that it tends to cause maximal discomfort when the cables cross superficially over the convexity of the clavicle. We hypothesise that bowstringing may be avoided by directing the extension cables towards the suprasternal notch. Methods: When connecting DBS leads to an infraclavicular pectoral implantable pulse generator (IPG), tunnelling is directed towards the suprasternal I notch, before being directed laterally towards the IPG pocket. In previously operated patients with established fibrosis, the fibrous tunnel is opened and excised as far cranially as possible, allowing medial rerouting of cables. Using this approach, we reviewed our series of patients who underwent DBS surgery over 10 years. Results: In 429 patients, 7 patients (2%) with cables tunnelled over the convexity of the clavicle complaining of bowstringing underwent cable exploration and rerouting. This eliminated bowstringing and provided better cosmetic results. When the cable trajectory was initially directed towards the suprasternal notch, no bowstringing was observed. Conclusion:The tunnelling trajectory appears to influence postoperative incidence of fibrosis associated with DBS cables. Modifying the surgical technique may reduce the incidence of this troublesome adverse event. (C) 2015 S.Karger AG, Basel

  • 3.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    When the head is too big for the frame2014In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 92, no 4, p. 264-264Article in journal (Refereed)
  • 4.
    Blomstedt, Patric
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Bjartmarz, Hjalmar
    Intracerebral infections as a complication of deep brain stimulation2012In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 90, no 2, p. 92-96Article in journal (Refereed)
    Abstract [en]

    Background: Intracerebral infections after deep brain stimulation (DBS) are rare. The published material is limited to 2 case reports. A review of 20 publications of 3,818 patients focusing on complications of DBS did not reveal one single case. For that reason, we decided to present our own experience of 4 patients with this complication.

    Objectives: To analyze and present our material regarding intracerebral infections after DBS.

    Methods: Four patients with intracerebral infection after DBS were retrospectively analyzed. Results: The 4 patients exhibited signs of intracerebral infection 2-14 days after DBS for Parkinson's disease. CT and MRI verified signs of possible cerebral involvement. In 3 patients, positive cultures were obtained from the extracted electrodes. All patients recovered completely following treatment with antibiotics and removal of the implanted hardware. Two of the patients were later re-implanted.

    Conclusions: Intracerebral infection is a rare complication of DBS. It does, however, occur occasionally and should be taken into consideration when evaluating the risks of DBS.

    Copyright (c) 2012 S. Karger AG, Basel

  • 5.
    Blomstedt, Patric
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Hariz, Marwan I
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Are complications less common in deep brain stimulation than in ablative procedures for movement disorders?2006In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 84, no 2-3, p. 72-81Article in journal (Refereed)
    Abstract [en]

    The side effects and complications of deep brain stimulation (DBS) and ablative lesions for tremor and Parkinson’s disease were recorded in 256 procedures (129 DBS and 127 lesions). Perioperative complications (seizures, haemorrhage, confusion) were rare and did not differ between the two groups. The rate of hardware-related complications was 17.8%. In ventral intermediate (Vim) thalamotomies, the rate of side effects was 74.5%, in unilateral Vim-DBS 47.3%, while in 7 bilateral Vim-DBS 13 side effects occurred. Most of the side effects of Vim-DBS were reversible upon switching off, or altering, stimulation parameters. In unilateral pallidotomy, the frequency of side effects was 21.9%, while in bilateral staged pallidotomies it was 33.3%. Eight side effects occurred in 11 procedures with pallidal DBS. In 22 subthalamic nucleus DBS procedures, 23 side effects occurred, of which 8 were psychiatric or cognitive. Unilateral ablative surgery may not harbour more postoperative complications or side effects than DBS. Some of the side effects following lesioning are transient and most but not all DBS side effects are reversible. In the Vim DBS is safer than lesioning, while in the pallidum, unilateral lesions are well tolerated.

    Copyright © 2006 S. Karger AG, Basel

  • 6.
    Fytagoridis, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Complications and side effects of deep brain stimulation in the posterior subthalamic area.2010In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 88, no 2, p. 88-93Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The posterior subthalamic area (PSA), including the zona incerta and prelemniscal radiation (Raprl), has recently been presented in number of publications as a promising target for deep brain stimulation (DBS) in the treatment of various movement disorders. In order to evaluate the safety of the procedure, we analyzed our initial 40 patients for complications and side effects. METHODS: 40 patients treated with PSA DBS for Parkinson's disease, essential tremor and other forms of tremor were included. RESULTS: The most severe complication was 1 transient mild hemiparesis and 1 infection. Minor complications and side effects were relatively frequent, including mild transient dysphasia in 22.5% of the patients. CONCLUSIONS: Few serious complications were encountered, and we consider the PSA to be a safe target for DBS.

  • 7.
    Fytagoridis, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Neurosurgery, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm. Asia-Pacific Centre for Neuromodulation, Queensland Brain Institute, University of Queensland.
    Heard, Tomas
    Samuelsson, Jennifer
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Department of Neurosurgery, Sahlgrenska University Hospital, Göteborg.
    Zsigmond, Peter
    Jiltsova, Elena
    Skyrman, Simon
    Skoglund, Thomas
    Coyne, Terry
    Silburn, Peter
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Surgical Replacement of Implantable Pulse Generator in Deep Brain Stimulation: Adverse Events and Risk Factors in a Multicenter Cohort2016In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 94, no 4, p. 235-239Article in journal (Refereed)
    Abstract [en]

    Background: Deep brain stimulation (DBS) is a growing treatment modality, and most DBS systems require replacement of the implantable pulse generator (IPG) every few years. The literature regarding the potential impact of adverse events of IPG replacement on the longevity of DBS treatments is rather scarce. Objective: To investigate the incidence of adverse events, including postoperative infections, associated with IPG replacements in a multicenter cohort. Methods: The medical records of 808 patients from one Australian and five Swedish DBS centers with a total of 1,293 IPG replacements were audited. A logistic regression model was used to ascertain the influence of possible predictors on the incidence of adverse events. Results: The overall incidence of major infections was 2.3% per procedure, 3.7% per patient and 1.7% per replaced IPG. For 28 of 30 patients this resulted in partial or complete DBS system removal. There was an increased risk of infection for males (OR 3.6, p = 0.026), and the risk of infection increased with the number of prior IPG replacements (OR 1.6, p < 0.005). Conclusions: The risk of postoperative infection with DBS IPG replacement increases with the number of previous procedures. There is a need to reduce the frequency of IPG replacements. 

  • 8.
    Fytagoridis, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Sjöberg, Richard
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Åström, Mattias
    Fredricks, Anna
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Effects of deep brain stimulation in the caudal Zona incerta on verbal fluency2013In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 91, no 1, p. 24-29Article in journal (Refereed)
    Abstract [en]

    Background: Deep brain stimulation (DBS) of the caudal zona incerta (cZi) is a relatively unexplored and promising treatment in patients with severe essential tremor (ET). Preliminary data further indicate that the ability to produce language may be slightly affected by the treatment.

    Objective: To evaluate the effects on verbal fluency following cZi DBS in patients with ET.

    Method: Seventeen consecutive patients who had undergone DBS of the cZi for ET were tested regarding verbal fluency before surgery, 3 days after surgery and after 1 year. Ten patients were also evaluated by comparing performance on versus off stimulation after 1 year.

    Results: The total verbal fluency score decreased slightly, but significantly, from 22.7 (SD = 10.9) before surgery to 18.1 (SD = 7.5) 3 days after surgery (p = 0.036). After 1 year the score was nonsignificantly decreased to 20.1 (SD = 9.7, p = 0.2678). There was no detectable difference between stimulation on and off after 1 year.

    Conclusion: There was a tendency of an immediate and mostly transient postoperative decline in verbal fluency following cZi DBS for ET. In some of the patients this reduction was, however, more pronounced and also sustained over time.

  • 9.
    Fytagoridis, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Department of Clinical Neuroscience, Neurosurgery, Karolinska Institutet, Stockholm.
    Åström, Mattias
    Samuelsson, Jennifer
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Deep Brain Stimulation of the Caudal Zona Incerta: Tremor Control in Relation to the Location of Stimulation Fields2016In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 94, no 6, p. 363-370Article in journal (Refereed)
    Abstract [en]

    Background: The caudal zona incerta (cZi) and posterior subthalamic area (PSA) are an emerging deep brain stimulation (DBS) target for essential tremor (ET). Objectives: To evaluate the efficacy of tremor control in relation to the anatomical locations of stimulation fields in 50 patients with ET and DBS of the cZi. Methods: A total of 240 contacts were evaluated separately with monopolar stimulation, and amplitudes were optimized for improvement of tremor and hand function. Stimulation fields, i.e., volumes of neural activation, were simulated for each optimized setting and assembled into probabilistic stimulation maps (PSMs). Results: There were differences in the anatomical distribution of PSMs associated with good versus poor tremor control. The location of PSMs which achieved good and excellent tremor control corresponded well with the PSM for the clinically used settings, and they were located within the superior part of the PSA. Conclusions: PSMs may serve as a useful tool for defining the most efficacious anatomical location of stimulation. The best tremor control in this series of cZi DBS was achieved with stimulation of the superior part of the PSA, which corresponds to the final part of the cerebellothalamic projections before they reach the ventral lateral thalamus.

  • 10. Hamel, Wolfgang
    et al.
    Koeppen, Johannes A.
    Hariz, Marwan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. nit of Functional Neurosurgery, UCL Institute of Neurology, London, UK.
    Krack, Paul
    Moll, Christian K. E.
    The Pioneering and Unknown Stereotactic Approach of Roeder and Orthner from Gottingen. Part I. Surgical Technique for Tailoring Individualized Stereotactic Lesions2016In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 94, no 4, p. 240-253Article in journal (Refereed)
    Abstract [en]

    During the 1950s through the 1970s, Hans Orthner and Fritz Roeder, two German neurologists from Gottingen, developed a sophisticated technique to perform functional stereotactic surgery with outstanding accuracy. They introduced direct air ventriculography performed in the same surgical session as the ablative stereotactic procedure. For individualized surgical targeting, Orthner prepared a stereo tactic atlas (>60 brains) with an ingenious brain-slicing device, the Gottinger macrotome. Brains were grouped based on similarity of six different head and ventricle measurements. A brain cluster representing the best match for a patient was selected for stereotactic targeting. Stereotactic lesions were tailored in an individual manner and shaped by stringing together multiple small coagulations following in-traoperative test stimulation. This was achieved from a single probe trajectory by using well-engineered string electrodes with calibrated curving and involved laborious calculations. Only high-frequency thermocoagulation was regarded as appropriate for lesioning. With this meticulous technique, the most advanced stereotactic procedures were performed, including bilateral pallidotomy that ultimately could be restricted to the ansa lenticularis and ventromedial hypothalamotomy, the most delicate stereotactic operation performed to date. Outside Gottingen, this technique has only been used by Prof. Dieter Muller in Hamburg, Germany. This elaborate stereotactic approach is widely unknown and deserves to be discussed in a historical context. 

  • 11. Hamel, Wolfgang
    et al.
    Koeppen, Johannes A.
    Mueller, Dieter
    Hariz, Marwan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. Unit of Functional Neurosurgery, UCL Institute of Neurology, London, UK.
    Moll, Christian K. E.
    Krack, Paul
    The Pioneering and Unknown Stereotactic Approach of Roeder and Orthner from Gottingen. Part II: Long-Term Outcome and Postmortem Analysis of Bilateral Pallidotomy in the Pre-Levodopa Era2018In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 96, no 6, p. 353-363Article, review/survey (Refereed)
    Abstract [en]

    Before the advent of levodopa, pallidotomy was initially the most effective treatment for Parkinson disease, but it was soon superseded by thalamotomy. It is widely unknown that, similar to Leksell, 2 neurologists from Gottingen, Orthner and Roeder, perpetuated pallidotomy against the mainstream of their time. Postmortem studies demonstrated that true posterior and ventral pallidoansotomy sparing the overwhelming mass of the pallidum was accomplished. This was due to a unique and individually tailored stereotactic technique even allowing bilateral staged pallidotomies. In 1962, the long-term effects (3-year follow-up on average) of the first 18 out of 36 patients with staged bilateral pallidotomies were reported in great detail. Meticulous descriptions of each case indicate long-term improvements in parkinsonian rigidity and associated pain, as well as posture, gait, and akinesia (e.g., improved repetitive movements and arm swinging). Alleviation of tremor was found to require larger lesions than needed for suppression of rigidity. No improvement in speech, drooling, or seborrhea was observed. By 1962, the team had operated 13 patients with postencephalitic oculogyric crises with remarkable results (mean follow-up: 5 years). They also described alleviation of nonparkinsonian hyperkinetic disorders (e.g., hemiballism and chorea) with pallidotomy. The reported rates for surgical mortality and other complications had been remarkably low, even if compared to those reported after the revival of pallidotomy by Laitinen in the post-levodopa era. This applies also to bilateral pallidotomy performed with a positive risk-benefit ratio that has remained unparalleled to date. The intricate history of pallidotomy for movement disorders is incomplete without an appreciation of the achievements of the Gottingen group.

  • 12.
    Hariz, Marwan I
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Hirabayashi, Hidehiro
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Is there a relationship between size and site of the stereotactic lesion and symptomatic results of pallidotomy and thalamotomy?1997In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 69, no 1-4, p. 28-45Article in journal (Refereed)
    Abstract [en]

    Forty-six patients who had 50 stereotactic procedures (36 pallidotomies and 14 thalamotomies) were assessed clinically with regard to akinesia, tremor, dyskinesias and dystonias, and underwent a stereotactic imaging study 6 months after surgery. The surgical results were rated as excellent, good/fair or no change, respectively, for each symptom, and were correlated to the volume and location of the stereotactic lesion. The effect of pallidotomy on akinesia was moderate and correlated with a larger lesion volume. The positive effect of pallidotomy on dyskinesias, dystonia and tremor was more pronounced and unrelated to the size of the lesion. The effect of thalamotomy on tremor was also unrelated to the lesion volume. The location of the pallidal lesions correlated only with the effect on akinesia: the more posterior the lesion in the pallidum, the better the effect on this symptom. For thalamotomy, there was no relationship between lesion location and effect on tremor. It is concluded that improvement in akinesia following pallidotomy is more difficult to obtain than improvement of the other parkinsonian symptoms, and this improvement requires a larger lesion which is located very posterior in the ventral pallidum.

  • 13.
    Hariz, Marwan I
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Krack, Paul
    Melvill, Roger
    Jorgensen, Jan V
    Hamel, Wolfgang
    Hirabayashi, Hidehiro
    Department of Neurosurgery, Nara, Japan.
    Lenders, Mathieu
    Wesslen, Nils
    Tengvar, Magnus
    Yousry, Tarek A
    A quick and universal method for stereotactic visualization of the subthalamic nucleus before and after implantation of deep brain stimulation electrodes2003In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 80, no 1-4, p. 96-101Article in journal (Refereed)
    Abstract [en]

    For deep brain stimulation (DBS) of the subthalamic nucleus (STN), it would be an advantage if the STN could be visualized with fast acquisition of MR images, allowing direct and individual targeting. We present a protocol for T2-weighted, nonvolumetric fast-acquisition MRI, implemented at 8 centers in 6 countries. Acquisition time varied between 3 min 5 s and 7 min 48 s according to the center, and imaging often provided visualization of the STN on axial and coronal scans. Postoperatively, the same imaging protocol permitted visualization of the target area and DBS electrodes with minimum artifacts. This imaging technique may contribute to a decrease in the number of electrode passes at surgery.

  • 14.
    Hariz, Marwan I
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Shamsgovara, P
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Johansson, F
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurology.
    Hariz, Gun-Marie
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Fodstad, H
    Tolerance and tremor rebound following long-term chronic thalamic stimulation for Parkinsonian and essential tremor1999In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 72, no 2-4, p. 208-218Article in journal (Refereed)
    Abstract [en]

    Fifty-eight patients, 36 with essential tremor (ET) and 22 with Parkinson's disease (PD), received deep brain stimulation (DBS) in the thalamic ventral intermediate (Vim) nucleus. The mean follow-up was 17 months for ET and 21 months for PD patients. Stimulation parameters were adjusted as needed, at various intervals after surgery. Results were assessed using routine clinical evaluation and established outcome scales. All patients needed incremental increase in stimulation parameters at various intervals during the first 6-12 months after surgery. The mean voltage 1 week postoperatively was 1. 45 V in PD patients, and 1.37 V in ET patients. Twelve months later, the figures were 2.14 V in PD and 2.25 V in ET patients. At 1 year, the Essential Tremor Rating Scale (ETRS) improved from 54 to 28 (p < 0.0001). The motor part of the Unified Parkinson's Disease Rating Scale (UPDRS) improved from 37 to 26 (p < 0.01). Tremor items of the UPDRS improved more markedly (p < 0.0001). One week postoperatively 90% of PD, and 89% of ET patients were tremor free. One year later, 70% of PD and 60% of ET patients remained mostly tremor free. Upon switching off stimulation, there was a clear tendency for tremor rebound (p = 0.07) in the PD group, requiring continuous 24-hour stimulation in some patients. Permanent non-adjustable ataxia was induced by stimulation in 2 PD patients.

  • 15.
    Hirabayashi, Hidehiro
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Hariz, Marwan I
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Fagerlund, M
    Comparison between stereotactic CT and MRI coordinates of pallidal and thalamic targets using the Laitinen noninvasive stereoadapter1998In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 71, no 3, p. 117-130Article in journal (Refereed)
    Abstract [en]

    The coordinates of one and the same target were compared between stereotactic CT and MRI studies, using the original Laitinen noninvasive Stereoadapter, and a slightly modified stereoadapter in 34 patients scheduled for pallidotomy or thalamotomy. The differences between CT and MRI coordinates were significant for the anteroposterior y (p < 0.001) and the vertical z (p < 0.01) coordinates. When the targets were analyzed separately for the coordinates in the right and left hemispheres, only those of the left-sided targets were significantly different between CT and MRI measurements. In patients where a vertex support was added to the Stereoadapter, there were no differences between CT and MRI target coordinates, regardless of the side of the target. However, in all patient groups, the three-dimensional vectorial difference between CT and MRI coordinates showed that the MRI-defined targets lay anterior and dorsal, that is, rostral, to the CT-defined targets, with a 95% confidence interval of the differences ranging from 1.8 to 2.4 mm. This rostral shift in target coordinates on MRI versus CT happens to coincide with the usual approach of the probe towards the target during surgery. It is concluded that the differences in target coordinates in our study are due partly to MRI distortion and partly to repositioning error of the Stereoadapter on the head. The relatively low magnitude of these differences does not preclude the use of the Stereoadapter for MRI-guided functional stereotactic surgery, provided careful impedance monitoring and macrostimulation of the target area prior to lesioning.

  • 16.
    Hirabayashi, Hidehiro
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Hariz, Marwan I
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Wårdell, K
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Impact of parameters of radiofrequency coagulation on volume of stereotactic lesion in pallidotomy and thalamotomy2012In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 90, no 5, p. 307-315Article in journal (Refereed)
    Abstract [en]

    Background: One of the many reasons why lesional surgery for movement disorders has been more or less abandoned may have been the difficulty in predicting the shape and size of the stereotactic radiofrequency (RF) lesion. Objectives: To analyse the contribution of various RF coagulation parameters towards the volume of pallidotomies and thalamotomies. Methods: The relationship between temperature of coagulation, length of coagulated area and duration of coagulation on the one hand, and lesion volume on the other was retrospectively evaluated. Lesion diameters were measured on stereotactic thin-slice CT and MRI scans, and volumes of lesions were calculated concerning 36 pallidotomies and 14 thalamotomies in 46 patients who were operated using the same RF generator and same RF electrode. Results: The coagulation temperature, length of coagulated area and duration of coagulation were all correlated to the lesion volume. However, for a given length of coagulated area, the lesion's size was most strongly influenced by the temperature. Despite this clear correlation, and the relatively homogenous coagulation parameters, the lesions' volumes were markedly scattered. Conclusions: The volume of the stereotactic RF lesions could be correlated with the coagulation parameters, especially the temperature, at a group level, but could not be predicted in individual patients based solely on the RF coagulation parameters.

  • 17. 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.

  • 18.
    Johansson, Johannes D
    et al.
    Department of Biomedical Engineering, Linköping University, Linköping.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Haj-Hosseini, Neda
    Department of Biomedical Engineering, Linköping University, Linköping.
    Bergenheim, A Tommy
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Eriksson, Ola
    Department of Biomedical Engineering, Linköping University, Linköping.
    Wårdell, Karin
    Department of Biomedical Engineering, Linköping University, Linköping.
    Combined diffuse light reflectance and electrical impedance measurements as a navigation aid in deep brain surgery2009In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 87, no 2, p. 105-113Article in journal (Refereed)
    Abstract [en]

    AIM: The aim of this study is to assess reflected light intensity combined with impedance as a navigation aid during stereotactic neurosurgery.

    METHODS: During creation of 21 trajectories for stereotactic implantation of deep brain stimulation electrodes in the globus pallidus internus or subthalamus (zona incerta or subthalamic nucleus), impedance at 512 kHz and reflected light intensity at 780 nm were measured continuously and simultaneously with a radio frequency electrode containing optical fibres. The signals were compared with the anatomy, determined from pre- and post-operative MRI and CT. The measurements were performed within minutes, and signal analysis was done post-operatively.

    RESULTS: Reflected light intensity was low from the cortex, lateral ventricle, caudate nucleus and putamen; intermediate from the globus pallidus and thalamus; while it was high from the subcortical white matter, internal capsule and subthalamus. The electrical impedance was less consistent, but generally low in the cortex, intermediate in the subcortical white matter, putamen, globus pallidus and thalamus, and high in the internal capsule and subthalamus.

    CONCLUSION: Reflected light intensity and electrical impedance give complementary information about passed tissue, and the combination seems promising as a navigation aid during stereotactic neurosurgery.

  • 19.
    Lindvall, Peter
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Bergström, Per
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Blomquist, Michael
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Bergenheim, A Tommy
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Radiation schedules in relation to obliteration and complications in hypofractionated conformal stereotactic radiotherapy of arteriovenous malformations2010In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 88, no 1, p. 24-28Article in journal (Refereed)
    Abstract [en]

    AIMS: The purpose of this investigation was to assess the obliteration rate and complications following different radiation schedules of hypofractionated conformal stereotactic radiotherapy for cerebral arteriovenous malformations (AVMs). METHODS: Twenty-five patients were treated with 35 Gy in 5 fractions, whereas 31 patients were treated with 30-32.5 Gy (mean: 31.6 +/- 0.23 Gy) in 5 fractions. A complete angiographic follow-up is available for 40 patients. RESULTS: Thirty-seven out of 40 patients (92.5%) have so far shown obliteration of their AVMs after a mean time of 3.2 +/- 0.26 years (range: 2-8 years). The mean AVM volume in these patients was 8.2 +/- 1.0 cm(3) (range: 1.5-29 cm(3)). There was a higher rate of obliteration (88%) in patients treated with 35 Gy compared to those treated with < 35 Gy (78%), even if this was not statistically significant. There was a significantly shorter time to obliteration in patients treated with 35 Gy. All patients who experienced symptomatic radionecrosis belonged to the group treated with 35 Gy. CONCLUSION: A radiation schedule of 35 Gy in 5 fractions may be more effective than a radiation schedule of <35 (30-32.5) Gy in obliterating AVMs. This may, however, be at the price of an increased risk of symptomatic radionecrosis.

  • 20. Nakajima, Takeshi
    et al.
    Zrinzo, Ludvic
    Foltynie, Thomas
    Olmos, Iciar Aviles
    Taylor, Chris
    Hariz, Marwan I.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Limousin, Patricia
    MRI-Guided subthalamic nucleus deep brain stimulation without microelectrode recording: can we dispense with surgery under local anaesthesia?2011In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 89, no 5, p. 318-325Article in journal (Refereed)
    Abstract [en]

    Aims: Subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD) is traditionally performed under local anaesthetic (LA). STN visualization and routine validation of electrode location on stereotactic MRI may allow surgery under general anaesthesia (GA). This study compares the clinical outcome of MRI-guided STN DBS performed under LA or GA in a consecutive patient series. Methods: Unified Parkinson's Disease Rating Scale motor scores (UPDRS-III) in 14 GA patients (mean age 56.1 years, disease duration 13.8 years) were compared with those of 68 LA patients (mean age 57.5 years, disease duration 15.2 years). Results: Baseline UPDRS-III were worse in the GA group, both on medication (GA: 20.9 +/- 10.8; LA: 13.2 +/- 7.8, p < 0.01) and off medication (GA: 57.9 +/- 16.6; LA: 48.2 +/- 15.7, p < 0.05). On stimulation off medication motor scores significantly improved in both groups (GA: 27.3 +/- 11.8, mean 12-month follow-up; LA: 23.7 +/- 11.8, mean 14-month follow-up). The percentage improvement was similar in both groups (GA: 52.8%; LA: 50.8%, p = 0.96). Transient surgical complications occurred in 1 GA and 7 LA patients.

    Conclusions: MRI-guided STN DBS under GA with routine stereotactic verification of lead location did not have a negative effect on efficacy or safety. Surgery under GA is a viable option in patients who would find it hard to tolerate awake surgery due to disease severity, comorbidities or anxiety. Copyright (C) 2011 S. Karger AG, Basel

  • 21. Pepper, Joshua
    et al.
    Zrinzo, Ludvic
    Mirza, Bilal
    Foltynie, Thomas
    Limousin, Patricia
    Hariz, Marwan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    The Risk of Hardware Infection in Deep Brain Stimulation Surgery Is Greater at Impulse Generator Replacement than at the Primary Procedure2013In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 91, no 1, p. 56-65Article in journal (Refereed)
    Abstract [en]

    Background/Aims: Infection of implanted hardware after deep brain stimulation (DBS) has a significant impact on patient morbidity. We examined all patients who underwent DBS procedures over the last 9 years in our centre to assess the infection rate and possible factors related to surgery that may predispose to infection. Methods: Surgical reports and clinical notes were reviewed in 273 consecutive patients who underwent a total of 519 DBS-related procedures in our institute between November 2002 and September 2011. Results:Sixteen separate hardware-related infections occurred in 11 patients. Infections occurred in 3% of all procedures and 4% of all patients. The infection rate after implantable pulse generator (IPG) replacement surgery was more than three times higher than after de novo DBS surgery. In addition, male patients were more likely to develop device-related infections. Conclusions: It is unclear why infection rates should be more than three times higher after IPG replacement surgery than after the de novo procedure. The former is a shorter and simpler procedure to conduct. Perhaps the use of better antimicrobial protection and rechargeable batteries may be useful strategies to reduce infections following IPG revision surgery.

  • 22. Rzesnitzek, Lara
    et al.
    Hariz, Marwan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience. UCL Institute of Neurology, London, UK.
    Krauss, Joachim K.
    The Origins of Human Functional Stereotaxis: A Reappraisal2019In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 97, no 1, p. 49-54Article, review/survey (Refereed)
    Abstract [en]

    In order to shed light on the first application of human functional stereotactic neurosurgery, whether it was in the realm of movement disorders, as has been claimed repeatedly, or in the realm of psychiatry, a review of the original scholarly literature was conducted. Tracking and scrutinising original publications by Spiegel and Wycis, the pioneers of human stereotactic neurosurgery, it was found that its origin and the very incentive for its development and first clinical use were to avoid the side effects of frontal leucotomy. The first applications of functional stereotactic neurosurgery were in performing dorsomedial thalamotomies in psychiatric patients; it was only later that the stereotactic technique was applied in patients with chronic pain, movement disorders and epilepsy. Spiegel and Wycis' first functional stereotactic operations were for obsessive-compulsive disorder, schizophrenia, and other psychiatric conditions.

  • 23.
    Sandström, Linda
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Karlsson, Fredrik
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Unilateral Left Deep Brain Stimulation of the Caudal Zona Incerta Is Equally Effective on Voice Tremor as Bilateral Stimulation: Evidence from 7 Patients with Essential Tremor2018In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 96, no 3, p. 157-161Article in journal (Refereed)
    Abstract [en]

    BACKGROUND/AIMS: Deep brain stimulation (DBS) is less effective on voice tremor than arm tremor, and it is generally assumed that successful voice tremor treatment requires bilateral DBS and possibly more precise thalamic stimulation. However, recent findings suggest that these assumptions should be reconsidered.

    OBJECTIVES: To evaluate whether unilateral DBS targeting the caudal zona incerta (cZi) may be sufficient to alleviate voice tremor in patients with essential tremor, or whether bilateral stimulation is needed.

    METHODS: Seven patients with voice tremor off stimulation were evaluated during bilateral stimulation using their clinical settings, and during unilateral left stimulation in iterations with increasing stimulation amplitude. Two expert listeners assessed voice tremor severity in all samples in a blinded procedure.

    RESULTS: Six patients had comparable or better effects with unilateral left stimulation compared to bilateral stimulation. For the seventh patient, unilateral DBS at a slightly higher amplitude achieved similar results as bilateral DBS. Overall, high-amplitude stimulation did not appear to be beneficial on voice tremor.

    CONCLUSIONS: Unilateral left and bilateral cZi-DBS had comparable effects on voice tremor in the investigated group of 7 patients. This finding suggests that the assumption that bilateral DBS is required to treat voice tremor may need to be reconsidered.

  • 24. Wårdell, Karin
    et al.
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Richter, Johan
    Antonsson, Johan
    Eriksson, Ola
    Zsigmond, Peter
    Bergenheim, A Tommy
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Hariz, Marwan I
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Intracerebral microvascular measurements during deep brain stimulation implantation using laser Doppler perfusion monitoring2007In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 85, no 6, p. 279-286Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to investigate if laser Doppler perfusion monitoring (LDPM) can be used in order to differentiate between gray and white matter and to what extent microvascular perfusion can be recorded in the deep brain structures during stereotactic neurosurgery. An optical probe constructed to fit in the Leksell Stereotactic System was used for measurements along the trajectory and in the targets (globus pallidus internus, subthalamic nucleus, zona incerta, thalamus) during the implantation of deep brain stimulation leads (n = 22). The total backscattered light intensity (TLI) reflecting the grayness of the tissue, and the microvascular perfusion were captured at 128 sites. Heartbeat-synchronized pulsations were found at all perfusion recordings. In 6 sites the perfusion was more than 6 times higher than the closest neighbor indicating a possible small vessel structure. TLI was significantly higher (p < 0.005) and the perfusion significantly lower (p < 0.005) in positions identified as white matter in the respective MRI batch. The measurements imply that LDPM has the potential to be used as an intracerebral guidance tool.

  • 25. Åstrom, Mattias
    et al.
    Samuelsson, Jennifer
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Roothans, Jonas
    Fytagoridis, Anders
    Ryzhkov, Maxim
    Nijlunsing, Rutger
    Blomstedt, Patric
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Prediction of Electrode Contacts for Clinically Effective Deep Brain Stimulation in Essential Tremor2018In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 96, no 5, p. 281-288Article in journal (Refereed)
    Abstract [en]

    Background/Aim: Deep brain stimulation (DBS) is an established neurosurgical treatment that can be used to alleviate symptoms in essential tremor (ET) and other movement disorders. The aim was to develop a method and software tool for the prediction of effective DBS electrode contacts based on probabilistic stimulation maps (PSMs) in patients with ET treated with caudal zona incerta (cZi) DBS. Methods: A total of 33 patients (37 leads) treated with DBS were evaluated with the Essential Tremor Rating Scale (ETRS) 12 months after surgery. In addition, hand tremor and hand function (ETRS items 5/6 and 11-14) were evaluated for every contact during stimulation with best possible outcome without inducing side effects. Prediction of effective DBS electrode contacts was carried out in a retrospective leave-one-out manner based on PSMs, simulated stimulation fields, and a scoring function. Electrode contacts were ranked according to their likelihood of being included in the clinical setting. Ranked electrode contacts were compared to actual clinical settings. Results: Predictions made by the software tool showed that electrode contacts with rank 1 matched the clinically used contacts in 60% of the cases. Contacts with a rank of 1-2 and 1-3 matched the clinical contacts in 83 and 94% of the cases, respectively. Mean improvement of hand tremor and hand function was 79 +/- 21% and 77 +/- 22% for the clinically used and the predicted electrode contacts, respectively. Conclusions: Effective electrode contacts can be predicted based on PSMs in patients treated with cZi DBS for ET. Predictions may in the future be used to reduce the number of clinical assessments that are carried out before a satisfying stimulation setting is defined.

  • 26. Åström, Mattias
    et al.
    Tripoliti, Elina
    Hariz, Marwan I
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Neurosurgery.
    Zrinzo, Ludvic U
    Martinez-Torres, Irene
    Limousin, Patricia
    Wårdell, Karin
    Patient-specific model-based investigation of speech intelligibility and movement during deep brain stimulation2010In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 88, no 4, p. 224-233Article in journal (Refereed)
    Abstract [en]

    Special attention to stimulation-induced speech impairments should be taken in cases when active electrodes are positioned medial and/or posterior to the center of the subthalamic nucleus.

1 - 26 of 26
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf