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Current Abstracts for KJ Burchiel

1: Neurosurgery 2000 Feb;46(2):344-53; discussion 353-5

Outcome of unilateral and bilateral pallidotomy for Parkinson's disease: patient assessment.

Favre J, Burchiel KJ, Taha JM, Hammerstad J

Department of Neurosurgery, Ospedale Civico, Lugano, Switzerland.

OBJECTIVE: Pallidotomy has recently regained acceptance as a safe and effective treatment for Parkinson's disease symptoms. The goal of this study was to obtain the patients' perspective on their results after undergoing this procedure. Special attention was focused on the potential complications and the respective advantages and risks of unilateral versus bilateral pallidotomy.

METHODS: Fifty-six patients were studied during a 2-year period; 44 completed the evaluation, with a median follow-up of 7 months. Of these patients, 22 underwent unilateral pallidotomy, and 17 had bilateral simultaneous pallidotomy. Five patients who underwent staged bilateral pallidotomy were excluded from the statistical analysis, because the number of patients was considered too small for analysis. The procedures were performed with magnetic resonance imaging determination of the target, combined with physiological confirmation, including microelectrode recording.

RESULTS: According to Visual Analog Scale scores, unilateral pallidotomy significantly improved dyskinesias (P < 0.05) but no other symptoms. Simultaneous bilateral pallidotomy improved slowness, rigidity, tremor, and dyskinesias (P < 0.05) but worsened speech function (P < 0.05). According to the patients' most frequently chosen answers to multiple-choice questions, unilateral pallidotomy improved night sleep, muscle pain, freezing, overall "on," overall "off," and the duration of "off periods," but it worsened the volume of the voice and articulation, increased drooling, and reduced concentration. Bilateral pallidotomy improved night sleep, muscle pain, freezing, overall "on," overall "off," duration of "off periods," and the amount of medication taken, but it increased drooling and worsened the volume of the voice, articulation, and writing. Subjective visual disturbance was noted in 36 and 41% of patients who underwent unilateral and simultaneous bilateral pallidotomy, respectively. Globally, the result of the procedure was rated "good" or "excellent" by 64% of the patients who underwent unilateral pallidotomy and by 76% of the patients who underwent bilateral pallidotomy. An age less than 70 years was a positive prognostic factor for the global outcome (P < 0.05), as were severe preoperative dyskinesias (P < 0.05).

CONCLUSION: This study confirms that, from a patient standpoint, unilateral and simultaneous bilateral pallidotomy can reduce all the key symptoms of Parkinson's disease (i.e., akinesia, tremor, and rigidity) and the side effects of L-dopa treatment (i.e., dyskinesias). Preoperative severe dyskinesias and younger age are positive prognostic factors for a successful outcome. Simultaneous bilateral pallidotomy was more effective than unilateral pallidotomy regarding tremor, rigidity, and dyskinesias, but it conferred a higher risk of postoperative speech deterioration.

PMID: 10690723, UI: 20152582

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2: Neurosurgery 1999 Dec;45(6):1375-82; discussion 1382-4

Comparison of pallidal and subthalamic nucleus deep brain stimulation for advanced Parkinson's disease: results of a randomized, blinded pilot study.

Burchiel KJ, Anderson VC, Favre J, Hammerstad JP

Department of Neurological Surgery, Oregon Health Sciences University, Portland, USA.

OBJECTIVE: Deep brain stimulation (DBS) of the globus pallidus internus (GPi) and subthalamic nucleus (STN) has been reported to be effective in alleviating the symptoms of advanced Parkinson's disease (PD). Although recent studies suggest that STN stimulation may be superior to GPi stimulation, a randomized, blinded comparison has not been reported. The present study was designed to provide a preliminary comparison of the safety and efficacy of DBS at either site.

METHODS: Ten patients with idiopathic PD, L-dopa-induced dyskinesia, and response fluctuations were randomized to implantation of bilateral GPi or STN stimulators. Neurological condition was assessed preoperatively with patients on and off L-dopa and on DBS at 10 days and 3, 6, and 12 months after implantation. Patients and evaluating clinicians were blinded to stimulation site throughout the study period. Complete follow-up data were analyzed for four GPi patients and five STN patients.

RESULTS: When off-L-dopa, both GPi and STN groups demonstrated a similar response, with approximately 40% improvement in Unified PD Rating Scale motor scores after 12 months of DBS. Rigidity, tremor, and bradykinesia improved in both groups. In combination with L-dopa, Unified PD Rating Scale motor scores were more improved by GPi stimulation than by STN stimulation. On-L-dopa axial symptoms were clinically improved in the GPi but not the STN group. L-Dopa-induced dyskinesia was reduced by DBS at either site, although medication requirement was reduced only in the STN group. There were no serious intraoperative complications among patients in either group.

CONCLUSION: Pallidal and STN stimulation appears to be safe and efficacious for the management of advanced PD. A larger study is needed to investigate further the differences in symptom response and the interaction of L-dopa with stimulation at either site.

Publication Types:
Clinical trial
Randomized controlled trial

PMID: 10598706, UI: 20065765

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3: Neurosurg Clin N Am 1998 Apr;9(2):367-73

Ablative therapy for movement disorders. Complications in the treatment of movement disorders.

Louw DF, Burchiel KJ

Department of Neurological Surgery, Oregon Health Sciences University, Portland, Oregon 97201, USA.

Presently, there is a renaissance in the surgical treatment of movement disorders. Prompted by the growing recognition of the limitations of drug therapy, this resurgence has been further promoted by progress in neuronal transplantation, advances in neuroimaging and stereotactic surgical techniques, and innovative therapies, such as deep brain stimulation for abnormal movements. Mortality associated with thalamotomy and pallidotomy is rare, but morbidity is not inconsiderable, particularly in the elderly and those with preexisting brain damage. Judicious patient selection and physiologic confirmation of stereotactic targets are cornerstones to complication avoidance.

Publication Types:
Review
Review, tutorial

PMID: 9495898, UI: 98163477

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4: J Neurosurg 1997 Apr;86(4):642-7

Tremor control after pallidotomy in patients with Parkinson's disease: correlation with microrecording findings.

Taha JM, Favre J, Baumann TK, Burchiel KJ

Division of Neurosurgery, Oregon Health Sciences University, Portland, USA.

The goals of this study were to analyze the effect of pallidotomy on parkinsonian tremor and to ascertain whether an association exists between microrecording findings and tremor outcome. Forty-four patients with Parkinson's disease who had drug-induced dyskinesia, bradykinesia, rigidity, and tremor underwent posteroventral pallidotomy. Using a 1-mu-tip tungsten electrode, microrecordings were obtained through one to three tracts, starting 10 mm above the pallidal base. Tremor severity was measured on a patient-rated, 100-mm Visual Analog Scale (VAS), both preoperatively and 3 to 9 months (mean 6 months) postoperatively. Preoperatively, tremor was rated as 50 mm or greater in 24 patients (55%) and as less than 25 mm in 13 patients (30%). Postoperatively, tremor was rated as 50 mm or greater in five patients (11%) and less than 25 mm in 29 patients (66%). The difference was significant (p = 0.0001). Four patients (9%) had no postoperative tremor. Tremor improved by at least 50% in eight (80%) of 10 patients in whom tremor-synchronous cells were recorded (Group A) and in 12 (35%) of 34 patients in whom tremor-synchronous cells were not recorded (Group B). This difference was significant (p = 0.03). Tremor improved by at least 50 mm in all (100%) of the seven Group A patients with severe (> or = 50 mm) preoperative tremor and in nine (53%) of 17 Group B patients with severe preoperative tremor. This difference was also significant (p = 0.05). The authors prefer two conclusions: 1) after pallidotomy, tremor improves by at least 50% in two-thirds of patients with Parkinson's disease who have severe (> or = 50 mm on the VAS) preoperative tremor; and 2) better tremor control is obtained when tremor-synchronous cells are included in the lesion.

PMID: 9120628, UI: 97234139

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5: Stereotact Funct Neurosurg 1996;66(1-3):123-36

MRI distortion and stereotactic neurosurgery using the Cosman-Roberts-Wells and Leksell frames.

Burchiel KJ, Nguyen TT, Coombs BD, Szumoski J

Division of Neurosurgery, Oregon Health Sciences University, Portland, USA.

When not corrected, geometrically distorted magnetic resonance images may be unsuitable for stereotactic intracranial neurosurgical procedures where accuracy of target localization is critical. On a GE Signa 1.5-tesla system, we implemented an imaging protocol designed to improve the accuracy of the determination of target coordinates by means of multiple scans utilizing reversal of the frequency-encoded readout gradient. Using a Cosman-Roberts-Wells (CRW) frame and a phantom, geometric shifts of important image features were found to occur. In patients undergoing functional neurosurgical procedures with the CRW system, localization of the posterior commissure by corrected MR images was compared to that obtained by intraoperative ventriculography. Unexpectedly, severe distortions in MR images were revealed by the studies, with shifts of some fiducial markers of 10 mm from their estimated true position. Most of this distortion was attributable to the magnetic properties of the stereotactic frame, and could be eliminated by appropriate design and manufacture of the frame system. Images obtained with an MRI-compatible Leksell stereotactic frame were found to be relatively free of major geometric distortion. This study points out that properties of frame systems used for stereotactic neurosurgery may greatly influence the accuracy of frame-based stereotactic neurosurgery, and that the accuracy of these frame systems is testable.

PMID: 8938944, UI: 97093382

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6: Neurosurg Clin N Am 1995 Jan;6(1):55-71

Thalamotomy for movement disorders.

Burchiel KJ

Division of Neurosurgery, Oregon Health Sciences University, Portland 97201, USA.

VL thalamotomy is an excellent choice for the control of tremor in patients with a wide variety of disorders. Parkinson's disease and essential tremor are the best indications, but other disorders also respond. Improvement of bradykinesia and rigidity in Parkinson's disease is achievable but is not as dramatic as hyperkinetic symptoms. Morbidity from thalamotomy is most common with bilateral lesions, and innovative therapies such as thalamic stimulation may have a role when a second contralateral procedure is needed. Thalamotomy is an effective procedure that has probably been underused over the past two decades. With renewed interest in stereotactic neurosurgery, improved imaging, and well-established target localization techniques, the procedure is effective with a high degree of safety. The growing enthusiasm for brain grafting has also stimulated interest in the surgical treatment of movement disorders, and clearly this technique will evolve and progress as well. In the author's opinion, the results of ablative surgery still far exceed those of tissue implantation. For a select group of indications, thalamotomy should be considered in the forefront of options for patients with movement disorders.

Publication Types:
Review
Review, tutorial

PMID: 7696875, UI: 95210924

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7: Mov Disord 1993 Oct;8(4):519-24

Effects of thalamic stimulation on tremor, balance, and step initiation: a single subject study.

Burleigh AL, Horak FB, Burchiel KJ, Nutt JG

Department of Physiology, Oregon Health Sciences University, Portland.

This study was conducted to evaluate the clinically apparent balance improvements in a patient with Parkinson's disease who had stimulating electrodes surgically implanted to the VIM nucleus of the right thalamus for control of left-upper-extremity tremor. Experiments were conducted to determine if balance improved simply because the large-amplitude upper-extremity tremor was reduced or if the neural control of balance improved. Using EMGs and forceplate recordings, we quantified the effects of the thalamic stimulation on the contralateral upper-extremity tremor and on the lower-extremity postural muscle activations for quiet stance, step initiation, and equilibrium responses to surface displacements. The results demonstrated that, beside reducing the amplitude and destabilizing effects of the upper-extremity tremor, the thalamic stimulation was also effective in reducing tremor activity of the trunk and contralateral lower-extremity muscles. In addition, the contralateral lower-extremity muscle activation patterns, strengths, and durations for the balance tasks were enhanced during stimulation. These results suggest that thalamic stimulation improved this patient's balance by reducing tremor in the contralateral extremities and by increasing burst duration and magnitude of the tibialis anterior, which functions as the postural prime mover for the step initiation and balance tasks.

PMID: 8232365, UI: 94049874

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