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  • Author or Editor: Kim J. Burchiel x
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Jacques Favre, Jamal M. Taha, Timothy Steel and Kim J. Burchiel

✓ The authors report a new technique to anchor deep brain stimulation electrodes using a titanium microplate. This technique has been safely used to secure 20 quadripolar deep brain stimulation electrodes implanted for movement disorders (18 electrodes) and pain (two electrodes). Twelve electrodes were implanted in the thalamus, four in the subthalamic nucleus, and four in the pallidum. No electrode migration or rupture occurred, and all electrodes have been shown to work properly after internalization of the system.

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Jamal M. Taha, Jacques Favre, Thomas K. Baumann and Kim J. Burchiel

✓ 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-µ-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 (≥ 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 proffer two conclusions: 1) after pallidotomy, tremor improves by at least 50% in two-thirds of patients with Parkinson's disease who have severe (≥ 50 mm on the VAS) preoperative tremor; and 2) better tremor control is obtained when tremor-synchronous cells are included in the lesion.

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Jamal M. Taha, Jacques Favre, Thomas K. Baumann and Kim J. Burchiel

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 (PD) who had drug-induced dyskinesia, bradykinesia, rigidity, and tremor underwent posteroventral pallidotomy. Using a 1-μ-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 (>= 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 proffer two conclusions: 1) after pallidotomy, tremor improves by at least 50% in two-thirds of patients with PD who have severe (>= 50 mm on the VAS) preoperative tremor; and 2) better tremor control is obtained when tremor-synchronous cells are included in the lesion.

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Jamal M. Taha, Jacques Favre, Thomas K. Baumann and Kim J. Burchiel

✓ Information is limited on the characteristics and topographic localization of pallidal kinesthetic cells in patients with Parkinson's disease. The authors analyzed the data from 298 neurons recorded in 38 patients with Parkinson's disease who underwent pallidotomy via microrecording techniques. Sixty-five neurons (22%) responded to passive movement of contralateral limbs. Of 17 kinesthetic cells that were tested in six patients, seven (41%) responded to ipsilateral limb movement as well. Nineteen cells (6%) fired synchronously with tremor. More kinesthetic cells were activated (63%) than inhibited (28%) by movement of single (68%) rather than multiple (32%) joints, and proximal (75%) rather than distal (25%) joints. The lateral globus pallidus externus (GPe) and medial globus pallidus internus (GPi) pallidal segments contained similar proportions of kinesthetic cells, activated or inhibited cells, arm- or leg-activated cells, and cells responding to single or multiple joints. Significantly more kinesthetic cells that responded to distal joints were recorded in GPi compared to GPe segments (p = 0.01). Arm and leg cells had similar characteristics pertaining to activation versus inhibition and responses to single, multiple, proximal, or distal joint movements. Arm and leg cells were somatotopically organized in GPi. Arm cells were clustered at the rostral and caudal segments of GPi and leg cells were clustered centrally. In GPe, leg cells were clustered at the caudal border. No somatotopic organization was identified for activated or inhibited cells; cells that responded to single, multiple, proximal, or distal joints; tremor-synchronous cells; or cells responding to specific joints within somatotopic arm or leg cells. It is concluded that kinesthetic cells provide a roadmap that localizes limb cells during pallidotomy. More studies are needed to identify the clinical significance of the different characteristics of kinesthetic cells.