Unilateral pallidotomy in advanced Parkinson's disease: a retrospective study of 26 patients.

OBJECTIVE: To evaluate the effects of unilateral pallidotomy in patients with Parkinson's disease (PD). PATIENTS AND METHODS: Twenty-six patients with PD and disabling dyskinesias, painful and/or disabling dystonia, and/or pain as part of PD despite optimal pharmacotherapy underwent unilateral pallidotomy. For assessment, the Unified Parkinson's Disease Rating Scale (UPDRS; part II and III), Hoehn and Yahr staging, the Schwab and England scale, a Dyskinesia Rating Scale, and timed tests were used. Assessment was performed in defined "off' and "on," and on average 2 months before and 7.5 months after the unilateral pallidotomy. Adverse effects were classified as transient or permanent and as major or minor. RESULTS: In the "off' phase, the median UPDRS II score improved from 26.5 to 20.5 (23%) and the median UPDRS III score improved from 47.5 to 33.0 (31%). In the "on" phase, dyskinesias contralateral to the side of the procedure improved with 88% ipsilateral dyskinesias improved only temporarily, and the total UPDRS II and III scores remained unchanged. Thirteen patients had transient adverse effects, three patients had permanent, and two patients had a combination of transient and permanent adverse effects. The transient adverse effects in two patients were classified as major. CONCLUSION: Stereotactic unilateral pallidotomy can improve symptoms and disability in the "off' phase. In the "on" phase, dyskinesias disappeared at the side contralateral to the procedure. Permanent minor complications of pallidotomy occurred in 19% of the patients.     

Long term outcome of unilateral pallidotomy: follow up of 15 patients for 3 years

OBJECTIVES: With the advent of new antiparkinsonian drug therapy and promising results from subthalamic and pallidal stimulation, this study evaluated the long term efficacy of unilateral pallidotomy, a technique which has gained popularity over the past decade for the management of advanced Parkinson's disease. METHODS: The 15 patients reported here are part of the original cohort of 24 patients who underwent posteroventral pallidotomy for motor fluctuations and disabling dyskinesias 3 years ago as part of a prospective study. Evaluation scales included the unified Parkinson's disease rating scale, the Goetz dyskinesia scale, and the Purdue pegboard test. RESULTS: When compared with the prepallidotomy scores, the reduction in the limb dyskinesias and off state tremor scores persisted on the side contralateral to pallidotomy at the end of 3 years (dyskinesias were reduced by 64% (p<0.01) and tremor by 63% (p<0.05). Other measures tended to deteriorate. The dosage of antiparkinsonian medications did not change significantly from 3 months prepallidotomy to 3 years postpallidotomy. CONCLUSIONS: Although unilateral pallidotomy is useful in controlling the contralateral dyskinesias and tremor 3 years after surgery, all other early benefits disappear and activities of daily living continue to worsen.     

Outcome of unilateral pallidotomy in advanced Parkinson's disease: cohort study of 32 patients

OBJECTIVES: In a randomised trial to study the efficacy of unilateral pallidotomy in patients with advanced Parkinson's disease, patients having pallidotomy within 1 month after randomisation were compared with patients having pallidotomy 6 months after the primary outcome assessment. Of the 37 patients enrolled 32 had a unilateral pallidotomy. The follow up study of these patients is presented to report (1) clinical outcome; (2) adverse effects; (3) cognitive and behavioural effects; (4) relation between lesion location and outcome; and (5) preoperative patient characteristics predictive for good outcome. METHODS: Outcome measures were the motor section of the unified Parkinson's disease rating scale (UPDRS), levodopa induced dyskinesias, disability, quality of life, and a comprehensive neuropsychological assessment. Multivariate logistic regression was used to identify preoperative patient characteristics independently associated with good outcome. RESULTS: Off phase assessment showed a reduction in parkinsonism from 49 to 36.5 points on the UPDRS 6 months after surgery. Improvements were also demonstrated for activities of daily living and quality of life. In the on phase dyskinesias were reduced. All effects lasted up to 12 months after surgery. Three patients had major permanent adverse effects. Besides worsening of verbal fluency after left sided surgery, systematic cognitive deterioration was not detected. Patients taking less than 1000 levodopa equivalent units (LEU)/day were more likely to improve. CONCLUSIONS: The positive effects of unilateral pallidotomy are stable up to 1 year after surgery. Patients taking less than 1000 LEU per day were most likely to improve.     

Randomized trial of pallidotomy versus medical therapy for Parkinson's disease

Thirty-six patients with Parkinson's disease (PD) were randomized to either medical therapy (N = 18) or unilateral GPi pallidotomy (N = 18). The primary outcome variable was the change in total Unified Parkinson's Disease Rating Scale (UPDRS) score at 6 months. Secondary outcome variables included subscores and individual parkinsonian symptoms as determined from the UPDRS. At the six month follow-up, patients receiving pallidotomy had a statistically significant reduction (32% decrease) in the total UPDRS score compared to those randomized to medical therapy (5% increase). Following surgery, patients' showed improvement in all the cardinal motor signs of PD including tremor, rigidity, bradykinesia, gait and balance. Drug-induced dyskinesias were also markedly improved. Although the greatest improvement occurred on the side contralateral to the lesion, significant ipsilateral improvement was also observed for bradykinesia, rigidity and drug-induced dyskinesias. A total of twenty patients have been followed for 2 years to assess the effect of time on clinical outcome. These patients have shown sustained improvement in the total UPDRS (p < 0.0001), "off" motor (p < 0.0001) and complications of therapy subscores (p < 0.0001). Sustained improvement was also seen for tremor, rigidity, bradykinesia, percent on time and drug-induced dyskinesias.     

Subthalamic deep brain stimulation in patients with a previous pallidotomy.

The safety and efficacy of subthalamic nucleus (STN) deep brain stimulation (DBS) in patients who have had a previous unilateral pallidotomy is not clear. We identified 10 patients (9 male) at the Baylor College of Medicine Parkinson's Disease Center who underwent STN DBS after prior unilateral pallidotomy. Demographics, efficacy as determined by off Unified Parkinson's Disease Rating Scale (UPDRS) part III scores, and levodopa equivalent dosing were analyzed. We then compared these to an age- and sex-matched group of 25 DBS patients who had no prior pallidotomy. After their initial pallidotomy (mean age, 51.8 +/- 10.8 years), the mean UPDRS motor off medicine scores improved from 51.3 +/- 14.3 to 34.9 +/- 12.8, and the UPDRS dyskinesia score improved from 1.8 +/- 1.0 to 0.8 +/- 0.7. Their STN DBS off UPDRS motor scores (mean age, 56.0 +/- 10.2 years) improved by 16.0% from 53.1 +/- 9.7 (range, 42-68) to 44.6 +/- 11.1 (range, 25-67). In contrast, the UPDRS off motor scores in a control group of 25 DBS patients improved by 49.9%, from 49.7 +/- 11.1 to 25.7 +/- 18.9, (16.0% vs. 49.9%; P < 0.001). Changes in UPDRS dyskinesia scores were similar in both groups. AE thought to be related to the STN DBS following pallidotomy included worse dysarthria (three) and worse balance (two). STN DBS patients with prior pallidotomy had less improvement in UPDRS off motor score compared to other STN DBS patients, despite relatively good outcomes immediately after their pallidotomy. This may be partially due to a selection bias, but it may also indicate that prior pallidotomy is a negative predictor of outcome of STN DBS and should be considered in patient selection.     

Subthalamic nucleus stimulation in advanced Parkinson's disease: blinded assessments at one year follow up

OBJECTIVE: To measure the effect of deep brain stimulation (DBS) of the subthalamic nucleus in patients with advanced Parkinson's disease. DESIGN: Open label follow up using blinded ratings of videotaped neurological examinations. PATIENTS: 30 patients with advanced Parkinson's disease (19 male, 11 female; mean age 58.8 years; mean disease duration 12.8 years), complicated by intractable wearing off motor fluctuations and dopaminergic dyskinesias. MAIN OUTCOME MEASURES: Unified Parkinson's disease rating scale (UPDRS), part III (motor), score at one year, from blinded reviews of videotaped neurological examinations. Secondary outcomes included the other UPDRS subscales, Hoehn and Yahr scale, activities of daily living (ADL) scale, mini-mental state examination (MMSE), estimates of motor fluctuations and dyskinesia severity, drug intake, and patient satisfaction questionnaire. RESULTS: Subthalamic nucleus stimulation was associated with a 29.5% reduction in motor scores at one year (p<0.0001). The only important predictors of improvement in UPDRS part III motor scores were the baseline response to dopaminergic drugs (p = 0.015) and the presence of tremor (p = 0.027). Hoehn and Yahr scores and ADL scores in the "on" and "off" states did not change, nor did the mean MMSE score. Weight gain occurred in the year after surgery, from (mean) 75.8 kg to 78.5 kg (p = 0.028). Duration of daily wearing off episodes was reduced by 69%. Dyskinesia severity was reduced by 60%. Drug requirements (in levodopa equivalents) declined by 30%. CONCLUSIONS: The 30% improvement in UPDRS motor scores was a more modest result than previously reported. DBS did not improve functional capacity independent of drug use. Its chief benefits were reduction in wearing off duration and dyskinesia severity.     

Comparison of Contralateral Pallidotomy vs. Pallidal Stimulation After Prior Unilateral Pallidotomy for Parkinson’s Disease

Objectives: Pallidal stimulation and pallidotomy are known to improve the symptoms of Parkinson's disease (PD). However, it is not known which modality produces greater benefit in patients who have already undergone unilateral pallidotomy. It is also suggested that the original pallidal surgery provides a greater benefit than subsequent pallidal surgery. The aim of this study was to analyze which modality produced greater PD symptom improvement in patients with a prior pallidotomy and whether the chronological order of the pallidal surgery influenced the size of the improvement. Methods: Five patients who had undergone a prior unilateral pallidotomy for PD were studied. Because of ongoing Parkinsonian symptoms, all patients subsequently underwent contralateral pallidal surgery, either a further pallidotomy or pallidal stimulation. All surgeries were performed by a single functional neurosurgeon and the patients prospectively assessed and scored at routine follow‐ups. Paired‐sample t‐tests were used to detect differences in outcomes after first and second surgeries. Results: Two patients underwent pallidal stimulation and three underwent a second pallidotomy. Mean follow‐up was 13.5 months and 12.3 months, respectively. Greater percentage improvements in the majority of scores were found after pallidal stimulation compared with a second pallidotomy, namely Unified Parkinson's Disease Rating Scale (UPDRS) II off (25.22% vs. −3.27%), UPDRS III off (36.15% vs. 5.21%), rigidity (58.34% vs. 11.54%), tremor (5.56% vs. −30.48%), bradykinesia (48.55% vs. −2.23%), gait composite (16.52% vs. −51.79%), dyskinesia duration (83.33% vs. 66.67%), dyskinesia disability (100% vs. 66.67%), speech (10% vs. −50%), and the proportion of the day spent in the “off” state (50% vs. 25%). Comparing outcomes after the first surgery to those after the second surgery, statistical differences were found in dyskinesia duration improvement and ipsilateral dyskinesia improvement after the second surgery (p < 0.004 and p = 0.021, respectively). Conclusions: Pallidal stimulation produced greater symptom improvement than a second pallidotomy and subsequent surgery did not produce inferior results to the original pallidal surgery.     

微电极记录技术在帕金森病手术治疗价值

目的　总结微电极导向立体定向手术治疗帕金森病的临床经验及治疗效果。方法　自 1 999年 4月至 2 0 0 1年 2月采用微电极导向立体定向手术治疗帕金森病 350例 ,其中苍白球腹后部毁损术 (PVP) 2 78例 ,丘脑腹中间核 (Vim)毁损术 35例 ,同期同侧PVP和Vim毁损术 1 5例 ,行同期双侧PVP 1 1例 ,分期双侧PVP 8例 ,分期一侧PVP或另一侧Vim毁损术 3例。对手术前后的“关”状态和“开”状态进行生活能力评分、UPDRS评分 ,并进行门诊随访。结果　术后日常生活能力评分“关”状态提高 2 9.8% ,“开”状态提高 2 5 .9%。UPDRS :在“关”状态下 ,总的改善率为 57.3 % ,其中精神行为情绪改善率为 50 .8% ,日常活动改善率 59.1 % ,运动功能改善率 58.2 %。结论　PVP对震颤效果不如Vim毁损术 ,对震颤明显 ,无明显僵直的患者可选择Vim毁损术 ,对震颤僵直型患者可分期双侧PVP毁损术。     

Bilateral pallidotomy in Parkinson's disease: a retrospective study.

We evaluated the effects of bilateral pallidotomy in patients with advanced Parkinson's disease. Thirteen patients with Parkinson's disease had a staged bilateral pallidotomy if they had severe response fluctuations, dyskinesias, painful dystonia, or bradykinesia despite optimum pharmacological treatment. Assessment scales were the Unified Parkinson's Disease Rating scale (UPDRS), the Schwab and England scale, and a questionnaire on the effects of disability in activities of daily living and adverse effects. Postoperative magnetic resonance imaging was evaluated for lesion location and extension. The median off-phase UPDRS motor score was reduced from 43.5 to 29 after the first pallidotomy, and it was further reduced to 23.5 after the second pallidotomy (n = 8). The UPDRS activities of daily living off-phase score improved from 28.5 to 20.5 after the first pallidotomy and to 19 after the second pallidotomy (n = 6). The Schwab and England scale off-phase score showed an improvement after both procedures, first from 40 to 60, and thereafter to 90 (n = 8). On-phase dyskinesias were reduced substantially. Eight patients had adverse effects, of whom five had problems with speech. One patient became hemiplegic due to a delayed infarction. Ten patients experienced further benefit from the second procedure. Bilateral pallidotomy reduces dyskinesias. A second contralateral pallidotomy may reduce parkinsonism, although to a lesser degree compared with the first pallidotomy and with an increased risk for adverse effects.     

Treatment of advanced Parkinson's disease by unilateral posterior GPi pallidotomy: 4-year results of a pilot study.

To assess the long-term outcome following unilateral pallidotomy for advanced Parkinson's disease, we performed nonblinded Core Assessment Program for Intracerebral Transplantations protocol assessments in 10 of the original 15 patients in our pilot study for 4 years following surgery. Although Unified Parkinson's Disease Rating Scale motor examination scores returned to baseline levels at 3 and 4 years, most patients continued to show sustained improvements in contralateral tremor, akinesia, and drug-induced dyskinesias. Contralateral tremor was absent at 4 years in all seven patients with preoperative tremor. Contralateral "off" arm movement times (averaged for three tasks) decreased by 37% at 1 year and by 30% at 4 years. Contralateral dyskinesia scores improved by 82% at 1 year and by 64% at 4 years. In contrast, after reaching speeds equal to the contralateral side at 1 year, ipsilateral "off" movement times increased by 13% over baseline levels at 4 years. Although most gait and postural stability measures showed modest initial improvement followed by a return to baseline values, "on" stand-walk-sit task performance declined significantly at 4 years. Despite the restriction of our surgeries to one side and the expected natural progression of Parkinson's disease, the results of patient self-assessments suggest that 4 years after unilateral pallidotomy, most patients continue to experience a quality of life above preoperative levels.     

Weight gain following unilateral pallidotomy in Parkinson's disease

OBJECTIVE: To determine the clinical correlates and infer pathogenesis of weight gain following pallidotomy in patients with Parkinson's disease (PD). BACKGROUND: Surgical ablation of the globus pallidus internus (GPi) improves levodopa induced dyskinesias, moderately improves most other "cardinal" manifestations of PD, and has been noted to result in increased weight. METHODS: We incorporated Unified Parkinson's Disease Rating Scales (UPDRS) subscales, the Beck depression inventory and feeding questionnaire data into a linear regression model in order to determine which post-surgical change(s) may lead to weight gain over the first year following pallidotomy, n = 60. RESULTS: The mean weight gain 1 year after pallidotomy was 4.0 +/- 4.1 kg. Improvement in "off" motor scores (P < 0.005), especially gait subscores (P<0.0001), and to a lesser extent improvement in "on" motor scores (P<0.05) predicted weight gain. Changes in dyskinesia ratings, mood, food intake, dysphagia, levodopa dose, weight loss in the year prior to pallidotomy, age, and duration of PD did not correlate with subsequent weight gain. CONCLUSION: The high correlation between post-pallidotomy weight gain and "off" motor scores, suggests that this phenomenon is related to some change in underlying homeostasis associated with changes in the cardinal manifestations of PD itself, rather than secondary changes resultant from the surgery.     

Clinical outcome of unilateral stereotactic pallidotomy without microelectrode recording for intractable Parkinson's disease

Objective: To study the effects of unilateral stereotactic pallidotomy performed without microelectrode recording for advanced Parkinson's disease. Methods: Stereotactic coordinates were calculated by comparing preoperative inversion recovery MRI sequences with intraoperative CT scans. Conventional stereotactic stimulation techniques were employed to confirm correct probe placement. Patients were assessed using a modified CAPIT protocol with the off-state UPDRS motor score as the primary efficacy measure. Results: A statistically significant decline in off-state UPDRS motor scores occurred at 2months (21% improvement in 32 patients) and also at 1year postoperatively (30% improvement in 12 patients). Levodopa-induced dyskinesias on the side contralateral to surgery were reduced 97% in the cohort with 1year of follow-up. No deleterious effects of surgery on global neuropsychological functioning were seen. A major surgical complication (mild but persistent hemiparesis) occurred in one patient. Conclusions: We believe that stereotactic pallidotomy can be performed safely and effectively without microelectrode recording when coordinates are calculated using CT with comparison to preoperative MRI sequences.     

Stereotactic posteroventral pallidotomy: clinical methods and results at 1-year follow up.

Twenty consecutive patients with idiopathic Parkinson's disease underwent stereotactic posteroventral pallidotomy. Schwab and England ADL scores in the "off" state were improved by 18% and in the "on" state the scores declined by 2%. Three patients also reported marked improvement in "off" state dystonia. One-year data are available on 12 patients who underwent evaluations according to the Core Assessment Program for Intracerebral Transplantation protocol preoperatively and at 3, 6, and 12 months after surgery. Significant improvements in Unified Parkinson's Disease Rating Scale sections II and III scores in the "off" state, composite "off" state scores of bradykinesia and rigidity, contralateral tremor in the "off" state, and contralateral dyskinesias were observed. Although there was reduction in the daily levodopa dose, this did not reach statistical significance. Major complications (15%) included hemiparesis (one of 20) and visual field cuts (two of 20); minor complications (45%) included mild cognitive dysfunction (four of 20), reading difficulty not related to visual disturbance (one of 20), and 5-10 lb weight gain (four of 20).     

Acute and chronic effects of anteromedial globus pallidus stimulation in Parkinson''s disease

OBJECTIVE: To evaluate the effects of acute and chronic stimulation in the anteromedial part of the globus pallidus internus (GPi) on the symptoms of patients with Parkinson's disease. METHODS: Six patients with severe Parkinson's disease (Hoehn and Yahr stage 4-5 in "off" drug condition) with motor fluctuations and levodopa induced dyskinesia (LID) were operated on. Chronic electrodes were implanted in the anteromedial GPi bilaterally in five patients and unilaterally in one patient. The effect of stimulation via the four contacts for each electrode (n=11) was assessed postoperatively on the contralateral parkinsonian signs in the off condition and on the contralateral and ipsilateral LID in the "on" condition. The core assessement program for intracerebral transplantation protocol was performed before surgery and then 1, 3, and 6 months after surgery in on and off conditions and in on and off stimulation conditions. RESULTS: Stimulation performed postoperatively showed a significant improvement (p<0.05) by 47% (contralateral rigidity) and 32% (contralateral bradykinesia) when stimulation was applied through the distal contact. Levodopa induced dyskinesias were improved by 95% (contralateral LID) and by 66% (ipsilateral LID) when stimulation was applied through the distal contact. Six months after the surgery, GPi stimulation in the off condition led to a mean improvement in the motor score of UPDRS by 36%. The mean daily duration in the off state decreased by 52% (p<0.05). The mean duration of LIDs decreased by 68% (p<0.05) and their severity by 53% (p<0.05). CONCLUSION: Chronic stimulation in the anteromedial GPi shows that this is a safe and effective treatment for advanced Parkinson's disease with benefit sustained for at least 6 months.     

Outcomes following staged bilateral pallidotomy in advanced Parkinson's disease

The authors assessed clinical outcome for up to one year after staged bilateral pallidotomy in 14 patients with advanced PD. One year after surgery, dyskinesias were virtually abolished and there were significant reductions in "off" time (67%) and activities of daily living "off" scores (24%), as well as nonsignificant reduction in "off" motor score (39%); "on" scores were unchanged. One patient developed a visual field deficit; two had transient confusion. Staged bilateral pallidotomy improves motor function in selected patients with advanced PD.     

Four year follow-up study after unilateral pallidotomy in advanced Parkinson's disease

BACKGROUND: Pallidotomy is widely accepted as a treatment for patients with Parkinson's disease (PD) who have disabling symptoms that are inadequately controlled with pharmacotherapy. There are, however, only a few studies, with a small number of patients, showing evidence after prolonged periods of time about the clinical outcome after pallidotomy. METHODS: We have conducted a four-year follow-up study of 23 patients with PD who had undergone unilateral pallidotomy. Six patients were lost to follow-up. The remaining 17 were evaluated before surgery and at three months, one year, and four years after surgery, following standard protocols. RESULTS: At four years, patients still showed significant amelioration in contralateral and axial dyskinesias and off-period contralateral parkinsonian signs. Total motor UPDRS and Activities of Daily Living scores also remained improved four years after surgery. Ipsilateral and axial parkinsonian symptoms and Hoehn & Yahr and Schwab & England scales were not significantly changed from baseline values. The initial beneficial effects on motor fluctuations were not maintained at last visit. All patients considered themselves to be improved with respect to their clinical condition before surgery in a clinical global impression estimation done at the four-year follow-up. CONCLUSION: Unilateral pallidotomy can provide sustained improvement of contralateral parkinsonism and dyskinesias during at least four years. Early benefits observed in axial symptoms and motor fluctuations wane with time. On period akinesia worsened significantly in the limbs contralateral to pallidotomy after four years.     

Effects of pallidotomy and levodopa on walking and reaching movements in Parkinson's disease.

We examined the effects of levodopa and unilateral pallidotomy on quantitative measures of walking and reaching in Parkinson's disease (PD). We also compared quantitative measures of movement with standard clinical rating scales. We used kinematic measures and the Unified Parkinson's Disease Rating Scale (UPDRS) motor subscale (subscale III) to evaluate the movement of 10 people with PD. Subjects were tested after withholding PD medications for at least 8 hours and again 30 to 45 minutes after taking the first morning dose of levodopa. They were studied in this manner before unilateral pallidotomy and then 3.5 to 10 months after surgery. The UPDRS motor subscale was performed in each state. Kinematic data were collected as subjects reached to a target and walked. The UPDRS motor subscale ratings were similar to those reported in the literature: pallidotomy improved the overall motor score and the contralateral bradykinesia + rigidity score, but not the gait + posture score. In contrast, kinematic measures demonstrated that levodopa and pallidotomy had different effects on walking and reaching speed. Both treatments improved walking speed, and the effect was additive. Levodopa improved reaching speed before pallidotomy but did not improve it as much after pallidotomy. Additionally, pallidotomy had inconsistent effects on reaching; some subjects were faster and others were slower. The subjects who initially reached more slowly improved after pallidotomy; the subjects who initially reached more normally (faster) worsened after pallidotomy. On the basis of our results, we speculate that basal ganglia output pathways that control walking and reaching may be distinct, such that bilateral projections to the pedunculopontine area influence walking, whereas ipsilateral thalamocortical projections influence reaching.     

Pallidotomy and quality of life in patients with Parkinson's disease: an early study.

The purpose of this study was to analyze the effect of stereotactic neurophysiologically guided pallidotomy on health-related quality of life (QoL) of patients with Parkinson's disease (PD). Eleven patients with PD (seven men, four women; mean age, 57.2 years; mean duration of disease, 14 years) with motor complications refractory to medical therapy underwent unilateral pallidotomy. Clinical assessment was carried out a week before surgery and 4 months after the surgical procedure and was based on the Core Assessment Program for Intracerebral Transplantations protocol. QoL was measured by means of the PDQ-39. A set of rating scales (Hoehn & Yahr, Unified Parkinson's Disease Rating Scale, Schwab and England, Northwestern University Disability Scale of Walking, Abnormal Involuntary Movement Scale), timed tests, and self-evaluations of motor function and mood were applied. Improvement was found in dyskinesias (74%) and off-period disability (42%). Cardinal motor signs improved significantly (30%-59%). Four dimensions of the PDQ-39 (Mobility, ADL, Emotions, Bodily Pain) showed a significant improvement (p <0.01-0.001). The global effect on QoL, measured through the PDQ-39 Summary Index (35.3%; 95% confidence interval: 15.60-54.97), was also significant (p<0.01) but unrelated to major clinical changes. Pallidotomy significantly improves QoL in patients with advanced PD. QoL measurement provides relevant information that is probably not attainable by clinical assessment.     

Dyskinesias induced by subthalamotomy in Parkinson's disease are unresponsive to amantadine

BACKGROUND: Dyskinesias are a transient but severe complication of subthalamotomy in some patients. PATIENTS AND METHODS: Three patients with Parkinson's disease undergoing bilateral micro-recording guided surgery of the subthalamic nucleus (STN) are described; deep brain stimulation (DBS) was used in one case, and subthalamotomy in the other two. Prior to surgery, levodopa induced dyskinesia had improved (< or = 50%) under treatment with amantadine (400 mg/day, po) in all three patients. The patient treated with DBS developed severe dyskinesia a few days after discharge and began self medication with amantadine but showed no improvement. This suggested a possible lack of response to amantadine for treatment of dyskinesias induced by surgery of the STN. RESULTS: Both patients treated with bilateral subthalamotomy developed unilateral choreoballistic movements immediately after surgery, despite not taking levodopa (L-dopa). Patients were scored using the dyskinesia scale and started treatment with 400 mg amantadine (po) for 4 days within the first postoperative week with no effect on dyskinesia score or its phenomenology. Amantadine was therefore discontinued. One month after surgery both patients were free of involuntary movements with an improvement of about 60% in the "off" state UPDRS motor score. Six month follow up showed maintained antiparkinsonian benefit, without need for levodopa treatment and complete absence of dyskinesia. CONCLUSION: The present findings suggest that: (i) amantadine probably exerts its anti-dyskinetic effect by acting on the "indirect" pathway; (ii) the pathophysiological mechanisms of subthalamotomy induced dyskinesias may differ from those involved in L-dopa induced dyskinesias; (iii) dyskinesias induced by STN surgery resolve spontaneously as compensatory mechanisms develop.