Cost analysis of unilateral and bilateral pallidotomy for Parkinson's disease

Pallidotomy after chronic deep brain stimulation

Recent publications have demonstrated that deep brain stimulation for Parkinson's disease still exerts beneficial effects on tremor, rigidity, and bradykinesia for up to 10 years after implantation of the stimulator. However with the progression of Parkinson's disease, features such as cognitive decline or “freezing” become prominent, and the presence of an implanted and functioning deep brain stimulator can impose a profound burden of care on the clinical team and family. The authors describe their experience in treating 4 patients who underwent removal of the implanted device due to either progressive dementia requiring full-time nursing or due to infection, and who subsequently underwent a unilateral pallidotomy.

Pharmacoeconomic considerations of treating patients with advanced Parkinson's disease

INTRODUCTION

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. In the later (advanced) stages of PD, the initial treatment of early PD becomes less effective and long-term side effects of dopaminergic treatment become apparent. In advanced PD, motor and non-motor complications occur, which increase treatment costs. Increasing disability and impaired activities of daily living concomitantly raise indirect costs, due to loss in productivity. Hence, the economic burden of advanced PD is substantial for both the society and the patients with their caregivers.

AREAS COVERED

A systematic literature search was performed involving the databases NHS CRD (National Health Service Centre for Reviews and Dissemination) and PubMed until July 15, 2011. "Parkinson" [Mesh] and "cost" were used as search terms in PubMed and only "Parkinson" in the CRD database.

EXPERT OPINION

Economic evaluations are scarce and heterogeneous, and their interpretation may be limited due to methodological shortcomings. Dopamine agonists, COMT and MAO-B inhibitors as well levodopa infusion and deep brain stimulation are reported to be cost-effective in the respective decision frameworks. However, these results are heavily dependent on assumptions of drug costs and effect sizes used in the models. More detailed real-life information from long-term clinical trials is needed to feed the economic models, especially for head-to-head comparisons. To date, no economic evaluation has been undertaken for possible neuroprotective/disease modifying effects, and further research is needed for evaluations of interventions for non-motor symptoms.

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.

Preparing the ethical future of deep brain stimulation

BACKGROUND

Deep brain stimulation is an approved and effective neurosurgical intervention for motor disorders such as PD and ET. Deep brain stimulation may also be effective in treating a number of psychiatric disorders, including treatment refractory depression and OCD. Although DBS is a widely accepted therapy in motor disorders, it remains an invasive and expensive procedure. The ethical and social challenges of DBS need further examination, and discussion and emerging applications of DBS in psychiatry may also complicate the ethical landscape of DBS.

METHODS

To identify and characterize current and emerging issues in the use of DBS, we reviewed the neurosurgical literature on DBS as well as the interdisciplinary medical ethics and relevant psychological and sociological literatures. We also consulted the USPTO database, FDA regulations and report decisions, and the business reports of key DBS manufacturers.

RESULTS

Important ethical and social challenges exist in the current and extending practice of DBS, notably in patient selection, informed consent, resource allocation, and in public understanding. These challenges are likely to be amplified if emerging uses of DBS in psychiatry are approved.

CONCLUSIONS

Our review of ethical and social issues related to DBS highlights that several significant challenges, although not insurmountable, need much closer attention. A combination of approaches previously used in neuroethics, such as expert consensus workshops to establish ethical guidelines and public engagement to improve public understanding, may be fruitful to explore.

Five-year follow-up of unilateral posteroventral pallidotomy in Parkinson's disease

BACKGROUND

Neurocognitive outcome research of individuals with Parkinson's disease after unilateral pallidotomy is inconsistent. Although some studies reported few cognitive changes, other investigations have more consistently shown both transient and long-term cognitive decline postoperatively.

METHODS

We report the long-term motor and neurocognitive outcome 5 years post surgery for 18 patients with Parkinson's disease (12 men and 6 woman; all right-handed) who underwent right or left unilateral posteroventral pallidotomy.

RESULTS

Pallidotomy patients revealed long-term motor benefits from the surgery in their "off" state and control of dopa-induced dyskinesias in their "on" state, which is consistent with previous research. We found mild declines in oral and visuomotor information processing speed, verbal recognition memory, and mental status 5 years after surgery, which differs from previous literature regarding the long-term neurocognitive outcome after pallidotomy. Differences between the right and left pallidotomy patients for both motor and cognitive skills were not found.

CONCLUSION

Although deep brain stimulation is presently the treatment of choice, pallidotomy continues to be performed around the world. Consequently, although unilateral pallidotomy should be considered a treatment option for patients with Parkinson's disease who suffer from severe unilateral disabling motor symptoms or dyskinesias, the long-term neurocognitive outcome should also be considered in treatment decisions.

Operative and hardware complications of deep brain stimulation for movement disorders

The objective of this investigation was to present the operative and hardware complications encountered during follow-up of patients with in situ deep brain stimulators. The study took the form of a retrospective chart review on a series of consecutive patients who were treated successfully with insertion of deep brain stimulators at a single centre by a single surgeon between 1999 and 2005. During the study period, a total of 60 patients underwent 96 procedures for implantation of unilateral or bilateral DBS electrodes. The mean follow-up period was 43.7 months (range 6-78 months) from the time of the first procedure. No patients were lost to follow-up or died. Eighteen patients (30%) developed 28 adverse events, requiring 28 electrodes to be replaced. Seven patients developed two adverse events and two patients developed three adverse events. The rate of adverse events per electrode-year was 8%. We observed a higher proportion of early complications (<6 months postoperatively) in patients with Parkinson's disease, while dystonic patients had more late complications (>6 months postoperatively) and no early complications. Thirty per cent of our patients developed an adverse event that could potentially lead to revision of the implanted hardware. In patients with Parkinson's disease most of the complications tend to occur during the first 6 months postoperatively, while in dystonic patients most occur between 12 and 24 months postoperatively.

Short and long-term motor and cognitive outcome of staged bilateral pallidotomy: a retrospective analysis

BACKGROUND

We investigated retrospectively the short and long-term motor and cognitive functioning of staged bilateral pallidotomy using motor testing and a comprehensive neuropsychological battery before and after each procedure.

METHODS

Fifteen patients with idiopathic Parkinson's disease were assessed at baseline and at least 3 months after each of their two staged surgeries. Motor and neuropsychological results were compared to 15 non-surgical Parkinson's disease patients matched for disease stage and mental status. In addition, nine bilateral pallidotomy patients were evaluated for long-term cognitive changes (>2 years).

FINDINGS

Bilateral pallidotomy patients demonstrated significant improvements in motor functioning in the "on" and "off" states and with dyskinesias after the first surgery, with an additional improvement reported for dyskinesias after the second procedure. On long-term follow-up, dyskinesia improvements were maintained. Bilateral pallidotomy patients did not show significant cognitive declines following both procedures on the short-term follow-up and when compared to the Parkinson's disease group. However, significant cognitive declines were found on the long-term follow-up evaluation.

CONCLUSIONS

Parkinson's disease patients received significant short- and long-term motor benefits, particularly reduced dyskinesias, following staged bilateral pallidotomy without significant short-term cognitive consequences. Two years following the second procedure, bilateral pallidotomy patients tended to show an increase in both motor and non-motor symptoms of Parkinson's disease, particularly cognitive decline.

Efficacy and safety of simultaneous bilateral pallidotomy in advanced Parkinson's disease

BACKGROUND

Although unilateral pallidotomy is generally considered a safe and effective neurosurgical treatment for advanced Parkinson's disease (PD), controversies concerning efficacy and adverse effects of bilateral posteroventral pallidotomy (PVP) exist and need to be resolved.

METHODS

We studied 8 patients with advanced PD who underwent simultaneous bilateral PVP. The patients were assessed preoperatively, immediately after surgery, and 6 and 12 months later.

RESULTS

Dyskinesia was almost entirely abolished immediately after surgery, as well as being significantly lower 1 year later (p < 0.05). The 'off' medication score of the Unified Parkinson's Disease Rating Scale motor part (UPDRS III) was significantly improved after surgery (p < 0.05) but increased gradually after 6 months. The off medication score of activities of daily living tended to improve immediately after surgery, but it returned to preoperative levels at 12 months. There were no major complications of surgery.

CONCLUSIONS

Simultaneous bilateral PVP may be a safe and highly effective method of reducing levodopa-induced dyskinesia. Our results suggest that simultaneous bilateral PVP may be a reasonable therapeutic option for advanced PD with severe levodopa-induced dyskinesia.