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Parkinson’s Disease Slide Library Version 2.0 - All Contents Copyright © WE MOVE 2001

The Surgical Treatment of Parkinson’s Disease

Part 6 of 7

Surgical Treatments for Parkinson’s Disease

• Ablative– thalamotomy– pallidotomy

• Electrical stimulation– VIM thalamus, globus pallidus internus, sub-

thalamic nucleus

• Transplant– autologous adrenal, human fetal, xenotransplants,

genetically engineered transplants

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Technical Aspects of Pallidotomy

• Sterotactic placement using a Leksell frame• Macro-electrode placement: patient awake

– assess for weakness and visual changes

• Micro-electrode placement: confirmation using characteristic GPi cell firing patterns and comparing to those of visual tracts (photic stimulation) and other adjacent nuclei

• Lesioning : 1-3 radiofrequency lesions at 75o C

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Improvements with Pallidotomy

• Specific Features:– Dyskinesia 70-90 %– Wearing off dystonia 70-90 % – Tremor 25-60 %– Rigidity 25-50 %– Bradykinesia 25-50 %– Gait 25-50 %

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Effects of Pallidotomy

• Mostly contralateral to surgical side

• Immediate effect

• Improvements in cardinal features generally mimic those of levodopa:– markedly improved dyskinesia– moderately improved “off” scores– mildly improved “on” scores

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Features Unresponsive to Pallidotomy

• Dementia

• Bulbar

• Pure balance (gait improves)

• Autonomic

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Ideal Patient for Pallidotomy

• Severe dyskinesia with best medical management

• Fluctuations with best medical management

• Asymmetric symptoms

• Levodopa responsive

• Absence of significant :– dementia– bulbar symptoms– autonomic symptoms www.wemove.org

Unilateral vs. Bilateral Pallidotomy

• The second-side pallidotomy can :– significantly improve residual unilateral dyskinesia

– moderately improve residual cardinal PD features

– possibly improve axial symptoms

• However second-side pallidotomy can:– worsen bulbar symptoms

– possibly slow cognition

– tends not to have as dramatic effect as the first

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Pallidotomy Complications

• Hemorrhage (2 - 6 %)

• Weakness (2 - 8 %)

• Visual field deficit (0 - 12 %)

• Confusion (0 - 8 %)

• Weight gain (50 - 70%)

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Thalamotomy

• Significant improvement in contralateral tremor– depends on correct placement

• Minimal improvement in other PD signs

• Bilateral procedures poorly tolerated

• AEs: bulbar, sensory and motor deficits, gait, surgical complications

• Gradually being replaced by thalamic DBS

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Deep Brain Stimulation (DBS)

• High frequency, pulsatile, bipolar electrical stimulation

• Stereotactically placed into target nucleus

• Can be activated and deactivated with an external magnet

• Exact physiology unknown, but higher frequencies mimic cellular ablation, not stimulation

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Adjustable Features

• Voltage (1-7 volts)

• Pulse width (65-450 msec)

• Frequency (130-180 Hz)

• Polarity

• Lead location (4 leads, each 1.5 mm apart)

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VIM Thalamic DBS

• 80% reduction in contralateral arm and leg tremor• Possible mild improvement in bradykinesia and

rigidity• No functional improvement (UPDRS part II), but

significant improvement based upon global scores• No effect: gait and bulbar symptoms• AEs: bulbar, gait, paresthesia, surgical

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Bilateral Thalamic VIM DBS

• Bilateral tremor control very good, but adverse events (gait and bulbar) become more problematic (PD>ET)

• Often not able to completely inhibit both sides without AEs

• Subjective ratings do not improve much from those of unilateral scores

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Relative Advantages of Thalamotomy vs.

Thalamic Stimulation • Thalamotomy

– Proven long term efficacy

– Lower cost– Less risk of

infection– Less post-operative

management

• Thalamic Stimulation– Adjustable– Less morbidity– Easier to use

bilaterally– Greater efficacy?

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Subthalamic DBS

• All cardinal features of PD noted to improve in open label trials

• “Off” UPDRS improved 60%

• “On” UPDRS improved 10%

• Dyskinesia tends to improve but this is probably due to decreased levodopa dose

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Bilateral Subthalamic DBS

• Bilateral placement appears to be superior to unilateral placement

• Theorized neuroprotective mechanism, but no clinical evidence supporting this

• AE: confusion and hallucinations, increased dyskinesia before medication adjustments, eyelid opening apraxia, weight gain, surgical complications

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Globus Pallidus internus DBS

• Effects tend to mimic those of pallidotomy• Significant improvement in dyskinesia• Moderate improvement in cardinal “off” signs• No comparison between unilateral and bilateral • Bilateral DBS may be better tolerated than

bilateral pallidotomy

• AE: surgical complications

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Cell Transplants

• Autologous adrenal transplants– No efficacy

• Allogenic human fetal transplants– Initial encouraging clinical results

• Xenogenic fetal transplant (porcine and bovine) – Preliminary results pending

• Genetically engineered cells– Research ongoing

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Human Fetal Transplants

• Efficacy– Encouraging preliminary results in young (<60) PD pts– Patients greater than 50 years did not improve– PET studies consistent with cell functioning– Autopsies (2) show cell survival

• Problems– 4-10 embryos < 10 weeks gestation needed– Immunosuppression requirements unknown– Numerous technical problems– Potential for dyskinesias, even without any

PD medicationswww.wemove.org

Faculty for the WE MOVE Parkinson’s Disease Teaching Slide Set

Mark Stacy, MDBarrow NeurologicalInstitutePhoenix, Arizona, USA

Charles H. Adler, MD, PhDMayo Clinic ScottsdaleScottsdale, Arizona, USA

Kathleen Albany, PT, MPHWE MOVENew York, New York, USA

Richard B. Dewey, Jr., MDUniversity of Texas Southwestern Medical CenterDallas, Texas, USA

William G. Ondo, MDBaylor College of MedicineHouston, Texas, USA

Rajesh Pahwa, MDUniversity of Kansas Medical CenterKansas City, Kansas, USA

Ali H. Rajput, MDRoyal University HospitalSaskatoon, Saskatchewan, Canada

Lisa M. Shulman, MDHealth Policy FellowU.S. House of RepresentativesWashington, DC, USA

Celia Stewart, PhDMount Sinai Medical CenterNew York, New York, USA

Reviewed by the Education Committee of the Movement Disorder Society

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