Parkinson’s Disease: Lesions

Abstract

Targeted therapeutic surgical lesioning for Parkinson disease has a history extending over 100 years, involving almost every level of the central nervous system often with serendipitous discovery of therapeutic approaches. Despite a near abandonment of lesioning for Parkinson disease after the introduction of levodopa, a resurgence of interest in lesioning was appreciated after recognizing limitations of medications over time in some patients. While the introduction of deep brain stimulation has made lesioning second-line treatment in some parts of the world, unilateral stereotactic lesioning remains an effective and viable option for therapeutic intervention, particularly in an era with incisionless approaches for targeted lesioning. Stereotactic lesioning has been established as an efficacious and safe surgical option for patients with Parkinson disease with suboptimal symptom control or levodopa-induced dyskinesias who had previously responded to levodopa therapy, providing substantial therapeutic relief of tremor, bradykinesia, rigidity, and dyskinesias with some risk of weakness, speech alterations, and visual field deficits. Thalamotomy provides near-complete arrest of tremor with some risk of paresthesias, weakness, and dysarthria. Results vary based on modality used. In this chapter, the functional anatomy and physiologic basis of lesioning for each potential target (thalamus, pallidum, and subthalamic nucleus) are reviewed in detail. Given therapeutic alternatives of deep brain stimulation, comparisons between stimulation and lesioning are likewise detailed, including a thorough discussion of indications and contraindications for therapeutic stereotactic lesioning for Parkinson disease. Surgical preparation, technique, and outcomes are detailed for radiofrequency ablations, focused ultrasound, and radiosurgical approaches.