Controversy: Ablative surgery vs deep-brain stimulation in the management of Parkinson’s disease

Introduction: The concept of surgically modulating the central nervous system as treatment for Parkinson’s disease (PD) has been in existence since the early 1900s [1]. At that time, lesions were made via craniotomies, initially involving the pyramidal and later the extrapyramidal systems. Lesion therapy as we know it today for PD has its origins in the late 1940s, when Spiegel and Wycis [2] introduced the stereotactic head frame, allowing surgeons to target subcortical structures without using an open, nonstereotactic approach. These pioneers performed and reported on 100 stereotactic pallidoansotomies for PD [3] using the same target that Russell Meyers had used during open surgery [4] and showed improvements in tremor and rigidity. In addition, in the early 1950s, Cooper made a serendipitous discovery (when he was “obliged to sacrifice” the anterior choroidal artery) that pallidotomy could improve the motor symptoms of PD [5, 6]. Pallidotomy continued to be performed through the 1950s [5-8] but then fell out of favor with the introduction of thalamotomy [9]. The ventrolateral thalamic target became favored based on neuroanatomical data [9] as well as, again, on serendipity, when Cooper found that a planned pallidal lesion was actually in the ventrolateral thalamus on autopsy. His report of impressive efficacy of the thalamic lesion on parkinsonian tremor helped drive most contemporary surgeons to choose the thalamus over the pallidum as the surgical target of choice [10]. In 1960, Svennilson et al. [11] kept the practice of pallidotomy alive by demonstrating that posteroventral pallidotomy was an effective therapy for all cardinal features of PD, and that posteriorly placed pallidal lesions produced superior results to those placed more anteriorly [11]. At the time, this work was largely ignored, and thalamotomy continued to be the procedure of choice [10]. With the advent of levodopa (l-DOPA), surgical therapy was largely abandoned until it was eventually recognized that the benefits of medical therapy came at a cost over time, in the form of levodopa-induced dyskinesias and motor fluctuations [12, 13]. In 1992, when Laitinen et al. [14] reintroduced Leksell’s posteroventral pallidotomy for PD and reported marked benefits in all cardinal motor signs of the disease (not just tremor), pallidotomy became the surgery of choice for patients with PD and motor complications.