Neurosurgical strategies for Gilles de la Tourette's syndrome

Abstract

Tourette's syndrome (TS) is a neurological disorder characterized by motor and vocal tics that typically begin in childhood and often are accompanied by psychiatric comorbidities. Symptoms of TS may be socially disabling and cause secondary medical complications. Pharmacological therapies remain the mainstay of symptom management. For the subset of patients in whom TS symptoms are medically recalcitrant and do not dissipate by adulthood, neurosurgery may offer an alternative treatment strategy. Greater understanding of the neuroanatomic and pathophysiologic basis of TS has facilitated the development of surgical procedures that aim to ameliorate TS symptoms by lesions or deep brain stimulation of cerebral structures. Herein, the rationale for the surgical management of TS is discussed and neurosurgical experiences since the 1960s are reviewed. The necessity for neurosurgical strategies to be performed with appropriate ethical considerations is highlighted.

Keywords: deep brain stimulation; neurosurgery; thalamus; tourette’s syndrome.

Figure 1

Schematic representation of basal ganglia circuitry (modified from Visser-Vandewalle et al 1997), with excitatory (glutamatergic) projections and inhibitory (GAB-Aergic) projections →. Normally, dopamine, acting via D1 dopamine receptors, has an excitatory influence on striatal projections to the GPi and, acting via D2 dopamine receptors, an inhibitory influence on striatal projections to the GPe, maintaining a balance between the activities of the direct and indirect basal ganglia pathways. According to the dopaminergic hypothesis of TS pathophysiology, dopaminergic hyperactivity causes increased activity in the direct pathway (indicated by the heavier weighted lines) and decreased activity in the indirect pathway, which serves to enhance thalamocortical activity. In TS, the thalamus, caudate-putamen, and GPe become pathologically hyperactive, and the GPi and STN become pathologically hypoactive. Abbreviations: GPi, globus pallidus pars internus; GPe, globus pallidus pars externus; STN, subthalamic nucleus; DA, dopamine.

Figure 2

Sagittal magnetic resonance image demonstrating the sites of lesions for TS. Notes: 1, frontal leucotomy; 2, cingulotomy; 3, zona incerta lesion; 4, thalamotomy; 5, hypothalamotomy; and 6, dentatotomy.