Currently, neurosurgery is predominantly reserved for OCD patients with severe, incapacitating symptoms who have failed to improve adequately after aggressive use of behavioral and medication treatments.
Surgery is not recommended unless a multidisciplinary committee reaches consensus regarding its appropriateness for a given candidate and the patient gives informed consent.
The three main anatomical lesion sites for treatment of OCD are indicated in the Figure 10.1. In each procedure, bilateral lesions are made stereotactically under MRI-guidance.
The lesion target for an anterior cingulotomy is within the anterior cingulate cortex (Brodmann areas 24 and 32) at the margin of the cingulum white matter bundle. This brain region is involved in action monitoring.
FIGURE 10.1 Key anatomical lesion sites for psychosurgical treatment of OCD. Reprinted with permission from Lipsman N, Neimat JS,
Lozano AM: Deep Brain stimulation for treatment-refractory obsessive compulsive disorder: the search for a valid target. Neurosurgery. 2007; 61:1-13.
Anterior capsulotomy involves making lesions within the anterior limb of the internal capsule, impinging on the ventral stratum (part of the brain “reward system” which is likely to be involved in repetitive habits) immediately inferior to the capsule.
The intent is to interrupt fibers of passage between prefrontal cortex and subcortical nuclei including the dorsomedial thalamus. For over 15 years, capsulotomy has also been performed using the Leksell Gamma Knife, a radiosurgical instrument that makes craniotomy unnecessary.
This procedure targets the substantia innominata Qust inferior to the head of the caudate nucleus) with the goal of interrupting white matter tracts connecting the orbitofrontal cortex (involved in the generation of compulsions) to subcortical structures.
Limbic leukotomy combines subcaudate tractotomy and anterior cingulotomy (1+3).