Interventions - Neurosurgery for Treatment Refractory Psychiatric Disorders

Interventions

Currently, only a few specialized centers in the world conduct neurosurgical procedures for treatment-refractory OCD and treatment-refractory MDD. These procedures have evolved at particular centers more by convention and experience than by controlled research studies and direct comparison of the various procedures. The modern neurosurgical procedures include 1) cingulotomy, 2) anterior capsulotomy, 3) subcaudate tractotomy and 4) limbic leukotomy. All four procedures involve magnetic resonance (MR) imaging guided stereotactic lesions placed bilat-erally in the various target regions, after which they are named.

Results of Comparative Reviews of Outcome

Chiocca and Martuza (1990) reviewed 10 studies (n 5 210) in-volving all four current procedures to investigate comparative efficacy. After acknowledging the inherent limitations of such a comparison, the authors concluded that the percentages of pa-tients who improved with each of these four procedures were roughly the same. This latter conclusion may be disputed, how-ever, because the number of outcome categories was not iden-tical (e.g., A, B and C for limbic leukotomy; A and B only for capsulotomy).

Waziri (1990) reviewed 12 studies (n 5 253) of patients un-dergoing stereotactic interventions for treatment-refractory OCD and noted that 38% of patients were reported to be symptom free, 29% markedly improved, 10% unchanged and 3% worse or dead on follow-up (including one suicide). An overall figure for satisfactory response to surgery of 67% was found in these 253 OCD patients.

Hodgkiss and colleagues (1995) reported on a 12-month follow-up study of 286 patients who underwent SST between 1979 and 1991 (249 were completely evaluated including 74 who were evaluated by an independent rater); 63/183 (34%) MDD pa-tients and 5/15 (33%) of OCD patients were classified as good outcome. There were six deaths during this period though none was attributed to neurosurgery or suicide. The authors noted that most deaths involved patients over 70 and cautioned the use of this procedure for the elderly.

The methodological issues discussed earlier and the lack of rigorous, controlled and/or head to head comparison stud-ies prevent comment on which of these procedures is superior. This is further complicated by the heterogeneous profile of OCD patients. At present, there is little evidence to suggest the clear superiority of one procedure over another. More research ad-dressing these issues is desirable.

Predictors of Outcome

Most investigators reporting outcome studies concerning vari-ous procedures have naturally attempted to identify predictors of outcome, though these have been elusive. Bridges and col-leagues (1973) reported that OCD subjects who were considered responders in their study had an older age of onset (mean 28.5 years) versus nonresponders (mean 22 years). In a prospective cingulotomy study, using comprehensive assessment strate-gies, Baer and colleagues (1995) reported that the presence of symmetry obsessions, ordering and hoarding compulsions were predictive of lower YBOCS score at final follow-up (partial cor-relations). More recently, Rauch and colleagues (2001) utilizing a retrospective design, reported that higher preoperative meta-bolic rates in a single right posterior cingulate locus (determined by FDG-PET) was associated with better postcingulotomy out-come in II OCD patients. The advantages of predicting response in such invasive palliative procedures are obvious and need fur-ther study.