Efficacy of Gamma Knife Radiosurgery in Refractory Obsessive-Compulsive Disorder: An Indian Experience

Background Obsessive-compulsive disorder (OCD) is a chronic debilitating psychiatric condition with adverse impact on patient's sociooccupational health. Refractoriness to pharmacotherapy and psychotherapy is not uncommon. Gamma Knife radiosurgery (GKRS) is the comprehensively used and reviewed treatment modality in refractory OCD worldwide. In India, the past two decades of increasing GKRS availability has failed to create the necessary local awareness of its usefulness in refractory OCD. Limited native literature deepens the problem. Objective To analyze our experience with GKRS in refractory OCD, and report the safety and efficacy/long-term outcome in patients using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Materials and Methods A retrospective review of patients receiving GKRS for refractory OCD between 2000 and 2020 was carried out. Case files of the eligible (n = 9) patients were reviewed for clinical, radiotherapeutic, and outcome data. Additionally, patients were contacted via telephone to enquire about their experiences, and to obtain retroactive consent for GKRS in June 2021. Information obtained was collated, computed, and analyzed. Results Male-to-female sex ratio was 8:1. Mean age at the time of GKRS and mean duration of OCD prior to GKRS was 30.1 9.4 and 10.2 5.8 years, respectively. Mean baseline Y-BOCS score was 29.6 +/- 4.7. Our first patient received cingulotomy, while the rest underwent anterior capsulotomy. Median margin dose (50% isodose) was 70 Gy. Also, 23.8 +/- 7.7 was the mean Y-BOCS score at the last follow-up (median = 30 months). Overall, 44.4% patients showed full/partial response (>= 25% reduction in Y-BOCS score) at the last follow-up. In anterior capsulotomy (eight patients), patients with moderate/severe OCD showed better response (4/5 responders) than those with extreme OCD (0/3 responders). Single case of cingulotomy resulted in no response (<25% reduction in Y-BOCS score). No adverse radiation effects were noted. Also, 55.6% patients gave retroactive consent telephonically. Conclusion GKRS is a safe and effective noninvasive treatment modality for refractory OCD. Ventral anterior capsule is the preferred target. Maximum radiation doses of 120 to 160 Gy are well tolerated. Extremely severe OCD cases fared poorer. Proper awareness about the availability and efficacy of GKRS in refractory OCD is required in India.