Resident University of Chicago Department of Neurological Surgery
Introduction: Anterior capsulotomy is an effective treatment of refractory obsessive-compulsive disorder. Previous lesions were generated “blindly” (radiosurgery, radiofrequency) with low predictability and reproducibility. This study evaluates the effect of interstitial laser capsulotomy on patient outcomes and employing tractography for planning precise disconnections also weighs different parameters like lesion size, location, energy transfer and fractional anisotropy pre and post capsulotomy as predictive factors.
Methods: 50 patients with refractory OCD were enrolled into a study of LITT capsulotomy. All patients underwent complete neuropsychological workup before and after LITT. Tractography was performed pre- and post – surgery. Targeting was consistent based on DTI of orbito-frontal thalamic connections and all surgeries were performed by the same surgeon (PCW). All lesions were performed with the 980 nm Laser system (Visualase) using a 3T MRI (Phillips Ingenia). Outcomes and side effects were analyzed as to lesion size, location, energy transfer and FA patterns. Multivariate statistics were used to check for independent prognostic variables.
Results: 71% of patients were responders with 82 % showing immediate response within 24 hours on YBOCS. Response was not correlated with lesion size and energy transfer but location (p < 0.0001). Differential anisotropy analysis showed a 46 % reduction in fibers disconnected by capsulotomy which correlated with therapeutic efficacy (41% reduction in YBOCS). Temporary apathy inversely correlated with lesion size. No effects on executive function were observed.
Conclusion : LITT capsulotomy offers a precise and effective treatment of refractory OCD allowing larger disconnections with a much earlier symptom relief than alternative methods including HIFU. It results in structural changes of hyperconnectivity in OCD which could be employed as biomarkers of outcome and side effects.
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