Stereotactic radiosurgery for treatment-refractory obsessive-compulsive disorder: a systematic review of targets, targeting methods, lesion geometry, and clinical outcomes.

Clinical Snapshot

Key Findings

• P Value: Not reported in abstract

• Effect Size: Response rate: 57.1%; Remission rate: 36.8%; Severe delayed radiation-related injury: 6.4%

• Primary Outcome: Pooled clinical response rate in treatment-refractory OCD following radiosurgical capsulotomy

• Nnt Or Sensitivity: NNT cannot be calculated from single-arm data without a comparator. Approximately 1 in 16 patients (6.4%) experienced severe delayed radiation-related injury; approximately 1 in 2.7 patients (57.1%) achieved clinical response. These figures require contextualisation against the severity and chronicity of treatment-refractory OCD.

• Confidence Interval: Response: 95% CI 49.1%–64.9%; Remission: 95% CI 26.9%–47.9%; Severe injury: 95% CI 3.1%–12.8%

Clinical Application

SRS (e.g., Gamma Knife radiosurgery) is available at a limited number of highly specialised neurosurgical centres globally. The procedure is non-invasive relative to open neurosurgery but requires significant institutional infrastructure, radiation physics expertise, and long-term neuropsychiatric follow-up. Patient selection, informed consent regarding delayed adverse events, and post-procedural monitoring are resource-intensive. In Australia, SRS for psychiatric indications is not currently listed on the Medicare Benefits Schedule (MBS) for OCD, and there is no TGA-approved indication for radiosurgical capsulotomy in this context. Deep brain stimulation (DBS) for refractory OCD has received greater regulatory attention internationally. The RACGP and RANZCP guidelines for OCD management emphasise pharmacotherapy (SSRIs, clomipramine) and CBT as first-line treatments, with specialist referral for refractory cases. Any consideration of SRS in Australia would require ethics committee oversight, likely within a clinical trial framework, at centres such as those affiliated with Peter MacCallum Cancer Centre or major academic neurosurgical units. The 6.4% severe radiation injury rate would require careful disclosure under Australian informed consent standards. Adults with severe, chronic, treatment-refractory OCD who have failed adequate trials of multiple serotonin reuptake inhibitors, augmentation strategies, and evidence-based cognitive-behavioural therapy (including exposure and response prevention). Candidates require multidisciplinary psychiatric, neurological, and neurosurgical evaluation at a specialist centre with SRS capability.

Abstract

BACKGROUND: Stereotactic radiosurgery (SRS) is a noninvasive option for carefully selected patients with treatment-refractory obsessive-compulsive disorder (OCD), but the literature is heterogeneous in targets, targeting methods, lesion geometry, and outcomes. METHODS: PRISMA-guided systematic review of PubMed, Scopus, and Web of Science. Full-text human studies of radiosurgical capsulotomy for treatment-refractory OCD were included. Narrative synthesis was performed across technical and clinical domains. When ≥3 comparable studies reported the same endpoint, exploratory random-effects single-arm meta-analyses were performed. RESULTS: Twenty-one OCD-specific studies were included (1999-2024). The anterior limb of the internal capsule (ALIC), particularly the ventral ALIC, was the dominant target. Technique and dose reporting varied across cohorts, with commonly reported maximum doses spanning approximately 120-180 Gy, often using 4-mm collimation and single- or double-shot paradigms. Earlier reports primarily used anatomical MRI/coordinate-based targeting, whereas newer studies increasingly incorporated lesion mapping, tractography, and network-based analyses. Eleven cohorts were eligible for quantitative pooling. The pooled clinical response rate was 57.1% (95% CI, 49.1%-64.9%; I²=21.7%), and pooled remission was 36.8% (95% CI, 26.9%-47.9%; I²=0%). Severe delayed radiation-related injury was uncommon but present (6.4%, 95% CI, 3.1%-12.8%; I²=0%). Mechanistic studies suggested that lesion topography and pathway engagement may be more important than lesion size alone. CONCLUSIONS: SRS is a meaningful option for treatment-refractory OCD. The ventral ALIC remains the principal target, but outcomes likely depend on precise target identification and lesion placement. Standardized reporting and prospective evaluation of pathway-informed targeting are needed.

References

1. 1.Reyes, J. S., Bouras, A., Choi, S., Lunsford, L. D., Hadjipanayis, C. G., & Niranjan, A. (2026). Stereotactic radiosurgery for treatment-refractory obsessive-compulsive disorder: a systematic review of targets, targeting methods, lesion geometry, and clinical outcomes. Neurosurgical Review. https://doi.org/10.3171/2024.6.FOCUS24278