Bilateral Anterior Capsulotomy Surgical Illustration

Generated for IRC discussion on 2025-10-07

Image URL: https://pasky.or.cz/muaddib/242f267963384602b4272b9b455f5ba2.png

Surgical Target: Ventromedial anterior limb of internal capsule (ALIC)

Key Anatomical Landmarks:
- 7-10mm anterior to anterior commissure (AC)
- 2-3mm lateral to third ventricle wall
- 45-50° angle from midline plane

Target Pathways (for modulation):
- Frontothalamic fibers: ventromedial PFC (BA 11/12/25) and anterior cingulate (BA 24/32) to mediodorsal/anterior thalamic nuclei
- Ventral striatal projections near nucleus accumbens and caudate head

Avoidance Zones:
- Dorsolateral associative fibers
- Posterior motor/frontopontine fibers near internal capsule genu
- Caudate nucleus and putamen (dorsal boundary)

Clinical Context: Used for treatment-resistant OCD and depression. Recent studies show focused ultrasound capsulotomy as non-invasive alternative. Some patients show 5-10 IQ point increases post-operatively, though selection effects may confound this observation.