Habenula as a Marker of Thalamic Asymmetrical Skew and a Landmark for the Vim-Vc Boundary in MRgFUS Thalamotomy
In brief
Anterior habenular torsion triples risk of sensory side effects after MRgFUS thalamotomy
In 157 patients undergoing MR-guided focused-ultrasound thalamotomy, those with anterior habenular torsion experienced sensory complications in 43% immediately and 25% at one year, versus 14% and 5% in others. Tremor relief was similar across groups, suggesting torsion predicts side effects without affecting efficacy, and may guide safer targeting.
- Journal
- Stereotactic and functional neurosurgery (Q1)
- Published
- 10 September 2026
- Study design
- Cohort / observational study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Namiko Nishida, Yoshito Sugita, Masahiro Sawada, Kayoko Obora, Yosuke Taruno, Satoshi Kaneko, et al.
- PMID
- 42721101
- DOI
- 10.1159/sfn/aeuag008
Why clinicians should know about it
- Picked for Anatomy (paper of the day, 11 September 2026): Habenular torsion as neuroanatomical landmark
Abstract
BACKGROUND: Traditional targeting based on the anterior commissure-posterior commissure (AC-PC) line in MR-guided focused ultrasound (MRgFUS) thalamotomy does not account for individual thalamic asymmetry, potentially leading to suboptimal outcomes or adverse effects. OBJECTIVE: To investigate whether habenular torsion, an anatomical marker of thalamic asymmetry, predicts clinical outcomes and sensory side effects following ventral intermediate nucleus (Vim) thalamotomy. METHODS: We retrospectively analyzed 157 patients (essential tremor: 121; Parkinson's disease: 36) who underwent unilateral MRgFUS thalamotomy. Angular metrics, including the Torsion Index (inter-hemispheric habenular angular difference) and the Lesion-Habenula difference (based on a lesion axis originating from the midline-habenula intersection), were measured on axial MRI 2.0 mm dorsal to the AC-PC line. Tremor improvement (CRST) and ventralis caudalis (Vc)-related sensory symptoms were evaluated immediately and at the 1-year follow-up. RESULTS: Tremor improved by over 70% immediately after treatment, with no significant difference between torsion groups (p = 0.490), indicating that torsion did not compromise efficacy. However, Anterior Torsion (Torsion Index < 0) was significantly associated with a higher incidence of both immediate (43.2% vs. 14.5%, p < 0.001) and persistent (25.0% vs. 5.1%, p = 0.001) Vc symptoms. ROC analysis identified the Torsion Index (AUC 0.72-0.75) and Lesion-Habenula difference (AUC 0.76-0.84) as robust predictors for sensory side effects, significantly outperforming the standard AP ratio (AUC 0.47-0.50). CONCLUSION: Habenular torsion is a critical anatomical biomarker for predicting post-operative sensory complications. Incorporating the Torsion Index into preoperative planning allows for a personalized, anatomy-driven targeting approach, potentially enhancing the safety and efficacy of stereotactic thalamotomy.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.