Introduction: Exposure of the peri-trigonal or peri-atrial region has been challenging due to the depth of the region and vicinity of important functional cortices and white matter tracts. A cadaveric contralateral approach through the falx and precuneus cortex has been recently described [1] but has not been robustly tested in the operating room [2]. This series demonstrates the operative feasibility, efficacy and safety of a contralateral interhemispheric transfalcine transprecuneus approach to the trigonal region for a variety of pathologies.

Methods: Fourteen consecutive patients treated with the contralateral interhemispheric tranfalcine transprecuneus surgical approach were included in this study. Pre- and post-operative clinical and radiographic data points were retrospectively collected. Outcome was determined at last clinical evaluation.

Results: The mean age at the time of surgery was 39 years (range 11 to 64). Six of 14 were female. Mean follow-up was 98 days (range 6 to 531). Pathology included six arteriovenous malformations, four gliomas, two meningiomas, one metastatic lesion and one grey matter heterotopia. Average lesion size was 25 cc (range 1 to 132). One lesion was subtotally resected; of the remaining 13, greater than or equal to 95% resection was achieved in all cases and gross total resection was achieved in 7 of 13. There was one approach-related complication which was temporary. One patient expired due to complications of underlying disease; the other 13 patients had a good (GOS 4 or 5) outcome.

Conclusions: The contralateral interhemispheric transfalcine transprecuneus approach offers numerous advantages including a wider operative corridor, minimal ipsilateral brain manipulation, and better intraoperative navigation and working angles due to decreased perilesional parenchymal retraction or transgression. This novel approach is demonstrated to be safe and efficacious in a series of 14 consective patients.

Patient Care: This study provides an operative approach to a difficult location that in correctly selected patients may avoid surgical approach-related morbidity.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Identify a new operative corridor to the posterior medial cerebral hemisphere, 2) Estimate the safety profile and risks of this approach, 3) Consider including this approach in their operative armamentarium for appropriate patients.

References: [1] Wang, S., A. Salma, and M. Ammirati, Posterior interhemispheric transfalx transprecuneus approach to the atrium of the lateral ventricle: a cadaveric study. J Neurosurg, 2010. 113(5): p. 949-54. [2] Goel, A., Transfalcine approach to a contralateral hemispheric tumour. Acta Neurochir (Wien), 1995. 135(3-4): p. 210-2.