Analysis of Pontine cavernous malformation resection based on 3D microanatomical study

Pontine cavernous malformations (PCMs), the most common subset of brainstem cavernous malformations (BSCMs), carry a high surgical risk. This study analyzes surgical strategies based on anatomical and clinical considerations. Ten Klingler-prepared human brainstem specimens underwent microdissection to map critical pontine nerve fiber tracts. Ten additional specimens simulated surgical approaches to delineate safe exposure ranges, followed by validation in clinical cases. PCMs surgical regions were categorized as ventral, ventrolateral, and dorsolateral. The trigeminal nerve subdivides the ventrolateral pons into superior and inferior trigeminal quadrangular spaces, which serve as safe surgical entry zones. In the dorsolateral region, the interpeduncular sulcus (IPS) functions as a key landmark; when combined with the trochlear nerve, which defines the superior boundary, the IPS forms a safe surgical corridor. Systematic fiber tract analysis clarified the three-dimensional spatial relationship between the corticospinal tract (CST) and transverse pontine fibers, providing an anatomical basis for longitudinal pontine myelotomy design. The subtemporal transtentorial approach provides optimal exposure and lesion access for ventral/ventrolateral PCMs superior to the trigeminal nerve root. PCMs inferior to or extending superiorly across the trigeminal nerve root demonstrate better surgical suitability via the retrosigmoid approach. For dorsolateral PCMs, the extreme lateral supracerebellar infratentorial approach via the IPS corridor demonstrated anatomical safety. Standardized preoperative imaging combined with intraoperative electrophysiological monitoring and neuronavigation enhances resection precision and safety. Anatomical landmarks remain critical for guiding the selection of optimal surgical entry points and minimizing nerve fiber bundle injury.