The Retrosigmoid Petrosal Fissure Transpeduncular Approach to Central Pontine Lesions

BACKGROUND: The advent of improved surgical instruments and neuronavigation and descriptions of safe-entry zones have allowed neurosurgeons to resect brainstem lesions with an acceptable morbidity. The authors describe the technique of petrosal fissure dissection to the lateral transpeduricular safe-entry zone at the middle cerebellar peduncle (MCP) for resection of deep-seated central pontine pathologies. This approach allows the surgeon to obtain less cerebellar retraction and a more direct, more shallow, and shorter approach compared with the approach without opening this fissure. METHODS: An illustrative case is used to highlight the technique of dissecting the petrosal fissure to obtain a direct surgical corridor to the MCP. Anatomic dissections are used to define better the relative relationships of this fissure to the MCP and adjacent structures. RESULTS: Dissection of the petrosal fissure provides a direct trajectory to the lateral transpeduncular entry zone at the MCP and can enhance exposure of this structure, while minimizing morbidity to the corticospinal tract and cerebellum during approaches to central pontine pathologies. CONCLUSIONS: For resection of lesions within the pons via the retrosigmoid craniotomy, dissection of the petrosal fissure allows for a more direct and shorter route to the central pontine and lateral pontine lesion compared with an approach without expansion of this potential space.