2025 Proffered Presentations
S198: SURGICAL TECHNIQUE FOR VTH AND VI NERVE PRESERVATION IN RESECTION OF MENINGIOMAS ARISING AT THE CLIVUS AND PETROUS APEX
Soichi Oya, MD1; Shunya Hanakita, MD2; Masanori Aihara, MD1; Rei Yamaguchi1; Masahiko Tosaka, MD1; 1Gunma University Graduate School of Medicine; 2Saitama Medical Center/University
Background: When removing meningiomas arising around the clivus and petrous apex, it is essential to avoid uncomfortable facial numbness and abducens nerve palsy in terms of patient quality of life, but specific methods to achieve this are not clear.
Methods: Based on 55 cases of meningioma surgery in the clivus and petrous apex region experienced by the first author, we analyzed the causes of damage in patients with new cranial trigeminal and abducens nerve palsy and discussed essential surgical techniques for preserving function.
Results: Tumor locations were petrous in 22 cases, petroclival in 11, petrotentorial in 11, posterior clinoid in 6, and clival in 5. Among facial paresthesia due to trigeminal neuropathy, severe symptoms requiring drug treatment were observed in 5 patients (9.1%). During the transpetrosal approach, we initially prioritized the tumor removal without opening the Meckel's cave. However, the incidence of severe facial paresthesia decreased after Meckel's space was opened and the tumor around the trigeminal nerve was removed first before tumor removal was initiated. Abducens nerve palsy occurred in three patients (5.5%). It is easier to preserve the abducens nerve if we find it near the brainstem side and remove the tumor by following the nerve rather than looking for it near the meningioma's attachment site. To achieve this goal, it was effective to drill the pyramidal bone and incise the presigmoid dura during the anterior transpetrosal approach to identify the normal abducens nerve in the vicinity of the brainstem behind the tumor.
Conclusions: The evolution of surgical approaches and devices has improved the outcome of meningiomas arising from the vicinity of the clivus and petrous apex. However, facial numbness and even mild abducens nerve palsy are relatively frequent and significantly reduce patients' quality of life. Our results suggest that trigeminal neuropathy is likely to occur due to nerve strangulation at the entrance to Meckel's cave, similar to the efficacy of early opening of the falciform ligament in preserving the optic nerve. Although the transpetrosal approach allows for early approach around Dorello's canal, for the purpose of preserving the abducens nerve, skull base technique that first identify the abducens nerve near the brainstem seems to be more effective.