Introduction: Multicompartmental non-vestibular schwannomas are a rare (< 1%) and complex entity which entail a surgical challenge for skull base surgeons. Their extension into different intracranial compartments such as Meckel´s cave, middle and posterior fossa among others, requires an effective surgical strategy. Traditionally, these lesions have been managed with classical skull base approaches, achieving gross total resection (GTR) rates around 70-80%.

Objectives: Recent publications have suggested a more straight forward route for these tumors with an endoscopic approach. We analyse and assess its feasibility from a purely endoscopic endonasal approach (EEA) as well as a combined approach (EEA + retrosigmoid) for cases with tumor extension into the posterior fossa.

Methods: A retrospective analysis was performed on 6 patients with multicompartmental non-vestibular schwannomas who underwent an EEA (± retro sigmoid approach) between 2017 and 2021. The extent of resection, clinical outcome and surgical morbidity were analysed.

Results: 6 patients with multcompartimental non-vestibular schwannomas were analysed: 5 trigeminal schwannomas and an extremely rare carotid canal sympathetic plexus schwannoma. 3 patients had dumbbell-shape tumors, 2 of them located in the middle and posterior fosa and 1 located at Meckel´s cave with extension into the maxillary subcutaneous region through the infraorbital canal; 1 patient presented with tumor at the petroclival region, petrous apex and parapharyngeal space and 2 patients had tumors affecting the middle fosa, Meckel´s cave, pterigoid fossa and/or sphenoid sinus. Tumor size was over 3.5 cm in all cases (> 4 cm in 3 patients). In 2 patients a combined EEA + retrosigmoid approach was performed in 2 stages and 4 patients were managed with a purely EEA. GTR was achieve in a 100% of the patients. There were not CSF leaks.

Conclusions: EEA (± retrosigmoid approach) provides an adequate and effective surgical strategy for the management of multicompartmental non-vestibular schwannomas.