Endoscope-Assisted Microsurgical Removal of Trigeminal Schwannomas

The objective of this study was to demonstrate that trigeminal schwannomas (TSchs) located in different cranial fossae can be resected entirely through Meckel's cave which is expanded by the tumor by taking either an endoscope-assisted pterional epidural approach (EA-PEA) or an endoscope-assisted lateral suboccipital retrosigmoid approach (EA-LSRA). Additionally, we describe a modified classification based on Jefferson's system to determine the surgical approach.

This is a retrospective study of 19 patients with TSchs in different cranial fossae who underwent EA-PEA or EA-LSRA. According to the proposed system, lesions in the middle fossa are classified as type A, those in the posterior fossa are type B, and lesions in both fossae are type C, the same as in Jefferson classification. Our modifications begin by classifying lesions extending into different fossae. Those located primarily in the middle cranial fossa are denoted type C1, whereas one predominantly occupying the posterior cranial fossa is type C2. Lesions with extracranial extensions are classified as type D. Patients with type A, type C1, and type D lesions underwent EA-PEA, while those with type B and C2 lesions were treated through EA-LSRA.

Thirteen patients (68.4%) underwent EA-PEA and 6 (31.6%) underwent EA-LSRA. Gross total resection was accomplished in 16 patients (84.2%). No complications were observed.

Our study demonstrates that EA-PEA and EA-LSRA can lead to gross total resection in patients with complex TSchs. Endoscope assistance facilitates the visualization of residual tumor. The proposed classification system is a guide for determining the surgical approach.