Endoscopic retrosigmoid trans-petrosal fissure approach for vestibular schwannomas: case series

The management of vestibular schwannoma (VS) remains one of the most formidable challenges in neurosurgery owing to the eloquent nature of surrounding anatomy. Although endoscopy-assisted microsurgery has recently gained momentum in cerebellopontine angle region surgery, the feasibility of pure endoscopic technique has been rarely reported. Here we present the operative technique and preliminary outcomes of fully endoscopic retrosigmoid trans-petrosal fissure approach (ER-TPFA) for VS surgery. Clinical data of 36 consecutive cases of VS treated with the ER-TPFA from March 2021 to March 2023 were analyzed. The patients were placed in a modified lateral park-bench position, with the Dandy incision and suboccipital craniotomy performed. With the endoscopic holder, endoscopic procedures were performed using standard two-hand microsurgical techniques by one surgeon. Arachnoidal dissection of the petrosal fissure was performed for identifying the brainstem end of facial nerve and separating the tumor from the cerebellum, without brain retraction seen in traditional microsurgical technique. The tumors had an averaged size of 3.0 cm in diameter. According to the Hannover classification, nearly all the tumors were grade III-IV (97.3%). Using ER-TPFA, 33 patients (91.7%) achieved gross total resection. Anatomic preservation of the facial nerve was achieved in 35 cases, with 33 patients (91.7%) retaining a House-Brackmann score of 1-2 postoperatively. Four out of ten patients still had serviceable hearing 6 months after operation. Postoperatively, there was no post-craniotomy hematoma, cerebellar edema, and new-onset cerebellar ataxia. With a better visualization of the cerebellopontine angle region, ER-TPFA may help preserve facial nerve function and maintain high gross total resection rate while minimizing complications. We believe this retractorless technique can be a safe and effective alternative for the management of VS with satisfactory clinical results.