Endoscope-Assisted Microsurgery for Posterior Fossa Skull Base Meningioma Surgery: Technique and Results.

[BACKGROUND AND OBJECTIVES] Surgery of posterior fossa meningiomas is extremely challenging even for experienced skull base surgeons because of the close proximity to cranial nerves and tight spaces. Endoscope-assisted surgery for posterior fossa meningiomas can enable a high degree of tumor resection even when using small approaches. This study describes the advantage of endoscope-assisted microneurosurgery in resection of posterior fossa skull base meningiomas and the clinical outcome.

[METHODS] All endoscope-assisted surgeries for resection of posterior fossa meningiomas performed between 2002 and 2016 in our department were retrospectively analyzed. For data acquisition, the patient files were used. Tumor size and extent of resection were evaluated on pre- and postoperative magnetic resonance imaging. The value of endoscope assistance was assessed according to the intraoperative videos and the surgical notes. Complications and long-term outcomes were evaluated.

[RESULTS] We identified 39 female and 10 male patients. The mean age of the patients at the time of surgery was 55 years, ranging from 25 to 78 years. The mean follow-up was 93.8 months. A total of 41% of the tumors were large to giant. The retrosigmoid approach was used in most patients (45). A gross total resection could be achieved in 38 patients (78%). In 11 patients (22%), a near total resection was performed. In 27 patients (55%), a hidden residual tumor, which could not been visualized with the operating microscope, was identified with the endoscope. In 6 patients (22.2%), the internal auditory canal was visualized, in 9 patients (33.3%), the Meckel's cave was visualized, and in 5 patients (18.5%), both were visualized under endoscope assistance. In 26 of those patients (96.3%), the residual tumor was resected under endoscopic view.

[CONCLUSION] Endoscope-assisted surgery for posterior fossa skull base meningiomas enables a high degree of tumor resection, avoids more invasive skull base approaches, and reduces the amount of cerebellar retraction.