A Series of 112 Fully Endoscopic Resections of Vestibular Schwannomas

Abstract

We report a consecutive series of 112 patients with unilateral vestibular schwannoma (VS) having undergone fully endoscopic resection of their tumors in the period from October, 2001 to January, 2005. Patients' outcomes were evaluated especially with regards to cochlear nerve (hearing) preservation, facial nerve preservation, postoperative complications and completeness of the resection. The patient population consisted of 112 consecutive cases with unilateral, "de novo" VS(s); patients with neurofibromatosis type 2 (NFT2) or with a recurrent tumor were excluded from this study. Tumors ranged in size from 0.6-5.7 cm, most tumors were less than 3 cm in diameter (mean: 2.6 cm). This shift towards smaller and also less symptomatic tumors may be due to an increase in the awareness of patients and earlier detection of their tumors (MRI era). Tumors were removed via 1.5-cm "keyhole" retrosigmoid craniotomies. Utilizing the fully endoscopic technique, 106/112 (95%) tumors were completely removed; subtotal removal was performed in 6/112 (5%) patients in an attempt to preserve their hearing. Anatomic preservation of the facial nerve was achieved in all of the patients and of the cochlear nerve in 83/101 (82%) hearing ears. Functionally, measurable hearing (serviceable/some) was preserved in 59/101 (58%) cases who had either "serviceable" or "some" hearing preoperatively, 2 patients who had "some" hearing preoperatively had an improvement that was more than 30 db in their hearing postoperatively. There were no major neurological complications such as quadriparesis, hemiparesis, bacterial or aseptic meningitis, lower cranial nerve deficits, or deaths. From our experience, we conclude that the endoscope is ideally suited for a minimally invasive approach for the resection of vestibular schwannomas.

Minimally Invasive Endoscopic and Endoscopy-Assisted Microsurgery of Vestibular Schwannoma

“…The first report of fully endoscopic resection of vestibular schwannoma was by Shainian and coworkers in 2004 (Shahinian et al 2004). Kabil and Shahinian in 2006 have presented 112 fully endoscopic procedures performed via 1.5 cm retrosigmoid craniotomy with excellent results. 95% tumors were completely removed.…”

“…Some or serviceable hearing was preserved in 58% of preoperative cases. There were no major neurological complications (Kabil & Shahinian, 2006). Recently, the first high-definition (HD) cameras designed for endoscopic surgery have been developed.…”

“…Compared to the static imaging obtained by the surgical microscope, endoscopes of varying diameter, length and angulation allow surgeons to dynamically rotate and alter their perspective of the surgical field to compensate for the two-dimensional view. This amounts to a greater appreciation of the three-dimensional relationships between the tumor and the surrounding structures (Kabil & Shahinian, 2006). Furthermore novel binocular three-dimensional endoscopical technique during skull base surgery facilitating depth perception has been described recently.…”

“…However this potential problem was solved with introduction of either rigid pneumatic holding arms for the endoscope or freehand endoscopic technique with the endoscope being moved and held by a second surgeon. Both techniques were shown to be safe at allowing bimanual surgical dissection (Eby et al 2001, Jarrahy et al 2002a, Jarrahy et al 2002b, Schroeder et al 2004, Kabil & Shahinian, 2006, de Vitiis et al 2007). Another important step forward was the introduction of an irrigation system, eliminating the time consuming and unsafe practice of removing and reinserting the endoscope.…”

“…Among the main drawbacks of endoscopic surgery of vestibular schwannoma is the risk of injury of very sensitive and critical structures of the cerebellopontine angle as the endoscope does not see the instrument used before it passes in front of the lens. Thus it is mandatory to achieve synchronized, in-and-out movements of the endoscope together with the instruments (Jarrahy et al 2002a, Jarrahy et al 2002b, Kabil & Shahinian, 2006, de Vitiis et al 2007). Using the video-endoscopy assisted microsurgical technique the handling of instruments is controlled by the microscope befor e comin g in fr on t of t h e len s of t h e endoscope , Miyazaki et al 2005, Betka et al 2010, Gerganov et al 2010.…”