• Luciano Mastronardi, Guglielmo Cacciotti, Raffaelino Roperto, Ettore Di Scipio, Maria Pia Tonelli, and Ettore Carpineta.
• Department of Neurosurgery, San Filippo Neri Hospital-ASL Roma 1, Rome, Italy. Electronic address: mastro@tin.it.
• World Neurosurg. 2016 Oct 1; 94: 174-180.

ObjectiveTo investigate the variation in the position and course of the facial nerve (FN) in patients undergoing vestibular schwannoma (VS) microsurgery by the keyhole retrosigmoid approach and the relationship between FN position and postoperative facial results.MethodsThe series consists of 100 patients who underwent VS microsurgery during a 5-year period in whom the position and course of the FN could be confirmed by direct stimulation. The course of the FN was classified into 4 patterns according to its position: anterior (ventral) surface of the tumor (A), anterior-superior (AS), anterior-inferior (AI), and dorsal (D).ResultsThe distribution of patterns was as follows: AS in 48 cases, A in 31, AI in 21, and D in zero. For tumors <1.5 cm, the AS pattern was most common (68.4%). For tumors ≥1.5 cm, the proportion of A and AI positions increased (31.4% and 25.5%). Significant differences were observed between position and course patterns of the FN and postoperative nerve results. Patients with AS and AI patterns had better House-Brackmann FN function compared with patients with the A pattern (P < 0.05). Moreover, in tumors >3.0 cm, the FN tended to adhere strongly to the tumor capsule, and postoperative facial deficits were more frequent (P < 0.05).ConclusionsThe AS pattern was most common for smaller VSs. The A position and course and adhesion of the FN to the tumor capsule were the 2 factors most strongly associated with worse postoperative FN result.Copyright © 2016 Elsevier Inc. All rights reserved.

29 keywords...

hide…