Facial Nerve Outcome and Results in Hypervascular Large Vestibular Schwannomas: Our Personal Experience in A Series of 32 Cases.

Abstract BackgroundVestibular schwannomas (VS) are usually hypovascularized. Large VS with unusual vascular architecture are defined hyper-vascular (HVVS); excessive bleeding during microsurgery has negative impact on results. Methods Thirty-two consecutive patients were operated on for HVVS (Group-A). Results were compared with those of 25 patients (Group-B) operated on for large low-bleeding VS. Tendency to bleed and adherence of capsule to nervous structures were evaluated by reviewing video records. Cisternal facial nerve (FN) position was reported. Microsurgical removal was classified as total, near-total, subtotal or partial and MIB-1 index evaluated in all. FN results were classified according the House-Brackmann scale.Results Mean tumor diameter was 3,99cm in Group-A and 3,67 in Group-B; mean age was 42,3 and 58,1 years, respectively. Mean ASA class of Group-A was 1,72 versus 2,48 of Group-B (p<0,001). Total-NT resection was accomplished in 71,9% of HVVS versus 80,0% of Group-B. Tight capsule adhesion was observed in 68,7% HVVS versus 56,0% low-bleeding ones. Mean MIB-1 was 1,25% and 1,08%, respectively.Anterior-superior position of FN was observed in 48,6% of HVVS versus 32,0% of low-bleeding tumors (p<0,05). FN anatomical preservation was possible in 81,2% of Group-A versus 100% of Group-B (p<0,05); 62,5% of HVVS had HBI-II FN outcome versus 96,0% of low-bleeding (p<0,01). In Group-A 25,0% experienced postoperative complications versus 8,0% of Group-B (p<0,05). Recurrence/re-growth was observed in 7 HVVS versus 1 low-bleeding (p<0,05).Conclusions Microsurgery of large HVVS was associated with higher complication and recurrence/re-growth rate and poorer FN outcome, especially in cases with tight capsule adhesion.