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DOI: 10.1055/s-0036-1592529
Surgery of Large and Giant Vestibular Schwannoma: Its Dilemma
Objective: Surgical results of larger tumor, especially cystic vestibular schwannoma are reported to be unfavorable comparing to those of small tumors. We analyzed retrospectively facial nerve outcome in larger tumors considering extent of removal, consistency, age, and size.
Patients and Methods: From 2000 to 2014, a total of 250 vestibular schwannomas were removed. Among them, the number of larger tumors having maximum diameter at CP angle (MaxCPA) of over 30 mm was 99 (40%). Complete tumor removal was intended in all cases via retrosigmoid approach. Small piece was left, however, if severe adhesion to the facial nerve was found and monitoring showed poor response during dissection.
Results: Max CPA ranged from 30 to 60 mm (mean: 37.3). 44 tumors (44%) were cystic and 55 (56%) were solid. Complete tumor removal could be achieved in 51 (53%). Good facial nerve function (HB 1 or 2) was obtained in 89 (89.9%). It reached to 94.1% for completely removed tumors and 85.4% for the others. Multiple logistic regression analysis revealed the age, side, consistency were not related to the facial outcome. Only the degree of removal and size were the significant prognostic factor (p < 0.05). Recurrence was found in five cases and further treatment was necessary in three cases. All of them were subtotal removal cases.
Conclusion: Total or near-total removal with functional preservation is the goal. Incomplete removal was another factor for poor facial function besides giant size. This could be explained by the fact that tumor removal was ended incomplete due to severe adhesion or fragility of the nerve. Less aggressive surgery would be advocated for giant tumors with severe adhesion, although recurrence would increase.