Article
Subtotal resection of large vestibular schwannomas allows excellent functional outcomes comparable to small schwannomas
Die subtotale Resektion großer Vestibularisschwannome ermöglicht ein excellentes funktionelles Outcome vergleichbar zu kleinen Schwannomen
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Published: | May 30, 2008 |
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Objective: Complete resection is the primary goal in vestibular schwannoma (VS) surgery. However, radical surgery is compromised by an increased incidence of hearing loss and facial paresis dependent on tumor size. For this reason, complete resection is not enforced in patients with intense adhesions of the tumor to the cranial nerves. The aim of our retrospective analysis was to compare the outcomes of hearing and facial nerve function in two groups of patients: (A) patients with VS larger or equal to 30 mm extrameatal diameter that were resected subtotally, (B) patients with tumors smaller than 20 mm that were resected completely or subtotally.
Methods: Tumor size, degree of resection, facial nerve function (House-Brackmann-Score, HB), hearing (Gardner-Robertson-Score, GR) and incidence of residual tumor progression was documented in 151 patients that received VS surgery between 01/2002 and 09/2007 (personal series of 2 neurosurgeons). Mean follow-up was 21 months (range 1-72). Statistical comparison between groups A and B was performed with the Whitney Mann Rank Sum test.
Results: In both groups A (n=50, mean tumor size 37 mm) and B (n=49, mean tumor size 16 mm), we found an identical median HB of 1 preoperatively (75%-CI [1;1]), postoperatively (75%-CI [1;2]), and after one year (75%-CI [1;1]). There were 3 patients with HB 4 or 5 after 1 year in group A, and 2 in group B.
GR scores of patients with preoperatively serviceable (GR 1-3) hearing were identical in both groups with a median of 2 (75%-CI [2;3]) preoperatively, and each 3 (75%-CI [2;3]) postoperatively and after 1 year. Serviceable hearing was preserved in 57% of the patients in group A and in 64% in group B. Non-parametric testing did not reveal any difference between both groups.
During follow-up, 6 patients of group A experienced regrowth of the VS, which was treated by radiosurgery without complications.
Conclusions: In conclusion, subtotal resection of large VS allows excellent functional results similar to small VS with high preservation rates of hearing and facial nerve function. In our opinion, this advantage justifies the risk of regrowth in these patients, which can be controlled by radiosurgical means.