Hearing preservation and facial nerve outcomes in vestibular schwannoma surgery: results using the middle cranial fossa approach.
OBJECTIVE
To evaluate surgical results using the middle cranial fossa approach for hearing preservation vestibular schwannoma surgery.


METHODS
Retrospective case review.


METHODS
Tertiary referral academic center.


METHODS
Seventy-three consecutive patients with vestibular schwannoma operated on using the middle cranial fossa approach between February 1999 and February 2005.


METHODS
The tumors were removed via the middle cranial fossa approach with modifications to improve exposure. Standard auditory brainstem and facial nerve monitoring were used.


METHODS
Pre- and postoperative hearing measures and facial function, tumor size, and postoperative complications. Hearing status was categorized into Classes A, B, C, and D as described by the American Academy of Otolaryngology-Head and Heck Surgery "Guidelines for the Evaluation of Hearing Preservation in Acoustic Neuroma, 1995."


RESULTS
Thirty-four patients presented with Class A hearing preoperatively. Among patients presenting with Class A hearing, a total of 27 (80%) maintained Class A or B hearing postoperatively. Of these, 21 (62%) remained in Class A, 6 (18%) deteriorated slightly to Class B, and 7 (20%) deteriorated to Class D postoperatively. Twenty-eight patients presented with Class B hearing preoperatively. Of these, 18 (64%) remained in Class B, 3 (11%) deteriorated to Class C, and 7 (25%) deteriorated to Class D. Three patients had Class C hearing preoperatively. Of these, 2 (66%) remained in Class C and 1 (33%) deteriorated to Class D. Eight patients presented in Class D and one of these improved to Class C postoperatively. Overall, 62 patients presented with useful (Class A or B) hearing and 45 (73%) remained in Class A or B. Nineteen patients had tumors larger than 10 mm in greatest dimension and had Class A or B hearing preoperatively. Of these, 11 (58%) retained Class A or B hearing postoperatively. At 4 months or greater follow-up, facial nerve outcome were excellent in 96%: House-Brackmann Grade I in 61 (85%), Grade II in 8 (11%), and Grade III in 3 (4%). There were no Grade IV, V, or VI results on final follow-up. Six (8%) patients developed cerebrospinal fluid leaks.


CONCLUSIONS
By achieving excellent exposure and using meticulous microsurgical technique, it is possible to resect small vestibular schwannomas via the middle fossa approach, with preservation of hearing at excellent or preoperative levels in the majority of patients, with excellent or satisfactory facial nerve outcomes in 96% of patients.
Arts
H Alexander
HA
Division of Otology/Neurotology, Department of Otolaryngology-Head & Neck Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA. aarts@umich.edu
Telian
Steven A
SA
El-Kashlan
Hussam
H
Thompson
B Gregory
BG
D001300:Audiometry, Evoked Response; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology*; D035301:Cranial Fossa, Middle; D005154:Facial Nerve / Q000502:physiology*; D005158:Facial Paralysis / Q000209:etiology / Q000517:prevention & control*; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D009464:Neuroma, Acoustic / Q000601:surgery*; D013506:Otologic Surgical Procedures / Q000379:methods*; D011183:Postoperative Complications / Q000517:prevention & control; D012044:Regression Analysis; D012189:Retrospective Studies; D016896:Treatment Outcome