Hearing preservation in acoustic neuroma surgery: importance of adhesion between the cochlear nerve and the tumor.
OBJECTIVE
To evaluate the possible prognostic factors for hearing preservation, the authors retrospectively reviewed the results of 30 consecutive acoustic neuroma operations in which hearing preservation was attempted, in a total series of 63 acoustic neuromas.


METHODS
Intracanalicular tumors or those that extended less than 3 mm outside the porus acusticus (10 cases) were resected via the middle fossa approach. The retrosigmoid approach was used for tumors exceeding the limits for the middle fossa approach (20 cases). Overall, hearing was preserved (pure tone average < or = 50 dB and speech discrimination score > or = 50%) in 21 patients (70%). There were 11 patients with severe adhesion between the cochlear nerve and tumor capsule, and 19 without. Hearing was preserved postoperatively in only two (18.2%) of 11 patients with severe adhesion, whereas all 19 without severe adhesion had hearing preservation.


CONCLUSIONS
The presence or absence of severe adhesion in the interface between the cochlear nerve and the tumor might be the most significant prognostic factor for hearing preservation postsurgery.
Moriyama
Takuzou
T
Carolina Neuroscience Institute and Carolina Ear Research Institute, Raleigh, North Carolina 27609, USA. Mtakuzo@minos.ocn.ne.jp
Fukushima
Takanori
T
Asaoka
Katsuyuki
K
Roche
Pierre-Hugues
PH
Barrs
David M
DM
McElveen
John T
JT
D000328:Adult; D000368:Aged; D003056:Cochlear Nerve / Q000503:physiopathology / Q000601:surgery*; D005154:Facial Nerve / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006311:Hearing Disorders / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications* / Q000503:physiopathology / Q000601:surgery*; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index; D000267:Tissue Adhesions / Q000150:complications* / Q000503:physiopathology / Q000601:surgery*