Hearing preservation in retrosigmoid approach of small vestibular schwannomas: prognostic value of the degree of internal auditory canal filling.
OBJECTIVE
To assess the contribution of preoperative radiologic appearance of vestibular schwannoma (VS) on the magnetic resonance imaging in constructive interference in steady-state sequences and demonstrate if the degree of the internal auditory canal (IAC) filling is correlated with hearing and facial preservation.


METHODS
A group of 278 patients who underwent VS surgery in a tertiary referral center.


METHODS
Retrosigmoid approach surgery.


METHODS
Patients were classified in 4 groups according to the percentage of IAC filling on the preoperative magnetic resonance imaging as Group IAC 1(IAC empty or filled <25% and with free fundus), Group IAC 2 (IAC filled from 25% to 50% with free fundus), Group IAC 3 (IAC filled from 50% to 75% with free fundus), and Group IAC 4 (complete filling of the IAC without fundus obliteration).


RESULTS
A good correlation was observed between the IAC classification and the rate of hearing and facial preservation. The global rate of postoperative facial palsy was 10.4%. The global rate of hearing preservation in 213 patients with preoperative hearing class A and B was 40.8%. Regression analysis showed that the degree of lateral extension of the VS in the IAC was a strong predictor of hearing preservation ( p < 0.04).


CONCLUSIONS
The retrosigmoid approach yields good facial outcomes in selected patients with possible hearing preservation. In case of patient with small tumor and IAC empty or filled less than 75% and with free fundus, surgery is the treatment of choice for patients with serviceable hearing and the desire to retain it.
Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Département d'Otologie et d'Otoneurotologie, Pierre-Bénite, France. stephane.tringali@chu-lyon.fr
Stéphane
S
Tringali
Chantal
C
Ferber-Viart
Carine
C
Fuchsmann
Guillaume
G
Buiret
Sandra
S
Zaouche
Christian
C
Dubreuil
D001301:Audiometry, Pure-Tone; D003390:Cranial Nerve Neoplasms / Q000601:surgery*; D007758:Ear, Inner / Q000473:pathology*; D005155:Facial Nerve Diseases / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D000159:Vestibulocochlear Nerve / Q000601:surgery*