OBJECTIVETo investigate the effect and mechanism of endolymphatic sac-mastoid shunt surgery for intractable Meniere's disease of different stages according to hearing level.

METHODSData from 240 patients diagnosed with unilateral MD strictly meeting the criteria issued by Chinese Academy of Otolaryngology-Head and Neck Surgery Committee (2006) from January 1983 to January 2012 were analyzed in this study. Endolymphatic sac-mastoid shunt surgery was performed in affected ear for each patient. The evaluation of therapy followed the guidelines issued by Chinese Academy of Otolaryngology Head and Neck Surgery Committe. Vertigo control and auditory function were measured in two-year's follow-up.

RESULTSAccording to the preoperative staging of hearing, among these 240 patients, there were 12 cases in stage I (with an average hearing threshold < 25 dB), 130 cases in stage II (with an average hearing threshold of 25-40 dB), 85 in stage III (41-70 dB) and 13 cases in stage IV(with an average hearing threshold > 70 dB). Overall control rate of vertigo was 77.9% (187/240) in two-year's follow-up, with total control 49.2% (118/240) and substantial control 28.7% (69/240). The hearing was improved in 25.0% (60/240) of cases, no change in 59.2% (142/240) of cases, and worse in 15.8% (38/240) of cases. According to different stages, vertigo control rate was 83.3% (10/12) in stage I, 82.3% (107/130) in stage II, 75.3% (64/85) in stage III and 46.2% (6/13) in stage IV. Vertigo control rate of stage IV patients was significantly lower than that of stage II and III patients (χ(2) = 9.318 and 4.692, P < 0.05), while vertigo control rate of stage I, II, III patients had no significant difference with each other (P > 0.05).

CONCLUSIONEndolymphatic sac-mastoid shunt operation is an effective method in the treatment of intractable Meniere's disease, but the effect was poor in stage IV patients.