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Hearing Preservation Outcomes and Prognostic Factors in Acoustic Neuroma Surgery: Predicting Cutoffs.

OBJECTIVE
To investigate the outcomes of hearing preservation surgery (HPS) for acoustic neuroma and quantify tumor and patient characteristics predictive of hearing preservation after surgery.


STUDY DESIGN
Retrospective study.


SETTING
Tertiary referral center.


PATIENTS
A total of 100 consecutive patients diagnosed with acoustic neuroma from 2000 to 2012.


INTERVENTION
Hearing preservation surgery through microscopic retrosigmoid approach combined with a retrolabyrinthine meatotomy.


MAIN OUTCOME MEASURE
Pre- and postoperative hearing stratified according to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) and the Tokyo classifications. The most accurate cutoff was identified for each tumor and patients' variable affecting the outcome by calculating the Youden index. A multivariable analysis was undertaken at these cutoffs to identify prognostic factors for hearing preservation.


RESULTS
Preoperative hearing class was preserved after surgery in 31% (AAO-HNS), and 39% (Tokyo classification) of patients. According to the AAO-HNS classification, the tumor size in the cerebello-pontine angle, pure-tone average (PTA), and speech discrimination score cutoffs for predicting good postoperative hearing function were 7 mm, 21 dB, and 90%, respectively. With the Tokyo classification, only the PTA cutoff differed, with 27 dB. On multivariable analysis, tumor size and PTA were independent prognostic factors for postoperative hearing with high model's goodness of fit (area under the curve  = 0.784; 95% CI = 0.68-0.88 and area under the curve  = 0.813; 95% CI = 0.72-0.90), according to both the hearing classifications.


CONCLUSIONS
The estimated cutoffs for tumor size and PTA were independently associated with HPS. These factors should be prospectively investigated before they are adopted as selection criteria for HPS.