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Outcomes of Revision Cochlear Implantation.

OBJECTIVES/HYPOTHESIS
This study aims to 1) report revision cochlear implantation (CI) rates at a high-volume CI center, 2) describe classifications for revision CI, 3) analyze audiologic and surgical outcomes in patients who undergo revision CI, and 4) describe a new subcategory of soft failures, named presumed soft failures.


STUDY DESIGN
Retrospective case series.


SETTING
Tertiary care otologic center.


PATIENTS
Adults and children undergoing revision CI from 2005 to 2015.


MAIN OUTCOME MEASURE
Type and etiology of CI failure, preoperative, and postoperative outcomes (audiologic, surgical).


RESULTS
During the study period, 1,469 CI surgeries were performed with a total of 81 (5.51%) revision cochlear implantations, 64 of these meeting inclusion criteria with adequate follow up and clear indications for revision surgery. The most common indication for revision surgery was hard failure (53.1%), followed by soft failure (29.7%), and medical/surgical failure (17.2%). 78.1% (50/64) of revision CI patients showed improvement postoperatively (defined as 15% improvement of speech perceptions scores or improvement of aversive symptoms, according to the 2005 consensus statement guidelines). Hard failures showed improvement in 85.3% (29/34) of cases, medical and surgical failures showed improvement in 72.7% (8/11) of cases, and soft failures showed improvement in 68.4% (13/19) of cases. There was a statistically significant difference in percentage of adult versus pediatric patients by failure subtype, with 84.2% of soft failure patients classified as adults (18 or older) at the time of revision surgery compared with 50% and 36.3% for hard failure and medical/surgical failure patients, respectively (p = 0.02). Similarly, there was a trend, though not statistically significant, towards older age in the soft failure group compared with hard and medical/surgical failure groups (median 43 yr versus 18 and 16, respectively). Within the soft failure group there was a subset of patients that failed to show improvement in audiologic performance or experienced continued aversive symptoms referred to as "presumed soft failures." These patients, by definition, experienced worse outcomes after revision surgery (p < 0.05) and trended towards older age (43 versus 31 yr) and longer time from initial to revision surgery (27.3 versus 24.7 mo) when compared with true soft failures.


CONCLUSIONS
The majority of patients improved after revision CI surgery; patients with hard failure demonstrated the highest percentage with improvement, while those with soft failures had worse outcomes. The presumed soft failure group may represent a unique etiology for CI failure that warrants further investigation given worse outcomes after revision surgery.