Outcomes of attempted hearing preservation after cochlear implantation (HPCI): a prognostic factor (PF) systematic review of the literature.

Abstract

Objective: There's a need to highlight prognostic factors (PFs) determining hearing preservation in cochlear implantation (HPCI), as currently there is large variability in outcomes. Given the potential benefits of HPCI, it is important to understand the factors influencing this variation. We apply a novel methodology to outline and assess the accuracy of prognostic factors reporting for HPCI.

Data sources: A preferred reporting item for systematic reviews and meta-analyses compliant systematic review, searches applied to Medline, EMBASE, and Cochrane.

Study selection: The CHARMS-PF tool assessed the strength of PF study designs.

Data extraction: The QUIPS tool assessed for risk of bias.

Data synthesis and results: Ninety-two papers were suitable for data extraction. The domain's preoperative hearing loss, size of the round window opening, round window accessibility, surgical insertion speed and route (Round window or cochleostomy), electrode length and type were identifiable exploratory PFs for HPCI. Overall, the study's heterogeneity and risk of bias precluded reporting by forest plots and meta-analysis.

Conclusions: Most exploratory PF studies for HPCI are hindered by the risk of bias. This systematic review identifies potential independent PFs which should be measured, and adjusted for, in future confirmatory studies using a multivariate analysis. This would determine the independent prognostic effects associated with HPCI while facilitating prognostic model development and the predict individual HPCI.