Outcome analysis in 31 cases with Mondini malformation who underwent cochlear implantation with preoperative evaluation using electrically evoked auditory brainstem responses

WANG Bin; CAO Keli; WEI Chaogang; WANG Yi; LI Huan

doi:10.3969/j.issn.1672-2922.2017.01.009

Abstract：Objective To investigate the hearing and speech rehabilitation outcomes in the cases with Mondi-ni malformation underwent cochlear implantation with preoperative evaluation using electrically evoked auditory brainstem responses (EABR). Methods Thirty-one cases with Mondini malformation underwent cochlear implanta-tion in our hospital from the year 2012 to 2015. The audiologic testing, preoperative EABR, surgical technique, and postoperative neural response telemetry (NRT) results in these cases were analyzed retrospectively. The hearing and speech rehabilitation ability were evaluated using categories of auditory performance (CAP) and speech intelligibili-ty rating (SIR) scores. Another 20 cases of cochlear implantation with normal cochlea served as the normal control group. Results Thirty-one cases with Mondini malformation presented with profound sensorineural hearing loss, 14 cases of which showing no residual hearing. Seven cases in control group showed no residual hearing. All cases demonstrated presence of EABR response preoperatively. The patients with no residual hearing were implanted with different types of electrodes. Four cases had cerebrospinal fluid (CSF) gusher during procedure, which was controlled by plugging with temporaries muscle, and no postoperative complications occurred. All Mondini malfor-mation patients gained hearing postoperatively. The inducible rate of NRT on the boot day was 41.94%which was lower than that in the control group (which was 95%). About 6 month postoperatively the average T value was 171.37 ± 13.14CL in Mondini group versus 145.34 ± 17.43CL in control group (P<0.05); the dynamic range was 33.24 ± 10.73CL in Mondini group versus 43.55 ± 15.36CL in control group (P<0.05). Postoperative follow-up from 6 months to 4 years show that the Mondini group has the average CAP scores of 6.13±1.15 (7.12±0.80 in con-trol) and SIR scores of 3.05±0.62 (4.03±0.91 in control),with significant difference (P<0.05) compared to the con-trol group. Conclusions Cochlea implantation can be performed in patients with bilateral profound hearing loss in Mondini malformation, and even for those without residual hearing, if preoperative EABR is present. Significantly improved hearing and speech were achieved, though the postoperative hearing and speech rehabilitation outcomes were poorer in Mondini malformation than that with normal cochlear structure.