Predictive Factors for Subjective Vertigo Following Cochlear Implantation: A Regional Multicenter Cohort Study of 395 Patients

IntroductionCochlear implantation (CI) is generally accepted as having a low rate of postoperative complications, but between 9.3% and 13% of cases experience vertigo postoperatively. This study aimed to examine patient, surgical, and device factors contributing toward the risk of postoperative vertigo.MethodologyA retrospective review was conducted of adult patients who underwent cochlear implant in a regional area of New South Wales from 2007 to 2018. A total of 395 cochlear implant cases were included in the final study.ResultsThe overall incidence of vertigo at 3 months of follow-up was 7.1% (n = 28/395). No difference was identified in this study between rates of postoperative vertigo between device factors, including implant make (Cochlear vs. Med-El), electrode shape (perimodiolar vs. straight), and electrode model. No significant difference was found also for surgical factors such as the number of electrode rings inserted, side of implantation, or surgical approach of tympanic ramp (round window insertion vs. cochleostomy).A higher percentage of patients with preoperative vertigo experienced vertigo postoperatively (18.4%, n = 7/38), compared with the population without preoperative vertigo (6.0%, n = 21/352) (p = 0.005). Patients with previous mastoid surgery also reported a higher rate of postoperative vertigo (20%, n = 9/45) compared with those who had not had mastoid surgery (5.43%, n = 19/350) (p = 0.006). The mean age of patients experiencing postoperative vertigo was higher than the population without postoperative symptoms (67 vs. 63).ResultsThe overall incidence of vertigo at 3 months of follow-up was 7.1% (n = 28/395). No difference was identified in this study between rates of postoperative vertigo between device factors, including implant make (Cochlear vs. Med-El), electrode shape (perimodiolar vs. straight), and electrode model. No significant difference was found also for surgical factors such as the number of electrode rings inserted, side of implantation, or surgical approach of tympanic ramp (round window insertion vs. cochleostomy).A higher percentage of patients with preoperative vertigo experienced vertigo postoperatively (18.4%, n = 7/38), compared with the population without preoperative vertigo (6.0%, n = 21/352) (p = 0.005). Patients with previous mastoid surgery also reported a higher rate of postoperative vertigo (20%, n = 9/45) compared with those who had not had mastoid surgery (5.43%, n = 19/350) (p = 0.006). The mean age of patients experiencing postoperative vertigo was higher than the population without postoperative symptoms (67 vs. 63).ConclusionThis study of a large multicenter population outlines that patient factors are more critical than surgical or device factors when considering risk factors for vertigo post-cochlear implant.