Considerations to improve the quality of cochlear implant surgery using measurements on postoperatively measured changes in the vestibular system

Abstract

Introduction: The vestibular system is at risk of damage during cochlear implantation, especially during electrode insertion. It is important to choose the best CI electrode according to the patient´s condition considering the preoperative status of the vestibular system.Objectives: To monitor the quality of the cochlear implant surgeries by evaluating:(1) possibility of vestibular damage following cochlear implantation surgery using two different types of implant electrode arrays (straight and perimodiolar) and formulate a recommendation on choosing the most appropriate type of array design;(2) provide guidance on how experienced surgeons can assist in improving the skills of more junior surgeons to minimize loss of vestibular function.Study design: Retrospective study.Method: Review of our cochlear-implant databank yielded 997 surgeries between January 2012 and December 2013. Postoperative videonystagmography records were analysed for patients who received either a Nucleus Contour Advance or Nucleus Slim Straight with preoperative and postoperative results at 4–6 weeks. Self-report records were available where patients had postoperative symptoms of vertigo. The degree of loss of vestibular function when surgery was performed by a senior or junior surgeon evaluated.Results: Of the 550 patients who had received a Nucleus implant, 85 recipients fulfilled the inclusion criteria. This study showed a significant difference in the value indicating vestibular changes for the implanted ear. There was a trend for slightly poorer postoperative vestibular function in patients with contour advance electrode compared to slim straight electrode. The junior group had more cases of diminished postoperative vestibular function than the senior group.Conclusion: Our study indicates that the design of the cochlear implant electrodes used, may affect function of the vestibular organ. We recommend using slim and lateral wall electrode in case of only functioning vestibular organ. Senior surgeons should assist junior surgeons while performing the cochlear implant surgery.