The influence of electrode array design, scalar dislocation and insertion technique on postoperative vertigo in CI surgery - a prospective study.

Objectives: This study aimed to examine the effect of electrode array design, insertion angle, scalar position, and insertion technique on the occurrence of postoperative subjective vertigo following cochlear implant (CI) surgery using questionnaires in conjunction with objective vestibular functional measurements.

Materials and methods: We prospectively evaluated subjective vertigo using the Dizziness Handicap Inventory (DHI). Additionally, we performed videonystagmography, video head-impulse tests, and vestibular-evoked myogenic potentials to assess the objective vestibular function preoperatively, at four weeks and 12 months after CI. These results were compared with those of postoperative imaging using digital volume tomography.

Results: Postoperative vertigo was observed in 2 out of 62 patients (3%). Cochleostomy (n = 8) did not lead to an increase in postoperative vertigo. Functional diagnostics revealed abnormalities in up to 23% of patients without subjective dizziness. In our patient cohort, neither electrode array dislocation nor increasing insertion depth was associated with an increase in postoperative vertigo.

Conclusion: Both postoperative vertigo occurrence and electrode array dislocation rates have significantly decreased due to the optimized atraumatic electrode array design and improved surgical insertion techniques. Neither dislocation nor cochleostomy appeared to induce vertigo but the sample size was too small to draw definitive conclusions.