PubMed2004
OBJECTIVE: Investigate whether the cochleostomy is a possible port of entry for pneumolabyrinth and a resulting vertigo in patients provided with a cochlear implant. STUDY DESIGN: Retrospective case review. SETTING: Ludwig-Maximilians University of Munich, Hospital Grosshadern. PATIENT: 62-year-old patient who underwent implantation of a HiFocus II cochlear implant with positioner from Advanced Bionics (CLARION). Eight months postoperatively, the patient reported rotatory vertigo and right-side tinnitus after he had blown his nose harder than usual during an episode of rhinitis. INTERVENTIONS: Preoperative and postoperative testing of both the petrosal bone with a CT scan and of balance function. MAIN OUTCOME MEASURE: Air inclusion in the labyrinth. RESULTS: In contrast to the preoperative high resolution computed tomography (CT) scan, air inclusion was seen in the labyrinth during the episode of vertigo. At the same time, balance function tests with Frenzel glasses revealed both spontaneous and provoked horizontal nystagmus to the right side. At follow-up 8 weeks later, the level of vertigo had significantly decreased. Twelve months later, the control CT showed the cochlear implant positioned correctly and no visible air in the labyrinth. CONCLUSION: It is known that placement of the HiFocus II with Positioner from CLARION requires a relatively large cochleostomy of 1.5 mm. Moreover, in the connective tissue seal between the electrode and the positioner, the latter reaches into the tympanic cavity, and this is possibly the weak point. Further investigation will be needed to determine whether the large cochleostomy with the HiFocus II with positioner increases the predisposition to labyrinth dysfunction.