Meningitis in cochlear implant recipients: The North American Experience

Introduction: Until recently, postimplant meningitis was infr-equently reported and felt to be uncommon. However, in the spring of 2002, there was a sudden increase in the number of reported cases of postimplantation meningitis in both Europe and North America. Objective: Because complications of surgery often tend to be underreported, we decided to survey all cochlear implant cen-ters in North America to determine the true incidence of postimplant meningitis and to learn more about the demographics and risk factors. Study Design: We conducted a prospective study. A survey instrument was designed asking surgeons the number of implants performed and whether they had seen any cases of meningitis after implantation. If the answer was affirmative, they were asked to respond to a 20-point questionnaire. This instrument was sent to all 401 cochlear implant cen-ters in North America. Setting: Tertiary care referral centers. Patients: We studied all patients having received cochlear implants in North America. Main Outcome Measures: Number of cases of postimplant meningitis, age of patients, device used, cochlear and temporal bone abnormalities, treatment, and outcomes. Results: Meningitis is more common than previously thought. Risk factors included young age, cochlear dysplasia, temporal bone abnormalities, and the use of a two-part electrode system. This survey led to the involvement by the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention in a much more intensive analysis of a subset of the cases. Conclusions: Postimplant meningitis is related to patient, surgical, and device factors. By being aware of the risk factors involved, adhering to sound surgical principles such as packing of the cochleostomy with soft tissue, appropriately vaccinating patients, and eliminating any potentially traumatic electrode arrays, the incidence of meningitis should be significantly diminished.