The Role of Subtotal Petrosectomy in Cochlear Implant Surgery-A Report of 32 Cases and Review on Indications

Objective: To report and review 32 cases of subtotal petrosectomy (SP) in cochlear implant (CI) surgery and to define the indications and contraindications for this procedure Study Design: Retrospective case review + case reports. Setting: Tertiary skull base center. Patients: Cochlear implant database: 32 subtotal petrosectomies in 31 patients. Interventions: Subtotal petrosectomy with blind sac closure of the external auditory canal, closure of Eustachian tube, and abdominal fat obliteration in combination with cochlear implantation. Results: Indications for SP in CI surgery were as follows: chronic otitis media (n = 4), previous radical cavity (n = 13), previous subtotal petrosectomy (n = 4), ossification of the cochlea (n = 5), malformation of the inner ear (n = 2), and temporal bone fracture (n = 4). One patient was simultaneously bilaterally implanted; 2 cases were revisions. All procedures were performed in 1 stage. In 2 cases, complications were encountered (6%), one of which lead to reoperation (3%). None of the patients was explanted. Conclusion: Subtotal petrosectomy combined with cochlear implantation is a procedure required in specific situations and lowers the risk of repetitive ear infections, CSF leakage, and meningitis by closing off all connection with the external environment. Additionally, it gives excellent visibility and access in difficult anatomy or in drill-out procedures. The complication rate of 6% is comparable with normal cochlear implantation. Preservation of residual hearing can be considered the only absolute contraindication as an open external meatus is necessary for use of electroacoustic stimulation. Risks of the SP+CI procedure are infection of the abdominal fat, breakdown of the blind sac closure, and entrapped cholesteatoma. Follow-up with CT imaging is therefore mandatory.