The Significance of Temporal Bone Computed Tomography in Postoperative Cochlear Implant Complications

Background: Delayed complications after cochlear implantation (CI) are not common but when they occur temporal bone computed tomography (CT) is considered to be a major investigation procedure.

Objective: The aim of this study was to examine the significance of CT in cases of postoperative CI-associated complaints.

Methods: A retrospective analysis of all CI patients who received a CT scan because of new CI-related complaints in a tertiary hospital between 2007 and 2016 was conducted.

Results: Seventy eight CI patients received a total of 89 temporal bone CT scans. The majority of the patients were over 18 years old (56.2%), 34.8% were between 5-18 years and 9% between 0-4 years old. In most cases CT was performed because of pain in the ear and implant region (33%), followed by poor CI performance (22%), trauma (13%) and subjective implant failure (10%). An inconspicuous CT was the most common finding (55%). Less common was the evidence of fluid in mastoid cells, with no clinical or radiological evidence of mastoiditis (23%). A dislocation or kink of the electrode was seen in 11% of the cases. Acute mastoiditis was diagnosed in 2%. No case of bone fracture was reported. In almost one third of the cases (28%) surgery was performed after the CT scan and in about half of these cases (15%) re-implantation was necessary. Remarkably 60% of these revision cases hat an inconspicuous CT scan.

Conclusion: CT scan is a useful examination in patients with delayed complications after CI, giving in some cases important information. However, data suggest that in many cases CT offers no further clue. Thus the indication should be assessed critically and be made individually.