Delayed-onset swelling around the implant after cochlear implantation: a series of 26 patients

Purpose We aimed to clarify the clinical features of delayed-onset swelling around cochlear implants (CI), and to present our experience on how to avoid and address this problem. Methods We performed a retrospective review of all CI cases at our institution between June 2001 and June 2020. Information on postoperative complications of swelling in the receiver area > 3 months after implantation were analyzed, and clinical data sheets were drawn. Results Twenty-six of 1425 patients (1.82%) with an age at implantation ranging from 1 to 9 years experienced delayed-onset swelling around the implant. Swelling episodes occurred as early as 4 months, and as late as 178 months after implantation (median, 79.7 months). The predisposing factor in 12 cases was unclear, 7 cases were caused by trauma at the implantation site, 5 cases were without predisposing factors, and 2 cases were related to infection. We found the frequency of delayed-onset swelling after cochlear implantation with different incision was statistically insignificant (P = 0.423). Nineteen patients (73.1%) were cured after one treatment, and five patients (19.2%) relapsed. Follow-up examinations at least 18 months after surgery revealed that all patients experienced a complete recovery. Conclusions Delayed-onset swelling at the receiver site is a long term but not exactly uncommon complication after cochlear surgery and long-term follow-up is eagerly required. It can recur more than once, causing more complex treatment strategies in clinical practice. Conservative treatment first recommended, while needle aspiration should initially be considered in recurrent cases also when the effusion swelling is > 3 ml.