Impact of primary cochlear implantation packing materials on reimplantation surgical difficulty and histopathological outcomes: a retrospective cohort study

Background: Cochlear implantation (CI) is the first choice for the treatment of severe to profound sensorineural hearing loss. This study evaluated the impact of primary CI packing materials on intraoperative findings and surgical outcomes in subsequent reimplantation. To identify strategies that minimize adverse tissue reactions, reduce reimplantation difficulty, and maximize success rates. In a retrospective cohort study of 77 cochlear reimplantations, patients were stratified into packing or non-packing groups based on material presence at reimplantation. Baseline characteristics, intraoperative findings, and prognostic outcomes were analyzed and compared. Statistically significant differences were observed between the packing and non-packing groups regarding the presence of fibrous adhesion within the mastoid cavity ( p = 0.016), facial recess bone hyperplasia ( p < 0.001), granulation tissue formation ( p < 0.001), cochlear ossification ( p < 0.001), and the need for cochleostomy re-expansion ( p = 0.001). The mean Categories of Auditory Performance score was lower in the packing group (4.75) compared to the non-packing group (5.16); however, this difference was not statistically significant ( p = 0.192). Residual packing materials from primary CI increase intraoperative complexity during revision surgery, potentially compromising procedural success. Minimizing non-essential packing material use during initial implantation is strongly recommended to facilitate future revisions.