Cochlea Implantation in inner ear malformations: Complications and Reimplantation-rate

Introduction Congenitalsensorineural hearing loss in case of malformations of the bony labyrinth can today be sucessfully rehabilitated with cochlea implantation, however the operation could challenging due to CSF leak, electrode dislocation and electrode choice. The security profile of the operation and its rehabilitation results remain underinvestigated.

Materials und Methods 111 Patients with inner ear malformation were identified and anatomically classified between 1997 and 2022. The concurring syndroms, the intraoperative findings and the postoperative surgical and rehabilitation results were analyzed.

Results 137 dysplastic cochleas were implanted. The most frequent malformations were incomplete partition type II (57), Type I (45), cochlea aperture stenosis (26) and cochlea hypoplasia type III (20). The most common intraoperative complication was perlymph gusher in incomplete partitions. Electrode dislocation in the inner ear canal were detected in five cases in cochlea hypoplasia and incomplete partition Type I and III. Long term complications such as meningitis or otoliquorrhea were not registered. In 22 cases a reimplantation was necessary. The hearing results were dependant on the modiolus development, however the presence and functionality of the cochlear nerve remained the most important prognostic factor for audiological rehabilitation.

Conclusions With the proper classifaction and consequent surgical planning cochlea implantation in case of inner ear malformations is a challenging but secure procedure. The most common complication remains perilymph gusher. The condition of the cochlear nerve is the most important factor for a successful rehabilitation indipendent of cochlea anatomy.

Publication History

Article published online:
19 April 2024