Author(s)
Vittorio V. Colletti
Giacomo G. Colletti, MD
Marco M. Mandalà, MD
Liliana L. Colletti, PhD
Affiliation(s)
International Center for Performing ABI in Children
Abstract:
Educational Objective: At the conclusion of this presentation, the participants should be able to identify and treat severe abnormalities of the rhomboid lip that make auditory brainstem implantation surgery in children with cochlear nerve deficiency a difficult and risky procedure. Objectives: To investigate the prevalence and implications of severe abnormalities of the rhomboid lip (RL) that make auditory brainstem implantation (ABI) surgery in children with cochlear nerve deficiency (CND) a difficult and risky procedure. Study Design: Retrospective study. Methods: In a cohort of 78 consecutive children with CND implanted with ABIs surgical video recordings and a full sequence of snapshots of the area surrounding the foramen of Luschka (FL) undergoing surgery were available for the present study. The individual surgical videos of each child were reviewed and analytically examined by four independent individuals to define the types and frequency of abnormalities of the RL. Results: The membranous structure forming the RL varied greatly in size, thickness and transparency in children of the present cohort. In a large number (72%) of children the RL extended laterally over the lower cranial nerves, obstructing the view of the FL and necessitating section of the RL to access the lateral recess (LR) and implant the ABI on the cochlear nuclei. Conclusions: An abnormal large RL adhering to the IX and X and obstructing the FL is described for the first time in children with CND during ABI surgery. A surgical dissection of the arachnoid membranes from the foramen jugularis down to cranial nerves VII, IX and X and delicate detachment of the RL from these nerves is necessary to visualize the FL, access the LR and locate the ABI array on the cochlear nuclei.