Surgical Planning for Cochlear Implantation in Far-Advanced Otosclerosis: The Utility of OTOPLAN

Abstract

We read with interest the recent investigation by Bajin et al. (1) that reviewed the management and treatment outcome of far-advanced otosclerosis (FAO) patients. The authors concluded that co-chlear implantation (CI) represented a successful backup option in cases of stapedotomy failure, in accordance to current findings by other authors (2-4). Bajin et al. (1) performed CI in 13 of their FAO patients (65%), with full electrode insertion in all cases and no serious post-operative complications or side effects during follow-up. Unfortunately, the authors gave no information about the type and the length of the arrays used for surgery. The appropriate choice of CI array length represents a relevant subject, as incomplete electrode insertion remains one of the main problem in CI for FAO (3). Recently, we considered OTOPLAN (CAScina-tion AG; Bern, Switzerland) computer program in pre-operative decision for CI in FAO patients (4). OTOPLAN is a new software for pre-operative planning in otosurgery developed by CAS-cination (Bern, Switzerland) in cooperation with MED-EL (Innsbruck, Austria) (5). The software, using conventional computed tomography imaging , creates reconstructed images that give a more accurate view of cochlear lumen. Additionally, OTOPLAN calculates an estimated length for every cochlear turns and provides a report with a suggested array length to use in every patient (5). In our case series of FAO patients, we disclosed a mean OTOPLAN-estimated cochlear duct length of 32.4 mm (4). Furthermore, looking at OTOPLAN reconstructed imaging, we found fibrosis located in the cochlear lumen in the middle and apical turns in two FAO subjects (4). Considering all the findings from OTOPLAN software, we decided to change surgical plans and chose a shorter electrode (24 and 28 mm instead of 31 mm) to avoid incomplete insertion (4). This software preliminarily seemed useful for the appropriate array length choice in FAO patients and should be further investigated. Peer-review: Externally peer-reviewed.