Surgical planning for paediatric cochlear implantation in Warsaw Breakage Syndrome (WABS) using 3D reconstructed model of the malformed cochlea with a review of the literature

Warsaw Breakage Syndrome (WABS) is an ultra-rare autosomal recessive disorder, presenting with multiple abnormalities including sensorineural hearing loss due to cochlear malformation. Cochlear implant is a viable treatment for hearing loss in these patients. We report an implantation in a 2.91 year old girl with WABS who presented 1 year prior with bilateral severe sensorineural hearing loss. Radiological investigations revealed a bilateral Type-I Cochlear Hypoplasia). Using radiological images, we generated a 3D reconstruction of the labyrinth and auditory ossicles using the 3D Slicer image computing platform. The resulting models were 3D printed from a biocompatible resin and insertion of the cochlear implant electrode array was tested using a range of electrode models. Following this pre-surgical planning, an optimal electrode (Med-El Compressed) was selected based on size and positioning within the cochlea. The patient then underwent cochlear implantation and postoperatively has shown signs of hearing assessed through both electrophysiological and subjective approaches. The patient presented with severe bilateral cochlear malformation - hypoplasia of the basal turns, absent modiolus and cyst-like merging of the 2 nd and 3 rd turns. The preoperative 3D visualisation and printed model were instrumental in electrode array insertion, positioning, and selection of the ideal individual electrode. This consequently led to successful cochlear implantation (proper electrode placement, minimal complications, improved hearing thresholds and successful rehabilitation). Our findings, coupled with a review of similar rare cases in the literature, suggest that this approach could be broadly applicable to paediatric cases of cochlear hypoplasia with the future aim of optimizing postoperative outcomes.