Key pre-operative CT parameters for cochlear implantation: a focused radiologic review with surgical relevance

Abstract Purpose Cochlear implantation is an established treatment for severe to profound sensorineural hearing loss. Pre-operative computed tomography (CT) of the temporal bone is important for surgical planning, yet variability exists in how key imaging parameters are defined and measured across literature. This review highlights the key CT parameters with direct surgical relevance in cochlear implantation, evaluate current literature to address areas where radiological measurement remains ambiguous or inconsistently reported across studies, and to propose a practical framework to guide radiologists in preoperative CT evaluation for cochlear implantation. Methods A narrative review of the literature was performed on PubMed and EmBase in the period of 1 January 2000 to 1 March 2026 focusing on CT-based anatomical parameters relevant to the cochlear implantation with emphasis on its individual steps and relevant surgical impediments. Results The review identified key CT parameters relevant to cochlear implantation and proposed a structured neuroradiological framework for pre-operative assessment. This includes a stepwise assessment of the receiver–stimulator bed, mastoid, vascular variants, and posterior tympanotomy corridor, with planning for electrode insertion. Key thresholds identified include facial recess width <3 mm (predicting difficult access), tegmen height <3.5 mm (low-lying), and calvarial thickness <4 mm (risk of inner table breach). Standardised measurement of key parameters, including parasagittal facial recess width, and integration into a structured report were recommended. Conclusion Preoperative temporal bone CT provides essential anatomical information for cochlear implantation. Standardisation of parameter definitions and measurement techniques may enhance radiologic reporting, facilitate surgical planning, and reduce operative risk. A structured, surgically oriented CT assessment framework improves interdisciplinary communication.