Deossification of the Otic Bone in High Pressure CSF Otorhinorrhea: A New Radiological Finding.

To highlight a new radiological feature in a patient with labyrinthine malformation presenting with bilateral spontaneous high pressure cerebrospinal fluid (CSF) otorhinorrhea. Study design-retrospective case review. Setting-academic, tertiary cochlear implant center. A cochlear implantee with Incomplete Partition Defect (Type 1) presented with meningitis and CSF otorhinorrhea for which she initially underwent medical treatment. High resolution computed tomography (HRCT) of the temporal bone with CT cisternography was performed for identifying the site of the CSF leak. HRCT and CT cisternography revealed a defect in the region of the stapes foot plate and marked thinning/deossification of the cochlear promontory. These two findings were absent in the pre-implant imaging of the patient done 3 years ago. Surgery by endaural approach was undertaken to close the site of CSF leak. Intraoperatively, marked thinning of the cochlear promontory was observed, corresponding to 'blue lining' of the labyrinth in otologic surgery. This intraoperative finding indicating high intralabyrinthine CSF pressure correlated well with the imaging findings. Primary surgical repair resulted in successful CSF leak closure followed by theco-peritoneal shunting to prevent recurrence of the leak. The patient is using her cochlear implant and doing well with auditory verbal therapy. She is asymptomatic till date. Thinning and deossification of the otic capsule on HRCT is an important indicator of high CSF pressure in patients with labyrinthine malformations. Our case study highlights the need for heightened radiological and clinical vigilance in this subgroup of patients to predict complications and ensure prompt intervention. © Association of Otolaryngologists of India 2020.