Air-collection behind the ear: a rare complication in cochlear implant surgery

A rare case of cochlear implant surgery complication is described: air collection behind the ear. A 61-year-old male with a 20-year history of progressive bilateral profound sensorineural hearing loss underwent cochlear implant surgery on the left ear with Clarion Hi-Res 90K (Advanced Bionics, Sylmar, CA, USA). Ten days after surgery, the patient presented visible tumefaction behind the ear corresponding to the receiver-stimulator. Ultrasonography, with a probe of 30 MHz, of the surface behind the ear showed formation of probable liquid content but aspiration with a 20-gauge needle yielded 30 cm3 of air without blood or pus. An unusual case is described of a minor complication occurring in an adult cochlear implant patient presenting a swelling behind the ear that was found to be collected air. Although ultrasonography can be useful to evaluate localization of swelling behind the ear and to differentiate between liquid and solid collection, it is not useful for identification of air collection. The Eustachian tube test can show an abnormally patent tube and prevent this complication.