CSF gusher in cochlear implantation: The risk of missing CT evidence of a cochlear base defect in the presence of otherwise normal cochlear anatomy

Abstract

Intraoperative cerebrospinal fluid (CSF) leakages from the cochleostomy site - known as gushers - are a serious complication of cochlear implantation surgery in cases of congenital deafness. They occur as the result of abnormal communication between CSF in the internal auditory canal and perilymph in the cochlea. Gushers are well recognized as occurring in a proportion of cases in which there is a clearly visible congenital malformation of the cochlea. In this report, we describe two cases in which pre-operative computed tomography (CT) scanning of the cochlea was initially reported as normal but gushers occurred during cochlear implant surgery. In both cases, more detailed review of the CT scans (peroperatively in the first case, pre-operatively in the second case) showed a defect at the cochlear base, in the absence of any other cochlear malformation. The aim of this paper is to draw attention to the risk of missing this abnormality and to encourage careful inspection of the cochlear base on CT scans in all cases, even when the rest of the cochlear appears normal.

CSF Gusher in Cochlear Implant Surgery–does it affect surgical outcomes?

“…Luntz et al (1997) attributed CSF leak with normal CT scans in two patients to membranous anomalies [23]. Cabbarzade (2015) found bony defect in the basal part of cochlea in CT scans of two patients with intraoperative CSF leak previously reported normal [24]. In our series, four patients had normally reported CT and MRI scans of temporal bone.…”

Meningocele of the Internal Auditory Canal Requiring Facial-Nerve Decompression

“…The lack of bone covering between the cochlea and the IAC also raised concerns for pursuing surgical intervention, as communication between the perilymph in the cochlea and the IAC raises concerns of a CSF gusher [3]. CSF gushers may be difficult to control intraoperatively and may lead to postoperative meningitis.…”

Incidencia y manejo del gusher en la implantación coclear

“…Es importante destacar la relación existente entre la presencia de gusher y las malformaciones del oído interno, debido a que estas se presentan de manera visible en el estudio de imagen prequirúrgico hasta en un 20% de los pacientes con hipoacusia sensorineural de grave a profunda. Destaca la presencia de acueducto vestibular ensanchado como la anomalía más frecuente, y presenta una relación ampliamente conocida con la ocurrencia de gusher durante la implantación coclear 4 . La incidencia de gusher en nuestro trabajo fue del 4.2% (12/276), porcentaje que concuerda con lo reportado en la literatura sobre el tema.…”

“…-Grave: además de las medidas mencionadas, se realizaron empaquetamiento del oído medio y obliteración de la trompa de Eustaquio para detener la fuga. Así mismo, tres otorrinolaringólogos y un radiólogo entrenados en el campo de otología hicieron una revisión retrospectiva de los estudios de imagen prequirúrgicos que involucró la medición de diversas estructuras del oído interno mediante software especializado, y clasificaron las diversas malformaciones del oído interno que encontraron según la clasificación de Sennaroglu 4 .…”