Learning Objectives: Patient's history should always be listened carefully. The otologic surgeon should always be prepared for the unexpected. We should always listen carefully to the patient's history. The otologic surgeon should always be prepared for the unexpected.
Introduction: Anatomical anomalies of the facial nerve range from common minor bony dehiscence of the tympanic segment to much rarer abnormalities in the course of the nerve. Normally their only relevance is that they may pose an increased risk of injury during tympanomastoid surgery.
Method: We report the case of a 60 year old female who presented to the general ENT clinic with right-sided conductive hearing loss. Eventually a grommet was inserted under LA. The hearing did not improve. She was referred to the senior author for tympanotomy. On the day of surgery the patient was asked again about the history of her symptoms and she admitted that she could not be sure if the hearing in her right ear had ever been normal. A permeatal tympanotomy was performed under GA. The ossicular chain was found to be intact and mobile. However, the appearance of the promontory was noted to be unusual. The facial nerve was seen to be dehiscent and passing both above and below the stapes(intra-operative photograph). This was confirmed by the use of the nerve stimulator. The operation was abandoned and the patient was subsequently informed of the findings.
Result: Post-operative recovery was uncomplicated. Post-operative audiometry showed no change in hearing. Preoperative imaging had not been requested as the diagnosis had not been suspected. However, review of the patient's records showed that the patient has had a previous CT scan of the sinuses. On close review of these images, an anomalous course of the facial nerve could be seen(CT images).
Conclusion: A facial nerve bifurcating and encircling the stapes is extremely rare and would never have been suspected as the cause of conductive hearing loss. Very few reports of such an anomaly appear in the literature.
