Stapedectomy and variations of the facial nerve.

The aim of the study was to analyze the incidence of anatomical variations and abnormalities of the facial nerve found during stapedectomy. Specific management in the case of an anomalous course of the facial nerve was also described. A retrospective analysis of clinical records of 316 stapedectomies was carried out in search for facial nerve anomalies. In 25 (7.9%) patients the facial nerve had an abnormal course. Twenty patients exhibited partial and two total overhang of the nerve over the oval window. In two of them the facial nerve was dehiscent in the tympanic segment and in three patients an obliterative type of the disease was also noted. The facial nerve dehiscence without the protrusion was found in two more patients. Another individual demonstrated otosclerotic bone over the facial nerve. In one case a duplicated facial nerve was found. Two branches of the nerve were almost covering the oval window (Fig. 1B). The piston was placed in the footplate between the branches of the duplicated nerve. The patient developed slight facial weakness (grade III in H-B scale) after the surgery. The function of the facial nerve returned to normal within 5 months. Anomalies of the course of the facial nerve can be found in about 8% of stapedectomies and they require specific management. The knowledge of the possible abnormalities and relevant procedures is crucial for safe and successful stapedectomy.