Facial Nerve Dehiscence at Mastoidectomy for Cholesteatoma

Objective: The incidence and localization of facial nerve dehiscence (FND) in patients undergoing mastoidectomy for middle ear cholesteatoma were determined. Various clinical factors predictive of FND preoperatively were also researched. Materials and Methods: A retrospective review of 112 patients (115 ears) undergoing mastoidectomy by canal wall-up or canal wall-down methods during a five-year period was conducted, recording occurrence rates and sites of FND at the time of surgery. Correlations between FND and clinical features (age, sex and surgical technique) or intraoperative findings (dural exposure, labyrinthine fistula, and the absence of the stapedial suprastructure) were ascertained, based on Fisherʼs Exact or Chi-Square statistical analyses. Results: FND occurred in 33 (28.7%) of 115 ears. Involvement of tympanic segment only (81.8%) predominated over mastoid segment alone (9.1%) or tympanic and mastoid segments together (9.1%). Intraoperative absence of stapedial suprastructure was significantly with FND (p=0.012), while dural exposure or labyrinthine fistula at surgery and FND showed no clear associations (p>0.05). Conclusion: The incidence of FND was 28.7%, with preferential involvement of tympanic segment. Since the absence of stapedial suprastructure correlated with FND, lost integrity of the stapes may preoperatively predict FND. Therefore, otologic surgeons should be particularly cautious during mastoidectomy, given these conditions.