Delayed Facial Nerve Weakness After Intact Canal Wall Tympanomastoidectomy

Objective: To find the etiology, frequency, and prognosis of delayed facial nerve weakness (DFW) in our department after intact canal wall tympanomastoidectomy for a tubotympanic (TT) type of chronic suppurative otitis media (CSOM) without cholesteatoma. Study Design: Retrospective case review. Setting: Tertiary care center. Subjects and Methods: A total of 315 patients who underwent intact canal wall tympanomastoidectomy for TT type of CSOM without cholesteatoma in our department for the past 3 years were selected. Patients with facial nerve weakness after 72 hours of surgery were noted and assessed for a history of herpes zoster virus infection. There were 6 patients who developed DFW; of these, blood samples of 4 patients for serum antibody titers to varicella zoster virus and herpes simplex type 1 were sent on the 3rd day of developing DFW. Blood samples of each of the remaining 2 patients were sent on the 13th day and 1st day of developing DFW. All 6 patients were treated with prednisolone and acyclovir, and their prognosis was assessed. Main Outcome Measure: House-Brackmann facial nerve grading system and serum antibody titers for varicella zoster virus and herpes simplex type 1. Results: Six patients (1.9%) developed DFW in this study. All patients had a history of herpes zoster virus infection. Serology results of 4 patients showed positive immunoglobulins M and G for varicella zoster virus and had significantly elevated titers of serum immunoglobulin G for varicella zoster virus, thus confirming the etiology. Conclusion: The incidence of DFW after tympanomastoidectomy is low and is due to viral reactivation, that is, varicella zoster. The overall prognosis seems impressive because all of the patients' facial nerve function improved by the end of 6 weeks. This study also illustrates the medicolegal importance of informing the patients with a history of herpes zoster virus infection the chance of developing DFW after undergoing tympanomastoidectomy.