Etiology and therapy of delayed facial paralysis after middle ear surgery.

Purpose: This review focuses on the etiology, incidence and therapy of delayed paralysis of the facial nerve (DFP) after different types of middle ear surgery.
Methods: Retrospective review of studies published in English from 1970 until 2019 reporting DFP after tympanoplasty, tympanomastoid surgery, stapedotomy and stapedectomy. The search used the databases of PubMed, Scopus and Cochrane Library. Studies reporting from adult patients and DFP onset after 48 h after surgery were included. Studies dealing with iatrogenic or preexisting facial palsy and case reports were excluded. The initial literature search resulted in 52 studies. The relevance of the publications was verified using title, abstract and full-text analysis. Data were analyzed with descriptive statistics using median, simple sum and statistical significance.
Results: Ten studies having 12,161 patients could be included in this review. The incidence of DFP after the middle ear surgeries varies between 0.2 and 1.9%. The surgical stress of the middle ear surgeries is the main trigger for the development of DFP and leads to a virus reactivation and/or neuronal edema. Patients with a dehiscence of the facial canal have a significantly higher probability for a DFP. The recommended therapy of DFP based on the data of the therapy of Bell's palsy, consists of the administration of a steroid. For patients having a case history of previous viral infections, an antiviral prophylaxis is recommended.
Conclusion: Overall, DFP has a very good prognosis, with mostly complete healing with appropriate therapy. Viral reactivation is the most favored genesis of DFP. Immunization or antiviral prophylaxis is recommended to those patients being at risk for a viral reactivation.