What types of iatrogenic facial nerve injuries (IFNIs) are most likely to occur in which circumstances?
Background: Some of the myriad causes of facial paralysis are potentially preventable, and IFNI is an attractive target for scrutiny. Reported rates of IFNI vary not only by procedure involved but also among studies addressing the same operation.
Explore this issue:January 2014
Study design: Retrospective chart review of all patients seen between 2002 and 2012.
Setting: Massachusetts Eye and Ear Infirmary, Boston.
Synopsis: A total of 1,810 patient records were reviewed; 102 patients were identified as having experienced IFNI. The majority of these patients had sustained segmental facial nerve injuries. The most common injury site was the facial nerve’s main trunk, followed by the upper division and the marginal mandibular branch; injuries were more common on the right side, and there were more than twice as many female patients with IFNI. The most common surgical procedure classes to result in IFNI were: 1) oral/maxillofacial surgery (40% of IFNI; included temporomandibular joint (TMJ) replacement operations and mandible fracture repair); 2) benign head and neck lesion resection (25% of IFNI; included parotidectomy and total hemifacial weakness); 3) otologic surgery (17% of IFNI; included mastoid surgery as a whole, specifically tympanomastoidectomy, cochlear implantation, mastoid obliteration, endolymphatic sac shunting, labyrinthectomy and glomus tumor resection), and 4) cosmetic surgery (11% of IFNI; included rhytidectomy). Limitations included the study’s retrospective nature and possible non-representation of patients with IFNI not referred to a facial nerve specialist, incomplete intraoperative data, and a possible selection bias.
Bottom line: Iatrogenic facial nerve injury occurs most commonly in TMJ replacement, mastoidectomy, and parotidectomy; surgeons must be intimately familiar with the facial nerve’s normal course and any anatomical variations to avoid injury.
Citation: Hohman MH, Bhama PK, Hadlock TA. Epidemiology of iatrogenic facial nerve injury: a decade of experience. Laryngoscope. 2014;124:260-265.