Facial nerve reconstruction following parotidectomy for malignancy: A systematic review of microsurgical techniques and functional outcomes.

Abstract

Radical parotidectomy with facial nerve sacrifice results in complete ipsilateral facial paralysis. Although immediate microsurgical reconstruction is the standard of care, no comparative trials have been conducted, and technique selection remains empirical. A PRISMA 2020-compliant systematic review (PROSPERO: CRD42025643307) was conducted. Scopus, Web of Science, and PubMed/MEDLINE were searched from inception to June 2025. Two reviewers independently screened studies and extracted data. Risk of bias was assessed using the Newcastle-Ottawa Scale and MINORS. Certainty of evidence was evaluated using GRADE. Eighteen studies enroling 312 patients across ten countries (2000-2021) were included. Six technique subgroups were identified: non-vascularised cable graft (n=155), mixed-donor graft (n=38), vascularised thoracodorsal nerve free flap (n=46), masseteric nerve transfer (n=27), venous conduit (n=3) and combination approaches (n=43). House-Brackmann Grade I-III was achieved in 44% of patients across ten standard-grading studies (range, 24-100%). Postoperative radiotherapy did not impair graft function in four comparative studies. Masseteric nerve transfer yielded earlier reinnervation (4-6 months) than cable grafting (6-13 months). Risk of bias was moderate (NOS 6-9/9; MINORS 8-11/16). Overall certainty of evidence was Very Low (GRADE). Immediate facial nerve reconstruction provides meaningful functional recovery regardless of technique, and postoperative radiotherapy does not impair graft function. Masseteric nerve transfer offers earlier reinnervation; vascularised nerve-free flaps may be preferred for large defects or long neural gaps. A decision-making framework is proposed; prospective comparative trials with standardised outcome reporting are required.