A systematic review on the sensory reinnervation of free flaps for tongue reconstruction: Does improved sensibility imply functional benefits?

BACKGROUND: Tongue reconstruction after (hemi)glossectomy including sensory recovery is challenging. Although sensory recovery could improve functional outcome, no consensus on the need for reinnervation of the neo-tongue exists. Therefore, a systematic review was performed to determine if sensory reinnervation of free flaps in tongue reconstruction is better than no sensory reinnervation. The secondary study aim was to assess the effect of sensory reinnervation on overall functional outcome, such as speech and deglutition. METHODS: Seven databases (Embase, Medline, Web of Science, Scopus, PubMed publisher, Cochrane, and Google Scholar) were searched. Studies that reported the effect of sensory reinnervation on overall functional outcome were identified. RESULTS: Fourteen articles were included in the systematic review, concerning a total of 271 tongue reconstructions. Free flaps that were used were the radial forearm (RF) flap (n = 137), the anterolateral thigh (ALT) flap (n = 65), the rectus abdominis (RA) flap (n = 20), and the tensor fascia latae (TFL) flap (n = 5). Seven out of seven articles directly comparing sensory reinnervation with no sensory reinnervation revealed superior sensibility in the reinnervated group. Moreover, the innervated RF and ALT flaps showed superior recovery of sensibility compared to other flaps used for the reconstruction of hemiglossectomy as well as total glossectomy defects. There are indications that sensory reinnervation may have a beneficial effect on overall tongue function. Age, smoking, and sex did not affect sensory recovery. Four out of five articles showed that postoperative radiotherapy does not have a long-term adverse effect on sensory recovery. CONCLUSIONS: Sensory reinnervation of free flaps in the reconstruction of (hemi)glossectomy defects improves sensory recovery; however, evidence for beneficial effects on function is poor.