Effect of size difference between hemiglossectomy and reconstruction flap on oral functions: A retrospective cohort study.

Abstract

Forearm free flaps are used after hemiglossectomy. However, no investigation has been performed on whether oral functions are better preserved when sizes of the resection and reconstruction flap are exact matches, or whether the size of the resection should be changed. We aimed to retrospectively examine whether size differences between the resection and reconstruction flap affect speech and swallowing functions postoperatively, and to determine whether there are more favorable flap size ratios. This is a retrospective cohort study of patients undergoing hemiglossectomy using a forearm free flap between 2006 and 2016 at Kobe University Hospital, Japan. The effect of size difference between the resection and reconstruction flap on maintained oral function was assessed. Speech and swallowing functions were assessed, and their correlation with the ratio of the flap size to that of the resected area was determined. With these data, distribution maps of the relationship between the functional level and reconstructed dimension ratio were prepared. The more suitable reconstructed dimension ratio was examined and evaluated. The Fisher exact test, Kruskal-Wallis test, and Scheffe test were used in statistical analyses. Eighty-eight patients underwent hemiglossectomy using a forearm free flap during a 10-year period. Of these cases, 66 patients were included in this study, while 22 were excluded. The ratio of the area of the reconstruction flap to that of the resection site was 0.59-2.79 (median: 1.61). Sixty patients had flaps greater than the resection area, whereas 6 had smaller flaps. Significant differences were found in speech intelligibility and swallowing function when the reconstructed dimension ratio was categorized as follows: ≤1.3, 1.3-1.8, and ≥1.8. Our findings suggest that postoperative deterioration of oral functions after hemiglossectomy could be reduced if reconstruction is performed using a forearm free flap with a surface area 1.3 to 1.8 times greater than that of the resection area.