To compare the clinical effect of the Yu flap and the Karapandzic flap in repairing greater than 2/3 defects of the lower lip and to provide a reference for clinical application.

Ten patients with greater than 2/3 lower lip defects after surgical resection of lower lip tumors and vascular malformations were enrolled: 5 patients were repaired with the Yu flap (Yu flap group) and 5 patients were repaired with the Karapandzic flap (Karapandzic flap group). Follow-up for at least 1 year was conducted to evaluate the morphology (symmetry, stoma, exposure of vermilion) and function (sensory function, motor function) of the reconstructed lower lip.

All the flaps survived, and all wounds showed primary healing. The lower lips reconstructed with the Yu flap or the Karapandzic flap obtained similar satisfactory oral function. The sensory function was essentially restored. There were no obvious obstacles in speech and expression, and no saliva leakage occurred. In the Yu flap group, only 1 patient had slight microstomia. In the Karapandzic flap group, 2 patients had slight microstomia and 3 patients had moderate microstomia. 90% (9/10) of the patients were very satisfied with the postoperative outcome, and 1 patient in the Karapandzic flap group was basically satisfied.

Ten patients with greater than 2/3 lower lip defects and reliable outcomes can be achieved. These two methods can achieve similar oral functions, but the effect of the Karapandzic flap is inferior to that of the Yu flap in terms of aesthetic appearance, and microstomia often occurs, while the Yu flap can generally maintain the original size of the mouth cleft.