Quantitative analysis of facial symmetry and animation following intraoral orthodromic temporalis transfer in facial paralysis.

This study aimed to quantitatively analyze the degree and vector of commissure excursion following intraoral orthodromic temporalis transfer. Patients with unilateral facial paralysis who underwent intraoral temporalis transfer were included. Intra-oral coronoidectomy was followed by submucosa tunneling through two vertical intraoral incisions to fixate the temporalis tendon to the perioral location. Oral commissure excursion, upper lip and commissure height differences, and smile angle were measured. Postoperatively, the symmetry of commissure excursion improved in repose (affected side: 114.6 ± 7.0 mm, non-affected side: 115.2 ± 4.9 mm, p = 0.134), while asymmetry arose in smiling (affected side: 30.7 ± 3.4 mm, non-affected side: 34.5 ± 4.4 mm, p = 0.001). Furthermore, the postoperative smile angle demonstrated insufficient vertical movement on the affected side during smiling (affected side: 115.6 ± 5.8°, non-affected side: 118.4 ± 4.9°, p = 0.002) but no significant difference in repose (p = 0.134). Within the limitations of the study it seems that intraoral orthodromic temporalis transfer yields excellent resting symmetry, but smile asymmetry may occur owing to insufficient oral commissure excursion. Nevertheless, as a minimally invasive surgery, this technique can obviate visible scars and benefit patients wishing for the same and can have excellent resting symmetry.