Smile analysis in rhinoplasty: a randomized study for comparing resection and transposition of the depressor septi nasi muscle.

[BACKGROUND] The depressor septi nasi muscle is responsible for smiling deformity. Its manipulation is beneficial in patients with muscle hypertrophy. In addition, it enhances the smile and tip-lip relationship. In this study, depressor septi nasi muscle excision through a transfixion incision is compared with its transposition through an upper labial sulcus incision.

[METHODS] Two techniques of depressor septi nasi muscle treatment were performed randomly for rhinoplasty cases. Smile analysis in rhinoplasty, consisting of measurements of nasal length, nasal diagonal, tip projection, and upper lip height, and noting transverse upper labial crease in repose and full smile, was performed on preoperative and postoperative photographs.

[RESULTS] One hundred patients were studied in two equal groups. Preoperatively, tip projection and upper lip height were decreased significantly with smiling. Generally, the effect of smiling on all five parameters was decreased significantly following rhinoplasty. The two different techniques were not significantly different in decreasing the effects of smiling on nasal length, nasal diagonal, tip projection, upper lip height, or transverse crease.

[CONCLUSIONS] The two different techniques were the same in decreasing the effects of smiling. The authors recommend smile analysis in rhinoplasty, consisting of measurement of nasal length, nasal diagonal, tip projection, and upper lip height, and noting transverse upper labial crease in repose and during smiling, before rhinoplasty for preoperative evaluation and after the operation for outcome assessment. Depressor septi nasi muscle treatment should be considered if a decrease in tip projection or upper lip height with smiling or a transverse upper labial crease during smiling is extraordinary or unsightly.

[CLINICAL QUESTION/LEVEL OF EVIDENCE] Therapeutic, II.