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

Kalantar-Hormozi A, Beiraghi-Toosi A.

What this paper says

In 100 rhinoplasty patients randomly assigned to two ways of treating the depressor septi nasi muscle, both methods reduced the pulling effect of smiling on the nose by the same amount.

Overview

The depressor septi nasi muscle pulls the tip down and shortens the upper lip during a smile. This randomised study compared cutting the muscle out through a transfixion incision against moving it through an incision in the upper lip sulcus. Photographs before and after surgery were measured at rest and during a full smile.

Sections of note

Randomised comparison of two techniques during rhinoplasty, with 100 patients in two equal groups.
Measurements were nasal length, nasal diagonal, tip projection and upper lip height, plus presence of a transverse upper labial crease.
Photographs were taken in repose and in full smile, before and after surgery.
Before surgery, tip projection and upper lip height fell significantly when patients smiled.
After rhinoplasty, the effect of smiling on all five parameters was significantly reduced.
The two techniques did not differ significantly on any of the five parameters.
The paper is graded therapeutic level of evidence II.

What it means for a patient

If the nose drops or the lip shortens when you smile, surgery on this small muscle can reduce that movement.
Neither surgical route was better than the other here, so the choice can rest on other factors.
The abstract gives no follow-up length and no patient satisfaction scores, so durability and how patients rated the change are unknown.

Why this paper matters

Most rhinoplasty assessment uses a still face, and this study argues for measuring the nose during a smile as well. It leaves open how long the effect lasts and whether patients notice the difference in daily life.

Terms

Depressor septi nasi: a small muscle that pulls the nasal tip downward when you smile.
Transfixion incision: a cut made through the columella inside the nose.
Upper labial sulcus: the groove where the upper lip meets the gum.
Tip projection: how far the tip stands out from the face.
Transverse upper labial crease: a horizontal fold across the upper lip during smiling.

Summary written by rhinoplasty.cc from the abstract, 2026-09-08; not medical advice. The authors' own abstract follows.

From the abstract

“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…”

Excerpt; the full abstract is on PubMed.