Anatomical Study of the Medial Crura and Its Effect On Nasal Tip Projection

INTRODUCTION AND AIMS: Open rhinoplasty techniques are commonly used to address nasal tip support and projection. Although, a variety of techniques have been described, the decision making in the application of these techniques remains unclear. Our observation is that changes in nasal tip projection depend on the morphology and strength of the medial crus. The aims of our study are firstly, to study the morphology and variation in medial crura and secondly, quantify the changes in tip projection after surgical intervention.

METHODS: Ten cadaver heads were dissected with an open rhinoplasty approach. Two observers obtained four anthropometric measurements: columellar length (sn-c), columellar width (c-c), nasal tip projection (sn-prn) and nasal bridge length (n-prn). The shape of the medial crus was noted. Anthropometric measurements were made prior to any intervention and after each of the following procedures: (1) elevation of skin envelope and closure of the columellar incision, (2) interdomal and transcolumellar sutures, (3) placement and fixation of a columellar strut.

RESULTS: There were 8 male cadavers with an age range of 60-75 years. Three anatomical variations of the medial crura were noted: weak, buckled (type 1, n=7), strong, flared outward (type 2, n=1) and strong, straight (type 3, n=2). Elevation of the skin envelope and closure resulted in reduction in projection in type 1 noses (-3mm) compared to type 3 noses, which remained the same. Suturing techniques and columellar strut insertion resulted in increased range of projection in type 1 noses (+2-5mm) compared to type 3 noses, where there was a marginal increase (0-2mm). Insertion of a columellar strut in type 3 noses increased the columellar width by 1-2 mm.

CONCLUSION: Changes in columellar length and tip protrusion are dependent on the shape and strength of the medial crura.  Observation of the medial crus anatomy during an open rhinoplasty allows the surgeon to anticipate and plan the resulting outcome in both reconstructive and aesthetic rhinoplasty.