Two-dimensional shape and dimensions of lower lateral alar cartilages (LLCs) for corrective rhinoplasty

Overview

Rebuilding a destroyed lower lateral cartilage is difficult partly because its natural shape has not been documented. The authors set out to record the dimensions and flattened outline of cadaveric tip cartilages. The intent is that a surgeon can cut that outline from a slice of rib cartilage and fold it into a three dimensional shape resembling the patient's original cartilage.

Sections of note

• Design: cadaveric anatomical study, 40 lower lateral cartilages from 20 fresh cadavers.
• Each cartilage was gently compressed front to back between microscope slides, photographed with a scale, and measured in ImageJ software.
• All two dimensional shapes were analyzed to find a common pattern.
• Cadaver age 38 to 77 years, mean 56.15. 17 male and 3 female. 95 percent Asian and 5 percent Caucasian.
• Templates were created and adjusted for size using the gathered measurements.
• The template shape was derived from the common pixel threshold at 25, which the authors state best resembled a native cartilage.
• The authors state this is the first study providing two dimensional shapes, dimensions and templates for these cartilages.

What it means for a patient

• Total tip cartilage reconstruction is needed when the original has been destroyed by previous surgery, injury or disease.
• Carving a flat shape and folding it is easier and more reproducible than carving a curved three dimensional structure freehand.
• The templates derive from cadavers with a mean age of 56 and a heavily male, heavily Asian sample, which may not represent all patients.
• This is a cadaver study. No patients were operated on, and no outcomes are reported.

Why this paper matters

Reconstructing a lost tip cartilage means recreating a shape most surgeons approximate from memory, and no published reference existed. Supplying measured templates converts that into a repeatable step. Whether templated reconstructions look or function better than freehand ones is untested.

Terms

• Lower lateral cartilage: the paired cartilages forming the nasal tip and nostril rims.
• Costal cartilage: cartilage from the ribs, harvested for use as a graft.
• Cadaveric study: research performed on donated human bodies.
• Anteroposterior: running from front to back.
• Pixel threshold: a setting determining which parts of an image count as the object being measured.
• Template: a pattern used to cut a shape reproducibly.