Predictive Evaluation of Septal Cartilage-bone Complex for Rhinoplasty Using Cone Beam Computed Tomography

Overview

Septal extension grafting lengthens short noses, and when septal cartilage is insufficient the adjacent septal bone can be included. The authors assessed outcomes with a combined cartilage and bone complex, and tested whether cone beam CT taken before surgery could predict usable bone, using Hounsfield units, a measure of tissue density.

Sections of note

• Design: retrospective review of Korean women planned for septal extension grafting, July 2021 to June 2022. Scans measured Hounsfield unit values for septal cartilage, the ethmoid plate and the vomer.
• 19 of 27 patients had the combined graft; 8 did not because the bone was unsuitable.
• In the 19 who proceeded, average ethmoid density was 286.5 units, ratio 6.8, and vomer 230.3 units, ratio 5.7.
• The grafting significantly improved nasal length and tip projection, though tip softness was less favorable.
• Of the 8 excluded, 5 had bone too thick and stiff, ethmoid density 667.8, ratio 15.5; the other 3 had fragile bone, ethmoid density 148.7, ratio 3.1.

What it means for a patient

• Septal bone quality varies enough that roughly 3 in 10 patients here could not use it, in both directions: too hard to shape or too brittle to hold.
• A scan before surgery can predict which group a patient falls into, avoiding a plan that fails in the operating room.
• Tip softness was worse with the combined graft, which is the trade off for a stiffer support.
• Limits: 27 patients, all women from one population, retrospective, no comparison group, no stated follow up.

Why this paper matters

Running out of septal cartilage forces a choice between rib, ear or donor material, each with its own cost, and adjacent septal bone avoids all three when suitable. Turning that judgment into a preoperative measurement is the contribution. The density thresholds come from 27 patients and need confirming in larger groups.

Terms

• Septal extension graft: cartilage fixed to the septum that carries the tip in a set position.
• Cone beam computed tomography: a lower dose CT variant small enough for an office setting.
• Hounsfield unit: a scale measuring tissue density on a CT scan.
• Perpendicular plate of the ethmoid: the thin bone forming the upper rear part of the septum.
• Vomer: the flat bone forming the lower rear part of the septum.