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Original Investigation
September 5, 2019

Assessing Nasal Soft-Tissue Envelope Thickness for Rhinoplasty: Normative Data and a Predictive Algorithm

Author Affiliations
  • 1Department of Otolaryngology–Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota
  • 2Department of Radiology, Mayo Clinic, Rochester, Minnesota
  • 3Division of Facial Plastic and Reconstructive Surgery, Mayo Clinic, Rochester, Minnesota
JAMA Facial Plast Surg. Published online September 5, 2019. doi:10.1001/jamafacial.2019.0715
Key Points

Question  How does nasal soft-tissue envelope (STE) thickness vary in our patient population, and can facial plastic surgery clinicians predict nasal STE thickness based on visual examination of the nose?

Findings  This study of 190 patients found that the STE is thickest at the sellion, thinnest at the rhinion, thickened over the supratip and nasal tip, and thinned over the columella; thickness followed a near-normal distribution for each measured subsite, with the majority of patients in a medium thickness range. The 4 study experts accurately predicted nasal STE thickness from clinical photographs, with the highest accuracy at the nasal tip.

Meaning  Experts can accurately predict nasal STE thickness based on visual examination of the nose, which has implications for surgical planning in rhinoplasty.

Abstract

Importance  Preoperative assessment of nasal soft-tissue envelope (STE) thickness is an important component of rhinoplasty that presently lacks validated tools.

Objective  To measure and assess the distribution of nasal STE thickness in a large patient population and to determine if facial plastic surgery clinicians can predict nasal STE thickness based on visual examination of the nose.

Design, Setting, and Participants  This retrospective review and prospective assessment of 190 adult patients by 4 expert raters was conducted at an academic tertiary referral center. The patients had high-resolution maxillofacial computed tomography (CT) scans and standardized facial photographs on file and did not have a history of nasal fracture, septal perforation, rhinoplasty, or other surgery or medical conditions altering nasal form. Data were analyzed in March 2019.

Main Outcomes and Measures  Measure nasal STE thickness at defined anatomic subsites using high-resolution CT scans. Measure expert-predicted nasal STE thickness based on visual examination of the nose using a scale from 0 (thinnest) to 100 (thickest).

Results  Of the 190 patients, 78 were women and the mean (SD) age was 45 (17) years. The nasal STE was thickest at the sellion (mean [SD]) (6.7 [1.7] mm), thinnest at the rhinion (2.1 [0.7] mm), thickened over the supratip (4.8 [1.0] mm) and nasal tip (3.1 [0.6] mm), and thinned over the columella (2.6 [0.4] mm). In the study population, nasal STE thickness followed a nearly normal distribution for each measured subsite, with the majority of patients in a medium thickness range. Comparison of predicted and actual nasal STE thickness showed that experts could accurately predict nasal STE thickness, with the highest accuracy at the nasal tip (r, 0.73; prediction accuracy, 91%); . A strong positive correlation was noted among the experts’ STE estimates (r, 0.83-0.89), suggesting a high level of agreement between individual raters.

Conclusions and Relevance  There is variable thickness of the nasal STE, which influences the external nasal contour and rhinoplasty outcomes. With visual analysis of the nose, experts can agree on and predict nasal STE thickness, with the highest accuracy at the nasal tip. These data can aid in preoperative planning for rhinoplasty, allowing implementation of preoperative, intraoperative, and postoperative strategies to optimize the nasal STE, which may ultimately improve patient outcomes and satisfaction.

Level of Evidence  N/A.

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