Varied Definitions of Nasolabial Angle: Searching for Consensus Among Rhinoplasty Surgeons and an Algorithm for Selecting the Ideal Method

Abstract

Background:The nasolabial angle (NLA) is an important aesthetic metric for nasal assessment and correction. Although the literature offers many definitions, none has garnered universal acceptance.Methods:To gauge the consensus level among practitioners, surveys were administered to a convenience sample of rhinoplasty surgeons soliciting practice characteristics, self-assessment of rhinoplasty experience and expertise, and preferred NLA definition. Choices of NLA definition included the angle between: (A) columella and line intersecting subnasale and labrale superius; (B) columella and line tangent to philtrum; (C) nostril long axis and Frankfort perpendicular; and (D) nostril long axis and vertical facial plane.Results:Of the 82 total respondents, mean age was 50 years (range, 30–80years), and mean professional experience was 17 years (range, 0–67 years). Nineteen described themselves as novice rhinoplasty surgeons, 27 as intermediates, and 36 as experts. Mean number of lifetime rhinoplasties performed was 966 (range, 0–10,000). Twenty respondents (24%) agreed with definition A, 27 (33%) with B, 16 (20%) with C, and 13 (16%) with D. Six chose “other,” offering their own explanations of NLA. Self-identified novices were more likely to prefer definition D than were experts (P = 0.009).Conclusions:No majority consensus was reached regarding the definition of NLA. Each method has its benefits and drawbacks, and establishing a single one may be unnecessary and even counterproductive in some cases. Having options available means that surgeons can tailor to each encounter, as long as they adopt a systematic methodology. We submit an algorithm to facilitate this effort.

Association between Lateral Cephalometric Changes in X-Y Coordinate System and Profile Changes among Skeletal Class III Patients after Orthognathic Surgery

“…6 Maxillary, Functional Occlusal and Mandibular plane angles to Sn line ( Figure 4 ) and NLA angle ( Figure 5 ) were considered as angular variables. 7 …”

“…6 Maxillary, Functional Occlusal and Mandibular plane angles to Sn line (Figure 4) and NLA angle (Figure 5) were considered as angular variables. 7 All of the coordinate, linear and angular variables in the form of T2-T1 were finally statistically analyzed. Furthermore, to obtain the range of subsequent orthogonal change points on the X-Y coordinate plane, as in the envelope of discrepancy, the two-dimensional point change range was displayed as a diagram (envelope of change).…”

Assessment of Cranial Sexual Dimorphism Using 3D Reconstruction: Implications for Gender-Affirming Surgery

“…1E). 10 The nasofrontal angle was measured as the angle intersecting at the nasion, with lines extending to the glabella and nasal dorsum (Fig. 1F).…”

Changes in nasolabial angle may alter nasal valve morphology and airflow: a computational fluid dynamics study

“…The nasolabial angle (NLA) is the angle between the base of the nose and the upper lip. This angle should be between 100-110 degrees for women and 90-105 degrees for men (Figure 1B) (7,8). Changes in the NLA may cause changes in the angles and distances of the INV and ENV planes relative to each other and can change the morphology and volume of the NVR (9).…”