Depth and Lumen Diameter of the Superior Labial Artery with a Clinical Application to Dermal Filler Injection
Authors: Money Silas , Wall Weston , Davis Loretta , Edmondson Anna 
Published: June 2021

Introduction

Since 2000, the annual administration of dermal filler treatments has risen by over 250 percent, stemming from their minimally invasive and relatively inexpensive nature compared to traditional cosmetic surgery. Currently, numerous levels of healthcare practitioners administer over 160 temporary and permanent filler treatments for correcting age‐related wrinkles/folds and non‐age‐related tissue volume defects from surgery or trauma. Unfortunately, the variance in clinician level of training combined with the use of unapproved products has increased the incidence of dermal filler complications in recent years. While common complications such as bruising, erythema, and edema are relatively mild and temporary, the rarer complication of vascular occlusion and subsequent tissue necrosis is disfiguring and difficult to reverse. Lip and nasolabial fold injections—which involve regions supplied by the superior labial artery—are the most likely to result in tissue necrosis.

Purpose

The purpose of this study was to examine anatomic features of the superior labial artery (SLA) relevant to dermal filler injection in the clinical setting.

Materials & Methods

Eighteen adult embalmed cadavers (36 hemi‐faces; 9 males, 9 females; ages 52–99) were dissected. Cutaneous SLA depth, lumen diameter, external diameter, plane, and common variable location at pre‐determined points in the lip and nasolabial fold regions were measured. These points included the SLA branch point (from the facial artery), P1 (labial commissure), P2 (midpoint between labial commissure and peak of Cupid's bow), P3 (peak of Cupid's bow), and P4 (midline). ANOVA, independent samples t‐tests, and paired samples t‐tests were conducted to compare measurements between sites.

Results

The lumen diameter of the SLA was largest at point P1 (labial commissure; 0.85 ± 0.34 mm) and smallest at point P4 (midline; 0.56 ± 0.21 mm). The SLA branch point was found to have the deepest mean cutaneous depth (5.49 ± 1.95 mm), while point P2 (midpoint between the labial commissure and the peak of Cupid's bow) was found to have the most superficial mean cutaneous depth (4.29 ± 1.54 mm). There were no significant differences between left and right hemifaces as well as between male and female arterial parameters.

Conclusions

All SLA parameters should be interpreted carefully; for example, the point with the largest mean external diameter (P1; labial commissure) represents a greater chance of needle contact, but the point with the smallest mean lumen diameter (P4; midline) represents a smaller bolus of filler required to occlude the arterial lumen. Commonly used 27‐gauge filler needles are 0.41 mm in diameter; since the smallest mean lumen diameter was 0.56 mm (P4; midline), this means that the needle could potentially enter the lumen of the SLA and result in intra‐arterial injection at any point along the SLA course from its origin to the midline. Overall, the SLA's variable, superficial, and large‐caliber course places it at significant risk for intra‐arterial injection with dermal filler at all points in its course.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.