Novel anatomic description of the course of the perioral artery for minimally invasive treatments

Abstract

The facial artery (FA) arises from the external carotid artery, and passes onto the face as it crosses the mandible. And FA mainly supplies the perioral region, which is bounded by the nasolabial fold, the labiomental crease and the nasal base. Thus, in this study, the perioral artery (PA) was determined as distributing to the perioral region including the trunk of FA (from the mandible margin to the ala of nose, PA trunk), the superior labial artery (SLA), the horizontal labiomental artery (HLA) and the inferior labial artery (ILA). Dermal filler injection is a rapid way of eliminating wrinkles, smoothing acne scars, and enhancing volume. However, careless manipulation leading to PA damage during dermal filler injection could result in vascular complications such as lip and alar rim necrosis. The facial reconstruction helps a normal life for patients who have defects from cleft lip, oral cancer, and trauma. For facial reconstruction, various perioral flaps, such as the nasolabial flap, FAmusculomucosal (FAMM) flap and Abbé flaps have been performed. The success of these flap surgeries depends mainly upon the presence of an appropriate blood supply so the PA should be well grafted in the pedicle. However, most reported data about the PA does not provide delicate topographic information for minimal invasive procedure. Thus author performed the study with the following as its objects. The first aims of this study was to elucidate the distribution pattern of PA trunk and reproduce the whole course of PA trunk as a polynomial curve analysed by image processing, and suggest accurate references for various minimally invasive clinical procedures and facial reconstruction. The second aim of this study was to describe the various distribution patterns of the vascularization on the upper and lower lip area. The final aim of the study was to clarify the definition of the ILA and HLA, and to elucidate the significance of the HLA in the vascularization of the lower lip. For the study of reproducing the whole course of PA trunk, 59 adult hemifaces (21 bilateral and 17 unilateral; 26 males, 13 females; 46-95 years; mean age, 73 years) from 19 Korean and 20 Thai cadavers were used. For the study of the vascularization on the upper lip area, 60 hemifaces (24 bilateral and 12 unilateral; 24 males, 12 females; 46-95 years; mean age, 73 years) from 18 Korean and 18 Thai cadavers were used. For the study of the vascularization on the lower lip area, 63 hemifaces (26 bilateral and 11 unilateral; 24 males, 13 females; 46-95 years; mean age, 73 years) from 18 Korean and 19 Thai cadavers were used. The running course of the PA trunk along the PO line (a line connecting the mandible margin to the ala of nose) exhibited two patterns: oblique (78.0%, 46/59) or vertical (22.0%, 13/59). In the oblique pattern, the PA trunk proceeded along the PO line with two or three inflections, while in the vertical pattern it ran along the PO line but then turned medially near the mouth corner, giving off an alar branch parallel to the facial sagittal midline. The course of the PA trunk on the face can be predicted based on the following references: the PO line, the Rh point (the ramification point of the HLA, 5～10 mm medial to the PO line at the level of the middle of the lower lip portion), the Ra point (the ramification point of the alar branch (Ra point), 5～10 mm medial to the PO line at the level of lower one-third of the upper lip portion). While the PA trunk generally ran along the PO line, the PA trunk reflected medially at the Ra and Rh points. The branching point of SLA from FA, the S point, was located within a 1.5 cm sided square superolateral to the mouth corner. The S point may be estimated by placing a thumbnail beside the mouth corner. After the SLA branched from FA, it ran superior to the vermilion border under the orbicularis oris muscle, with a minimum depth of 3 mm. At the sagittal midline, the nasal septal branch ramified from the SLA and ran upward to the nasal septum along the sagittal midline. The HLA can be presented in the middle of the lower lip area inferior to the mouth corner, and be inclined gradually to the lower lip border near the facial midline (46.0%). ILA diverged from the FA or SLA at the level of the mouth corner. The HLA rather than ILA could be considered as the main artery supplying the lower lip mucosa.