ABSTRACT
Keloid scars tend to occur in high-tension sites due to mechanical stimuli that are involved in their development. To date, a detailed analysis of keloid distribution focused specifically on facial and neck areas has not been reported, and limited literature exists as to the related mechanical factors. To rectify this deficiency of knowledge, we first quantified the facial and neck keloid distribution observed clinically in 113 patients. Subsequently, we performed a rigorous investigation into the mechanical factors and their associated changes at these anatomic sites in healthy volunteers without a history of pathologic scarring. The association between keloid-predilection sites and sebaceous gland-dense and acne-prone sites was also examined. To assess skin stretch, thickness and stiffness, VECTRA, ultrasound and indentometer were utilised. Baseline skin stiffness and thickness were measured, as well as the magnitude of change in these values associated with facial expression and postural changes. Within the face and neck, keloids were most common near the mandibular angle (41.3%) and lateral submental (20.0%) regions. These areas of increased keloid incidence were not associated with areas more dense in sebaceous glands, nor linked consistently with acne-susceptible regions. Binomial logistic regression revealed that changes in skin stiffness and thickness related to postural changes significantly predicted keloid distribution. Skin stiffness and thickness changes related to prolonged mechanical forces (postural changes) are most pronounced at sites of high keloid predilection. This finding further elucidates the means by which skin stretch and tension are related to keloid development. As a more detailed analysis of mechanical forces on facial and neck skin, this study evaluates the nuances of multiple skin-mechanical properties, and their changes in a three-dimensional framework. Such factors may be critical to better understanding keloid progression and development in the face and neck.
ABSTRACT
BACKGROUND: Soft-tissue defects in the hand and digits can be effectively covered by using the free superficial palmar branch of the radial artery (SPBRA) flap, which is harvested from the radial volar wrist. Because previous anatomical studies on this flap are limited, multidetector-row computed tomographic angiography of the upper limbs was conducted to characterize the three-dimensional anatomical structure of the SPBRA and its perforators in living patients. METHODS: This retrospective anatomical study was conducted from 2014 to 2019. All data from Digital Imaging and Communications in Medicine were analyzed by using their viewer. SPBRA diameter and the location where it bifurcated from the radial artery were recorded, as were the number, location, branching patterns, and diameters of its perforators and their lengths. RESULTS: In total, 30 patients met all eligibility criteria. All had the SPBRA. The vessel bifurcated from the radial artery on average 13.2 mm proximally from the radial styloid process. The 30 patients had 40 SPBRA perforators in total. Their average SPBRA-to-dermis length was 6.43 mm. All patients had at least one direct cutaneous perforator. Nine and one also had one musculocutaneous perforator and another direct perforator, respectively. All direct cutaneous perforators were located inside a 16.4-mm-diameter circle with an origin on the scaphoid tubercle. The mean diameters of the SPBRA and its perforators were 1.12 and 0.62 mm, respectively. CONCLUSIONS: All patients had at least one reliable SPBRA perforator in the radial volar wrist. The authors' results suggest that plastic surgeons can easily and safely plan the SPBRA flap design, potentially without preoperative perforator mapping.
