Ishii Nobuaki, Akaishi Satoshi, Akimoto Masataka, Ichinose Shizuko, Usami Satoshi, Dohi Teruyuki, Ogawa Rei
From the Department of Plastic Surgery, Nippon Medical School Chibahokusoh Hospital, Inzai City, Chiba Prefecture, Japan.
Department of Plastic, Reconstructive and Regenerative Surgery, Graduate School of Medicine, Nippon Medical School, Bunkyo Ward, Tokyo, Japan.
Plast Reconstr Surg Glob Open. 2024 Dec 20;12(12):e6365. doi: 10.1097/GOX.0000000000006365. eCollection 2024 Dec.
Almost half of all spontaneously occurring keloids are acne keloids on the anterior chest. These keloids often grow in a crab-claw shape due to predominant tractional stresses on the scar; such stresses are risk factors for keloid growth/progression. To understand the relationship between acne keloid growth and mechanical stress, we conducted finite element analysis (FEA), measured the long/short dimensions of photographed acne keloids, and subjected acne keloids to microscopy.
FEA was conducted on 10 identically shaped ellipsoidal keloids whose long-axis length rose from 5 to 50 mm in 5-mm increments. They were embedded in the skin and subjected to traction. The stress on the keloid and its surrounding tissues was determined. Dimensions of 220 acne keloids were measured. Electron/light microscopy was conducted on the center, margins, and surrounding tissues of chest acne keloids.
FEA showed that as the keloid "grew," the tractional stress centered on its core, then became evenly distributed, and then focused increasingly on the tractioned keloid margin, especially its shallow dermis. This is associated with increasing stress in the surrounding tissues at the keloid margin. Clinical dimension measurements showed that acne keloids remained round until 4-5 mm, after which they elongated rapidly. Electron microscopy showed that in the surrounding skin, fragments of keratinocyte, fibrin, and numerous cell fragments were observed just below the epidermal basement membrane.
Keloid-prone acne should be treated with steroid tape or other keloid therapy when it reaches 4-5 mm in diameter.
所有自发性瘢痕疙瘩中，近一半是前胸的痤疮瘢痕疙瘩。由于瘢痕上主要的牵张应力，这些瘢痕疙瘩常呈蟹爪状生长；此类应力是瘢痕疙瘩生长/进展的危险因素。为了解痤疮瘢痕疙瘩生长与机械应力之间的关系，我们进行了有限元分析（FEA），测量了拍摄的痤疮瘢痕疙瘩的长/短尺寸，并对痤疮瘢痕疙瘩进行了显微镜检查。
对10个形状相同的椭圆形瘢痕疙瘩进行有限元分析，其长轴长度以5毫米的增量从5毫米增加到50毫米。将它们嵌入皮肤并施加牵引力。确定瘢痕疙瘩及其周围组织上的应力。测量了220个痤疮瘢痕疙瘩的尺寸。对胸部痤疮瘢痕疙瘩的中心、边缘和周围组织进行了电子/光学显微镜检查。
有限元分析表明，随着瘢痕疙瘩“生长”，牵张应力集中在其核心，然后变得均匀分布，然后越来越集中在受牵拉的瘢痕疙瘩边缘，尤其是其浅真皮层。这与瘢痕疙瘩边缘周围组织中应力的增加有关。临床尺寸测量表明，痤疮瘢痕疙瘩在4-5毫米之前保持圆形，之后迅速拉长。电子显微镜显示，在周围皮肤中，在表皮基底膜下方观察到角质形成细胞、纤维蛋白和许多细胞碎片。
直径达到4-5毫米的易形成瘢痕疙瘩的痤疮，应用类固醇胶带或其他瘢痕疙瘩治疗方法进行治疗。
