Dermatology Department, Faculty of Medicine, Cairo University, 59 Street 104, Maadi Gardens, Cairo, 11431, Egypt.
Ophthalmology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
Lasers Med Sci. 2019 Aug;34(6):1125-1135. doi: 10.1007/s10103-018-02700-5. Epub 2019 Jan 4.
Fractional CO laser rejuvenation of scars offers a high safety profile. Laser marks usually disappear clinically within 1 week. The authors observed occasional persistence of the laser marks on the scar surface. The purpose of this study is to report the incidence and to describe the clinical, dermoscopic, and histological features of a novel observed complication of fractional CO laser scar rejuvenation "Persistent Pixel Stamping Marks (PPSM)".One hundred seventy-one cases were consecutively recruited from patients assigned for fractional CO laser scar rejuvenation. Patients who developed the phenomenon 1 month post laser session were recorded and subjected to clinical photography, dermoscopy, and optical coherence tomography (OCT) as well as a 4-mm punch biopsy from pixelated scars. The evolution of PPSM was followed up for 6 months. PPSM developed in 16 patients (9.4%), 15 of which were post burn hypertrophic scars. PPSM was significantly related to darker skin type, darker scar color, and longer scar duration. Histopathological findings included characteristic holes in stratum corneum and superficial dermis, thick collagen bundles perpendicular to the skin surface with loss of elastic tissue, focal interface changes, and triangular focus of fibroblastic proliferation. The marks disappeared in 5 and lasted in 11 patients. Their longevity was significantly related to longer dwell times and lower densities. PPSM represent miniature scarring at the sites of the microscopic thermal zones or a sign of their delayed healing. They tend to follow fractional CO laser resurfacing of hyperpigmented, long-standing burn scars. Longer dwell times and lower densities make them last longer.
点阵 CO2 激光治疗瘢痕的安全性较高。激光标记通常在 1 周内从临床上消失。作者偶尔观察到激光标记在瘢痕表面持续存在。本研究的目的是报告这一并发症的发生率，并描述点阵 CO2 激光治疗瘢痕年轻化后一种新的观察到的并发症“持续像素压痕（PPSM）”的临床、皮肤镜和组织学特征。连续招募了 171 例接受点阵 CO2 激光瘢痕年轻化治疗的患者。记录了激光治疗 1 个月后出现该现象的患者，并对其进行了临床摄影、皮肤镜、光学相干断层扫描（OCT）以及从像素化瘢痕处进行 4mm 打孔活检。对 PPSM 的演变进行了 6 个月的随访。16 例（9.4%）患者出现 PPSM，其中 15 例为烧伤后增生性瘢痕。PPSM 与皮肤颜色较深、瘢痕颜色较深和瘢痕持续时间较长显著相关。组织病理学发现包括角质层和浅层真皮的特征性孔、垂直于皮肤表面的厚胶原束伴弹性组织丢失、局灶性界面改变和纤维母细胞增殖的三角形焦点。5 例患者的痕迹消失，11 例患者的痕迹持续存在。它们的持久性与较长的停留时间和较低的密度显著相关。PPSM 代表在微观热区部位的微型瘢痕形成，或其延迟愈合的标志。它们往往伴随着色素沉着、长期存在的烧伤瘢痕的点阵 CO2 激光磨皮治疗。较长的停留时间和较低的密度会使它们持续时间更长。
