Double Chin Concerns after En Bloc Mandibular U-Shaped Osteotomy: Submental-Cervical Soft Tissue Changes and Anterior Belly of Digastric Muscle Assessment.

OBJECTIVE: To assess submental-cervical soft tissue changes after en bloc mandibular U-shaped osteotomy and examine alterations in the anterior belly of digastric muscle (ABDM). METHODS: A retrospective study analyzed 20 patients who underwent en bloc mandibular U-shaped osteotomy from 2018 to 2023. Preoperative (Tp) and long-term follow-up (Tf) CT data were collected for analysis, measuring mandibular volume, soft tissue thickness at menton (Mes) and cervicale (C), and ABDM parameters (length, cross-sectional area (CSA), volume, distance from centroid point to the mandibular margin). Correlation analyses were performed to investigate the connection between soft tissue thickness changes, ABDM changes, and mandibular osteotomy volume. RESULTS: Long-term follow-up revealed a significant increase in soft tissue thickness at the Mes and C points after U-shaped mandibular osteotomy, especially at the C point. The adaptive length of ABDM decreased, CSA increased, and volume decreased, but the ABDM centroid point shifted downward relative to the mandibular margin, indicating drooping protrusion. The increment of soft tissue thickness was moderately positively correlated with the amount of osteotomy, and the decrement of ABDM length and volume were slightly positively correlated with the amount of osteotomy. CONCLUSION: The degree of soft tissue relaxation after U-shaped osteotomy is related to the extent of osteotomy. Notably, the protrusion of ABDM relative to the mandibular margin affects submental-cervical contour aesthetics. Prior to U-shaped osteotomy, it is crucial to assess the soft tissue condition of the patient's lower face, and the individualized design of the osteotomy volume should be carried out cautiously and safely. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Would hyaluronic acid-induced mental bone resorption be a concern? A prospective controlled cohort study and an updated retrospective cohort study.

BACKGROUND: Hyaluronic acid (HA) is a widely used filler for face contouring and is generally believed to be safe and effective. However, there have been reports of HA-related bone erosion in the chin area without clear scientific data regarding its existence, incidence, and severity. This exploratory study was to evaluate HA-related mental bone resorption through a prospective, controlled, observer-blind, nonrandomized clinical trial and a retrospective cohort study. METHODS: On the one hand, a prospective, controlled, nonrandomized, single-shot HA-injection clinical trial was conducted. Computed tomographic scans were collected at baseline and at 6-12 months of follow-up for both HA-injection and control groups. On the other hand, an updated retrospective cohort study compared the HA-injection with a blank control group. The primary outcomes composed of three quantitative parameters [bone resorption index (BRI M and BRI N ), bone resorption thickness ratio] and one subjective evaluation index (severity ranking). Information about demographics, complications, and injection volume were also recorded. RESULTS: From June 2021 to March 2023, 78 patients were prospectively recruited for the study. There was a significant association between HA-injection and bone resorption [BRI M : pre (84.24±8.10%) vs post (79.21±8.70%), P <0.001; BRI N : pre 92.50% (73, 144%) vs 87.99% (63, 132%), P <0.001; bone thickness ratio: HA 24.08% (0, 48%) vs control 0 (0, 17%), P <0.001]. However, there was no difference in large-volume (>1 ml) and small-volume (≦1 ml) injection subgroups [bone resorption thickness ratio: (21.50±10.91%) vs (24.51±11.92%), P =0.350]. The imaging manifestation revealed discernible bone resorption in 35.90% of the patients, with an median bone resorption thickness ratio of 24.08%. Between October of 2019 and March 2023, 95 HA-injection patients (190 semimandibular cases), 95 normal controls were enrolled. The BRI M was significantly lower in the HA-injection group compared to the controls ( P <0.001). CONCLUSIONS: HA may induce bone resorption in the mentum. Large-scale randomized controlled clinical trial is warranted for further confirmation. Patients should be informed of this potential complication.

The Influence of Extracellular Vesicles Secreted by Dural Cells on Osteoblasts.

To explore the influence of extracellular vesicles secreted by dural cells (Dura-EVs) on osteoblasts. Our methodology involves assessing the effects of these EVs at concentrations of 50ug/ml, 100ug/ml, and 200ug/ml on osteoblasts proliferation, differentiation, migration, osteogenesis, and inhibition of apoptosis. We also treated a cranial defect model with injections of these Dura-EVs and monitored the healing rate of cranial defects. Tissue sections were analyzed using Hematoxylin and Eosin (H & E), Masson's trichrome, and immunofluorescence (IF) staining. Our results suggest that Dura-EVs can enhance osteoblasts proliferation, migration, differentiation, and osteogenesis in a dose-dependent manner in vitro. In vivo, Dura-EVs may promote the repair of skull defects. Dura-EVs have an important influence on osteoblasts, our findings shed light on a novel aspect of the dura mater's contribution to cranial osteogenesis.

Successful Treatment and Long-term Follow-up of Parry-Romberg Syndrome with Anterolateral Thigh Adipofascial Flap.

BACKGROUND: Anterolateral thigh (ALT) adipofascial free flap transfer is a frequently used method to reconstruct the facial symmetry and restore facial soft-tissue contour in PRS patients. While its long-term prognosis and patient outcomes assessment are still lack of understanding. METHOD: The authors report their treatment experience in 42 patients between 2001 and 2017 using microsurgical free anterolateral thigh adipofascial flap transfer. The long-term follow-up results and final reconstructive outcomes were evaluated. RESULTS: A total of 42 patients were included. The follow-up ranged from 5 to 21 years. All patients were satisfied with the surgery. Photographic evaluation revealed significant enhancement of postoperative appearance. Numbness or hypesthesia of the local area was the most common symptom in the long-term follow up. CONCLUSION: This study has evaluated the long-term treatment results of Parry-Romberg disease with microsurgery using ALT free flap in our department. Over 20 years' experience and the significant enhancement of the overall appearance indicate a long-lasting, excellent outcome.

Redefining Mandibular Sub-units: The "ABC" Classification and Surgical Strategies for Lower Face Contouring.

BACKGROUND: In east Asia, lower face contouring surgeries including reduction mandibuloplasty and genioplasty are the most popular aesthetic craniofacial surgeries. Conventional selection of surgical strategies mainly relied on the visual judgment of the mandibular angle, without overall assessment of the mandibular sub-units. Furthermore, only a few studies offered quantitative assessment of the mandibular shape. METHODS: From 2010 to 2021, 1241 patients diagnosed with square faces and received customized lower face contouring surgeries by the senior author were reviewed and analyzed to propose an "ABC" classification system for facilitating surgical planning. RESULTS: Among them, 998 (80.42%) received bilateral mandible reshaping, 155 (12.49%) underwent bilateral mandible reshaping combined with genioplasty, and 88 (7.09%) received asymmetric mandible reshaping. A modified classification system composed of three critical parameters (height, morphology/thickness, divergence) in three aesthetic zones (mandibular angle, mandibular body, chin) was proposed based on quantitative summarization of the CT database and the senior author's 12-year experience. The way to facilitate surgical planning with this classification was demonstrated. CONCLUSIONS: This modified classification system ushered a decision-making process that prioritized several critical measurements and proposed an operative planning form. Meanwhile, it can also be cooperated into the three-dimensional virtual surgical plan. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

The Effect of Yes-Associated Protein on the Interaction Between the MEK/Extracellular Signal-Regulated Kinase and Hippo Pathways in Osteoblasts Co-Cultured With Fibroblast Growth Factor Receptor 2-Mutated Dura Cells.

BACKGROUND: C342Y (Cys342Tyr) point mutation of FGFR2 (fibroblast growth factor receptor 2) is closely associated with the pathogenesis of Crouzon syndrome. The dura mater plays an important role in mediating the closure of cranial sutures. However, the underlying mechanisms of these pathological processes have been rarely investigated. in this study, the authors analyzed the effects of dura cells with FGFR2 mutations on the biological function of osteoblasts. METHODS: Dura cells and cranial osteoblasts from C57BL/6 mice were extracted and cultured. C342Y-FGFR2 mutant constructs were established via lentivirus and applied to infect dura cells. A co-cultured trans-well system with dura cells and osteoblasts was established. Three experimental groups were set up: oste group, Oste + Dura-vector group, and Oste + Dura-C342Y group. The expression levels of key factors in MEK (Mitogen-activated protein kinase kinase, MAPKK)/extracellular signal-regulated kinase (ERK) and Hippo pathway were detected by western blot and RT-qPCR (Real Time Quantitative PCR). Finally, a rescue experiment was carried out with small interference RUA. RESULTS: The proliferation level of osteoblasts in Oste + Dura- C342Y group was significantly up-regulated. Our studies indicated that the activation of MEK/ERK pathway in Oste + Dura-C342Y group could inhibit the Hippo pathway, lead to down-regulation of large tumor suppressor 1 and promote the activation and nuclear localization of yes-associated protein, and the results of rescue experiments showed a reverse expression trend, further confirming the effects of C342Y-FGFR2 mutation in dura cells on osteoblasts and its potential mechanism. CONCLUSIONS: This study suggested that the C342Y-FGFR2 mutation in dura cells could promote osteoblastic proliferation, and shown the crosstalk between MEK/ERK and Hippo pathways. As the regulatory machinery center, yes-associated protein might play a bridging role in these pathways, and might influence the pathogenesis of craniosynostosis by activating downstream transcriptional factors.

Global and Chinese publications in plastic surgery journals between 2010 and 2020: a bibliometric analysis.

Background: Plastic surgery has evolved rapidly in recent years. We performed a bibliometric analysis of plastic surgery publications from 2010 to 2020 to evaluate global developments in plastic surgery and the Chinese contribution to this field. Methods: The 2020 Journal Citation Reports (JCR) was used to identify all plastic surgery journals; those that were available on the Web of Science database were retrieved and analyzed according to their number of published articles, citation rates, impact factors (IFs), research funding, and article references. We also determined the most popular journals for research from the 8 top-ranking countries in terms of contributed articles, including China. Results: From 2010 to 2020, 55,554 articles were published in the 35 selected plastic surgery journals. China, which contributed 9.48% of these articles, was the country with the second-highest number of articles published, a number which has been increasing annually. The average IF of Chinese articles was 1.74, with an average citation count of 6.68. These figures were significantly lower than those for articles from developed countries. China contributed 1,641 articles to the 10 highest impact plastic surgery journals. The Journal of Craniofacial Surgery was the most popular in terms of contributions by China. China had the highest rate of articles supported by funding (45.30%). The top 12 research-topic clusters were obtained by analyzing the references in the articles. Emerging research-topic trends worldwide and in China included fat grafting and blindness after filler injection. Conclusions: From 2010 to 2020, research into plastic surgery increased continuously, both worldwide and in China. However, the quality of the Chinese articles was lower than that of other top-ranked countries. Researchers who have elected to conduct research might consider emerging trends when designing future studies.

Surgical Result and Identification of FGFR2 Variants Using Whole-Exome Sequencing in a Chinese Family With Crouzon Syndrome.

ABSTRACT: Crouzon syndrome is considered as one of the most common craniosynostosis syndromes with a prevalence of 1 in 65,000 individuals, and has a close relationship with variants in fibroblast growth factor receptor 2. Here the authors described a Crouzon syndrome case, which was asked for surgery treatment for the symptom of multisuture craniosynostosis. Mild midfacial retrusion, larger head circumference, proptosis, pseudo-prognathism, and dental malposition could also be found obviously. Then fronto-orbital advancement and cranial cavity expansion were performed to the child. After whole-exome sequencing (WES) and Sanger sequencing, gene variants in the exons 2 and 3 of FGFR2 were detected. And protein tyrosine 105 replaced by cysteine in the extracellular region of FGFR2 was also detected. After operation, she presented a satisfactory anterior plagiocephaly and scaphocephaly correction, and the result was satisfied by surgeons and her parents. Variants detected using WES have further research prospect.

Dura cells in the etiopathogenesis of Crouzon syndrome: the effects of FGFR2 mutations in the dura cells on the proliferation of osteoblasts through the hippo/YAP mediated transcriptional regulation pathway.

BACKGROUND: FGFR2 (fibroblast growth factor receptor 2) mutations are implicated in the etiopathogenesis of syndromic craniosynostosis, and C278F- or C342Y-FGFR2 mutations can lead to Crouzon syndrome. The dura mater exerts crucial effects in the regulation of cranial suture development. However, the underlying mechanisms of these biological processes are rarely studied. This research explored and analyzed the biological function of FGFR2 overexpressed by dura cells on cranial osteoblasts. METHODS: Dura cells and cranial osteoblasts from C57BL/6 mice aged 6 days were obtained and cultured respectively. Lentivirus-FGFR2 constructs were engineered with C278F- and C342Y-FGFR2 mutations. The dura cells were infected with the constructs and co-cultured with osteoblasts in a trans-well system. Four experimental groups were established, namely the Oste group, the Oste+Dura-vector group, the Oste+Dura-C278F group, and the Oste+Dura-C342Y group. FACS, CCK8, and EdU assays were used to evaluate the osteoblast proliferation levels. Western blot and RT-qPCR were used to measure the expressions of the factors related to proliferation, differentiation, and apoptosis. Furthermore, the expression levels of the key factors in the Hippo/YAP-PI3K-AKT proliferation pathway were measured and analyzed. Finally, rescue experiments were performed with an RNA interfering assay. RESULTS: The proliferation and differentiation levels of the osteoblasts in the Oste+Dura-C278F and Oste+Dura-C342Y groups were significantly up-regulated, but the apoptosis levels in the four groups were not significantly different. The YAP, TEADs1-4, p-PI3K, and p-AKT1 expressions in the mutant FGFR2 groups were higher than the corresponding expressions in the control groups, and the results of the rescue experiments showed a reverse expression tendency, which further confirmed the effects of the FGFR2 mutations in the dura cells on the proliferation of the osteoblasts and the underlying possible mechanisms. CONCLUSION: Our studies suggest that the Crouzon mutations (C278F- and C342Y-) of FGFR2 in dura cells can enhance osteoblast proliferation and differentiation and might influence the pathogenesis of craniosynostosis by affecting the Hippo/YAP-PI3K-AKT proliferation signaling pathway.

Facial Contour Refining after Surgery-First SSRO with Computer-Assisted Design in East Asians.

BACKGROUND: Surgery-first sagittal split ramus osteotomies (SF-SSRO) are an effective treatment for patients with dental malocclusion. However, some patients with mandibular prognathism usually have facial deficiencies which cannot be corrected completely after orthognathic surgery. These are not accepted because the remaining facial contours are in disharmony. METHODS: Twenty-five patients, who were unsatisfied with their appearances after SF-SSRO and orthodontics, were included. The preoperative CTs were used to investigate patients for facial deformity. To achieve a harmonious facial contour, mandible long-curve osteotomy/mandible U-shaped osteotomy, genioplasty or facial autologous fat grafting was selected depending on patients' contour deformities with the assistance of CAD. RESULTS: Among the patients who underwent osteotomy, the gonial angle was improved from 111.16° ± 9 to 111.58° ± 9.06 after SF-SSRO because of distal fragment setback and rotation. After facial refine surgery, the gonial angle was significantly increased to 121.69°±2.41 (p < 0.05). And the mandibular width was decreased from 11.29 cm ± 0.44 to 10.45 cm ± 0.39 (p < 0.05) after mandibular outer plate griding. All patients were shown no signs of infection, massive bleeding, and osteonecrosis in the early stage. After follow-up time, they were all satisfied with their results and most of them recovered from lip numbness. CONCLUSIONS: This study indicated the clinical feasibility of two-stage orthognathic and facial bone contouring surgery for the treatment of dentofacial deformities. Two-stage facial contouring surgery can provide esthetic improvement for more accuracy in refining the facial contour. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Simple Dressing Fixation Method Following Harvest of the Ear Cartilage Graft.

ABSTRACT: Auricular cartilage is a common autologous graft material for rhinoplasty. Even though surgical techniques for the harvest of cartilage graft are well established, the management of the postoperative dressing fixation is still limited. Therefore, the authors propose a simple dressing fixation method in which gauze strips instead of gauze block or wet cotton, the suture of tie-over dressing fixed just through the cartilage rather than the full thickness of the auricle, a vaseline gauze interposed between the stitch knot and the skin and no additional pressure dressings postauricularly. No case of hematoma, infection and skin necrosis of the donor site was observed. This simple and reproducible technique provides perfect and homogeneous adhesion of the dressing all over the conchal cartilage while decreasing the risk of postoperative hematoma and discomfort.

What happens to an acellular scar matrix after implantation in vivo? A histological and related molecular biology study.

It has been established that scar acellular matrices (AMs), which allow cell proliferation, have similar characteristics. The aim of this study was to investigate the repair effect of scar AMs on animals, thus providing a reference for clinical application. Selected mature and immature scar AMs were implanted into animals, and then a negative control group was set for comparison. The effect of scar AMs on wound healing was observed through tissue staining, RT-qPCR, and immunohistochemistry. The materials showed milder inflammation and faster extracellular matrix (ECM) deposition than the negative control group. The ECM deposition and new vessels increased over time. However, the arrangement of ECM in mature scar AM was more regular than in immature scar AM and the negative control group, and more new vessels grew in the mature scar AM group than in the immature scar AM group and negative control group over the same period. The transforming growth factor-ß level was elevated at one month, two months, and six months. COLA1 and vimentin levels all peaked at six months. Matrix metalloproteinase and TIMP1 were also elevated at different months. Collectively, scar AMs can effectively promote wound healing and vascularization. Mature scar AMs have a better regeneration effect.

Unexpected Bone Resorption in Mentum Induced by the Soft-Tissue Filler Hyaluronic Acid: A Preliminary Retrospective Cohort Study of Asian Patients.

BACKGROUND: As one of the most commonly used soft-tissue fillers, hyaluronic acid is generally considered safe and efficacious. However, evident bone resorption in mentum was observed. In this study, the authors analyzed the impact of hyaluronic acid on bone resorption in mentum and the influencing factors. METHODS: The authors retrospectively compared the computed tomographic scans of patients with or without mentum augmentation using hyaluronic acid. The body mass index- and sex-matched control group was selected randomly. Semimandibular bone resorption index was calculated as the ratio of bone thickness in the incisive fossa to that in the mandibular symphysis. Injection volume, injection interval, the number of injections, product, complication were also recorded. RESULTS: From January of 2014 to June of 2019, 80 patients (160 cases) and 80 controls were recruited. The bone resorption index in the hyaluronic acid injection cohort was significantly lower than in the controls (75.25 ± 10.02 versus 82.86 ± 6.38; p = 0.000). Patients injected with greater than or equal to 1 ml per time were more susceptible to bone erosion compared with patients injected with less (68.89 ± 10.84 versus 76.49 ± 9.42; p = 0.000). There was no significant difference between one- versus multiple-injection groups and short-injection-interval versus long-injection-interval (≥6 months) groups. Furthermore, no reduced aesthetics were realized. CONCLUSIONS: Hyaluronic acid injection could induce bone resorption in the mentum; nevertheless, the aesthetics were not impaired. The severity of the bone loss was positively correlated with the injection volume per time; therefore, large-volume injection of hyaluronic acid should be performed with caution. The patients should be fully informed about this complication preoperatively. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Comparison of Bilateral Mandibular Angle Ostectomy Between East Asian Males and Females: A Study Based on Three-Dimensional Computed Tomography Reconstruction.

BACKGROUND: Mandibular angle ostectomy is a common plastic surgery for facial contouring in East Asians. However, rarely we could find reports on differences between East Asian males and females undergoing this surgery. OBJECTIVE: To describe the differences between East Asian males and females before and after mandibular angle ostectomy. METHODS: A total of 22 Asian males and 52 Asian females who underwent mandibular angle ostectomy from April 2015 to November 2018 were enrolled. Three-dimensional computed tomography was used to evaluate the preoperative and postoperative data of the mandible. Thirteen clinical data were measured on reconstructed mandibular models. The differences in data between males and females were analyzed to identify the causes of the differences before and after surgery. The follow-up was 6-12 months, and patient satisfaction was also evaluated. RESULTS: The ostectomy volume was positively correlated with the distance from the intersection of the occlusal plane and the anterior margin of the mandibular ramus to gonion (MR-Go; female, p < 0.01; male, p = 0.02). There was a positive correlation between the ostectomy volume and the postoperative drainage fluid (The drainage fluid is mainly blood) volume after surgery in females (p < 0.05), while there is no significant correlation between these two data in males (p = 0.19). Patients with a long distance from the second molar to the lower edge of the mandibular body (SM-MB) tended to have a higher risk of postoperative bleeding (female, r = 0.56, p < 0.01; male, r = 0.73, p = 0.01). CONCLUSION: Because of the difference in the anatomical size of the mandible and different aesthetic requirements for facial contouring between males and females, surgeons encounter different intraoperative conditions resulting in difficulties during surgery. Understanding differences in mandibular angles predicts differences in ostectomy volume and postoperative bleeding risk, thus aiding surgeons and leading to better operative outcomes. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

The Anatomy and Clinical Application of Preorbital Septum Fiber.

BACKGROUND: In patients with mild superior sulcus deformity, pseudoptosis, or multiple eyelid folds, several bulky fibers can be found anterior to the orbital septum. These fibers, called preorbital septum fibers, may constrict protrusion of the fat pad and movement of the levator palpebrae muscle. OBJECTIVES: In this study, the authors illustrated the anatomy of these fibers and described the double-eyelid procedure to correct pseudoptosis, mild superior sulcus deformity, and multiple eyelid folds, which may be caused by these fibers. METHODS: The bulky preorbital septum fibers were dissected and severed during upper blepharoplasty to release the orbital septum fat pad and levator palpebrae muscle. This procedure was performed between January 2016 and January 2018 in 56 patients with distinct preorbital septum fibers. RESULTS: Of the 56 patients, 38 displayed mild to moderate upper eyelid depression and multiple eyelids, and 18 displayed pseudoptosis. Bulky fibers that existed in the superficial layer of the orbital septum were all dissected and removed. After 6 months' recovery, the superior sulcus deformity improved in all patients. No recurrence of multiple eyelids was observed. Patients with pseudoptosis showed a notable release of their upper eyelids. CONCLUSIONS: This is the first time to our knowledge that the preorbital septum fibers are described as a distinct anatomical structure. They are clinically important in upper eyelid anatomy and the improvement of sunken upper eyelids or pseudoptosis. The combination of blepharoplasty with release of these fibers is easy to perform and promote.

En-Bloc U-Shaped Osteotomy of the Mandible and Chin for the Correction of a Prominent Mandibular Angle With Long Chin.

BACKGROUND: Lower face contouring surgery has become a popular aesthetic surgery in East Asian countries. Various surgical methods have been used to improve lower face aesthetics. When a patient has a wide as well as long lower face, procedures like chin polishing or T-type osteotomy are traditionally performed, but these surgical methods have several disadvantages. The authors devised a simple and reliable method to correct the wide and long lower face, without the complications associated with the traditional methods. METHODS: From July 2015 to January 2018, 30 patients with a prominent mandibular angle, long chin, and no malocclusion underwent en-bloc mandibular U-shaped osteotomy through an oral incision, in order to shorten the mandibular angle, body of the mandible, and the chin, and to improve the facial contour. The authors assessed the effectiveness of surgery through comparisons between pre- and postoperative radiographs, patient satisfaction, and surgical complications in the postoperative period. RESULTS: It was observed that all oral incisions healed by primary intention, and did not develop hematoma, infection, or osteonecrosis. Lower lip numbness occurred in 16 patients. After 6 to 12 months, all patients showed complete recovery from the numbness. All the patients were satisfied with their appearance after surgery. CONCLUSIONS: En-bloc mandibular U-shaped osteotomy is an improved form of mandibular surgery. The osteotomy line involves the whole mandible, which makes the length and width of the mandible considerably smaller. This surgery can effectively correct a prominent mandibular angle with long chin.

Preparation and characterization of human scar acellular dermal matrix.

INTRODUCTION: Acellular dermal matrix (ADM) is commonly used to treat burn injuries and wounds. In this study, we aimed to analyze the structural and biomechanical characteristics of an ADM from human scars. METHODS: We randomly selected human mature scars, human proliferative scars, and human normal skin as experimental specimens. Split-thickness dermal grafts were obtained using a free-hand graft knife. Samples were subjected to cell lysis to obtain ADMs. Structural analysis was performed via light microscopy, fluorescence microplate reader and scanning electron microscopy. Thereafter, human epithelial stem cells were incubated on these ADMs. Finally, the biomechanical characteristics of the ADMs were analyzed using a tensile machine. RESULTS: Normal skin ADM fibers were arranged in order, whereas proliferative scar ADM fibers were dense and disordered, and mature scar ADM fibers were porous and slightly disordered. The residual DNA of three ADM meet the residual DNA standard of biological material. After incubating human epithelial stem cells on ADMs, cells grew in an aggregated state in both normal skin ADMs and mature scar ADMs; however, cells adhered only on the surface of proliferative scar ADMs. No significant differences were observed in the Young's modulus, relaxation slope, creep slope, creep, or maximum tensile stress among the three ADMs, although significant differences in stress-strain elongation and relaxation were noted. CONCLUSIONS: Our findings showed that mature scar ADMs were similar to proliferative scar ADMs, showing a slight lag compared with normal skin ADMs, providing insights into the biomechanical features of these scar tissues. Abbreviations ADM Acellular dermal matrix H&E Hematoxylin and eosin PBS Phosphate-buffered saline SEM Scanning electron microscopy.