A split flap technique shifting the location of perforator entry point to lengthen the pedicle of a multiple perforator based free flap.

BACKGROUND: Pedicle length deficiency in microsurgical procedure is a challenging issue. The aim of this report is to present a case series of a flap-splitting technique for pedicle lengthening of large multiple perforator-based (MPB) free flaps. METHODS: In this retrospective case series, we reviewed the medical records of patients who underwent free flap repair with "split flap" pedicle-lengthening technique between August 2017 and December 2021. Main outcome measures included patient demographics, indications, defect size, flap type, additional vascular pedicle length, and flap survival. RESULTS: Data from 16 patients (age 38-78 years) were reviewed. Indications included breast reconstruction, repair of scalp malignancy or titanium mesh implant exposure, and repair of burn scar contracture. Flaps included ALT flap, LD flap and DIEP flap. The mean added pedicle length was 3.8 cm. Fifteen flaps survived completely and one flap was necrotic distally. No major complications occurred. CONCLUSIONS: The 'split flap' technique could be an effective remedy for unexpected pedicle length deficiencies in large MPB free flaps.

Three End-to-End Techniques for Microvascular Anastomosis of Vessels With Different Size Discrepancy.

BACKGROUND: Size discrepancy in microvascular anastomosis is a common issue in free flap transfer and replantation surgery. A number of different techniques have been described to overcome the problem, but optimal method continues to be defined. METHODS: Since June 2015 to May 2018, clinical courses of 103 microvascular cases performed by one senior surgeon were reviewed. Three end-to-end techniques including mechanical dilation, single-mattress suture, and wedge resection were applied in 364 anastomoses with caliber ratio between 1:1 and 1:1.5, 1:1.5 and 1:2, and 1:2 and 1: 3, respectively. RESULTS: A total of 112 flaps were incorporated in this study. The incidence of anastomotic failure was 3.0% (11/364), and the overall flap failure rate was 3.6% (4/112). The failure cases included 2 replanted scalps, 1 replanted ear, and 1 superficial temporal artery flap for nasal reconstruction. CONCLUSIONS: Our results depicted operational convenience and reliability of the 3 end-to-end anastomotic techniques in addressing mild-to-large vessel discrepancy.

The perforator flap from the contralateral large healthy breast as an alternative for breast reconstruction or combined breast and thoracic reconstruction.

BACKGROUND: It has been demonstrated that contralateral breast tissue can be used for delayed breast reconstruction. The current report presented the clinical outcomes of the perforator flap from the contralateral lower breast as a pedicled flap for immediate or delayed breast reconstruction and as a free flap for delayed breast reconstruction or simultaneous breast and thoracic reconstruction in patients with macromastia. METHODS: From June 2014 to August 2018, a total of 15 female patients with a mastectomy defect on one side and a large healthy breast on the other side were collected in our department. The pedicled flap based on the fourth internal thoracic artery perforator from the healthy breast was harvested for three immediate breast reconstructions and five delayed breast reconstructions. The free flap with the thoracoacromial vascular pedicle from the contralateral breast was transferred to the defect side for three delayed breast reconstructions and four simultaneous breast and thoracic reconstructions. RESULTS: The flap sizes ranged from 9 × 26 to 20 × 40 cm. All flaps survived well postoperatively. Two patients developed delayed wound healing problems on the reconstructed breast. No patient had complications with reduction mammaplasty. The mean follow-up for patients was 21 months, with no tumor recurrence in either breast. The patients were satisfied with the reconstruction even though a certain degree of asymmetry was observed in all cases. CONCLUSION: For patients with a large healthy breast, the contralateral breast is an alternative tissue source for breast reconstruction or combined breast and thoracic reconstruction.

Classification and Management of Polyacrylamide Gel Migration After Injection Augmentation Mammaplasty: A Preliminary Report.

BACKGROUND: Polyacrylamide gel (PAAG) migration after esthetic breast injection is clinically variable and complex, and thus, the rate of incomplete removal after debridement is high. OBJECTIVES: We aimed to describe a practical classification system for PAAG migration after breast injection and evaluate the outcome of our management. METHODS: A retrospective review of medical records was conducted for patients who presented to our institution for the management of PAAG migration after injection augmentation mammaplasty from June 2013 to November 2018. PAAG migration was evaluated by MRI examination and classified based on the migrating direction outside the breast contour. Surgery was performed to remove the material completely through different incisions. RESULTS: Seventy-eight women met the study criteria, with 106 breasts identified as showing PAAG migration. Patients were classified as having superior (22%), lateral (25%), inferior (34%), medial (10%) or complex (9%) PAAG displacement. The mean follow-up was 9 months (range 3-18 months). Postoperative complications included seroma (n = 3), delayed wound healing (n = 2), occasional breast pain (n = 5) and paresthesia or numbness at the migrated site (n = 2). MRI re-examination revealed that most of the injected material was removed, and no patient needed a secondary debridement operation. CONCLUSION: PAAG migration after injection augmentation mammaplasty can be clinically characterized into different types based on the migrating direction. It is helpful to perform MRI examinations preoperatively to fully evaluate PAAG migration. Under the guidance of our classification system, the injected material could be effectively eradicated with an acceptable complication rate. 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 .

Long-Term Safety and Efficacy of Botulinum Toxin A Treatment in Adolescent Patients with Axillary Bromhidrosis.

BACKGROUND: For adolescent bromhidrosis, the long-term safety and efficacy of botulinum toxin type A (BTX-A) treatment are not clear to date. PATIENTS AND METHODS: From June 2011 to July 2016, 62 adolescent patients with primary axillary bromhidrosis were recruited and 50 U of BTX-A was administered in each axilla. Repetitive injections were performed when the malodor returned. RESULTS: The average follow-up was 2.64 years. There were no reported local or systemic adverse effects. After the first BTX-A injection, 61.3% of patients (38/62) maintained the duration of more than 4 weeks. Of these patients, 21 patients underwent two sessions, 8 patients underwent three sessions, and 4 patients underwent four sessions. Twenty-four of sixty-two (38.7%) of patients had the duration of < 4 weeks. The second injection with the same dose was immediately administered, and the resulting duration increased to 9 weeks. Nineteen patients received the third injection with 100 U per underarm, and the resulting duration was extended up to 16 weeks. Overall, 82% of patients (51/62) ranked the BTX-A treatment to be very good or good. CONCLUSION: For adolescent axillary bromhidrosis, BTX-A injection is safe and effective over a long-term follow-up. The duration of efficacy is variable, and the dosage should be fine-tuned based on the individual response. 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 .

Ectopic implantation of an avulsed scalp with a tissue expander on a forearm for combined total scalp avulsion and spine injuries: A case report.

Total scalp avulsion with severe cervical spine injury is a contraindication for emergency replantation of the scalp to its anatomical site. We describe a case involving the ectopic implantation of an avulsed scalp on the forearm. A 41-year-old woman presented with severe total scalp avulsion and tears in the intervertebral discs at the C4/5 and C5/6 levels. The avulsed scalp was ectopically implanted on the left forearm with a tissue expander to provide support. Two-stage replantation of the scalp at its anatomical site was performed 19 and 40 days later. Replantation was successful, and the avulsed tissue exhibited excellent viability. In conclusion, this case shows that the ectopic implantation of the avulsed scalp on the forearm may be an option for total scalp avulsion with cervical spine injury.

Immediate nipple reconstruction with thoracodorsal artery perforator flap in breast reconstruction by latissimus dorsi myocutaneous flap in patients with Poland's syndrome.

Loss of long-term projection is the major disadvantage of nipple reconstruction using local flaps. We report a technique of immediate perforator flap nipple reconstruction in breast reconstruction by latissimus dorsi (LD) myocutaneous flap in patients with Poland's syndrome. From March 2007 to July 2012, 12 female patients (age range, 15-21 years) underwent breast reconstructions and immediate nipple reconstructions. A thoracodorsal artery perforator (TAP) flap was simultaneously raised on the LD muscle flap and folded by itself to form the nipple. Both the LD flap and TAP flaps survived postoperatively. The nipple projection was measured by a caliper, and the average loss was 29% by the 1-year follow-up. Eleven patients considered the aesthetic appearance of reconstructed breast and nipple to be very good or good. The immediate nipple reconstruction with TAP flap could be safely performed and results in considerable satisfaction in breast reconstruction by LD myocutaneous flap in patients with Poland's syndrome.

Growth factor therapy in patients with partial-thickness burns: a systematic review and meta-analysis.

Growth factor (GF) therapy has shown promise in treating a variety of refractory wounds. However, evidence supporting its routine use in burn injury remains uncertain. We performed this systematic review and meta-analysis assessing randomised controlled trials (RCTs) to investigate efficacy and safety of GFs in the management of partial-thickness burns. Electronic searches were conducted in PubMed and the Cochrane databases. Endpoint results analysed included wound healing and scar formation. Thirteen studies comprising a total of 1924 participants with 2130 wounds (1131 GF receiving patients versus 999 controls) were identified and included, evaluating the effect of fibroblast growth factor (FGF), epidermal growth factor (EGF) and granulocyte macrophage-colony stimulating factor (GM-CSF) on partial-thickness burns. Topical application of these agents significantly reduced healing time by 5·02 (95% confidence interval, 2·62 to 7·42), 3·12 (95% CI, 1·11 to 5·13) and 5·1 (95% CI, 4·02 to 6·18) days, respectively, compared with standard wound care alone. In addition, scar improvement following therapy with FGF and EGF was evident in terms of pigmentation, pliability, height and vascularity. No significant increase in adverse events was observed in patients receiving GFs. These results suggested that GF therapy could be an effective and safe add-on to standard wound care for partial-thickness burns. High-quality, adequately powered trials are needed to further confirm the conclusion.

Prolonging the duration of masseter muscle reduction by adjusting the masticatory movements after the treatment of masseter muscle hypertrophy with botulinum toxin type a injection.

BACKGROUND: Botulinum toxin type A (BTX-A) is widely used for the clinical treatment of masseteric hypertrophy. Until now, few reports have discussed how to prolong the duration of its effectiveness. OBJECTIVE: This study evaluated that purposely adjusting the masticatory movements is possible of postponing the masseter muscle rehypertrophy. METHODS: Ninety-eight patients were randomly and equally divided into 2 groups, and 35 U BTX-A per side was injected into the masseters. The thickness and volume of the masticatory muscles were measured by ultrasound and computerized tomography, respectively. Patients in Group 1 were instructed to strengthen their masticatory effort during the denervated atrophic stage of the masseter (the interval was evaluated by real-time ultrasound monitoring), whereas patients in Group 2 were not given this instruction. When the masseter muscle began to recover, patients in both groups were instructed to reduce their chewing. RESULTS: The duration of the masseter muscle rehypertrophy was significantly prolonged in Group 1 patients. The thickness and the volume of the other masticatory muscles were significantly increased in Group 1 but were either slightly decreased or insignificantly different in Group 2. CONCLUSION: Purposely strengthening masticatory muscle movement during the denervated atrophic stage of the masseter can prolong the duration of masseter rehypertrophy.

Incidence and Features of Vertebral Fractures After Scalp Avulsion Injuries.

BACKGROUND: Scalp injuries are usually extensive and may have a deleterious impact for the patient. To date, little is known in the literature about simultaneous vertebral fractures. The aim of this study was to analyze the frequency, features and pathogenesis of vertebrae fractures after scalp avulsion injuries. METHODS: Between 2004 and 2014, 64 patients were retrospectively identified after scalp avulsion injuries. Patient records were reviewed for mechanism of trauma, clinical examination and neurological deficits. The features of vertebral fractures were evaluated by X-ray, computed tomography or magnetic resonance imaging, where necessary. Various treatment options were evaluated according to their injuries. RESULTS: Totally, 6 women (9.4%) with a mean age 37 ± 6 years were identified with cervical fractures due to scalp avulsion injuries (mean size defect 808 ± 56 cm). Clinical examination revealed neurological deficits in 3 patients. Five patients were diagnosed with different types of C2 fracture and 1 patient was diagnosed with C7 fracture. One patient had simultaneous fractures of T3/T4. Treatment for the scalp avulsion consisted in either composite graft in 5 patients or microsurgical replantation in 1 patient. The vertebral fractures were treated by collar protection (3), cervical traction (1), HALO fixation (1), and internal stabilization (1), respectively. CONCLUSIONS: Most vertebral fractures associated with scalp avulsion injuries are C2 fractures. Careful and appropriate examination is mandatory for patients with scalp avulsion injuries to exclude vertebral fractures which, if not recognized early, can have serious and devastating consequences.

Achieving Symmetry in Unilateral DIEP Flap Breast Reconstruction: An Analysis of 126 Cases over 3 Years.

Many patients who prefer breast reconstruction by a deep inferior epigastric artery perforator (DIEP) flap often lack skin laxity at the lower abdomen. Recreating a symmetrical breast with various degrees of ptosis is one of the most difficult procedures. In this report, varied DIEP flap shapes were precisely designed on the basis of normal breast ptosis. The reconstructive outcomes were quantitatively evaluated for asymmetry of footprint, volume, breast projection, and nipple position by a 3-dimensional scanning system. One hundred twenty-six cases of unilateral DIEP flap breast reconstruction were successfully performed from January 2009 to July 2012. The maximal flap width ranged from 7.5 to 10.5 cm (mean, 9.0 cm), and the flap length ranged from 28 to 38 cm (mean, 32.5 cm). The discrepancy of the footprint and nipple position did not differ significantly between the reconstructed and normal breasts. However, the reconstructed side had significantly higher breast volume and projection. For patients with a relatively tight abdomen, the flap design and shaping approach we propose achieves a maximal symmetrical outcome and should be considered as a good and reliable option.

Efficacy and safety profile of antibiotic prophylaxis usage in clean and clean-contaminated plastic and reconstructive surgery: a meta-analysis of randomized controlled trials.

BACKGROUND: There is no consensus with regard to antibiotic prophylaxis usage in clean and clean-contaminated plastic and reconstructive surgery. This meta-analysis sought to assess the efficacy and safety of antibiotic prophylaxis and to determine appropriate duration of prophylaxis. METHODS: An English language literature search was conducted using PubMed and the Cochrane Collaboration for randomized controlled trials (RCTs) that evaluate the use of antibiotic prophylaxis to prevent postoperative surgical site infection (SSI) in patients undergoing clean and clean-contaminated plastic and reconstructive surgery. Data from intention-to-treat analyses were used where available. For the dichotomous data, results for each study were odds ratio (OR) with 95% confidence interval (CI) and combined for meta-analysis using the Mantel-Haenszel method or the DerSimonian and Laird method. Study quality was critically appraised by 2 reviewers using established criteria. STATA version 12 was used for meta-analyses. RESULTS: Twelve RCTs involving 2395 patients were included, of which 8 trials were considered to be of high methodological quality. Effect of antibiotic prophylaxis in plastic and reconstructive surgery was found favorable over placebo in SSI prevention (13 studies; 2449 participants; OR, 0.53; 95% CI, 0.4-0.7; P < 0.01) and the other wound complication (OWC) prevention (9 studies; 1843 participants; OR, 0.36; 95% CI, 0.15-0.84; P < 0.02). Subgroup analysis performed according to surgical wound type or the duration of prophylaxis did not modify the results except for the OWC with short-term antibiotic treatment. Compared with short-term antibiotic prophylaxis, long-term administration showed no evidence of a difference in risk of SSI (7 studies; 1012 participants; OR, 0.99; 95% CI, 0.63-1.55; P < 0.95), OWC (5 studies; 824 participants; OR, 0.92; 95% CI, 0.46-1.86; P < 0.82), and adverse event relative to antibiotic administration (3 studies; 653 participants; OR, 0.23; 95% CI, 0.01-4.92; P < 0.35). CONCLUSIONS: This meta-analysis of RCTs provides evidence supporting that antibiotic prophylaxis reduced postoperative SSI in clean plastic surgeries with high-risk factors and clean-contaminated plastic surgeries. Besides, a short-course administration regimen seemed to be of adequate efficacy and safety. High-quality prospective trials on larger scale are needed to further confirm these findings.

Angioarchitecture of extracranial arteriovenous malformations: a vascular casting study.

PURPOSE: Arteriovenous malformations (AVMs) are congenital vascular anomalies, not proliferative neoplasms, but tend to behave aggressively with unpredictable growth and tissue destruction. For the understanding of the angioarchitecture of extracranial AVM, which is believed to be the main cause that explains all presenting symptoms, the study aimed to elucidate the vascular structure of extracranial AVM with vascular cast of completely excised AVM lesion. METHODS: From 1996 to 2011, a total of 289 cases with extracranial AVM received surgical or surgery-based treatment by the authors in the department, excluding cases that received embolization alone. Among them, 10 patients (4 female cases, 6 male cases) were involved in this study. All the AVM nidi were excised and injected with resin through feeding arteries, then the corrosion casts were made for dimensional measurement. RESULTS: Arteriovenous malformation nidus was comprised of multilevel branched blood vessels. We measured the diameter of predominant trunk and primary level branch vessels. The diameter of predominant trunk ranged from 2.0 (0.2) to 4.3 (0.2) mm, whereas primary level branch vessels from 1.0 (0.1) to 2.0 (0.2) mm. Seventy percent of AVM casts included trunk blood vessels with the maximal diameters ranged from 4 to 12 mm, and an average of 7.0 mm (SD, 0.93; n=10). In this series, the smallest blood vessel visible in the cast was approximately 0.2 mm in diameter, whereas balloon-like serious dilated vessels from 10.2 to 25.4 mm. CONCLUSIONS: Vascular casting study shows us more informative, realistic, and objective 3-dimensional angioarchitecture than digital subtract angiography, 3-dimensional computed tomography angiography, and magnetic resonance angiography, not only for the facilitation of treatment decision but also for the purpose of education and research.

Columella lengthening by a vascularized preauricular flap.

BACKGROUND: A short columella can result in significant cosmetic and functional deformities. Various techniques such as local flap transfer and composite grafts have been reported for columellar lengthening, but the overall results remain unsatisfactory. Transferring a local flap cannot provide new tissue for the columella, which limits its application. Composite grafting can provide new tissue volume, and the composite tissue from the preauricular region has an excellent color and texture match. However, the lack of a stable blood supply for the composite graft restricts its clinical application due to problems such as viability, dimensions, and atrophy. To overcome these limitations, the authors harvested a vascularized preauricular flap for columella lengthening. METHODS: Based on the superficial temporal vessels, the vascularized preauricular flap was harvested as a free flap and transferred to the columella region. The recipient vessels were angular vessels or facial vessels, and microsurgical anastomosis was performed between recipient vessels and the pedicle. The lateral femoral circumflex vessels were used as vascular grafts when the pedicle was not long enough. RESULTS: Eight patients who had short columellas were reconstructed with vascularized preauricular flaps. Six flaps were harvested in a reverse fashion, and the remaining two flaps were harvested in an anterograde direction. All the flaps survived well and showed a good color and texture match without hypertrophic scars. An average of 13.3 mm improvement in length was obtained for the eight patients. Two patients underwent a secondary debulking procedure to thin the flap. CONCLUSION: The free vascularized preauricular flap procedure is a reliable method for columellar lengthening and has wide clinical application. LEVEL OF EVIDENCE V: 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 .

Comparison of negative pressure dressing and conventional dressing in the management of skin grafts at the donor site of the latissimus dorsi flap.

INTRODUCTION: Delayed and incomplete healing of the skin graft at the donor site of an LD flap is common because of seroma formation. The authors aimed to evaluate whether the application of an NPD could improve the healing process after STSG at LD donor sites. MATERIALS AND METHODS: From July 2019 to September 2021, 32 patients underwent STSG with NPD at the LD donor site, and 27 patients underwent STSG with TBDs. Data were collected and analyzed using the chi-square test, t test, and Spearman correlation test. RESULTS: The overall Spearman correlations of graft loss with seroma, hematoma, and infection were 0.56 (P <.01), 0.64 (P <.01), and 0.70 (P <.01), respectively. Compared with the TBD group, the STSG take rate was significantly higher in the NPD group (90.3% vs 84.5%, P =.046) while the seroma rate (18.8% vs 44.4%, P =.033), graft loss (9.4% vs 29.6%, P =.047), and mean length of stay (10.9 ± 1.8 vs 12.1 ± 2.4, P =.037) were significantly lower. CONCLUSIONS: NPDs for STSG at the LD donor site contribute significantly to improved graft acceptance with reduced seroma formation.

Reconstruction of through-and-through facial defects with combined anterior tibial flap and dorsalis pedis flap.

Through-and-through facial defects can be the result of malignancy, malformations, or trauma and pose a challenge for reconstructive surgeons. An ideal reconstruction of such defects should restore both lining and external skin defects at the same time. In this report, we describe the use of combined anterior tibial flap and dorsalis pedis flap to reconstruct complex facial defects. Six patients who presented with through-and-through facial defects were included. The cause of defects were trauma, radiotherapy, or flap necrosis, and defect locations were the buccal (3 patients), oral region (2 patients), and frontal (1 patient). The outer defects were between 5 × 6 cm and 13 × 9 cm, whereas the inner defects were between 3 × 3 cm and 5 × 6 cm. The anterior tibial flaps that were used to cover the outer defects ranged from 5 × 8 cm to 10 × 15 cm, and the dorsalis pedis flaps that were used to reconstruct the lining ranged from 3 × 4 cm to 6 × 8 cm. Donor sites were covered with skin grafts. No flap failure was evident, and a good aesthetic outcome was obtained in all cases. In 1 patient, the skin graft on the dorsal pedis presented partial necrosis and ultimately healed by dressing change. Compared with other techniques, the combined anterior tibial flap and dorsalis pedis flap possesses the potential benefits of being thin and pliable and having reliable vascularity. It brings a new alternative method for complex facial defect reconstruction.

A modified technique combining excision of the levator muscle and tarsus for blepharoptosis in Asians: a 6-year experience with 116 cases.

BACKGROUND: In patients with blepharoptosis, the function of levator muscle is insufficient or completely absent, causing blepharoptosis in various degrees. For mild or moderate blepharoptosis, levator advancement or resection is commonly performed. However, in severe cases, undercorrection results and recurrence often occur even a great length of levator muscle is resected. Because the levator muscle makes the upper eyelid move in a physiologic direction, exerting the function of residual levator muscle is still a more preferred approach for correction of blepharoptosis. This study combined tarsus resection with levator resection. The resected tarsus can offset the amount of the levator excised, making this technique applicable for severe cases. METHODS: This study included 116 patients (175 eyelids) with moderate or severe ptosis who underwent combined excision of the levator muscle and the tarsus. For cases of bilateral blepharoptosis with different levator functions between the two eyelids, surgery was performed for more severe side first and for the other side 6 months later. Postoperatively, the correction and symmetry results were evaluated and analyzed using chi-square testing by SPSS (version 10.0). RESULTS: Adequate or normal correction was achieved in 149 eyelids (85.1%). The difference in correction results did not differ significantly between moderate and severe cases. With a two-stage operation, 98 patients (84.5%) obtained good or fair asymmetry results, and no statistically significant difference existed between the bilateral and unilateral cases. CONCLUSION: The described technique appears to be effective for both moderate and severe ptosis, with better biomechanics and a satisfying aesthetic outcome.

Using human hair follicle-derived keratinocytes and melanocytes for constructing pigmented tissue-engineered skin.

BACKGROUND: Traditional tissue-engineered skin does not produce a satisfactory long-term result because it lacks natural skin pigmentation and leads to discolored cosmetically unpleasing skin that only functions to cover the body of patients. Additionally, the cell sources for tissue-engineered skin are generally derived from normal skin, which is often limited in patients with skin defects. METHODS: In this study, hair follicle melanocytes and keratinocytes were isolated from human scalp. The melanocytes were co-cultured with keratinocytes until the second passage and then purified. Purified melanocytes and keratinocytes were seeded onto the chitosan-gelatin membrane for 1 week to construct pigmented tissue-engineered skin. The pigmented skin equivalent was used to resurface the skin defect in nude mice. Four weeks after grafting, skin biopsies were harvested to take hematoxylin and eosin staining and immunohistochemistry staining of Melan-A and HLA-ABC. RESULTS: Large quantities of purified melanocytes can be obtained with co-culture method. The hematoxylin and eosin staining of repaired skin biopsy demonstrated that the tissue-engineered skin can repair skin defects successfully. Engineered skin contained pigmentation and stained positive for Melan-A and HLA-ABC, which confirmed the presence of melanocytes and its sources were of human origin. CONCLUSION: This study demonstrated the possibility of constructing pigmented tissue-engineered skin with human hair follicle-derived keratinocytes and melanocytes, which brings a promising method to make up for the deficiency of traditional tissue-engineered skin and provides an alternative treatment for depigmentation diseases.

Characteristics of emergency room visits in patients with facial injuries in mainland China during the 60-day level I emergency response to COVID-19.

Chinese mainland launched the 60-day first-level response to major public health emergencies during the COVID-19 outbreak. This study aimed to determine the incidence and describe the characteristics and predictors of patients who presented to the emergency department (ED) with facial trauma during this period. A retrospective review was conducted on the basis of data on facial trauma presented at the ED of XXX Hospital from 24 January 2020 to 23 March 2020 and the same period in the previous two years. Multivariate linear regression model was employed to explore potential determinants associated with daily number of facial trauma. Significant reduction was observed in the amount of facial trauma during the COVID-19 level I emergency response. The trauma volume evenly distributed over the week. The declined most significantly by age group, 20-29 years, and by time range of visit, 00:00-08:00. Multivariate regression analyses revealed positive relationship between daily minimum temperature and facial trauma volume. The number of facial injuries decreased significantly during the COVID-19 Level 1 emergency response, with the least reduction in total daytime facial trauma and in infant and child facial trauma. And a higher minimum temperature may lead to increased number of facial trauma presentations.

Influence Mechanism of Silicon on Carbide Phase Precipitation of a Corrosion Resistance Nickel Based Superalloy.

The effect of silicon on diffusion behavior of the carbide forming elements in Ni-Mo-Cr-Fe based corrosion-resistant alloy is studied by diffusion couple experiment. One group of diffusion couples are made of the alloy with a different silicon content, another group of diffusion couples are made of pure nickel and the alloy with different silicon content (0Si, 2Si). Two groups of alloys with same silicon content and different carbon content are also prepared, the microstructure of solution and aging state of these two groups alloys are analyzed, and their stress rupture properties are tested. The effect of silicon on the diffusion of alloy elements and the interaction effect of carbon and silicon on the microstructure and stress rupture properties of the alloy are analyzed. The mechanism of Si on the precipitation behavior of carbide phase in Ni-Mo-Cr-Fe corrosion resistant alloy is discussed. The results show that silicon can promote the diffusion of carbide forming elements and the formation of carbide. The precipitation behavior of the secondary phase is the result of the interaction effect of silicon and carbon, and is related to the thermal history of the alloy. Combined with the characteristic of primary carbides, it is confirmed that the precipitation of M12C type secondary carbide is caused by the relative lack of carbon element and the relative enrichment of carbide forming elements such as molybdenum. The stress rupture properties of two silicon-containing alloys with different carbon contents in solution and aging state are tested. The stress rupture life of low carbon alloy is lower compared with high carbon alloy at solution state, but after aging treatment, the stress rupture life of low carbon alloy is significantly improved, and higher than that of high carbon alloy. The main aim of this research is to reveal the influence mechanism of silicon on carbide phase precipitation of a Ni-Mo-Cr-Fe based corrosion-resistant superalloy, which provides theoretical basis and reference for later alloy design and engineering application.