Orthognathic surgery is a classic procedure to correct dentomaxillofacial deformities. Due to the complexity of the dentomaxillofacial anatomy, detailed and accurate surgical planning is usually required before the operation. With the rapid development of medical imaging technologies and surgical planning softwares in recent years, virtual surgical planning(VSP) has been increasingly applied in orthognathic surgery to provide more accurate, efficient and predictable planning and simulation. The design and development of VSP in orthognathic surgery involves image acquisition and composite head model construction, three-dimensional reference frame definition, virtual occlusion setup, virtual osteotomy and surgical simulation, soft tissue prediction and transfer tools. This paper summarizes the research of related steps for clinical reference.

Mesenchymal stem cells (MSCs) are a type of adult stem cells derived from the mesoderm, with the ability for self-renewal and multidirectional differentiation. Mesenchymal stem cell-derived exosomes (MSCs-Exo) are bioactive extracellular vesicles secreted by various MSCs into body fluids. They offer advantages such as anti-inflammatory properties, tissue repair, promotion of cell proliferation and differentiation, and regulation of the hair growth cycle. Hair regeneration involves the interaction of various cells and cytokines. Dermal papilla cells (DPCs) are considered as a unique MSCs with the functional properties of autologous stem cells. As the signaling center of the hair follicle, it plays an important role in regulating hair growth. MSCs-Exo can promote the proliferation and differentiation of DPCs by regulating the hair growth cycle. In recent years, research on MSCs-Exo has provided a new strategy for hair regeneration. This article reviewed the research on the use of MSCs-Exo for hair regeneration, aiming to offer new insights for the treatment of alopecia.

In the past decades, significant progress has been achived in cartilage regeneration. The traditional techniques for constructing tissue engineering cartilage scaffold mainly include pore agent method (or template method), phase separation method, gas foaming method, freeze-drying method, electrospinning method, etc. Cartilage is heterogeneous, and it is difficult for traditional scaffolds to simulate the high anisotropy of cartilage. Therefore, functional regeneration of cartilage is challenging. With the progress of three-dimensional(3D) printing technology, it is possible to prepare functional bionic scaffolds with fine structure and gradient changes through co-deposition of biomaterials, cells and active biomolecules, so as to achieve functional cartilage regeneration. This article reviewed 3D printing technology of cartilage tissue engineering, and the application of 3D printing technology in cartilage regeneration at different anatomical positions (articular cartilage, auricle cartilage, nasal cartilage). In addition, the importance of preparing bionic constructs with regional structure gradient and regional composition gradient was discussed. 3D bioprinting technology, 4D printing techniques, smart biomaterials brought hope for the construction of bionic tissues and organs.

Objective:To discuss the clinical curative effect of the treatment of bundling bone fragment with figure-of-eight suture through double bone tunnels in the chronic bong mallet finger.Methods:A retrospective analysis was performed on patients with chronic bong mallet fingers who underwent surgery in the Department of Hand and Foot Microsurgery of Nanjing Jiangbei Hospital from May 2021 to February 2023. During the procedure, made into transverse double bone tunnels on the base of the distal phalanx with 0. 8 mm Kirschner wire, bundling bone fragment with figure-of-eight suture through double bone tunnels, then fixed with Kirschner wire elastic compression. Removal of the Kirschner wire 3 weeks after the procedure, the active flexion and extension range of the joints of the affected finger and the corresponding finger were measured at the last follow-up, then the range of motion (ROM) of the distal interphalangeal joint (DIPJ) and total action movement (TAM) of the fingers (affected and healthy finger) were recorded. The curative effects were evaluated according to the TAM system of the American Association of Hand Surgeons, including 4 grades: excellent, good, fair, and poor. SPSS 13. 0 software was used for statistical analysis of the data, and the measurement data conforming to normal distribution were expressed as Mean ± SD. The ROM of DIPJ and TAM of the affected finger were compared with the corresponding healthy finger 6 months after surgery by a paired sample t test. P<0. 05 indicates that the difference is statistically significant. Results:A total of 30 patients (30 digits) were enrolled, including 19 males and 11 females, and the age ranged from 18 to 62 years old, with an average age of 31 years old. The time from injury to operation was 24 to 65 days (mean of 35 days) . According to Wehbe and Schneider classification, there were 8 cases of type Ⅰa, 6 cases of type Ⅰb, 7 cases of type Ⅱa, 5 cases of type Ⅱb, 2 cases of type Ⅲa and 2 cases of type Ⅲb. All incisions healed well, the intraoperative blood loss was minimal, with no infection. All 30 cases were followed up for 6 to 7 months. All fractures were well aligned and healed, malformed fingers were completely corrected, and no needle tunnel infection or needle breakage were observed. At the last follow-up, the differences of the ROM of the DIPJ [ (30. 2±3. 5) °vs. (30. 4±3. 3) °, t=2. 57, P=0. 463] and the TAM [ (235. 3± 3. 6) ° vs. (237. 7± 4. 2) °, t=1. 78, P= 0. 247 ] between the affected and healthy fingers were not statistically significant. Finger function assessment: 27 cases were excellent, and 3 cases were good, and the excellent and good rate was 100%. Conclusion:Satisfactory therapeutic outcome for the treatment of chronic bong mallet finger deformity can be achieved by bundling bone fragment with figure-of-eight suture through double bone tunnels. It is an effective and practical method.

Objective:To learn about physicians’ concepts and commonly employed method in hyaluronic acid injection and provide reference data for the standardization of pain management.Methods:This study was a cross-sectional study. Convenient sampling method was used to distribute questionnaires to cosmetic injectors and patients experienced with hyaluronic acid injections to collect data on their views of pain associated with hyaluronic acid injections. The physician portion was collected offline from June 15 to July 20, 2022, and the patient portion was collected from November 14, 2022, to December 6, 2022, via the Questionnaire Star platform. The physician questionnaire consisted of 17 questions, question types included single choice, multiple choice and essay questions. The patient questionnaire consisted of 6 questions, question types included single choice and multiple choice. Relevant data were analyzed using SPSS 22.0 software for descriptive statistics, and data were presented in the form of cases and percentages (%).Results:Sixty-two physician questionnaires and 123 patient questionnaires were collected. 42 (67.74%) physicians observed from their daily practice that more than 50% of their patients were very concerned about pain during injection; 101 (82.11%) patients scored ≥5 out of 10 for concern about impending pain prior to hyaluronic acid filler injection. At the time of treatment, 48 (77.42%) physicians advised patients to choose a lidocaine-containing hyaluronic acid filler for reasons including a significant reduction in injection pain (53 cases, 85.48%) and patient comfort with the treatment experience (59 cases, 95.16%). 60 (48.78%) patients were willing to choose an anesthesia-containing product at the time of injection, but the price of the anesthesia-containing product influenced the patient’ s choice (55 cases 44.72%) .Conclusions:Pain from cosmetic injectable treatments is an important issue to both physicians and patients. Lidocaine-containing hyaluronic acid is recognized by physicians and patients for its analgesic effect and high safety profile. There is no perfect solution for pain in cosmetic injection treatment, and multidisciplinary collaboration may be needed to solve the problem.

The incidence rate of androgenetic alopecia is increasing year by year and presents a trend of younger age, which puzzles many patients. In recent years, there have been many new treatment methods and ideas for androgenetic alopecia, so the treatment strategies for androgenetic alopecia need to be updated accordingly. In addition, with the development of the hair industry in recent years, a large number of practitioners have flocked to positions related to the diagnosis and treatment of androgenetic alopecia, so proven guidelines are needed for guidance. The guide writing team selected relevant clinical issues, gave recommendations based on a thorough literature review of the latest reports and expert’s evaluation, in the hope of providing a treatment algorithm for androgenetic alopecia.

Objective:To summarize the experience of designing transplanted hair based on the orbital morphology and tissue characteristics for the treatment of eyebrow defects after burns.Methods:A retrospective analysis was conducted on clinical data of the patients with eyebrow defects after burns who treated at Hair Transplantation Center, Plastic Surgery Hospital, Chinese Academy of Medical Sciences between January 2011 and September 2023. The location and appearance of eyebrow were designed according to the orbital morphology and tissue characteristics. The follicles were extracted by incision of scalps strips and follicle unit excision (FUE) on the donor area of the occipital region near the posterior hairline or the posterior ear hairline. Scalps with scars that needed to be removed or had "dog ear" deformities following scalp expansion surgery that needed to be repaired were also be used as donor sites. The follicles were divided as follicle units (FUs) including single hair. The recipient area was punched with syringe needle of 22 or 22 G to subcutaneous superficial layer. Then the hair shaft was clamped with microforceps and the hairs were transplanted to the defective area to restore the appearance of eyebrow. The density, morphology, direction and scars of the donor sites were observed by following-ups.Results:A total of 197 patients with 282 eyebrows were recruited. There were 133 males and 64 females. The average age was 33.7 (9 to 62) years. There were 17 patients with skin graft transplantation in the eyebrow arch, 33 with flap and expanded flap repair, 36 with eyelid skin grafting, 111 with burn scar healing. A total of 51 patients had complete eyebrow defects on both sides, and 34 had partial defects. Sixty-five patients had complete eyebrow defects on single side, and 47 had partial defects. The amount of hair transplantation was from 53 to 600 FUs on 282 eyebrows. Seventy-five patients extracted follicles with incision of scalps strips and 122 with FUE. The patients were followed up for 9 months to 10 years. Folliculitis were found in 17 patients and completely cured by 75% alcohol disinfection. Nine patients with insufficient density underwent hair transplantation for a second time to increase the density of hairs one year later. And the implanted hairs grew well, which were similar to the shape and direction of normal eyebrows. Transplanted hairs of the rest patients grew well. The direction and appearance were satisfied. The scar in the donor site was not obvious.Conclusion:The transplanted hair should be designed primarily based on the orbital morphology and tissue characteristics for the treatment of eyebrow defects after burns. Then the position of the eyebrow and the bilateral symmetry should be considered. The ideal effect of eyebrow reconstruction would depend on the full consideration of the receipt site.

Objective:To investigate the clinical effect of autologous fat transplantation combined with hair transplantation in the treatment of hard and/or thin scalp flat scar after burn.Methods:The clinical data of patients with hard and thin scalp scar after burn admitted to the Department of Plastic Surgery of Peking University Third Hospital from January 2017 to December 2022 were retrospectively analyzed. Fat was extracted from the lower abdomen or outer thigh during the operation, and then injected into the scalp scar after standing for 15 minutes, about 0.8 ml/cm 2 under the hard and/or thin scar area, and 0.2-0.4 ml/cm 2 under the thick and soft scar area. Three months after fat transplantation, hair transplantation was performed in the scar bald area, and the transplant density was 25-35 follicular units (FUs)/cm 2 in the hard and thin scar area, and 30-40 FUs /cm 2 in the thick and soft scar area. The Vancouver scar scale (VSS) was used by two third party plastic surgeons to score the hard and/or thin scar areas of the scalp before and 3 months after scalp fat transplantation. The VSS score was expressed as M ( Q1, Q3), and the preoperative and postoperative data were compared by paired sample Wilcoxon signed rank test. During hair transplantation, the density of implanted hair in the hard and/or thin scar area were recorded. The density of living hair at these sites was measured at the last follow-up, and then the survival rate of hair (living hair density/implant hair density ×100%) was calculated. A third party plastic surgeon evaluated the extent to which scalp scars in the hair transplant area were covered, including completely covered, basically covered, partially covered. Patients’ evaluation with the surgical result was divided into very satisfied, satisfied and dissatisfied. Results:A total of 57 patients with scalp scar after burn were included in this group, including 31 males and 26 females, aged 13-47 years old. The time from scalp scarring to treatment was 8-41 years. The area of scalp scar was 17-120 cm 2, with an average of 63.3 cm 2. The fat injection volume of 57 patients was 13-75 ml. The hair transplantation was performed 3-8 months after a single fat filling procedure. The total amount of hair transplantation was 510-3 120 FUs. The total score of postoperative scar VSS was 4(3, 4), significantly lower than the preoperative score of 7(6, 7) ( W=6.70, P < 0.001). The color, thickness, blood vessel distribution and softness were significantly reduced compared with those before surgery ( P< 0.01). All patients were followed up for 12-18 months (mean, 14 months) after hair transplantation. The survival rate of hair in hard and thin scar area was 68.2% (22.7 FUs/cm 2/33.3 FUs/cm 2) to 89.7% (26.1 FUs/cm 2/29.1 FUs/cm 2), with an average of 81.3%. In 32 patients, scalp scars were completely covered. The scalp scar of 25 patients was basically covered. Twenty-nine patients were very satisfied with the result of the operation, and 28 patients were satisfied. Conclusion:The high survival rate of hair transplantation can be obtained by injecting fat under the hard and/or thin scalp scars before hair transplantation, which is an effective method to repair scalp scars.

Objective:To investigate the effect of laboratory indicators on hair loss in patients with female pattern hair loss (FPHL).Methods:Patients with FPHL who visited the Outpatient Clinic of the Department of Medical Aesthetics in Hangzhou First People’s Hospital from November 2022 to November 2023 were selected as the study group, and healthy women who matched the age of the study group in the physical examination center during the same period were selected as the control group. The general information of the patient was recorded, and was also tested by trichoscopy to rule out other patterns of alopecia. Representative indicators including testosterone, dehydroepiandrosterone sulfate(DHEA-S), thyroid-stimulating hormone, 25-hydroxyvitamin D, and serum ferritin were selected from laboratory tests for further analysis. Otherwise, the proportion of deficiency in vitamin D(<20 ng/ml) was calculated based on 25-hydroxyvitamin D levels (number of deficiency cases/total number of cases in each group×100%). Count data were presented as samples (percentages), and chi-square test was used for comparison between groups. Normally distributed continuous data were presented with Mean±SD, independent samples t-test was used for comparison between groups, M( Q1, Q3) was used for non-normally distributed continuous data, and Wilcoxon rank-sum test was used for comparison between groups. Multivariate logistic regression was used to analyze the influencing factors of FPHL. P<0.05 was statistically significant. Results:A total of 37 patients were selected in both groups. The mean age was (28.8±1.3) years in the study group and (29.6±0.9) years in the control group ( t=0.49, P=0.625). The body mass index was (22.8±0.4) kg/m 2 in the study group, and (23.5±0.3) kg/m 2 in the control group ( t=1.26, P=0.211). The testosterone level was 0.58 (0.49, 0.79) nmol/L in the study group, and 0.54 (0.50, 0.78) nmol/L in the control group( Z=1.42, P=0.157). The level of DHEA-S was 6.21 (5.18, 9.60) μmol/L in the study group, and 6.20 (5.20, 9.34) μmol/L in the control group ( Z=2.75, P=0.006). The level of thyroid-stimulating hormone was 2.56 (1.55, 3.66) mU/L in the study group and 1.49 (1.05, 2.65) mU/L in the control group ( Z=2.51, P=0.012). The level of 25-hydroxyvitamin D was 15.44 (11.80, 21.20) ng/ml in the study group, and the level of 25-hydroxyvitamin D was 20.32 (12.07, 21.20) ng/ml in the control group ( Z=2.30, P=0.021), and the proportion of 25-hydroxyvitamin D deficiency in the study group was 64.9% (24/37), which was higher than that in the control group [40.5% (15/37)] ( χ2=4.39, P=0.036). The serum ferritin level was 64.44 (39.47, 133.45) μg/L in the study group and 67.75 (52.63, 143.83) μg/L in the control group ( Z=0.70, P=0.484). The results of multivariate logistic regression analysis showed that the risk of FPHL was increased by the high level of DHEA-S and thyroid-stimulating hormone, and the low level of 25-hydroxyvitamin D (all P<0.05). Conclusion:Abnormal level of DHEA-S, thyroid-stimulating hormone, and 25-hydroxyvitamin D may be risk factors for FPHL.

Objective:To explore the effect of sleep deprivation on hair growth cycle in mice.Methods:Seventy-two adult C57BL/6J mice were randomly divided into a control group of 36 mice and an experimental group of 36 mice using a lottery method. After hair removal, in the control the group the mice were subjected to routine feeding in a horizontal platform environment for 16 hours per day, while in the experimental group the mice were subjected to sleep deprivation using an improved water platform for 16 hours per day. On the 1st, 9th, and 19th day after the experiment, the skin tissue from the hair removal area of the two groups of mice was taken for HE staining. Then the mouse hair was staged and scored by observing hair follicle morphology under an optical microscope. The cycle and score of the hair was started from the telogen, which was set as 0 points; the anagen Ⅰ to V were set as 1-5 points; the anagen Ⅵ and catagen Ⅰ were set as 6 points; the catagen Ⅱ to Ⅷ were set at 7-13 points. Statistical analysis was conducted by SPSS 26.0. The hair cycle score was expressed as Mean±SD. Student’s t-test was used for comparison between groups at the same time point, and Welch-test was used for comparison of scores at different time points within the group. P<0.05 indicated a statistically significant difference. Results:On the 1st, 9th, and 19th day, the hair cycle scores of the control group were 1.00 ± 0.57, 5.04 ± 0.94, and 9.52 ± 0.87 points, while the hair cycle scores of the experimental group were 0.85 ± 0.62, 2.40 ± 0.50 and 6.08 ± 0.42 points. Inter group comparison showed that the hair cycle scores of the experimental group were lower than those of the control group at all three time points. There was no statistically significant difference on the 1st day ( t=1.03, P=0.307), while the differences were statistically significant on the 9th day ( t=13.38, P<0.001) and the 19th day ( t=16.41, P<0.001). Intragroup comparison showed that there was a statistically significant difference in hair cycle scores between the control group and the experimental group at different time points( P<0.01), and the scores increased over time. Conclusion:Sleep deprivation can cause a lag in the hair growth cycle of mice, but it does not cause a cessation of the hair growth cycle. The degree of lag gradually increases with the number of deprivation days.