Mechanical force regulates the paracrine functions of ADSCs to assist skin expansion in rats.

BACKGROUND: In the repair of massive tissue defects using expanded large skin flaps, the incidence of complications increases with the size of the expanded area. Currently, stem cell therapy has limitations to solve this problem. We hypothesized that conditioned medium of adipose-derived stem cells (ADSC-CM) collected following mechanical pretreatment can assist skin expansion. METHODS: Rat aortic endothelial cells and fibroblasts were cultured with ADSC-CM collected under 0%, 10%, 12%, and 15% stretching force. Ten-milliliter cylindrical soft tissue expanders were subcutaneously implanted into the backs of 36 Sprague-Dawley rats. The 0% and 10% stretch groups were injected with ADSC-CM collected under 0% and 10% stretching force, respectively, while the control group was not injected. After 3, 7, 14, and 30 days of expansion, expanded skin tissue was harvested for staining and qPCR analyses. RESULTS: Endothelial cells had the best lumen formation and highest migration rate, and fibroblasts secreted the most collagen upon culture with ADSC-CM collected under 10% stretching force. The skin expansion rate was significantly increased in the 10% stretch group. After 7 days of expansion, the number of blood vessels in the expanded area, expression of the angiogenesis-associated proteins vascular endothelial growth factor, basic fibroblast growth factor, and hepatocyte growth factor, and collagen deposition were significantly increased in the 10% stretch group. CONCLUSIONS: The optimal mechanical force upregulates specific paracrine proteins in ADSCs to increase angiogenesis and collagen secretion, and thereby promote skin regeneration and expansion. This study provides a new auxiliary method to expand large skin flaps.

Enhanced Recovery After Surgery (ERAS) With Exparel in Tissue Expander-based Breast Reconstruction Following Mastectomy.

BACKGROUND: Enhanced recovery after surgery (ERAS) pathways have been widely shown to yield positive outcomes, including in plastic surgery. Our group has previously validated ERAS in our deep inferior epigastric perforator flap breast reconstruction population. OBJECTIVES: We evaluated whether the ERAS protocol and addition of liposomal bupivacaine affected patient outcomes at the time of mastectomy and first-stage tissue expander reconstruction. METHODS: All patients treated between July 2021 and May 2022 were reviewed retrospectively. The ERAS protocol was implemented in December 2021. Two patient groups were compared: pre-ERAS and ERAS. The ERAS protocol included use of liposomal bupivacaine in the pectoralis nerve block 1/2 planes. Primary outcomes were observed with postoperative length of stay and hospital narcotic use. RESULTS: Eighty-one patients were analyzed in this cohort. The pre-ERAS group was composed of 41 patients, the ERAS group was composed of 83 patients. Postoperative length of stay was significantly reduced in the ERAS group (1.7 pre-ERAS vs 1.1 ERAS, P = .0004). When looking at morphine equivalents during the hospital stay, the degree of narcotics in the recovery room was relatively similar. Average PACU pain morphine equivalents were 6.1 pre-ERAS vs 7.1 ERAS (P = .406). However, total hospital morphine equivalents were significantly lower in the ERAS group (65.0 pre-ERAS vs 26.2 ERAS, P = <.001). CONCLUSIONS: The introduction of an enhanced recovery after surgery protocol with liposomal bupivacaine pectoralis 1/2 nerve blocks decreased postoperative opioid consumption and hospital length of stay in mastectomy patients undergoing tissue expander-based reconstruction.

A machine learning approach to predict in vivo skin growth.

Since their invention, tissue expanders, which are designed to trigger additional skin growth, have revolutionised many reconstructive surgeries. Currently, however, the sole quantitative method to assess skin growth requires skin excision. Thus, in the context of patient outcomes, a machine learning method which uses non-invasive measurements to predict in vivo skin growth and other skin properties, holds significant value. In this study, the finite element method was used to simulate a typical skin expansion protocol and to perform various simulated wave propagation experiments during the first few days of expansion on 1,000 individual virtual subjects. An artificial neural network trained on this dataset was shown to be capable of predicting the future skin growth at 7 days (avg. R 2 = 0.9353 ) as well as the subject-specific shear modulus ( R 2 = 0.9801 ), growth rate ( R 2 = 0.8649 ), and natural pre-stretch ( R 2 = 0.9783 ) with a very high degree of accuracy. The method presented here has implications for the real-time prediction of patient-specific skin expansion outcomes and could facilitate the development of patient-specific protocols.

Safety Profile Comparison of 2 Smooth Tissue Expander Types: Artoura and CPX4.

INTRODUCTION: With the recent transition to smooth tissue expanders (TEs), functional differences between TE subtypes have not been fully elucidated. This study evaluated the differences in TE characteristics and complications between 2 commonly used Mentor smooth TE models, Artoura and CPX4. METHODS: A retrospective review of patients who received either smooth Mentor Artoura or CPX4 TE from 2012 to 2022 was conducted. Demographic data, perioperative information, pain scores, TE variables, cancer characteristics, and complications were collected. A multivariate analysis was used to evaluate the relationship between TE subtype and complications while controlling for demographic, TE characteristics, radiation, and chemotherapy exposure. RESULTS: During the study period, 62 smooth Artoura TEs and 79 smooth CPX4 TEs were used. Patients who received CPX4 smooth implants tended to be older (51.09 vs 46.18 years old, P = 0.02) and have a higher body mass index (28.66 vs 23.50 kg/m 2 , P < 0.001). There were no differences among patient comorbidities. CPX4 required on average a greater total fill volume (422.23 vs 348.07 mL, P = 0.01) and had a greater drain duration (16.91 vs 14.33 days, P = 0.05). There were no differences in TE plane placement between Artoura and CPX4. Additionally, there were no differences in complication rates, including infection, hematomas, seromas, wound breakdown, TE replacement, and capsular contracture. When controlling for body mass index, diabetes, TE plane placement, acellular dermal matrix use, radiation exposure, and chemotherapy, there was no association between TE subtype and any individual complication. DISCUSSION: Differences in total fill volume and drain duration were significantly different between Mentor Artoura and CPX4 implants, which may influence TE subtype selection. However, Artoura and CPX4 have excellent and equivalent safety profiles with similar complication rates, even when controlling for demographic and TE characteristics.

Autologous Tissue Repair and Total Face Restoration.

Importance: Total face restoration remains a challenge in modern reconstructive surgery. After 17 years of experiments and preliminary clinical studies, a new concept of face prefabrication was developed for face restoration with autologous tissue. Objective: To evaluate the long-term results of face restoration with autologous tissue and report a finalized and standardized approach of face prefabrication. Design, Setting, and Participants: In this single-center long-term retrospective study, 32 patients who underwent total face restoration between 2005 and 2022 were reviewed. These patients underwent total facial reconstruction, which included flap prefabrication, 3-dimensional printing, tissue expansion, and flap transfer with aid of indocyanine green angiography (IGA). The flap first undergoes prefabrication by transferring vascularized fascia under the skin of the selected chest. A tissue expander is then placed under the fascia to create a large, thin, reliable skin flap after expansion. Once completed, the flap is transferred to the face during the second stage of the reconstruction. Intraoperative IGA is performed to guide the design of subsequent openings for facial fissures. Data were analyzed from July to September 2023. Main Outcomes and Measures: Flap healing, reconstructive outcome, and patient recovery were assessed during follow-up. Three questionnaires, including the 36-Item Short Form Health Survey (SF-36), Aesthetic and Functional Status Score of Facial Soft-Tissue Deformities/Defects, and the EuroQoL Health-Related Quality of Life (EQ-5D-5L), were used to evaluate the quality of life and satisfaction with facial aesthetic and functional status. Results: Of 24 included patients, 14 (58%) were male, and the mean (range) age was 32.9 (8-62) years. The mean (range) follow-up was 5.6 (2-12) years. All patients reported a significant improvement in quality of life (SF-36), especially in mean (SD) social functioning (preoperative score, 53.65 [34.51]; postoperative score, 80.73 [19.10]) and emotional stability (preoperative score, 56.67 [25.55]; postoperative score, 71.17 [18.51]). A total of 22 patients (92%) went back to work. Mean (SD) facial aesthetic status (preoperative score, 4.96 [3.26]; postoperative score, 11.52 [3.49]; P < .001) and functional status (preoperative score, 11.09 [3.51]; postoperative score, 15.78 [3.26]; P < .001) also improved. In addition, there was a significant increase in overall satisfaction and self-reported health status (preoperative score, 8.13 [1.52]; postoperative score, 3.58 [2.31]). Conclusions and Relevance: In this study, 5-year follow-up results suggested that this innovative approach to total face restoration offered a safe and valid option for indicated patients, with acceptable reconstructive and cosmetic outcomes.

What did we catch? Predictors of infection after tissue expander-based breast reconstruction in a safety-net system.

BACKGROUND: Infection is a common complication following tissue expander (TE)-based breast reconstruction. Few studies have examined risk factors specifically in the unique populations encountered at safety-net hospitals. The purpose of this study was to identify predictors of TE infection at Harris Health safety-net hospitals, which serve the third most populous county in the United States. METHODS: A retrospective review was performed to evaluate women over the age of 18 years who underwent TE placement at two safety-net hospitals from October 2015 to November 2022. Demographic information, medical history, operative details, and postoperative course were recorded for each individual TE. The primary outcome was TE infection, for which univariate and multivariate analysis was conducted. The secondary outcome was the time to onset of TE infection, for which a Kaplan-Meier analysis was undertaken. RESULTS: There were 279 patients, totaling 372 breasts, meeting the inclusion criteria. The TE infection rate was 23%. Increased body mass index (BMI), diabetes, use of acellular dermal matrix (ADM), and prolonged surgical drain use were all significantly associated with TE infection in univariate and multivariate analysis. Similarly, BMI ≥30 kg/m2, diabetes, and ADM use were also associated with earlier onset of TE infection. CONCLUSIONS: This study demonstrated similar TE infection rates at our safety-net hospitals compared with previously reported literature. To optimize the quality of care for patients in safety-net institutions, these risk factors must be addressed in the context of the unique challenges encountered in these settings.

Prophylactic absorbable antibiotic beads for prepectoral implant-based breast reconstruction: A single institution early experience.

Infection after implant-based breast reconstruction remains challenging, with infection rates up to 24%. Best clinical practice indicates prophylactic oral antibiotics are ineffective at preventing infection. Absorbable antibiotic beads have been routinely used in other surgical subspecialties such as orthopedic and vascular procedures for continuous local antibiotic delivery to the surgical site when implants are placed. Biodegradable calcium sulfate antibiotic beads have been shown to normalize incidence of infection when used prophylactically for a high-risk prepectoral patient population. The purpose of this study is to evaluate the effect of prophylactic biodegradable antibiotic beads when used non-selectively for all prepectoral immediate tissue expander (TE) reconstruction. Patients who underwent mastectomy and immediate prepectoral TE reconstruction on the same day between 2018 and 2024 were reviewed. Patients were divided into two groups: those who received antibiotic beads (Group 1) and those who did not (Group 2). Absorbable calcium-sulfate beads were reconstituted with 1 g vancomycin and 240 mg gentamicin. There were 33 patients (63 TEs) in Group 1 and 330 patients (545 TEs) in Group 2. TE loss was present in 1.5% (1/65 TEs) Group 1 compared to 9.4% (51/545 TEs) in Group 2 (p = 0.032). The mean follow-up time was 178 days (range 93-266 days). Prophylactic biodegradable antibiotic beads used during immediate tissue expander reconstruction decreased implant loss rate. There was one occurrence of SSI in the antibiotic bead group. Antibiotic beads may potentially decrease complications in immediate TE reconstruction when used non-selectively for all patients.

Endoscopic Tissue Expander Implantation in Postburn Reconstruction: A Review of the Literature.

BACKGROUND: Tissue expansion generates new tissue that can be used in postburn reconstruction. Expanders are placed through small incisions, requiring difficult and sometimes blind dissection to prepare an adequate pocket. Recently, the use of endoscopy to assist in expander placement has been described, which may improve intraoperative visualization and allow for a smaller incision. In this review, we summarize the existing literature on endoscopic tissue expander (TE) placement in postburn reconstruction and highlight areas for future research. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were utilized to conduct this review. The following databases were queried for the initial search of relevant articles: PubMed, Embase, Scopus, Cochrane, and Web of Science. The data were assessed qualitatively due to the heterogeneity in reporting between the studies. RESULTS: Our literature query yielded 1023 studies. Sixteen manuscripts underwent full-text review, and 7 met inclusion criteria. All studies demonstrated that the endoscopic approach led to successful tissue expansion. Four articles performed a comparative analysis between the open and endoscopic approach, all of which found a significant reduction in complications like seroma, hematoma formation, and device exposure with endoscopic TE implantation. Two studies demonstrated that the use of endoscopy significantly reduced operative time and length of stay. CONCLUSION: Endoscopy is a safe and effective tool in tissue expansion for postburn reconstruction. Further prospective research should include evaluating the cost-benefit of this approach and long-term outcomes for patients who have undergone endoscopic-assisted TE placement.

One-Stage Deep Inferior Epigastric Perforator Flap Salvage of Infected Tissue Expanders.

BACKGROUND: Tissue expander-based breast reconstruction is associated with high rates of infectious complications, often leading to tissue expander explants and delays in receipt of definitive breast reconstruction and adjuvant therapy. In this study, we describe a single-stage technique where deep inferior epigastric artery perforator (DIEP) flaps are used to salvage actively infected tissue expanders among patients originally planning for free flap reconstruction. METHODS: In this technique, patients with tissue expander infections without systemic illness are maintained on oral antibiotics until the day of their DIEP flap surgery, at which time tissue expander explant is performed in conjunction with aggressive attempt at total capsulectomy and immediate DIEP flap reconstruction. Patients are maintained on 1-2 weeks of oral antibiotics tailored to culture data. Patients undergoing this immediate salvage protocol were retrospectively reviewed, and complications and length of stay were assessed. RESULTS: In a retrospective series, a total of six consecutive patients with culture-proven tissue expander infections underwent tissue expander removal and DIEP flap reconstruction in a single stage and were maintained on 7-14 days of oral antibiotics postoperatively. Within this cohort, no surgical site infections, microvascular complications, partial flap losses, reoperations, or returns to the operating room were noted within a 90-day period. CONCLUSIONS: Among a select cohort of patients, actively infected tissue expanders may be salvaged with free flap breast reconstruction in a single surgery with a low incidence of postoperative complications. Prospective studies are needed to evaluate the influence of this treatment strategy on costs, number of surgeries, and dissatisfaction after staged breast reconstruction complicated by tissue expander infections.

The impact of national health insurance on the cost of auricular reconstruction with skin expansion for microtia in China: A single-center retrospective study based on 1290 surgeries.

BACKGROUND: Congenital microtia presents challenges that encompass physical disabilities and psychosocial distress. It is reported that people with low income have a higher possibility of giving birth to babies with congenital malformations. At the end of June 2023, auricular reconstruction was partially incorporated into national health insurance in our hospital. METHODS: Briefly, 1290 surgeries, including stage-I and stage-II auricular reconstruction with tissue expansion were performed in 2023, involving 779 patients. Patient data, including age, sex, length of stay, residence, and costs, were retrieved from the electronic medical record system. The final cost before and after health insurance coverage, as well as the medical insurance reimbursement ratio in each province and municipality were statistically analyzed. RESULTS: Following insurance coverage, a significant increase in the number of surgeries was observed (514 [39.84%] vs. 776 [60.16%], χ2 = 45.99, p = 0.000), with notable reductions in out-of-pocket costs for unilateral and bilateral stage-I and -II auricular reconstructions ($3915.01 vs. $6645.28, p < 0.05; $11546.80 vs. $5198.08, p < 0.05). Disparities in reimbursement rates across regions were evident, but showed no correlation to the local GDP per capita. There was a positive correlation between the length of stay and inpatient cost. Patient's age was not related to the inpatient cost, but to the length of stay. CONCLUSION: The health insurance coverage for microtia treatment significantly alleviated financial burdens on the patients' family and increased the number of auricular reconstruction surgeries. These findings underscore the critical role of insurance coverage in enhancing healthcare accessibility and affordability for patients with congenital microtia.

Immediate Prepectoral Tissue Expander Breast Reconstruction Without Acellular Dermal Matrix Is Equally Safe Following Skin-Sparing and Nipple-Sparing Mastectomy.

BACKGROUND: Prepectoral breast reconstruction has become increasingly popular over the last decade. There is a paucity of data surrounding the impact of mastectomy type on clinical outcomes when comparing prepectoral immediate breast reconstruction without acellular dermal matrix (ADM) using tissue expansion. The purpose of this study was to compare 90-day reconstructive surgical outcomes in immediate prepectoral tissue expander reconstruction between patients with nipple-sparing mastectomy (NSM) and skin-sparing mastectomy (SSM). METHODS: A retrospective review of patient records was carried out on all patients undergoing NSM or SSM with immediate prepectoral tissue expander reconstruction without ADM, in a single institution, from June 2020 to December 2021. All complications were recorded, categorized, and statistically analyzed for significance. RESULTS: Seventy-nine patients (97 breasts) were studied. The mean age was 51 years old (range, 31-77). Twenty-two patients suffered complications recorded in 22 breasts (22.7%). There was no statistically significant difference in the total complications between the NSM (25.7%) and SSM (21.0%) groups or in the incidence of all major and minor complications. CONCLUSIONS: Breast reconstruction using tissue expanders without ADM has similar reconstructive outcomes in both NSM and SSM. There were no significant differences in complication rates between either groups. Breast reconstruction without ADM can confer institutional cost savings without compromising safety.

Multivariate Analysis of Risk Factors for Complications in Pediatric Tissue Expansion.

BACKGROUND: Tissue expanders represent one of the main surgical options for skin reconstruction in cases of tumors, traumalike burn injury, scar contracture, and alopecia. However, the tissue expander device is also associated with complications such as infection and extrusion. The aim of this study was to analyze risk factors for major complications of use of tissue expanders in pediatric patients using multivariate analysis. METHODS: A retrospective, single-center observational study was performed over 10 years in pediatric patients who were treated with tissue expanders for tumors, nevus, scars, burn reconstruction, and alopecia from April 2012 to March 2022. The primary outcome was overall complications per operation and expander, including infection and extrusion. Ten predictor variables were included as risk factors based on previous studies and as new factors considered important from clinical experience. Univariate and multivariate logistic regression analyses were performed to identify risk factors for major complications such as expander infection or extrusion. RESULTS: The study included 44 patients who underwent 92 operations using 238 tissue expanders. The overall complication rate per expander was 14.3%. Univariate logistic regression analysis identified associations of younger age, number of expanders used per operation, history of infection, and tissue expander locations with a higher complication rate. In multivariate logistic regression analysis, younger age (odds ratio, 1.14; P = 0.043) was associated with a high likelihood of expander complications. CONCLUSIONS: Younger age is an independent risk factor for tissue expander complications in pediatric patients. This factor should be considered in preoperative planning and discussions with the patient's family.

Same day discharge following mastectomy and immediate tissue expander reconstruction: The effect of patient expectations.

BACKGROUND AND PURPOSE: Within, we compare the short-term outcomes of patients receiving same day mastectomy and tissue expander reconstruction for those discharged on postoperative day one versus those discharged immediately following surgery to explore the safety, efficacy, and potential impact on hospital processes. METHODS: This was a retrospective review of patients undergoing mastectomy with immediate TE reconstruction from March 2019 to March 2021. Patients were stratified into two cohorts; observation overnight (OBS), and discharge on same day of surgery (DC). RESULTS: In total, 153 patients underwent 256 mastectomies with immediate TE reconstruction. All patients were female and the mean age was 48 years old. The DC cohort contained 71 patients (125 mastectomies) and there were 82 patients (131 mastectomies) within the OBS cohort. On average the DC cohort had a lower BMI than the OBS group (mean ± SD; DC 26.8 kg/m2 ± 5.3 kg/m2, OBS 28.7 kg/m2 ± 6.1 kg/m2, p = 0.05), the DC cohort had higher rates of adjuvant chemotherapy (DC 40.1%, OBS 23.2%, p = 0.02), and were more likely to undergo bilateral TE reconstruction (DC 76%, OBS 60%, p = 0.03) than the OBS group. No differences were observed between cohorts in complication rates regarding primary or secondary outcomes. CONCLUSION: These findings indicate that it is safe and effective within the immediate 7-day post-operative period to immediately discharge patients undergoing mastectomy with immediate TE reconstruction. Additionally, alteration of patient management practices can have a profound impact on the operational flow within hospitals.

Complications Following Tissue Expander-Based Reconstruction in Pediatric Burn Injuries: A Retrospective Analysis.

BACKGROUND: Tissue expansion has been widely used to reconstruct soft tissue defects following burn injuries in pediatric patients, allowing for satisfactory cosmetic and functional outcomes. Factors impacting the success of tissue expander (TE)-based reconstruction in these patients are poorly understood. Herein, we aim to determine the risk factors for postoperative complications following TE-based reconstruction in pediatric burn patients. METHODS: A retrospective review of pediatric patients who underwent TE placement for burn reconstruction from 2006 to 2019 was performed. Primary outcomes were major complications (TE explantation, extrusion, replacement, flap necrosis, unplanned reoperation, readmission) and wound complications (surgical site infection and wound dehiscence). Descriptive statistics were calculated. The association between primary outcomes, patient demographics, burn characteristics, and TE characteristics was assessed using the chi-squared, Fisher's exact, and Mann-Whitney U tests. RESULTS: Of 28 patients included in the study, the median [interquartile range (IQR)] age was 6.5 (3.3-11.8) years, with a follow-up of 12 (7-32) months. The majority were males [n = 20 (71%)], Black patients [n = 11 (39%)], and experienced burns due to flames [n = 78 (29%)]. Eleven (39%) patients experienced major complications, most commonly TE premature explantation [n = 6 (21%)]. Patients who experienced major complications, compared to those who did not, had a significantly greater median (IQR) % total body surface area (TBSA) [38 (27-52), 10 (5-19), P = 0.002] and number of TEs inserted [2 (2-3), 1 (1-2), P = 0.01]. Ten (36%) patients experienced wound complications, most commonly surgical site infection following TE placement [n = 6 (21%)]. Patients who experienced wound complications, compared to those who did not, had a significantly greater median (IQR) %TBSA [35 (18-45), 19 (13-24), P = 0.02]. CONCLUSION: Pediatric burn injuries involving greater than 30% TBSA and necessitating an increasing number of TEs were associated with worse postoperative complications following TE-based reconstruction.

Direct-to-Implant vs Tissue Expander Placement in Immediate Breast Reconstruction: A Prospective Cohort Study.

BACKGROUND: Direct-to-implant (DTI) breast reconstruction after mastectomy has gained increasing popularity. While concerns over ischemic complications related to tension on the mastectomy flap persist, newer techniques and technologies have enhanced safety of this technique. OBJECTIVES: To compare clinical and patient-reported outcomes of DTI and 2-stage tissue expander (TE) reconstruction. METHODS: A prospective cohort design was utilized to compare the incidence of reconstructive failure among patients undergoing DTI and TE reconstruction by unadjusted bivariate and adjusted multivariable logistic regression analyses. Secondary clinical outcomes of interest included specific complications requiring intervention (infection, seroma, hematoma, mastectomy flap necrosis, incisional dehiscence, device exposure) and time to final drain removal. Patient-reported outcomes on BREAST-Q were also compared. RESULTS: A total of 134 patients (257 breasts) underwent DTI reconstruction and 222 patients (405 breasts) received TEs. DTI patients were significantly younger with lower BMIs; less diabetes, hypertension, and smoking; and smaller breast sizes; they also underwent more nipple-sparing mastectomies with prepectoral reconstructions. Rates of any complication (18% DTI vs 24% TE, P = .047), reconstructive failure (5.1% vs 12%, P = .004), and seroma (3.9% vs 11%, P < .001) were significantly lower in the DTI cohort on unadjusted analyses; however, there were no significant differences on adjusted regressions. Patient-reported satisfaction with breasts, psychosocial well-being, and sexual well-being were more substantively improved with DTI reconstruction. CONCLUSIONS: Prepectoral DTI reconstruction is a viable option for postmastectomy reconstruction in carefully selected patients, with no significant increase in reconstructive failure or other complications.

Total Face Reconstruction with Flap Prefabrication and Soft-Tissue Expansion Techniques.

SUMMARY: Total facial deformities always lead to psychological and functional consequences, making plastic and reconstructive surgery a great challenge. The skin of the anterior chest area is matched in thickness, texture, and color to the head and face. The purpose of this article was to discuss and evaluate reconstructive surgeons' experiences with obtaining a monoblock flap from the anterior thoracic area for entire face reconstruction using flap prefabrication, soft-tissue expansion, and facial plastic surgery following skin flap transplantation. Two patients underwent prefabricated expanded anterior thoracic flap reconstructions for total facial deformities; data collection included face defect size, flap type, the shape of the expander, expansion time, and complications. All the face flaps that were transplanted survived without major complications. It is concluded that using a prefabricated expanded flap to reconstruct an entire facial soft-tissue defect can provide a high degree of matching, a wide enough covering area, and a thin enough skin thickness to cover the face. Autologous flap grafting is easy to implement and has a high application value.

Towards developing a matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) compatible tissue expansion protocol.

Mass spectrometry imaging (MSI) visualizes spatial distribution of molecules in a biological tissue. However, compared with traditional microscopy-based imaging, conventional MSI is limited to its spatial resolution, resulting in difficulties in identifying detailed tissue morphological characters, such as lesion boundary or nanoscale structures. On the other hand, expansion microscopy, a tissue expansion method widely used in optical imaging to improve morphological details, has great potential to solve insufficient spatial resolution in mass spectrometry imaging (MSI). However, expansion microscopy was not originally designed for MSI, resulting in problems while combining expansion microscopy and MSI such as expanded sample fragility, vacuum stability and molecule loss during sample preparation. In this research we developed a MALDI MSI compatible expansion protocol by adjusting sample preparation methods during tissue expansion, successfully combining expansion microscopy with MSI. After tissue expansion the expanded sample can be readily applied to MALDI MSI sample preparation and further data acquisition. The MALDI MSI compatible expansion protocol has great potential to be widely applied in MALDI MSI sample preparation to facilitate improvement of MSI spatial resolution.

Prediction model for haematoma after tissue expander placement: A retrospective cohort study of 7080 cases over 20 years.

Haematoma is an early complication of tissue expander placement and can lead to infection, capsule contracture and various complications, hindering successful reconstruction. However, no scientific models can accurately predict the risk of haematoma following tissue expansion. Therefore, this study aimed to develop and validate a prediction model for haematoma following tissue expander placement. The medical records of patients who underwent expander placement between 2001 and 2021 were obtained from the clinical database of the Department of Plastic Surgery at the Xijing Hospital. A total of 4579 consecutive patients with 7080 expanders and 179 expanded pocket haematomas were analysed. Multivariate logistic regression analysis identified adult age (P = 0.006), male sex (P < 0.001), scar reconstruction (P = 0.019), perioperative hypertension (P < 0.001), face and neck location (P = 0.002) and activated partial thromboplastin time above the normal range (P < 0.001) as risk factors for haematoma. Therefore, these were included in the prediction model, and a nomogram was constructed. The discrimination of the nomogram was robust (area under the curve: 0.78; 95% confidence interval: 0.72-0.83). Further, the prediction model had a strong fit (Hosmer-Lemeshow test, P = 0.066) and maintained similar discrimination after considering performance optimism (bootstrapped area under the curve: 0.79; 95% confidence interval: 0.73-0.84). This clinical prediction model was created using a generalisable dataset and can be utilised to obtain valid haematoma predictions after expander placement, assisting surgeons in implementing preventive measures or interventions to reduce the occurrence of haematoma.