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.

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.

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.

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.

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.

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.

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.

Machine learning analysis of online patient questions regarding breast reconstruction.

BACKGROUND: Social media has become a dominant educational resource for breast reconstruction patients. Rather than passively consuming information, patients interact directly with other users and healthcare professionals. While online information for breast reconstruction has been analyzed previously, a robust analysis of patient questions on online forums has not been conducted. In this study, the authors used a machine learning approach to analyze and categorize online patient questions regarding breast reconstruction. METHODS: Realself.com was accessed and questions pertaining to breast reconstruction were extracted. Data collected included the date of question, poster's location, question header, question text, and available tags. Questions were analyzed and categorized by two independent reviewers. RESULTS: 522 preoperative questions were analyzed. Geographic analysis is displayed in Figure 1. Questions were often asked in the pre-mastectomy period (38.3%); however, patients with tissue expanders currently in place made up 28.5%. Questions were often related to reconstructive methods (23.2%), implant selection (19.5%), and tissue expander concerns (16.7%). Questions asked in the post-lumpectomy period were significantly more likely to be related to insurance/cost and reconstructive candidacy (p < 0.01). The "Top 6″ patient questions were determined by machine learning analysis, and the most common of which was "Can I get good results going direct to implant after mastectomy?" CONCLUSIONS: Analysis of online questions provides valuable insights and may help inform our educational approach toward our breast reconstruction patients. Our findings suggest that questions are common throughout the reconstructive process and do not end after the initial consultation. Patients most often want more information on the reconstructive options, implant selection, and the tissue expansion process.

Air Versus Saline in Tissue Expanders: A Systematic Review of the Literature.

BACKGROUND: There has been a greater focus in recent literature proposing air to be a superior medium to saline in tissue expanders. This study aims to review the literature and assess the quality of data on the efficacy and safety of air as an alternative medium to saline in tissue expanders, in the setting of postmastectomy two-stage reconstruction. METHODS: A systematic review regarding air inflation of tissue expanders was conducted using PubMed, Embase, Cochrane Library, and Web of Science. The methods followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Three reviewers separately performed data extraction and comprehensive synthesis. RESULTS: A total of 427 articles were identified in our search query, of which 11 met the inclusion criteria. Three pertained to inflation with room air, and eight pertained to inflation with CO2 using the AeroForm device. They were comparable to decreased overall complication rates in the room air/CO2 cohort compared to saline, although statistical significance was only observed in one of five two-arm studies. Investigating specific complications in the five two-arm studies, significantly lower rates of skin flap necrosis were only observed in two CO2-based studies. Studies rarely discussed other safety profile concerns, such as the impacts of air travel, radiation planning, and air extravasation beyond descriptions of select patients within the cohort. CONCLUSION: There is insufficient evidence to suggest improved outcomes with room air inflation of tissue expanders. Further work is needed to fully characterize the benefits and safety profiles of air insufflation before being adopted into clinical practice.

Comparison of Different Acellular Dermal Matrix in Breast Reconstruction: A Skin-to-Skin Study.

BACKGROUND: Since the early 2000s, acellular dermal matrix has been a popular adjunct to prepectoral breast reconstruction to enhance outcomes. OBJECTIVES: The aim of this study was to investigate the differences in the postoperative course of 2 standard acellular dermal matrix products, AlloDerm SELECT Ready To Use and DermACELL. METHODS: A prospective, patient-blind study of patients undergoing bilateral nipple and/or skin-sparing mastectomies with either tissue expander or silicone implant insertion between 2019 and 2022 were selected for this study. The study design used patients as their own controls between 2 products randomly assigned to the left or right breast. Outcomes between the products included average time for drain removal, infection rate, seroma rate, and incorporation rates. RESULTS: The prospective clinical data of 55 patients (110 breasts) were recorded for 90 days. There were no significant differences between drain removal time, average drain output, or seroma aspiration amount. A higher percentage of seromas was recorded in the breasts with AlloDerm (30.91%) compared with breasts containing DermACELL (14.55%, P < .05), and a statistically significant difference between the incorporation rates of AlloDerm (93.4%) and DermACELL (99.8%, P < .05) was observed. CONCLUSIONS: Irrespective of patient demographic disparities, both products had a 94.55% success rate for reconstruction outcomes. AlloDerm was determined to have a higher incidence of seromas as a postoperative complication and a trend to lower incorporation.

Use of the modified meek technique for the coverage of extensive burn wounds.

INTRODUCTION: Autologous split thickness skin grafting using meshing technique remains the preferred option for the management of deep dermal and full thickness burns. The limited donor site availability seen in patients with extensive burns, however, restricts use of the mesh grafting technique for skin expansion. Meek micrografting was developed to allow for greater expansion, and, therefore, more reliable treatment of extensive burns. This study aimed to present our outcomes using the Meek micrografting technique and identify risk factors for graft failure. METHODS: A retrospective review of patients admitted to our large academic hospital who were treated with the Meek micrografting technique from 2013 to 2022 was conducted. Patient demographics, surgical characteristics and outcomes were reported. Regression analyses were performed to identify factors that influence graft take and reoperation rate. RESULTS: A total of 73 patients with a mean age of 45.7 ± 19.9 years and mean burn size of 60.0 ± 17.8%TBSA, with 45.3 ± 14.9% TBSA being third degree burns, received Meek transplantation. The mean graft take after removal of the pre-folded polyamide gauze at the tenth post-operative day was 75.8 ± 14.7%. Pre-treatment with use of an allograft, longer waiting time between admission and Meek grafting and transplantation over a dermal matrix were identified as positive predictors for graft take, while age was established as a negative predictor. CONCLUSION: By examining the outcomes of the Meek micrografting technique in extensive burn wounds we identified that preconditioning of the wound bed, through allograft or negative pressure wound therapy application, positively correlates with improved outcomes, including higher graft take. At the same time, older age was seen to negatively correlate with graft take. Overall, Meek transplantation displays a favorable safety profile with promising outcomes. Future prospective studies and clinical trials can optimize the procedure and help establish it as the golden standard for extensive and complex burns.

Scalp Closure in Midline Cutis Aplasia-An Absolute Indication for Preoperative Imaging.

The ideal evaluation and treatment of aplasia cutis congenita remains disputed. We present a case of midline scalp cutis aplasia that healed by secondary intention, leaving an area of residual alopecia. There were no clinical indicators of an underlying calvarial defect. Tissue expansion of the scalp was done in preparation for scalp closure. However, on the removal of the expanders and scalp advancement, an unrecognized midline calvarial defect in which a scar tract of herniated dura was found. This resulted in a dural tear, repaired with minimal hemorrhage. However, manipulation of the sagittal sinus resulted in a right subdural hemorrhage followed by cerebral ischemia and a stroke. On the basis of this clinical scenario, we recommend that all cases of midline scalp cutis aplasia undergo preoperative imaging with thin slices of the calvaria before performing scalp advancement-even if the only clinical indication for surgery is scalp alopecia without a palpable skull defect.

Post-mastectomy Breast Reconstruction With Gas vs Saline Tissue Expanders: Does the Fill Type Matter?

The most common reconstruction technique following mastectomy is a 2-stage technique that involves tissue expansion followed by definitive implant-based reconstruction (IBR). Tissue expanders (TEs) have classically used saline for initial fill; however, TEs with an initial gas fill (GTE)-including the CO2-based AeroForm (AirXpanders, San Francisco, CA) TE and TEs initially filled with atmospheric air-have been increasingly used in the past decade. We aimed to compare the outcomes in breast reconstruction for tissue expanders initially filled with saline vs gas. PubMed was queried for studies comparing gas- and saline-filled tissue expanders (STEs) used in IBR. A meta-analysis was performed on major postoperative outcomes and the required expansion and definitive reconstruction time. Eleven studies were selected and included in the analysis. No significant differences existed between tissue expansion with GTEs vs STEs for 11 of the 13 postoperative outcomes investigated. Out of the complications investigated, only the risk of infection/cellulitis/abscess formation was significantly lower in the GTE cohort (odds ratio 0.62; 95% CI, 0.47 to 0.82; P = .0009). The time to definitive reconstruction was also significantly lower in the GTE cohort (mean difference [MD], 45.85 days; 95% CI, -57.80 to -33.90; P < .00001). The total time to full expansion approached significance in the GTE cohort (MD, -20.33 days; 95% CI, -41.71 to 1.04; P = .06). A cost analysis considering TE cost and infection risk determined that GTE use saved a predicted $2055.34 in overall healthcare costs. Surgical outcomes for both fill types were predominantly similar; however, GTEs were associated with a significantly decreased risk of postoperative infection compared to saline-filled TEs. GTEs could also reduce healthcare expenditures and require less time until definitive reconstruction after placement.

Lower Extremity Pediatric Tissue Expansion: A Single Surgeon's 16-Year Experience.

BACKGROUND: Tissue expansion is a well-established approach to soft tissue reconstruction in the pediatric population for lower extremity pathologies. Unfortunately, complication rates range from 19% to 40% in literature, including infection and implant extrusion, leading to delays in reconstruction. These challenges have prompted investigation toward categorizing risk factors for lower extremity tissue expander placement. METHODS: A retrospective study of pediatric patients who underwent lower extremity tissue expander placement by the senior author (R.J.R.) was performed over a 16-year period. Patient charts were reviewed to categorize baseline and operative characteristics. Primary outcome variables were surgical-site infection, expander extrusion, and expander deflation. Univariate and multivariate logistic regressions were performed ( α < 0.05). RESULTS: There were 59 tissue expanders in our cohort. The overall complication rate was 27.1% with a 77.2% successful reconstruction rate. Greater number of expanders placed during 1 operation is associated with 2.5 increased odds of having any complication and is associated with 0.4 decreased odds of having a successful reconstruction. Incisions made in scar tissue for expander placement appear to be associated with a greater than 7 times increased odds of readmission. CONCLUSIONS: Reconstruction of soft tissue pathologies using lower extremity tissue expanders in the pediatric population is an effective yet challenging technique. This study identified that the number of expanders inserted during 1 operation, incisions made over scar tissue, and expanders placed in the anterior thigh were correlated with having a negative impact on reconstructive outcomes. Extra care should be taken with patients who require multiple expanders during 1 operation and with choosing the location and incision of expander placement.

Resurfacing of Sleeve-Like Circumferential Giant Congenital Melanocytic Nevi on the Upper Extremity With Pre-Expanded Pedicled Flap.

As the relative shortage of healthy tissue obviates the option of local soft tissue coverage, reconstruction of circumferential giant congenital melanocytic nevi (GCMN) on the upper extremity remains particularly challenging. Here the authors report a 3-stage procedure involving pre-expanded pedicled flap from the torso for the reconstruction of upper extremity after circumferential GCMN excision in pediatric patients. The giant nevus was completely removed and the size of the excised nevus was 31 × 14.5 cm. The donor site was primarily closed. No major complication was encountered. Reconstruction with expanded pedicled flap achieved satisfactory results, both functionally and cosmetically.

Acellular Dermal Matrix Cover Improves Skin Growth during Tissue Expansion by Affecting Distribution of Mechanical Forces.

BACKGROUND: Biological cover over tissue expander prostheses has been introduced to provide soft-tissue support for tissue expanders during breast reconstruction. However, its impact on mechanically induced skin growth remains unknown. This study investigates the hypothesis that covering the tissue expander with acellular dermal matrix (ADM) affects mechanotransduction without compromising the efficacy of tissue expansion. METHODS: Tissue expansion, with and without use of ADM, was performed on a porcine model. The tissue expanders were inflated twice with 45 mL of saline, and the full-thickness skin biopsy specimens were harvested from expanded and control unexpanded skin 1 week and 8 weeks after the final inflation. Histologic evaluation, immunohistochemistry staining, and gene expression analysis were performed. Skin growth and total deformation were evaluated using isogeometric analysis. RESULTS: The authors' results demonstrate that use of ADM as a biological cover during tissue expansion does not impede mechanotransduction that leads to skin growth and blood vessel formation. Isogeometric analysis revealed similar total deformation and growth of expanded skin with and without a biological cover, confirming that its use does not inhibit mechanically induced skin growth. In addition, the authors found that use of an ADM cover results in more uniform distribution of mechanical forces applied by the tissue expander. CONCLUSIONS: These results suggest that ADM improves mechanically induced skin growth during tissue expansion by facilitating a more uniform distribution of mechanical forces applied by the tissue expander. Therefore, the use of a biological cover has potential to improve outcomes in tissue expansion-based reconstruction.

Tracing the Change and Contribution of Subcutaneous Adipose to Skin Expansion Using a Luciferase-Transgenic Fat Transplantation Model.

BACKGROUND: During skin expansion, subcutaneous adipose tissue undergoes the greatest change. The adipose layer appears to gradually thin or even disappear in long-term expansion. The response and contribution of adipose tissue to skin expansion remain to be elucidated. METHODS: The authors established a novel expansion model by transplanting luciferase-transgenic adipose tissue into the rat dorsum, followed by integrated expansion, to trace the dynamic changes in subcutaneous adipose tissue during expansion and the migration of adipose tissue-derived cells. In vivo luminescent imaging was performed to continuously track the adipose tissue changes. Histologic analysis and immunohistochemical staining evaluated the regeneration and vascularization of the expanded skin. Growth factor expression in expanded skin with or without adipose tissue was determined to evaluate the paracrine effect of adipose tissue. Adipose tissue-derived cells were traced in vitro by anti-luciferase staining, and their fate was determined by costaining for PDGFRα, DLK1, and CD31. RESULTS: In vivo bioimaging showed that cells in adipose tissue were alive during expansion. After expansion, the adipose tissue exhibited fibrotic-like structures, with more DLK1 + preadipocytes. Skin expanded with adipose tissue was significantly thicker than that without adipose tissue, with more blood vessels and cell proliferation. Vascular endothelial growth factor, epidermal growth factor, and basic fibroblast growth factor expression was higher in adipose tissue than in skin, indicating paracrine support from adipose tissue. Luciferase-positive adipose tissue-derived cells were observed in expanded skin, indicating direct participation in skin regeneration. CONCLUSION: Adipose tissue transplantation can effectively promote long-term skin expansion by contributing to vascularization and cell proliferation by means of various mechanisms. CLINICAL RELEVANCE STATEMENT: The authors' findings suggest that it would be better if the expander pocket is dissected over the superficial fascia to preserve a layer of adipose tissue with skin. In addition, their findings support the treatment of fat grafting when expanded skin presents with thinning.