Use of Tranexamic Acid in Gender-Affirming Mastectomy Reduces Rates of Postoperative Hematoma and Seroma.

BACKGROUND: The established safety and efficacy of tranexamic acid (TXA) in minimizing perioperative blood loss has led to increased interest within plastic surgery. Prior studies demonstrate decreased edema, ecchymosis, and reduced rates of postoperative collections with administration of TXA, however its use has not been reported in gender-affirming mastectomy. This represents the first study to evaluate the impact of TXA on postoperative outcomes in patients undergoing gender-affirming mastectomy. METHODS: A single-center cohort study was performed analyzing all consecutive patients undergoing top surgery with the senior author between February 2017 and October 2022. Beginning in June 2021, all patients received 1000 mg intravenous TXA prior to incision and 1000 mg at the conclusion of the procedure. Patients were stratified according to intraoperative administration of TXA, with demographics, surgical characteristics, and postoperative outcomes compared between groups. RESULTS: A total of 851 patients underwent gender-affirming mastectomy. Of these, 646 cases were performed without TXA, while 205 patients received intravenous TXA intraoperatively as above. Patients who received TXA had significantly lower rates of seroma (20.5% vs. 33.0%; p<0.001), and hematoma (0.5% vs. 5.7%; p=0.002). There was no difference in rates of surgical site infection (p=0.74), and use of TXA was not associated with increased rates of venous thromboembolism (p=0.42). CONCLUSIONS: Intraoperative administration of TXA in patients undergoing top surgery may safely reduce the risk of postoperative seroma and hematoma without increased risk of thromboembolic events. Additional data collection and prospective studies are warranted to corroborate these findings.

Re-cognizing the new self: The neurocognitive plasticity of self-processing following facial transplantation.

The face is a defining feature of our individuality, crucial for our social interactions. But what happens when the face connected to the self is radically altered or replaced? We address the plasticity of self-face recognition in the context of facial transplantation. While the acquisition of a new face following facial transplantation is a medical fact, the experience of a new identity is an unexplored psychological outcome. We traced the changes in self-face recognition before and after facial transplantation to understand if and how the transplanted face gradually comes to be perceived and recognized as the recipient's own new face. Neurobehavioral evidence documents a strong representation of the pre-injury appearance pre-operatively, while following the transplantation, the recipient incorporates the new face into his self-identity. The acquisition of this new facial identity is supported by neural activity in medial frontal regions that are considered to integrate psychological and perceptual aspects of the self.

Hyperbaric Oxygen Therapy for Threatened Nipple-Sparing Mastectomy Flaps: An Adjunct for Flap Salvage.

BACKGROUND: Nipple-sparing mastectomy (NSM) is emerging as the standard of care for treatment of breast cancer because of its oncologic safety and superior aesthetic outcomes. However, ischemia or necrosis of the skin flap and/or nipple-areola complex remain frequent complications. Hyperbaric oxygen therapy (HBOT) has emerged as a potential adjunct for flap salvage, although it is not currently a widely accepted practice. Here we review our institution's experience using a protocol of HBOT in patients with signs of flap ischemia or necrosis after NSM. METHODS: Retrospective review identified all patients treated with HBOT at our institution's hyperbaric and wound care center because of signs of ischemia after NSM. Treatment parameters consisted of 90-minute dives at 2.0 atmosphere once or twice daily. Patients unable to tolerate dives were considered a treatment failure, whereas those lost to follow-up were excluded from analysis. Patient demographics, surgical characteristics, and treatment indications were recorded. Primary outcomes assessed were flap salvage (no operative revision), need for revision procedures, and treatment complications. RESULTS: A total of 17 patients and 25 breasts met the inclusion criteria. The mean ± SD time to initiation of HBOT was 9.47 ± 12.7 days. The mean ± SD age was 46.7 ± 10.4 years, and mean ± SD follow-up time was 36.5 ± 25.6 days. Indications for NSM included invasive cancer (41.2%), carcinoma in situ (29.4%), and breast cancer prophylaxis (29.4%). Initial reconstruction included tissue-expander placement (47.1%), autologous reconstruction with deep inferior epigastric flaps (29.4%), and direct-to-implant reconstruction (23.5%). Hyperbaric oxygen therapy indications included ischemia or venous congestion for 15 breasts (60.0%) and partial thickness necrosis for 10 breasts (40.0%). Flap salvage was achieved in 22 of 25 breasts (88.0%). Reoperation was required for 3 breasts (12.0%). Hyperbaric oxygen therapy-related complications were observed in 4 patients (23.5%), which included 3 patients with mild ear pain and 1 patient with severe sinus pressure leading to treatment abortion. CONCLUSIONS: Nipple-sparing mastectomy is an invaluable tool for breast and plastic surgeons to achieve oncologic and cosmetic goals. However, ischemia or necrosis of the nipple-areola complex or mastectomy skin flap remains frequent complications. Hyperbaric oxygen therapy has emerged as a possible intervention for threatened flaps. Our results demonstrate the utility of HBOT in this population to achieve excellent NSM flap salvage rates.

Perioperative Hormone Management in Gender-Affirming Mastectomy: Is Stopping Testosterone before Top Surgery Really Necessary?

BACKGROUND: Gender-affirming mastectomy, or "top surgery," has become one of the most frequently performed procedures for transgender and nonbinary patients. However, management of perioperative testosterone therapy remains controversial. Despite a lack of supporting evidence, many surgeons require cessation of testosterone before top surgery. This is the first study to compare complication rates in patients undergoing gender-affirming mastectomy with and without discontinuation of perioperative testosterone. METHODS: This retrospective review included patients undergoing top surgery by the senior author between 2017 and 2020. Reflecting a change in the senior author's practice, before May of 2019, all patients were required to discontinue testosterone before surgery; all patients treated after this point continued their testosterone regimens throughout the perioperative period. Patients were stratified according to testosterone regimen and perioperative hormone management, with demographic characteristics and postoperative outcomes compared among groups. RESULTS: A total of 490 patients undergoing gender-affirming mastectomy during the study period were included. Testosterone was held perioperatively in 175 patients and continued in 211 patients; 104 patients never received testosterone therapy. Demographic characteristics were similar among groups and there was no difference in rates of hematoma (2.9% versus 2.8% versus 2.9%, respectively; P = 0.99), seroma (1.1% versus 0% versus 1%, respectively; P = 0.31), venous thromboembolism (0% versus 0.5% versus 0%, respectively; P = 0.99), or overall complications (6.9% versus 4.3% versus 5.8%, respectively; P = 0.54). CONCLUSIONS: Our results demonstrate no difference in postoperative complication rates among groups. Whereas further investigation is warranted, our data suggest that routine cessation of testosterone in the perioperative period is not necessary for patients undergoing gender-affirming mastectomy. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Gender-affirming Mastectomy: Comparison of Periareolar and Double Incision Patterns.

Background: Gender-affirming mastectomy has become one of the most frequently performed procedures for transgender and nonbinary patients. Although there are a variety of potential surgical approaches available, the impact of technique on outcomes remains unclear. Here we present our experience performing periareolar and double incision mastectomies, with a focus on comparing patient demographics, preoperative risk factors, and surgical outcomes and complication rates between techniques. Methods: Retrospective review identified patients undergoing gender-affirming mastectomy by the senior author between 2017 and 2020. Patients were stratified according to surgical technique, with demographics and postoperative outcomes compared between groups. Results: In total, 490 patients underwent gender-affirming mastectomy during the study period. An estimated 96 patients underwent periareolar mastectomy, whereas 390 underwent double incision mastectomy. Demographics were similar between groups, and there were no differences in rates of hematoma (3.1% versus 5.6%, respectively; P = 0.90), seroma (33.3% versus 36.4%; P = 0.52), or revision procedures (14.6% versus 15.8% P = 0.84) based on technique. Conclusions: Our results demonstrate no difference in the rates of postoperative complications or revision procedures based on surgical technique. These results also suggest that with an experienced surgeon and proper patient selection, both techniques of gender-affirming mastectomy can be performed safely and with comparable outcomes.

Gender-affirming Phalloplasty: A Postoperative Protocol for Success.

Increased access to care and insurance coverage has led to an increase in gender-affirming surgeries performed in the United States. Gender-affirming phalloplasty has a variety of donor sites and surgical techniques including both pedicled and free flaps. Although surgical techniques and patient outcomes are well-described, no reports in the literature specifically discuss postoperative management, which plays a crucial role in the success of these operations. Here, we present a postoperative protocol based on our institution's experience with gender-affirming phalloplasty with the hope it will serve as a standardized, reproducible reference for centers looking to offer these procedures. Methods: Patients undergoing gender-affirming phalloplasty at our institution followed a standardized protocol from the preoperative stage through phases of postoperative recovery. Medication, laboratory, physical and occupational therapy, flap monitoring, and dressing change guidelines were extracted and compiled into a single resource detailing the postoperative protocol in full. Results: Our institution's standardized postoperative protocol for gender-affirming phalloplasty is detailed, focusing on flap monitoring, mobilization and activity, medications, and postoperative dressing care. One hundred thirty first-stage phalloplasty procedures were performed between May 2017 and December 2021, with two patients (1.5%) experiencing partial necrosis and one incidence (0.8%) of total flap loss. Conclusions: For optimal and safe surgical outcomes, the surgical and extended care teams need to understand flap monitoring as well as specific postoperative protocols. A systematic approach focusing on flap monitoring, mobilization and activity, medications, and postoperative dressing care decreases errors, accelerates recovery, shortens length of stay, and instills confidence in the patient.

Gender-affirming Mastectomy with Concurrent Oncologic Mastectomy.

BACKGROUND: Transmasculine individuals may not have undergone gender-affirming mastectomy and retain natal breast tissue. Our center offers simultaneous oncologic mastectomy with gender-affirming reconstruction to patients who are diagnosed with breast cancer. This study is the first reported series of concurrent gender-affirming and oncologic mastectomies. METHODS: A retrospective chart review of all patients undergoing gender-affirming mastectomy at a single institution from February 2017 to October 2021 was performed. Patients were included who had breast cancer diagnoses or pathologic lesions preoperatively. Demographic factors, comorbidities, surgical details, and oncologic history were collected. Both plastic surgery and breast surgery were present for the gender-affirming oncologic mastectomies. RESULTS: Five patients were identified who presented for gender-affirming mastectomy in the context of breast pathologies. Average patient age was 50.2 ± 14.8 years, and no patients used testosterone at any time. Two (40%) patients had a prior breast surgery that included a breast reduction in one patient and breast conserving lumpectomies in another. Sentinel lymph node biopsies were performed in all patients. Only one patient had a positive sentinel lymph node and was subsequently referred for postoperative radiation and chemotherapy. No oncologic recurrence has been detected with 20.6 and 10.0 months of mean and median follow-up. CONCLUSIONS: When performed in a multidisciplinary and collaborative setting with breast surgeons and plastic surgeons, oncologic mastectomy can be performed safely while concurrently offering patients an aesthetic gender-affirming reconstructive outcome.

Facial Transplantation: Principles and Evolving Concepts.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Appreciate the evolution and increasing complexity of transplanted facial allografts over the past two decades. 2. Discuss indications and contraindications for facial transplantation, and donor and recipient selection criteria and considerations. 3. Discuss logistical, immunologic, and cost considerations in facial transplantation, in addition to emerging technologies used. 4. Understand surgical approaches and anatomical and technical nuances of the procedure. 5. Describe aesthetic, functional, and psychosocial outcomes of facial transplantation reported to date. SUMMARY: This CME article highlights principles and evolving concepts in facial transplantation. The field has witnessed significant advances over the past two decades, with more than 40 face transplants reported to date. The procedure now occupies the highest rung on the reconstructive ladder for patients with extensive facial disfigurement who are not amenable to autologous reconstructive approaches, in pursuit of optimal functional and aesthetic outcomes. Indications, contraindications, and donor and recipient considerations for the procedure are discussed. The authors also review logistical, immunologic, and cost considerations of facial transplantation. Surgical approaches to allograft procurement and transplantation, in addition to technical and anatomical nuances of the procedure, are provided. Finally, the authors review aesthetic, functional, and psychosocial outcomes that have been reported to date.

Hepatic Artery Microvascular Anastomosis in Liver Transplantation: A Systematic Review of the Literature.

BACKGROUND: The operating microscope is used in many centers for microvascular hepatic arterial reconstruction in living as well as deceased donor liver transplantation in adult and pediatric recipients. To date, a systematic review of the literature examining this topic is lacking. METHODS: This systematic review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Three different electronic databases (PubMed, Embase OVID, and Cochrane CENTRAL) were queried. RESULTS: A total of 34 studies were included. The rate of hepatic artery thrombosis (HAT) in noncomparative studies (28) ranged from 0% to 10%, with 8 studies reporting patient deaths resulting from HAT. Within comparative studies, the rate of HAT in patients who underwent arterial reconstruction using the operating microscope ranged from 0% to 5.3%, whereas the rate of HAT in patients who underwent arterial reconstruction using loupe magnification ranged from 0% up to 28.6%, and 2 studies reported patient deaths resulting from HAT. Two comparative studies did not find statistically significant differences between the 2 groups. CONCLUSIONS: Our comprehensive systematic review of the literature seems to suggest that overall, rates of HAT may be lower when the operating microscope is used for hepatic arterial reconstruction in liver transplantation. However, matched comparisons are lacking and surgical teams need to be mindful of the learning curve associated with the use of the operating microscope as compared with loupe magnification, as well as the logistical and time constraints associated with setup of the operating microscope.

A Comparison of Immunosuppression Regimens in Hand, Face, and Kidney Transplantation.

BACKGROUND: Authors have speculated that vascularized composite allotransplantation (VCA) recipients may require greater maintenance immunosuppression than solid organ transplant (SOT) recipients due to the higher antigenicity of skin. However, detailed comparisons of VCA and SOT immunosuppression regimens have been limited. METHODS: Hand and face VCA recipient immunosuppression data were collected through a systematic literature review. Kidney recipient data were obtained through a retrospective chart review of the authors' institution. Prednisone and mycophenolate mofetil (MMF) doses were compared between VCA and kidney recipients at predefined follow-up intervals (<1, 1-5, and >5 y). Tacrolimus target trough levels (TTTL) were compared at follow-up intervals of 1-5 and >5 y, and stratified into our institution's kidney transplant risk-based target ranges (4-6 ng/mL, 6-8 ng/mL) or higher (>8 ng/mL). RESULTS: Immunosuppression data were available for 57 VCA and 98 kidney recipients. There were no significant differences in prednisone doses between groups at all follow-up intervals. VCA recipient mean MMF dose was significantly greater at <1-y (1.71 ± 0.58 versus 1.16 ± 0.55 gm/d; P = 0.01). For VCA recipients, there was a significant difference (P = 0.02) in TTTL distribution over the three predefined therapeutic ranges (4-6 ng/mL, 6-8 ng/mL, and >8 ng/mL) between 1 and 5 y (24.0%, 20.0%, 56.0%, respectively) and >5 y (28.6%, 42.9%, 28.6%). CONCLUSIONS: At longer follow-up, VCA and kidney recipients receive comparable MMF/prednisone doses, and most VCA recipients are treated with TTTL similar to kidney recipients. Further research may improve our understanding of VCA's complex risk/benefit ratio, and enhance informed consent.

Anesthetic Considerations in Facial Transplantation: Experience at NYU Langone Health and Systematic Review.

Anesthetic considerations are integral to the success of facial transplantation (FT), yet limited evidence exists to guide quality improvement. This study presents an institutional anesthesia protocol, defines reported anesthetic considerations, and provides a comprehensive update to inform future directions of the field. METHODS: An institutional "FT Anesthesia Protocol" was developed and applied to 2 face transplants. A systematic review of 3 databases captured FTs in the peer-reviewed literature up to February 2020. Two reviewers independently screened titles and abstracts to include all clinical articles with FT recipient and/or donor-specific preoperative, intraoperative, and relevant postoperative anesthetic variables. Data charting guided a narrative synthesis, and quantitative synthesis reported variables as median (range). RESULTS: Our institutional experience emphasizes the importance of on-site rehearsals, anticipation of patient-specific anesthetic and resuscitative requirements, and long-term pain management. Systematic search identified 1092 unique records, and 129 met inclusion criteria. Reports of 37 FTs in the literature informed the following anesthetic axes: donor pre- and intraoperative management during facial allograft procurement, recipient perioperative care, immunotherapy, antimicrobial prophylaxis, and pain management. Quantitative synthesis of 30 articles showed a median operative time of 18 hours (range, 9-28) and fluid replacement with 13 L (5-18) of crystalloids, 13 units (0-66) of packed red blood cells, 10 units (0-63) of fresh frozen plasma, and 1 unit (0-9) of platelets. CONCLUSIONS: Anesthetic considerations in FT span the continuum of care. Future efforts should guide standard reporting to establish evidence-based strategies that promote quality improvement and patient safety.

Communication Efficiency in a Face Transplant Recipient: Determinants and Therapeutic Implications.

We longitudinally assessed speech intelligibility (percent words correct/pwc), communication efficiency (intelligible words per minute/iwpm), temporal control markers (speech and pause coefficients of variation), and formant frequencies associated with lip motion in a 41-year-old face transplant recipient. Pwc and iwpm at 13 months post-transplantation were both higher than preoperative values. Multivariate regression demonstrated that temporal markers and all formant frequencies associated with lip motion were significant predictors (P < 0.05) of communication efficiency, highlighting the interplay of these variables in generating intelligible and effective speech. These findings can guide us in developing personalized rehabilitative approaches in face transplant recipients for optimal speech outcomes.

Does Laterality of Lower Extremity Donor Site Affect Outcomes in Microvascular Soft Tissue Lower Extremity Reconstruction?

BACKGROUND: There are many different variables to consider in lower extremity microvascular soft tissue reconstruction including flap choice. Our aim is to objectively evaluate recipient complications related to lower extremity donor flap laterality. METHODS: A total of 77 lower extremity soft tissue reconstructions utilizing microvascular free tissue transfers for Gustilo type III between 1979 and 2016 were collected. We compared complication rates between ipsilateral and contralateral donor sites relative to the injured leg. The following parameters were analyzed: overall complications, total flap failure, partial flap failure, major complications, operative takebacks, and salvage rates. RESULTS: In this study, 25 ipsilateral reconstructions were performed, while 52 cases utilized the contralateral leg. Overall complication rates were higher in the ipsilateral group (40.0%) compared with the contralateral side (23.1%) but were not statistically significant (p = 0.12). The ipsilateral group was four times as likely to experience vascular compromise (24.0 vs. 5.8%; p = 0.05). However, there were no significant differences in complications, flap failures or flap survival. Mean operative time was significantly greater in the same side group as compared with the contralateral group (11.3 vs. 7.5 hours; p = 0.006). CONCLUSION: Although there is a higher risk of anastomotic thrombosis, particularly venous thrombosis, associated with ipsilateral donor-site group, there were no significant differences in complications or flap survival. Flaps can be harvested from a traumatized leg with acceptable complication rates while avoiding the morbidity of operating on an uninjured limb.

Levels of Evidence in Plastic Surgery Research: A 10-Year Bibliometric Analysis of 18,889 Publications From 4 Major Journals.

BACKGROUND: Improving the quality of research published in plastic surgery literature has been recognized as a difficult and time-intensive process. Despite significant progress over the last decade, leaders in the field continue to advocate for higher-quality studies to better inform clinical practice. OBJECTIVES: The aim of this study was to evaluate and analyze trends in the levels of evidence (LOEs) of the plastic surgery literature over the last decade in 4 major journals. METHODS: After systematic review of all articles published between 2008 and 2017 in Plastic and Reconstructive Surgery, Annals of Plastic Surgery, Journal of Plastic, Reconstructive, and Aesthetic Surgery, and Aesthetic Surgery Journal (ASJ), included articles were assigned an LOE and classified according to study design and category. RESULTS: In total, 8211 articles were included. Case series and reports represented 36.1% and 13.6% of studies, respectively. Additionally, 27.2% were retrospective cohort studies, 8.2% prospective cohort studies, 3.9% systematic reviews, and 2.9% randomized controlled trials (RCTs). Overall, the percentage of Level I/II studies has increased from 10.9% in 2008 to 17.3% in 2017. ASJ published the greatest proportion of Level I/II studies (23.2%) and RCTs (5.1%) of all the journals. There were significant differences in the distribution of Level I/II studies by journal (P < 0.001) and category (P < 0.001). CONCLUSIONS: Over the past decade, plastic surgery journals have published higher-quality research and a significantly greater proportion of Level I and II studies. The field must continue to strive for robust study designs, while also recognizing the importance of lower-LOE research.

Total Eyelid Transplantation in a Face Transplant: Analysis of Postoperative Periorbital Function.

BACKGROUND: Prolonged impairment of protective ocular functions can compromise vision and lead to blindness if uncorrected. Several facial transplants have incorporated periorbital structures with variable eyelid preservation, but objective assessment of post-transplant periorbital function has been limited. MATERIALS AND METHODS: Kinematic data were collected from a full-face recipient that included the fist total eyelid transplantation at 5 separate pre-transplant (PRE) and post-transplant time points (T1-T4). Using optical facial tracking, eyelid movements were tracked during involuntary blinking and compared with controls. RESULTS: There was significant improvement in right eye aperture from PRE to T1 (ß = 5.54, P < 0.001), with no change between T1 and T4. Aperture fluctuated in the left eye, with a temporary decrease between T2 and T3 corresponding with revision brow lift (ß = -4.57, P < 0.001). Although improved from the pre-transplantation, right and left eye apertures remained significantly smaller than controls at T1 and T4 (P < 0.001). Similarly, spatial coupling increased from PRE to T1 (ß = 0.63, P < 0.001) and remained high at T4, albeit significantly less than controls (P < 0.001). Temporal coupling improved from PRE to T2 (ß = 2.29, P < 0.02) and was sustained at subsequent time points, with no difference relative to controls at T4. Considerable improvement was observed on clinical examination, with full functional status. CONCLUSIONS: Application of a novel method for assessing functional eyelid recovery using facial tracking technology to the first total eyelid transplantation in the setting of a full facial transplant shows clear functional improvement after transplantation and suggests revisions can be performed safely to optimize aesthetic outcomes without permanent negative functional impact.

Knowledge and Skills Acquisition by Plastic Surgery Residents through Digital Simulation Training: A Prospective, Randomized, Blinded Trial.

BACKGROUND: Simulation is a standard component of residency training in many surgical subspecialties, yet its impact on knowledge and skills acquisition in plastic surgery training remains poorly defined. The authors evaluated the potential benefits of simulation-based cleft surgery learning in plastic surgery resident education through a prospective, randomized, blinded trial. METHODS: Thirteen plastic surgery residents were randomized to a digital simulator or textbook demonstrating unilateral cleft lip repair. The following parameters were evaluated before and after randomization: knowledge of surgical steps, procedural confidence, markings performance on a three-dimensional stone model, and surgical performance using a hands-on/high-fidelity three-dimensional haptic model. Participant satisfaction with either educational tool was also assessed. Two expert reviewers blindly graded markings and surgical performance. Intraclass correlation coefficients were calculated. Wilcoxon signed rank and Mann-Whitney U tests were used. RESULTS: Interrater reliability was strong for preintervention and postintervention grading of markings [preintervention intraclass correlation coefficient, 0.97 (p < 0.001); postintervention intraclass correlation coefficient, 0.96 (p < 0.001)] and surgical [preintervention intraclass correlation coefficient, 0.83 (p = 0.002); postintervention intraclass correlation coefficient, 0.81 (p = 0.004)] performance. Postintervention surgical knowledge (40.3 ± 4.4 versus 33.5 ± 3.7; p = 0.03), procedural confidence (24.0 ± 7.0 versus 14.7 ± 2.3; p = 0.03), markings performance (8.0 ± 2.5 versus 2.9 ± 3.1; p = 0.03), and surgical performance (12.3 ± 2.5 versus 8.2 ± 2.3; p = 0.04) significantly improved in the digital simulation group compared with before intervention, but not in the textbook group. All participants were more satisfied with the digital simulator as an educational tool (27.7 ± 2.5 versus 14.4 ± 4.4; p < 0.001). CONCLUSION: The authors present evidence suggesting that digital cognitive simulators lead to significant improvement in surgical knowledge, procedural confidence, markings performance, and surgical performance.

Noninvasive Monitoring of Allograft Rejection Using a Novel Epidermal Sampling Technique.

Despite promising short- and long-term results to date in vascularized composite allotransplantation (VCA), acute rejection remains the most common major complication in recipients. Currently, diagnosis of acute rejection relies on clinical inspection correlated with histopathological analysis. However, disagreement exists regarding the value of full-thickness skin and mucosal biopsies and histopathology remains semiquantitative, subject to sampling bias, and prone to intra- and inter-observer variabilities. Additionally, biopsies may cause infection, scarring, and/or potentially incite rejection through immune activation after injury. Noninvasive methods to diagnose rejection represent a critical unmet need for the emerging field of VCA. Here, we propose a novel technique utilizing skin stripping of the epidermis and subsequent molecular analysis to detect known markers of acute rejection. Using a small animal VCA model, we sought to validate our epidermal sampling technique as a noninvasive diagnostic test for acute rejection.