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Main Response Topics Introduction Open display and public evaluation Publicity versus patient privacy Facial tissue donation Validity of Louisville Instrument for Risk Acceptance Patients' understanding of risk Face versus hand transplantation Rejection rates/risks Patient compliance Exit strategy Functional recovery Societietal implications Psychological implications Conclusion: Uncertainty likely to persist [ABSTRACT FROM AUTHOR]

Purpose: Microvascular surgery requires highly specialized and individualized training; most surgical residency training programs are not equipped with microsurgery teaching expertise and/or facilities. The aim of this manuscript was to describe the methodology and clinical effectiveness of an international microsurgery course, currently taught year-round in eight countries., Methods: In the 5-day microsurgery course trainees perform arterial and venous end-to-end, end-to-side, one-way-up, and continuous suture anastomoses and vein graft techniques in live animals, supported by video demonstrations and hands-on guidance by a full-time instructor. To assess and monitor each trainee's progress, the course's effectiveness is evaluated using "in-course" evaluations, and participant satisfaction and clinical relevance are assessed using a "post-course" survey., Results: Between 2007 and 2017, more than 600 trainees participated in the microsurgery course. "In-course" evaluations of patency rates revealed 80.3% (arterial) and 39% (venous) performed in end-to-end, 82.7% in end-to-side, 72.6% in continuous suture, and 89.5% (arterial) and 62.5% (venous) one-way-up anastomoses, and 58.1% in vein graft technique. "Post-course" survey results indicated that participants considered the most important components of the microcourse to be "practicing on live animals", followed by "the presence of a full-time instructor". In addition, almost all respondents indicated that they were more confident performing clinical microsurgery cases after completing the course., Conclusions: Microvascular surgery requires highly specialized and individualized training to achieve the competences required to perform and master the delicate fine motor skills necessary to successfully handle and anastomose very small and delicate microvascular structures. The ever-expanding clinical applications of microvascular procedures has led to an increased demand for training opportunities. By teaching time-tested basic motor skills that form the foundation of microsurgical technique this international microsurgery-teaching course is helping to meet this demand., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Purpose: Plasma membranes constitute a gathering point for lipids and signaling proteins. Lipids are known to regulate the location and activity of signaling proteins under physiological and pathophysiological conditions. Membrane lipid therapies (MLTs) that gradually modify lipid content of plasma membranes have been developed to treat chronic disease; however, no MLTs have been developed to treat acute conditions such as reperfusion injury following myocardial infarction (MI) and percutaneous coronary intervention (PCI). A fusogenic nanoliposome (FNL) that rapidly incorporates exogenous unsaturated lipids into endothelial cell (EC) membranes was developed to attenuate reperfusion-induced protein signaling. We hypothesized that administration of intracoronary (IC) FNL-MLT interferes with EC membrane protein signaling, leading to reduced microvascular dysfunction and infarct size (IS)., Methods: Using a myocardial ischemia/reperfusion swine model, the efficacy of FNL-MLT in reducing IS following a 60-min coronary artery occlusion was tested. Animals were randomized to receive IC Ringer's lactate solution with or without 10 mg/mL/min of FNLs for 10 min prior to reperfusion (n = 6 per group)., Results: The IC FNL-MLT reduced IS (25.45 ± 16.4% vs. 49.7 ± 14.1%, P < 0.02) and enhanced regional myocardial blood flow (RMBF) in the ischemic zone at 15 min of reperfusion (2.13 ± 1.48 mL/min/g vs. 0.70 ± 0.43 mL/min/g, P < 0.001). The total cumulative plasma levels of the cardiac injury biomarker cardiac troponin I (cTnI) were trending downward but were not significant (999.3 ± 38.7 ng/mL vs. 1456.5 ± 64.8 ng/mL, P = 0.1867). However, plasma levels of heart-specific fatty acid binding protein (hFABP), another injury biomarker, were reduced at 2 h of reperfusion (70.3 ± 38.0 ng/mL vs. 137.3 ± 58.2 ng/mL, P = 0.0115).  CONCLUSION: The IC FNL-MLT reduced IS compared to vehicle in this swine model. The FNL-MLT maybe a promising adjuvant to PCI in the treatment of acute MI.

Until recently, the primo vascular system (PVS) has been unnoticed by most anatomists due to the small diameter and translucent features of the threadlike network. These properties make primo vessels (PVs) difficult to visualize for harvest and for further characterization. One particular PVS subtype that is located within the lymphatic vessels (LVs) is of strong interest because with a proper contrast, these long PVs can be visualized through the transparent LV wall and can be harvested to provide sufficient sample material for analysis. The most common method to visualize this PVS subtype utilizes Alcian blue as the contrast agent. This technique is effective, but tedious, and has relatively low repeatability. The purpose of this study was to develop a new technique that allows reliable visualization of the intralymphatic PVS (IL-PVS) in a user-friendly manner. The method was designed to provide optical contrast to the PVS by taking advantage of the porous nature of the PV's external wall and interstitial matrix. Turquoise-green-colored hollow gold nanospheres (HGNs) in the size range of 50-125 nm were found to provide excellent optical contrast for the IL-PVS in rats. The PVS was visualized within 10 minutes after HGN administration at a 95% success rate., (Copyright © 2015. Published by Elsevier B.V.)

Cervical heterotopic heart transplantation in rodents is a useful tool for studying transplantation immunology. However, end-to-end anastomosis of small-diameter vessels by using standard microsurgical technique is technically difficult and can require prolonged graft ischemia. A novel cuff system was designed from polyethylene tubing to allow anastomosis of vessels with internal luminal diameters of 0.3 to 0.9 mm. Key features include a spring-like adjustable lumen to facilitate vessel eversion, a barb to hold vessel ends in place after eversion, and a handling system that allows easy manipulation and stabilization of cuffs by a single operator. After a training period, a single operator performed a series of 8 transplants in which the mean warm ischemic time of grafts was 8.5 ± 2.9 min. Here we provide a detailed description of how to construct and perform end-to-end vessel anastomosis by using our novel cuff system. The discussion of the technique is supplemented with tips learned during the process of developing a reliable experimental model.

Background: Myocardial injury after heart transplantation is a consequence of pathophysiologic events initiated by local ischemia/reperfusion injury that is further aggravated by the inflammatory response due to blood exposure to the pump's artificial surfaces during cardiopulmonary bypass. The purpose of the present study was to determine the effectiveness of fusogenic lipid vesicles (FLVs) in enhancing the cardioprotective effect of St. Thomas organ preservation solution (ST). We hypothesized that donor hearts preserved with ST+FLVs will stabilize the endothelium during reperfusion, which, in turn, will reduce both endothelial barrier dysfunction and myocardial damage., Methods: To examine the effect of ST+FLVs therapy in vitro, C3b deposition and adhesion molecule expression studies were performed on human umbilical vein endothelial cells challenged with plastic contact-activated plasma. To assess the therapy in vivo, a cervical heterotopic working heart transplantation model in rats was used. Donor hearts were preserved for 1 h at 27°C (15 min) and 4°C (45 min) and, after transplantation, were followed up for 2 h. Left ventricular function and the blood cardiac troponin I levels were quantified., Results: Human umbilical vein endothelial cells treated with ST+FLVs had reduced C3b deposition and expression of adhesion molecules compared with ST alone (P < 0.05). Donor hearts receiving ST+FLVs therapy had reduced left ventricular dysfunction and cardiac troponin I compared with ST alone., Conclusions: We concluded that FLVs enhanced the cardioprotective effect of ST and reduced postischemic left ventricular dysfunction and myocardial damage. The mechanism of protection appears to be associated with the stabilization of endothelial cell membranes owing to incorporation of FLV-derived lipids., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Ischemia-reperfusion injury is a devastating complication that occurs in allotransplantation and replantation of limbs. Over the years, several preservation strategies have been used to conserve the critical levels of intracellular adenosine triphosphate (ATP) during ischemia to sustain the ion gradients across the membranes and thus the tissue viability. The administration of exogenous ATP to ischemic tissues is known to provide beneficial effects during reperfusion, but it is unclear whether it provides protection during ischemia. The purpose of the present study was to determine the effect of ATP administration on high-energy phosphate levels in ischemic skeletal muscle and to examine the role of purinergic and adenosine receptors in mediating the response to exogenous ATP., Methods: The extensor digitorum longus muscles of Fischer rats were subjected to ischemia and treated with different concentrations of ATP with or without purinergic and adenosine receptor blockers. Phosphorus-31 nuclear magnetic resonance spectroscopy was used to measure the rate of decay of ATP, phosphocreatine (PCr), and the formation of adenosine monophosphate and acidification. Phosphorylated compounds were analyzed using a simple model of energy metabolism, and the PCr half-life was used as an index of internal depletion of ATP to distinguish between intracellular and extracellular ATP., Results: PCr decay was rapid in all muscle groups and was followed by gradual ATP decay. The half-life of PCr was significantly longer in the ATP-treated muscles than in the vehicle controls and was maximally prolonged by treating with slow hydrolyzing adenosine 5'-O-(3-thio)triphosphate. Purinoceptor (P2X) blockade with ATP treatment significantly increased the half-life of PCr, and adenosine receptor blockers blunted the response. Administration of adenosine to ischemic muscles significantly increased the half-life of PCr compared with that in the vehicle controls., Conclusions: Exogenous ATP administration to ischemic skeletal muscles appears to spare intracellular energy by acting primarily through adenosine receptors., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Proficient microsurgical skills are considered essential in plastic and reconstructive surgery. Specialized courses offer trainees opportunity to improve their technical skills. Trainee aptitude may play an important role in the ability of a trainee to acquire proficient skills as individuals have differing fundamental abilities. We delivered an intensive 5-day microsurgical training course. We objectively assessed the impact of the course on microsurgical skill acquisition and whether aptitudes as assessed with psychometric tests were related to surgical performance., Methods: Sixteen surgical trainees (male = 10 and female = 6) participated in the courses. Trainees' visual spatial, perceptual, and psychomotor aptitudes were assessed on day 1 of the course. The trainees' performance of an end-to-end arterial anastomosis was assessed on days 2 and 5. Surgical performance was assessed with objective structured assessment of technical skills(OSATS) and time to complete the task., Results: The trainees showed a significant improvement in OSATS scores from days 2 to 5 (P < 0.001) and the time taken to complete the anastomosis (P < 0.001). Aptitude scores correlated strongly with objectively assessed microsurgical skill performance for male trainees but not for females., Conclusions: We demonstrated that participating in a microsurgical training course results in significant improvement in objectively assessed microvascular surgical skills. The degree of skills improvement was strongly correlated with psychomotor aptitude assessments scores for male trainees., (Copyright © 2012 Wiley Periodicals, Inc.)

Background: Excessive complement activation is an integral part of ischemia and reperfusion (IR) injury (IRI) of organs. In kidney transplantation, the pathologic consequence of IRI and complement activation can lead to delayed graft function, which in turn is associated with acute rejection. Previous strategies to reduce complement-induced IRI required systemic administration of agents, which can lead to increased susceptibility to infections/immune diseases. The objective of this study was to determine whether an increase in complement control defenses of rat kidney endothelium reduces IRI. We hypothesized that increased complement control on the endothelial barrier reduces IR-mediated complement activation and reduces kidney dysfunction., Materials and Methods: Fischer 344 rats underwent left kidney ischemia for 45 min and treatment with a novel fusogenic lipid vesicle (FLVs) delivery system to decorate endothelial cells with vaccinia virus complement control protein (VCP), followed by reperfusion for 24 h. Assessment included renal function by serum creatinine and urea, myeloperoxidase assay for neutrophil infiltration, histopathology, and quantification of C3 production in kidneys., Results: Animals in which the kidney endothelium was bolstered by FLVs+VCP treatment had better renal function with a significant reduction in serum creatinine compared with vehicle controls (P < 0.05). Also, C3 production was significantly reduced (P < 0.05) in treated animals compared with vehicle controls., Conclusion: Increasing complement control at the endothelial barrier with FLVs+VCP modulates complement activation/production during the first 24 h, reducing renal dysfunction following IRI., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Ischemia/reperfusion (IR) injury is an unavoidable consequence of tissue transplantation or replantation that often leads to inflammation and cell death. Excessive complement activation following IR induces endothelial cell injury, altering vascular and endothelial barrier function causing tissue dysfunction. To mitigate the IR response, various systemic anti-complement therapies have been tried. Recently, we developed a localized therapy that uses biotinylated fusogenic lipid vesicles (BioFLVs) to first incorporate biotin tethers onto cell membranes, which are then used to bind therapeutic fusion proteins containing streptavidin (SA) resulting in the decoration of cell membranes. The therapy is applied in two steps using solutions delivered intra-arterially., Materials and Methods: Alteration of formulation, concentration and duration of incubation of BioFLVs were conducted to demonstrate the ability of the system to modulate biotin tether incorporation in cultured cells. Using a rat hind limb model, the ability of BioFLVs to decorate endothelium of femoral vessels with FITC-labeled SA for 48 h of reperfusion was demonstrated. The feasibility of a BioFLV-based anti-complement therapy was tested in cultured cells using SA fused with vaccinia virus complement control protein (SA-VCP), a C3 convertase inhibitor. Human ovarian carcinoma (SKOV-3) cells were incubated with BioFLVs first and then with SA-VCP. To activate complement the cells were treated with a SKOV-3-specific antibody (trastuzumab) and incubated in human serum., Results: Decoration of cells with SA-VCP effectively reduced complement deposition., Conclusions: We conclude that BioFLV-mediated decoration of cell membranes with anti-complement proteins reduces complement activation and deposition in vitro and has the potential for application against inappropropriate complement activation in vivo., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Ischemia and reperfusion of organs is an unavoidable consequence of transplantation. Inflammatory events associated with reperfusion injury are in part attributed to excessive complement activation. Systemic administration of complement inhibitors reduces reperfusion injury but leaves patients vulnerable to infection. Here, we report a novel therapeutic strategy that decorates cells with an anti-complement peptide. An analog of the C3 convertase inhibitor Compstatin (C) was synthesized with a hexahistidine (His(6)) tag to create C-His(6). To decorate cell membranes with C-His(6), fusogenic lipid vesicles (FLVs) were used to incorporate lipids with nickel (Ni(2+)) tethers into cell membranes, and these could then couple with C-His(6). Ni(2+) tether levels to display C-His(6) were modulated by changing FLV formulation, FLV incubation time and FLV levels. SKOV-3 cells decorated with C-His(6) effectively reduced complement deposition in a classical complement activation assay. We conclude that our therapeutic approach appears promising for local ex vivo treatment of transplanted organs to reduce complement-mediated reperfusion injury.

Human face transplantation is now a clinical reality. The surgical techniques necessary to perform these procedures have been used routinely in reconstructive microsurgery for many years. From an immunological standpoint since face and hand contain mostly the same tissues it is reasonable to assume that the same immunosuppressive regimen found to be effective in human hand transplants should also work in face transplantation. It is the ethical issues associated with the risks and benefits of performing facial transplantation that have posed the greatest challenges leading up to performing this new procedure. In this editorial, we will review some of the main events that have led to the recently performed human face transplants, specifically focusing on the key ethical issues at the center of this debate. We will discuss how the research and clinical experience in human hand transplantation laid the foundation for performing face transplantation and describe the research and the ethical guidelines upon which a team at the University of Louisville based their position "to move ahead" in spite of much criticism. Finally we will outline some of the key arguments against face transplantation, and conclude with a discussion on what comes next now that the first human face transplants have been performed.

Although the first face transplants have been attempted, the social and psychological debates concerning the ethics and desirability of the procedure continue. Critics contend that these issues have not yet been sufficiently addressed. With this in mind, the present article seeks to elaborate on key psychological and social factors that will be central for addressing the ethical and psychosocial challenges necessary to move face transplantation into mainstream medicine. The goals of this article are to (1) discuss the psychosocial sequelae of facial disfiguration and how face transplantation may relieve those problems, and (2) delineate inclusion and exclusion criteria for the selection of research subjects for face transplantation. The article uses concepts from symbolic interaction theory in sociology to articulate a theoretically coherent scheme for comprehending the psychosocial difficulties of facial disfiguration and the advantages offered by facial transplantation. The authors conclude that the psychosocial implications of disfigurement warrant surgical intervention and that research in the area of face transplantation should continue.

Background: Dynamic myoplasty has many clinical applications and has proven to be a versatile surgical procedure with great promise. This procedure has been used to achieve fecal/urinary continence, as in the dynamic graciloplasty, and to augment cardiac ventricular function, as is commonly seen with dynamic latissimus cardiomyoplasty. In the present study, the authors describe a functional innovative island flap sphincter created from the rectus abdominis muscle in a large-animal model to provide stomal continence for future clinical studies., Methods: The caudal region of the rectus abdominis muscle in eight mongrel canines (23 to 25 kg) was investigated through anatomical dissections during which the location of the neurovascular pedicles and the intersegmental muscle dimensions between the muscle inscriptions were noted. The rectus abdominis muscle was used to create functional dynamic stomal sphincters that were trained with subcutaneously implanted pulse stimulators., Results: The neurovascular pedicles were consistently found in similar locations along the posterior medial aspect of the caudal portion of the canine's rectus abdominis muscle. The vertical height of the deep inferior epigastric pedicle and caudal intercostal nerve muscular mean entry points were 6.75 +/- 1.89 cm and 7.44 +/- 0.86 cm, respectively. The mean caudal intersegmental muscle length of the rectus abdominis muscle used to create the sphincter was 9.69 +/- 1.81 cm., Conclusions: The canine rectus abdominis muscle has reliable anatomical locations where the neurovascular pedicle may be found. This canine muscle may be used to create a continent island flap stomal sphincter. This large-animal sphincter model is versatile, durable, and easy to manipulate, with minimal morbidity to the animal.

Each year an estimated 7-million people in the USA need composite tissue reconstruction because of surgical excision of tumors, accidents and congenital malformations. Limb amputees alone comprise over 1.2 million of these. This figure is more than double the number of solid organs needed for transplantation. Composite tissue allotransplantation in the form of hand and facial tissue transplantation are now a clinical reality. The discovery, in the late 1990s, that the same immunotherapy used routinely in kidney transplantation was also effective in preventing skin rejection made this possible. While these new treatments seem like major advancements most of the surgical, immunological and ethical methods used are not new at all and have been around and routinely used in clinical practice for some time. In this review of composite tissue allotransplantation, we: (i) outline the limitations of conventional reconstructive methods for treating severe facial disfigurement, (ii) review the history of composite tissue allotransplantation, (iii) discuss the chronological scientific advances that have made it possible, (iv) focus on the two unique clinical scenarios of hand and face transplantation, and (v) reflect on the critical issues that must be addressed as we move this new frontier toward becoming a treatment in mainstream medicine.

Background: The immunosuppressant FK506 has been reported to increase the rate of peripheral nerve regeneration in nerve crush injury and nerve allograft models. The purpose of this study was to determine whether low doses of FK506 and mycophenolate mofetil had a neuroregenerative effect in revascularized peripheral nerve allografts in a rat hind limb transplantation model., Methods: Wistar Furth rat recipients received limbs from syngeneic Wistar Furth donors (group 1, n = 4) or from allogeneic August X Copenhagen Irish rat donors (group 2, n = 6). Wistar Furth recipients received limbs from August X Copenhagen Irish donors and were treated with FK506/mycophenolate mofetil for 5 months (group 3, n = 7). At the end of the follow-up period, histomorphometric analysis of sciatic and tibial nerves from transplanted and intact hind limbs was conducted. Sciatic and tibial nerves were examined at the level of coaptation and near the neuromuscular junction, respectively., Results: Transplanted limbs in groups 1 and 3 completed the study without rejection, while the limbs in group 2 were rejected within a few days. Sciatic and tibial nerve analysis in groups 1 and 3 limbs showed myelinated axons of various diameters but in significantly fewer numbers than in nontransplanted contralateral nerves. The number and size of myelinated axons of transplanted nerves at corresponding levels were not significantly different between syngeneic and allogeneic (FK506/mycophenolate mofetil-treated) transplants., Conclusions: The authors conclude that long-term neuroregeneration of revascularized peripheral nerves using low-dose FK506/mycophenolate mofetil was similar to that of syngeneic transplants. The occurrence of acute rejection episodes with low-dose FK506/mycophenolate mofetil did not appear to benefit nor impair neuroregeneration.

Background: The surgical techniques necessary to transplant a human face are well established, and the early success of human hand transplants suggests that the immunological hurdles of transplanting human facial tissues have largely been overcome. Therefore, it is the ethical barriers that pose the greatest challenge to performing facial transplantation. At the center of the ethical debate is the question, "Do the risks posed by the life-long immunosuppression that a recipient would have to take justify the benefits of receiving a face transplant?" In this study, the authors answer this question by assessing the degree of risk individuals would be willing to accept to receive a face transplant., Methods: To quantitatively assess risks versus benefits in facial transplantation, the authors developed the Louisville Instrument for Transplantation, or LIFT, which contains 237 standardized questions. Respondents in three study populations (healthy individuals, n = 150; organ transplant recipients, n = 42; and individuals with facial disfigurement, n = 34) were questioned about the extent to which they would trade off specific numbers of life-years, or sustain other costs, in exchange for receiving seven different transplant procedures., Results: The authors found that the three populations would accept differing degrees of risk for the seven transplant procedures. Organ transplant recipients were the most risk-tolerant group, while facially disfigured individuals were the least risk tolerant. All groups questioned would accept the highest degree of risk to receive a face transplant compared with the six other procedures., Conclusions: This study presents an empirical basis for assessing risk versus benefit in facial transplantation. In doing so, it provides a more solid foundation upon which to introduce this exciting new reconstructive modality into the clinical arena.

Background: The role of lymph nodes (LNs) in adaptive immune responses has been the subject of extensive research. In previous studies, the surgical removal of lymph nodes from rat hind limbs prevented the development of lethal graft-versus-host disease (GVHD) after allogeneic hind limb transplantation to chimeric recipient rats. The purpose of this study was to establish the role of the cellular fraction versus the microenvironment of LNs in the development of GVHD in this model., Methods: A rat model for vascularized LN transplantation was developed and graft-versus-host responses were compared after: 1) naive ACI LN cells were infused into Wistar-Furth (WF) rats as chimeric recipients (e.g. [ACI-->WF]); 2) vascularized WF lymph nodes were transplanted to syngeneic WF recipients; 3) nonvascularized ACI lymph nodes were transplanted to [ACI-->WF] chimeric recipients; 4) vascularized ACI lymph nodes were transplanted to [ACI-->WF] chimeric recipients., Results: Transplantation of vascularized ACI lymph nodes to [ACI-->WF] chimeric recipient rats resulted in severe and sometimes lethal GVHD. In contrast, neither the infusion of purified ACI LN cells nor the transplantation of nonvascularized LNs led to GVHD in chimeric recipients., Conclusions: When introducing allogeneic cells into chimeric recipients, concomitant transplantation of the vascularized LN microenvironment makes a manifest difference between induction and absence of GVHD. This illustrates the important role of the LN microenvironment in adaptive immune responses.

Composite-tissue allotransplantation (CTA) is a new therapeutic modality to reconstruct major tissue defects of the face, larynx, and extremities. Unlike most life-saving organ-transplantation procedures, CTA is considered to improve quality of life. Therefore, the question arises, do the risks posed by the immunosuppression drugs that patients must take to prevent rejection justify the benefits of these procedures? The purpose of this study was to assess the relative risk that individuals are willing to accept in order to receive the benefits of CTA procedures. We used a psychometrically reliable and valid instrument to question two primary populations of individuals: those who live with the risks of immunosuppression, and healthy individuals. The level of risk acceptance for the seven transplant procedures tested (foot, single hand, double hand, larynx, kidney, hemiface, and full face) showed significant differences in research participants' risk acceptance for the different transplant procedures, but no significant differences between groups. Based on these findings, we conclude that certain CTA procedures convey benefits to recipients that are perceived by subjects, including individuals who live with the risks of immunosuppression, to warrant the risks of these procedures., (2006 Wiley-Liss, Inc.)

Background: Tacrolimus (FK506)/mycophenolate mofetil (MMF)/prednisone combination immunosuppression therapy has been found to effectively prevent composite tissue allograft (CTA) rejection with minimal toxicity in a preclinical porcine model. These findings have been reproduced in 24 human hands transplanted in 18 patients. In CTAs containing bone, adequate bone quality and healing are essential for long-term functional success. The purpose of this study was to determine the effect FK506/MMF/prednisone immunotherapy has on bone quality and healing., Methods: Forelimb CTA-flaps were transplanted in nine pigs. Recipient animals received FK506/MMF/prednisone therapy for 3 months. Bone quality was studied pre- and posttransplant by measuring acoustic velocity and density and by calculating elastic coefficients. Additional bone quality analyses were performed on unoperated limbs, and in bone grafts from two pigs that had autograft procedures performed. Bone healing was assessed using radiographic analysis., Results: Three animals were lost to immunosuppression-related complications before the endpoint of the study. The bone component of all six CTA-flaps showed normal healing. Although results of the bone density measurements were not significantly different when comparing pre- to posttransplant values, acoustic velocity and elastic coefficient measurements showed a significant decrease posttransplant indicating a decrease in bone quality., Conclusions: FK506/MMF/prednisone combination therapy prevented rejection, did not adversely affect bone quality, and showed normal bone healing. The transplant procedure itself decreased bone quality more than the immunosuppression regimen did over the observation period in this study. Based on these findings, we conclude to prevent CTA failure it is important to monitor bone quality posttransplant.

Background: The time course of the late phase of ischemic preconditioning (IPC) was determined in latissimus dorsi muscle (LDM) flaps using viability and function as the endpoints., Materials and Methods: LDM flaps from Sprague-Dawley rats were allocated into 6 groups. LDMs were preconditioned with 2 30-minute periods of ischemia separated by 10 minutes of reperfusion and subjected to a 4-hour ischemic insult after 24, 48, 72, and 96 hours from IPC. LDMs were evaluated for percent necrosis and muscle contractile function and compared with controls., Results: The late phase of IPC provides significant protection against necrosis up to 72 hours. Conversely, when the end point used was muscle contractile function, the protection only lasted 48 hours., Conclusion: The time course of late-phase protection in skeletal muscle is 2-3 days. Late phase IPC appears to protect muscle flaps during the most critical time period following elevation.

Although vascularized bone and joint allotransplantation is a promising new treatment option for reconstructing large bone defects, the need for immunosuppressive agents to prevent rejection in these procedures poses a major problem. This problem stems from the fact that several of these agents can cause harmful side effects, such as alterations in bone quality and healing. Therefore, the purpose of this study was to determine what effect the commonly used immunosuppressant regimen cyclosporine A-based combination therapy has on bone quality and healing. In 10 pigs, vascularized bone allografts with skin and muscle components (osteomyocutaneous free flaps) were transplanted from size-matched donor animals. Recipient animals received oral cyclosporine A/mycophenolate mofetil/prednisone therapy for 90 days. Bone quality was studied before and after transplantation by measuring the bone's acoustic velocity and density and calculating the bone's elastic coefficient. Bone healing was assessed using radiographic analysis. Four animals were lost as a result of graft rejection or immunosuppression-related complications before the 90-day endpoint of the study. Although bone specimens taken from the six animals that completed the 90-day protocol had histological signs of rejection, they all seemed to have normal bone healing. Posttransplant bone density values were significantly decreased (p < 0.05) (1544.7 +/- 47.5 kg/m3) as compared with pretransplant values (1722.7 +/- 44.1 kg/m3). Results of the acoustic velocity and elastic coefficients measurements showed a significant decrease (p < 0.05) in posttransplant values (from 3503.0 +/- 165.1 meters/sec to 2963.0 +/- 54.6 meters/sec and from 21.6 +/- 2.2 GPa to 13.6 +/- 0.5 GPa, respectively), indicating diminished bone quality. The findings indicate that cyclosporine A/mycophenolate mofetil/prednisone combination therapy is ineffective in preventing bone rejection, that it decreases bone quality, and that it is associated with systemic toxicity, suggesting that this immunosuppressive regimen at the doses used in this study is not ideal for vascularized bone allotransplantation procedures.

In previous rat studies, the use of mixed allogeneic chimerism (MAC) to induce host tolerance to hind limb allografts has resulted in severe graft-versus-host disease (GVHD). The purpose of this study was to determine if immunocompetent cells in bone marrow (BM) and/or lymph nodes (LNs) of transplanted limbs were responsible for inducing GVHD in mixed chimeric hosts. [ACI-->Wistar Furth] chimeric rats received ACI hind limbs that were non-irradiated, irradiated (1050 cGy) or lymphadenectomized. Rejection, GVHD and donor chimerism was assessed. Chimeric hosts rejected none of their limbs. However, hosts of non-irradiated hind limbs succumbed to GVHD 22.4+/-0.8 days after transplantation. In contrast, chimeras that received irradiated or lymphadenectomized ACI hind limbs showed no clinical or histological signs of GVHD at 5 months. We conclude that mixed chimeric hosts are susceptible to GVHD due to the immunocompetent cell load provided by the LNs, not the BM, of hind limb allografts.

Transplantation continues to push the frontiers of medicine into domains that summon forth troublesome ethical questions. Looming on the frontier today is human facial transplantation. We develop criteria that, we maintain, must be satisfied in order to ethically undertake this as-yet-untried transplant procedure. We draw on the criteria advanced by Dr. Francis Moore in the late 1980s for introducing innovative procedures in transplant surgery. In addition to these we also insist that human face transplantation must meet all the ethical requirements usually applied to health care research. We summarize the achievements of transplant surgery to date, focusing in particular on the safety and efficacy of immunosuppressive medications. We also emphasize the importance of risk/benefit assessments that take into account the physical, aesthetic, psychological, and social dimensions of facial disfiguration, reconstruction, and transplantation. Finally, we maintain that the time has come to move facial transplantation research into the clinical phase.

Background: We and others have shown that mixed allogeneic chimerism induces donor-specific tolerance to composite tissue allografts across major histocompatibility complex barriers without the need for immunosuppression. However, a delay period between bone marrow transplantation and limb allotransplantation is required, making such protocols impractical for clinical application. This study eliminates this delay period in a rat hind limb allotransplantation model by performing mixed allogeneic chimerism induction and transplantation "simultaneously.", Methods: Group 1 included controls in which naïve Wistar Furth (WF) hosts received ACI hind limbs. Group 2 included (ACI-->WF) chimeras that received limbs from third-party donors (Fisher), and group 3 included chimeras that received irradiated (1,050 cGy) ACI limbs. In group 4, WF hosts conditioned with 950 cGy received irradiated (1,050 cGy) ACI limbs followed by infusion of 100 x 10(6) ACI T-cell-depleted bone marrow cells and immunotherapy (tacrolimus and mycophenolate mofetil) for 28 days. Group 5 animals received the same treatment as group 4 animals without immunotherapy., Results: The rats in groups 1 and 2 rejected their limbs within 10 days. Only one rat in group 4 survived to the end of the study. Groups 3 and 5 demonstrated long-term limb survival without rejection or graft-versus-host disease. High levels of donor chimerism (>80%) were achieved and maintained throughout the study. Mixed lymphocyte reaction assays in both groups revealed donor-specific hyporesponsiveness with vigorous third-party reactivity., Conclusions: This study demonstrated that infusion of donor bone marrow cells into conditioned hosts immediately after limb transplantation results in stable mixed chimerism, robust tolerance, and reliable limb allograft survival.

Composite tissue allografts (CTAs) offer an alternative to conventional reconstructive methods. However, the toxicity of the drugs that are required to prevent rejection has prevented its widespread clinical application. The purpose of this study was to determine whether a low-dose, corticosteroid-free combination regimen of tacrolimus and mycophenolate mofetil (MMF) would prevent rejection in a rat hind-limb model, with minimal toxic side effects. Three groups were used in this study. In group I, Wistar Furth (WF) rats received a syngeneic WF hind-limb. In groups II and III, WF rats received an ACI hind-limb. The latter were treated with tacrolimus-MMF. Assessment for rejection, flow cytometry, and mixed lymphocyte reactions was performed. Biopsies were taken regularly and at the time of killing. Combination therapy with low-dose tacrolimus-MMF effectively prolonged CTA survival indefinitely, with minimal side effects. Toxicity associated with immunosuppressive drugs can be avoided in a low-dose combination corticosteroid-free regimen.

Muscle tissue transplantation applied to regain or dynamically assist contractile functions is known as 'dynamic myoplasty'. Success rates of clinical applications are unpredictable, because of lack of endurance, ischemic lesions, abundant scar formation and inadequate performance of tasks due to lack of refined control. Electrical stimulation is used to control dynamic myoplasties and should be improved to reduce some of these drawbacks. Sequential segmental neuromuscular stimulation improves the endurance and closed-loop control offers refinement in rate of contraction of the muscle, while function-controlling stimulator algorithms present the possibility of performing more complex tasks. An acute feasibility study was performed in anaesthetised dogs combining these techniques. Electrically stimulated gracilis-based neo-sphincters were compared to native sphincters with regard to their ability to maintain continence. Measurements were made during fast bladder pressure changes, static high bladder pressure and slow filling of the bladder, mimicking among others posture changes, lifting heavy objects and diuresis. In general, neo-sphincter and native sphincter performance showed no significant difference during these measurements. However, during high bladder pressures reaching 40 cm H(2)O the neo-sphincters maintained positive pressure gradients, whereas most native sphincters relaxed. During slow filling of the bladder the neo-sphincters maintained a controlled positive pressure gradient for a prolonged time without any form of training. Furthermore, the accuracy of these maintained pressure gradients proved to be within the limits set up by the native sphincters. Refinements using more complicated self-learning function-controlling algorithms proved to be effective also and are briefly discussed. In conclusion, a combination of sequential stimulation, closed-loop control and function-controlling algorithms proved feasible in this dynamic graciloplasty-model. Neo-sphincters were created, which would probably provide an acceptable performance, when the stimulation system could be implanted and further tested. Sizing this technique down to implantable proportions seems to be justified and will enable exploration of the possible benefits.

Background: Mixed allogeneic chimerism (MAC) has been shown to induce tolerance to composite tissue allografts (CTA). However, transplantation of unmanipulated donor-specific limbs results in severe graft-versus-host disease (GVHD). This suggests that nontolerant mature donor-derived cells in the CTA may affect the stability of chimerism, potentially resulting in GVHD. The aim of this study was to develop an approach to study and prevent GVHD in a mixed chimeric-rat hind-limb transplantation model., Methods: [ACI-->WF] chimeras received a limb from Wistar Furth (WF) (syngeneic), Fisher (third-party), or ACI (irradiated [1,050 cGy] or nonirradiated) rats. In vitro tolerance was assessed using mixed lymphocyte reactivity (MLR) assays at the time the animals were killed., Results: [ACI-->WF] chimeras with greater than 85% chimerism exhibited rejection-free survival of donor-specific hind limbs. However, 100% of these animals developed lethal GVHD 22.4+/-2.8 days after limb transplantation. [ACI-->WF] chimeras that underwent transplantation with irradiated ACI or syngeneic WF limbs showed no signs of rejection or GVHD at 5 months. Nonchimeric and third-party controls rejected limbs within 10 days., Conclusions: Conditioning of the host WF rats with 950 cGy of irradiation (sublethal, myeloablative) led to high levels of MAC without GVHD. The mature T-cell content of nonirradiated donor (ACI) limbs was sufficient to induce lethal GVHD in 100% of tolerant mixed chimeric [ACI-->WF] hosts. Irradiation of donor limbs before transplantation resulted in long-term donor-specific tolerance and prevented GVHD. These data demonstrate that (1) established chimeras could be susceptible to GVHD caused by immunocompetent donor cells transferred with the hind limb, and (2) inactivating these cells with irradiation prevents GVHD and destabilization of chimerism, and permits rejection-free graft acceptance.

Background: Glycosaminoglycans (GAGs) are heteropolysaccharides present as integral components of the extracellular matrix (ECM), cell and basement membranes. GAGs play an important role in immune and inflammatory responses because of their ability to interact with cytokines and chemokines, promoting the localization of these molecules onto the ECM or cell membranes at specific anatomical sites. The main goal of these studies was to test the hypothesis that interference with the binding of cytokines/chemokines to GAGs will interfere with a graft rejection response., Methods: MC-2, a cationic peptide derived from the sequence of the heparin-binding domain of mouse interferon gamma, was used as an inhibitor of the binding of cytokines/chemokines to GAGs. The effects of this peptide were studied in an allogeneic transplantation model involving vascularized rat skin flaps., Results: The MC-2 peptide was found to inhibit binding of interferon-gamma, as well as that of the chemokines, interleukin-8, interferon gamma inducible protein-10, and regulated on activation normal T cell expressed and secreted (RANTES), to GAGs in vitro. Direct administration of MC-2 in an allogeneic skin flap transplantation model resulted in a significantly delayed time of rejection, from 5.4 +/- 0.5 days (control; n=6) to 12.6 +/- 1.6 days (treated animals; n=10). Histopathologic analysis of the skin biopsies was consistent with the delayed rejection process in those animals receiving the peptide, showing only mild signs of rejection up to day 11 (in contrast, all control animals had rejected their flaps by day 6)., Conclusions: These results are consistent with the idea that GAG-cytokine interactions constitute valid therapeutic targets and suggest the potential applicability of such an approach in the prevention of graft rejection.

Aims: To evaluate the acute and chronic urodynamic effects of electrically stimulated detrusor myoplasty in dogs., Methods: Eight female mongrel dogs were studied acutely and six dogs chronically (0 to 12 weeks postoperatively). Bladders were wrapped with the rectus abdominis muscle, keeping an intact blood supply and at least two intercostal nerves of the flap preserved. Bladders were electrically stimulated with bipolar electrodes inserted into the muscle. Urodynamics and post void residual were measured post operatively in the acute studies and every 2 weeks for 3 months in chronic studies., Results: Acutely, the increase in intravesical pressure was 45+/-7 cm H(2)O, which resulted in a postvoid residual of 26+/-3%. In the chronic study, increases of intravesical pressure sufficient to empty the bladder during myoplasty electrical stimulation were not sustained, although detrusor compliance and flap viability were preserved., Conclusions: The electrically stimulated detrusor myoplasty worked well acutely to increase vesical pressure sufficient to empty the bladder, but the chronically stimulated myoplasty did not maintain efficient bladder emptying primarily due to electrode problems. Further studies with improved electrode material and placement are required before clinical application of the electrically stimulated detrusor myoplasty can be assessed., (Neurourol. Urodynam. 21:516-521, 2002. Copyright Wiley-Liss, Inc.)

Fecal stomal incontinence is a problem that continues to defy surgical treatment. Previous attempts to create continent stomas using dynamic myoplasty have had limited success due to denervation atrophy of the muscle flap used in the creation of the sphincter and because of muscle fatigue resulting from continuous electrical stimulation. To address the problem of denervation atrophy, a stomal sphincter was designed using the most caudal segment of the rectus abdominis muscle, preserving its intercostal innervation as well as its vascular supply. The purpose of the present study was to determine whether this rectus abdominis muscle island flap sphincter design could maintain stomal continence acutely. In this experiment, six dogs were used to create eight rectus abdominis island flap stoma sphincters around a segment of distal ileum. Initially, the intraluminal stomal pressures generated by the sphincter using different stimulation frequencies were determined. The ability of this stomal sphincter to generate continence at different intraluminal bowel pressures was then assessed. In all cases, the rectus abdominis muscle sphincter generated peak pressures well above those needed to maintain stomal continence (60 mmHg). In addition, each sphincter was able to maintain stomal continence at all intraluminal bowel pressures tested.

Several attempts to create a continent stomal sphincter using dynamic myoplasty with limited success have been reported. Denervation atrophy and early muscle fatigue have plagued all reported attempts to make a continent stoma a reality. To address this problem in a series of experiments, we designed a stomal sphincter using the most caudal segment of the rectus abdominis muscle. Then, we performed a study to determine whether a sphincter created with a rectus abdominis muscle island flap could maintain stomal continence in the short term. We found that when stimulated using two different electrical stimulation protocols, in all cases the rectus abdominis muscle sphincter generated peak pressures well above those needed to maintain stomal continence (60 mm Hg). All sphincters were able to maintain stomal continence at all intraluminal bowel pressures tested. We found one of these protocols to be far superior and reached 4 hours of stomal continence after 8 to 10 weeks of electrical stimulation., (Copyright 2001 Wiley-Liss, Inc.)

The purpose of this study was to test the anatomical and functional feasibility of using a gracilis muscle free flap to create a urinary sphincter. Anatomical studies were performed in 12 human cadavers and short-term (n = 7) and long-term (n = 8) functional studies were performed in dogs. In the short-term functional studies, the left gracilis muscle was transferred into the pelvis and wrapped around the urethra and the right gracilis muscle was wrapped around a stent. A cuff electrode was placed on the muscle's nerve pedicle and used to stimulate the neosphincter while peak pressure, fatigue rate, and perfusion measurements were performed. In the long-term functional studies, intramuscular electrodes were inserted into the neosphincter to stimulate the flap. The flaps were wrapped around the urethra and dogs were followed for 16 weeks, during which time urodynamic measurements were performed. Our anatomical studies demonstrated that the gracilis muscle free flap could be transferred into the pelvis to create a urinary neosphincter. Our short-term functional study demonstrated that gracilis muscle free-flap function and perfusion were not compromised by transfer. In our long-term functional study, all neosphincters provided bladder outlet resistance pressures consistent with continence. Our anatomical, short-term, and long-term functional studies indicate that a gracilis muscle free-flap neosphincter is an effective procedure for treating urinary incontinence., (Copyright 2001 Wiley-Liss, Inc.)

Purpose: Many children with spina bifida and other causes of neurogenic bladder rely on clean intermittent catheterization to empty the hyporeflexic or areflexic bladder. Direct bladder and sacral nerve root stimulation have been met with limited success. We studied the electrical stimulation of a rectus abdominis muscle flap wrapped around the bladder to achieve bladder contractility and emptying., Materials and Methods: The feasibility of performing rectus detrusor myoplasty in humans was first studied in 8 cadavers. In male and female cadavers it was possible to wrap the distended bladder completely with the rectus abdominis muscle. The rectus abdominis muscle was surgically dissected with preservation of its insertion on the pubis bone and rotation of its mid section behind the bladder to effect a complete bladder wrap. The deep inferior epigastric artery and veins, and 2 most caudal intercostal nerves were preserved. This unilateral rectus abdominis muscle flap was then electrically stimulated with 2 pairs of bipolar electrodes inserted into the muscle near the nerve entrance. Stimulation frequencies of 40, 60 and 80 Hz. were used in each of the 8 dogs. The increase in intravesical pressure over baseline, compliance and post-void residual were measured. Paired Student's t tests were used for statistical comparisons., Results: The increase in intravesical pressure ranged 35 +/- 5 to 45 +/- 7 cm. H2O at stimulation frequency 40 and 80 Hz., respectively. Post-void residual was 27 +/- 4%, 22 +/- 3% and 26 +/- 3% at stimulation frequencies 40, 60 and 80 Hz., respectively. Intravesical pressure was significantly increased over baseline bladder pressure (p <0.05)., Conclusions: Electrically stimulated detrusor myoplasty results in uniform increases in intravesical pressure and reasonable bladder emptying in an animal model. We are currently investigating detrusor myoplasty in a chronic study to determine whether it can be used for enhanced bladder emptying in children with poor detrusor contractility.

Our laboratory previously developed and used an orthotopic radial forelimb osteomyocutaneous flap in the pig as a preclinical composite tissue allograft (CTA) model. To ensure that it mimicked the clinical situation as closely as possible we developed this model taking many immunologic and reconstructive considerations into account. While our original pig CTA model was ideal for studying the methods of preventing skin, muscle, bone, vessel and nerve rejection, and systemic toxicity, it did not include specialized tissues/structures of a joint and digit. Therefore, we were unable to evaluate rejection of these specialized tissues and their functional properties. Recognizing the importance of assessing joint rejection and function in hand transplantation research we developed a new swine forelimb CTA model that included the animal's medial digit. The present study describes the anatomy and the transplantation technique used in this new preclinical CTA model. We transplanted a radial osteomyocutaneous flap that included the medial digit between two size- (17-21 kg) and age- (6-8-week) matched farm pigs. We removed the digit from the recipient pig's forelimb in continuity with a section of the radial bone and replaced it with the same structure transplanted from a donor pig. After transplantation, a full-length cast was placed on the recipient pig's operated limb and changes in flap color, temperature and the presence of edema were monitored continuously for 6 h, and then regularly at predetermined intervals over 4 days. No weight bearing restrictions were placed on the animal's operated limb. After 4 days, the animal was euthanized. Direct visual monitoring of the allograft during 4 days revealed it was viable with no signs of graft failure due to technical complications associated with the transplant procedure. Upon waking from anesthesia, the animal stood and wandered freely about its cage with no apparent difficulty. Based on the animal's high level of activity at this time, we concluded that the procedure caused it minimal morbidity. At 4 days after the operation, early signs of rejection (skin erythema and edema) were observed. By incorporating a digit into our original CTA pig forelimb model we have made it a better model for performing preclinical hand transplant studies. The added advantage of being able to assess methods of preventing rejection in the specialized joint/digital tissues (articular cartilage, digital flexor and extensor systems, the nail complex) and assess long-term function of these structures is important. The fact that the procedure does not cause major morbidity to the animal makes it possible to conduct long-term graft survival and functional studies.

The development of effective immunosuppressive drugs has made solid organ allotransplantation the preferred approach for treatment of end-organ failure. The benefits of these immunosuppressants outweigh their risks in preventing rejection of lifesaving solid-organ allografts. On the contrary, composite tissue allotransplants are non-lifesaving and whether the risks of immunosuppressants justify their benefits is a subject of debate. Hence, composite tissue allografts (CTA) have not enjoyed widespread clinical application for reconstruction of large tissue defects. Therefore, a method of preventing rejection that would eliminate the need for toxic immunosuppressants is of particular importance in CTA. Bone marrow transplantation (BMT) to establish mixed chimerism induces tolerance to a variety of allografts in animal models. This article reviews mixed chimerism-based tolerance protocols. Their limitations and their relevance to CTA are discussed, highlighting some unique characteristics (high antigenicity and the presence of active bone marrow) that make CTAs different from solid organ allografts.

In conventional dynamic myoplasties, the force generation is poorly controlled. This causes unnecessary fatigue of the transposed/transplanted electrically stimulated muscles and causes damage to the involved tissues. We introduced sequential segmental neuromuscular stimulation (SSNS) to reduce muscle fatigue by allowing part of the muscle to rest periodically while the other parts work. Despite this improvement, we hypothesize that fatigue could be further reduced in some applications of dynamic myoplasty if the muscles were made to contract according to need. The first necessary step is to gain appropriate control over the contractile activity of the dynamic myoplasty. Therefore, closed-loop control was tested on a sequentially stimulated neosphincter to strive for the best possible control over the amount of generated pressure. A selection of parameters was validated for optimizing control. We concluded that the frequency of corrections, the threshold for corrections, and the transition time are meaningful parameters in the controlling algorithm of the closed-loop control in a sequentially stimulated myoplasty.

Purpose: To reconstruct an electrically stimulated muscular urinary sphincter (MUS) using a tailored gracilis muscle free flap with intact nerve., Materials and Methods: Unilateral surgically tailored gracilis muscle free flaps were transferred into the pelvis in eight dogs, leaving the obturator nerve intact. The muscle's pedicle vessels were anastomosed to the inferior epigastric artery and vein in the pelvis and the muscle was wrapped around the bladder neck. Electrodes were inserted into the MUS and connected to a programmable pulse generator. After 8 weeks of training the MUS, the pulse generator was programmed to be "on" for 4 hours and "off' for 15 minutes in a continuous cycle. Urodynamic studies were performed periodically, and at the end of the experiment the MUS and proximal urethra were harvested for histology. Three control dogs had sham operations., Results: All MUS's functioned well following the procedure. Histology of the MUS/urethra complex showed no evidence of stricture. Except for one dog, all urethras were easily catheterized., Conclusions: This electrically stimulated innervated free-flap MUS technique effectively increases bladder outlet resistance without producing urethral obstruction.

In electrically stimulated (dynamic) graciloplasty for urinary incontinence, the gracilis muscle is transposed into the pelvis, and the distal part is used to reconstruct a neosphincter. Clinical outcomes using this technique have been disappointing due to stricture of the urethra caused by ischemia in the distal part of the gracilis and limited gracilis length available for neosphincter construction. Furthermore, the urethra is twisted by the contracting gracilis, rather than circumferentially squeezed. The purpose of the present study was to test the anatomical and functional feasibility of a new surgical approach to reconstruct a urinary sphincter, using the gracilis muscle as a free flap. In 12 human cadavers, the anatomical feasibility for creating a neosphincter by using the gracilis free flap was determined. In all cases, transfer of the gracilis muscle into the pelvis as a free flap (with the nerve intact) was feasible, and ample muscle was available to construct a neosphincter around the bladder neck. Gracilis neosphincter function was studied in seven dogs. The left gracilis muscle was subjected to transfer into the pelvis as an innervated free flap to create a neosphincter around the urethra. The right (control) gracilis muscle was lifted as a single pedicle flap, remained in situ, and was wrapped around a stent to mimic the urethra. Function (expressed as peak pressure generation and fatigue rate) and surface perfusion were determined for all gracilis muscles. In each dog, both sides were compared using the paired Student's t test for statistical analysis, and no significant difference was measured for the two groups. In conclusion, an innervated gracilis free flap can be used to create a neosphincter around the bladder neck. In an acute study in dogs, function and perfusion of the innervated gracilis free flap are not compromised.