OPTN/SRTR 2022 Annual Data Report: Vascularized Composite Allograft.

This year's chapter on vascularized composite allograft (VCA) encompasses reviews of data collected from 2014 (when VCA was included in the Final Rule) through 2022. The present Annual Data Report shows that the number of VCA recipients in the United States continues to be small and has remained consistent from the prior report. The data continue to be limited by sample size, with trends persistently demonstrating a predominance of White males in the young/middle-aged population as both donors and recipients for nonuterus VCA transplants, and White women younger than 35 years as the predominant recipients of uterus transplant. Similar to the 2021 report, there were only eight failed uterus grafts and one failed nonuterus VCA graft reported from 2014 through 2022. Standardization of definitions of success and failure as well as outcome measures for the different VCA types remain unmet needs in VCA transplantation.

Acute Rejection Rates in Vascularized Composite Allografts: A Systematic Review of Case Reports.

INTRODUCTION: Vascularized Composite Allografts (VCA) are usually performed in a full major histocompatibility complex mismatch setting, with a risk of acute rejection depending on factors such as the type of immunosuppression therapy and the quality of graft preservation. In this systematic review, we present the different immunosuppression protocols used in VCA and point out relationships between acute rejection rates and possible factors that might influence it. METHODS: This systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We systematically searched Medline (PubMed), Embase, and The Cochrane Library between November 2022 and February 2023, using following Mesh Terms: Transplant, Transplantation, Hand, Face, Uterus, Penis, Abdominal Wall, Larynx, and Composite Tissue Allografts. All VCA case reports and reviews describing multiple case reports were included. RESULTS: We discovered 211 VCA cases reported. The preferred treatment was a combination of antithymocyte globulins, mycophenolate mofetil (MMF), tacrolimus, and steroids; and a combination of MMF, tacrolimus, and steroids for induction and maintenance treatment, respectively. Burn patients showed a higher acute rejection rate (P = 0.073) and were administered higher MMF doses (P = 0.020). CONCLUSIONS: In contrast to previous statements, the field of VCA is not rapidly evolving, as it has encountered challenges in addressing immune-related concerns. This is highlighted by the absence of a standardized immunosuppression regimen. Consequently, more substantial data are required to draw more conclusive results regarding the immunogenicity of VCAs and the potential superiority of one immunosuppressive treatment over another. Future efforts should be made to report the VCA surgeries comprehensively, and muti-institutional long-term prospective follow-up studies should be performed to compare the number of acute rejections with influencing factors.

Machine Perfusion Enables 24-h Preservation of Vascularized Composite Allografts in a Swine Model of Allotransplantation.

The current gold standard for preserving vascularized composite allografts (VCA) is 4°C static cold storage (SCS), albeit muscle vulnerability to ischemia can be described as early as after 2 h of SCS. Alternatively, machine perfusion (MP) is growing in the world of organ preservation. Herein, we investigated the outcomes of oxygenated acellular subnormothermic machine perfusion (SNMP) for 24-h VCA preservation before allotransplantation in a swine model. Six partial hindlimbs were procured on adult pigs and preserved ex vivo for 24 h with either SNMP (n = 3) or SCS (n = 3) before heterotopic allotransplantation. Recipient animals received immunosuppression and were followed up for 14 days. Clinical monitoring was carried out twice daily, and graft biopsies and blood samples were regularly collected. Two blinded pathologists assessed skin and muscle samples. Overall survival was higher in the SNMP group. Early euthanasia of 2 animals in the SCS group was linked to significant graft degeneration. Analyses of the grafts showed massive muscle degeneration in the SCS group and a normal aspect in the SNMP group 2 weeks after allotransplantation. Therefore, this 24-h SNMP protocol using a modified Steen solution generated better clinical and histological outcomes in allotransplantation when compared to time-matched SCS.

Significantly Improved Cold Preservation of Rat Hind Limb Vascularized Composite Allografts Using the New PrC-210 Free Radical Scavenger.

Vascularized composite allotransplantation (VCA) represents a promising reconstructive solution primarily conducted to improve quality of life. However, tissue damage caused by cold-ischemia (CI) storage prior to transplant represents a major factor limiting widespread application. This study investigates the addition of the novel free radical scavenger PrC-210 to UW Organ Preservation Solution (UW Solution) to suppress CI-induced skeletal muscle injury in a rat hind limb amputation model. Lewis rats received systemic perfusion of UW solution +/- PrC-210 (0 mM control, 10 mM, 20 mM, 30 mM, or 40 mM), followed by bilateral transfemoral amputation. Limbs were stored in 40 mL of the same perfusate at 4 °C for 48 h. Muscle punch biopsies were taken at set times over the 48 h cold-storage period and analyzed for caspase-3,7 activity, cytochrome C levels, and qualitative histology. A single 15 s perfusion of PrC-210-containing UW Solution conferred a dose-dependent reduction in CI-induced muscle cell death over 48 h. In the presence of PrC-210, muscle cell mitochondrial cytochrome C release was equivalent to 0 h controls, with profound reductions in the caspase-3,7 apoptotic marker that correlated with limb histology. PrC-210 conferred complete prevention of ROS-induced mitochondrial lysis in vitro, as measured by cytochrome C release. We conclude that the addition of 30 mM PrC210 to UW Solution conferred the most consistent reduction in CI limb damage, and it warrants further investigation for clinical application in the VCA setting.

Lymphadenopathy and lymph node rejection following facial vascularized composite allotransplantation.

BACKGROUND: Apart from the skin, little is known about the immunological processes in deeper tissues, which are typically not accessible to biopsy and inspection, of vascularized composite allografts (VCAs). Face transplant patients develop prominent adenopathy shortly after transplantation that resolves over time. The mechanisms underlying this process are not understood. MATERIALS AND METHODS: A retrospective cohort study was conducted on 9 patients who underwent 10 facial VCAs at the Brigham and Women's Hospital, Boston, MA, between April 2009 and July 2019. Clinical, radiological, and histological data related to lymphadenopathy of the head and neck were reviewed. RESULTS: Patients who received donor-derived lymph nodes (LNs) developed bilateral lymphadenopathy of the submental or submandibular superficial LNs. Median time of presentation was POD18 (range POD6-POM3). Notably, bilateral adenopathy of the neck was not observed in later stages of follow-up (mean follow-up, 115 months). Histology of 3 LNs showed increased histiocytes and apoptosis, with the features reminiscent of necrotizing histiocytic lymphadenitis, and B and T lymphocytes (mostly CD8 + T) admixed with CD163 + histiocytes and dendritic cells. Molecular chimerism analysis in one case showed the coexistence of donor (81%) and recipient (19%) derived lymphocytes. Granzyme B (GZMB) expression confirmed the presence of increased cytotoxic T cells in this LN sample. CONCLUSION: Our data suggested the involvement of an immunological process within the donor-derived LNs after facial allotransplantation between the recipient and donor cells. GZMB expression suggested LN rejection that can occurred independently of skin rejection. This finding supports the need to better define the role of donor-derived immune cells in the context of allograft rejection.

The contribution of the donor vascularised hand and face allograft in transplant rejection: An immunological perspective.

Overcoming immunological rejection remains a barrier to the safe adoption of Vascularised Composite Allotransplantation (VCA). To mitigate this risk, clinical protocols have been derived from solid organ transplantation, targeting recipient immunomodulation, yet VCA is unique. Face and hand composite allografts are composed of multiple different tissues, each with their own immunological properties. Experimental work suggests that allografts carry variable numbers and populations of donor leukocytes in an organ specific manner. Ordinarily, these passenger leukocytes are transferred from the donor graft into the recipient circulation after transplantation. Whether alloantigen presentation manifests as acute allograft rejection or transplant tolerance is unknown. This review aims to characterise the immunological properties of the constituent parts of the donor face and hand, the potential fate of donor leukocytes and to consider theoretical graft specific interventions to mitigate early rejection.

Depletion of donor dendritic cells ameliorates immunogenicity of both skin and hind limb transplants.

Acute cellular rejection remains a significant obstacle affecting successful outcomes of organ transplantation including vascularized composite tissue allografts (VCA). Donor antigen presenting cells (APCs), particularly dendritic cells (DCs), orchestrate early alloimmune responses by activating recipient effector T cells. Employing a targeted approach, we investigated the impact of donor-derived conventional DCs (cDCs) and APCs on the immunogenicity of skin and skin-containing VCA grafts, using mouse models of skin and hind limb transplantation. By post-transplantation day 6, skin grafts demonstrated severe rejections, characterized by predominance of recipient CD4 T cells. In contrast, hind limb grafts showed moderate rejection, primarily infiltrated by CD8 T cells. Notably, the skin component exhibited heightened immunogenicity when compared to the entire VCA, evidenced by increased frequencies of pan (CD11b-CD11c+), mature (CD11b-CD11c+MHCII+) and active (CD11b-CD11c+CD40+) DCs and cDC2 subset (CD11b+CD11c+ MHCII+) in the lymphoid tissues and the blood of skin transplant recipients. While donor depletion of cDC and APC reduced frequencies, maturation and activation of DCs in all analyzed tissues of skin transplant recipients, reduction in DC activities was only observed in the spleen of hind limb recipients. Donor cDC and APC depletion did not impact all lymphocyte compartments but significantly affected CD8 T cells and activated CD4 T in lymph nodes of skin recipients. Moreover, both donor APC and cDC depletion attenuated the Th17 immune response, evident by significantly reduced Th17 (CD4+IL-17+) cells in the spleen of skin recipients and reduced levels of IL-17E and lymphotoxin-α in the serum samples of both skin and hind limb recipients. In conclusion, our findings underscore the highly immunogenic nature of skin component in VCA. The depletion of donor APCs and cDCs mitigates the immunogenicity of skin grafts while exerting minimal impact on VCA.

Topical Tacrolimus and Mycophenolic Acid Therapy Synergizes with Low Dose Systemic Immunosuppression to Sustain Vascularized Composite Allograft Survival.

AIM: The goal of this study was to evaluate whether topical administration of tacrolimus (TAC) and mycophenolic acid (MPA) at the transplant site enables vascularized composite allograft (VCA) survival with significant minimization of the dose and adverse effects of systemic TAC (STAC) immunosuppression. MATERIALS AND METHODS: Lewis (Lew) rats received orthotopic hind limb allotransplants from fully mismatched Brown Norway (BN) donors. Group 1 (Controls) received no treatment. Other groups were treated with STAC at a dose of 1 mg/kg/day for 7 days. On post-operative day (POD) 8, the STAC dose was dropped to 0.1 mg/kg/day for Group 2 and maintained at 1 mg/kg for Group 3. Group 4 received topical application of TAC and MPA on the transplanted (Tx) limb starting POD 8 without STAC. Group 5 received topical TAC and MPA on the contralateral non-Tx limb and Group 6 received topical TAC and MPA on the Tx limb starting POD 8 along with low dose STAC (0.1 mg/kg/day). Treatment was continued until the study end point was reached, defined as either grade 3 rejection or allograft survival exceeding 100 days. .We conducted sequential LC-MS/MS measurements to assess TAC and MPA concentrations in both blood/plasma and allograft tissues. Additionally, we evaluated markers indicative of organ toxicity associated with STAC immunosuppression. RESULTS: Compared to controls, topical therapy with TAC+MPA significantly prolonged allograft survival beyond 100 daysat very low dose STAC (0.1 mg/kg/day) (Group 6). The histopathological assessment of the grafts was consistent with the clinical outcomes. .Drug levels in blood/plasma remained low or undetectable, while allograft tissues showed higher drug concentrations compared to contralateral limb tissues (P<0.05). . Urinary creatinine clearance remained within the normal range at 2.5 mL/min. CONCLUSION: Combination therapy with topical TAC and MPA synergizes with a very low dose, corticosteroid- free-STAC regimen and facilitates rejection-free, prolonged VCA survival without morbidity.

A local drug delivery system prolongs graft survival by dampening T cell infiltration and neutrophil extracellular trap formation in vascularized composite allografts.

Introduction: The standard treatment for preventing rejection in vascularized composite allotransplantation (VCA) currently relies on systemic immunosuppression, which exposes the host to well-known side effects. Locally administered immunosuppression strategies have shown promising results to bypass this hurdle. Nevertheless, their progress has been slow, partially attributed to a limited understanding of the essential mechanisms underlying graft rejection. Recent discoveries highlight the crucial involvement of innate immune components, such as neutrophil extracellular traps (NETs), in organ transplantation. Here we aimed to prolong graft survival through a tacrolimus-based drug delivery system and to understand the role of NETs in VCA graft rejection. Methods: To prevent off-target toxicity and promote graft survival, we tested a locally administered tacrolimus-loaded on-demand drug delivery system (TGMS-TAC) in a multiple MHC-mismatched porcine VCA model. Off-target toxicity was assessed in tissue and blood. Graft rejection was evaluated macroscopically while the complement system, T cells, neutrophils and NETs were analyzed in graft tissues by immunofluorescence and/or western blot. Plasmatic levels of inflammatory cytokines were measured using a Luminex magnetic-bead porcine panel, and NETs were measured in plasma and tissue using DNA-MPO ELISA. Lastly, to evaluate the effect of tacrolimus on NET formation, NETs were induced in-vitro in porcine and human peripheral neutrophils following incubation with tacrolimus. Results: Repeated intra-graft administrations of TGMS-TAC minimized systemic toxicity and prolonged graft survival. Nevertheless, signs of rejection were observed at endpoint. Systemically, there were no increases in cytokine levels, complement anaphylatoxins, T-cell subpopulations, or neutrophils during rejection. Yet, tissue analysis showed local infiltration of T cells and neutrophils, together with neutrophil extracellular traps (NETs) in rejected grafts. Interestingly, intra-graft administration of tacrolimus contributed to a reduction in both T-cellular infiltration and NETs. In fact, in-vitro NETosis assessment showed a 62-84% reduction in NETs after stimulated neutrophils were treated with tacrolimus. Conclusion: Our data indicate that the proposed local delivery of immunosuppression avoids off-target toxicity while prolonging graft survival in a multiple MHC-mismatch VCA model. Furthermore, NETs are found to play a role in graft rejection and could therefore be a potential innovative therapeutic target.

Utilización de colgajo radial para cobertura de exposición protésica en craneoplastias / Use of radial flap to cover prosthetic exposure in cranioplasty

Background. Cranioplasty is a procedure that provides coverage for cranial defects after bone resection because of different etiologies such as intracranial hemorrhage, trauma, tumor or infection. One of the most important postoperative complications is the exposure of the plate, that may happen after a skin wound dehiscence. These are challenging situations for the plastic surgeon. Free tissue transfer provides a solution for these patients. The forearm radial flap provides all the conditions to solve these problem Methods. A retrospective study was performed with fourteen patients at the Santojanni Hospital between January 2018 and March 2020. All of them presented exposure of the cranioplasty plate. The defect area was analyzed. The average area to be covered was 5.07 cm2 (1.5 cm2-12.8 cm2). A radial forearm free flap was performed for all patients. Homolateral facial vessels (57%) were used as the first choice; the contralateral facial vessels were used in case of previous radiation therapy (29%) and in these cases a bypass was used in one case with venous interposition in three cases and arterial in the rest; superficial temporal vessels (14%). Results. Flap vitality was 100%. Average follow-up of 12 months (23 m-4 m). One patient presented seroma in the donor area. No new exposures or dehiscences were presented. Conclusions. Free tissue transfer provides an effective coverage to exposed material. The forearm flap provides reliable, thin, well-vascularized soft tissue that can be used to seal the dura, remove dead space, cover the exposed defect, not only but also it provides a long pedicle that allows distant anastomosis in cases of radiation therapy.

Introducción. La craneoplastia es un procedimiento necesario para cubrir defectos craneales luego de resección ósea por distintas etiologías, tales como hemorragia intracraneal, traumatismos craneoencefálicos, tumores o infecciones. Una de las complicaciones frecuentes es la exposición de placas de craneoplastia por dehiscencia de herida cutánea. Estas son complicaciones frecuentes y frustrantes para el paciente y el cirujano plástico. La transferencia de tejidos a distancia brinda una solución para estos pacientes. El colgajo radial antebraquial reúne las condiciones necesarias para la cobertura. Material y métodos. Se realiza un estudio retrospectivo con un total de 14 pacientes en el Hospital Santojanni en el período comprendido entre enero de 2018 y marzo de 2020. Todos presentaron exposición de la placa de craneoplastia. Se analizó el área de defecto, siendo el área promedio a cubrir de 5,07 cm2 (1,5-12,8 cm2). Se realiza cobertura con colgajo radial antebraquial. Se utilizan vasos faciales homolaterales (57%) como primera elección; vasos faciales contralaterales, por radioterapia (29%) y en ellos se utilizó bypass en un tiempo con interposición venosa en tres casos y arterial en el restante; vasos temporales superficiales (14%). Resultados. Se logró cobertura completa en todos los pacientes. La vitalidad de los colgajos fue del 100%. Seguimiento promedio de 12 meses (4-23 meses). Un paciente presentó seroma en la zona dadora. No se presentaron nuevas exposiciones ni dehiscencias. Conclusiones. La transferencia con tejido a distancia permite una eficaz cobertura de material expuesto. El colgajo antebraquial proporciona tejido blando confiable, delgado y bien vascularizado, que se puede utilizar para sellar la duramadre, eliminar el espacio muerto, cubrir el defecto expuesto y también posee un pedículo largo que permite anastomosis a distancia en casos de defectos tratados con radioterapia. Palabras claves: complicaciones de craneoplastias, reconstruccion de cuero cabelludo,

Xenoenxerto (pele da Tilápia-do-Nilo) e hidrofibra com prata no tratamento das queimaduras de II grau em adultos / Nile tilapia skin xenograft versus silver-based hydrofiber dressing in the treatment of second-degree burns in adults

Introdução: Estudos recentes apontam a utilização do curativo biológico com base em animais aquáticos como biomaterial na medicina regenerativa, apresentando boa aderência ao leito das feridas. O objetivo foi avaliar a eficácia da utilização da pele da Tilápia-do-Nilo (Oreochromis niloticus) como curativo biológico oclusivo, no manejo/tratamento de queimaduras de 2º grau em adultos. Métodos: Estudo clínico com 30 pacientes aleatoriamente tratados com pele da Tilápia-do-Nilo (n = 15) e hidrofibra com prata Aquacel Ag® (n =1 5). Resultados: Em relação à duração, o tratamento com a pele da Tilápiado-Nilo obteve uma média de dias de tratamento (9,6 ± 2,4) similar ao material comparativo (10,7 ± 4,5). Quanto ao relato de dor durante a troca de curativos, não houve diferença estatisticamente significante (p > 0,68) entre os grupos. Após a troca do curativo, não houve inferioridade no registro do valor na escala analógica de dor, em que 66,7% dos tratados com pele da Tilápia-do-Nilo relataram diminuição dos eventos álgicos. Constatou-se ainda que 60% dos pacientes tratados com a pele da Tilápia-do-Nilo não tiveram seus curativos substituídos em qualquer momento do tratamento. Para o curativo Aquacel AG®, 53,3% dos pacientes tiveram mais de uma substituição de curativos. Conclusões: Com base na pesquisa, pode-se concluir que a pele da Tilápia-do-Nilo é eficaz como curativo biológico oclusivo. Houve similaridade entre os grupos para a média de dias de tratamento (completa cicatrização da ferida) e para o relato de dor durante a realização do curativo. Também, a não inferioridade relacionada a dor após os curativos e suas trocas (quando existentes) e na quantidade de substituições destes.

Introduction: Recent studies have suggested the use of biological dressings made of aquatic animals as biomaterials in regenerative medicine since they demonstrate good adherence to the wound bed. The objective of this study was to evaluate the efficacy of Nile tilapia skin (Oreochromis niloticus) as an occlusive biological dressing in the management and treatment of second-degree burns in adults. Methods: This clinical study included 30 patients randomly treated with Nile tilapia skin (n = 15) or Aquacel Ag® silver-based hydrofiber dressing (n = 15). Results: The Nile tilapia skin yielded a similar mean treatment time (9.6 ± 2.4 days) to that of the comparative material (10.7 ± 4.5 days). There was no statistically significant intergroup difference (p > 0.68) in pain during dressing changes. No disadvantage in pain was noted, as 66.7% of patients treated with Nile Tilapia skin reported a decrease in pain events. Moreover, 60% of the patients treated with the Nile Tilapia skin did not require dressing replacement at any time during treatment. For the Aquacel AG® dressing, 53.3% of the patients required more than one dressing replacement. Conclusions: Our findings suggest that the Nile tilapia skin is as effective as an occlusive biological dressing. The average treatment time (complete wound healing) and pain reports during dressing changes were similar between groups. Furthermore, pain after and number of dressing exchanges (when performed) were not worse.

Reintegração de amputação digital distal com enxerto composto e difusão plasmática ampliada distal no plano dérmico palmar - relato de um caso em criança de 2 anos de idade e revisão da literatura / Reintegration of distal digital amputation with composite graft and plasmatic diffusion expanded distally on the palmar dermal plane - a case report of a 2-year-old child and a literature review

Nas amputações mais distais da ponta dos dedos, o reimplante microcirúrgico pode não ser praticável. Nestes casos, o enxerto composto oferece os melhores resultados funcionais e estéticos, sendo, porém, incerta a sua reintegração. Várias técnicas foram aventadas para melhorar a sobrevida do enxerto volumoso, basicamente diminuindo o seu volume, associando ou não um retalho cutâneo. Outras técnicas criam uma superfície adicional de contato para difusão plasmática, o "bolso subcutâneo", sem diminuir o volume do enxerto composto, com altas taxas de sucesso. O presente artigo apresenta um caso de amputação da ponta distal do dedo mínimo (zona I de Ishikawa) numa criança de 2 anos de idade. Impossível de reimplante microcirúrgico, a reintegração foi feita com enxerto composto do coto amputado, sem desbridamento, e com a criação de uma nova superfície de contato para difusão plasmática, na extremidade distal do coto enxertado, no plano dérmico da região hipotênar, aumentando assim a área de contato e diminuindo a distância radial da difusão plasmática no enxerto composto. Doze dias após, esse contato adicional foi separado e ambas as superfícies apresentaram sangramento. A reintegração foi total, com mínimas cicatrizes no dedo e na região hipotênar. Uma breve revisão bibliográfica foi feita e discutidos os conceitos cirúrgicos, assim como os fatores que influenciam na sobrevida do enxerto composto. Na área receptora, o plano anatômico mais adequado e melhor vascularizado, para o contato adicional com o enxerto, necessita ser determinado.

In more-distal amputations of the fingertips, microsurgical replantation is not feasible. For these cases, composite graft provides the best functional and aesthetic results. However, its reintegration is uncertain. Several techniques have been proposed to improve bulky graft survival by basically reducing its volume, regardless of whether a skin flap is connected. Other techniques create an additional contact surface for plasmatic diffusion, the so-called subcutaneous pocket, without reducing the composite graft volume and yielding high success rates. This article presents a case of amputation of the distal tip of the fifth digit (Ishikawa zone I) of a 2-year-old child. Because of the impossibility of microsurgical replantation, a composite graft was used to reintegrate the amputated stump, without debridement, by creating a new contact surface for plasmatic diffusion at the distal end of the grafted stump, on the dermal plane in the hypothenar region, thereby increasing the contact area and decreasing the radial distance for the plasmatic diffusion of the composite graft. Twelve days later, the additional contact was separated and both surfaces presented bleeding. Full reintegration occurred with minimal scarring of the finger and hypothenar region. A brief literature review was conducted, discussing surgical concepts and factors that influence composite graft survival. The most appropriate and best vascularized anatomic plane for additional contact with the graft in the recipient area needs to be determined.

Reconstrucción auricular del tercio inferior de la oreja. Caso problema / Atrial reconstruction of the lower third of the ear. Problem case

En la búsqueda de dar solución a defectos del tercio inferior de la oreja se han utilizado diversas técnicas reconstructivas que abarcan desde la colocación de injertos compuestos contralaterales hasta el tallado de colgajos, que dependen de la cesión de tejidos vecinos. Aquí exponemos una opción válida: el colgajo de Antia-Buch aplicado al tercio inferior, con un resultado aceptable, sin agregar más zonas de comorbilidad a la existente

In the search of solution forthe lower third defects of the ear there have been used diverse reconstructions technics, from harvested of composite grafts till local fl aps, that depends from a near donor zone. Here we show a valid option: the AntiaBuch fl ap in application for the lower third of the ear, with an acceptable result, without adding extra morbidity to the zone

Utilización shunt arteriovenoso en Cirugía Reconstructiva / Use of arteriovenous shunt in Reconstructive surgery

La reconstrucción secundaria determinada por traumatismos severos de alta energía y procedimientos oncológicos con grandes pérdidas de cobertura cutánea requiere la transferencia con microcirugía para aportar un tejido sano vascularizado al sector comprometido. Sin embargo, debido a procesos cicatriciales y traumáticos, no siempre es posible hallar los vasos receptores para la transferencia. Una solución a dicha dificultad es la utilización de injertos venosos y arteriales o la confección de una fístula arteriovenosa cercana a la pérdida de sustancia. Se crea una fístula arteriovenosa temporalmente y luego se dividirá aportando los vasos necesarios para el colgajo libre. Desde agosto 2007 a agosto 2011 se realizaron 28 fístulas arteriovenosas en 27 pacientes que han sido utilizadas para transferencia de 22 colgajos libres. Las edades de los pacientes van desde los 12 a los 65 años de edad, con una media de 40,44 años. el tiempo de seguimiento de estos pacientes va desde los 2 hasta los 48 meses. De las 28 fístulas realizadas, 22 han podido ser utilizadas para transferir colgajos libres en forma exitosa. Las otras 6 fallaron. Las fístulas arteriovenosas determinaron cambios fisiológicos y en las características de flujo que permitió mayor seguridad en el momento de la transferencia de los colgajos. La utilización de fístulas arteriovenosas permite no sólo tener vasos receptores de buena calidad próximos a la lesión, sino también conseguir con ellas, un mayor flujo sanguíneo arterial y disminución de las resistencias periféricas gracias a cambios fisiológicos e histológicos que se producen a nivel del puente arteriovenoso.