Free flap rescue using an extracorporeal perfusion device

Impact of perioperative anticoagulation management on free flap survival in reconstructive surgery: a retrospective analysis

BACKGROUND

Despite advancements in surgical techniques and perioperative care for free flap reconstructive surgery, concerns persist regarding the risk of free flap failure, with thrombosis and bleeding being the most common complications that can lead to flap loss. While perioperative anticoagulation management is crucial for optimizing outcomes in free flap reconstructive surgery, standardized protocols remain lacking. This study aims to investigate the role of anticoagulation and perioperative practices in free flap reconstructive surgery and their impact on surgical outcomes.

METHODS

This retrospective, single-center study included all adult patients undergoing free flap surgery from 2009 to 2020. Patients were retrospectively divided based on intraoperative (UFH or no UFH) and postoperative anticoagulation management (UFH only, Aspirin and UFH, Aspirin only). The relationship between anticoagulation protocols, PTT values, and flap survival was assessed.

RESULTS

A total of 489 free flap surgeries were included. Most flaps were taken from the upper extremity (49.5%), primarily for tumor-related reconstructions (85.7%). Flap loss occurred in 14.5% of cases, with a median time to flap loss of 3 days post-surgery. Intraoperative UFH (20 IU/kg) was administered to 63.6% of patients and significantly predicted flap survival (OR = 0.45, 95% CI [0.24, 0.82]). PTT values on day 1 post-surgery were significantly related to flap survival (P = 0.03), with each unit increase reducing the relative probability of flap loss by 5.2%. There was no significant difference in flap survival between patients treated with heparin alone and those treated with both heparin and aspirin. The small sample size in the aspirin-only group limited the statistical relevance of this subgroup.

CONCLUSION

Our findings highlight the importance of intraoperative UFH and PTT-guided postoperative management in improving free flap survival. Standardized anticoagulation protocols are essential for enhancing outcomes in free flap reconstructive surgery.

A Guide to the Implementation and Design of Ex Vivo Perfusion Machines for Vascularized Composite Allotransplantation

Background

Ex vivo machine perfusion (EVMP) is a versatile platform utilized in vascularized composite allotransplantation (VCA) to prolong preservation, salvage tissue, and evaluate graft viability. However, there is no consensus on best practices for VCA. This article discusses the common components, modifications, and considerations necessary for a successful VCA perfusion.

Methods

A systematic literature review was performed in several databases (PubMed, Scopus, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov) to identify articles published on VCA EVMP (face, limb, abdominal wall, uterus, penis, and free flaps) before August 2022. Graft type and animal model, general perfusion parameters, core components of the circuit, and optional components for enhanced monitoring were extracted from the articles.

Results

A total of 1370 articles were screened, and 46 articles met inclusion criteria. Most articles (84.8%) were published in the last 10 years. Pigs were the main model used, but 10 protocols used human grafts. Free flaps were the most common graft type (41.3%), then upper extremities/forelimbs (28.3%), uteruses (17.4%), and hindlimbs (13.0%). Postperfusion replantation occurred in 15.2% of studies. Normothermic perfusion predominated (54.1%), followed by hypothermic (24.3%), and subnormothermic (21.6%). The majority of studies (87.0%) oxygenated their systems, most commonly with carbogen.

Conclusions

EVMP is a rapidly growing area of research. Leveraging EVMP in VCA can optimize VCA procedures and allow for expansion into replantation, flap salvage, and other areas of plastic surgery. Currently, VCA EVMP is achieved through a variety of approaches, but standardization is necessary to advance this technology and attain clinical translation.

Extensive head and neck skin cancers: Carcinologic surgery as a cornerstone of treatment

BACKGROUND AND OBJECTIVE

The prevalence of extensive skin cancers increases with the aging of the population. Surgical management is the gold standard of curative treatment while morbidity is not negligible. There are few data in the literature concerning extensive head and neck cutaneous cancers. The aim of this article is to report our experience of curative management of head and neck extensive skin cancers.

METHOD

In this single-center retrospective observational study, we report a series of 17 patients with extensive skin facial cancers treated by surgery between 2013 and 2022 in the maxillofacial surgery department of the Pitié-Salpêtrière Hospital. We collected clinical, therapeutic, histological, and carcinologic data.

RESULTS

The median age of the patients was 66 years [35-94]. There were 9 male and 8 women. Scalp (39 %) and cheek (22 %) locations were the most frequent ones. The most frequent histological types were squamous cell carcinoma (61 %) and basal cell carcinoma (17 %). Three patients received neoadjuvant treatment. The surgical treatment consisted mainly of carcinological resection followed by one-stage reconstruction by free flap for 5 (30 %) patients and without reconstruction for primary for 12 (70 %) patients, of whom 8 benefited from secondary reconstruction. Five patients received adjuvant radiotherapy or radio-chemotherapy. With a median follow-up of 40 months (2-72), the median overall survival was 40 months (12-72).

CONCLUSION

We know that extensive skin cancers of the face have a good prognosis on condition that the carcinological and reconstructive requirements are respected. Surgery remains the cornerstone of treatment while the improvement of adjuvant therapies, in particular the rise of immunotherapies or other targeted therapies, may allow to limit recurrences.

The Use of ECMO and Free-Fillet-Leg Flap for Complex Pelvic Reconstruction: A Case Report

Advanced sarcoma treatment in complex anatomical regions such as the pelvis poses significant surgical challenges. This report details a case involving a 35-year-old man with recurrent osteosarcoma of the left hemipelvis, who underwent a 16 h surgery for hemipelvectomy and reconstruction using a free tibia and fibula fillet leg flap. The procedure, necessitated by an infected, exposed iliac prosthesis, utilized extracorporeal membrane oxygenation (ECMO) for 8 h to maintain flap viability. The flap, incorporating tibia, fibula, and associated musculature was successfully inset and anastomosed to the left common iliac artery and vein, with additional venous anastomosis to the right iliac vein. Despite postoperative challenges such as venous stasis and intestinal ischemia, necessitating further surgical interventions, the patient achieved mobility with a walker at 3 months post-surgery, with stable conditions observed during a 2 years follow-up. ECMO enabled successful preservation and integration of the free fillet leg flap, demonstrating its potential in complex reconstructive surgeries. Specifically, ECMO may extend free flap viability in complex cases, offering new possibilities for challenging oncological and reconstructive surgeries.

The Future of Microsurgery: Vascularized Composite Allotransplantation and Engineering Vascularized Tissue

Background

Microsurgical techniques have revolutionized the field of reconstructive surgery and are the mainstay for complex soft tissue reconstruction. However, their limitations have promoted the development of viable alternatives. This article seeks to explore technologies that have the potential of revolutionizing microsurgical reconstruction as it is currently known, reflect on current and future vascularized composite allotransplantation (VCA) practices, as well as describe the basic science within emerging technologies and their potential translational applications.

Methods

A literature review was performed of the technologies that may represent the future of microsurgery: vascularized tissue engineering (VCA) and flap-specific tissue engineering.

Results

VCA has shown great promise and has already been employed in the clinical setting (especially in face and limb transplantation). Immunosuppression, logistics, cost, and regulatory pathways remain barriers to overcome to make it freely available. Vascularized and flap-specific tissue engineering remain a laboratory reality but have the potential to supersede VCA. The capability of creating an off-the-shelf free flap matching the required tissue, size, and shape is a significant advantage. However, these technologies are still at the early stage and require significant advancement before they can be translated into the clinical setting.

Conclusion

VCA, vascularized tissue engineering, and flap-specific bioengineering represent possible avenues for the evolution of current microsurgical techniques. The next decade will elucidate which of these three strategies will evolve into a tangible translational option and hopefully bring a paradigm shift of reconstructive surgery.

Machine Perfusion Deters Ischemia-Related Derangement of a Rodent Free Flap: Development of a Model

INTRODUCTION

Machine perfusion can enable isolated support of composite tissues, such as free flaps. The goal of perfusion in this setting is to preserve tissues prior to transplantation or provide transient support at the wound bed. This study aimed to establish a rodent model of machine perfusion in a fasciocutaneous-free flap to serve as an affordable testbed and determine the potential of the developed support protocol to deter ischemia-related metabolic derangement.

METHODS

Rat epigastric-free flaps were harvested and transferred to a closed circuit that provides circulatory and respiratory support. Whole rat blood was recirculated for 8 h, while adjusting the flow rate to maintain arterial-like perfusion pressures. Blood samples were collected during support. Extracellular tissue lactate and glucose levels were characterized with a microdialysis probe and compared with warm ischemic, cold ischemic, and anastomosed-free flap controls.

RESULTS

Maintenance of physiologic arterial pressures (85-100 mmHg) resulted in average pump flow rates of 360-430 μL/min. Blood-based measurements showed maintained glucose and oxygen consumption throughout machine perfusion. Average normalized lactate to glucose ratio for the perfused flaps was 5-32-fold lower than that for the warm ischemic flap controls during hours 2-8 (P < 0.05).

CONCLUSIONS

We developed a rat model of ex vivo machine perfusion of a fasciocutaneous-free flap with maintained stable flow and tissue metabolic activity for 8 h. This model can be used to assess critical elements of support in this setting as well as explore other novel therapies and technologies to improve free tissue transfer.

Towards Optimizing Sub-Normothermic Machine Perfusion in Fasciocutaneous Flaps: A Large Animal Study

Machine perfusion has developed rapidly since its first use in solid organ transplantation. Likewise, reconstructive surgery has kept pace, and ex vivo perfusion appears as a new trend in vascularized composite allotransplants preservation. In autologous reconstruction, fasciocutaneous flaps are now the gold standard due to their low morbidity (muscle sparing) and favorable functional and cosmetic results. However, failures still occasionally arise due to difficulties encountered with the vessels during free flap transfer. The development of machine perfusion procedures would make it possible to temporarily substitute or even avoid microsurgical anastomoses in certain complex cases. We performed oxygenated acellular sub-normothermic perfusions of fasciocutaneous flaps for 24 and 48 h in a porcine model and compared continuous and intermittent perfusion regimens. The monitored metrics included vascular resistance, edema, arteriovenous oxygen gas differentials, and metabolic parameters. A final histological assessment was performed. Porcine flaps which underwent successful oxygenated perfusion showed minimal or no signs of cell necrosis at the end of the perfusion. Intermittent perfusion allowed overall better results to be obtained at 24 h and extended perfusion duration. This work provides a strong foundation for further research and could lead to new and reliable reconstructive techniques.

A Treatment Approach for Carotid Blowout Syndrome and Soft Tissue Reconstruction after Radiotherapy in Patients with Oral Cancer: A Report of 2 Cases

BACKGROUND

This retrospective case series study aims to demonstrate a salvage technique for the treatment of carotid blow-out syndrome (CBS) in irradiated head and neck cancer patients with a vessel-depleted neck.

METHODS

Between October 2017 and October 2021, two patients (N = 2) with CBS were treated at our institution in a multidisciplinary approach together with the Department of Vascular Surgery. Patients were characterized based on diagnoses, treatment procedures, and the subsequent postoperative course.

RESULTS

Surgical emergency intervention was performed in both cases. The transition zone from the common carotid artery (CCA) to the internal carotid artery (ICA) was resected and reconstructed with a xenogic (case 1) or autogenic (case 2) interposition (end-to-end anastomosis). To allow reconstruction of the vascular defect, an additional autologous vein graft was anastomosed to the interposition graft in an end-to-side technique, allowing arterial anastomosis for a free microvascular flap without re-clamping of the ICA. Because of the intraoperative ICA reconstruction, none of the patients suffered a neurological deficit.

CONCLUSIONS

The techniques presented in the form of two case reports allow for acute bleeding control, cerebral perfusion, and the creation of a vascular anastomosis option in the vessel-depleted neck.

Microvascular reconstructions in oral and maxillofacial surgery - Results of a survey among oral and maxillofacial surgeons in Germany, Austria, and Switzerland

This study aimed to evaluate the use of microvascular free flaps (MFF) in oral and maxillofacial surgery (OMFS) in Germany, Austria, and Switzerland. A dynamic online questionnaire, using 42-46 questions, was sent to OMF surgeons based in hospitals in Germany, Austria, and Switzerland. The questionnaire was evaluated internally and externally. Aside from general information, data were collected on organizational aspects, approaches, MFF types and frequency, presurgical planning, intraoperative procedures, perioperative medications, flap monitoring, and patient management. Participants mostly performed 30-40 MFF each year (11/53). Most stated that the COVID-19 pandemic did influence MFF frequency (25/53) to varying extents. Radial forearm flap was most frequently used (37/53), followed by ALT (5/53), and fibula flap (5/53). Primary reconstruction was performed by most participants (35/48). Irradiated bony transplants were mostly used for implant placement after 12 months (23/48). Most participants (38/48) used reconstruction plates, followed by miniplates (36/48), PSI reconstruction (31/48), and PSI miniplates (10/48). Regarding the postoperative use of anticoagulants, low-molecular-weight (37/48) and unfractioned heparins (15/48) were widely used, most often for 3-7 days (26/48). Clinical evaluation was mostly preferred for flap monitoring (47/48), usually every 2 h (34/48), for at least 48 h (19/48). Strong heterogeneity in MFF reconstructions in OMFS was found, especially regarding the timepoints of reconstruction, types of osteosynthesis, and postoperative MFF management. These findings provide the chance to further compare the different treatment algorithms regarding relevant MFF aspects, such as postoperative management. This could create evidence-based treatment algorithms that will further improve the clinical outcomes in MFF reconstructions.

Aspirin, heparin and ischemia time in microvascular free flap surgery - their influence and an optimal anticoagulation protocol

BACKGROUND

Microvascular surgery has become a standardized technique for reconstruction of large tissue defects in Head and Neck Reconstructive Surgery. However, the main dreaded complications are thrombosis of blood vessels or major bleeding after surgery. Several different anticoagulation protocols have been established in the last decades to overcome these problems with varying degrees of success.

METHODS

Over a period of six years, a standardized anticoagulation protocol including acetylsalicylic acid (ASA) and unfractionated heparin (UFH) for direct intraoperative and postoperative administration was established, optimized and compared to a previously used non-standardized protocol. A total of 178 flap surgeries were included in the development and optimization process of the protocol.

RESULTS

ASA significantly increased the risk of complications when used for longer than 72 h (OR = 2.52; p = 0.002; 95% CI 1.39-4.59). Administration of UFH reduced flap loss (bolus: OR 0.68; p = 0.47; 95% CI 0.24-1.93; continuous UFH administration: OR = 0.61; p = 0.33; 95% CI 0.22-1.66), however doses greater than 500 IU/ h of UFH as continuous infusion increased the risk of complications. Reduction in ischemia time had no effect on the occurrence of complications.

CONCLUSION

Anticoagulation regimes in microvascular surgery can influence the postoperative complication rate. The optimal protocol should consist of a combination of ASA and UFH for the intraoperative and direct postoperative phase. Prolonged administration of ASA as well as doses &gt;500 IU/ h of UFH are to be avoided due to the increased complication rate.

Preoperative Peroneal Artery Perforator Mapping Using Indocyanine Green Angiography: A Prospective Clinical Trial

BACKGROUND

Perforator imaging is a prerequisite in preoperative planning of the peroneal perforator flap and the fibula skin island. Although reports indicate that indocyanine green angiography assessment method might be advantageous over conventional ultrasound-based techniques (i.e., Doppler and color duplex), in practice, clear evidence is lacking. Thus, a comparative assessment of the utility of indocyanine green angiography and ultrasound-based techniques in the identification of suitable lower leg skin perforators was performed.

METHODS

A prospective clinical cohort study with a series of 12 consecutive patients was conducted to assess indocyanine green angiography, Doppler ultrasound, and color duplex ultrasound techniques for preoperative perforator detection in the lower leg before free fibula flap harvest. Anatomical dissection served as a reference. Parameters measured were perforator spatial distance to the reference (precision), operative time expenditure, and ease of device usage for assessment/outcomes.

RESULTS

This study included 12 patients, with a total of 27 perforators. Exhibition of technique sensitivity and positive predictive values were as follows: indocyanine green angiography, 93 percent and 100 percent; Doppler ultrasound, 82 percent and 82 percent; and color duplex ultrasound, 89 percent and 86 percent, respectively. With regard to the indocyanine green angiography technique, the distance to the actual perforator location was significantly shorter, which aided detection and lesser time expenditure during operation.

CONCLUSIONS

The indocyanine green angiography technique proved to have high precision, sensitivity, positive predictive value, and easy-to-use capabilities because of its exceptional spatial and temporal information, compared to the conventional, ultrasound-based techniques. Therefore, indocyanine green angiography is superior for preoperative perforator imaging of the lateral lower leg.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, II.

Performance of microvascular anastomosis with a new robotic visualization system: proof of concept

Microvascular procedures require visual magnification of the surgical field, e.g. by a microscope. This can be accompanied by an unergonomic posture with musculoskeletal pain or long-term degenerative changes as the eye is bound to the ocular throughout the whole procedure. The presented study describes the advantages and drawbacks of a 3D exoscope camera system. The RoboticScope^®-system (BHS Technologies^®, Innsbruck, Austria) features a high-resolution 3D-camera that is placed over the surgical field and a head-mounted-display (HMD) that the camera pictures are transferred to. A motion sensor in the HMD allows for hands-free change of the exoscope position via head movements. For general evaluation of the system functions coronary artery anastomoses of ex-vivo pig hearts were performed. Second, the system was evaluated for anastomosis of a radial-forearm-free-flap in a clinical setting/in vivo. The system positioning was possible entirely hands-free using head movements. Camera control was intuitive; visualization of the operation site was adequate and independent from head or body position. Besides technical instructions of the providing company, there was no special surgical training of the surgeons or involved staff upfront performing the procedures necessary. An ergonomic assessment questionnaire showed a favorable ergonomic position in comparison to surgery with a microscope. The outcome of the operated patient was good. There were no intra- or postoperative complications. The exoscope facilitates a change of head and body position without losing focus of the operation site and an ergonomic working position. Repeated applications have to clarify if the system benefits in clinical routine.

Transplantation of a latissimus dorsi flap after nearly 6 hr of extracorporal perfusion: A case report

Prolonged ischemia of tissues inevitably leads to their necrosis. This is especially relevant in the case of transplantation or replantation. In such situations, reperfusion in a timely manner might not be possible due to transportation times or other unforeseen complications. Therefore, a readily available and simple method to oxygenate the tissue and thus widen the time frame to reperfusion seems desirable. Here, we present the case of extracorporal perfusion of a latissimus dorsi (LD) flap that was successfully transplanted after nearly 6 hr of ischemia. A 41-year-old patient suffered multiple injuries including complete severance of the popliteal artery requiring emergency bypass. After stabilization of the patient and subsequent debridement, a LD flap was performed for soft tissue coverage. However, there was an acute occlusion of the bypass during flap inset. To salvage the free flap, a one-way extracorporal perfusion of the flap with heparinized isotonic saline solution was performed for a total of 5 hr and 47 min. The flap survived with minimal tip necrosis. This case report describes the application of a simple extracorporal perfusion technique for salvage of a free flap over a prolonged ischemia time and discusses the relevant literature. Due to its ease and quickness of application as well as ubiquitous availability, it might serve as a valuable tool in cases of acute problems with the recipient vessels or other incidents where several hours of ischemia time are to be anticipated.

In vivo perfusion of free skin flaps using extracorporeal membrane oxygenation

BACKGROUND

The vessel-depleted, irradiated, and frozen neck, as well as severe atherosclerosis of recipient vessels represent challenging problems in free flap transfer. Extracorporeal free flap perfusion theoretically allows free flap reconstructions in the absence of local donor vessels, but is associated with a number of technical issues. In this study, a novel technique is presented using a commercially available system for extracorporeal membrane oxygenation (ECMO), modified for small blood volumes.

METHODS

After preclinical testing, an ECMO system certified for lung support was used to establish blood flow through the flap's artery with oxygenation, decarboxylation and warming of diluted packed blood cells. Venous blood was allowed to flow passively into a separate container. Perfusion was performed for 15 min at intervals of 4 h over 4-6 days.

RESULTS

Five patients with soft tissue defects requiring free flap reconstruction were included. Either primarily thinned anterolateral thigh (ALT) flaps (n = 3) or radial forearm flaps (n = 2) were used. We observed infection of the perfusate, with consequent subtotal flap loss, in one patient, complete epithelial loss in two patients, venous congestion in one case, and almost uneventful healing in the fifth patient. With conservative wound care and a split thickness skin graft in one case, stable wound coverage was achieved in all patients except one, who had secondary healing. None of the patients required a second flap for sufficient coverage.

CONCLUSIONS

The technique described is associated with the risks of infection, flap congestion, nutritive hypoperfusion, and consequent tissue loss. Nevertheless, stable defect closure seems to be achievable even in patients with depleted recipient vessels.

Extracorporeal Free Flap Perfusion Using Extracorporeal Membrane Oxygenation Device: An Experimental Model

Extracorporeal perfusion of organs has a wide range of clinical applications like prolonged vital storage of organs, isolated applications of drugs, bridging time to transplant, and free composite tissue transfer without anastomosis, but there are a limited number of experimental models on this topic.This study aimed to develop and evaluate a human extracorporeal free flap perfusion model using an extracorporeal membrane oxygenation device. Five patients undergoing esthetic abdominoplasty participated in this study. Deep inferior epigastric artery perforator flaps were obtained abdominoplasty flaps, which are normally medical waste, used in this model. Deep inferior epigastric artery perforator flaps were extracorporeally perfused with a mean of 6 days. The biochemical and pathological evaluations of the perfusions were discussed in the article.

Vascular architecture in free flaps: Analysis of vessel morphology and morphometry in murine free flaps

The aim of this study was to analyze the development of vascular architecture as well as vascular morphometry and morphology of anastomosed microvascular free flaps. Free pectoral skin flaps were raised in 25 rats and anastomosed to the femoral vessels in the groin region. CD31 immunohistology was performed after 3, 7 and 12 d (each 5 animals each) to analyze microvessel density (MVD), microvessel area (MVA) and microvessel size (MVS). Microvascular corrosion casting was performed after 7 and 12 d (5 animals each) to analyze vessel diameter (VD), intervascular distance (IVD), interbranching distance (IBD), and branching angle (BA). Further on, sprout and pillar density as hallmarks of sprouting and intussusceptive angiogenesis were analyzed. Pectoral skin isles from the contralateral side served as controls. A significantly increased MVD was found after 7 and 12 d (p each <0.001). MVA was significantly increased after 3, 7 and 12 d (p each <0.001) and a significantly increased MVS was analyzed after 3 and 7 d (p each <0.001). VD and IVD were significantly increased after 7 and 12 d (p each <0.001). For IBD, a significantly increase was measured after 7 d (p < 0.001). For IBA, sprout and pillar density, no significant differences were found (p each ≥0.05). Significant changes in the vascular architecture of free flaps after successful microvascular anastomosis were seen. Since there was no evidence for sprout and pillar formation within the free flaps, the increased MVD and flap revascularization might be induced by the receiving site.

Effects of Normovolemic Hemodilution on Survival of Skin Flaps: An Experimental Study

Background

The aim of this study was to investigate the effects of various ratios of hemodilution on the survival of McFarlane’s skin flaps.

Material/Methods

An experimental study was performed on 42 adult male Wistar rats (weighing 260 to 305 g) allocated to a control group without any volume loss and to 6 study groups with hemodilution ratios of 5%, 10%, 15%, 20%, 25%, and 30%. In all subjects, random-pattern McFarlane’s skin flaps were uniformly elevated and re-sutured to the donor sites. The amount of necrosis was evaluated on the 7^th day postoperatively and compared among the groups.

Results

The amounts of flap necrosis in the groups with 5%, 10%, 15%, and 20% hemodilution ratios were significantly lower than that of the control group (p<0.001). In the 25% and 30% hemodilution groups, although there was less necrosis than in the control group, the differences were not statistically significant. Hematocrit levels, which initially decreased in conjunction with the hemodilution ratios, returned to normal levels on the 7^th day after the operation.

Conclusions

Our results indicated that 20% or less of the total blood volume loss that may be compensated by the normovolemic hemodilution with dextran can improve flap survival.

Current insights into extracorporeal perfusion of free tissue flaps and extremities: a systematic review and data synthesis

BACKGROUND

Extracorporeal perfusion is a promising new technique for prolonged preservation of free flaps and extremities; however, uncertainties on perfusion settings and efficacy still exist. No overview of literature is currently available. This review systematically appraised available evidence comparing extracorporeal perfusion to static storage.

MATERIALS AND METHODS

An electronic systematic search was performed on June 12, 2016, in MEDLINE and EMBASE. Articles were included when evaluating the effect of extracorporeal perfusion of free flaps or extremities compared to that of a control group. Two independent researchers conducted the selection process, critical appraisal, and data extraction.

RESULTS

Of 3485 articles screened, 18 articles were included for further analyzation. One article studied discarded human tissue; others were studies conducted on rats, pigs, or dogs. Perfusion periods varied from 1 h to 10 d; eight articles also described replantation. Risk of bias was generally scored high; none of the articles was excluded based on these scores. Tissue vitality showed overall better results in the perfused groups, more pronounced when perfusing over 6 h. The development of edema was a broadly described side effect of perfusion.

CONCLUSIONS

Although tissue vitality outcomes seem to favor extracorporeal perfusion, this is difficult to objectify because of large heterogeneity and poor quality of the available evidence. Future research should focus on validating outcome measures, edema prevention, perfusion settings, and maximum perfusion time for safe replantation and be preferably performed on large animals to increase translation to clinical settings.