An engineered muscle flap for reconstruction of large soft tissue defects.
ABSTRACT: Large soft tissue defects involve significant tissue loss, requiring surgical reconstruction. Autologous flaps are occasionally scant, demand prolonged transfer surgery, and induce donor site morbidity. The present work set out to fabricate an engineered muscle flap bearing its own functional vascular pedicle for repair of a large soft tissue defect in mice. Full-thickness abdominal wall defect was reconstructed using this engineered vascular muscle flap. A 3D engineered tissue constructed of a porous, biodegradable polymer scaffold embedded with endothelial cells, fibroblasts, and/or myoblasts was cultured in vitro and then implanted around the femoral artery and veins before being transferred, as an axial flap, with its vascular pedicle to reconstruct a full-thickness abdominal wall defect in the same mouse. Within 1 wk of implantation, scaffolds showed extensive functional vascular density and perfusion and anastomosis with host vessels. At 1 wk posttransfer, the engineered muscle flaps were highly vascularized, were well-integrated within the surrounding tissue, and featured sufficient mechanical strength to support the abdominal viscera. Thus, the described engineered muscle flap, equipped with an autologous vascular pedicle, constitutes an effective tool for reconstruction of large defects, thereby circumventing the need for both harvesting autologous flaps and postoperative scarification.
Project description:Using a perfusion decellularization protocol, we developed a decellularized skin/adipose tissue flap (DSAF) comprising extracellular matrix (ECM) and intact vasculature. Our DSAF had a dominant vascular pedicle, microcirculatory vascularity, and a sensory nerve network and retained three-dimensional (3D) nanofibrous structures well. DSAF, which was composed of collagen and laminin with well-preserved growth factors (e.g., vascular endothelial growth factor, basic fibroblast growth factor), was successfully repopulated with human adipose-derived stem cells (hASCs) and human umbilical vein endothelial cells (HUVECs), which integrated with DSAF and formed 3D aggregates and vessel-like structures in vitro. We used microsurgery techniques to re-anastomose the recellularized DSAF into nude rats. In vivo, the engineered flap construct underwent neovascularization and constructive remodeling, which was characterized by the predominant infiltration of M2 macrophages and significant adipose tissue formation at 3months postoperatively. Our results indicate that DSAF co-cultured with hASCs and HUVECs is a promising platform for vascularized soft tissue flap engineering. This platform is not limited by the flap size, as the entire construct can be immediately perfused by the recellularized vascular network following simple re-integration into the host using conventional microsurgical techniques.Significant soft tissue loss resulting from traumatic injury or tumor resection often requires surgical reconstruction using autologous soft tissue flaps. However, the limited availability of qualitative autologous flaps as well as the donor site morbidity significantly limits this approach. Engineered soft tissue flap grafts may offer a clinically relevant alternative to the autologous flap tissue. In this study, we engineered vascularized soft tissue free flap by using skin/adipose flap extracellular matrix scaffold (DSAF) in combination with multiple types of human cells. Following vascular reanastomosis in the recipient site, the engineered products successful regenerated large-scale fat tissue in vivo. This approach may provide a translatable platform for composite soft tissue free flap engineering for microsurgical reconstruction.
Project description:Insufficient neovascularization is associated with high levels of resorption and necrosis in autologous and engineered fat grafts. We tested the hypothesis that incorporating angiogenic growth factor into a scaffold-stem cell construct and implanting this construct around a vascular pedicle improves neovascularization and adipogenesis for engineering soft tissue flaps. Poly(lactic-co-glycolic-acid/polyethylene glycol (PLGA/PEG) microspheres containing vascular endothelial growth factor (VEGF) were impregnated into collagen-chitosan scaffolds seeded with human adipose-derived stem cells (hASCs). This setup was analyzed in vitro and then implanted into isolated chambers around a discrete vascular pedicle in nude rats. Engineered tissue samples within the chambers were harvested and analyzed for differences in vascularization and adipose tissue growth. In vitro testing showed that the collagen-chitosan scaffold provided a supportive environment for hASC integration and proliferation. PLGA/PEG microspheres with slow-release VEGF had no negative effect on cell survival in collagen-chitosan scaffolds. In vivo, the system resulted in a statistically significant increase in neovascularization that in turn led to a significant increase in adipose tissue persistence after 8 weeks versus control constructs. These data indicate that our model-hASCs integrated with a collagen-chitosan scaffold incorporated with VEGF-containing PLGA/PEG microspheres supported by a predominant vascular vessel inside a chamber-provides a promising, clinically translatable platform for engineering vascularized soft tissue flap. The engineered adipose tissue with a vascular pedicle could conceivably be transferred as a vascularized soft tissue pedicle flap or free flap to a recipient site for the repair of soft-tissue defects.
Project description:Traumatic soft tissue defects of the hand and upper extremities are common and may be challenging to the reconstructive surgeon. Several reconstructive procedures such as use of local, regional, distant, and free flaps have been described. This study aimed to report the techniques, outcomes, and complications of pedicle abdominal flaps in reconstructing hand and upper extremity defects. Methods:In this retrospective study, we included patients with different traumatic defects in the hand and upper extremities who underwent reconstruction by random pedicle abdominal flaps between 2002 and 2017 at Jordan University Hospital, Jordan. Data were collected and analyzed, and the variables studied included patient age and sex, etiology and size of the defect, complications, outcomes, and the need for further revision procedures. Appropriate statistical analysis was used to examine the potential factors affecting flap survival. Results:We included a total of 34 patients with a mean age of 22.2 years, ranging from 1 to 54 years. Finger degloving was seen in approximately half of the patients. Flap survival rate was 85.3%. A small area of defect was the only risk factor that significantly affected the flap failure rate. Conclusions:Thin pedicle abdominal flaps are a valid, affordable, and safe option in upper extremity traumatic defects, especially in situations where microsurgical techniques are unavailable or contraindicated. Extra care should be taken when the defect surface area is small.
Project description:: The deep inferior epigastric perforator (DIEP) flap is becoming the gold standard for breast reconstruction using autologous tissue. If there are scars in the abdomen from previous surgery, it is necessary to judge the indication for using this flap carefully. Particularly in cases with vertical midline scars, the blood flow supply to the zone II can be compromised. Even when patients have a median abdominal scar, it has been reported that the blood flow can extend beyond the scar and reach several centimeters to about half of zone II. We performed breast reconstruction using DIEP flaps for 2 patients with vertical midline scars in the lower abdomen. Indocyanine green angiography was conducted intraoperatively to confirm the vascular territory with a single pedicle before cutting off the flap. One patient showed fluorescence contrast on the contralateral side across the midline scar. However, the fluorescence contrast was absent across the midline scar in the other patient. Based on this result, we investigated the possible vascular territory of a single pedicled DIEP flap in patients with vertical midline abdominal scars. We suggest that successful blood supply to zone II of a single-pedicled DIEP flap in a patient with a vertical midline abdominal scar is related to the location of the perforator and the property of the tissue in the midline near the perforator. However, because it is difficult to predict the vascular territory of a single pedicle before surgery, intraoperative evaluation using such techniques such as indocyanine green fluorescence imaging is important.
Project description:Reconstruction of a complex defect around the knee, particularly involving a large soft-tissue defect or disruption of the extensor mechanism, is always a challenging problem. The purpose of this study was to introduce the use of a customized free perforator flap for complex soft-tissue reconstruction around the knee. Between June 2010 and March 2017, 16 patients underwent this procedure. The choice of flap design is based on the location of the wound, the required pedicle length, the missing tissue components and their volumes, and the risk of donor-site morbidity. The reconstruction was performed using anterolateral thigh perforator (ALTP) flaps in five cases, modified ALTP flaps in two cases, chimeric ALTP flaps in four cases, dual-skin paddle ALTP flaps in two cases, and chimeric thoracodorsal artery perforator flaps in two cases. Multiple perforator flaps and vascularized fascia lata were used in one case. All flaps survived postoperatively. No vascular congestion was observed, and partial necrosis was observed in only one case. Primary closure of the donor site was performed for all patients. At a mean follow-up time of 16.5 months, most cases showed satisfactory flap contours and acceptable functional outcomes. A free perforator flap is a reliable option for repairing complex soft-tissue defects in the knee region, especially when local and pedicled flaps are unavailable. Various flap designs allow for more individualized treatment approaches and can achieve better results.
Project description:<h4>Introduction and importance</h4> Lateral abdominal wall (LAW) defect presents as a rare and unique challenge to the reconstructive surgeons. <h4>Case presentation</h4> We report a huge recurrent right lateral abdominal DFSP with local invasion in a 35-year-old lady. After wide local excision, the reconstruction was done by using pedicled anterolateral thigh fasciocutaneous flap and gluteal fasciocutaneous rotational flap. <h4>Clinical discussion</h4> The goal of reconstruction of the lateral abdominal wall is similar to that of the anterior abdominal wall, namely to provide a static repair that will not attenuate and form a bulge or hernia over time. Anchoring a mesh to stable fixation points is expected to ensure structural integrity in the LAW defect. However, we selected fascial inset from our flaps which did not lead to hernia formation or a bulge following a 7-month postoperative review. In terms of soft tissue coverage, the pedicled anterolateral thigh fasciocutaneous flap and gluteal fasciocutaneous rotational flap were used. The standard free flap will require more complexity of works, especially if the recipient vessels for microsurgical reconstruction are remotely situated or sometimes not even available. <h4>Conclusion</h4> Huge full-thickness LAW defect following an oncological resection can be reconstructed with combination of simpler locoregional flaps which yield good functional and aesthetic outcome. Highlights • The lateral abdominal wall reconstruction is rarely discussed compared to the anterior abdominal wall reconstruction.• The goal of reconstruction is to provide a static repair that will not stretch or attenuate and form a bulge or hernia over time.• The full-thickness lateral abdominal wall defect was successfully reconstructed with pedicled anterolateral thigh fasciocutaneous flap and gluteal fasciocutaneous rotational flap.• Pedicled anterolateral thigh fasciocutaneous flap has many advantages namely a long pedicle, a wide arc of rotation, a large potential skin paddle, and a low donor site morbidity.
Project description:Covering soft tissue defects remains challenging for orthopaedic surgeons, especially those in resource-challenged facilities. Covering tissue defects follow a plan from simple to complex: primary closure, local flap, area flap, pedicle flap, and free flap. I will limit my discussion to the role of latter two. At the district-level hospital in Vietnam, pedicle flaps are generally more useful, so I will discuss free flaps only briefly. The choices of pedicle flaps include: kite flap, posterior interosseous flap, radial flap (Chinese flap), neurocutaneous flap, anterolateral thigh fasciocutaneous flap, gastrocnemius flap, sural flap, posterior leg flaps; we typically use a free flap with the latissimus dorsi. Soft tissue coverage with pedicle flaps has many advantages: reliability, relatively easy harvest, and good blood supply. Free flaps with microanastomosis have an important place in covering difficult medium- or large-sized soft tissue defects but also require more instruments and more highly trained surgeons.
Project description:Osteoradionecrosis is the most dreadful complication after head and neck irradiation. Orocutaneous fistula makes patients difficult to eat food. Fibular free flap is the choice of the flap for mandibular reconstruction. Osteocutaneous flap can reconstruct both hard and soft tissues simultaneously. This study was to investigate the success rate and results of the free fibular flap for osteoradionecrosis of the mandible and which side of the flap should be harvested for better reconstruction.A total of eight consecutive patients who underwent fibula reconstruction due to jaw necrosis from March 2008 to December 2015 were included in this study. Patients were classified according to stages, primary sites, radiation dose, survival, and quality of life.Five male and three female patients underwent operation. The mean age of the patients was 60.1 years old. Two male patients died of recurred disease of oral squamous cell carcinoma. The mean dose of radiation was 70.5 Gy. All fibular free flaps were survived. Five patients could eat normal diet after operation; however, three patients could eat only soft diet due to loss of teeth. Five patients reported no change of speech after operation, two reported worse speech ability, and one patient reported improved speech after operation. The ipsilateral side of the fibular flap was used when intraoral soft tissue defect with proximal side of the vascular pedicle is required. The contralateral side of the fibular flap was used when extraoral skin defect with proximal side of the vascular pedicle is required.Osteonecrosis of the jaw is hard to treat because of poor healing process and lack of vascularity. Free fibular flap is the choice of the surgery for jaw bone reconstruction and soft tissue fistula repair. The design and selection of the right or left fibular is dependent on the available vascular pedicle and soft tissue defect sites.
Project description:The blood supply pattern of the partial-thickness musculomucosal pedicle flaps is different from the traditional Abbe flap. The arterial blood supply and venous drainage are highly reliable during clinical practice.To describe the reconstruction of the philtrum in the cross-lip flap transfer using nasolabial muscle tension line group reconstruction.From January 1, 2014, through June 31, 2015, a total of 6 patients with upper lip defect were treated with philtrum reconstruction in the same stage of the split cross-lip flap transfer at the Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. These patients underwent reconstruction of the philtrum by nasolabial muscle tension line group reconstruction. The patients were compared with a randomly chosen group of 5 individuals without upper lip defects by measuring the 3-dimensional scans.In the patient group, the split flap was elevated from the posterior portion of the oris orbicularis muscle after the inferior labial arteries were divided. Then the partial-thickness flap was rotated 180° horizontally and inverted 180° upward to the upper lip defect. The philtrum was reconstructed using the nasolabial muscle tension line group reconstruction.Three-dimensional scans were performed from the 2-month to 28-month revisits.A total of 11 individuals were included in the study: 6 in the patient group (mean [SD] age, 17.0 [4.8] years; 2 [33.3%] female and 4 [66.7%] male) and 5 in the control group (mean [SD] age, 15.2 [6.0] years; 2 [40.0%] female and 3 [60.0%] male). In the patient group, 5 of 6 musculomucosal pedicle flaps were viable. A stable philtrum with philtral ridge and philtral dimple was reconstructed on the 5 flaps. The shape of the philtrum was natural according to the 3-dimensional scan measurement. One flap partially necrosed, and the scar retraction was severe postoperatively.The blood supply of the partial-thickness cross-lip flap was from the small vascular network of the lower lip. It is reliable to reconstruct a philtrum in this stage of flap transfer. A complete philtrum structure can be reconstructed by applying muscle tension on the flap.4.
Project description:Adequate soft tissue coverage is imperative after any interventions performed to maximize or preserve hand function. Although this can most simply be achieved by primary closure or a skin graft if possible, often a vascularized flap will be preferable, especially if a later secondary procedure is planned. Even moderately sized skin deficits of the upper extremity, and especially if involving the hand itself, can be better covered using a free tissue transfer. Many reasonable options in this regard are available. Muscle perforator flaps, as a relatively new variant of a fasciocutaneous flap, have unique attributes, including availability, diversity, accessibility, large size, and lengthy vascular pedicle, and since no muscle need be included, donor site function is preserved. As is shown here in a series of nine muscle perforator flaps in eight patients, these represent yet another alternative that should be considered if selection of a free flap is indicated to maintain hand function.