The value of postoperative anticoagulants to improve flap survival in the free radial forearm flap: a systematic review and retrospective multicentre analysis.

BACKGROUND: Free radial forearm flap (FRFF) reconstruction is a valuable technique in head and neck surgery, which allows closure of large defects while striving to maintain functionality. Anticoagulative drugs are often administered to improve flap survival, although evidence regarding effectiveness is lacking. OBJECTIVE OF REVIEW: To investigate the effectiveness of postoperative anticoagulants to improve survival of the FRFF in head and neck reconstruction. TYPE OF REVIEW: Systematic review and multicentre, individual patient data meta-analysis. SEARCH STRATEGY: MEDLINE, EMBASE, Web of Science and CINAHL were searched for synonyms of 'anticoagulants' and 'free flap reconstruction'. EVALUATION METHOD: Studies were critically appraised for directness of evidence and risk of bias. Authors of the highest quality publications were invited to submit their original data for meta-analysis. RESULTS: Five studies were of adequate quality, and data from four studies (80%) were available for meta-analysis, describing 759 FRFF procedures. Anticoagulants used were as follows: aspirin (12%), low molecular weight dextran (18.3%), unfractioned heparin (28.1%), low molecular weight heparin (49%) and prostaglandin-E1 (2.1%). Thirty-one per cent did not receive anticoagulants. Flap failure occurred in 40 of 759 patients (5.3%) On univariate analysis, use of unfractioned heparin was associated with a higher rate of flap failure. However, these regimens were often administered to patients who had revision surgery of the anastomosis. In multivariate logistic regression analysis, anticoagulant use was not associated with improved flap survival or flap-related complications. CONCLUSIONS: The studied anticoagulative drugs did not improve FRFF survival or lower the rate of flap-related complications. In addition, some anticoagulants may cause systemic complications.

Regulation of heme oxygenase 1 expression by miR-27b with stem cell therapy for liver regeneration in rats.

Adipose-derived mesenchymal stem cells (ASCs) have been considered to be attractive and readily available adult mesenchymal stem cells (MSCs) and are becoming increasingly popular for use in regenerating cell therapy. However, recent evidence attributed a fibrotic potential to MSCs which differentiated into myofibroblasts with highly increased α-smooth muscle actin (α-SMA) expression while transplanted into an injured/regenerating liver in mice. In this study, we studied the role of miR-27b in ASCs and their regenerative potential after partial liver resection in rats. ASCs transfected with control siRNA or miR-27b were intravenously injected into autologous rats undergoing 70% partial hepatectomy (PH). Our data showed that the regenerative capacities of ASCs with overexpressed miR-27b were significantly higher compared with control ASCs. However, the enhanced regeneration, hepatic differentiation, and suppressed liver inflammation, as well as fibrotic activity, were significantly reverted by ZnPP coadministration (heme oxygenase-1 [HO-1] inhibitor) indicating an important role of HO-1 in the regenerating and cytoprotective activities of miR-27b-transfected ASCs. We demonstrated that administration of autologous ASCs overexpressed with miR-27b enhances rapid and early liver regeneration and, importantly, preserves function after PH. The ASCs with miR-27b overexpression might offer a viable therapeutic option to facilitate rapid recovery after liver resection.

Dendritic cell therapy in composite tissue allotransplantation.

Dendritic cells (DCs) are bone marrow-derived, professional antigen-presenting cells, with inherent tolerogenic function. The ability of immature or maturation-resistant DCs to regulate alloantigen-specific T-cell responses and to promote tolerance induction has been well demonstrated in organ and bone marrow transplantation. Recent data suggest that DCs can also promote long-term survival of composite tissue allografts in the absence of continued immunosuppressive drug therapy.

Ras modulation of superoxide activates ERK-dependent fibronectin expression in diabetes-induced renal injuries.

Although previous studies have demonstrated that diabetic nephropathy is attributable to early extracellular matrix accumulation in glomerular mesangial cells, the molecular mechanism by which high glucose induces matrix protein deposition remains not fully elucidated. Rat mesangial cells pretreated with or without inhibitors were cultured in high-glucose or advanced glycation end product (AGE) conditions. Streptozotocin-induced diabetic rats were given superoxide dismutase (SOD)-conjugated propylene glycol to scavenge superoxide. Transforming growth factor (TGF)-beta1, fibronectin expression, Ras, ERK, p38, and c-Jun activation of glomerular mesangial cells or urinary albumin secretion were assessed. Superoxide, not nitric oxide or hydrogen peroxide, mediated high glucose- and AGE-induced TGF-beta1 and fibronectin expression. Pretreatment with diphenyliodonium, not allopurinol or rotenone, reduced high-glucose and AGE augmentation of superoxide synthesis and fibronection expression. High glucose and AGEs rapidly enhanced Ras activation and progressively increased cytosolic ERK and nuclear c-Jun activation. Inhibiting Ras by manumycin A reduced the stimulatory effects of high glucose and AGEs on superoxide and fibronectin expression. SOD or PD98059 pretreatment reduced high-glucose and AGE promotion of ERK and c-Jun activation. Exogenous SOD treatment in diabetic rats significantly attenuated diabetes induction of superoxide, urinary albumin excretion, 8-hydroxy-2'-deoxyguanosine, TGF-beta1, and fibronectin immunoreactivities in renal glomerular mesangial cells. Ras induction of superoxide activated ERK-dependent fibrosis-stimulatory factor and extracellular matrix gene transcription of mesangial cells. Reduction of oxidative stress by scavenging superoxide may provide an alternative strategy for controlling diabetes-induced early renal injury.

Temporal and spatial expression of bone morphogenetic proteins in extracorporeal shock wave-promoted healing of segmental defect.

Extracorporeal shock wave (ESW) is a noninvasive acoustic wave, which has recently been demonstrated to promote bone repair. The actual healing mechanism triggered by ESW has not yet been identified. Bone morphogenetic proteins (BMP) have been implicated as playing an important role in bone development and fracture healing. In this study, we aimed to examine the involvement of BMP-2, BMP-3, BMP-4, and BMP-7 expression in ESW promotion of fracture healing. Rats with a 5-mm segmental femoral defect were given ESW treatment using 500 impulses at 0.16 mJ/mm(2). Femurs and calluses were subjected to immunohistochemistry and RT-PCR assay 1, 2, 4, and 8 weeks after treatment. Histological observation demonstrated that fractured femurs received ESW treatment underwent intensive mesenchymal cell aggregation, hypertrophic chondrogenesis, and endochondral/intramembrane ossification, resulting in the healing of segmental defect. Aggregated mesenchymal cells at the defect, chondrocytes at the hypertrophic cartilage, and osteoblasts adjunct to newly formed woven bone showed intensive proliferating cell nuclear antigen expression. ESW treatment significantly promoted BMP-2, BMP-3, BMP-4, and BMP-7 mRNA expression of callus as determined by RT-PCR, and BMP immunoreactivity appeared throughout the bone regeneration period. Mesenchymal cells and immature chondrocytes showed intensive BMP-2, BMP-3, and BMP-4 immunoreactivity. BMP-7 expression was evident on osteoblasts located at endochondral ossification junction. Our findings suggest that BMP play an important role in signaling ESW-activated cell proliferation and bone regeneration of segmental defect.

Free anterolateral thigh flap for extremity reconstruction: clinical experience and functional assessment of donor site.

From August of 1995 through July of 1998, 38 free anterolateral thigh flaps were transferred to reconstruct soft-tissue defects. The overall success rate was 97 percent. Among 38 anterolateral thigh flaps, four were elevated as cutaneous flaps based on the septocutaneous perforators. The other 34 were harvested as myocutaneous flaps including a cuff of vastus lateralis muscle (15 to 40 cm3), either because of bulk requirements (33 cases) or because of the absence of a septocutaneous perforator (one case). However, vastus lateralis muscle is the largest compartment of the quadriceps, which is the prime extensor of the knee. Losing a portion of the vastus lateralis muscle may affect knee stability. Objective functional assessments of the donor sites were performed at least 6 months postoperatively in 20 patients who had a cuff of vastus lateralis muscle incorporated as part of the myocutaneous flap; assessments were made using a kinetic communicator machine. The isometric power test of the ratios of quadriceps muscle at 30 and 60 degrees of flexion between donor and normal thighs revealed no significant difference (p > 0.05). The isokinetic peak torque ratio of the quadriceps and hamstring muscles, including concentric and eccentric contraction tests, showed no significant difference (p > 0.05), except the concentric contraction test of the quadriceps muscle, which revealed mild weakness of the donor thigh (p < 0.05). In summary, the functional impairment of the donor thighs was minimal after free anterolateral thigh myocutaneous flap transfer.

Concomitant ipsilateral pedicled fibular transfer and free muscle flap for compound tibial defect reconstruction.

Three patients with compound injuries of the lower extremities were treated with pedicle fibular grafts and a free muscle flap concomitantly. There were 1 female and 2 male patients, all of whom sustained high-energy trauma in a motor vehicle accident. The bone defect of the tibia ranged from 8 to 12 cm. The size of the soft-tissue defect ranged from 24 x 15 cm to 28 x 15 cm. All patients underwent preoperative angiography to ensure the patency of the peroneal artery and to avoid its use by risking viability of the leg. All patients were treated with an antegrade-flow pedicle fibular graft. The fibular graft was inserted as a single strut in 2 patients and as a double-barrel strut in 1 patient. The pedicle of the free muscle flap was anastomosed to the distal runoff of the fibular bone flap. All free muscle flap transfers succeeded without complication. Bone scans performed on postoperative day 7 showed viability of transferred bone. The average time to radiological union was 9 months, and the average time to full weight bearing was 12 months. Screw loosening occurred in 2 patients and osteomyelitis was noted in another patient who was treated successfully with sequestrectomy and antibiotics. Indications for this technique are a large segmental bone defect with a huge soft-tissue defect, and patency of the peroneal artery and at least one other major artery. This method provides the advantages of one-stage reconstruction, avoidance of contralateral donor site morbidity, easy control of infection, and chance for early weight bearing. When selected carefully, this technique can be considered when one wants to avoid a two-stage, two free flap transfer.

Healing of untidy traumatic skin defect of the face by secondary intention.

BACKGROUND: Untidy facial skin defects manifest extensive soft tissue injury and contamination. Since modern surgical principles emphasize immediate wound closure, most surgeons should learn to convert an untidy wound to a tidy one and to reconstruct defects immediately if possible with the use of grafts and flaps. However, in some situations, healing by secondary intention remains advantageous. The purpose of this study is to reevaluate this traditional approach. METHODS: Twenty patients with untidy facial skin defects were treated conservatively over a 4-year period. The defects ranged from 2 x 2 cm2 to 6 x 4 cm2 in size. The depths of wounds were classified into partial-thickness in 9 patients, full-thickness in 7 patients, and deep defects in 4 patients. Each patient was instructed on wound care, which included daily cleaning with normal saline, followed by application of hydrocolloid occlusive dressing. Prophylactic antibiotics were not used. RESULTS: The mean follow-up period was 17 months. All wounds healed within 3 to 5 weeks. There was no wound infection. One patient developed a hypertrophic scar over the cheek, and received excision of the scar and resurfacing with full-thickness skin graft. Two patients had residual traumatic tattooing which was resolved by laser therapy. Two patients had hypopigmentation/hyperpigmentation problems. Most patients (18/20) were satisfied with both functional and cosmetic results. CONCLUSION: Conservative wound care with hydrocolloid occlusive dressing allows good healing by secondary intention for traumatic facial defects in selected patients.

Salvage of the distal foot using the distally based sural island flap.

The authors describe their additional experience with the distally based sural island flap for reconstruction of the whole foot, including the forefoot area in 8 patients. The flap is vascularized by the lowermost perforating branches of the peroneal artery. The skin flap can be elevated, based on the lesser saphenous vein and its accompanying arteries, in all parts of the sural region. This modification allows a farther reach of the flap for coverage of the distal foot and sole. All flaps, innervated by the lateral sural cutaneous nerves, were able to provide protective sensation in the distal soles. In 7 patients the flaps survived completely, and only 1 patient had partial necrosis of the flap. The advantage of this flap is its constant and reliable blood supply without sacrifice of the major artery. Elevation of the flap is simple and rapid. This flap is a versatile alternative that should be considered prior to a free flap transfer.

Reverse venous outflow of a free fibular osteocutaneous flap: a salvage procedure.

The authors report 2 patients with a massive bony defect of the tibia due to chronic osteomyelitis. They reconstructed the defect using a free vascularized fibular osteocutaneous flap. Unfortunately, venous insufficiency was diagnosed 24 hours postoperatively. The previous anastomosed veins were promptly explored. The peroneal veins of the vascularized fibular bone graft were noted to be full of thrombi. After thrombectomy, the vessels became very fragile and broke down easily. It was impossible to achieve normal antegrade venous outflow from the previous vein of the donor graft; however, they found that distal runoff of the peroneal vein achieved a reverse venous outflow from the donor graft. The great saphenous vein was dissected and reanastomosed to achieve adequate venous drainage. This procedure may offer an alternative treatment for a flap with venous insufficiency.

Microvascular prefabricated free skin flaps for esophageal reconstruction in difficult patients.

BACKGROUND: Reconstruction of the esophagus for complicated benign stricture or after resection of malignant lesion is still a challenge for surgeons. When abdominal viscera cannot be used, skin flaps are selected for esophageal reconstruction. However, skin flaps for esophageal reconstruction are notorious for leakage, and have not been widely accepted. Prefabrication before microvascular transfer to its final site can improve the result of esophageal reconstruction when skin flaps are used. METHODS: Eight patients with complicated corrosive esophagitis had been treated with prefabricated skin flaps for esophageal reconstruction. The procedures are described in detail. RESULTS: All patients healed well without leakage. The barium study showed smooth passage. There was no dysphasia or regurgitation after education. Pulmonary complication happened in only 1 patient. Revision for the distal anastomosis was required in 1 patient due to narrowing. When the skin tube is long, the patients need water (or soup) to facilitate swallowing and occasionally use their hand to help the food passage. This method has the following advantages: (1) healing of the long suture line before transfer to withstand the intestinal juice; (2) reliable viability in the distal part of the flap, especially when an extended length of the flap is required; (3) more length of stable tissue for two-layered, tension-free anastomosis at the junction of skin and gastrointestinal mucosa to prevent leakage; and (4) the flap can be placed in the substernal position to meet the aesthetic requirement of young patients. The disadvantage was the staged operations. However, after prefabrication the transfer becomes safe and free of leakage. The overall morbidity is minimal. CONCLUSIONS: In rare situations when skin flaps are used for esophageal reconstruction, prefabrication provides advantages over conventional one-stage methods, although it needs additional procedures. This method is a combination of conventional technique and microsurgery.

Acute pulmonary edema after microsurgery: two case reports.

Postoperative management procedures after microsurgery are well-established. Usually, maintaining an adequate plasma volume will lower blood viscosity and will provide an adequate arterial inflow to keep the replantation or the flap viable in routine microsurgical procedures. But if the patient's underlying condition is neglected, disasterous complications may occur. The authors report two cases with severe postoperative complications after microsurgery. One patient was a 38-year-old male who suffered from diabetic foot ulcer and received a free muscle flap transfer. He developed acute pulmonary edema at day 6 postoperatively. The other patient was a 20-year-old pregnant woman at 31 weeks gestation who developed pulmonary edema on the POD 4 following microsurgical replantation of the thumb and index finger of her left hand. The complications were believed to be caused by fluid overload and neglect of the patients' underlying conditions. Knowledge of possible precipitating factors and careful monitoring of fluid should avoid acute pulmonary edema after microsurgery under certain unusual conditions.

Preoperative ultrasound Doppler study and clinical correlation of free posterior interosseous flap.

BACKGROUND: Conventional pedicled posterior interosseous flap has a relatively high rate of partial flap loss which may result in ultimate failure to provide coverage of this important structure. The goal of this study was to delineate the posterior interosseous flap as a reliable free tissue transfer. METHODS: From 1991 to 1995, 34 patients undergoing free posterior interosseous flap had preoperative Doppler mapping to determine the point of emergence of the skin perforators of the posterior interosseous artery. This finding was correlated intraoperatively with the number of perforators nourishing the posterior interosseous flap. The anatomic variations in the posterior interosseous artery were also identified. RESULTS: These results showed (1) the main skin perforator was consistent and reliable in all of the posterior interosseous flaps both in the preoperative Doppler evaluation and intraoperative findings; (2) the main skin perforator arose from the posterior interosseous artery, the ascending interosseous recurrent artery or the common interosseous artery in 26 cases (76%), 6 cases (17.6%) or 2 cases (5.9%) respectively; (3) the success rate with the use of the free posterior interosseous flap was 97% without any partial flap loss. CONCLUSION: It is concluded that the free posterior interosseous flap is a reliable flap with adequate arterial flow from constant main skin perforators and large antegrade venous drainage. A less reliable distally based pedicle flap can be changed into a reliable free flap, with the aid of preoperative non-invasive Doppler evaluation. This principle could be applied in the design of other "free skin perforator flaps".