Matthias A. Reichenberger

Osteo-periosteal-cutaneous flaps of the medial femoral condyle: a valuable modification for selected clinical situations.

In situations of bony nonunions with poor skin coverage, transplantation of vascularized soft tissue in addition to bone graft is desirable. The use of the corticoperiosteal vascularized bone graft from the medial femoral condyle is well described. There are only anecdotal reports about its use as an osteocutaneous flap. This article presents our results with the use of an osteocutaneous flap from the medial femoral condyle. Between 2004 and 2009, four patients were treated with supracondylar osteocutaneous flaps for bony nonunions (tibia, ankle, calcaneous) with concomitant soft tissue defects. The size of the osseous grafts ranged from 3 x 5 to 6 x 5 cm. The supplying cutaneous vessels were an unnamed perforator of the descending genicular artery (two cases) or the saphenous branch (two cases). The first three cases healed primarily. Bony union was achieved between 32 and 170 days. The follow-up of the fourth case was too short to achieve a bony union. There was no flap loss or surgery-related complications at the donor site. The transfer of free combined vascularized corticoperiosteal-cutaneous flaps seems to be ideally suited for postradiation-induced fractures or chronic nonunions with poor chances of spontaneous healing and a concomitant small skin defect.

Extracorporeal shock wave treatment protects skin flaps against ischemia–reperfusion injury

Advances in the treatment of ischemia-reperfusion injury have created an opportunity for plastic surgeons to apply these treatments to flaps and implanted tissues. Using an extended inferior epigastric artery skin flap as a flap ischemia-reperfusion injury (IRI) model, we examined the capability of extracorporeal shock wave treatment (ESWT) to protect tissue against IRI in a rat flap model. Twenty-four rats were used and randomly divided into three groups (n=8 for each group). Group I was the sham group and did not undergo ischemic insult; rather, the flap was raised and immediately sutured back (non-ischemic control group). Group II (ischemia control) and Group III (ESWT) underwent 3h of ischemic insult. During reperfusion Group III was treated with ESWT and Group II was left untreated. Histological evaluation was made to investigate treatment induced tissue alterations. Survival areas were assessed at 5d postoperatively. Skin flap survival and perfusion improved significantly in the ischemic animals following ESWT (p<0.001, respectively). The tissue protecting effect of ESWT resulted in flap survival areas and perfusion data equal to non-ischemic, sham operated flaps. In line with the observation of better flap perfusion, tissue from ESWT-treated animals (Group III) revealed a significantly increased frequency of CD31-positive vessels compared to both the ischemic (Group II; p=0.003) and the non-ischemic, sham operated control (Group I; p<0.005) and an enhanced expression of pro-angiogenic genes. This was accompanied by a mild suppression of pro-inflammatory genes. Our study suggests that ESWT improves flap survival in IRI by promoting angiogenesis and inhibiting tissue inflammation. The study identifies ESWT as a low-cost and easy to use technique for surgical techniques that aim at reducing ischemia-reperfusion-induced tissue injury.

Comparison of Extracorporal Shock Wave Pretreatment to Classic Surgical Delay in a Random Pattern Skin Flap Model

Background: Extracorporal shock wave therapy has a significant positive effect on rescuing the ischemic zone of flap tissue if applied immediately after surgical intervention. The purpose of this study was to determine the potential preoperative effect of noninvasive extracorporal shock wave therapy to precondition flap tissue compared with the well-established surgical delay procedure. Methods: Thirty-two male Wistar rats were randomized into four groups, and an oversized, random-pattern flap was raised in each animal. In group D7, a surgical delay was carried out 1 week before full flap harvest. In group E7, the whole flap area was treated with extracorporal shock wave therapy to induce mechanical delay. Group E7D7 was treated preoperatively with a combination of surgical delay and extracorporal shock wave therapy. Group C constituted the control group, in which the skin flap was harvested without any prior intervention. Seven days after flap harvest, flap survival, perfusion, microvessel density, and vascular endothelial growth factor concentration were assessed. Results: Flap survival, perfusion, and microvessel density were significantly increased in the delay group (group D7) and the extracorporal shock wave therapy group (group E7) compared with the control group (group C). Combining both pretreatments (group E7D7) did not have a favorable cumulative effect. Vascular endothelial growth factor expression was not significantly increased in any group. Conclusions: Although not superior to surgical delay, the authors see many advantages of extracorporal shock wave therapy; it is noninvasive, easily applicable, less time- consuming, and less expensive. Thus, it may constitute an alternative procedure in clinical situations that warrant a noninvasive, fast, and easily applicable treatment.

Suprathel―Acetic Acid Matrix Versus Acticoat and Aquacel as an Antiseptic Dressing: An In Vitro Study

Background:The treatment of burn wounds is still a challenge regarding the management of antiseptic wound conditioning. Especially, in the United States, silver-containing dressings, such as Acticoat and Aquacel are frequently used. Because silver-containing dressings have well-known drawbacks such as an antimicrobial lack against Pseudomonas aeruginosa, we sought to develop an alternative dressing method. In previous studies, we could demonstrate the excellent antiseptic properties of acetic acid against common burn unit germs, and in another study, the feasibility and suitability of a Suprathel–acetic acid matrix as an antiseptic dressing. Materials and Methods:This study was designed to test the in vitro antimicrobial effect of a Suprathel–acetic acid matrix versus Acticoat and Aquacel. To cover the typical bacterial spectrum of a burn unit, the following Gram-negative and Gram-positive bacteria strains were tested: Escherichia coli, extended-spectrum beta-lactamase–positive Klebsiella pneumoniae, P. aeruginosa, Acinetobacter baumannii, Enterococcus faecalis, and methicillin-resistant Staphylococcus aureus. Results:The tests showed an excellent bactericidal effect of the Suprathel–acetic acid matrix particularly with problematic Gram-negative bacteria such as Proteus vulgaris, P. aeruginosa, and Acinetobacter baumannii. The efficiency was superior to that of Acicoat and Aquacel. Conclusions:Our results support the notion, that the Suprathel–acetic acid matrix has an excellent bactericidal effect and therefore seems to be suitable as a local antiseptic agent in the treatment of burn wounds.

Arteriovenous loops in microsurgical free tissue transfer in reconstruction of central sternal defects

OBJECTIVE In some patients with chest wall defects, free tissue transfer is indicated. Complications arise if multiple operations have left the trunk devoid of recipient vessels. In such patients, an arteriovenous loop between the cephalic vein and the thoracoacromial artery can be used. METHODS A review of all our patients who underwent chest wall reconstruction with a cephalic vein-thoracoacromial artery loop between 2000 and 2009 was performed (n = 29, 19 women and 10 men). The mean age was 64.9 years. Underlying causes were sternal osteomyelitis (n = 20), tumor (n = 4), and osteoradionecrosis (n = 5). All patients were in American Society of Anesthesiologists classes III and IV. Flap selection, intraoperative and postoperative complications, operative time, time of ventilatory support, mean hospital stay, and midterm survival were recorded. RESULTS Twenty-five patients received a tensor fascia lata flap, 2 a vertical rectus myocutaneuos flap, and 2 a deep inferior epigastric perforator flap. Mean duration of surgery was 6.8 hours (4.7-10.5 hours). Two transplanted tissue flaps died and/or had to be removed and 4 were revised successfully. Seven patients had wound complications such as infection or prolonged wound healing. Mean time for ventilator support was 93.6 hours (4-463 hours). The median intensive care unit time was 11 days and the overall hospital stay 27.4 days (11-102 days). One-year survival in the whole group was 69.8%. CONCLUSIONS The concept of arteriovenous loops allows creation of neovessels at the recipient site and has proven to be a superb tool to facilitate free tissue transfer or to provide an exit strategy in situations with unexpected vascular problems at the recipient site.

Preoperative shock wave therapy reduces ischemic necrosis in an epigastric skin flap model.

Extracorporeal shock wave therapy (ESWT) has recently been demonstrated to improve skin flap survival. In all these studies EWST was applied immediately after the surgical intervention. Thus, the purpose of this study was to determine the preoperative effect of ESWT as a noninvasive technique to precondition flap tissue in a rat epigastric skin flap model.EWST and control groups each contained 10 animals. ESWT was applied 7 days before the surgical intervention, whereas the control group received no treatment. Follow-up evaluation was performed on postoperative day 5. The mean area of flap necrosis, expressed as a percentage of the total flap area, was calculated. A significant reduction of the average flap necrosis area was observed in the ESWT group (27.2% ± 9.6%) compared with the control group (46.1% ± 7.9% (P < 0.05).In summary, this study indicates that preoperative ESWT may enhance skin flap survival in a rodent model.

Preoperative shock wave treatment enhances ischemic tissue survival, blood flow and angiogenesis in a rat skin flap model

INTRODUCTION Extracorporeal shock wave treatment (ESWT) has recently been shown to enhance skin flap survival. However, the bio-mechanisms operating during preoperative ESWT remain unclear. The aim of our study was to investigate whether preoperative ESWT can improve blood flow in ischemic skin flaps and to elucidate its possible mechanisms. METHODS 14 male-rats were randomized into two groups and an oversized ventral random-pattern flap was raised. Experimental group received extracorporeal shock-wave treatment (ESWT) with an energy of 500 mJ/mm(2) seven days prior to total flap elevation, while control group received no treatment prior to total flap elevation. Seven days postoperatively, surviving flap area, perfused flap area, microvessel density and VEGF concentration were measured. RESULTS Surviving flap area (59.43 ± 14.72 % to 42.71 ± 10.75 %, p = 0.026), perfused flap area (62.00 ± 8.58 % to 45.14 ± 10.50 %, p = 0.007), microvessel density (18.13 ± 5.11 to 11.09 ± 1.12, p = 0.016) and VEGF to total protein ratio (0.2107 ± 0.0935 to 0.0123 ± 0.0069, p = 0.008) were significantly elevated in the ESWT group. CONCLUSION Preoperative ESWT can improve skin flap survival through enhanced topical blood perfusion and neovascularization via elevation of angio-active factors.

Fibrin-Embedded Adipose Derived Stem Cells Enhance Skin Flap Survival

Surgical skin flaps are frequently used procedures in plastic and reconstructive surgery to cover acquired or congenital defects. Either partial or total skin flap loss is a common complication, as survival of the skin flaps is determined by tissue ischemia because of insufficient vascularity. To address this issue, a number of strategies have been described to enhance blood supply and to increase skin flap survival [1–3]. Among these, stem cell-based therapies play an increasing role, due to their capacity to self-renew and differentiate into a variety of specific cell lines. Especially adipose -derived stem cells (ADSCs)—therapies have raised tremendous interest in the field of soft tissue reconstruction as they offer distinct advantages over bone marrow-derived stem cells [4]. ADSCs can be easily harvested in a minimal invasive procedure, found in abundant quantities and have the ability to differentiate into osteoblasts, chondrocytes and adipocytes in controllable and reproducible manner [5–7]. With regard to plastic and reconstructive surgery perspectives, ADSCstherapy has recently been demonstrated to improve skin flap survival [8–14]. Further investigations documented a positive effect of rescuing ischemic skin flaps by increasing tissue perfusion, a significant rise of growth factors such as vascular endothelial growth factor (VEGF) as well as fibroblast growth factor (FGF) after ADSCtherapy in rodent model [8, 10–13]. However, in all these studies ADSCs were injected into the subcutaneous tissue which may result in an uncertain distribution of the ADSCs. Furthermore the purity of the applied stem cells was not clearly analyzed. In light of these recent results this study was designed to firstly isolate and cultivate rat adipose derived stem cells and secondly determine the potential of locally applied fibrinembedded ADSCs to enhance skin flap survival in an animal epigastric skin flap model.

ADSCs in a fibrin matrix enhance nerve regeneration after epineural suturing in a rat model

Due to their unique properties, adipose derived stem cells (ADSCs) obtain promising potential to enhance nerve regeneration. The aim of this study was to investigate if fibrin‐glue embedded ADSCs were a beneficial adjunct to primary coaptation in a rat sciatic nerve model. Materials and methods: Fifty male Lewis rats underwent sciatic nerve transection and subsequent epineural suture repair. The treatment group received ADSCs re‐suspended in fibrin glue, while the control group received fibrin glue only. After 7, 21, 35, and 63 days, analysis involved axon count, myelin sheath thickness as well as N‐ and G‐ratios. Additionally, muscle weight quotient (operated vs. non‐operated site of the same animal) was calculated and compared between treatment and control groups. For co‐detection of vital ADSCs, vessel walls, and Schwann cells, immunolabeling was performed with CM‐DiI, SMA, and S‐100 antibodies, respectively. Results: ADSCs led to a significant increase of myelinization at day 21 (0.508 ± 0.085 μm vs. 0.381 ± 0.044 μm, P = 0.025) and day 35 (0.872 ± 0.09 µm vs. 0.495 ± 0.078 µm; P = 0.01) after surgery. Axon count was significantly increased at day 21 (420 ± 119 vs. 129 ± 63; P = 0.003) and day 63 (284 ± 137 vs. 111 ± 26; P = 0.046) after surgery. N‐ and G‐ratios were significantly different compared with control indicating enhanced nerve regeneration due to ADSC treatment at each time point (P < 0.05). Muscle weight quotient was significantly higher in the treatment group compared with the control at day 21 (44.01% ± 6.16% vs. 35.03% ± 2.61%; P = 0.014) and day 63 (65.49% ± 2.81% vs. 58.79% ± 4.06%; P = 0.009) after surgery. Co‐detection of immunolabeled cells showed vital ADSCs at the neuronal repair site and in close proximity to intraneuronal vessels indicating active participation of ADSCs in the process of nerve regeneration and associated angiogenesis. Conclusion: ADSCs embedded in a fibrin matrix can significantly enhance regeneration of peripheral nerve injuries after primary coaptation.

Optimal Timing of Extracorporeal Shock Wave Treatment to Protect Ischemic Tissue

Enhancement of flap survival through extracorporeal shock wave treatment (ESWT) is a promising new technique; however, no attempt has been made to define the optimal time point and frequency of ESWT to optimize treatment with ESWT for ischemic indications. Twenty-eight male Wistar rats were randomized into 4 groups and an oversized, random-pattern flap was raised and reattached in place in each animal. ESWT was applied 7 days before (group E7) or immediately after the surgical intervention (group E0). The third group was treated with ESWT 7 days before and additionally immediately after the operation (group E7/0). The fourth group served as a control group and did not receive any ESWT (group C). Seven days after flap harvest the results of flap survival, perfusion, microvessel density, and vascular endothelial growth factor concentrations were assessed. Flap survival was significantly increased in all ESWT groups as compared with the control group. The groups (E7 and E0) that received ESWT pre- or postoperatively showed a significant increase in flap perfusion and microvessel density. Combined pre- and postoperative ESWT application (group E0/E7) did not demonstrate a cumulative effect in any evaluation. In this study, we were be able to prove the effectiveness of ESWT in the protection of ischemic tissue flaps. This study suggests that single postoperative application is the most efficacious protocol for clinical applications of ESWT in the treatment of ischemic tissue.