Afshin Rahmanian-Schwarz

A clinical evaluation of Biobrane® and Suprathel® in acute burns and reconstructive surgery

BACKGROUND In the treatment of superficial partial-thickness burns, various skin substitutes and temporary dressings offer potential advantages over traditional treatments. Nonetheless, the search for an ideal temporary skin substitute or biosynthetic wound dressing is still a continuous quest. This research aimed to provide objective data on the long-term outcome of Biobrane(®) and Suprathel(®). METHODS Eight months after the initial burn treatment of Biobrane(®) and Suprathel(®), skin elasticity was measured objectively using a Cutometer(®) and the scarring process was quantified using the Vancouver Scar Scale (VSS). RESULTS The median healing time for patients treated with Biobrane(®) was up to 1.8 days shorter then the Suprathel(®) group. Regarding the Vancouver Scar Scale (VSS), neither the single parameter, nor the total score were significantly different in both groups. In comparison, the Biobrane(®) group demonstrated superior Cutometer(®) parameters in regards to maximal extension, elasticity, retraction and pliability. Despite higher levels of Biobrane(®) group, the differences in the viscoelastic analysis of both substitutes did not vary significantly. CONCLUSION Using both substitutes, we observed satisfying results in superficial partial-thickness burn treatment, without any significant differences. Since the treatment of burned patients is associated with high socioeconomic load, the cost factor should be one of the most important criteria in dermal substitute selection.

A novel option in negative pressure wound therapy (NPWT) for chronic and acute wound care

INTRODUCTION Negative pressure wound therapy (NPWT) has become a widely accepted technique in treatment of all kinds of wounds. After a long period of clinical application of the V.A.C.™ system (KCI Inc., San Antonio, Texas, USA) a number of options for delivery of NPWT are now commercially available. An urgent need exists for evidence demonstrating clinical efficacy of these new devices to support clinicians regarding their choice of NPWT. METHODS 42 patients with an acute or chronic wound were randomly assigned to either treatment by V.A.C.™ (group A) or therapy with an alternative newly available polyurethane foam-based NPWT system (RENASYS GO™ - F/P, Smith & Nephew GmbH) (group B). In both groups NPWT was applied after surgical debridement to prepare the wound bed for skin grafting. After skin grafting NPWT was applied additionally to secure skin grafts and improve grafts survival. Primary outcome measures were the time to complete healing (days) and duration of the NPWT application (days). Secondary outcome measures were the number of dressing changes and reported complications. In addition, we evaluated the cost-benefit in the clinical implementation. RESULTS There were no significant differences comparing the investigated parameters between both groups. Especially average time to complete healing and average time NPWT was applied did not differ (p>0.05). No complications occurred in either group. By an almost identical supply agreement of both providers for our hospital RENASYS™ system appeared to be more cost-effective. CONCLUSION After a long period of preserving a monopoly market position of the V.A.C.™ system, a new comparable option was successfully tested in this preliminary study. The polyurethane foam-based NPWT system (RENASYS GO™ - F/P, Smith & Nephew GmbH) is an efficient and cost-effective alternative NPWT system, which we effectively implemented in therapeutic management of different kinds of wounds.

Evaluation of a non-invasive monitoring method for free flap breast reconstruction using laser doppler flowmetrie and tissue spectrophotometry

Despite advances in the monitoring of free flaps, there is still a demand for new technology to detect ischemic complications at an early stage. The aim of the present study was to evaluate the reliability of the O2C‐device in terms of detecting flap failure in commonly used perforator flaps for breast reconstruction.

In vivo biocompatibility and biodegradation of a novel thin and mechanically stable collagen scaffold.

The demand for scaffolds comprised of natural materials such as collagen has increased in recent years. However, many scaffolds rely on chemical or physical modifications in order to comply with the necessary requirements for biomedical engineering. We evaluated the in vivo biocompatibility and biodegradation of a novel, thin, mechanically stable, and chemically non-crosslinked collagen cell carrier (CCC). CCC was implanted subcutaneously into 25 adult Lewis rats and biopsies were taken on days 7, 14, 21, 42, and 84 after surgery. For histological analysis, paraffin sections of implanted skin were immunolabeled for CD68 and stained by hematoxylin-eosin and Masson-Goldners trichrome method. Macroscopic analysis of skin surface during wound healing process showed a normal physiological reaction. Biodegradation of CCC was completed 42 days after subcutaneous implantation. Histological evaluation revealed no evidence of encapsulation, scar formation, or long-term vascularization and inflammation. The collagen type I based biomaterial demonstrated a high in vivo biocompatibility, low irritability, complete resorption, and replacement by autologous tissue. The in vivo biocompatibility and degradation behavior encourage for further evaluation of CCC in surgical applications and regenerative medicine.

A quantitative analysis of the venous outflow of the deep inferior epigastric flap (DIEP) based on the perforator veins and the efficiency of superficial inferior epigastric vein (SIEV) supercharging.

BACKGROUND While the arterial perfusion of the anterior abdominal wall has been extensively described in the literature, little has been published on the venous drainage of the deep inferior epigastric flap (DIEP). The present study was performed to further clarify the venous drainage of DIEP flap, which remains a common vascular complication of this flap. METHODS We assessed the efficiency of venous outflow on 19 patients undergoing DIEP flap breast reconstruction, determining relative haemoglobin concentration (rHB) as an indicator of venous congestion. After the flap had been isolated on the perforator vessels, a selective clamping and declamping of the single lateral and medial perforator was performed and several measurements were carried out using a micro-lightguide spectrophotometer device (O2C: Oxygen to See; LEA Medizintechnik, Gießen, Germany). In addition, the efficacy of venous supercharging with ipsilateral and contralateral superficial inferior epigastric veins (SIEVs) was quantified. RESULTS For the sake of simplicity, we applied the classic perfusion zones of the lower abdomen as suggested by Hartrampf (1983). Regardless of lateral or medial DIEP perforator veins, zone IV showed the least venous outflow, while we observed the highest drainage in zone I. There was no significant difference between the venous drainage of the two immediately adjacent zones II and III. Supercharging with the contralateral SIEV showed a significantly better venous drainage in the contralateral zones II and IV, whereas the ipsilateral SIEV did not present any significant improvement in the venous drainage of any zone. CONCLUSION This study evaluated the characteristics of the venous outflow of the DIEP flap, based on the single perforator and the SIEVs. Our findings revealed that zones II and III have a similar venous drainage regardless of the perforator veins used. The supercharging of the contralateral SIEV leads to an improved venous outflow compared to the ipsilateral SIEV. This may support surgeons in minimising venous complications and may improve the degree of DIEP flap survival.

A composite osteomusculocutaneous free flap from the medial femoral condyle for reconstruction of complex defects.

This combined anatomic and clinical study illustrates the first experiences of an osteomyocutaneous flap from the medial femoral condyle for reconstruction of composite tissue defects. We analyzed the anatomic consistency and the vascular distribution of this flap and showed that muscle tissue can easily be added as a composite flap. Twenty-one flaps were harvested from fresh adult cadavers with careful identification of the origin and the course of the three different branches of the descending genicular artery. The corresponding skin areas and muscle portion were identified. The clinical application of this flap was described for closure of complex calcaneal defects. The cadaveric study presented a constant pedicle length and diameter of the arteries, combined with a constant venous drainage. Furthermore, the medial condyle provided a corticocancellous segment and separate vascularity for skin and muscle portions. In the case reports, satisfying results of bone union and soft tissue contouring were achieved. The medial femur condyle region is a reliable donor site for composite flaps, providing a good corticocancellous bony structure and a separate skin paddle, as well as a muscle portion. Its vascular distribution shows anatomic consistency. Despite long-term atrophy of muscle transplants, we believe the additional muscle tissue improves the reconstruction results and provides better soft tissue contouring.

Fibulo-scapho-lunate arthrodesis after resection of the distal radius for giant-cell tumor of the bone

Giant‐cell tumors of the distal radius are rare. They have a high‐risk of local recurrence and a risk of pulmonary metastasis. Curettage alone or combined with adjunctive agents is often associated with local recurrence.

A systematic review of the etiopathogenesis of Kienböck's disease and a critical appraisal of its recognition as an occupational disease related to hand-arm vibration

BackgroundWe systematically reviewed etiological factors of Kienböck’s disease (osteonecrosis of the lunate) discussed in the literature in order to examine the justification for including Kienböck’s disease (KD) in the European Listing of Occupational Diseases.MethodsWe searched the Ovid/Medline and the Cochrane Library for articles discussing the etiology of osteonecrosis of the lunate published since the first description of KD in 1910 and up until July 2012 in English, French or German. Literature was classified by the level of evidence presented, the etiopathological hypothesis discussed, and the authors conclusion about the role of the etiopathological hypothesis. The causal relationship between KD and hand-arm vibration was elucidated by the Bradford Hill criteria.ResultsA total of 220 references was found. Of the included 152 articles, 140 (92%) reached the evidence level IV (case series). The four most frequently discussed factors were negative ulnar variance (n=72; 47%), primary arterial ischemia of the lunate (n=63; 41%), trauma (n=63; 41%) and hand-arm vibration (n=53; 35%). The quality of the cohort studies on hand-arm vibration did not permit a meta-analysis to evaluate the strength of an association to KD. Evidence for the lack of consistency, plausibility and coherence of the 4 most frequently discussed etiopathologies was found. No evidence was found to support any of the nine Bradford Hill criteria for a causal relationship between KD and hand-arm vibration.ConclusionsA systematic review of 220 articles on the etiopathology of KD and the application of the Bradford Hill criteria does not provide sufficient scientific evidence to confirm or refute a causal relationship between KD and hand-arm vibration. This currently suggests that, KD does not comply with the criteria of the International Labour Organization determining occupational diseases. However, research with a higher level of evidence is required to further determine if hand-arm vibration is a risk factor for KD.

Development of an animal frostbite injury model using the Goettingen-Minipig

BACKGROUND A standardized reproducible animal model is desirable to gain a better understanding in the pathophysiology of frostbite injury and to develop novel therapies. Little has been studied about frostbite injury models. The depth and extent were not always being controllable and consistent. Therefore, we developed a frostbite injury model using the Göttingen Minipigs. METHODS 42 frostbite injuries were inflicted on the abdomen of seven minipigs using an aluminium bar (300g, circular with a radius of 1cm) frozen with liquid nitrogen to -196°C. The bar was applied for 1, 3, 6, 12, 30 and 60s. Five hours after injury biopsies were performed and evaluated by the presence of denatured collagen, blood vessels, follicular epithelial cells and mesenchymal cells. RESULTS A large spectrum of frostbite injuries was obtained ranging from superficial, superficial partial, deep partial to full thickness. The depth of injury in the sets of frostbites was highly consistent (Pearson correlation ranged from r=0.89 to 0.94). CONCLUSION We described a simple, inexpensive and safe swine frostbite model. The accurate reproducibility of the depth of the frostbite injuries allows researchers to accurately plan frostbite studies.

Reimbursement of burns by DRG in four European countries: An analysis

PURPOSE To analyze the German, Austrian, Italian and Spanish Diagnosis-Related Group (DRG)-systems regarding burns. METHODS We analyzed 78 cases of inpatients with burns which were processed by national DRG-groupers. DRGs were linked to thresholds concerning length of stay as well as reimbursement tables of the respective countries. MAIN FINDINGS Fifty-one % of cases showed higher reimbursement in Germany compared to Austria, 55% compared to Italy and 67% as against Spain. Total proceeds are highest in Austria with 1,577,000 €, followed by Italy with 1,569,000 €, Germany with 1,502,000 € and Spain with 902,596 €. No correlation was found between macroeconomic key figures and our data. CONCLUSIONS International comparison of reimbursement of burns by DRG could be a useful instrument for benchmarking while not depending solely on political decisions or country-specific cost data. For better comparability, hospital indices based on healthcare baskets should be discussed.