Evaluation of intra-operative abdominal wall perfusion in post-bariatric abdominal dermolipectomy.

OBJECTIVE: Abdominal dermolipectomy after massive weight loss has become a standard procedure. However the complication rates such as wound necrosis or secondary healing complications are still high. In this context ischaemia or inadequate micro-perfusion are known as triggers of wound healing complications. Little is known about the regional perfusion patterns before and after post-bariatric abdominal dermolipectomy. This study focuses on assessment of intraoperative micro-perfusion patterns of the abdominal tissue. METHODS: The perfusion of the abdominal wall flap was monitored intra-operatively in 17 patients with an average BMI of 29.2 ± 3.7 kg/m² after bariatric surgery. All patients underwent abdominal post-bariatric dermolipectomy after massive weight loss while applying the non-invasive O2C laser-spectrophotometer. The micro-perfusion parameters oxygen saturation (SO2), relative haemoglobin content (rHB) and relative blood flow (BF) were intra-operatively measured. RESULTS: The results of this study show that the part of the abdominal fat typically resected during dermolipectomy has the lowest SO2 before surgery. Furthermore, the results demonstrate that previously well oxygenated parts in the median line of the abdominal fat undergo a significant decrease in oxygen saturation upon mobilisation and subsequent suturing, while the caudal wound edges show an increase of micro-perfusion parameters. CONCLUSION: Data show that micro-perfusion is worst in the median line of the cranial wound edge and is significantly altered after mobilisation. In addition an intra-operative increase of micro-perfusion in the caudal part of the wound edge, especially in the mons pubis area, can be measured.

Expression of HIF-1α in ischemia and reperfusion in human microsurgical free muscle tissue transfer.

BACKGROUND: The aim of this study was to analyze the expression of hypoxia-inducible factor (HIF)-1α during ischemia and after reperfusion in muscle tissue in the context of microsurgical free muscle tissue transfer. METHODS: Ten patients with soft-tissue defects needing coverage with microsurgical free muscle flaps were included in this study. In all patients, the muscle samples were taken from free myocutaneous flaps. The first sample was taken before induction of ischemia in normoxia, another one was taken after 72 ± 11 minutes of ischemia, and the last one was taken 77 ± 22 minutes after reperfusion. The samples were analyzed using DNA microarray, real-time polymerase chain reaction, and immunohistochemistry. RESULTS: DNA microarray, real-time polymerase chain reaction, and immunohistochemistry did not provide evidence of differential expression of HIF-1α comparing ischemia and reperfusion to normoxia. However, DNA microarray showed an up-regulation of activating transcription factor-3 during ischemia and spermine N1-acetyltransferase-1 during ischemia and reperfusion. CONCLUSIONS: This study shows that ischemia and reperfusion induce alterations on the gene expression level in human muscle free flaps. Data from this study indicate that the expression of HIF-1α might not be affected but that other putative pathways of ischemic regulation might be of great interest. Finally, these findings correspond with the surgeon's clinical experience that the accepted times of ischemia, generally up to 90 minutes, are not sufficient to induce pathophysiologic processes, which can ultimately lead to flap loss.

Gene expression analysis of ischaemia and reperfusion in human microsurgical free muscle tissue transfer.

The aim of this study was to analyse various gene expression profiles of muscle tissue during normoxia, ischaemia and after reperfusion in human muscle free flaps, to gain an understanding of the occurring regulatory, inflammatory and apoptotic processes on a cellular and molecular basis. Eleven Caucasian patients with soft tissue defects needing coverage with microsurgical free muscle flaps were included in this study. In all patients, the muscle samples were taken from free myocutaneous flaps. The first sample was taken before induction of ischaemia in normoxia (I), another one after ischaemia (II), and the last one was taken after reperfusion (III). The samples were analysed using DNA-microarray, real-time-quantitative-PCR and immunohistochemistry. DNA-microarray analysis detected multiple, differentially regulated genes when comparing the different groups (I-III) with statistical significance. Comparing ischaemia (II) versus normoxia (I) educed 13 genes and comparing reperfusion (III) versus ischaemia (II) educed 19 genes. The comparison of reperfusion (III) versus normoxia (I) yielded 100 differentially regulated genes. Real-time-quantitative-PCR confirmed the results of the DNA-microarrays for a subset of four genes (CASP8, IL8, PLAUR and S100A8). This study shows that ischaemia and reperfusion induces alterations on the gene expression level in human muscle free flaps. Data may suggest that the four genes CASP8, IL8, PLAUR and S100A8 are of great importance in this context. We could not confirm the DNA-microarry and real-time-quantitative-PCR results on the protein level. Finally, these findings correspond with the surgeon's clinical experience that the accepted times of ischaemia, generally up to 90 min., are not sufficient to induce pathophysiological processes, which can ultimately lead to flap loss. When inflammatory and apoptotic proteins are expressed at high levels, flap damage might occur and flap loss is likely. The sole expression on mRNA level might explain why flap loss is unlikely.

Extracorporeal perfusion of free muscle flaps in a porcine model using a miniaturized perfusion system.

INTRODUCTION: The development of techniques in transplantation medicine--including various aspects--has made extraordinary progress within the past three decades. However, the transplantation of free tissue flaps with the common problem of limited ischemia time frames remains an area in which the understanding of mechanism during ischemia and reperfusion is still limited. Thus, similar to other organ transplantations, the prolongation of ischemic time and the possibility to perform an ex vivo perfusion is desirable. The purpose of this study was to create a closed and steady ex vivo perfusion system in order to analyze the possibility of using a miniaturized perfusion system for free muscle flaps that could also be clinically used for other solid organ transplantation. MATERIALS AND METHODS: The rectus abdominis muscles of six german pigs were used in the study. Each of these free muscle flaps was perfused for a period of 2 h using a pulsatile and closed pump perfusion system by cannulating the arterial and venous vessels of the flap pedicle. During the ex vivo perfusion parameters such as arterial and venous pressures were measured continuously. RESULTS: A total of six ex vivo, closed and steady perfusions have been successfully performed. The optimal arterial flow rate of ex vivo perfusion of rectus abdominis muscle flaps was evaluated to be 10 ml/min. The constant measurement of arterial (46 ± 13 mmHg) and venous (-1 ± 1 mmHg) pressure in this ex vivo setting showed steady parameters during a period for up to 2 h. CONCLUSION: The data of this study indicate that the ex vivo perfusion of free muscle flaps is technically feasible and a closed and steady circulation is manageable for a period of up to 2 h.

Wide topical negative pressure wound dressing treatment for patients undergoing abdominal dermolipectomy following massive weight loss.

Postbariatric plastic surgery is considered to be a high-risk procedure, which entails such frequent minor complications as postoperative seroma, bleeding and wound dehiscence. These occur with a high incidence, especially, following postbariatric abdominal dermolipectomy. In order to reduce these complication rates, a new type of dressing with wide abdominal topical negative pressure (TNP) application was applied. We performed abdominal dermolipectomy in 23 obese patients. The average body mass index was 32.8 kg/m(2), and the median age of the patients was 42.9 years. Ten patients received conventional standard dressings (control group I), whereas the other 13 patients received a wide TNP dressing including the ventral and lateral trunk (negative pressure group II). Postoperative exudate volumes were collected, tallied and documented for each group separately until all drains could be removed. The conventionally treated control group (I) showed a significantly higher postoperative secretion volume compared with the negative pressure group (II). In addition, the average time to postoperative final drain removal was significantly lower in the negative pressure group (II) compared with the control group (I). The results indicate that widely applied external TNP wound dressing on the ventral and lateral trunk following postbariatric abdominal dermolipectomy leads to a significant reduction in exudate formation, enables early drain removal and thus, decreases length of hospitalization.

Standards and interdisciplinary treatment of boxing injuries of the head in professional boxing on the basis of an IBF World Championship Fight.

BACKGROUND: Boxing injuries are well known in hobby boxing as well as in professional boxing. Especially in professional boxing it is of great importance to implement and follow prevention-, diagnosis- and therapy-standards in order to prevent or at least to minimize injuries of the athlete. The utmost aim would be to establish international prevention-, diagnosis- and therapy-standards for boxing injuries in professional boxing. However, this aim is on a short run unrealistic, as there are too many different professional boxing organisations with different regulations. A realistic short term aim would be to develop a national standard in order to unify the management and medical treatment of boxing injuries in professional boxing. CASE REPORT: We present the management and interdisciplinary treatment of a professional boxer with a bilateral open fracture of the mandible during a middle weight IBF World Championship Fight. On the basis of this case we want to present and discuss the possibilities of an interdisciplinary and successful medical treatment. CONCLUSIONS: In order to prevent or minimize boxing injuries of professional boxers, annual MRI-Scans of the head and neck have to be performed as prevention standard. Furthermore, neurocognitive tests must be performed on a regular basis. Boxing injuries in professional boxing need an interdisciplinary, unbiased and complex analysis directly at the boxing ring. The treatment of the injuries should be only performed in medical centres and thus under constant parameters. The needed qualifications must be learned in mandatory national licence courses of boxing physicians, referees and promoters.

Efficacy of Bone Source™ and Cementek™ in comparison with Endobon™ in critical size metaphyseal defects, using a minipig model.

INTRODUCTION: To examine and compare biocompatibility, osteocompatibility, rate of resorption, and remodelling dynamics of 2 calcium phosphate cements in comparison with a well-established hydroxyapatite ceramic. MATERIALS AND METHODS: In a randomised fashion, Bone Source™, Cementek™, and Endobon™ were implanted bilaterally into the proximal metaphyseal tibiae of 35 Göttinger minipigs in a direct right vs. left intra-individual comparison. Fluorescent labelling was used. Histological and morphometric evaluations were carried out at 6, 12, and 52 weeks. RESULTS: All bone substitutes showed good biocompatibility, bioactivity, and osteoconductivity. Endobon™ was not degraded over the follow-up period. Cementek™ was degraded constantly and significantly over the time intervals, whereas Bone Source™ was degraded mainly from the 6 week to 12 week interval. After 52 weeks, a significant difference of residual material within the defect zone was detected between all substitutes, with the highest resorption rate for Cementek™. Bone Source™ was least degraded. Defects filled with Endobon™ were characterised by a significantly continuous bony ingrowth over the time intervals. Bone formation within the defects filled with Cementek™ and Bone Source™ showed significant peaks 12 weeks after implantation. After 52 weeks, a significant difference in the amount of new bone within the defect area was detected, with the highest levels for Endobon™, followed by Cementek™. CONCLUSION: After 1 year a restitution ad integrum could not be observed in any treatment group. The ceramic Endobon™ showed the expected response histologically. Based on its porosity it excelled in osteoconductivity. Concerning the calcium phosphate cements, a thorough osseous incorporation seemed to inhibit further degradation of both bone substitute materials.

The efficacy of Biobon and Ostim within metaphyseal defects using the Göttinger Minipig.

INTRODUCTION: To compare bio, osteocompatibility, rate of resorption and remodeling dynamics of two clinically used bone substitutes. MATERIALS AND METHODS: In a randomized fashion Biobon and Ostim were implanted bilaterally into the proximal metaphyseal tibiae of 18 Göttinger Minipigs in a direct right versus left "intra-individual" comparison. Fluorescent labelling was used. Microradiographic, histological and morphometric evaluation was carried out at 6, 12 and 52 weeks. RESULTS: Both bone substitutes showed good biocompatibility, bioactivity and osteoconductivity. The degradation dynamics of both materials differed. Degradation of Ostim stopped after 6 weeks postoperatively, whereas Biobon was degraded slowly but evenly over the time intervals. Only at 6 weeks a significant (P < 0.05) difference in resorption rate was detected. Both Biobon and Ostim showed incomplete resorption after a year. CONCLUSION: After 1 year no "restitutio ad integrum" could be observed in either group. Similar to ceramics, a thorough osseous incorporation seemed to inhibit further degradation of both bone substitute materials.