Raymund Horch - Academia.edu (original) (raw)

Papers by Raymund Horch

Research paper thumbnail of Comparison of the Ramirez technique for the closure of large open myelomeningocele defects with alternative methods

Journal of plastic, reconstructive & aesthetic surgery : JPRAS, Jan 25, 2015

To compare the Ramirez technique for the operative closure of large open myelomeningocele defects... more To compare the Ramirez technique for the operative closure of large open myelomeningocele defects with conventional closure techniques in newborns. We hypothesized that the immediate surgical treatment with the Ramirez technique is superior to prior used operative techniques. From 2003 to 2010, 23 children (8 female, 15 male) underwent closure of large open myelomeningocele defects using the Ramirez technique (group A), while from 1993 to 2002, 23 children (6 female, 17 male) underwent conventional closure techniques (group B). All children were included in the retrospective analysis with a mean follow-up period of 3.4 years. Perioperative variables were similar in both groups (P = ns). There were no hospital deaths in both groups. The operation time was significantly higher in group A (228.7 ± 76.8 versus 157.8 ± 70.3 min, P = 0.003). Mean length of hospital stay was significantly lower in group A (30.7 ± 16.4 days versus 52.0 ± 38.5; P = 0.02). Postoperative complication rate was ...

Research paper thumbnail of Tissue engineer ing of cultured skin substitutes

Skin replacement has been a challenging task for surgeons ever since the introduction of skin gra... more Skin replacement has been a challenging task for surgeons ever since the introduction of skin grafts by Reverdin in 1871. Recently, skin grafting has evolved from the initial autograft and allograft preparations to biosynthetic and tissue-engineered living skin replacements. This has been fostered by the dramatically improved survival rates of major burns where the availability of autologous normal skin for grafting has become one of the limiting factors. The ideal properties of a temporary and a permanent skin substitute have been well defined. Tissue-engineered skin replacements: cultured autologous keratinocyte grafts, cultured allogeneic keratinocyte grafts, autologous/allogeneic composites, acellular biological matrices, and cellular matrices including such biological substances as fibrin sealant and various types of collagen, hyaluronic acid etc. have opened new horizons to deal with such massive skin loss. In extensive burns it has been shown that skin substitution with cultured grafts can be a life-saving measure where few alternatives exist. Future research will aim to create skin substitutes with cultured epidermis that under appropriate circumstances may provide a wound cover that could be just as durable and esthetically acceptable as conventional split-thickness skin grafts. Genetic manipulation may in addition enhance the performance of such cultured skin substitutes. If cell science, molecular biology, genetic engineering, material science and clinical expertise join their efforts to develop optimized cell culture techniques and synthetic or biological matrices then further technical advances might well lead to the production of almost skin like new tissue-engineered human skin products resembling natural human skin.

Research paper thumbnail of Is there a Rationale for Autologous Breast Reconstruction in Older Patients? A Retrospective Single Center Analysis of Quality of life, Complications and Comorbidities after DIEP or ms-TRAM Flap Using the BREAST-Q

The breast journal, Jan 24, 2015

Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle-sp... more Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap is a common method in the majority of patients after mastectomy. Because of an increased perioperative risk profile the benefit in older patients is questionable. To assess the postoperative quality of life and peri- and post-operative complications of older compared to younger patients is the aim of this retrospective study. In a retrospective analysis 39 older (i.e. >60 years) and 140 younger patients (i.e. <60 years) with autologous breast reconstruction in the Department of Plastic Surgery at the University Hospital of Erlangen-Nuernberg were surveyed at least 6 month postoperative using the BREAST-Q questionnaire. Correlations were generated between comorbidities and complications. Significant differences were observed regarding hospitalization, pre-existing diseases and the choice of DIEP versus ms-TRAM flaps. Para...

Research paper thumbnail of Severe mutilating injuries with complex macroamputations of the upper extremity – is it worth the effort?

World Journal of Emergency Surgery, 2015

Introduction: An amputation of the upper extremity and the following replantation is still one of... more Introduction: An amputation of the upper extremity and the following replantation is still one of the most challenging operations in the field of reconstructive surgery, especially in extremely severe cases of combined mutilating macroamputations including avulsion and multilevel injuries. Specialists agree that macroamputations with sharp wound edges are an absolute indication for replantation. However, there is no agreement in disastrous cases including avulsion and multilevel injuries. The outcome of the operation is depending on several factors, including the type of accident, age and pre-existing disease of the patient, as well as time of ischemia and appropriate physical therapy. Methods: Between January 1 st 2003 and December 31 st 2011 six patients underwent a macroreplantation with disastrous combined and complex injuries of the upper extremity in our department. We performed a follow up and evaluated the functional outcome of the upper extremity function using the DASH questionnaire (average follow up of 3.1 years). Results: The mean time of ischemia was 04:50 h (02:46 h-06:17 h). The mean time for the operation was 05:30 h (01:55 h-08:20 h). The mean operations needed per patient were 7 (2-16). The average hospital stay was 29d (16-59d).

Research paper thumbnail of LP14: HYPOXIA-INDUCIBLE FACTOR 1 (HIF-1A) EXPRESSION AS AN INDICATOR FOR HYPOXIA IN ENDOTHELIAL PROGENITOR CELLS (EPC) AND THE BIOARTIFICIAL TISSUE WITHIN THE ARTERIO-VENOUS (AV) LOOP RAT ISOLATION CHAMBER

Plastic and Reconstructive Surgery, 2010

Research paper thumbnail of In vitro cell response to Co-containing 1393 bioactive glass

Materials Science and Engineering: C, 2015

Cobalt ions are known to stimulate angiogenesis via inducing hypoxic conditions and hence are int... more Cobalt ions are known to stimulate angiogenesis via inducing hypoxic conditions and hence are interesting agents to be used in conjunction with bioactive glasses (BGs) in bone tissue engineering approaches. In this work we investigated in vitro cell biocompatibility of Co releasing 1393 BG composition (in wt.%: 53SiO2, 6Na2O, 12K2O, 5MgO, 20CaO, and 4P2O5) derived scaffolds with osteoblast-like cells (MG-63) and human dermal microvascular endothelial cells (hDMECs). Cell viability, cell number and cell morphology of osteoblast-like cells in contact with particulate glass and 3D scaffolds were assessed showing good biocompatibility of 1393 reference material and with 1wt.% CoO addition whereby 5wt.% of CoO in the glass showed cytotoxicity. Furthermore for 1393 with 1wt.% of CoO increased mitochondrial activity was measured. Similar observations were made with hDMECs: while 1393 and 1393 with 1wt.% CoO were biocompatible and the endothelial phenotype was retained, 5wt.% CoO containing BG showed cytotoxic effects after 1week of cell culture. In conclusion, 1wt.% Co containing BG was biocompatible with osteoblast like cells and endothelial cells and showed slightly stimulating effects on osteoblast-like cells whereas the addition of 5wt.% CoO seems to exceed the vital therapeutic ranges of Co ions being released in physiological fluids.

Research paper thumbnail of Assessing viability of extracorporeal preserved muscle transplants using external field stimulation: a novel tool to improve methods prolonging bridge-to-transplantation time

Scientific Reports, 2015

Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation.... more Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation. Perfusion protocols have been established for a variety of applications and proven to be superior to procedures used in clinical routine. Extracorporeal perfusion of muscle tissue though cumbersome is highly desirable since it is highly susceptible to ischemia-related damage. To show the efficacy of different perfusion protocols external field stimulation can be used to immediately visualize improvement or deterioration of the tissue during active and running perfusion protocols. This method has been used to show the superiority of extracorporeal perfusion using porcine rectus abdominis muscles perfused with heparinized saline solution. Perfused muscles showed statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. The combination of extracorporeal perfusion and external field stimulation may improve organ conservation research.

Research paper thumbnail of Intrapulmonary and Cutaneous Siliconomas after Silent Silicone Breast Implant Failure

Breast Journal, 2009

Since the implementation and use of silicone implants in breast surgery the risks are published a... more Since the implementation and use of silicone implants in breast surgery the risks are published and discussed. Especially, the incidence of late silicone implant rupture and its potential risk to induce local siliconomas are still under discussion and not sufficiently evaluated. So far literature data offer no information of intrapulmonal or peripheral located cutaneous siliconomas because of systemic migration of silicone after breast augmentation. In light of silicones checkered history, and given the large and growing number of women who choose to undergo breast augmentation surgery each year, the presented clinical findings in our study are likely to be of interest to medical professionals, producers, and consumers alike. We present six female patients with an average age of 55 (+/-5) years with bilateral rupture of silicone implants after breast augmentation for aesthetic reasons. The average time after operation was 18 (+/-6) years. In five patients, we identified peripheral located cutaneous siliconomas and one patient suffered from an intrapulmonal siliconoma. The diagnosis of bilateral rupture of the silicone implants was performed preoperatively by MRI-scans. All five peripheral cutaneous siliconomas and the intrapulmonal siliconoma were validated by histopathologic analysis. Six female patients suffered from bilateral rupture of silicone implants after breast augmentation. In five patients, we identified peripheral located cutaneous siliconomas which were surgically excised. One patient suffered from an intrapulmonal siliconoma. In this unique case a lobectomy with resection of the pulmonal segment 10 had to be performed. Clinical findings of peripheral cutaneous and even intrapulmonary siliconomas after bilateral rupture of silicone breast implants indicate a systemic hematogen or lymphatic pathway of silicone. These findings suggest that it is mandatory to inform the patient about the potential risk of local siliconomas, but also about the potential risk of peripheral cutaneous or even intrapulmonary siliconomas caused by systemic hematogen or lymphatic pathways of silicone after silent implant failure.

Research paper thumbnail of Median nerve compression can be detected by magnetic resonance imaging of the carpal tunnel

Clinically symptomatic carpal tunnel syndrome is not necessarily accompanied by impaired nerve co... more Clinically symptomatic carpal tunnel syndrome is not necessarily accompanied by impaired nerve conduction values. Surgical decompression, however, may immediately lead to complete and lasting relief of symptoms in these patients. Because minimally invasive techniques have reduced perioperative morbidity and vocational impairment related to operative decompression, the decision to decompress symptomatic patients (despite still unimpaired nerve conduction values) might be subject to discussion in the future. New diagnostic tools may be helpful in deciding which therapeutical options to choose. When the wrist is held either in flexion or in extension, the carpal tunnel pressure increases. To investigate the dynamic changes of the carpal tunnel shape during wrist motion, as well as the variations of space for the median nerve and its signal intensity in T2-weighting, magnetic resonance imaging (MRI) was performed on patients and healthy volunteers alike. Restitution and the persistence of pathological findings were assessed pre- and postoperatively. MRI (1.0 T) was performed on 20 wrists of patients with clinical symptoms of carpal tunnel syndrome (CTS) and pathological nerve conduction values. Healthy volunteers (20 wrists) were matched according to sex and age. MRI was performed in neutral, 45-degree extension, and 45-degree wrist flexion positions. T2-weighted signal intensity of the median nerve was measured in 18 patients pre- and postoperatively. The cross-sectional area of the carpal tunnel in patients with CTS tends to be smaller than that found in nonsymptomatic volunteers. The cross-sectional area of the carpal tunnel decreases during wrist flexion at the pisiform and hamate level. During wrist extension, the cross-sectional area of the carpal tunnel decreases at the level of the pisiform. During extension, it increases at the level of the hamate. The cross-sectional area of the median nerve showed an increase at the pisiform level (P &amp;amp;amp;amp;lt; 0.05), a flattening of the median nerve at the hamate hook level (P &amp;amp;amp;amp;lt; 0.05), and palmar deviation of the flexor retinaculum at the pisiform and hamate hook level (P &amp;amp;amp;amp;lt; 0.001). This was significantly greater in CTS patients than in individuals with normal wrists. Postoperatively, the distal flattening of the median nerve recovered in 94% of the cases reviewed. Although the signal intensity of the median nerve on T2-weighted images decreased by 67%, the motor latency recovered in only 39% of the cases. The carpal tunnel was smaller in CTS patients than in healthy volunteers. During flexion and extension, the space available for the median nerve narrows. This may lead to potential median nerve compression. MRI is accurate and reliable for diagnosis and postoperative follow-up of carpal tunnel syndrome. In cases with obvious clinical symptoms and yet not measurably impaired median nerve conduction values, it may be helpful in making a decision for surgical decompression.

Research paper thumbnail of Comment on “Microsurgical Techniques Used to Construct the Vascularized and Neurotized Tissue Engineered Bone”

BioMed Research International, 2015

Research paper thumbnail of Intraoperative flap design using ICG monitoring of a conjoined fabricated anterolateral thigh/tensor fasciae latae perforator flap in a case of extensive soft tissue reconstruction at the lower extremity

Microsurgery, 2015

In this report, we present a case of the use of a conjoined fabricated free anterolateral thigh (... more In this report, we present a case of the use of a conjoined fabricated free anterolateral thigh (ALT)/tensor fascia latae (TFL) perforator flap for reconstruction of the lower extremity with intraoperative flap design using intraoperative indocyanine green (ICG) monitoring. The flap was used for reconstruction of a 16 cm × 28 cm sized defect of the lower leg in a 24-year-old man. The defect was caused by a third degree open fracture to the tibia. Upon dissection of the ALT perforators, ICG monitoring showed that both dominant ALT perforators did not yield a sufficient perforasome (∼16 cm × 17 cm) for the larger flap needed. An adjacent TFL perforator also supplied a large perforasome (∼15 cm × 11 cm), so a conjoined fabricated flap was harvested and transplanted to cover an extensive lower leg defect. The artery of the TFL perforator pedicle was being in-flap anastomosed to a side branch of the ALT pedicle. Postoperative course was uneventful and there were no complications. Length of follow-up was 6 months, aesthetic and functional outcome was good. The patient was very satisfied with the aesthetic outcome. Both legs were fully mobile after intensive physiotherapy for the reconstructed leg. The leg where the flap had been harvested showed full strength in knee joint flexion. This case could show that identification of the supplying vessels may be possible by ICG monitoring. © 2015 Wiley Periodicals, Inc. Microsurgery, 2015.

Research paper thumbnail of Principles of Wound Repair

Plastic and Reconstructive Surgery, 2010

Basic principles as reviewed in this chapter can be applied to any reconstructive problem, from t... more Basic principles as reviewed in this chapter can be applied to any reconstructive problem, from the most basic to the most complex, and help improve the overall aesthetic outcome of wound closure and scar formation. A thorough assessment of the reconstructive problem, careful consideration of the affected anatomic region and proper patient selection are essential in choosing the optimal therapeutic

Research paper thumbnail of Autologous serum improves bone formation in a primary stable silica-embedded nanohydroxyapatite bone substitute in combination with mesenchymal stem cells and rhBMP-2 in the sheep model

International Journal of Nanomedicine, 2014

Research paper thumbnail of Results of combined vascular reconstruction and free flap transfer for limb salvage in patients with critical limb ischemia

Journal of Vascular Surgery, 2015

Combined vascular reconstruction and free flap transfer has been established in centers as a feas... more Combined vascular reconstruction and free flap transfer has been established in centers as a feasible therapeutic option in cases with critical limb ischemia (CLI) and large tissue defects otherwise destined for major amputation. However, the number of patients treated with this combined approach is limited, and data regarding long-term follow-up and functional outcome are scarce. We therefore report our 10-year experience in free flap transplantation after vascular reconstruction as a last attempt for limb salvage, with special emphasis of complication rate, limb salvage, and postoperative mobility. CLI patients undergoing combined vascular reconstruction and consequent free flap transfer from 2003 to 2013 were retrospectively observed. Of 80 cases in total, patients with traumatic and oncologic indications were excluded; 33 (mean age, 66 years; range, 51-82 years) of these cases were performed for limb salvage and were included in this study. Long-term follow-up was possible in 32 of 33 patients (mean, 58 months; range, 2-126 months). Thirty-three patients were analyzed. We performed arterial revascularization with 9 arteriovenous loops, 23 bypass grafts (10 popliteal-pedal, 9 femoral-crural, and 4 femoral-popliteal), and 1 venous interposition graft. For defect coverage, tissue transfer was comprised of six different flap entities (10 latissimus dorsi, 2 gracilis, 1 anterior lateral thigh, 7 rectus abdominis, 11 radialis, and 2 greater omentum flaps). Complications occurred in 16 of 33 patients (49%). Early complications included eight acute occlusions of arterial reconstructions; major bleedings were seen in eight patients as well. There were two flap losses and one major amputation in the early postoperative period. No in-hospital deaths were observed. Late results revealed a limb salvage rate of 87% after 1 year and 83% after 5 years. Amputation-free survival was 87% after 1 year and 75% after 5 years. Overall survival was 100% and 87% after 1 year and 5 years, respectively. Follow-up showed 42% of patients with no limitations in ambulation, 54% with maintained preoperative ambulatory status, and one bedridden patient. The combined approach for limb salvage in CLI patients is associated with excellent results in limb salvage and functional outcome in patients who would otherwise be candidates for major amputation, despite an initially elevated complication rate. The option of combined revascularization with free tissue transfer should be evaluated in all mobile patients with CLI, large tissue defects, and exposed tendon or bone structures before major amputation. However, further studies are required to support these results.

Research paper thumbnail of Flow Increase Is Decisive to Initiate Angiogenesis in Veins Exposed to Altered Hemodynamics

PLOS ONE, 2015

Exposing a vein to altered hemodynamics by creating an arteriovenous (AV) shunt evokes considerab... more Exposing a vein to altered hemodynamics by creating an arteriovenous (AV) shunt evokes considerable vessel formation that may be of therapeutic potential. However, it is unclear whether the introduction of oscillatory flow and/or flow increase is decisive. To distinguish between these mechanical stimuli we grafted a femoral vein into the arterial flow pathway of the contralateral limb in rats creating an arterioarterial (AA) loop (n = 7). Alternatively, we connected the femoral artery and vein using the vein graft, whereby we created an AV-loop (n = 27). Vessel loops were embedded in a fibrin filled chamber and blood flow was measured by means of flow probes immediately after surgery (day 0) and 15 days after loop creation. On day 15, animals were sacrificed and angiogenesis was evaluated using μCT and histological analysis. Mean flow increased from 0.5 to 2.4 mL/min and was elevated throughout the cardiac cycle at day 0 in AV-loops whereas, as expected, it remained unchanged in AA-loops. Flow in AV-loops decreased with time, and was at day 15 not different from untreated femoral vessels or AA-loop grafts. Pulsatile flow oscillations were similar in AV-and AA-loops at day 0. The flow amplitude amounted to ~1.3 mL/min which was comparable to values in untreated arteries. Flow amplitude remained constant in AA-loops, whereas it decreased in AV-loops (day 15: 0.4 mL/min). A large number of newly formed vessels were present in AV-loops at day 15 arising from the grafted vein. In marked contrast, angiogenesis originating from the grafted vein was absent in AA-loops. We conclude that exposure to substantially increased flow is required to initiate angiogenesis in grafted veins, whereas selective enhancement of pulsatile flow is unable to do so. This suggests that indeed flow and most likely wall shear stress is decisive to initiate formation of vessels in this hemodynamically driven angiogenesis model.

Research paper thumbnail of Membrane cell grafts, fresh and frozen, to cover full thickness wounds in athymic nude mice

Biobrane, an adherent, flexible temporary wound dressing was incubated with cultured human kerati... more Biobrane, an adherent, flexible temporary wound dressing was incubated with cultured human keratinocytes. The cells adhered quickly, forming ”membrane-cell-grafts” (MCG). Some of the grafts were frozen and, after thawing, viability was verified with an XTT colorimetric assay. MCGs, fresh and cryopreserved, were transplanted on full thickness wounds created on athymic nude mice and resulted in a differentiated epithelium of human

Research paper thumbnail of Applied tissue engineering in the closure of severe burns and chronic wounds using cultured human autologous keratinocytes in a natural fibrin matrix

Whereas in severe burns cultured human epithelial cells may well serve as a life saving method, t... more Whereas in severe burns cultured human epithelial cells may well serve as a life saving method, the true value of tissue-engineered skin products in chronic wound care has yet to be clearly defined. Among other well-known clinical problems, the engraftment rate of commercially available multilayered &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;sheet grafts&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; has been shown to vary extremely. Adherence of transplanted cells to the wound bed--especially in the presence of potential wound contamination-- is one of the crucial aspects of this technique. Keratinocyte suspensions in a natural fibrin sealant matrix can potentially treat a variety of skin defects. In acute burn wounds, as well as in chronic wounds the clinical application of this type of tissue-engineered skin substitute demonstrates the capacity of cultured human autologous keratinocytes in a fibrin sealant matrix to adhere to wound beds, attach and spread over the wound resulting in reepithelialization of both acute and chronic wounds. In full thickness burns the combination of this new tool with allogenic dermis is a promising option to achieve complete dermal-epidermal reconstitution by means of tissue engineering and guided tissue repair. When transferring this technique into the treatment of chronic wounds we found an optimal preparation of such recipient wound beds to be crucial to the success. The additional application of continuous negative pressure (vacuum therapy) and preliminary chip skin grafting to optimally prepare the recipient site may be helpful tools to achieve such well-prepared and graftable surfaces. Prospective controlled comparative studies should be designed to further assess the clinical efficacy of this technique.

Research paper thumbnail of Unusual explosive growth of a squamous cell carcinoma of the scalp after electrical burn injury and subsequent coverage by sequential free flap vascular connection - A case report

Background: Squamous cell carcinomos may arise from chronic ulcerating wounds in scars, most comm... more Background: Squamous cell carcinomos may arise from chronic ulcerating wounds in scars, most commonly postburn scars. Tumour growth usually takes place over months to years. Localization on the scalp is a relatively rare condition.

Research paper thumbnail of Distal extremity reconstruction for limbs salvage in diabetic foot ulcers with pedal bypass, flap plasty and vacuum therapy | Distale extremitätenrekonstruktion mit pedalem bypass und lappenplastiken beim diabetischen fußsyndrom nach vakuumvorbehandlung

There are numerous factors resulting in tissue damage and foot ulcers in diabetic patients. Criti... more There are numerous factors resulting in tissue damage and foot ulcers in diabetic patients. Critical ischaemia should be routinely excluded and an examination of the limb perfusion must be done in all cases with clinical suspicion of reduced perfusion. Pedal bypass grafting procedures in combination with flap plasty techniques achieve good results in patients with non-healing diabetic ulcers. Timing of the procedure is essential to avoid progression of gangrene. Good results of pedal bypass grafts support an indication at an early stage. Vacuum assisted wound therapy and local wound surgery can be done first to prepare patients with septic foot lesions for two-staged procedures.

Research paper thumbnail of Intrinsic versus extrinsic vascularization in tissue engineering

... EXTRINSIC VASCULARIZATION IN TISSUE ENGINEERING 317 ... Upon explantation and afterIndia ink ... more ... EXTRINSIC VASCULARIZATION IN TISSUE ENGINEERING 317 ... Upon explantation and afterIndia ink perfusion, constructs with a patent vascular loop displayed dark coloration. Upon histology, the vessel-loop in another two constructs was found to be thrombosed. ...

Research paper thumbnail of Comparison of the Ramirez technique for the closure of large open myelomeningocele defects with alternative methods

Journal of plastic, reconstructive & aesthetic surgery : JPRAS, Jan 25, 2015

To compare the Ramirez technique for the operative closure of large open myelomeningocele defects... more To compare the Ramirez technique for the operative closure of large open myelomeningocele defects with conventional closure techniques in newborns. We hypothesized that the immediate surgical treatment with the Ramirez technique is superior to prior used operative techniques. From 2003 to 2010, 23 children (8 female, 15 male) underwent closure of large open myelomeningocele defects using the Ramirez technique (group A), while from 1993 to 2002, 23 children (6 female, 17 male) underwent conventional closure techniques (group B). All children were included in the retrospective analysis with a mean follow-up period of 3.4 years. Perioperative variables were similar in both groups (P = ns). There were no hospital deaths in both groups. The operation time was significantly higher in group A (228.7 ± 76.8 versus 157.8 ± 70.3 min, P = 0.003). Mean length of hospital stay was significantly lower in group A (30.7 ± 16.4 days versus 52.0 ± 38.5; P = 0.02). Postoperative complication rate was ...

Research paper thumbnail of Tissue engineer ing of cultured skin substitutes

Skin replacement has been a challenging task for surgeons ever since the introduction of skin gra... more Skin replacement has been a challenging task for surgeons ever since the introduction of skin grafts by Reverdin in 1871. Recently, skin grafting has evolved from the initial autograft and allograft preparations to biosynthetic and tissue-engineered living skin replacements. This has been fostered by the dramatically improved survival rates of major burns where the availability of autologous normal skin for grafting has become one of the limiting factors. The ideal properties of a temporary and a permanent skin substitute have been well defined. Tissue-engineered skin replacements: cultured autologous keratinocyte grafts, cultured allogeneic keratinocyte grafts, autologous/allogeneic composites, acellular biological matrices, and cellular matrices including such biological substances as fibrin sealant and various types of collagen, hyaluronic acid etc. have opened new horizons to deal with such massive skin loss. In extensive burns it has been shown that skin substitution with cultured grafts can be a life-saving measure where few alternatives exist. Future research will aim to create skin substitutes with cultured epidermis that under appropriate circumstances may provide a wound cover that could be just as durable and esthetically acceptable as conventional split-thickness skin grafts. Genetic manipulation may in addition enhance the performance of such cultured skin substitutes. If cell science, molecular biology, genetic engineering, material science and clinical expertise join their efforts to develop optimized cell culture techniques and synthetic or biological matrices then further technical advances might well lead to the production of almost skin like new tissue-engineered human skin products resembling natural human skin.

Research paper thumbnail of Is there a Rationale for Autologous Breast Reconstruction in Older Patients? A Retrospective Single Center Analysis of Quality of life, Complications and Comorbidities after DIEP or ms-TRAM Flap Using the BREAST-Q

The breast journal, Jan 24, 2015

Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle-sp... more Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap is a common method in the majority of patients after mastectomy. Because of an increased perioperative risk profile the benefit in older patients is questionable. To assess the postoperative quality of life and peri- and post-operative complications of older compared to younger patients is the aim of this retrospective study. In a retrospective analysis 39 older (i.e. >60 years) and 140 younger patients (i.e. <60 years) with autologous breast reconstruction in the Department of Plastic Surgery at the University Hospital of Erlangen-Nuernberg were surveyed at least 6 month postoperative using the BREAST-Q questionnaire. Correlations were generated between comorbidities and complications. Significant differences were observed regarding hospitalization, pre-existing diseases and the choice of DIEP versus ms-TRAM flaps. Para...

Research paper thumbnail of Severe mutilating injuries with complex macroamputations of the upper extremity – is it worth the effort?

World Journal of Emergency Surgery, 2015

Introduction: An amputation of the upper extremity and the following replantation is still one of... more Introduction: An amputation of the upper extremity and the following replantation is still one of the most challenging operations in the field of reconstructive surgery, especially in extremely severe cases of combined mutilating macroamputations including avulsion and multilevel injuries. Specialists agree that macroamputations with sharp wound edges are an absolute indication for replantation. However, there is no agreement in disastrous cases including avulsion and multilevel injuries. The outcome of the operation is depending on several factors, including the type of accident, age and pre-existing disease of the patient, as well as time of ischemia and appropriate physical therapy. Methods: Between January 1 st 2003 and December 31 st 2011 six patients underwent a macroreplantation with disastrous combined and complex injuries of the upper extremity in our department. We performed a follow up and evaluated the functional outcome of the upper extremity function using the DASH questionnaire (average follow up of 3.1 years). Results: The mean time of ischemia was 04:50 h (02:46 h-06:17 h). The mean time for the operation was 05:30 h (01:55 h-08:20 h). The mean operations needed per patient were 7 (2-16). The average hospital stay was 29d (16-59d).

Research paper thumbnail of LP14: HYPOXIA-INDUCIBLE FACTOR 1 (HIF-1A) EXPRESSION AS AN INDICATOR FOR HYPOXIA IN ENDOTHELIAL PROGENITOR CELLS (EPC) AND THE BIOARTIFICIAL TISSUE WITHIN THE ARTERIO-VENOUS (AV) LOOP RAT ISOLATION CHAMBER

Plastic and Reconstructive Surgery, 2010

Research paper thumbnail of In vitro cell response to Co-containing 1393 bioactive glass

Materials Science and Engineering: C, 2015

Cobalt ions are known to stimulate angiogenesis via inducing hypoxic conditions and hence are int... more Cobalt ions are known to stimulate angiogenesis via inducing hypoxic conditions and hence are interesting agents to be used in conjunction with bioactive glasses (BGs) in bone tissue engineering approaches. In this work we investigated in vitro cell biocompatibility of Co releasing 1393 BG composition (in wt.%: 53SiO2, 6Na2O, 12K2O, 5MgO, 20CaO, and 4P2O5) derived scaffolds with osteoblast-like cells (MG-63) and human dermal microvascular endothelial cells (hDMECs). Cell viability, cell number and cell morphology of osteoblast-like cells in contact with particulate glass and 3D scaffolds were assessed showing good biocompatibility of 1393 reference material and with 1wt.% CoO addition whereby 5wt.% of CoO in the glass showed cytotoxicity. Furthermore for 1393 with 1wt.% of CoO increased mitochondrial activity was measured. Similar observations were made with hDMECs: while 1393 and 1393 with 1wt.% CoO were biocompatible and the endothelial phenotype was retained, 5wt.% CoO containing BG showed cytotoxic effects after 1week of cell culture. In conclusion, 1wt.% Co containing BG was biocompatible with osteoblast like cells and endothelial cells and showed slightly stimulating effects on osteoblast-like cells whereas the addition of 5wt.% CoO seems to exceed the vital therapeutic ranges of Co ions being released in physiological fluids.

Research paper thumbnail of Assessing viability of extracorporeal preserved muscle transplants using external field stimulation: a novel tool to improve methods prolonging bridge-to-transplantation time

Scientific Reports, 2015

Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation.... more Preventing ischemia-related cell damage is a priority when preserving tissue for transplantation. Perfusion protocols have been established for a variety of applications and proven to be superior to procedures used in clinical routine. Extracorporeal perfusion of muscle tissue though cumbersome is highly desirable since it is highly susceptible to ischemia-related damage. To show the efficacy of different perfusion protocols external field stimulation can be used to immediately visualize improvement or deterioration of the tissue during active and running perfusion protocols. This method has been used to show the superiority of extracorporeal perfusion using porcine rectus abdominis muscles perfused with heparinized saline solution. Perfused muscles showed statistically significant higher ability to exert force compared to nonperfused ones. These findings can be confirmed using Annexin V as marker for cell damage, perfusion of muscle tissue limits damage significantly compared to nonperfused tissue. The combination of extracorporeal perfusion and external field stimulation may improve organ conservation research.

Research paper thumbnail of Intrapulmonary and Cutaneous Siliconomas after Silent Silicone Breast Implant Failure

Breast Journal, 2009

Since the implementation and use of silicone implants in breast surgery the risks are published a... more Since the implementation and use of silicone implants in breast surgery the risks are published and discussed. Especially, the incidence of late silicone implant rupture and its potential risk to induce local siliconomas are still under discussion and not sufficiently evaluated. So far literature data offer no information of intrapulmonal or peripheral located cutaneous siliconomas because of systemic migration of silicone after breast augmentation. In light of silicones checkered history, and given the large and growing number of women who choose to undergo breast augmentation surgery each year, the presented clinical findings in our study are likely to be of interest to medical professionals, producers, and consumers alike. We present six female patients with an average age of 55 (+/-5) years with bilateral rupture of silicone implants after breast augmentation for aesthetic reasons. The average time after operation was 18 (+/-6) years. In five patients, we identified peripheral located cutaneous siliconomas and one patient suffered from an intrapulmonal siliconoma. The diagnosis of bilateral rupture of the silicone implants was performed preoperatively by MRI-scans. All five peripheral cutaneous siliconomas and the intrapulmonal siliconoma were validated by histopathologic analysis. Six female patients suffered from bilateral rupture of silicone implants after breast augmentation. In five patients, we identified peripheral located cutaneous siliconomas which were surgically excised. One patient suffered from an intrapulmonal siliconoma. In this unique case a lobectomy with resection of the pulmonal segment 10 had to be performed. Clinical findings of peripheral cutaneous and even intrapulmonary siliconomas after bilateral rupture of silicone breast implants indicate a systemic hematogen or lymphatic pathway of silicone. These findings suggest that it is mandatory to inform the patient about the potential risk of local siliconomas, but also about the potential risk of peripheral cutaneous or even intrapulmonary siliconomas caused by systemic hematogen or lymphatic pathways of silicone after silent implant failure.

Research paper thumbnail of Median nerve compression can be detected by magnetic resonance imaging of the carpal tunnel

Clinically symptomatic carpal tunnel syndrome is not necessarily accompanied by impaired nerve co... more Clinically symptomatic carpal tunnel syndrome is not necessarily accompanied by impaired nerve conduction values. Surgical decompression, however, may immediately lead to complete and lasting relief of symptoms in these patients. Because minimally invasive techniques have reduced perioperative morbidity and vocational impairment related to operative decompression, the decision to decompress symptomatic patients (despite still unimpaired nerve conduction values) might be subject to discussion in the future. New diagnostic tools may be helpful in deciding which therapeutical options to choose. When the wrist is held either in flexion or in extension, the carpal tunnel pressure increases. To investigate the dynamic changes of the carpal tunnel shape during wrist motion, as well as the variations of space for the median nerve and its signal intensity in T2-weighting, magnetic resonance imaging (MRI) was performed on patients and healthy volunteers alike. Restitution and the persistence of pathological findings were assessed pre- and postoperatively. MRI (1.0 T) was performed on 20 wrists of patients with clinical symptoms of carpal tunnel syndrome (CTS) and pathological nerve conduction values. Healthy volunteers (20 wrists) were matched according to sex and age. MRI was performed in neutral, 45-degree extension, and 45-degree wrist flexion positions. T2-weighted signal intensity of the median nerve was measured in 18 patients pre- and postoperatively. The cross-sectional area of the carpal tunnel in patients with CTS tends to be smaller than that found in nonsymptomatic volunteers. The cross-sectional area of the carpal tunnel decreases during wrist flexion at the pisiform and hamate level. During wrist extension, the cross-sectional area of the carpal tunnel decreases at the level of the pisiform. During extension, it increases at the level of the hamate. The cross-sectional area of the median nerve showed an increase at the pisiform level (P &amp;amp;amp;amp;lt; 0.05), a flattening of the median nerve at the hamate hook level (P &amp;amp;amp;amp;lt; 0.05), and palmar deviation of the flexor retinaculum at the pisiform and hamate hook level (P &amp;amp;amp;amp;lt; 0.001). This was significantly greater in CTS patients than in individuals with normal wrists. Postoperatively, the distal flattening of the median nerve recovered in 94% of the cases reviewed. Although the signal intensity of the median nerve on T2-weighted images decreased by 67%, the motor latency recovered in only 39% of the cases. The carpal tunnel was smaller in CTS patients than in healthy volunteers. During flexion and extension, the space available for the median nerve narrows. This may lead to potential median nerve compression. MRI is accurate and reliable for diagnosis and postoperative follow-up of carpal tunnel syndrome. In cases with obvious clinical symptoms and yet not measurably impaired median nerve conduction values, it may be helpful in making a decision for surgical decompression.

Research paper thumbnail of Comment on “Microsurgical Techniques Used to Construct the Vascularized and Neurotized Tissue Engineered Bone”

BioMed Research International, 2015

Research paper thumbnail of Intraoperative flap design using ICG monitoring of a conjoined fabricated anterolateral thigh/tensor fasciae latae perforator flap in a case of extensive soft tissue reconstruction at the lower extremity

Microsurgery, 2015

In this report, we present a case of the use of a conjoined fabricated free anterolateral thigh (... more In this report, we present a case of the use of a conjoined fabricated free anterolateral thigh (ALT)/tensor fascia latae (TFL) perforator flap for reconstruction of the lower extremity with intraoperative flap design using intraoperative indocyanine green (ICG) monitoring. The flap was used for reconstruction of a 16 cm × 28 cm sized defect of the lower leg in a 24-year-old man. The defect was caused by a third degree open fracture to the tibia. Upon dissection of the ALT perforators, ICG monitoring showed that both dominant ALT perforators did not yield a sufficient perforasome (∼16 cm × 17 cm) for the larger flap needed. An adjacent TFL perforator also supplied a large perforasome (∼15 cm × 11 cm), so a conjoined fabricated flap was harvested and transplanted to cover an extensive lower leg defect. The artery of the TFL perforator pedicle was being in-flap anastomosed to a side branch of the ALT pedicle. Postoperative course was uneventful and there were no complications. Length of follow-up was 6 months, aesthetic and functional outcome was good. The patient was very satisfied with the aesthetic outcome. Both legs were fully mobile after intensive physiotherapy for the reconstructed leg. The leg where the flap had been harvested showed full strength in knee joint flexion. This case could show that identification of the supplying vessels may be possible by ICG monitoring. © 2015 Wiley Periodicals, Inc. Microsurgery, 2015.

Research paper thumbnail of Principles of Wound Repair

Plastic and Reconstructive Surgery, 2010

Basic principles as reviewed in this chapter can be applied to any reconstructive problem, from t... more Basic principles as reviewed in this chapter can be applied to any reconstructive problem, from the most basic to the most complex, and help improve the overall aesthetic outcome of wound closure and scar formation. A thorough assessment of the reconstructive problem, careful consideration of the affected anatomic region and proper patient selection are essential in choosing the optimal therapeutic

Research paper thumbnail of Autologous serum improves bone formation in a primary stable silica-embedded nanohydroxyapatite bone substitute in combination with mesenchymal stem cells and rhBMP-2 in the sheep model

International Journal of Nanomedicine, 2014

Research paper thumbnail of Results of combined vascular reconstruction and free flap transfer for limb salvage in patients with critical limb ischemia

Journal of Vascular Surgery, 2015

Combined vascular reconstruction and free flap transfer has been established in centers as a feas... more Combined vascular reconstruction and free flap transfer has been established in centers as a feasible therapeutic option in cases with critical limb ischemia (CLI) and large tissue defects otherwise destined for major amputation. However, the number of patients treated with this combined approach is limited, and data regarding long-term follow-up and functional outcome are scarce. We therefore report our 10-year experience in free flap transplantation after vascular reconstruction as a last attempt for limb salvage, with special emphasis of complication rate, limb salvage, and postoperative mobility. CLI patients undergoing combined vascular reconstruction and consequent free flap transfer from 2003 to 2013 were retrospectively observed. Of 80 cases in total, patients with traumatic and oncologic indications were excluded; 33 (mean age, 66 years; range, 51-82 years) of these cases were performed for limb salvage and were included in this study. Long-term follow-up was possible in 32 of 33 patients (mean, 58 months; range, 2-126 months). Thirty-three patients were analyzed. We performed arterial revascularization with 9 arteriovenous loops, 23 bypass grafts (10 popliteal-pedal, 9 femoral-crural, and 4 femoral-popliteal), and 1 venous interposition graft. For defect coverage, tissue transfer was comprised of six different flap entities (10 latissimus dorsi, 2 gracilis, 1 anterior lateral thigh, 7 rectus abdominis, 11 radialis, and 2 greater omentum flaps). Complications occurred in 16 of 33 patients (49%). Early complications included eight acute occlusions of arterial reconstructions; major bleedings were seen in eight patients as well. There were two flap losses and one major amputation in the early postoperative period. No in-hospital deaths were observed. Late results revealed a limb salvage rate of 87% after 1 year and 83% after 5 years. Amputation-free survival was 87% after 1 year and 75% after 5 years. Overall survival was 100% and 87% after 1 year and 5 years, respectively. Follow-up showed 42% of patients with no limitations in ambulation, 54% with maintained preoperative ambulatory status, and one bedridden patient. The combined approach for limb salvage in CLI patients is associated with excellent results in limb salvage and functional outcome in patients who would otherwise be candidates for major amputation, despite an initially elevated complication rate. The option of combined revascularization with free tissue transfer should be evaluated in all mobile patients with CLI, large tissue defects, and exposed tendon or bone structures before major amputation. However, further studies are required to support these results.

Research paper thumbnail of Flow Increase Is Decisive to Initiate Angiogenesis in Veins Exposed to Altered Hemodynamics

PLOS ONE, 2015

Exposing a vein to altered hemodynamics by creating an arteriovenous (AV) shunt evokes considerab... more Exposing a vein to altered hemodynamics by creating an arteriovenous (AV) shunt evokes considerable vessel formation that may be of therapeutic potential. However, it is unclear whether the introduction of oscillatory flow and/or flow increase is decisive. To distinguish between these mechanical stimuli we grafted a femoral vein into the arterial flow pathway of the contralateral limb in rats creating an arterioarterial (AA) loop (n = 7). Alternatively, we connected the femoral artery and vein using the vein graft, whereby we created an AV-loop (n = 27). Vessel loops were embedded in a fibrin filled chamber and blood flow was measured by means of flow probes immediately after surgery (day 0) and 15 days after loop creation. On day 15, animals were sacrificed and angiogenesis was evaluated using μCT and histological analysis. Mean flow increased from 0.5 to 2.4 mL/min and was elevated throughout the cardiac cycle at day 0 in AV-loops whereas, as expected, it remained unchanged in AA-loops. Flow in AV-loops decreased with time, and was at day 15 not different from untreated femoral vessels or AA-loop grafts. Pulsatile flow oscillations were similar in AV-and AA-loops at day 0. The flow amplitude amounted to ~1.3 mL/min which was comparable to values in untreated arteries. Flow amplitude remained constant in AA-loops, whereas it decreased in AV-loops (day 15: 0.4 mL/min). A large number of newly formed vessels were present in AV-loops at day 15 arising from the grafted vein. In marked contrast, angiogenesis originating from the grafted vein was absent in AA-loops. We conclude that exposure to substantially increased flow is required to initiate angiogenesis in grafted veins, whereas selective enhancement of pulsatile flow is unable to do so. This suggests that indeed flow and most likely wall shear stress is decisive to initiate formation of vessels in this hemodynamically driven angiogenesis model.

Research paper thumbnail of Membrane cell grafts, fresh and frozen, to cover full thickness wounds in athymic nude mice

Biobrane, an adherent, flexible temporary wound dressing was incubated with cultured human kerati... more Biobrane, an adherent, flexible temporary wound dressing was incubated with cultured human keratinocytes. The cells adhered quickly, forming ”membrane-cell-grafts” (MCG). Some of the grafts were frozen and, after thawing, viability was verified with an XTT colorimetric assay. MCGs, fresh and cryopreserved, were transplanted on full thickness wounds created on athymic nude mice and resulted in a differentiated epithelium of human

Research paper thumbnail of Applied tissue engineering in the closure of severe burns and chronic wounds using cultured human autologous keratinocytes in a natural fibrin matrix

Whereas in severe burns cultured human epithelial cells may well serve as a life saving method, t... more Whereas in severe burns cultured human epithelial cells may well serve as a life saving method, the true value of tissue-engineered skin products in chronic wound care has yet to be clearly defined. Among other well-known clinical problems, the engraftment rate of commercially available multilayered &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;sheet grafts&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; has been shown to vary extremely. Adherence of transplanted cells to the wound bed--especially in the presence of potential wound contamination-- is one of the crucial aspects of this technique. Keratinocyte suspensions in a natural fibrin sealant matrix can potentially treat a variety of skin defects. In acute burn wounds, as well as in chronic wounds the clinical application of this type of tissue-engineered skin substitute demonstrates the capacity of cultured human autologous keratinocytes in a fibrin sealant matrix to adhere to wound beds, attach and spread over the wound resulting in reepithelialization of both acute and chronic wounds. In full thickness burns the combination of this new tool with allogenic dermis is a promising option to achieve complete dermal-epidermal reconstitution by means of tissue engineering and guided tissue repair. When transferring this technique into the treatment of chronic wounds we found an optimal preparation of such recipient wound beds to be crucial to the success. The additional application of continuous negative pressure (vacuum therapy) and preliminary chip skin grafting to optimally prepare the recipient site may be helpful tools to achieve such well-prepared and graftable surfaces. Prospective controlled comparative studies should be designed to further assess the clinical efficacy of this technique.

Research paper thumbnail of Unusual explosive growth of a squamous cell carcinoma of the scalp after electrical burn injury and subsequent coverage by sequential free flap vascular connection - A case report

Background: Squamous cell carcinomos may arise from chronic ulcerating wounds in scars, most comm... more Background: Squamous cell carcinomos may arise from chronic ulcerating wounds in scars, most commonly postburn scars. Tumour growth usually takes place over months to years. Localization on the scalp is a relatively rare condition.

Research paper thumbnail of Distal extremity reconstruction for limbs salvage in diabetic foot ulcers with pedal bypass, flap plasty and vacuum therapy | Distale extremitätenrekonstruktion mit pedalem bypass und lappenplastiken beim diabetischen fußsyndrom nach vakuumvorbehandlung

There are numerous factors resulting in tissue damage and foot ulcers in diabetic patients. Criti... more There are numerous factors resulting in tissue damage and foot ulcers in diabetic patients. Critical ischaemia should be routinely excluded and an examination of the limb perfusion must be done in all cases with clinical suspicion of reduced perfusion. Pedal bypass grafting procedures in combination with flap plasty techniques achieve good results in patients with non-healing diabetic ulcers. Timing of the procedure is essential to avoid progression of gangrene. Good results of pedal bypass grafts support an indication at an early stage. Vacuum assisted wound therapy and local wound surgery can be done first to prepare patients with septic foot lesions for two-staged procedures.

Research paper thumbnail of Intrinsic versus extrinsic vascularization in tissue engineering

... EXTRINSIC VASCULARIZATION IN TISSUE ENGINEERING 317 ... Upon explantation and afterIndia ink ... more ... EXTRINSIC VASCULARIZATION IN TISSUE ENGINEERING 317 ... Upon explantation and afterIndia ink perfusion, constructs with a patent vascular loop displayed dark coloration. Upon histology, the vessel-loop in another two constructs was found to be thrombosed. ...