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Biomedical subjects

A D Bach

Publications and source records attributed to A D Bach.

18 recordsLinked to original sources
PubMed2006

[Vacuum assisted closure (V.A.C.) therapy is an essential tool for treatment of complex defect injuries of the upper extremity].

INTRODUCTION: Complex injuries of the upper extremity remain a therapeutic challenge. The prognosis of the damaged extremity is often limited by soft tissue defects. Vacuum Assisted Closure (V.A.C.) therapy facilitates temporary coverage of soft tissue defects prior to surgical reconstruction. METHODS: In a retrospective study all patients with complex defect injuries of the upper extremity that were treated by V.A.C. prior to reconstruction between August 2003 and September 2005 were analyzed. RESULTS: 7 patients (6 male, 1 female, 14-70 years) were included in the study. The patients suffered from subtotal upper arm (n = 1) and forearm (n = 1) amputation, complex multilevel amputation injury of the forearm (n = 1), slash wound of the forearm with skin defect and discontinuity of all volar structures (n = 1), complex open forearm fractures with skin and soft tissue defects (n = 2), and almost complete necrosis of the flexor compartment following distal radius and proximal ulnar fracture and compartment syndrome (n = 1). Stabile defect coverage was achieved in all patients following V.A.C. therapy by myocutaneous free flaps (n = 2), split thickness skin grafts (STSG) (n = 2), sequential secondary suture (n = 1), and STSG + secondary suture (n = 2). Wound conditions improved significantly under V.A.C. therapy. 5 patients reported pain relief following induction of V.A.C. therapy. Due to reduction of tissue oedema secondary suture was facilitated in 3 patients. DISCUSSION: V.A.C. therapy represents an essential tool for treatment of complex injuries of the upper extremity with extended soft tissue defects. Decreased frequency of dressing changes as well as reduced tissue oedema considerably improved patient's comfort. Posttraumatic compartment syndrome or skin necrosis, which are often associated with macro amputations of the upper extremity, are efficiently treated with V.A.C., and secondary sutures may be performed despite initial skin defects.

Adolescent↗
PubMed2006

[Application of V.A.C.-therapy during plastic surgical treatment of a bifocal Marjolin ulcer].

Marjolin ulcers are scar carcinomas most often found in old instable burn scars, the majority histopathologically characterized as squamous cell carcinomas. Surgical therapy includes radical excision and subsequent defect closure. We report about a 69 year old patient suffering from two scar carcinomas on the right cheek and right chest and abdomen due to an extensive infant burn injury. During a 2 stage procedure, both ulcers were initially excised and resulting soft tissue defects were closed temporarily by applying V.A.C. therapy. During a second procedure defect closure on the right cheek was achieved by using a free radial forearm flap following neck dissection. Additionally, the extensive defect including chest and abdominal wall as well as the flap donor site on the left forearm were covered with split thickness skin grafts and subsequently secured by applying V.A.C. therapy for 5 days. 13 days later, the patient was discharged from our clinic. All skin grafted areas as well as the free flap were stably healed. Our report demonstrates that the application of vacuum therapy is not only useful during temporary closure of large wound sites but also secures healing of large and critical areas grafted with split thickness skin grafts in tumour patients.

Abdominal Wall↗
PubMed2006

[Vacuum-assisted closure (V.A.C.) of disastrous wound conditions in Madelung disease].

INTRODUCTION: A 54 year old patient presented with a Madelung disease. Symmetrically fatty deposits were present on both upper arms, at the abdomen and both thighs. Dermatitis was seen in the axillary fold at the skin bearing surfaces. Shoulder movement was impaired. Liposuction of both upper arms has already been performed, but no significant improvement was obtained. METHODS AND RESULTS: We performed a dermolipectomy of both upper arms. Postoperatively the patient suffered from a severe wound dehiscence with fulminant wound infection and septic clinical condition. Because of the large wound surface ((1/3) of the upper arm circumference) anemia occurred and had to be treated with blood transfusions. Wound exsudation caused a general hypoproteinemia. Multiple surgical debridements were necessary in order to clean the wound from necrotic tissue and afterwards moist dressings were applied. Furthermore the patient received intravenous antibiotic treatment. After stabilisation of the general condition of the patient and the wound situation a polyvinyl sponge and a vacuum-sealing were applied and continuous suction was performed (125 mm Hg). This resulted in a significant improvement of the wound situation in regards to wound cleaning, induction of granulation tissue, diminished wound size, reduction of oedema and pain reduction. After four weeks of vacuum therapy defect coverage was possible and split thickness skin grafting was performed. The skin graft was attached to the wound using a vacuum-dressing. After removal of the vacuum dressing on the fifth day the skin graft has completely healed. DISCUSSION: Vacuum therapy is suitable for disastrous wound conditions in order to achieve a defect size reduction, pain reduction and create a clean wound with granulation tissue for further surgical defect coverage using skin grafts or flaps.

Arm↗
PubMed2006

[Use of vacuum therapy in a huge arterialized venous flap to reconstruct a complete avulsion of a thumb].

Arterialized venous flaps are normally raised from the anterior and distal third of the forearm by integration of a venous pathway. Basically, they are composed of skin, subcutaneous tissue, and subdermal venous plexus. Following transposition to the recipient site one vein is linked to a nourishing artery while the other veins are connected to one or more regional veins. The atypical blood perfusion and the delayed opening of intervenous shunts may result in edema, epidermolysis, or even some degree of skin necrosis that disappear during subsequent treatment. We report the salvage of an atypically raised oversized arterialized venous flap for total soft tissue reconstruction in a complete avulsion of a thumb. By applying V.A.C. therapy atypical perfusion and early intervenous shunt formation was treated successfully, resulting in stable healing and survival of the flap.

Aged, 80 and over↗
PubMed2006

[Reconstruction of tumor induced defects in head and neck surgery with individualized prefabricated three dimensional flaps with the use of continuous vacuum therapy].

Despite recent developments in oncologic head and neck surgery extensive tissue and functional defects following radical tumor resections remains a surgical challenge. Individually prefabricated free flaps to meet the needs of the functional defect can be generated with the help of continuous computer-assisted vacuum therapy. This accelerates the pre-fabrication of three-dimensional composite flaps and enhances therapeutic safety. Changes of the genuine structure of such flaps are induced by implantation of autologous or heterologous transplants alone or in combination with alloplastic materials as a supportive element. Application of vacuum therapy is useful to accelerate the process of pre-fabrication by the induction of angiogenesis. Besides this the continuous removal of wound exudate, possible seroma or haematoma and secondary compression of the different tissue layers improve the modelling of the three-dimensional construct. This article describes the technique of vacuum therapy for the pre-fabrication of three-dimensional pedicled or free flaps for reconstruction of defects after tumor resection in the head and neck area.

Absorbable Implants↗
PubMed2004

[Breast-reduction surgery--a long-term survey of indications and outcomes].

Between 1986 and 2003, breast-reduction surgery was performed in a total of 814 women. The indication was established on the basis of physical complaints, chronic back pain, stiff neck or recurrent intertrigo in the foldbeneath the breasts. A proportion of the patients were interviewed postoperatively using a questionnaire, to determine the impact of the operation on their quality of life. 91% of those surveyed reported a postoperative improvement in the perception of their own body, and 80% were satisfied with the reduced size of their breasts. In conclusion, in the hands of an experienced breast surgeon, breast-reduction surgery for the proper indication results in a reliable and safe diminishment in breast size and tightening of slack tissue, leading to a significant enhancement in the patient's quality of life.

Adolescent↗
PubMed2004

[Possiblities for breast reconstruction following cancer surgery].

Cancer of the breast is the most common malignant disease of women, and currently affects approximately 10% of all women. In the large majority of cases, mammary carcinoma can be treated without having to sacrifice the breast. In some 30% of the cases, however, amputation continues to be needed, in particular when a relatively large tumor presents, or when its removal with an adequate safety margin in a relatively small breast would result in appreciable deformation. Reconstruction of the breast is often an important psychological factor, since, as a visible organ, the breast is a determining feature of a woman's physical appearance and her effect on the opposite sex. The availability of various procedures and modern techniques of breast reconstruction make it possible to comply with the individual wishes of the woman concerned.

Breast Implantation↗
PubMed2004

[Indication and clinical results of buried skin grafting to treat problematic wounds].

In 1920 Braun described a technique of skin grafting particularly designed for areas where shearing forces, high pressure and extensive secretion cause repetitive loss of conventionally transplanted skin. During the last 10 years we successfully used this technique when impaired wound healing was encountered due to various reasons. Clinical examples of application and results are presented. By combining this technique with vacuum therapy, formation of granulation tissue can be accelerated, thereby resulting in successful transplantation of problematic and therapy resistant wounds.

Adult↗
PubMed2004

Y chromosome detection of three-dimensional tissue-engineered skeletal muscle constructs in a syngeneic rat animal model.

Surgical reconstruction of muscle tissue lost by trauma or tumor ablation is limited by the lack of availability of functional native tissue substitution. Moreover, so far most inherited or acquired muscle diseases are lacking sufficient treatment, because only few alternatives exist to provide functional restoration of lost muscle tissues. Engineering those tissues and transplantation into sites of dysfunction may be an alternative approach and may allow replacement of such damaged or failing skeletal muscle tissues. Techniques attempting reconstruction of some human tissues and organs (tissue engineering) have been introduced into clinical practice recently. One major problem that previous transplantation studies were facing is the ability of detection of transplanted cells after integration. Using the Y chromosome in situ hybridization technique in a syngeneic rat model allows transplantation of cell constructs orthotopically, without manipulation of the cells, with no rejection or immunosuppression being implied, but providing a nondilutable genetic marker to identify transplanted cells. The purpose of our study was to create functional skeletal muscle tissue in vivo using the transplantation of primary myoblasts precultivated within a three-dimensional (3D) fibrin matrix and to determine the fate of the transplanted cells using the Y chromosome detection technique. 3D myoblast cultures were established derived from male donor rats and after 7 days of cultivation we performed an orthotopic transplantation of 3D cell constructs into a created muscle defect within the gracilis muscle of syngeneic female rats. Anti-desmin immunostaining and Y chromosome in situ hybridization indicated the survival and integration of transplanted male myoblasts into the female recipient animal, thus demonstrating the feasibility of this approach in tissue engineering and the research of cell transplantation in general.

Animals↗
PubMed2003

Expression of Trisk 51, agrin and nicotinic-acetycholine receptor epsilon-subunit during muscle development in a novel three-dimensional muscle-neuronal co-culture system.

The purpose of our study was to create functional muscle tissue in vitro and to investigate the influence of organotypic neuronal slice cultures from rat spinal cord on the differentiation and function of primary rat myoblasts in a novel three-dimensional culture system. Three-dimensional muscle-neuronal cultures were established by co-cultivating primary rat skeletal muscle cells of newborn rats with organotypic slice cultures of the spinal cord prepared from isogenic rats in a fibrin matrix. These constructs were cultured for up to 4 weeks. Differentiation and fusion of the myoblasts to myofibers was evaluated by analyzing the expression pattern and localization of muscle- and neuron-specific markers. The fibrin matrix provided a suitable environment for three-dimensional myoblast culture. Co-culturing of organotypic spinal cord slices with myoblasts induced the formation of spontaneously contracting multinuclear and parallel-aligned myofibers. Pharmacological tests suggested the formation of neuromuscular junctions. The analysis of neural agrin expression and myogenic desmin, myogenin, MyoD, Trisk 51, and nicotinic-acetycholine receptor (nACh-receptor) epsilon-subunit expression revealed the differentiation of the myoblasts to myofibers. The presented novel three-dimensional co-culture system allows the in vitro investigation of myoblast differentiation and neuron-myoblast interaction. Our results suggest the existence of an alternative pathway for the maturation of the nAChR gamma-subunit to the epsilon-subunit without neural agrin activity.

Agrin↗
PubMed2003

Skin tissue engineering.

The coverage of extensive wounds with viable autologous keratinocytes remains the only option of treatment if autologous donor skin is not obtainable. There is evidence that proliferating keratinocytes, as suspended cells or as a single layer, are adequate for wound closure. Understanding keratinocyte-matrix interactions not only allows us to influence keratinocyte outgrowth, adhesion, and migration, but may also guide us to modify matrix molecules for enhancing keratinocyte take. Further approaches may include the generation of genetically manipulated keratinocytes, which allow the use of an off-the-shelf epidermal replacement. As surgeons, our goal is to help burn patients with the best quality of skin in the shortest time possible. As tissue engineers, we have not achieved the goal of a universal skin product. By continually reviewing the options and using them, we can at least use the proper material in the adequate situation. Because of the limited resources, the need for comparisons of clinical effectiveness and cost are ever more important. As anatomy and physiology of engineered skin substitutes improve, they will become more similar to native skin autografts. Improvement of skin substitutes will result from inclusion of additional cell types (eg, melanocytes) and from modifications of culture media and scaffolds. Skin-substitute materials may be able to stimulate regeneration rather than repair, and tissue-engineered skin may match the quality of split-skin autografts, our present gold standard.

Animals↗
PubMed2003

Engineering of muscle tissue.

The loss or failure of an organ or tissue is one of the most frequent, devastating, and costly problems in health care. Tissue engineering and regenerative medicine is an emerging interdisciplinary field that applies the principles of biology and engineering to the development of viable substitutes that restore, maintain, or improve the function of human tissues and organs. Tissue engineering science has provided critical new knowledge that will deepen our understanding of the phenotype of an important category of cell types-the muscle cells-and this knowledge may enable meaningful advances in musculoskeletal tissue engineering. There are two principle strategies for the replacement of impaired muscle tissues. One approach uses the application of isolated and differentiated cells (in vivo tissue engineering), using a transport matrix for the cell delivery; the other uses in vitro-designed and pre-fabricated tissue equivalents (in vitro tissue engineering). Future developments and the decision regarding which approach is more promising depend on the elucidation of the relationships among cell growth and differentiation, the three-dimensional environment, the architecture of the cells, and gene expression of the developmental process and the survival of the cells and integration in the host in in vivo experiments. As the techniques of tissue engineering become more sophisticated and as issues such as vascularization and innervation are addressed, the usefulness of these methods for reconstructive surgery may grow significantly.

Humans↗
PubMed2001

Fibrin glue as matrix for cultured autologous urothelial cells in urethral reconstruction.

In the present study, we have established a technique to create an artificial urethra in a rat animal model by transplantation of in vitro-expanded urothelial cells onto an in vivo-prefabricated tube formation using tissue engineering methods. Urothelial cells from isogenic rats were harvested for culture. A silicon catheter was used to induce a connective tissue capsule-tube formation underneath the abdominal skin. Two weeks later, the cultivated urothelial cells were seeded onto the lumen of this tube using fibrin glue as delivery matrix. The histomorphological and immunohistochemical studies revealed a viable multilayered urothelium, lining the inner surface of the prior formed connective tissue tube-formation 4 weeks after grafting the cells. We have shown that cultured and in vitro-expanded urothelial cells can be successfully reimplanted onto a prefabricated tube-like structure using fibrin glue as a delivery matrix and native cell expansion vehicle. The results suggest that the creation of an artificial urethra may be achieved in vivo using tissue engineering methods, showing potential for urethral reconstruction and providing autologous urothelium for reconstructive surgery in the genitourinary tract.

Animals↗
PubMed2000

Hemangiosarcoma of the left hand in a patient with the rare combination of Maffucci's and Stewart Treves syndrome.

We describe a patient with the previously unseen combination of Maffucci's and Stewart Treves syndrome who presented with an angiosarcoma of the hand. Maffucci's syndrome is characterized by the presence of multiple enchondroma and soft tissue hemangioma. The syndrome is a rare nonhereditary condition with a usual onset in childhood. Malignant transformations are a common feature of this syndrome. In 1948, Stewart and Treves first described six cases of lymphangiosarcoma after radical mastectomy. This syndrome is an unusual form of angiosarcoma occuring as a complication of lymphedema. Chronic lymphedema and lymphangiectasia preceding lymphangiosarcoma may not only be induced by radical mastectomy with axillary lymph node dissection and postoperative radiation therapy. Posttraumatic, congenital or spontaneous chronic lymphedema may also be associated with lymphangiosarcoma. A time interval of many years seems to be required before malignant transformation develops. Generally the syndrome has a very poor prognosis. Both syndromes described above are of a rare frequency. We report this case because of prior unknown coincidence of both syndromes.

Amputation, Surgical↗
PubMedDate not supplied

Skeletal muscle tissue engineering.

The reconstruction of skeletal muscle tissue either lost by traumatic injury or tumor ablation or functional damage due to myopathies is hampered by the lack of availability of functional substitution of this native tissue. Until now, only few alternatives exist to provide functional restoration of damaged muscle tissues. Loss of muscle mass and their function can surgically managed in part using a variety of muscle transplantation or transposition techniques. These techniques represent a limited degree of success in attempts to restore the normal functioning, however they are not perfect solutions. A new alternative approach to addressing difficult tissue reconstruction is to engineer new tissues. Although those tissue engineering techniques attempting regeneration of human tissues and organs have recently entered into clinical practice, the engineering of skeletal muscle tissue ist still a scientific challenge. This article reviews some of the recent findings resulting from tissue engineering science related to the attempt of creation and regeneration of functional skeletal muscle tissue.

Animals↗
PubMedDate not supplied

Impact of electrical stimulation on three-dimensional myoblast cultures - a real-time RT-PCR study.

Several focal skeletal muscle diseases, including tumours and trauma lead to a limited loss of functional muscle tissue. There is still no suitable clinical approach for treating such defects. A promising approach could be the tissue engineering of skeletal muscle. However, a clinically reliable differentiation stimulus for three-dimensional (3-D) cultures is necessary for this process, and this condition has not yet been established. In order to quantify and analyze the differentiation potential of electrical cell stimulation, primary myoblasts were stimulated within a 3-D fibrin- matrix. Gene expression of MyoD, myogenin and AChR-epsilon were measured by real-time RT-PCR over a time period of eight days, showing immediate down-regulation of all marker genes. For tissue engineering approaches, cell multiplication is crucial for acquisition of sufficient tissue volumes for reconstruction. Therefore, all experiments were performed with high and low passaged myoblasts, demonstrating higher transcript rates of marker genes in lowpassage cells. Our findings strongly suggest a reconsideration of electrical stimulation in muscle tissue engineering.

Animals↗
PubMedDate not supplied

A new approach to tissue engineering of vascularized skeletal muscle.

Tissue Engineering of skeletal muscle tissue still remains a major challenge. Every neo-tissue construct of clinically relevant dimensions is highly dependent on an intrinsic vascularisation overcoming the limitations of diffusion conditioned survival. Approaches incorporating the arteriovenous-loop model might bring further advances to the generation of vascularised skeletal muscle tissue. In this study 12 syngeneic rats received transplantaion of carboxy-fluorescine diacetate-succinimidyl ester (CFDA)-labelled, expanded primary myoblasts into a previously vascularised fibrin matrix, containing a microsurgically created AV loop. As control cells were injected into fibrin-matrices without AV-loops. Intra-arterial ink injection followed by explantation was performed 2, 4 and 8 weeks after cell implantation. Specimens were evaluated for CFDA, MyoD and DAPI staining, as well as for mRNA expression of muscle specific genes. Results showed enhanced fibrin resorption in dependence of AV loop presence. Transplanted myoblasts could be detected in the AV loop group even after 8 weeks by CFDA-fluorescence, still showing positive MyoD staining. RT-PCR revealed gene expression of MEF-2 and desmin after 4 weeks on the AVloop side, whereas expression analysis of myogenin and MHC(embryo) was negative. So far myoblast injection in the microsurgical rat AV loop model enhances survival of the cells, keeping their myogenic phenotype, within pre-vascularised fibrin matrices. Probably due to the lack of potent myogenic stimuli and additionally the rapid resorption of the fibrin matrix, no formation of skeletal muscle-like tissue could be observed. Thus further studies focussing on long term stability of the matrix and the incorporation of neural stimuli will be necessary for generation of vascularised skeletal muscle tissue.

Animals↗