M. Voigt

Tissue engineering in plastic reconstructive surgery

Tissue engineering (TE) is a new interdisciplinary field of applied research combining engineering and biosciences together with clinical application, mainly in surgical specialities, to develop living substitutes for tissues and organs. Tissue engineering approaches can be categorized into substitutive approaches, where the aim is the ex vivo construction of a living tissue or organ similar to a transplant, vs. histioconductive or histioinductive concepts in vivo. The main successful approaches in developing tissue substitutes to date have been progresses in the understanding of cell–cell interactions, the selection of appropriate matrices (cell–matrix interaction) and chemical signalling (cytokines, growth factors) for stimulation of cell proliferation and migration within a tissue‐engineered construct. So far virtually all mammalian cells can be cultured under specific culture conditions and in tissue specific matrices. Future progress in cell biology may permit the use of pluripotent stem cells for TE. The blueprint for tissue differentiation is the genome: for this it is reasonable to combine tissue engineering with gene therapy. The key to the progress of tissue engineering is an understanding between basic scientists, biochemical engineers, clinicians, and industry. Anat Rec 263:372–378, 2001.

Effect of Ultrasonic Assisted Lipectomy (UAL) on Breast Tissue: Histological Findings

Abstract. As the use of ultrasound-assisted liposuction (UAL) increases, the technique grows more popular in breast surgery, especially in reduction mammaplasty and treatment of gynecomastia. The aim of our study was to investigate the effect of UAL on breast tissue using histological examinations, and analyze the effect of this technique on a cellular level.Biopsies from 10 patients undergoing ultrasonically assisted lipectomy prior to classic reduction mammaplasty were taken from the treated areas of the breast. Biopsies were fixed in formalin and embedded in paraffin. Sections were stained with hematoxilin-eosin, and analyzed for defective adipocytes, and the effects of UAL on breast tissue. Untreated breast tissue and breast tissue that had been treated only with conventional aspiration lipectomy served as controls. Sections were analyzed using light microscopy. Compared to the breast tissue treated only with conventional lipectomy, a stronger destruction of the cellular structure of adipocytes could be detected. The destruction was visible even in areas more distant from the aspiration channel. In contrast, the breast tissue was mostly intact, no signs of ultrasonic-induced cellular destruction were visible. The glandular structure was kept intact. Beside the direct mechanical destruction by the probe and the canula, no further alterations of the cellular integrity of the glandular parts were visible.In conclusion our results indicates that UAL is also a safe technique for use in breast surgery. Besides easy handling and improved modelling, the destructive effect of the ultrasound does not include the glandular breast tissue.

Management of hypovascularized wounds not responding to conventional therapy by means of free muscle transplantation.

Background: Chronic ulceration as a complication of arteriosclerotic disease, venous congestion or diabetes mellitus is still a serious clinical problem, resulting in immobilization, extended hospitalization and cost-intensive treatment. Other than standard conservative treatment protocols or early amputation, microsurgical free transfer of well vascularized muscle tissue onto chronic wounds can induce angiogenesis and improve wound healing even in the hypovascularized wound. Patients: From 1993–1999 we treated 12 patients (mean age: 46 years) with vascular ulcers of the lower extremity with free muscle or fasciocutaneous tissue transfer. Results: The average hospitalization was 51.4 days. The perioperative mortality was zero. In one patient with factor V deficiency a partial flap necrosis occurred. Two revisions of the micro anastomoses had to be performed. Two seromas occurred at the donor site. No secondary flap loss was observed. Extremity or stump length preservation was achieved in all cases. Conclu...BACKGROUND Chronic ulceration as a complication of arteriosclerotic disease, venous congestion or diabetes mellitus is still a serious clinical problem, resulting in immobilization, extended hospitalization and cost-intensive treatment. Other than standard conservative treatment protocols or early amputation, microsurgical free transfer of well vascularized muscle tissue onto chronic wounds can induce angiogenesis and improve wound healing even in the hypovascularized wound. PATIENTS From 1993-1999 we treated 12 patients (mean age: 46 years) with vascular ulcers of the lower extremity with free muscle or fasciocutaneous tissue transfer. RESULTS The average hospitalization was 51.4 days. The perioperative mortality was zero. In one patient with factor V deficiency a partial flap necrosis occurred. Two revisions of the micro anastomoses had to be performed. Two seromas occurred at the donor site. No secondary flap loss was observed. Extremity or stump length preservation was achieved in all cases. CONCLUSIONS Optimal postoperative treatment with physiotherapy and orthopaedic shoe support is important. If all these factors are present and if the patient is highly motivated a reintegration into normal life can be achieved.

Experiences with rigid internal fixation using a low volume titanium implant system in metacarpal and phalangeal fractures

Abstract Our experience using the low volume titanium mini-fragment system ”Profile Titan” is presented retrospectively. The system contains self-tapping miniscrews with countersinking heads and very small adaptable plates with rounded edges. The study consists of 53 patients who underwent osteosynthesis, arthrodesis, or corrective osteotomy of the hand skeleton from 1 January 1994 to 31 March 1995. Functional results were evaluated and standard postoperative X-rays were taken at 1, 2, and 4 weeks after injury. Fifty-three patients with 56 fractures were treated. Results show that 78% of patients regained complete recovery of active range of motion. Fractures with and without negative prognostic factors were compared. There were three major postoperative complications not related to the type of implant. Compared to the AO mini system this system has several advantages.

Three-dimensional reconstruction of a defect of the frontozygomatic area by custom made Proplast II implant

Abstract Alloplastic materials are a valid alternative to autologous bone grafts in contour defects of the facial skeleton. Biomaterials also reduce donor site morbidity. In addition, alloplastic materials can be contoured exactly as needed. Computed tomography (CT) scan digital data can be computed into three-dimensional data for 1:1 stereolithographic reconstruction of the complete skull or segments as required. The design of an implant for defect reconstruction may even be computed as a mirror image of the unaffected undeformed side. Therefore it is common to perform phantom operations on stereolithographically built models from the patient’s head before a complex reconstruction is done. Proplast II has an advantage over other materials, such as hydroxyapatite, titanum, gold, silicone, and polymethylmetacrylate (PMMA), because of the low weight, the fact that the material can be carved with a sharp scalpel, and the possible integration into fibrous and bone tissue. Proplast II is semirigid and can easily be sutured to the bony defect.

Management therapierefraktärer hypovaskularisierter Wunden durch freie Muskelverpflanzung

Background: Chronic ulceration as a complication of arteriosclerotic disease, venous congestion or diabetes mellitus is still a serious clinical problem, resulting in immobilization, extended hospitalization and cost-intensive treatment. Other than standard conservative treatment protocols or early amputation, microsurgical free transfer of well vascularized muscle tissue onto chronic wounds can induce angiogenesis and improve wound healing even in the hypovascularized wound. Patients: From 1993–1999 we treated 12 patients (mean age: 46 years) with vascular ulcers of the lower extremity with free muscle or fasciocutaneous tissue transfer. Results: The average hospitalization was 51.4 days. The perioperative mortality was zero. In one patient with factor V deficiency a partial flap necrosis occurred. Two revisions of the micro anastomoses had to be performed. Two seromas occurred at the donor site. No secondary flap loss was observed. Extremity or stump length preservation was achieved in all cases. Conclu...BACKGROUND Chronic ulceration as a complication of arteriosclerotic disease, venous congestion or diabetes mellitus is still a serious clinical problem, resulting in immobilization, extended hospitalization and cost-intensive treatment. Other than standard conservative treatment protocols or early amputation, microsurgical free transfer of well vascularized muscle tissue onto chronic wounds can induce angiogenesis and improve wound healing even in the hypovascularized wound. PATIENTS From 1993-1999 we treated 12 patients (mean age: 46 years) with vascular ulcers of the lower extremity with free muscle or fasciocutaneous tissue transfer. RESULTS The average hospitalization was 51.4 days. The perioperative mortality was zero. In one patient with factor V deficiency a partial flap necrosis occurred. Two revisions of the micro anastomoses had to be performed. Two seromas occurred at the donor site. No secondary flap loss was observed. Extremity or stump length preservation was achieved in all cases. CONCLUSIONS Optimal postoperative treatment with physiotherapy and orthopaedic shoe support is important. If all these factors are present and if the patient is highly motivated a reintegration into normal life can be achieved.

Chirurgisch induzierte Angiogenese als Grundlage der Behandlung hypovaskularisierter Wunden — der nutritive Lappen

Chronische Wunden der unteren Extremitaten als Folge von Diabetes, Arteriosklerose und Mikroangiopathie stellen ein bedeutendes klinisches Problem dar, welches in Immobilisierung, langer Hospitalisation und einer kostenintensiven Behandlung resultiert. Mittels Transfer von gut vaskularisiertem Gewebe auf chronische Wunden in Form eines frei transplantierten Muskellappens, gegebenenfalls unter Anschlus an einen Venenbypass, kann Angiogenese induziert und Wundheilung dadurch verbessert werden. Dieses Konzept fuhrt zu einer extremitatenerhaltenden Therapie.

Keratinocytes seeded fibrin micro-carriers reconstitute an epidermis in full thickness wounds

Following the advantages of single cell transplantation in comparison to sheet grafts we improved a spinning culture system for keratinocytes on completely biodegradable micro-carriers. Since previous in vivo investigations with different carrier materials (Cytodex® and PLGA) [Voigt et al. Tissue Eng 8(2):263–272, 2002; Voigt et al. Tissue Eng 5:563–572, 1999] revealed severe cellular inflammatory reactions and persistent remnants of micro-carriers in wounds, the aim of this study was to find a completely biodegradable, physiological and non-toxic material for new micro-carriers. We succeeded in setting up a keratinocyte spinning culture system using fibrin carriers. We were able to reconstitute the epidermis in full thickness wounds in an athymic nude mouse model and in an immunocompetent porcine wound model.

Der mikrochirurgische TRAM (Transverse Rectus Abdominis Myocutan)-Lappen als Standard für die autologe Mammarekonstruktion

Purpose: In reconstructing the female breast after mastectomy the free TRAM flap is superior to other autologous procedures for breast reconstruction. The free TRAM flap provides optimal blood flow to an enormous tissue bulk in the lower abdomen and is the preferable method in autologous breast reconstruction although the technique is very demanding. There is a shift in the last 10 years: an increasing number ofpatients requested breasts reconstruction after a mastectomy, primarily and with autogenous tissue. Material and Methods: Between 1/1995 and 6/2000 in 40 patients 44 breasts were reconstructed with a free TRAM flap after mastectomy (25% immediate reconstructions). During the flap harvest a small perforator bearing muscle segment was incised and the segmental innervation and blood supply preserved leaving the remaining muscle functional. Results: 10 patients had 16 postoperative complications. In 3 cases the anastomosis was revised, 3 patients had a hematoma. There was 1 total flap failure and 2 partly flap necrosis in which the breast mound could be preserved after necrectomy and flap advancement. Hernia or abdominal bulges happened in 3 patients. The average follow-up time was 27.6 months. Conclusion: The results of this study show a low rate of severe complications with the free TRAM flap. The achieved breast volume, the possible breast shape and the natural feel and behaviour of the reconstructed breast makes the TRAM flap the superior method in breast reconstruction.

Comment on “The effect of capsaicin ointment on skin for the survival of a cutaneous flap” by T. Miyawaki et al.

hancement of survival in failing skin flaps by a capsaicin-containing ointment. The study is straightforward and well done. A rat model was chosen in which 2×10 cm abdominal skin flaps were raised which developed necrosis at the distal randomized perfused edge. In this model the effect of capsaicin ointment on skin flap survival was evaluated in four groups, applying the ointment base without capsaicin (group A), capsaicin onto the flap (group B), capsaicin onto the skin around the flap (group C), and capsaicin ointment around the flap and on the flaps skin (group D). Interestingly, best flap survival was achieved in group C, in which capsaicin ointment was applied on the normal abdominal skin sparing the flap itself. One would have expected the best survival to be seen in flaps which were surrounded and topically treated by the ointment (group D). The authors explain this contradiction by suggesting that capsaicin ointment interfered with the wound healing process in the groups in which the ointment was applied topically. However, no wound infection or delayed wound healing was mentioned. A blood steal phenomenon and/or stasis of the flap’s microcirculation due to vasodilation might account for the decreased survival in group D. In addition, the long term depletion of neuropeptides could play a role in controlling the A-V shunts in and around the flap. Some studies suggest these mechanisms [1,2]. Before capsaicin ointment can be used to enhance skin flap survival, one should know where the substance should be placed to achieve the best effect. It might be interesting to design a study comparing capsaicin and nitroglycerin effects on flap survival, because the mechanism of action of nitroglycerin is less complex than that of capsaicin.