Dae-Hyun Lew

Simultaneous reconstruction of the Achilles tendon and soft-tissue defect using only a latissimus dorsi muscle free flap.

The combined loss of the Achilles tendon and the overlying soft tissue in the young ambulant patient with expectations of a normal life is a challenging problem. These patients need not only soft tissue but also dynamic and functional reconstruction. Four cases of major defects of the Achilles tendon and overlying soft tissue after trauma are presented. In each case, the tendon and the overlying soft tissues were reconstructed using only a latissimus dorsi muscle free flap and overlying split-thickness skin graft. In conventional methods, evolved in the reconstruction of the Achilles tendon and soft tissue, the size of the defect was a limit. However, this technique can be used to reconstruct an extensive defect, including distal calf muscle to the plantar metatarsal area. In one case, the flap was harvested in a myocutaneous unit, and the skin portion was deepithelialized for the coverage and enough padding on the bony exposure area in reverse position. The purpose of the present study was to reevaluate the potential of denervated muscle flap for a force-bearing conduit as an alternative reconstructive method of the Achilles tendon. The denervated latissimus dorsi muscle in this study eventually experienced the process of atrophy and fibrosis but maintained its original length. Although there remained some atrophic muscle fibers, a fibrosis of the muscle fibers formed a tendon-like fibrous band, and so the action of the posterior calf muscle could be transmitted through the tendon-like fibrotic change of the denervated latissimus dorsi muscle. The advantages of this technique are that (1) it is a single procedure, (2) it is adaptable to a wide range of defect sizes, (3) it allows faster wound healing supported by well-vascularized tissues, (4) it produces satisfactory function of the ankle joint and a padding effect, and (5) it produces good contour of the posterior calf to the sole and an acceptable donor-site morbidity.A two-part investigation was undertaken to determine whether a four- or a five-flap Z-plasty gives the greatest increase in length (deepening) over the same radius of a web. In part A, flaps were designed on a model of a webspace made from a plastic frame and Speedo fabric; four types of flaps, three different central limb lengths, and three trials for each length gave a total of 36 observations. In part B, flaps were designed on the natural axillary webs of the pig; three Yorkshire pigs with one type of flap per axillary web gave a total of 12 observations. In part A, the stereometric elongation (percent deepening) produced by the five-flap Z-plasty was similar to that of a single 60-degree Z-plasty (4-cm central limb; five-flap versus a single Z procedure, 72.5 ± 4.3 versus 75.0 ± 2.5 percent). The 90-degree four-flap procedure gave a 1.59 times greater deepening than the five-flap procedure (4-cm central limb; 90-degree four flap technique, 114.2 ± 1.4 percent). The 120-degree four-flap technique gave 2.0 and 1.26 times greater deepening than the five-flap and 90-degree four-flap procedures, respectively (4-cm central limb; 120-degree four-flap technique, 144.2 ± 1.4 percent). In part B, the 90-degree four-flap Z-plasty again produced a significantly greater lengthening (1.57 times) than the five-flap procedure (132.7 ± 6.4 versus 84.0 ± 4.0 percent; p < 0.05), and the percentage of elongation of the 120-degree four-flap procedure was 1.27 times greater than that of the 90-degree four-flap technique (167.3 ± 7.0 versus 131.3 ± 2.3 percent; p < 0.05). In conclusion, the four-flap Z-plasty produced greater webspace deepening than that of the five-flap Z-plasty. The 120-degree four-flap procedure gave the greatest percentage of elongation, but it was more difficult to design and close than the 90-degree four-flap Z-plasty.

Effects of human cord blood mesenchymal stem cells on cutaneous wound healing in leprdb mice.

Purpose:In the present study, we used the diabetic mouse as a model of delayed wound healing to investigate the effects of human cord blood mesenchymal stem cells (CB-MSC) on wound healing. Methods:A delayed wound healing model was used by db/db mice. Study models were divided by an injection of human CB-MSC with phosphate buffered solution (PBS) by a different method. One was a locally topical injection, the other was a systemic injection via the end tail vein. Both models were treated with 2.0 × 106 CB-MSC after an 8-mm full thickness defect was made by a skin punch biopsy on the back. We evaluated the wound size, transforming growth factor (TGF)-&bgr;, and vascular endothelial growth factor histologic evaluation, and vessel counts. Engraft of CB-MSC was detected by an antihuman antibody. Result:Wound healing was accelerated in the experimental group in the topical injection model with statistical significance on the 6th, 9th, and 12th day (P < 0.05). In the systemic injection model, wound healing was completed from the 9th day, but there was no statistical significance. TGF-&bgr; increased in the first week and decreased in the third week in the experimental groups of both models. But there were opposite results in the control groups of both models. The statistical differences were found in first and third week in topical injection and in the third week in systemic injection (P < 0.05). Vascular endothelial growth factor increased in all groups and in all models as the wound healing. But statistical significance did not show between all experimental and control groups. Anti-human antibody immunochemical staining was positive in the wound. Conclusion:We concluded that CB-MSC had a positive effect on wound healing. Statistically significant results were noted in the topical injection model. We also reported good effects on the systemic injection model, although we did not find any statistical significance. CB-MSC may influence wound healing by TGF-&bgr;.

De novo induction of island capsule flap by using two silastic sheets: Part 1. Generation.

A new experimental model for de novo generation of an axial pattern island flap has been designed in a rat model. The purpose of this study was to make a sufficient vascular carrier, as an island capsule flap, with only vascular pedicles and addition of collagen fibers induced by foreign-body reaction. The femoral arteriovenous bundle was isolated and sandwiched between two 2.5 x 1.5 cm Silastic sheets. Eight weeks later, as a delay procedure, femoral vessels were ligated at the distal end of the Silastic sheets and the four margins of the sheets were divided except for the vascular pedicle. This capsule flap was raised as a secondary island flap connected only by its vascular pedicle, then it was sutured back in place. Ten days after the delay procedure, the upper Silastic sheet was removed and a full-thickness skin graft was performed on the capsular island flap. Animals were killed at 80 days. A total of 40 axial pattern capsulocutaneous flaps from 20 Sprague-Dawley rats were successfully achieved. Pathologic study revealed neovascularization, and abundantly impregnated vascular structures near the pedicle were observed with randomly developed collagen fibers. The skin graft took 100 percent on this newly formed capsular flap; therefore, the capsule structure was able to survive on its own and support skin grafts. This experiment, by using an isolated femoral artery and vein as the main pedicle, led to the formation of a capsule flap through a normal foreign body reaction between two Silastic sheet implants. This new flap can be used as a reliable vascular carrier for various needs with minimal donor morbidity.

Effect of Endogenous Bone Marrow Derived Stem Cells Induced by AMD-3100 on Expanded Ischemic Flap

The purpose of this study was to devise an expanded ischemic flap model and to investigate the role of AMD-3100 (Plerixafor, chemokine receptor 4 inhibitor) in this model by confirming its effect on mobilization of stem cells from the bone marrow. Male Sprague-Dawley rats were used as an animal research model. The mobilization of stem cells from the bone marrow was confirmed in the AMD-3100-treated group. The fractions of endothelial progenitor cells (EPC) and the vascular endothelial growth factor receptor (VEGFR) 2+ cells in the peripheral blood were increased in groups treated with AMD-3100. The expression of vascular endothelial growth factor (VEGF) was increased in response to expansion or AMD injection. The expression of stromal cell derived factor (SDF)-1 and VEGFR2 were increased only in unexpanded flap treated with AMD-3100. Treatment with AMD-3100 increased both the number and area of blood vessels. However, there were no statistically significant differences in the survival area or physiologic microcirculation in rats from the other groups. This endogenous neovascularization induced by AMD-3100 may be a result of the increase in both the area and number of vessels, as well as paracrine augmentation of the expression of VEGF and EPCs. However, the presence of a tissue expander under the flap could block the neovascularization between the flap and the recipient regardless of AMD-3100 treatment and expansion. Graphical Abstract