William C. Lineaweaver

The effect of vascular endothelial growth factor on the healing of ischaemic skin wounds

The effect of exogenous vascular endothelium growth factor (VEGF) on wound healing in an ischaemic skin flap model was evaluated in this study. Seventy-two Sprague-Dawley rats were used. Normal incisional wound and H-shaped double flaps were used as the wound models. The study was divided into two parts. In Part I, VEGF protein levels were determined from the incisional and H-shaped ischaemic wounds at 12 and 24 h, postoperatively. In Part II, tensile strength and immunohistochemical stains were examined to determine the level of microvessel density (MVD) at 1 and 2 weeks, postoperatively in simple incisional wounds, ischaemic wounds, and ischaemic wounds following 1 ml (1 microg/ml) exogenous VEGF injections into the subcutaneous tissue. The results showed a significantly higher level of VEGF protein in the ischaemic wounds than the incisional wounds. Tensile strength was statistically higher in the incisional wound group and in the ischaemic flap wounds with VEGF treatment compared to the ischaemic flaps with no treatment at 1 week, postoperatively (p>0.05). MVD data indicated that ischaemic wound repair with VEGF treatment had significantly higher MVD than the normal incisional wounds and ischaemic wounds without treatment. We conclude that exogenous application of VEGF can increase early angiogenesis and tensile strength in the ischaemic wound.

Vascular endothelial growth factor (VEGF) expression and the effect of exogenous VEGF on survival of a random flap in the rat

The induction of endogenous vascular endothelial growth factor (VEGF) production in the skin flap with ischemic injury and the effect of exogenous VEGF on survival of the ischemic skin flap were studied in rats. A dorsal flap model (3x10 cm(2)) was used in this study. In Part I, biopsies were taken from the flap at 2.5, 5.5, and 8.5 cm distances from the distal edge at 0, 6, 12, and 24 h after the flaps were sutured. Malonyldialdehyde (MDA) and VEGF(165) protein level were measured. In Part II, exogenous VEGF (1 microg/ml) was injected subdermally into the flaps in 14 rats before the flaps were replaced. Flaps that received a saline injection were used as the controls. The skin paddle survival was measured on postoperative day five. The results showed that the MDA level in the distal part of the flap significantly increased at 24 h postoperatively when compared to MDA in other parts of the flap. However, VEGF levels in the distal part of the flap significantly decreased when compared to the middle part of the flap. Subdermal injection of exogenous VEGF to the distal area of the flap could significantly improve survival of the distal flap (89% of total skin paddle) when compared to the control, which had a 64% mean percent survival. We conclude that production of endogenous VEGF protein is significantly increased in the skin flap with mild ischemia, but decreased in the flap with severe ischemia. Administration of exogenous VEGF could significantly enhance survival of ischemic flaps.

Fracture fixation in the mutilated hand

Early anatomic (or near anatomic; lingers do not impinge or overlap during flexion or extension) stable fracture fixation provides the foundation for successful wound management and for the repair, reconstruction, and healing of all damaged tissues in a mutilating hand injury. It also plays an instrumental role in pain control and affords an optimal opportunity for timely and favorable rehabilitation of and recovery from mutilating injuries of the hand. Kirschner or other wiring systems or mini external fixators may be used for simple fractures, in children, when rapid fracture fixation is necessary, and for provisional fracture fixation. Mini plates should be considered for fractures with comminution or loss and in instances of multiple fractures. Fingers with segmental injury of three or more tissues should be considered for early amputation to avoid prolonged and impaired recovery of the hand. Every effort should be made to preserve the thumb and its function by repair or reconstruction.

Nerve conduits for nerve reconstruction

Abstract Although autogenous nerve grafting remains the gold standard for repair of peripheral nerve defects, the use of various conduits can be a substitute provided these conduits meet the above-mentioned prerequisites. For the moment, autogenous vein grafts or denatured muscle grafts can be used to bridge short defects, especially in distal sensory nerves. Incorporation of muscle into a vein graft expands its application to longer defects in bigger nerves. PGA conduits have also been clinically proven to be reliable in reconstruction of digital nerve defects. Although nonabsorbable conduits cause irritation and nerve compression that necessitates secondary surgery removal, silicone tubes or Goretex tubes can be used in selected cases until absorbable conduits large enough for major peripheral nerves are available. To date, 3 cm seems to be the barrier for conduits. Incorporation of trophic factors and Schwann cells into the conduits will make their way into the clinic if problems like controlled release of trophic factors, obtaining and sustenance of an appropriate number of viable Schwann cells, are solved.

Complete salvage of impending free flap failure in heparin induced thrombocytopenia by emergent institution of therapy with argatroban

effective. As long as it does not permit shearing of the skin graft on the skull, the end result will be good. Where flap reconstruction with vascularised tissue is contraindicated, this technique provides a reliable, quick and simple way of providing skin cover (Figures 13e16). However, the decision as to whether this functions as a definitive form of cover or as a temporary measure must be individualised to the patient.

Effect of taurine on rat Achilles tendon healing

Abstract Taurine has anti-inflammatory and antioxidant characteristics. We have introduced taurine into a tendon-healing model to evaluate its effects on tendon healing and adhesion formation. Two groups of 16 rats underwent diversion and repair of the Achilles tendon. One group received a taurine injection (200u2009mg/ml) at the repair site, while the other group received 1u2009ml of saline. Specimens were harvested at 6 weeks and underwent biomechanical and histological evaluation. No tendon ruptured. Average maximum load was significantly greater in the taurine-applied group compared with the control group (pu2009<u20090.05). Similarly, average energy uptake was significantly higher in the taurine-applied group compared with the control group (pu2009<u20090.05). We observed no significant differences in stiffness in both groups (pu2009>u20090.05). After histological assessment, we found that fibroblast proliferation, edema, and inflammation statistically decreased in the treatment group (pu2009<u20090.05). These findings could indicate greater tendon strength with less adhesion formation, and taurine may have an effect on adhesion formation.

New microsurgical applications: implications for the infrastructures of plastic surgery.

As a technical innovation, microsurgery has changed concepts and strategies throughout plastic surgery. The infrastructures of plastic surgery currently are evolving in ways that make the identity and future of the specialty uncertain. Microsurgery also may be a basis for fresh thoughts in these areas of infrastructure. This article touched on some areas where microsurgery could be an important element in organizational development, namely patient population identification, economic strategies, academic organization, and medical education. More thorough exploration of these ideas and identification of others may result in a new foundation for plastic surgery with microsurgery as a key element.

Combining regenerative medicine strategies to provide durable reconstructive options: auricular cartilage tissue engineering

Recent advances in regenerative medicine place us in a unique position to improve the quality of engineered tissue. We use auricular cartilage as an exemplar to illustrate how the use of tissue-specific adult stem cells, assembly through additive manufacturing and improved understanding of postnatal tissue maturation will allow us to more accurately replicate native tissue anisotropy. This review highlights the limitations of autologous auricular reconstruction, including donor site morbidity, technical considerations and long-term complications. Current tissue-engineered auricular constructs implanted into immune-competent animal models have been observed to undergo inflammation, fibrosis, foreign body reaction, calcification and degradation. Combining biomimetic regenerative medicine strategies will allow us to improve tissue-engineered auricular cartilage with respect to biochemical composition and functionality, as well as microstructural organization and overall shape. Creating functional and durable tissue has the potential to shift the paradigm in reconstructive surgery by obviating the need for donor sites.

Bovine fetal collagen reinforcement in a small animal model of hernia with component repair

BACKGROUNDnComponent separation is a surgical strategy used to achieve abdominal wall reconstruction for patients with significant ventral hernias. With an increasing number of variations in procedural techniques and materials, the development of a small animal model of this surgery would allow for the controlled evaluation of variables with analytics not available in human clinical studies. To test this model, we investigated the reinforcement of these component repairs in rats with a bovine fetal collagen (BFC) scaffold.nnnMETHODSnFifty Sprague Dawley rats were randomized into either component repair alone or BFC reinforced component repair. At time points up to 1 y, these groups were evaluated for hernia formation, strength of repair, strength of mesh-muscle interface, and histology of the repair site.nnnRESULTSnAnterior component separation was achievable and reproducible in this small animal model. Significantly fewer hernias were found in BFC reinforced repairs. The change in transverse abdominal length was lower for reinforced repairs indicating less external oblique retraction, and reinforced repairs were consistently stronger than controls through 1 y. BFC was revascularized and repopulated with host cells but not rapidly degraded.nnnCONCLUSIONSnThis small animal model of hernia repair with anterior component separation was effective in evaluating the reinforcement of a hernia repair with mesh. It may be useful in future work for the controlled, comparative investigation of different repair techniques and mesh materials in anterior component separation hernia repairs. Additionally, bovine fetal collagen was found to effectively reinforce component repairs and undergo an assimilation process including rapid revascularization and repopulation with host cells followed by gradual extracellular matrix remodeling.