Skin Elastic Stretch For Repair Skin Defects On Limbs

The skin defect of limbs, which might result in the exposure of bones, tendons,nerves and vessels, was usually caused by trauma, infection, vascular diseases and iatrogenic factors(such as skin flap). Mild patients may be suffered the limb dysfunction, delaying of wound healing, long term hospitalization, disability of work and decline of live quality. Some severe patients may be suffered the necrosis of exposed bone, never and tendon; the infection of bone, vessel embolism even amputation. There are many treatment methods to deal with the skin defect wound,such as external application of herbal medicine, skin grafting, skin flap, subcutaneous expansion and skin stretching. However, up to now any treatment methods have indications and disadvantages. That is, there is no optimum method for dealing with all skin defect wound. Small skin defect can be managed with herbal medicine while larger wounds and wounds with exposure of bone are not suitable. Skin grafting is an optimum for wound with good granulation tissue, but not suitable for wound with exposure of bone and tendons or in joint position. Skin flap grafting and transfer can solve the problem of bone exposure, only if the surgeons have the appropriate technology. Besides, subcutaneous expansion is not suitable for fresh wound. Skinstretching needs some special devices and may result in some implications such as pain, necrosis of edge of skin and falling off dilator. However, the skin appearance,texture, hair growth, tactile sensation of wounds dealt with skin stretching was completely similar with normal skin. Therefore, it is extremely necessary for developing a new skin stretching method.Part ?: The feasibility study of elastic skin stretching for repair of skin defectObjective: To study the feasibility of elastic skin stretching method with osseous pins and medical silicone tubes.Methods: Six white pigs were experimental animal model. Two skin defects,which located on the symmetrical position of back, were made in each pig. All wounds were designed as rectangle with 12cm×8cm. Eight of wounds(numbered 1-8)were experimental group and four wounds(numbered 9-12) were control group. The wounds in experimental group were dealt with elastic skin stretching method designed by ourselves, while the wounds in control group only covered with iodophor gauze and bandaged with sterile gauze. Pigs in experimental group were put in special cages to restrict activity and dressing the wound every day. The force of silicone tubes were adjusted depending on the skin color, capillary reaction, wound healing and tension of tube. Wounds in control groups were dressed routinely.Results: The wounds healing in experimental groups were significantly faster than control groups especially in the first 3 days and they would closed in 6th day.The wounds healing in control groups were slower. The daily reduced areas of wounds were significantly different with statistical analysis(P<0.05).Conclusion: The self designed elastic skin stretching method with osseous pins and medical silicone tubes will promote skin expansion and accelerate closure of wound.Part II: Clinical Application of Skin Elastic Stretch for Repair Skin Defects on LimbObjective: To investigate the practice of skin stretch by round osseous pins and medical silicone tubes for treating skin defects on limbs.Methods: A total of 70 patients(male 49, female 21) had received therapy of skin stretching by osseous pins and medical silicone tubes for skin defects on limbs between December 2006 and February 2015, they aged between16 and 56, 35 in average. Positions of defects were on feet and ankles(n = 12), shins(n = 38), thighs(n = 8), hands(n = 8) or shoulders(n = 4). Causes of skin defects were post traumatic skin necrosis(n = 28), incision of compartment syndrome(n = 8), skin flap necrosis(n = 8), skin flap graft(n = 10), diabetic foot(n = 8). Complications were bone fractures(n = 27), injured nerves or vessels(n = 15), wound infection(n = 18). Areas of skin defects were between 10 cm×16 cm- 2 cm×3 cm. First, the defect area was cleaned, two round osseous pins were driven though both edges of the defect area, for irregular edges, multiple short osseous pins were applied to fix the edges. Aseptic silicone tubes were used to link the two osseous pins on the edges horizontally, then the silicone tubes were pulled and tightened to tension the skin, pulling the wound edges together, at the same time blood supply can be shown by capillary vessels in the skin edges, tension of the tubes was kept and tubes were tided while it had been made sure that no more necrosis would be caused on the skin edges. Aseptic surgical dressings were used to cover the defects and changed when there was effusion.Vasodilators and microcirculation improving agents were used afterward. Use of antibiotics depended on area of defects and condition of infections, and selection of antibiotics were based on culture of bacteria on the defects and antibacterial susceptibility test. Tension of the tubes should be monitored and adjusted according to blood supply, dressings were changed when there was effusion. When the defects were closed, the skin edges were sewn up.Results: A total of 61 subjects were completely healed, their defects were completely closed after skin stretch, for 36 patients, defects were closed after the first operation and the skin edges were sewn after the defects were closed. Other 10 patients had underwent several stretches because large defect area, long stretch duration or infection had caused the osseous pins to cut through the skin edges and detach, and their defects were finally closed by sewing up skin edges or dress changing, no skin grafting or flap restoration were performed. Seven were partially responded. They had experienced partial close of defects but finally were given skin grafting. Two were not responded, no reduction of defect area was observed, flap grafting was required. The total response rate was 97.1%, follow-up periods were8-14 months. Comparing to normal skin, the stretched skins showed normal color,elasticity, hair growth, touch and pain, without being swollen.Conclusion: Skin stretch by osseous pins and medical silicone tubes can stretch the skins to completely or partially close skin defects, it is an effective therapeutic method for skin defects on limbs.Part ?: The mechanic research of elastic skin stretching for repair of skin defectObjective: To study the force on per unit length of skin and each silicone tubes during elastic skin stretching, and determine the reference value of safety force in elastic skin stretching.Methods: A total of 10 patients(male 8, female 2) had received therapy of skin stretching between December 2006 and February 2015, they aged between18 and 55,34 in average. All wounds were located on lower legs and areas of skin defects were between 3 cm×2 cm-12 cm×8 cm. 7 patients had fracture of fibula without injury of major vessels of legs, and 5 of them were treated with external fixation while the other 2 patients were treated with plate internal fixation. Elastic skin stretching was performed in the first week postoperatively. One round osseous pin was driven in dermis layer and though one skin edge of defect area with 1.5cm distance from edge.After another one pin was driven in opposite edge, the aseptic silicone tubes were used to link the two osseous pins. One tube was used when the length of skin edge was 3cm to 6cm and two tubes for 6cm to 9cm and three tubes for 9cm to 12 cm. The skin temperature measurement points were marked in the central of skin edge and2 cm from edge. The skin temperatures were measured with electronic skin temperature meter before stretching. A large force was performed and then a temporary knot was made when capillary reaction time of skin around pins was significantly longer than the peripheral skin or capillaries didn't fill. The forces of silicone tubes were reduced gradually and we measured the capillary reaction time and skin temperature. The sterile pulling force instrument was fastened to the central point of one pin and the other pin was fixed. We defined the force of skin from silicone tubes as the value when we pulled the pulling force instrument till all tubes were completely slack. We could obtain the force per silicone tube when this value was divided by number of tubes and the force per unit length skin when this value was divided by the length of skin edge(cm).Results: The average force on per unit length skin(cm) was 1.11±0.22 Kg in10 patients. The average force on each silicone tube was 4.18±0.38 Kg.Conclusion: The optimal force on per unit length skin edge was 1.11±0.22 Kg and on each silicone tube was 4.18±0.38 Kg when elastic skin stretching method was utilized.