A Prospective Randomised Controlled study to study the Effect of Negative-Pressure Dressing on Healing in Wounds Covered with Split-Skin Grafts

INTRODUCTION: Split-skin grafting is a technique used extensively in plastic surgery for coverage of wounds as also as a part of various reconstructive procedures. Hence, it takes every available knowledge of the phenomenon of graft take and every possible refinement of the technique to ensure best possible results. The present day conventional techniques of skin grafting are fraught with adversaries of suboptimal graft take due to a less-than-ideal graft bed, difficulty in apposing the graft to the bed, shearing between the graft and the bed and seromas or hematomas under the graft. Vacuum assisted closure of wounds first described and popularized by Fleischmann in a series of papers in 1990s has ever since been used in the management of wounds in various clinical settings with mixed results. Several animal experiments4 have recognized that sub-atmospheric pressure increases local blood flow, clears the wound surface of the discharges, reduces bacterial load, decreases edema, increases rate of granulation tissue formation, produces mechanical stress within the tissue resulting in protein and matrix molecular synthesis and enhance epithelialisation. The technique of vacuum assisted closure (VAC) has also been tried on split-skin grafts and has shown to increase the graft take rates.5 However, there are few comparative studies between the conventional dressing and vacuum assisted closure on skin grafts which include a wide variety of clinical settings and measure the graft take as a continuous data. The present study was undertaken to fill this void so as to establish the effect of each method in comparison with one another clinical terms. AIMS AND OBJECTIVES: Aims and objectives of the study are: 1. To know whether vacuum assisted closure affects the amount of take of a split skin graft. 2. To know whether vacuum assisted closure affects quality of the grafted skin. MATERIALS AND METHODS: The study was conducted at Christian Medical College Vellore. Ethical clearance was obtained from the Institutional Review Board. Consecutive patients undergoing split-skin grafting for any reasons who were consenting for the study were enrolled excluding those with known bleeding tendencies. The patient characteristics, the nature of wound, its size and the tissue at the floor of the ulcer at the time of skin-grafting were noted. Patients were randomized into study and control groups using an open list of computer-generated random numbers. After the split-skin graft was laid and secured as necessary, the control group received a dressing consisting of a Vaseline gauze, cotton pads and cotton bandage (for limbs) or elastic adhesive bandage (for trunk) in that order from deep to superficial. In the study group, vaseline gauze was placed on the graft, on which a low-density polyurethane foam of one and half inch thickness cut to the shape of the graft was placed. A flexible transparent plastic tube of 5mm inner diameter and 1meter length was perforated at sides near one end and the same was inserted into the foam by making a shallow slit in the latter. The whole assembly was covered by a broader transparent adhesive film (opsite) whose edges were sealed to the normal skin surrounding the dressing so that the dressing is isolated from the environment except through the lumen of the plastic tube. The tube was then connected to a continuous wall suction of 80 mm Hg when the patient was shifted from the operation theatre. Effective creation of negative pressure was confirmed by watching for the collapse of the foam and absence of gushing sound of air leak into the system. Splinting and/or elevation of the grafted part was done when deemed necessary in both study and control groups. RESULTS: A total of 72 split skin grafts were put on 64 patients. Forty three of them were males and twenty nine were females. Half the patients were cases and half were controls. Mean age of the patients in controls was 34.31 (range: 16-77) years and in cases was 35.69 (Range: 2-69) years. Indications for skin grafting (table 1), tissue at the graft bed at the time of grafting (table 2) and median size of the grafted area (table 3) were comparable between the two groups. CONCLUSION: Vacuum assisted closure improves the quantity of graft take and the quality of the grafted skin and hence should be used particularly when the graft bed and/or grafting conditions seem less-than-ideal for a complete graft take. Negative-pressure dressing can be assembled using locally available materials thereby reducing its cost