The utility of the laser Doppler for determining burn depth has been questioned because of problems with technology and methodology. This study prospectively evaluates the ability of a new laser Doppler technique to predict burn healing time. Using the Periflux System 4000 laser Doppler, readings were taken on 305 burns (147 patients) on postburn day 3 or 4. Sixty-six wounds were used to derive a predictive function (phase I) and 152 wounds were used to test the function (phase II). Blood flow dynamics (flux), microvascular dilation capacity of the wounds to beat stress, and flow motion wave pattern (vasomotion) were studied using the laser Doppler, and seven parameters were evaluated to determine their relative contribution to the prediction of healing time. These parameters are hyperemic flux (flux value after heating to 42 degrees C), average hyperemic wave amplitude (AHWA), number of average flux units >100(F100), number readings with wave amplitude 75 (A5), average flux change (AFC), percentage of average flux increase, and relative flow capacity (RFC = AFC/average hyperemic flux). After readings were made, the wounds were observed and divided into two groups: those that healed in less than 14 days and those that healed or were grafted after 14 days. A step-wise discriminant analysis was used to assess the relative contribution of the Doppler-derived measures to healing time prediction. AHWA, F100, and RFC were included in the final discriminant function explaining 72% of the healing time variance (Wilks' lambda value 0.28; p value <0.0001). Predicted outcome = 0.05(AHWA) + 0.31(F100) + 5.0(RFC) - 2.3. With this derived function, there is 94% accuracy in the prediction of burn wound healing time compared with a physician predictive accuracy of 70%.

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Although pressure therapy is the mainstay of treatment for hypertrophic scars, its actual mechanism remains unknown. An in vitro study was designed to investigate the effects of positive pressure on the growth of human scar-derived fibroblasts through its transforming growth factor beta1 (TGF-beta1) secretion. A pneumatic pressure system connecting to a cell culture chamber was designed. Six-well cultured plates with fibroblasts implanted were treated with different pressure settings. Cells were treated with constant pressure 20 mm Hg above atmosphere pressure (group A n = 18) or with 40 mm Hg above atmosphere pressure (group B n = 18) daily for nine successive days. Cells without pressure were treated as the control study (group C n = 6). Each experimental group was divided into daily pressure applied at 24 hours (n = 6), 18 hours (n = 6), and 12 hours (n = 6). Cell counting was performed on the 2nd, 4th, 7th, 9th, 11th, and 14th day after implantation. On day 4, the concentration of transforming growth factor beta1 was measured, and cell doubling time was calculated. Compared with the control group, there was a significant decrease in cell count and the concentration in the 18-hour and 24-hour 20 mm Hg or 40 mm Hg pressure treated group. The cell doubling time was significantly increased in the 24-hour 20 mm Hg or 40 mm Hg pressure treated groups, and the 18-hour 40 mm Hg pressure treated group. (P < .05) Pressure inhibits the growth and activity of human scar fibroblasts, and a higher pressure application can shorten the daily application period. There should be an optimal pressure level corresponding to a daily application period to achieve the most effective results on pressure therapy for scars.

For ORN patients, vascularized iliac bone flap provides more reliable results compared to fibula flap. The merits of vascularized iliac flap include the following: (1) its natural curve mimics the shape of mandible and does not need osteotomy; (2) it offers more volume of bone that matches better to the native mandible to allow later osteointegration as well as faster bony union, due to the nature of being a membranous bone; and (3) it carries more abundant soft tissue to obliterate possible dead space. The only disadvantages are short pedicle and requiring special management of skin paddle, which can be overcome by training in microsurgery.

Appendix has a reliable vascularity and a unique structure for reconstruction of conduit-like organs, and combining its adjacent bowel segments, including ileum, cecum, and colon, during tissue transfer not only increases its length but provides more applications and possibilities for reconstruction of different parts of the body. Removal of the appendix carries minimal morbidity. Our study proved the applicability and reliability of free and pedicled appendix transfer.