A bio-degradable synthetic membrane to treat superficial and deep second degree burn wounds in adults and children - 4 year experience.

INTRODUCTION: A new bio-degradable synthetic membrane was recently introduced to treat second degree burns in adults and pediatric patients. OBJECTIVE: To assess complications and outcomes using this absorbable synthetic membrane to treat second degree burns. METHODS: 229 burn patients, 138 pediatric, with superficial and deep second -degree wounds, treated with the absorbable synthetic membrane (Suprathel®, Polymedics, Denkendorf, Germany) were included in this study. Patients were treated under anesthesia or moderate sedation. The wound bed was prepared by using either rough debridement or dermabrasion excision. After hemostasis, the membrane was applied to the wound with an outer layer dressing of fatty gauze, bridal veil, absorptive gauze and an ACE® wrap. The outer dressing was removed every one to four days, depending on exudate, in order to closely follow the wound through the translucent membrane and fatty gauze layers. After complete epithelialization, the dressing separated and could be removed. The study focused on the need for subsequent grafting, healing time, patient pain level, hypertrophic scarring and rate of infection. RESULTS: All wounds in this study that were treated with Suprathel® healed without grafting. The average TBSA (Total Body Surface Area) was 8.9% (1%-60%). Average time to healing was 13.7 days for ≥ 90% epithelialization with 11.9 days for pediatric patients versus 14.7 days for adults. Throughout the treatment period, the average pain level was 1.9 on a 10-point scale. 27 patients developed hypertrophic scarring in some areas (11.7%). Average Length of stay (LOS) was 6.9 days. The rate of infection was 3.8% (8/229). Failure or progression to full thickness in part of the wounds was 5.2% (12/229). CONCLUSION: In treating second degree burn wounds, this membrane provides a simple, effective solution alternative with good outcomes and less pain than conventional and previously studied treatment options in the same institution. Fewer dressing changes and easier overall management of the wounds contribute to its favorable profile.

L-selectin and leukocyte function in skeletal muscle reperfusion injury.

HYPOTHESIS: Treatment with anti-L-selectin monoclonal antibody will reduce venular neutrophil-endothelial rolling (flux and velocity) and adhesion associated with ischemia reperfusion injury in rat skeletal muscle. DESIGN: Prospective, randomized experimental trials. SETTING: Basic science research laboratory. MATERIALS: Male Wistar rats weighing 109 +/- 5 g (mean +/- SEM). INTERVENTIONS: Gracilis pedicle muscle flaps were elevated and microcirculation was observed by intravital microscopy. Two groups were evaluated: (1) the control group, which received 4 hours of global ischemia, and (2) the experimental group, which received 4 hours of global ischemia, plus treatment with anti-L-selectin monoclonal antibody 30 minutes before reperfusion. MAIN OUTCOME MEASURES: The number of rolling and adherent leukocytes in postcapillary venules were counted in the 2 groups at baseline and at 1 through 5, 10, 15, 20, 30, 45, and 60 minutes of reperfusion. RESULTS: Treatment with the monoclonal antibody to L-selectin significantly reduced the number of rolling leukocytes (flux) at 2 through 5, 20, 30, 45, and 60 minutes of reperfusion compared with controls (P<.05). Use of the monoclonal antibody significantly reduced the number of adherent neutrophils at 5, 10, 15, 20, 30, 45, and 60 minutes of reperfusion (P<.05). There was no significant difference in leukocyte velocity. CONCLUSION: L-Selectin plays a significant role in leukocyte rolling and adherence to venular endothelium in rat skeletal muscle ischemia reperfusion injury.

Single-vessel arteriovenous revascularization of the amputated ear.

Successful single-vessel arteriovenous replantation of a completely amputated human ear is described. This result was followed by an experimental study using a rabbit model, to confirm that an amputated ear could survive replantation with only a single arteriovenous anastomosis. Fifteen animals were placed in one of two experimental groups: Group 1-arteriovenous replantation, no treatment (n = 6); and Group 2-arteriovenous replantation with medicinal leeching (n = 9). All ears demonstrated initial reperfusion of the replantation immediately following microanastomosis. Laser Doppler flow readings in the non-leeched replanted ears fell to zero by 8 hr and, by 12 hr, the non-leeched ears demonstrated signs of necrosis. All the leeched, replanted ears demonstrated perfusion and complete viability at the time of sacrifice. The case report, combined with the results from the experimental study, confirm that single-vessel arteriovenous replantation of an amputated ear is feasible.

Effect of hyperbaric oxygen and medicinal leeching on survival of axial skin flaps subjected to total venous occlusion.

This study evaluates the effect of hyperbaric oxygen and medicinal leeching on axial skin flaps subjected to total venous occlusion. Axial epigastric skin flaps (3 x 6 cm) were elevated on their vascular pedicles in 40 male Wistar rats. Total venous occlusion was achieved by division of all veins draining the skin flap. Arterial inflow was left intact. Animals were randomly assigned to one of five groups: sham (n = 8); control, total venous occlusion only (n = 8); occlusion with hyperbaric oxygen (n = 8); occlusion with leeching (n = 8); occlusion with leeching and hyperbaric oxygen (n = 8). The hyperbaric oxygen protocol consisted of 90-minute treatments, twice daily, with 100% O2 at 2.5 atmospheres absolute for 4 days. The leeching protocol consisted of placing medicinal leeches on the congested flaps for 15 minutes, once daily, for 4 days. Laser Doppler measurements of flap perfusion were recorded preoperatively, postoperatively, and on postoperative days 1 and 3. The percentage of flap necrosis was evaluated on postoperative day 3. Mean percentage necrosis and mean laser Doppler readings were compared between both groups. The flaps in the sham group demonstrated 99 percent survival, whereas the flaps in the occlusion-only group demonstrated 100 percent necrosis. The flaps in the occlusion with oxygen, the occlusion with leeching, and the occlusion with oxygen and leeching groups demonstrated 1, 25, and 67 percent survival, respectively. Sham laser Doppler readings remained within normal limits. Laser Doppler readings in the occlusion-only and the occlusion with oxygen groups decreased to negligible levels on postoperative day 1, and on postoperative day 3 no perfusion was demonstrated. In both the occlusion with leeching and the occlusion with leeching and oxygen groups, there was also a significant decrease in laser Doppler measurements after surgery, but perfusion remained stable throughout the remainder of the study. This study demonstrates that hyperbaric oxygen alone is not an effective treatment for skin flaps compromised by total venous occlusion. The combination of leeching and hyperbaric oxygen treatment of total venous occlusion results in a significant increase in flap survival above that found with leeching alone. It appears that hyperbaric oxygen is effective because of the venous outflow provided by leeching as demonstrated by laser Doppler flow readings.

Assessment of intraneural oxygen tension and blood flow in a mobilized peripheral-nerve model.

Extensive mobilization of injured peripheral nerves is often required to allow a tension-free repair. The purpose of this study was to determine the effect of surgical mobilization and division on intraneural blood flow and oxygen tension in a rat sciatic nerve model. The right and left sciatic nerves were exposed in male Lewis rats Four experimental groups were studied: 1) nerve in situ/intact (n=7); 2) nerve mobilized and intact (n=7); 3) nerve in situ/divided (n=7); and 4) nerve mobilized and divided (n=7). Intraneural oxygen tension and blood flow were measured postoperatively. Mean oxygen tension (mmHg) in mobilized/intact nerves (17.47+/-4.79) was significantly lower than in in situ/intact nerves (38.32+/-5.16) [p < 0.05]. Mean oxygen tension in mobilized/divided nerves (3.10+/-1.25) was significantly lower than in in situ/divided nerves (30.30+/-6.36) [p < 0.005]. Laser Doppler flow (ml/min/100 g) in mobilized divided nerves (11.31+/-1.81) was significantly lower than in in situ/divided nerves (25.60+/-3.31) [p < 0.05]. Laser Doppler flow in mobilized/intact nerves was not statistically significantly different from in situ/intact nerves. Mobilization of the extrinsic blood supply was shown to significantly lower intraneura) oxygen tension and laser Doppler flow in mobilized intact and divided rat peripheral nerves.