Free flap transplantation combined with skin grafting and vacuum sealing drainage for repair of circumferential or sub-circumferential soft-tissue wounds of the lower leg.

BACKGROUND: This study is aimed at evaluating the operation techniques and clinical significance of free flap transplantation combined with skin grafting and vacuum sealing drainage (VSD) in repairing severe traumatic extensive circumferential or semi-circumferential soft-tissue defects of the lower leg. MATERIAL AND METHODS: Thirty patients with severe lower leg injuries were treated by free flap transplantation combined with skin grafting and VSD from January 2008 to June 2011. The size of the wounds ranged from 23×8 cm to 44×28 cm and all affected more 70% of the low leg circumferential area. Wounds were complicated by exposure, necrosis, or infection of deep tissues. The wounds were first debrided and covered by VSD. When the condition of the wound had improved (5 to 7 days later), free flaps were harvested to reconstruct damaged tissue and skin grafts and VSD was used to cover granulation tissues around the transplanted flap. RESULTS: Granulation tissues developed and the area requiring flap cover decreased in all 30 patients after debridement and VSD. In 28 of 30 cases, the transplanted flaps grew well without complication. Peripheral necrosis was observed in only 2 cases, which required a second debridement and skin graft. Ten wound areas covered by grafts were left with scattered peripheral wounds, which healed with the help of 1 more skin graft or dressing change. Morphological appearance and functional recovery were satisfactory in all 30 cases. CONCLUSIONS: Initial debridement and the temporary VSD cover followed after several days by free flap transplantation combined with skin grafting and VSD protection is a reliable treatment regimen for traumatic large circumferential or sub-circumferential soft tissue wounds of the lower leg with deep tissue exposure.

Effects of simulated weightlessness on bone metabolism in rats at different ages.

OBJECTIVE: To compare the effects of simulated weightlessness on age-related bone metabolism and on the mechanical parameters of the weight-bearing bones of rats at different ages. METHODS: Two-month-old and 6-month-old rats (8 in each group) were both subjected to tail suspension test for up to 4 weeks, with 2 groups of rats of corresponding ages (n=8) serving as control. The bone metabolism markers, biomechanical parameters of the femurs, along with the growth and mineral contents of the tibia, were respectively measured and compared with those of the controls. RESULTS: The bone formation markers, alkaline phosphatase and osteocalcin levels, dropped drastically in both groups of rats undergoing tail suspension test (P<0.01), which also induced significant hypocalcaemia (P<0.01). Bone material loss of the tibia occurred in both groups of rats receiving the test (P<0.01) whose effect on the volume and mass of fresh tibia was age-related (P<0.05), but the degree of mineral loss was not consistent with calcium loss in rats at different ages. Except for elastic deformation (P>0.05), both structural and biomechanical properties altered significantly after tail suspension test (P<0.01), and the changes of maximum deformation and maximum load were related to the age of the rats (P<0.05). CONCLUSION: The result is an age-related difference in the response of bone metabolism to simulated weightlessness.

Changes of serum MDA and SOD levels in ischemia-reperfusion injuries of the limbs in rats preconditioned with heat stress.

OBJECTIVE: To study the effect of pretreatment with heat stress on ischemia-reperfusion injuries of the limbs in rats. METHODS: Rat models of ischemia-reperfusion injury were established with or without prior heat stress treatment, in which serum malondialdehyde (MDA) level and superoxide dismutase (SOD) activities were measured by means of thiobarbituric acid and nitroblue tetrazolium respectively. RESULTS: Comparison between ischemia-reperfusion group and the control group revealed significantly elevated MDA levels (P<0.01) and depressed SOD activities (P<0.01) in the condition of ischemia-reperfusion injury. Pretreatment with heat stress, however, significantly lowered the elevated MDA levels (P<0.01) and enhanced SOD activities (P<0.01) during ischemia-reperfusion injury. CONCLUSION: Pretreatment with heat stress can enhance the activity of SOD to remove free oxygen radicals in the cells.