| Objective: To observe and evaluate the preventive effect of graft of autologous free fascia lata on the epidural scar adhesion in animal model of laminectomy.Methods: 36 healthy adult New Zealand white rabbits(weight 2.5-3.0kg,either male or female)were randomly divided into A and B groups using random number table method.There were 18 rabbits in each group.Group A was the control group(laminectomy),group B was the experimental group(laminectomy,the free fascia lata was used to cover the bone defect area).The model of laminectomy was made: after anesthesia,disinfection and draping the sterile towels,a total of 36 rabbits received the spinous process resection and total laminectomy for the sixth lumbar vertebra which led to a bone defect area of about 0.5cm × 1.2cm.Epidural fat was removed to revel the dural sac.The following treatment was performed in the lamina defect area: In group A,after washing and hemostasis,suture the muscle fascia tissue directly and closed the wound,and no barriers was placed outside the dura mater.In group B,take fascia lata with suitable acreage from the left lower leg.Trim into the appropriate size and peeled and sewn to the upper and lower articular ligament of the surgical segment to fully cover the bone defect area.Then,the washing and hemostasis were carried out and the wound was sutured layer by layer.After awake from the anesthesia,they were caged and fed regularly.Wound dressing and injection of antibiotics were given for three days after the surgery to prevent infection.Observations:1.General observation and hind limb motor function evaluation for experimental animals:daily observation of animal drinking water,intake,defecation,exercise,spirit,wound healing and infection;The Tarlov scoring criteria of spinal cord injury(SCI)was used to evaluate hind limb function of the rabbits before and after the surgery.2.Gross observation: the rabbits were sacrificed at 2,4 and 8 weeks after operation.Recut from the original incision to observe the formation of epidural scar and the degree of adhesion in the laminectomy area of L6 and were graded according to the Rydell scoring criteria.3.Histological observation:The L5-L7 segments including the paraspinal muscles and other tissues of the spine were removed at each time point after surgery.All specimens were fixed,idecalcified and made slices.Then,HE stain was performed.Epidural scar formation and the adhesion of epidural scar and the spinal dura mater were observed under the microscope and graded with Nuss-baum standard.4.Count the number of fibroblasts.Results :(1)Evaluation of hind limb function: the Tarlov score before the surgery,7d and 14 d after the surgery all were grade 5;the Tarlov score of the first day after the surgery,there were 5 rabbits in group A and 5 rabbits in group B appearing lower myodynamia,and the difference was not statistically significant(P>0.05).(2)Visual observation:there were varying degrees of dense adhesion in the rabbits of group A and B according to Rydell score criteria.Obvious adhesion formed in the rabbits of group A in 4 weeks and 8 weeks,but no obvious adhesion were found in the rabbits of group B in 2 weeks.The different degrees of adhesion were observed in the other groups.Intergroup comparison:There was significant difference between group A and group B respectively in the 2 weeks and 8 weeks(P<0.05),while there was no significant difference between group A and group B in 4 weeks(P>0.05).Intra-group comparison: the three different time points were compared reciprocally in group A and B.The difference was statistically significant between the 2 weeks group and 8 weeks group(P<0.05),while The differences were not statistically significant between 4 weeks group and 2 weeks group,4 weeks group and 8 weeks group(P>0.05).(3)Histological observation: Classification according to the Nuss-baum standard score.Intergroup comparison: the difference between A and B groups were statistically significant at 8 weeks(P<0.05);while there was no significant difference at 2 weeks and 4 weeks(P>0.05).The intra-group comparison:There was no significant difference in 4 weeks and 2 weeks group,4 weeks and 8 weeks group in group A(P>0.05),and the difference between 2 weeks group and 8 weeks group was significant(P <0.05).There was no significant difference between 8 weeks and 2 weeks group,8 weeks and 4 weeks group in group B(P>0.05),and the difference between 2 weeks group and 4 weeks group was statistically significant(P<0.05).(4)Counting fibroblasts: Intergroup comparison: There were statistically significant differences between group A and group B at 2 weeks,4 weeks and 8 weeks(P<0.05).The intra-group comparison : The difference was statistically significant of the comparison at 2 weeks and 4 weeks and the comparison at 8 weeks and 4 weeks(P<0.05),while the difference was not statistically significant at 2 weeks and 8 weeks(P > 0.05).There were no significant differences between the pairwise comparison of group B at each time point(P>0.05).Conclusion: After the laminectomy,the endorachis was prone to adhesion with scar tissue.Graft of autologous free fascia has good tissue compatibility and no rejection reaction.It can served as a isolation barrier and prevent the invasion of hematoma,inflammatory cells and fibroblasts.It maintains their inherent biological structure in longer time in the body.As a result,it can reduce epidural scar adhesions effectively. |
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