Objective To explore effective substances and methods for prevention of peridural adhesion. Methods Laminectomy was performed on the 5th lumbar segment in 64 rabbits, which were equally divided into 4 groups. The duramater (12 mm×6 mm) was exposed. The exposed duramater was left uncovered in Group A; the exposed dura mater was covered with sodium hyaluronate jel (high molecular weight, 1 ml) in Group B; the lamina repair was performed with the autologous spinous process in Group C; the lamina repair was performed with the sodium hyaluronate jel filling and the autologous spinousprocess in Group D. The specimens were observed grossly and histologically at 2, 4, 6 and 8 weeks postoperatively. The computed imaging analysis on the epidural adhesion was also performed at 6 weeks postoperatively. Results ①The gross anatomical evaluation: Severe peridural adhesion was formed in Group A, less adhesion formed in Groups B and C, but no obvious adhesion formed in Group D. ②The area percentage of the epidural scar: The area percentage ofthe epidural scar was 15.89%±1.88% and 13.94%±1.89% in Groups C and D respectively, which were significantly lower than those in Groups A and B (22.66%±2.89% and 20.70%±2.82%,Plt;0.05). ③The density of epidural scar: Thedensity of the epidural scars were 42.03%±7.36% and 36.50%±9.08% in Groups B and D, which were significantly lower than those in Groups A and C (63.73%±6.06% and 52.11%±4.10%，Plt;0.05). Conclusion The high molecular weight sodium hyaluronate jel filling combined with the lamina repair using the autologous spinous process has the best preventive effect on the peridural adhesion after laminectomy.
Objective To study the effect of the allogeneic bone sheet that has been treated by the freezedrying and radiation sterilization in preventing the epidural adhesion after laminectomy in sheep. Methods Laminectomy was performed on L3,4and L4,5 of 12 adult male sheep. Afteroperation, one site of L3,4 or L4,5was covered by the allogeneicbone sheet in “H” shape after the freeze-drying and radiation sterilization treatment; and the other site was used as a control. The sheep were killed and the specimens were retrieved at 4，8，12，16，20 and 24 weeks after operation to observe the scar formation process. X-ray andCT scan were performed in the segments of L3,4and L4,5at 4 and 24weeks. Results Four weeks after operation, the position and the shape of the allogeneic bone sheet were good in condition, and no lumbar spinal stenosis or compression of the dura was found in the experimental sections. Twentyfour weeks after operation theexamination on the experimental sections revealed that the vertebral canal reconstruction was completed, the allograft was absorbed almost completely, and inosculation with the lamina of the vertebra and the shape of the lumbar spine were good, with no fibroid tissues found in the epidural area. Compared with the control segment, the dura adhesion degree in the laminoplasty segment was significantly decreased (Plt;0.01), and the dura sac remained in a good shape. There was no obvious compression on the dura. Conclusion The allogeneic bone sheet after the treatment of freeze-drying and radiation sterilization can effectively reduce the scar formation after laminectomy and prevent postoperative recurrence of the spinal stenosis.
Objective To investigate the clinical effect of polylactic acid membrane in prevention of epidural scar and adhesion. Methods From July 1998 to April 2000, 62 patients with lumbar disc herniation were randomly assigned into two groups. All were treated surgically with discectomy by fenestration or laminectomy.One group were placed with a thin of polylactic acid membrane covering the interlaminar space(n=32). The thickness of the film was 0.1mm. The other group was blank control(n=30). After 2 weeks of operation, we observed the local and systemic reactions. After 6 months clinical symptoms were revaluated and the degrees of epidural scar and adhesion were determined by CT scans. Results After 2 weeks, we found no adverse systemic reactions in all patients. Wound healing was excellent. No abnormalities of hepatic and renal functions as well as blood for routine were found. Temperature after operation was normal. After 6 months, the curative effects were as follows in experimental group and in control group: excellent in 27 patients and in 24 patients, good in 4 patients and in 4 patients, fair in 1 patient and in 1 patient, and poor in 0 patient and in 1 patient, respectively. There are no significant difference between two groups. The CT scans showed no adhesion between the epidural scar and the dural sac in all patients of experimental group. There existed various extents of adhesion in control group. Conclusion The results demonstrate that the polylactic acidmembrane can effectively prevent the epidural scar adhesion with a good biocompatibility and no toxity. Its clinical application was promising.
In order to find an ideal biological material to prevent peridural adhesion following laminectomy, 30 rabbits were used as animal model, in each of which 2 defects with a size of 1 cm x 0.5 cm were made following laminectomy of L3, L5 spine. One of the defects was covered extradurally with chitosan, gelatin foam or PLA membrane respectively, while the other defect was exposed as control. All of these animals were sacrificed on the 2nd, 4th, 6th, 8th and 10th week after operation, and the extradural fibrosis and adhesion of every animal were evaluated by gross observation and histological examinations. It was revealed that in the chitosan and PLA membrane groups, the extradural tissue was smooth without thickening and there was no fibrous proliferation or adhesion in the epidural cavity, and that in the chitosan group, the growth of fibroblast was restrained but the growth of the epithelial cells was promoted significantly, thus, wound healing was rapid. In the control group and gelatin foam group, obvious extradural fibrosis and adhesion were observed and the extradural space had almost disappeared. Therefore, it was concluded that the biodegradable PLA membrane and chitosan were both an ideal material in the prevention of postoperative epidural adhesion.