The Animal Study Of Repairing The Damaged Annulus Fibrosus By Suture Technology After Percutaneous Endoscopic Lumbar Discectomy

Percutaneous Endoscopic Lumbar Discectomy(PELD) is one of the mainly minimally invasive surgery for treating Lumbar Disc Herniation which become more and more popular recently. Compared with the Open Discectomy(OD),it has the adventages that include of less postoperative pain, less bleed, shorter hospital stay, and it also has the good clinical outcomes. But the recurrence rate is one of the limitations, some scholars statistics it can reach up to be 15%.The postoperative complication of PELD is the defect of damaged annular fibrosus do not be repaired. Cauthen’s studies have shown that direct fiber reconstruction by suture can prevent Nucleus pulposus(NP) herniating. However the lack of experimental data demonstrate the change of mechanical properties. Establishing experimental model by acupuncturing su zhong swine lumbar fiber ring and simulating the operation, Load testing on complex suture group with other groups after repair of damaged fiber ring,record the mechanical changes.Objective(1). Simulating of postoperative PELD intervertebral disc damage models, observing the biomechanics changes along with suture AF in vitro.(2).Via in vitro experiments compare the mechanical properties after simple suture and complex suture,compare the merit and demerit of them.Methods40 lumbar spinal segments were obtained from pigs. Segments were randomly assigned into 4 groups:blank group (group A), control group (group B), simple suture group (group C) and complex group (group D). One 6mm incision was made in Group B,C,D. Group A is normal sham-operated group without destroying the fiber structure. Group B does not handle broken fiber ring structure. Group C using the simple complex suture as well as Group D using complex suture to deal with broken fiber ring gap. After curing, the use of electronic records under the load of force-displacement data, analysis software is used to measure the leakage pressure situation, and four groups of cases mechanics characteristics.Results(1). Afterloading, B, C, D group are visible from the breakage of NP tissue from the fiber ring defect, group A is visible of disc height loss, NP overflowing from squeeze broken fiber ring.(2). Mechanical testing shows group A and group B, group C, group D all have an steep curve when leakage of NP, we can use the software to determine the load stress value of leakage.(3). Through statistical analysis found that simple suture group (C group) and complex suture group (group D) and paired one-way ANOVA between the control group (group B)had significant difference (P< 0.05), leakage pressure is significantly higher than group B.(4). Through statistical analysis found that simple suture group (C group) and complex suture group (group D) and paired one-way ANOVA between the blank group (group A)had significant difference (P< 0.05), leakage pressure is significantly lower than group A.(5) Group C and group D paired one-way ANOVA are significant differences (P< 0.05), group C in situ broken pressure value was obviously lower than that of group D.Conclusions(1).Compared the undamaged annular fibrosus, slight load can cause the NP herniation when annular fibrosus damaged.(2).The AF suture under the percutaneous endoscopic is beneficial to strengthen the mechanical properties.(3).Compare the simple suture, complex suture is better to strengthen the mechanical properties of AF.