The Effect Of Anular Suture After Mimetic PELD In Mechanical Properties

Percutaneous Endoscopic Lumbar Discectomy(PELD) is the treatment of Lumbar disc herniation(LDH),which is common and effective operation.But with more outstanding and intervertebral disc degeneration of nucleus pulposus,the complications is becoming awkward. Most scholars believe that disc integrity damage is material cause for the in situ herniation. 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 or improvement of intervertebral disc degeneration. Establishing experimental model by acupuncturing suzhong swine lumbar fiber ring, Load testing on complex suture group with other groups after repair of damaged fiber ring, record the mechanical changes.Objective(1). Simulation of postoperative PELD intervertebral disc damage models, in vitro biomechanics changes along with suture AF. In vivo studies to assess the effect of direct anular repair on subsequent degeneration of intervertebral discs (IVDs).(2). To assess whether a new suturing method could provide sealing effect on IVD after discectomy, and influence degenerative process of IVD,comparing with the simple suture method. According to the results of microcomputer control electron universal testing machine(METM) whether a simple suture has theoretical significance.MethodsSelect six 9-month-old zuzhong swines, divided them into four groups, blank group (group A), control group (group B), complex suture group (group C) and simple suture group (group D). Group of B, C and D injury the annulus fibrosus after posterolateral exposure in the vertebral canal structure, according to the export of neural position determine intervertebral disc position. The 2.5 mm Kirschner wire was inserted into the disc 12 mm depth,control residence time 3 minutes before the needle was pulled out. 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 Improved complex suture (ICS) as well as Group D using ordinary surgical suture to deal with broken fiber ring gap. Group C and D use METM to fix on both ends of the stitches, under uniform tension 50 N in complete four surgical knot, to ensure knot unify. 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).After loading, 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). After loading,C, D group can not see suture fracture or slippery knot, stitching looks good.(3). 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.(4). Through statistical analysis found that complex suture group (C group) and simple suture group (group D) and paired T test between the control group (group B) had significant difference (P< 0.05), leakage pressure is significantly higher than group B.(5). Simple suture group (group D) and the blank group (group A) paired T test were significant difference (P< 0.05), pressure leak obviously less than physiology fiber ring damaged pressure;Complex suture group (group C) and the blank group (group A) paired T test were no significant difference (P> 0.05),though group C is not modified as physiological status of AF, when the numerical is superior to the rest of the two groups.(6).Group C andgroup D paired T test are significant differences (P< 0.05), group C in situ broken pressure value was obviously higher than that of group D.Conclusions(1). AF injury can cause slight load when the NP herniation.(2).ICS can provide better mechanical stability for intervertebral disc, compared with the simple suture group can withstand higher axial load and not burst.(3).simple suture method can obviously improve the biomechanical characteristics of the intervertebral disc, and the operation is more convenient.(4). Two suture circumstances when no suture fracture or slippery knot, Maxon stitches can be used to maintain integrity on the AF defect.