Study Of The Biomechanical Property Of Intervertebral Disc After Laser Disc Decompresion & The Possibility Of Silical Gel Discoplasty

Objective:To study the biomechanical change of isolated intervertebral disc and to identify the possibility of discoplasty after laser disc decompression(LDD).Methods:20 pig vertebraes were obtained.The L4,L5 vertebraes and the intervertebral disc between these two vertebraes (the last functional spinal unit FSU)were used.The specimens were divided into three groups:the contral group (in this group the intervertebral disc nuleus was untouched),the laser disc decompression group and the silical gel injected group.Measure and compare the hight,the maximal tranceverse diameter under ON and 500N pressure, the stress and displacement under 100N-500N pressure respectively, before,after LDD as well as after discoplasty in axial.Results:1.Compared with the contral group,the hight of intervertebral disc reduced,the maximal tranceverse diameter of the intervertebral disc increased under 500N pressure. The stress and diplacement increased in the post-LDD group under 100N-500N.2.All index were recovered after silica gel was injected into the intervetebral space(the discoplasty group).3.No silical gel leaking was observed after discoplasty under axial compression. The solidified silical gel distributes evenly in the intervertebral disc.No interspace was observed between the silical gel and the upper and lower end plates.Conclusion:The biomechanical properties of interveterbral disc reduced after LDD.But the biomechanical properties of intervertebral disc recover after two group silical gel injected.. It is possible using two group silical gel discoplasty in lumbar intervetbral disc after LDD.