Biomechanical Testing And Experimental Research Of The Lumbar Allograft Interbody Fusion Cage

Objective:To develop a new lumbar design fusion cage made of allograft material, and insert it into adult human fresh cadaveric specimens to evaluate the stability and compressive mechanical functions of it.And put it into animal experiment to observe its influence on the fusion process and its transformation during degrading period,to offer basic information for its further developmentand clinical application.Method:①To design the lumbar fusion cage made of allograft material by consulting relative domestic and overseas literatures in recent years.②To evaluate the stability and compressive mechanical functions of the lumbar allograft interbody fusion cage.③The lumbar allograft interbody fusion cage was implanted into intervertebral disc to find out its influence on bone fusion at different phases and reveal the degrading process of the material in spine fusion by gross observation,X-ray,CT,histology,electronic microscope, biomechanical test.compared with normal interbody fusion.Result:①The lumbar Cage was successfully made which was wedge shape and made of allograft material.②The stability and compressive mechanical functions of the lumbar allograft interbody fusion cage meets biomechanical and clinical requirements。③The bone growth wasinfluenced in the early stage of fusion,while at 24w,the Cage have nothing to do with the fusion,the solid bone fusion was achieved in the end at about 36w.The degrading progress was non-lineal.In the early stage of fusion,the main degradation focus on the superficial decomposition,the Cage can keep its basicform.With the proceeding of fusion and degradation speeding up andinternal decomposition by self-catalyse result,but still can keep its basic form at 24w.In 36w the Cage was disassembled and lose its form,the progress of totally degrade need a longer time.Conclusion:1.The allograft interbody fusion cage not only can remain or increase the height of intervertebral space of the lumbar spine,but also can provide enough support and improve the stability of the lumbar spine.The design is distinctive and reasonable.It completely meets biomechanical and clinical requirements.2.The allograft material has good tissue compatibility andwill not result in evident immune reaction.It has no obvious negative influence on fusionprocess.The allograft Cage maintained its shape in the early time,and still enough to keep the structure from collapsing until fusion was achieved in the bone implant area.The degrading progress was non-lineal and need long time to totally degrade.The allograft Cage can anastate and retain the lumbar physiological antecurvature and segmental fusion angle and the anterior and posterior of the intervetebral disc height,can supply enough intension for the whole progress of bone graft fusion,strengthen the stability of pedical screw and rod system and prevent the subsidence and migration of the Cage.It can degrade gradually but need a long time.single Cage central implant combined with pedical fixation can achieve solid interbody fusion,3DR-CT, histology,electronic microscope is an accurate method to observe the interbody fusion and Cage degrading.