Observation Of The Clinical Efficacy Of Isobar TTL Internal Fixation System In The Treatment Of Degenerative Diseases Of The Lumbar Spine

BackgroundLumbar degenerative disc disease is a common disease that causes pain,numbness in the lower back and legs.Surgical treatment may be considered when conservative treatment fails to improve clinical symptoms.Spinal fusion was performed clinically in 1911.After more than 100 years of development,it has become a basic surgical method for the treatment of lumar degenerative disease.However,after lumbar fusion,the fixed segment mobility was lost and the normal motion mode of the lumbar spine was damaged.And the load of the mobility,intervertebral disc and facet joint will increase,which will lead to the degeneration of the adjacent segments.In recent years,dynamic or non-fusion stabilization of the lumbar spine has received increasing attention as a possible alternative treatment of lumbar degenerative diseases.Isobar TTL dynamic stabilization system consists of a diameter rod with an integrated damper component.The damper or dynamic component contain stack s of wear resistant Ti alloy discs that serves as linear elastic "shock absorbers" while restricting axial(±0.2mm)and angular(±2°)ROM.Clinically,it is mainly used for the treatment of patients with single-segment disc herniation or single-segment intervertebral instability.In clinics it is indicated for single or double segment rigid fixations with adjacent segment semi-rigid dynamic stabilization,or single segment dynamic stabilization.ObjectiveTo evaluate the outcomes of Isobar semirigid fixation system for treatment of lumbar degenerative diseases.MethodsForty patients who underwent Isobar TTL stabilization for lumbar degenertive diseases from July2011to January 2018 were retrospectively reviewed.Visual analog scale(VAS)and Oswestry disability index(ODI)were used for assessment of clinical outcomes.Analysis the results of the disc height ratio,ROM and lumbar lordosis on X-ray film.ResultsThe 48 patients were followed up from 3 months to 82 months with an average of 24 months.20 patients were followed up for more than 24 months.VAS score was reduced from 9(1-10)preoperatively to 0(0-5)postoperatively(P<0.001).Preoperative ODI was 85(15.6-100)%,and the postoperative ODI was 2.2(0-51.1)%(P<0.001).At the latest follow-up,a significant decrease of disc height ratio and range of motion was noted at the dynamic fixation level(P<0.005),a significant decrease of the ROM of total lumbar spine(L1-L5)was noted(P<0.005).No differences were found in the lumbar lordosis compared data before operation with the latest follow-up.However,no significant differences were found in the disc height ratio,range of motion at the superior adjacent segm ent compared data before operation with the latest follow-up(P>0.05).There were new signs of degeneration at adjacent levels in 1 patients on X-ray.Reoperation was required in one patient due to adjacent segment disease.Screw loosening was observed in one patient.ConclusionThe Isobar semirigid fixation system showed good clinical outcomes.This system can limit the interaction of fixed segments within a certain range.It has little harmful effect on the upper adjacent segments of fixed segments,and can maintain the height and range of motion of the upper adjacent segments of most patients.The system may have the effect of delaying the degeneration of the adjacent segment.