Minimum Eight-year Follow-up Of Lumbar Disc Herniation Treated With Nonfusion Dynamic Stabilization System

Background:Lumbar intervertebral disc herniation is a common and frequently occurring disease in spinal surgery.The main clinical manifestation is low back pain combined with radiolurgic pain in lower extremities.Most of the patients can be relieved by conservative treatment,while some still need surgical treatment.The intervertebral foramen in the vertebral Fusion between(Transforaminal Lumbar Interbody Fusion,TLIF)is one of the commonly used surgical treatment of Lumbar degenerative disease.Most studies have shown that clinical symptoms can be effectively alleviated.However,after fusion,lumbar motor function was lost and stress load of adjacent segments was increased,leading to degeneration of adjacent segments.With the rapid development of medical technology,non-fusion technology has been gradually applied to treat degenerative diseases of the lumbar spine.This surgical method retains the motor function of the spinal segment and avoids the degeneration of adjacent segments after spinal fusion.Dynesys system is one of the non-fusion techniques in the posterior approach,which is based on a pedicle screw that can bear the load from different directions and the plane of motion of the fixed section and retain a certain ROM.In theory,Dynesys for treating degenerative diseases of the lumbar vertebrae can preserve the motion of the lumbar vertebrae and reduce the occurrence of adjacent-segment degeneration.Objective:To investigate the long-term effect of Dynesys technique in the treatment of single segment lumbar disc herniation.Methods:The clinical data of single-segment lumbar disc herniation treated with Dynesys dynamic internal fixation in our hospital from July 2008 to July 2011 were retrospectively analyzed.Among them,53 patients(Dynesys group)were treated with Dynesys non-fusion technology,and 47 patients(TLIF group)were treated with lumbar fusion during the same period.Clinical and imaging data,including visual analogue pain score(VAS),Japanese orthopaedic association score(JOA),and Oswestry dysfunction index(ODI),were collected before and at the last follow-up.Intervertebral range of motion(ROM),intervertebral space height,Pfirrmann classification of intervertebral disc degeneration at the operative segment and adjacent segments.The long-term complications,such as disc reherniation and failure of internal fixation were counted.Results:(1)All 100 patients were followed up completely for 8.2 to 9.3 years,with an average of 8.8 years The VAS score,ODI score and JOA score of lumbago and leg pain at the last follow-up were significantly improved compared with those before surgery(P<0.05).VAS score,ODI score and JOA score were not significantly different between the two groups before and at the last follow-up(P>0.05)(2)Dynesys group:at the last follow-up,the height of intervertebral space at the operative segment[(12.02±1.74)mm]was higher than that before surgery[(11.79±1.89)mm],but the difference was not statistically significant(P>0.05).At the last follow-up,the intervertebral activity of the operative segment decreased from[(6.98±1.98)°]to[(3.87±1.33)°],and the difference was statistically significant(P<0.05).At the last follow-up,the height of intervertebral space in the adjacent segment of the hand[(11.92±1.85)mm]was lower than that before the operation[(12.13±1.63)mm],but the difference was not statistically significant(P>0.05).At the last follow-up,there was no significant difference in the intervertebral activity of adjacent segments from[(7.51 ±1.99)°]to[(8.04±1.62)°(P>0.05).(3)TLIF group,the height of intervertebral space in the operative segment[(12.55 ±1.76)mm]at the last follow-up was higher than that before surgery[(12.34±1.82)mm],but the difference was not statistically significant(P>0.05).At the last follow-up,the intervertebral activity of the operative segment decreased from[(7.11±1.94)°]to 0°(P<0.05).At the last follow-up,the height of intervertebral space in the adjacent segment of the hand[(12.15±1.68)mm]was lower than that before the operation[(12.57±1.58)mm],but the difference was not statistically significant(P>0.05).At the last follow-up,the intervertebral activity of adjacent segments increased from[(7.38±2.04)°]before surgery to[(9.53±2.17)°],with statistically significant difference(P<0.05)(4)At the last follow-up,Pfirrmann grading showed a total improvement rate of 5.7%(3 cases),no significant change rate of 83.0%(42 cases),and degeneration aggravation rate of 15.1%(8 cases).In the TLIF group,the total improvement rate of adjacent segment was 2.1%(1 cases),no significant change rate was 44.7%(21 cases),and degeneration aggravation rate was 53.2%(25 cases).The difference between groups was statistically significant(?2=16.457,P<0.05)(5)During follow-up,1 patient in the Dynesys group had a recurrence of disc herniation,and 8 patients had adjacent segment degeneration.In the TLIF group,there were 2 cases of screw fracture,2 cases of screw loosening,and 25 cases of adjacent segment degenerationConclusion:(1)Dynesys dynamic neutralization system for the treatment of single-segment lumbar disc herniation has a satisfactory long-term effect,which is comparable to the clinical effect of the TLIF group(2)Compared with the TLIF group,Dynesys dynamic neutralization system has the advantages of less surgical trauma,shorter operation time,less blood loss,and shorter hospital stay.Patients can get out of bed early,which is more conducive to rapid recovery of patients.(3)Compared with the TLIF group,Dynesys dynamic neutralization system can maintain the stability of the spine,reduce the abnormal activity of the fixed segment,retain the partial activity of the fixed segment[(3.87±1.33)°],reduce the stress load of the fixed segment and the adjacent segment,and delay the degeneration of the adjacent segment.