Analysis Of The Adjacent Segment Degeneration After Lumber Dynamic Fixation

Background： With increasing stress on our routine life,incorrect sitting posture and heavy physical activity haveaccelerated lumbar degeneration. Lumbar disc herniation, mainly forlow back pain, is becoming a common and frequently-occurring diseasein spinal surgery. Some scholars defined lumbar disc herniation asfollows: a disease with low back pain as its main manifestationcaused by nerve root compression after the annulus rupture ofherniated nucleus.It suffers patients in their work and life, evencausing disability. Most patients can get good results afterconservative treatment. Surgical treatment becomes the mainalternative treatment when conservative treatment failed.The keystep of surgical treatment is to remove the herniation disc anddecompress the nerve roots completely. But the mere removal of thedisc, it will disrupt the normal physiological structure of thelumbar spine, resulting in lumbar instability, recurrent lumbardisc herniation and other complications and secondary surgery,whichwill Increase pain and economic burden of patients.With the advancesin spine surgery techniques and the improvements in spinal fixationdevices, spinal fusion surgery can rebuild lumbar stability effectively and becomes the main method of treatment of lumbar discherniation.However, clinical follow-up after surgery and basicresearch revealed that spinal fusion surgery will increase thestress of adjacent segments, accelerate adjacent segmentdegeneration, and induce complications such as proliferation ofsmall joints, even disc degeneration and recurrent disc herniationand often require secondary surgery. It brings patients greatsuffering and economic burden.Therefore, that how to reducepostoperative adjacent segment degeneration (ASD) andcomplications becomes a research hotspot. Lumbar dynamic fixationsystem provides an effective solution.this method, anothermilestone in the history, not only retains the activity of surgicalsegments, reduces the load on the adjacent segments, rebuilds thestability of the lumbar spine in the meantime, and are more suitablefor the principle of lumbar spine biomechanics.Objective:To explore lumbar K-rod screw rod dynamic fixationsystem on the adjacent segment degeneration treatment of lumbar discdisease by comparing the preoperative, postoperative and follow-upimaging data of patients with lumbar disc herniation，and alsocomparing with the fusion group，.Methods：Since December2010, our spine surgery has completeda total of50cases of lumbar non-fusion surgeries.There were17 cases of postoperative patients which were follow-up over oneyear.Lumbar JOA score of preoperation, postoperation and follow-upwas used to calculate symptom improvement rate, calculated asfollows: improvement rate=(postoperative score-preoperativescore)×100/(total score-preoperative score). We take laterallumbar spine films, lumbar extend-flex films and MRI as a routineexamination of all preoperative patients;3days postoperation madelateral lumbar spine films;17cases of postoperative patients morethan one year accepted MRI of lumbar, lateral lumbar spine filmsand lumbar extend-flex films.The imaging data would eventually becollected and compared:1.Measuring the operation section andadjacent segmental intervertebral disc height and theintervertebral angle.Measurement methods: all patients in ourhospital, under the same DR taking relax recumbent posture shootinglumbar lateral slice, intervertebral height is equal to theintercellular space of vertebral body height and leading edgetrailing average height;intervertebral angle was a angle betweeninferior and superior edges of the adjacent vertebrae.2.In MRIimaging of preoperative and follow-up, we compared the signal ofsurgical adjacent segment vertebral gap (black disc change).3.17cases of strong fixed lumbar surgery patients,who were taken thesame method to measure the preoperative and postoperative1year surgery adjacent intervertebral height and angle of the section,are selected to compare with patients with dynamic fixation.Results：Symptom improvement rate of patients was calculatedby JOA score had a significant improvement.Instability are notobserved in lateral lumbar spine films and lumbar extend-flex filmsin follow-up period.Preoperative, postoperative and follow-upimaging contrast results:1.Intervertebral height andintervertebral angle of adjacent segments slightly decreases,butless than the degenerative standard, compared with the preoperativedisc space height decreased>3mm, disc space angle change>5°.2.Insome patients, preoperative MR showed "black disc" between adjacentsegments,and reviewed MRI showed that intervertebral degenerationdidn’t aggravate, some patients with intervertebral degenerationimproved.3. Compared with strong fixation group,the intervertebralheight of adjacent segments in dynamic fixation group changed less,but no statistical difference in intervertebral angle change.Conclusions：The postoperative symptoms of patients with K-rod dynamic fixation system can be obviously improved.Compared withfusion surgery, this system can provide the stability,to a certainextent, preserving the movement function of operation segment. Atthe same time,this system can reduces the stress of the adjacentsegments,and delay the degeneration.Even the discs can repair themselves.