Long Term Follow-up Of Lumbar Degeneration Disease Treated By Expandable Interbody Cage

Objectives:In recent years,expandable interbody cage appeared. this lumbar intervertebral fusion device system can be singly used treatment to the lumbar degenerative diseases without assisted pedicle screw fixation. It had many biomechanical advantages that compared with the previous intervertebral fusion device.This study research datum of Long-term follow-up of5years which used expandable interbody fusion cage to treat the lumbar degenerative disease patients in our hospital from2005January-2008January. We used long term follow-up datum of radiological outcome and clinical therapeutic effect by using expandable interbody cage to treat the lumbar degenerative disease, to study biomechanical advantages of expandable interbody cage and long term of changes in radiological outcome and clinical result.Lumbar degenerative diseases are the most clinical common disease in spinal surgery, mainly consists of the follo wings:lumbar stenosis, lumbar herniated disk disease, lumbar degenerative instability disease. Its main reason is due to lumbar degenerative diseases caused by lumbar annulus bulgin, herniated disc, lumbar vertebral hyperplasia degeneration, lumbar vertebral posterior joints degenerative make the corresponding segment shift factors,these factors compressed dural sac and nerve root,then the compression cause the corresponding nerve root dysfunction. patients with the disease to bring huge pain and sufferings, seriously affects patients’ daily life quality and work quality. Most of this kind of disease can alleviate by conservative treatment. When the degenerative lumbar diseases were failure by formal conservative treatment, operation treatment is the best way to treat this kind of disease, The posterior lumbar interbody fusion is now the best effective method for lumbar degeneration and lumbar disease instability, Compression the first key of operation factors is discompression lumbar degeneration of nerve root and cauda equina, restore the intervertebral height and expand the lumbar nerve root foramen, And it give the anterior column with stable and reliable support and increase the operation stability of the spinal segment.in order to obtain good clinical effect Lumbar spinal fusion with the excellent and good rate of biomechanical properties and excellent after operation, become the standard type of operation the treatment of low back pain and neurological symptoms. But in the operation of lumbar fusion, the posterior stabilized structure often must be removed, including the spinous process, interspinous and supraspinous ligaments, ligamenta flava, part or all of the facet joints and lamina, cause lumbar stability is compromised, in this case the best solution is to aid the use of implant reconstruction of the.spinal stability. In recent years, lumbar pedicle screw can stabilize the operational spine in the immediate postoperative operation section auxiliary interbody fusion, for treatment of postoperative high fusion rate is more and more widely used in lumbar disc degeneration and the lumbar spine disease, The early time we used autogenous iliac bone with interbody fusion. but the methods had postoperative complications of bone absorption, collapse of the intervertebral space height loss, etc..In recent years, as a substitute for the traditional spinal fusion medium autologous bone grafting,different shapes and materials of posterior lumbar interbody fusion had used in clinical treatment. Interbody fusion system is designed to make up for the defect bringed by other types of lumbar fusion apparatus:(Dthe operation procedure is tedious, difficult,②using bone mass caused all kinds of problems by during operation.③Spine axial pressure load is caused by autologous bone height decreased interbody bone graft, decreased postoperative intervertebral height, lumbar nerve root canal narrowing, and a series of clinical complications And its main advantages is to enhance the interface stability of intervertebral space and maintaining the height of intervertebral space, promoting bony fusion, reduce the autogenous bone fusion implant absorption leads to advantages of intervertebral altitude loss and relieved discomfort occur. In bone area unwell symptoms of complications such as bone, intervertebral fusion device to achieve bone fusion in lumbar biological factors and operation segment in intervertebral, more closely related to the stability of spine after operation, operation stability is corresponde to segment and intervertebral fusion cage on the shape and surface structure. Clinical research had found many reports about failure and shift of cylindrical cage now, research and Analysis on the causes of cylindrical cage failure in operation were cause by damagede in implantation cage of lumbar posterior structure and stability of the original endplate related organization. box cage due to poor stability itself, the need for additional pedicle screw fixation system, it increased the operation trauma and operation cost. In order to reduce the operation wound and obtain good clinical effect, stand-alone cage is a minimally invasive treatment of lumbar diseases clinicians, become the ideal requirement. expandable interbody cage appearance, is a stand-alone cage without auxiliary posterior fixation on lumbar disease become the clinical methods again. Expandable interbody cage has the following advantages of biomechanics and anatomy:①the main part of expandable interbody cage comprise four lamellar titanium column, there is a spreading screw in it’s rear area, when using the screwdriver to rotationally put the spreading screw forward when the cage can be expanded, the screw can expand the of screw from the rear to the front part of expand cage,. distraction four lamellar titanium metal body, the cage was applied to vertical and horizontal direction, expansion cage to achieve a two-dimensional direction. It can restore the height of the intervertebral space and reach the appropriate opening height, then it can successful recover the intervertebral height, increase the height of intervertebral space11-13mm, Because the expendable cage can be spread the front part to two direction, while the rear part remain height of cage, so the formation of expandable change shape to The former high an rear low formation, this formation can recovery the intervertebral spacea Physiological and morphological state,high to low form, the form can be physiological and morphological recovery after Shima Maehiro narrow, restoring lordosis intervertebral6°～8°, restore intervertebral lordosis6°～8°. expandable interbody cage reservate the bone space, when the cage were expanded, the internal bone volume were enlarged, increases volume from the initial state increased about20%-30%, it can accommodate more bone in the expandable interbody cage, dispersed the compressive stress to vertical average,conductive to the inervertebral fusion.increase the contact area in cage with the original endplate to improve the fusion rate. The expendable cage of surface have exist hydroxyapatite coat,The bioactivity of hydroxyapatite and bone inorganic composition similar to human bone, the hydroxyapatite coating bone guiding ablilty can be combined with the mechanical properties of titanium metal combine well, improve the fusion rate.④Expandable interbody cage implant in the intervertebral space and it was be expanded. Improve the intervertebral rotation torque from the biomechanical mechanism, strengthen the stability of fusion in the intervertebral space.⑤expandable interbody cage surface is continuous zigzag structure. compared with the traditional metal screw shaped cage, the depth of its thread is only1.0mm. With the taping tool, stable structure fusion sawtooth surface shape can be embedded in the tapping plate, cage cannot damage the bony endplate organization, improve the insertion torque of it, and it make sure in Close together Coincide the bony endplate, effectively prevent intervertebral fusion device were backward prolapse possibility,, more conducive to the intervertebral stability, increase pullout strength of the intervertebral fusion cage, prevent the cage shift to the spinal nerve cannal.⑥expandable interbody cage has t small volume, it reduce the destruction of the posterior structure, and easy to implant, it had fewer complications, more in line with the concept of minimally invasive operation.Methods:We follow up the patient of degenerative lumbar disease by treatment with the expandable interbody cage from2005Jan to2008Jan, the follow up method is The outpatient service and telephone and other methods. successful follow-up85patients of operation for more than5years52male,33female; age35to64years, averaged (40.5±3.5) years old. We research t he follow-up of patients with multiple time points before and after operation with A number of indicators of ODI and X ray. By evaluating the ODI score, X ray of image findings, clinical treatment, research expandable interbody cage treat the lumbar diseases long-term clinical effect.2.1observation index 2.1.1general indexes:operation time, bleeding volume, postoperative complications (nerve injury, leakage of cerebrospinal fluid, internal fixation of fracture displacement, nerve root pain).2.1.2clinical efficacy scoring method2.1.2.1Oswestry disability index score system (ODI):The evaluation indexes include pain, ability of daily life, walking, standing, sitting, extracts, functional, sleep, sex, social activities and travel10content, each item has a total of6alternative answers (score from0to5.0express no dysfunction,5points represented obvious dysfunction). If patients are made to answer for all10items, the corresponding cumulative scores of all10projects, the most high score accounted for10of the total (50) percentage, namely:10/50×100%answer tired points; if only answered9project, is:9the cumulative/45×100%, When the calculated using the Oswestry disability index score system with higher scores, patients with Oswestry dysfunction index is higher, the more serious in patients with dysfunction.2.1.3Imaging evaluation:Includes two aspects:the disc height=the former, disc height, average value average height of intervertebral space of lateral lumbar spine X-ray, bone graft fusion rate=bone graft fusion cases number/total bone graft cases x100%.2.1.4fusion rate standard evaluation:to the literature method to judge the fusion rate, Fusion standards:①the extension, flexion X-ray interbody angle less than5°;②Fusion cage around not bright, no offset, fusion segments with continuous trabecular bone, the dynamic radiograph, segments of relative activity of less than5mm; The possible fusion:fusion segments have no continuous trabecular bone by, but in the dynamicradiograph, segments of relative activity of less than5mm; non-fusion suspicious pseudarthrosis, obvious bone resorption. Fusion of visible lighttransmission area or region significantly with (bone graft fusion around 2mm) has an obvious gap between section,dynamic radiograph,segmental activity than5mm.Results:3.1in general results85cases were successfully completed follow-up over5years. male52patients,female33patients, the age ranged from35to64years ago, averaged (40.5±3.5) years old. all the85patients were followed up by telephone the success of the ODI data,through the success of our department for more than5years and imaging data.3.2operation results this group of patients with operation time about35-90min, the amount of intraoperative bleeding about200-450ml. after lying in bed for3-7d, average bed4.5d activities,6-12W waist waist protection, strictly limit the flexion and extension activities.3.3ODI We refer to this group of success of5years of follow-up patients medical records and patient data for statistical analysis. The average preoperative ODI score (38.33±3.11),1weeks postoperation for:(6.18±0.93),three months postoperation for:(8.22±2.56),1year postoperation for (6.93±1.88) and5years postoperation for (6.36±1.31), According to the statistics of paired t test:, preoperative and postoperative1week comparison of the data, the difference has statistical significance (t=87.916,P<0.001). Comparison data preoperation and data of one week,3months,1year,5years after the operation:the repeated measure analysis of variance,5indicators of sphericity test P<0.001, so the Greenhouse-Geisser method is used to analyze the degrees of freedom correction of repeated measurement variance, Repeated measures analysis of variance index(F=5147.895P<0.001), the difference was statistically significant between the5time points. 3.4X ray Imaging analysis this group of85patients, The average preoperative Intervertebral lordosis angle5.12±1.33,1weeks postoperation for:8.45±1.30, three months postoperation for:8.11±1.24,1year postoperation for7.85±1.27and5years postoperation for7.70±1.26, According to the statistics of paired t test:, preoperative and postoperative1week comparison data, the difference has statistical significance (t=-85.732,P<0.001),. Comparison data of preoperation and data of one week,3months,1year,5years after the operation:the repeated measure analysis of variance,5indicators of sphericity test P value of less than0.001, so the Greenhouse-Geisser method is used to analyze the degrees of freedom correction of repeated measurement variance, Repeated measures analysis of variance index(F=3258.207, P<0.001), the difference was statistically significant between the5time points. The average preoperative the height of Intervertebral space12.35±0.62,1weeks postoperation for:13.10±0.48,three months postoperation for:12.91±0.49,1year postoperation forl2.79±0.49and5years postoperation for12.71±0.51, According to the statistics of paired t test:, preoperative and postoperative1week data comparison of the (t=-14.498,P<0.001), the difference has statistical significance. Comparison data of preoperation and data of one week,3months,1year,5years after the operation:the repeated measure analysis of variance,5indicators of sphericity test P value of less than0.001, so the Greenhouse-Geisser method is used to analyze the degrees of freedom correction of repeated measurement variance, Repeated measures analysis of variance index (t=72.166,P<0.001), the difference was statistically significant between the5time points. The average preoperative the height of intervertebral foramen16.74±0.85,1weeks postoperation for:23.18±1.15,three months postoperation for:22.33±1.07,1year postoperation for21.76±1.04and5years postoperation for21.22±1.06, According to the statistics of paired t test:, preoperative and postoperative1week data comparison of the(t=-42.692P<0.001), the difference has statistical significance. Comparison data preoperation and data of one week,3months,1year,5years after the operation:the repeated measure analysis of variance,5indicators of sphericity test P value of less than0.001, so the Greenhouse-Geisser method is used to analyze the degrees of freedom correction of repeated measurement variance, Repeated measures analysis of variance index(F=1310.224,P<0.001), the difference was statistically significant between the4time points.3.5intervertebral fusion rate patients were followed up for1years and intervertebral fusion rate was100%,5year fusion rate was100%. X-ray is not found with adjacent segment degeneration of intervertebral disc.3.6complications no nerve and cauda equina injury during the operation,no cerebrospinal fluid leakage occurred in the operation.1cases were followed up after the two months expendable cage embedded above the vertebral body collapse of the intervertebral space,, main symptom is pain in the lower-back pain and no symptom of nerve root, lumbar protection for24weeks after the lumbar symptoms gradually disappear, after12months of follow-up, lumbar X-ray showed bone bridge in the operation of anterior vertebral, patients symptoms disappeared.1patients after1months postoperation show operational section infection symptoms, as early as the lumbar pain, followed by two lower limbs radioactivity numbness, review of lumbar CT,we can see that upper and lower vertebral body had obvious bone destruction, expendable cage is embedded into the vertebral body, no abscess formation, treatment method is sleep in bed and antibiotics about6weeks, we check ESR, C reactive protein were normal, gradually get up in three months after easing symptoms, waist, residual mildlower extremity numbness symptoms. Lumbar symptoms was releasebut residual mild lower extremity numbness symptoms. ConclusionsExpandable interbody cage treat lumbar degenerative diseases, it has the advantages of simple operation, less trauma, good curative effect. Without auxiliary posterior pedicle screw fixation can achieve the lumbar stability reliable, patient can perform early functional exercise, reduce long-term bedridden due to postoperative complications. According to the findings of a long-term follow-up study, expandable interbody cage can keep the height of intervertebral space better long-term, the reconstruction of the intervertebral lordosis, Lumbar biomechanical function recovered well, intervertebral fusion rate is high, Long term follow-up showed that the postoperative curative effect was excellent. No severe complications were found in Expandable interbody cage of treatment and with good clinical application prospect to treat lumbar degenerative diseases.