Degenerative Spinal Diseases: Clinical And Basic Science Study

Objective In this seris of study, including: (1) To evaluate the long-term clinical outcome and affecting factors of degenerative lumbar stenosis. (2) To assess the outcome of two methods for stabilization and fusion: posterolaterial fusion (PLF) and posterior lumbar interbody fusion (PLIF) for spondylolisthesis. (3) To explore the possibility of reestablish segment stability and anatomy by using allografmg of intervertebral disc. Methods:1. Lumbar stenosis: (1) A retrospective study was carryed out in 46 consecutive patients with lumbar spinal stenosis underwent decompressive fenestration by undermining enlargement of lumbar canal. (2) A series of 132 consecutive patients who underwent decompressive surgery were included in this study, radiographic evaluation was used to determine the constriction of spinal canal. Clinical function pre and post-operation were determined using JOA score. (3) Twenty-eight consecutive patients with degernerative lumbar spondylolisthesis(I ° ) and spinal stenosis were retrospectively studied. (4) Seven fresh human cadaver specimens from lumbar 1 to sacrum were used in this study. The graded fenestrations and discectomies were done and the ranges of motion were determined in three-dimensions.2. Lumbar instability: (1) There were 67 cases in this series, 32 cases in posteriolaterial fusion group and 35 cases in posterior lumbar interbody fusion group. (2) Nine fresh human cadaver specimens from LI to sacrum were tested in flexsion-extension, lateral bending and axial rotation with 8 Nm moment. (3) The ranges of motion were determined by stereophotogrammetry, defferent surgical conditions were determined respectively.3. Intervertebral disc allografting: (1) The change of radiograph, pathology,biochemistry and biomechanics were determined in autograft, fresh- and frozen-allografts, respectively. (2) A total of eight cases were included in this study, the degenerative disc was excised with anterior approach, after removal of the disc, a preserved frozen disc of most compatible size positioned into the slot. No internal fixation was used in all of cases. Results:1. Lumbar stenosis: (1) Forty of the 46 patients had good results, and the remaining 6 patients had fair results. No patient reported worsening of symptoms postoperatively. Average operative time was 1.5 hours with blood loss 220ml. Complications included two dural matter tears, one nerve root injury, but these were improved with in six months postoperatively. (2) The range of follow-up from 48 to 142 months with an average of 78 months. Of these 132 patients, 53 patients (40.2%) had excellent results, 57 (43.2%) good, 18 (13.6%) fair and 4 (3%) poor. During the follow-up period, three of 11 degenerative spondylolisthesis patients underwent reoperation, all consisting of fusion and instrumentation. (3) Twenty-eight patients were available for review at two years follow-up and twenty-five patients were available at a range of follow-up from 4 to 12 years, average follow-up was 6.8 years. Clinical outcome was excellent to good in 89.8% and 96% at 2 years and 6.8 years, respectively. Preoperative lower limb pain score was statistically decreased at 2 years and 6.8 years follow-up. Preoperative back pain score was also decreased statistically at 2 years follow-up, but reversed at 6.8 years follow-up. There was no significant difference between pre- and post-operative radiographic measure of spondylolisthesis severity, disc height and sagittal motion statistically. There were three cases with complication, and 3 cases with reversed operation. (4)After the multiple fenestrations, the sagittal ranges of motion at L4-5 increased by 18% in AP, and 16% in vertical translation under the flexion loads. At L5S1, the motion increased by 19% and 45% respectively. After both fenestration and discectomies, the ranges of motion in the sagittal plane increased by 28%(horizontally) and 71%(vertically) at L4-5;14% and 166% at L5S1. The motion increases were statiscally significant(P<0.05) in vertical translations. However, after the graded surgeries, no significant motion were found in the lumbar segments during lateral bending as well as axial rotation.2. Lumbar instability: (1) The follow-up period was 2-10 years, the average was 5.8 and 4.5 years in PLF and PLIF groups, respectively. The means of operative time were 187 min in PLF group and 248 min in PLIF group. Meanwhile, the means of bleeding were 680 ml in PLF group and 945 ml in PLIF group. There was no significant difference of clinical outcome based on JOA scoring system between PLF and PLIF groups, but low back pain was improved 72.4% in PLF and 88.2% in PLIF (p=0.042). Bone union was 74.8% in PLF group and 94.3% in PLIF group, respectively (p=0.011). The correction of slippage was statistically significant in both groups (p<0.05), but the loss of correction at the last follow-up assessment was better in PLIF group (p<0.05). There were 19 and 11 complications of various situations in PLF and PLIF groups, respectively. (2) By resecting L4 laminar, partial L4-5 facet joint and discectomy, the ROM of L4-5 was increased significantly in all six motions. Compared with the intact spine, ROM were significantly reduced in flexion-extension by CD implant, but there were no significant changes in lateral bending and axial rotation. Both CD-graft and CD-TFC yielded high valves for stiffness in flexion-extension, lateral bending and axial rotation compared with the intact lumbar spine, even after fatigue loading test, the ROM of L4-5 did not increase significantly. The ROM of L4-5 in axial rotation with CD-TFC was smaller than that with CD-graft.3. Intervertebral disc allografting: (1) Radiograph demonstrated gradual loss of intervertebral disc height in the early stage postoperatively, the disc height was still kept 64.9% of its original height at 24 months postoperatively. There was a mild immune rejection in the interface between allograft and recipient vertebral body from 2 to 8 weeks postoperatively. However, the allografting intervertebral disc showed evidence of "Human-aging-like" progressive disc degeneration 2years after transplantation. Metabolic function of frozen allografting intervertebral discs was not as normal as control, but was still maintained in a new level. Biomechanically, hypermobility of allografting segment was observed in flexion-extension, lateral bending and rotation at 2 months, then, there was a revision of hypermobility at 6 months postoperatively. (2) The following time was 12-24 months, all grafted discs were survived and no dislocations and subluxations. Disc height decreased, but still maintained 76.2% at 24 months follow-up, meanwhile, the flexion and extension of grafted disc was in average 9 degree at 24months. According to the standard of JOA scores, it raised from 8 points pre- to 13.2 points post-operatively. The patient with tetraparalegie was improved from Frankel B pre- to Frankel D post-operatively in neurologic function. MRI showed the grafted discs had normal Tl and T2 weighted images in late follow-up. Conclusion:1. Lumbar stenosis: (1) The multilevel fenestration with enlargement of spinal canal appears to be an efficacious and safe management in the elderly with lumbar spinal stenosis. (2) Multiple lamonotomy is a reliable procedure for management of lumbar spinal stenosis. There was a significant correlation between good result and lumbar spinal stability in long-term follow-up. Other prognostic factors were age and surgical technique. (3) Decompressive lamonotomy alone is an effective method in management of grade I degenerative lumbar spondylolisthesis with spinal stenosis. Long-term clinical outcome was correlated with surgicaltechnique, progression of natural history and post-operative instability. (4)Thepresent results demonstrate that multilevel fenestrations and discectomies affect lumbar spinal stability in flexion, but have not effect on the stability of the lumbar spine in lateral bending or axial rotation.2. Lumbar instability: (1) Comparing with PLF procedure, PLIF procedure had the disadvantages of longer operative time, more tissue trauma. On the other hand, the advantages of PLIF procedure had a high rate of bone fusion, lower rate of...