Instability in spondylolisthesis

Anteroposterior translation as a sign of segmental instability was documented by traction-compression radiography in the majority of lumbar segments presenting lytic or degenerative spondylolisthesis with normal disc space height. Severity of lower back pain symptoms correlated with the degree of instability, but not with the amount of static spondylolisthetic displacement. Unstable spondylolistheses exhibited decreased viscoelastic behavior with creep, the degree of the vertebral displacement being dependent on the amount and duration of load. Disc degeneration and traction spurs seemed to be factors that may stabilize spondylolisthesis, even at an early age.     

炎性细胞在腹主动脉瘤形成中的作用

目的研究炎性细胞在腹主动脉瘤（ａｂｄｏｍｉｎａｌａｏｒｔｉｃａｎｅｕｒｙｓｍ,ＡＡＡ）组织中的浸润情况及其作用。方法２０例ＡＡＡ患者的动脉瘤组织及４例正常人腹主动脉组织,分别行弹力纤维和胶原纤维的特殊染色、单抗白细胞共同抗原（ＣＤ４５阳性）和巨噬细胞（ＣＤ６８阳性）的免疫组化染色,了解纤维组织的变化及炎性细胞的浸润程度;原位杂交方法观察ＡＡＡ组织中基质金属蛋白酶（ｍａｔｒｉｘｍｅｔａｌｏｐｒｏｔｅｉｎａｓｅｓ,ＭＭＰｓ）之ＭＭＰ９的ｍＲＮＡ表达。结果ＡＡＡ组织均有不同程度的炎性细胞浸润,炎性细胞浸润程度与基质弹力纤维的损伤程度呈平行趋势,正常腹主动脉组织无炎性细胞浸润;原位杂交结果显示２０例ＡＡＡ组织中的巨噬细胞和淋巴细胞均出现ＭＭＰ９ｍＲＮＡ的阳性表达,１３例（６５％）ＡＡＡ组织中的平滑肌细胞出现ＭＭＰ９ｍＲＮＡ的阳性表达。正常腹主动脉组织无ＭＭＰ９ｍＲＮＡ的阳性表达。结论炎性细胞在ＡＡＡ形成中通过复杂的生化、细胞及免疫等过程参与并促进了ＡＡＡ的形成。     

颈椎椎间盘退行性改变与颈椎不稳

探讨颈椎椎间盘退性改变与颈椎不稳定的关系。方法对２６０例怀疑有颈椎疾患的者行Ｘ线及ＭＲＩ检查。在颈椎屈曲／伸展侧位片上测量椎体水平位及成象程度,并根据ＭＲＩＴ２加权像椎间盘信号强度判断其退变程度。结论颈椎的节段性不稳定是颈椎椎间盘退行改变的早期表现之一。     

退行性腰椎不稳发病相关因素的临床研究

目的分析性别、年龄、相应节段椎间盘退变、小关节突骨关节炎以及椎体滑脱与退行性腰椎不稳的相关性。方法行腰椎MRI及站立位过伸过屈侧位片检查,观察L1-S15个运动节段的椎间盘退变、椎间小关节退变以及有无椎体滑脱。腰椎不稳分为前水平位移不稳．后水平位移不稳和角度不稳。椎间盘退变分四度。小关节突退变分为4级。腰椎滑脱分四度。将结果进行Spearman等级相关分析。结果前向水平不稳与椎间盘退变呈正相关,与椎间小关节骨关节炎呈负相关,与椎体滑脱呈正相关;后向水平不稳与年龄呈正相关,与椎间盘退变呈正相关。与椎间小关节骨关节炎呈正相关,与椎体滑脱没有明显相关性。结论退行性腰椎不稳与多种因素具有显著相关性,但腰椎滑脱不一定有不稳。     

Association between decreased disc signal intensity in preoperative T2-weighted MRI and a 5-year outcome after lumbar minimally invasive discectomy.

A total of 39 patients who had undergone microdiscectomy or percutaneous nucleotomy for lumbar disc herniation were examined after a follow-up of 5 years. The overall outcome was satisfactory in 80% of the patients treated, and only 1 (3%) patient had been reoperated during the follow-up. Clinical signs and symptoms of lumbar instability were detected in 10 (26%) patients. All these 39 patients had been examined with lumbar magnetic resonance imaging (MRI) on the day preceding the operation; the presence of disc degeneration was graded as severe, mild or non-existent depending on the visual brightness of the discs on T2-weighted images, as compared to the signal intensity of the lumbar vertebrae. None of the 12 patients with no preoperative disc degeneration in MRI suffered from postoperative clinical signs and symptoms of instability as compared to 10 (37%) of the 27 patients with mild or severe disc degeneration suffering from instability (p = 0.04). Thus, the results of the present study imply that the grade of the disc degeneration in preoperative T2-weighted MR images significantly predicted the occurrence of postoperative clinical instability.     

Lumbar instability: a dynamic approach by traction-compression radiography

Translatory segmental instability was provoked by successive axial traction and compression of the lumbar spine in 117 patients with a known spondyl- or retro-olisthetic displacement. Lateral spot radiography showed an anteroposterior translatory movement of 5 mm or more in 24 of 45 patients with lytic spondylolisthesis of L5, in all of 7 patients with degenerative spondylolisthesis of L4, and in 37 of 65 patients with a retro-olisthetic displacement of L3, L4, or L5. In cases of spondyl- and retro-olisthetic instability the upper vertebra moved posteriorly during traction and anteriorly during compression. Severity of low-back pain (LBP) symptoms did not show any correlation with the degree of the maximal displacement but correlated significantly with the amount of instability both in the case of spondyl- and retro-olisthesis. Traction-compression radiography proved a simple and practical method to diagnose and measure translatory segmental instability even when conventional flexion-extension load failed to provoke any abnormal movement (eg, in the case of spondylolisthesis).     

The relationship between disc degeneration, facet joint osteoarthritis, and stability of the degenerative lumbar spine

Degenerative processes in the disc and facet joints affect the stability of the motion segment. The exact relations among disc degeneration, facet joint osteoarthritis, and the kinematics of the motion segment are not well defined in the literature. Magnetic resonance imaging and functional radiography of the lumbar spine were analyzed to examine the relations among segmental instability, facet joint osteoarthritis, and disc degeneration in patients with degenerative disorders of the lumbar spine. Seventy consecutive patients (mean age, 46 years) had both magnetic resonance imaging and flexion and extension radiographs of the lumbar spine. The lumbar instability was classified into abnormal tilting on flexion, rotatory instability in the sagittal plane, and translatory instability. Translatory instability was subdivided into anterior, posterior, and anteroposterior translatory instability. Disc degeneration as seen on T2-weighted sagittal images was classified into five grades. Facet joint osteoarthritis as seen on axial T1-weighted images was divided into four grades. This study revealed that the kinematics of the lumbar motion segment are affected by disc degeneration and facet joint osteoarthritis. Abnormal tilting movement on flexion and anteroposterior translatory instability both had negative associations with facet joint osteoarthritis. However, anterior translatory instability was positively associated with disc degeneration and facet joint osteoarthritis. Rotatory instability in the sagittal plane and posterior translatory instability were not associated with disc degeneration and facet joint osteoarthritis.     

The relationship between disc degeneration and flexibility of the lumbar spine.

BACKGROUND CONTEXT: A relationship between degenerative changes of the intervertebral disc and biomechanical functions of the lumbar spine has been suggested. However, the exact relationship between the grade of disc degeneration and the flexibility of the motion segment is not known. PURPOSE: To investigate the relationship between degenerative grades of the intervertebral disc and three-dimensional (3-D) biomechanical characteristics of the motion segment under multidirectional loading conditions. STUDY DESIGN/SETTING: A biomechanical and imaging study of human cadaveric spinal motion segments. METHODS: One hundred fourteen lumbar motion segments from T12-L1 to L5-S1 taken from 47 fresh cadaver spines (average age at death, 68 years; range, 39 to 87 years) were used in this study. The severity of degeneration (grades I to V according to Thomson's system) was determined using magnetic resonance (MR) images and cryomicrotome sections. Pure unconstrained moments with dead weights were applied to the motion segments in six load steps. The directions of loading included flexion, extension, right and left axial rotation, and right and left lateral bending. RESULTS: When the MR images were graded, 2 segments had grade I disc degeneration; 45, grade II; 20, grade III; 26, grade IV; and 21, grade V. When the cryomicrotome sections were graded, 14 segments had grade I disc degeneration; 31, grade II; 22, grade III; 26, grade IV; and 21, grade V. Segments from the upper lumbar levels (T12-L1 to L3-4) tended to have greater rotational movement in flexion, extension, and axial rotation with disc degeneration up to grade IV, whereas the motion decreased when the disc degenerated to grade V. In the lower lumbar spine at L4-5 and L5-S1, motion in axial rotation and lateral bending was increased in grade III. CONCLUSIONS: These results suggest that kinematic properties of the lumbar spine are related to disc degeneration. Greater motion generally was found with disc degeneration, particularly in grades III and IV, in which radial tears of the annulus fibrosus are found. Disc space collapse and osteophyte formation as found in grade V resulted in stabilization of the motion segments.     

Intimate relationship between instability and degenerative signs at L4/5 segment examined by flexion�Cextension radiography

Relationship between lumbar disc degeneration and segmental instability has remained controversial. Using instability factors that found close relations with symptoms in flexion–extension radiographic study, their relationship with degenerative findings was examined. More than (≥) 3 mm slip in neutral position (SN), ≥3 mm translation (ST), and ≥10° angulation (SA) at L4/5 segment were defined as instability factors and were applied on 447 patients who had low back and/or leg pain and satisfied inclusion criteria for accurate measurements. Radiologic findings for degeneration were disc height including three groups with different disc heights divided by mean ± 1 standard deviation, length of the anterior spur formation, presence of vacuum phenomenon, and endplate sclerosis. As results, group with SN factor was the oldest in age and the lowest in disc height; in contrast, group with SA was the youngest in age and the highest in disc height. The group with ST showed a mid-standing position in both age and disc height. These findings indicate that instability factors are intimately related to age and disc height. The three different disc height groups showed more anterior slip according to the progression of the disc height diminution. Presence of the apparent spur formation and/or vacuum phenomenon had an intimate relationship with the ST factor. Disc height was the most important in the examined parameters and showed an intimate relationship with age and instability factors. Although the etiology is still unknown, clinical common knowledge, that a diminution of disc height with progressive degeneration had a close relation with anterior vertebral slippage, was firstly confirmed. This study allows comprehensive understanding of segmental instability and is useful for considering surgical indications.     

Effects of aging and spinal degeneration on mechanical properties of lumbar supraspinous and interspinous ligaments.

BACKGROUND CONTEXT: The effects of aging and spinal degeneration on the mechanical properties of spinal ligaments are still unknown, although there have been several studies demonstrating those of normal spinal ligaments. PURPOSE: To investigate the mechanical properties of the human posterior spinal ligaments in human lumbar spine, and their relation to age and spinal degeneration parameters. STUDY DESIGN/SETTING: Destructive uniaxial tensile tests were performed on the human supraspinous and interspinous ligaments at L4-5 level. Their mechanical properties were compared with age and spinal degeneration using several imaging modalities. PATIENT SAMPLE: Twenty-four patients with lumbar degenerative diseases on whom posterior surgeries were performed, with the age ranging from 18 to 85 years. OUTCOME MEASURES: The ultimate load and elastic stiffness as structural properties, the degree of disc degeneration, range of segmental motion, the disc height, disc space narrowing ratio and degree of facet degeneration as the parameters of spinal degeneration. METHODS: Twenty-four supraspinous and interspinous ligaments at the L4-5 level were obtained from posterior surgeries of patients with lumbar degenerative disease. The mechanical tests of bone-ligament-bone complexes were performed in a uniaxial tensile fashion with a specially designed clamp device. The ultimate load and elastic stiffness were calculated as structural properties. The degree of disc degeneration, range of segmental motion, the disc height, disc space narrowing ratio and degree of facet degeneration were examined by using radiographs, computed tomography and magnetic resonance imaging. RESULTS: The average and SD value of ultimate load, elastic stiffness, tensile strength and elastic modulus were 203+/-102.9 N, 60.6+/-36.7 N/mm, 1.2+/-0.6 Mpa and 3.3+/-2.1 Mpa, respectively. A significant negative correlation was found between age and tensile strength (p= 0.02). The specimens with facet degeneration showed lower values in tensile strength and elastic modulus than those without facet degeneration (p<0.04). However, no correlation was found between disc-related parameters and tensile strength. CONCLUSIONS: The mechanical strength of human lumbar posterior spinal ligaments decreases with age and facet degeneration, particularly in the ligament substance.     

Intervertebral mobility in the progressive degenerative process. A radiostereometric analysis

Three separate stages have previously been defined in the progressive degenerative process. The first stage, characterized as temporary dysfunction with early degenerative findings, transforms into a second period of segmental instability evidenced by a resulting deformity. With the deformity the process has reached a late stage of definitive stabilization induced by osteoligamentary repair mechanisms. To test the validity of this three-stage hypothesis, we assessed the intervertebral mobility for the two most-distal lumbar disc levels in 18 adult patients with low back pain, disc degenerative findings and no prior spinal surgery. Each spinal segment was categorized according to grade of disc degeneration: (IA) normal disc height without dehydration; (IB) normal disc height with dehydration; (II) disc height decreased by less than 50%; (III) disc height decreased by at least 50%; and (IV) disc height obliterated. The intervertebral mobility was measured by radiostereometric analysis (RSA) and compared between the categories. With the patient changing position from supine to sitting, the mean vertical translation across the 11 discs categorized as IA was 2.0 mm. A small increase in mean vertical mobility with progressive loss of disc height through the degenerative stages IB (2.2 mm, seven discs) and II (2.6 mm, ten discs) was not significant. Further degeneration to grade III meant a significant mean reduction in vertical mobility to 0.8 mm for the eight discs in that category. No discs were classified as obliterated, category IV. The corresponding values for sagittal translations were 3.0 mm, 3.1 mm, 3.6 mm and 1.7 mm for the four disc categories found. These alterations were not statistically significant. We conclude that intervertebral mobility changes throughout the degenerative process, and a stage of stabilization begins when disc height is reduced by 50%. The segmental mobility status cannot be deduced from the radiographic, degenerative disc stage, since the inter-individual differences in mobility are pronounced for the same disc status. A fully stable situation cannot be taken for granted, even when the disc is reduced by more than 50%, considering the fact that some persisting mobility was seen for most patients in category III. A preceding stage of instability, in the clinical situation proven by a resulting deformity, was not verified in this study.     

Positional MRI changes in supine versus sitting postures in patients with degenerative lumbar spine

INTRODUCTION: Back pain is associated with a degree of alteration in the alignment and movement of the lumbar spine. The purpose of this study is to investigate how the degree of lumbar segmental degeneration affects sagittal changes in the lumbar spine as it shifts from the supine to the sitting (load-bearing) posture. MATERIALS AND METHODS: Thirty patients with chronic low back pain were enrolled (14 male and 16 female patients); mean age 44.5 years. Their lumbar spines were initially investigated by conventional supine magnetic resonance imaging (MRI) followed later by positional MRI in the seated posture. Of the 150 discs studied, 87 were classified as healthy grade 1, 16 as grade 2, 34 as grade 3, and 13 as grade 4. RESULTS: As the lumbar spine was loaded from the supine to the sitting position, the end-plate angles were decreased significantly as the degeneration was increased. There were also significant changes in the anterior and middle disc heights between the supine and the sitting postures irrespective of the degree of degeneration. The overall lumbar lordosis did not significantly change between the two postures. CONCLUSIONS: We have found that the changes in the segmental motion were related to the degree of degeneration. With positional MRI, we were able to demonstrate changes in healthy and degenerative discs in the weight-bearing position. More similar studies are needed to understand the complex kinematics of the lumbar spine.     

Disc degeneration in young patients with isthmic spondylolisthesis treated operatively or conservatively: A long-term follow-up

The purpose of this longterm follow-up was (1) to investigate disc changes in the olisthetic segment in patients treated conservatively, (2) to compare disc changes above the slipped vertebra in conservatively treated patients with those in operatively treated patients, and (3) to establish possible relations of disc changes to the degree of the slip and to subjective back pain symptoms of the patients. The subjects were 227 patients with isthmic L5 olisthesis diagnosed under 20 years of age (mean 13.8 years) with a mean follow-up of 15.4 (range 5–30) years. Of these, 145 patients had been treated with segmental fusion and 82 had been treated conservatively. At follow-up, standing anteroposterior and lateral radiographs as well as flexion/extension views of the lumbar spine were taken. Disc degeneration was graded semiquantitatively: 0 = normal disc height, 1 = decrease of disc height < 50%, 2 = decrease 50%, and 3 = obliteration of the disc. In the conservatively treated patients degeneration of the olisthetic disc was distributed by grade as follows: 0:n = 38, 1:n = 24, 2:n = 14, 3:n = 6. No motion at all was observed in the olisthetic segment in 40 patients (48%) with a mean slip of 30%,, segmental motion of 4°–18° was found in 42 patients with a mean slip of 14%. There was a statistically significant association of the degree of slip to the severity of disc degeneration and non-mobility of the segment. Grade 1 degeneration of the L4/5 disc occurred in 25.6% of the conservatively treated patients and in 32% of 48 patients treated with L5-S1 fusion. This correlated with the severity of the slip, but not with pain symptoms or pathologic segmental mobility at the time of follow-up. Out of 84 patients with L4-S1 fusion, in 17% grade 1 degeneration of the L3/4 disc was observed, and 3 out of 13 patients (23%) with L3-S1 fusion had grade 1 degeneration of the disc above the fusion. The disc changes had no correlation with subjective pain symptoms. It is concluded that the natural course of isthmic spondylolisthesis is associated with disc degeneration and spontaneous stabilization of the olisthetic segment. Fusion operations do not significantly increase the rate of disc degeneration in the adjacent disc above the fusion after a mean postoperative follow-up of 13.8 years. No correlation between the number of degenerated discs or the degree of degeneration and subjective low back pain symptoms was found.     

腰椎间盘突出症髓核摘除术远期疗效分析

目的分析腰椎间盘突出症髓核摘除术后的远期疗效。方法对240例行髓核摘除术治疗的腰椎间盘突出症患者进行10年以上随访,分析患者术后症状缓解、恢复工作情况及对手术的满意程度,并对放射学资料保存完整的患者手术前后的腰椎间隙高度和稳定性进行对比。结果优良率:开窗组为85.4%,半椎板组为79.6%,全椎板组为47.2%。术后平均恢复工作时间:开窗组为4.2个月,半椎板组为4.5个月,全椎板组为4.7个月。所有病例虽术后椎间隙高度均有不同程度的丢失,但绝大多数患者术后未出现局部不稳。结论开窗法和半椎板切除髓核摘除术治疗腰椎间盘突出症可获得良好的远期疗效。髓核摘除术后椎间隙高度下降不一定导致椎间不稳和神经根受压。     

Disc degeneration and lumbar instability: Magnetic resonance examination of 16 patients

Flexion and extension radiographs of 75 young males with low back pain disclosed abnormal segmental motion of the lumbar spine in 16 patients with translational movements in 20 intervertebral segments. These 16 patients were further investigated by magnetic resonance imaging to assess disc degeneration in the unstable segments. On T2-weighted images of the 20 segments, the disc was normal in 13 and degenerated in only 7 patients. Thus, the initial factor in lumbar instability in young patients with low back pain is not always degeneration of the disc.     

棘突间动态内固定装置治疗腰痛的临床应用评价

目的 评价采用Coflex棘突间动态内固定植入术治疗腰痛的临床疗效及相关影像学改变.方法 2007年2月至2009年6月,对45例患者行Coflex棘突间内固定植入术,男26例,女19例;年龄45～70岁,平均51.4岁.治疗节段:L4.5 32例,L5S111例,L4.5、L5S1双节段2例.手术采用椎板开窗或部分切除,椎管减压后棘突间植入Coflex装置.按照Oswestry功能障碍指数(Oswestry disabi1ity index,ODI)和日本矫形外科学会(Japanese Orthopaedic Association,JOA)评分评价术前及术后随访时的临床疗效,计算恢复率.同时行影像学观察,包括椎间隙高度和椎间孔形态,手术节段椎体活动度和腰椎生理曲度,手术及相邻节段的MRI信号改变.结果 术后随访时间1O-34个月,平均24个月.ODI由术前62.82±10.42降至末次随访时11.80±3.35;JOA评分由9.00±2.63提高至24.65±1.86;最终疗效评价为显效的患者共40例,显效率为89%.L4.5、L5S1节段术后Cobb角分别为15.1°±3.9°和16.3°±3.8°,均较术前减小,生理曲度改善.L4.5节段椎体活动度(range of motion,ROM)由术前6.5°±1.5°增加至术后8.4°±2.6°,而L5S1节段ROM手术前后没有明显改变.无论是L4.5或是L5S1节段,末次随访时其椎间隙背侧高度、棘突顶距、椎间孔高度和椎间孔面积均较术前显著增加.结论 Coflex棘突间动态内固定中期随访临床疗效显著,并且保留了腰椎生理曲度和节段运动,增加并维持椎间隙高度和椎间孔面积,在手术节段椎间盘修复及防止相邻节段椎间盘退变等方面作用显著.     

Disc degeneration and lumbar instability. Magnetic resonance examination of 16 patients

Flexion and extension radiographs of 75 young males with low back pain disclosed abnormal segmental motion of the lumbar spine in 16 patients with translational movements in 20 intervertebral segments. These 16 patients were further investigated by magnetic resonance imaging to assess disc degeneration in the unstable segments. On T2-weighted images of the 20 segments, the disc was normal in 13 and degenerated in only 7 patients. Thus, the initial factor in lumbar instability in young patients with low back pain is not always degeneration of the disc.     

腰椎不稳定与腰椎间盘退变程度的相关性分析

目的：探讨腰椎不稳定与腰椎间盘退变程度的相关性。方法：随机选择100例腰腿痛病人,根据第一病人的腰椎功能位X线片和腰椎MRI图片,确定椎间盘的退变程度及有无节段不稳,并分析二者间关系。结果：L3－S1共有36个节段不稳,占12％;腰椎不稳29例,占病人总数的29％,L4／5、L3／4、L5／S1的不稳定发生率分别为22％、10％和4％;腰椎不稳与病人年龄分组呈现密切正相关,腰椎不稳与单节段退变及总退变度密切正相关,结论：腰椎不稳与椎间盘退变和蔼密切相关,但并非严重退变一定会发生节段不稳。     

What are the reliable radiological indicators of lumbar segmental instability?

We examined the reliability of radiological findings in predicting segmental instability in 112 patients (56 men, 56 women) with a mean age of 66.5 years (27 to 84) who had degenerative disease of the lumbar spine. They underwent intra-operative biomechanical evaluation using a new measurement system. Biomechanical instability was defined as a segment with a neutral zone > 2 mm/N. Risk factor analysis to predict instability was performed on radiographs (range of segmental movement, disc height), MRI (Thompson grade, Modic type), and on the axial CT appearance of the facet (type, opening, vacuum and the presence of osteophytes, subchondral erosion, cysts and sclerosis) using multivariate logistic regression analysis with a forward stepwise procedure. The facet type was classified as sagittally orientated, coronally orientated, anisotropic or wrapped. Stepwise multivariate regression analysis revealed that facet opening was the strongest predictor for instability (odds ratio 5.022, p = 0.009) followed by spondylolisthesis, MRI grade and subchondral sclerosis. Forward stepwise multivariate logistic regression indicated that spondylolisthesis, MRI grade, facet opening and subchondral sclerosis of the facet were risk factors. Symptoms evaluated by the Short-Form 36 and visual analogue scale showed that patients with an unstable segment were in significantly more pain than those without. Furthermore, the surgical procedures determined using the intra-operative measurement system were effective, suggesting that segmental instability influences the symptoms of lumbar degenerative disease.     

The change of whole lumbar segmental motion according to the mobility of degenerated disc in the lower lumbar spine: a kinetic MRI study

Purpose

To analyze the effects of mobility of degenerated disc in the lower lumbar discs (L4–5 and L5–S1) on both whole lumbar motion and adjacent segment ROM.

Methods

The kMRIs with disc degeneration at L4–5 or L5–S1 were classified into three groups: the normal group, the motion-preserved (MP) group and the motion-lost (ML) group based on range of motion (ROM) of 5° in the degenerated segment. Each segmental ROM, whole lumbar motion, and the contribution % of the upper lumbar spine (ULS: L1–2–3) and the lower lumbar spine (LLS: L4–5–S1) motion to whole lumbar motion were measured and compared with each of the other groups.

Results

There were 94, 99 and 66 patients in the normal group, MP group and ML group, respectively. The normal group showed no significant difference compared to the MP group in all ROM parameters. The ML group showed significantly less whole lumbar motion, more contribution % in the ULS and less in the LLS than the normal and the MP groups. The ROM in the superior adjacent segment in the ML group was not significantly different between that in the normal and MP group.

Conclusions

Degenerated lumbar discs did not show hypermobility within functional ROM. Loss of segmental ROM from advanced disc degeneration did not cause an increase in the ROM of the superior adjacent segment in vivo. When the LLS had motion-lost, advanced disc degeneration, whole lumbar motion was significantly decreased and compensatory increase in ROM was accomplished by the ULS.