Biomechanical analysis of the disc adjacent to posterolateral fusion with laminectomy in lumbar spine

OBJECTIVES: After posterolateral fusion with laminectomy for the degenerative lumbar spine, accelerated degeneration of the disc adjacent to the fusion mass has been clinically observed. Previous studies used a finite element model (FEM) to calculate the stress of the adjacent disc in the fused lumbar spine with spinal fixator and bone graft. However, little emphasis was placed on the simultaneous spinal fusion and decompression procedure. To investigate if the spinal decompression procedure in posterolateral fusion would increase stress significantly, the FEM was employed to estimate the stress concentration of the disc above the fusion mass in posterolateral fusion with laminectomy and hemilaminectomy. METHODS: Three FEMs of the lumbar spine were established: intact spine, posterolateral fusion with total laminectomy, and posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments). The posterolateral fusion added spinal fixator and bone graft between the transverse process. The L1 vertebral body was subjected to 10-Nm flexion, extension, torsion, and lateral bending. The bottom of the L5 vertebral body was fixed. RESULTS: In flexion, the stress on the adjacent disc in posterolateral fusion with laminectomy and hemilaminectomy respectively increased 90% and 21% over that of the intact spine. In posterolateral fusion with hemilaminectomy, the supraspinous and interspinous ligaments shared some external forces to alleviate the stress concentration of the adjacent disc. However, in extension, torsion, and lateral bending, these two fusion models had almost no change in range of motion and stress of adjacent disc. CONCLUSION: Posterolateral fusion with hemilaminectomy (preserved partial lamina, spinous process, and supraspinous and interspinous ligaments) was able to alleviate the stress concentration of the disc above the fusion mass in flexion.     

New aspects of lumbardisc disease

Summary Magnetic resonance imaging (MRI) and plain X-ray and CT studies were performed in patients with a history of lumbar back pain due to spinal disc disease. Spin-echo pulse sequences (SE), phase-contrast techniques (partial saturation sequences with delayed read-out, PS), and fat-suppressing inversion recovery sequences (STIR) were employed. In 74 of 325 patients, PS and STIR images displayed vertebral marrow changes adjacent to the end-plates of the affected segments. Bacterial infection, however, could be excluded. In six patients histological diagnosis showed substitution of hematopoietic marrow by fatty tissue, cartilaginous particles, degeneration of fat cells, and an increase in extracellular fluid with different components. The etiology is still unclear, but a correlation with lumbar disc disease is demonstrated. These vertebral marrow changes were best displayed with STIR and phase-contrast MR sequences, both providing contrast changes superior to T2-weighted     

间盘造影在近融合椎正常间盘的诊断价值

目的 采取回顾分析的研究方法，探讨椎间盘造影术在腰椎融合邻近正常椎间盘的诊断应用价值。方法 57例因椎间盘源性下腰痛行椎间盘切除和后路椎间融合术的患者。手术前行椎间盘造影时，不包括邻近融合节段的正常椎间盘。所有患者随访35．6个月（24-80个月）。对所有患者的临床疗效和影像学结果进行评价分析。结果 53例患者中49例临床效果优良，随访2年以上，38例患者无任何症状。15例患者在度过21个月的无症状期后出现疼痛复发，采用腰椎MRI和椎间盘造影复查。结果 MRI发现15例患者中的8例出现了邻近节段椎间盘的退变，而此8例中仅有1例（2％）经过MRI和椎间盘造影同时证实该节段为疼痛的原因，从而再次进行融合手术。结论 术前MRI上专现为正常的相邻椎间盘在椎间融合术后不容易变成病变节段，因此没有必要常规在术前为了排除病变节段，而行相邻于拟融合节段的正常椎间盘的造影检查。     

Retrolisthesis and lumbar disc herniation: a preoperative assessment of patient function.

BACKGROUND CONTEXT: Retrolisthesis is relatively rare but when present has been associated with increased back pain and impaired back function. Neither the prevalence of this condition in individuals with lumbar disc herniations nor its possible relation to preoperative back pain and dysfunction has been well studied. PURPOSE: The purposes of this study were as follows: (1) to determine the prevalence of retrolisthesis (alone or in combination with other degenerative conditions) in individuals with confirmed L5-S1 disc herniation who later underwent lumbar discectomy; (2) to determine if there is any association between retrolisthesis and degenerative changes within the same vertebral motion segment; and (3) to determine the relation between retrolisthesis (alone or in combination with other degenerative conditions) and preoperative low back pain, physical function, and quality of life. STUDY DESIGN/SETTING: Cross-sectional study. PATIENT SAMPLE: A total of 125 individuals were identified for incorporation into this study. All patients had confirmed L5-S1 disc herniation on magnetic resonance imaging (MRI) and later underwent L5-S1 discectomy. All patients were enrolled in the Spine Patient Outcomes Research Trial (SPORT) study; data were obtained from the multi-institutional database comprised of SPORT patients from across the United States. OUTCOME MEASURES: Retrolisthesis, degenerative change on MRI, and Modic changes. METHODS: MRI scans of the lumbar spine were assessed at spinal level L5-S1 for all 125 patients. Retrolisthesis was defined as posterior subluxation of 8% or more. Disc degeneration was defined as any loss of disc signal on T2 imaging. Modic changes were graded 1 to 3 and collectively classified as vertebral endplate degenerative changes. The presence of facet arthropathy and ligamentum flavum hypertrophy was classified jointly as posterior degenerative changes. RESULTS: The overall incidence of retrolisthesis at L5-S1 in our study was 23.2%. Retrolisthesis combined with posterior degenerative changes, degenerative disc disease, or vertebral endplate changes had incidences of 4.8%, 16%, and 4.8% respectively. The prevalence of retrolisthesis did not vary by sex, age, race, smoking status, or education level when compared with individuals with normal sagittal alignment. However, individuals with retrolisthesis were more likely to be receiving workers' compensation than those without retrolisthesis. Increased age was found to be associated with individuals having vertebral endplate degenerative changes (both alone and in conjunction with retrolisthesis) and degenerative disc disease. Individuals who had retrolisthesis with concomitant vertebral endplate degenerative changes were more often smokers and had no insurance. The presence of retrolisthesis was not associated with an increased incidence of having degenerative disc disease, posterior degenerative changes, or vertebral endplate changes. No statistical significance was found between the presence of retrolisthesis on the degree of patient preoperative low back pain and physical function. Patients with degenerative disc disease were found to have increased leg pain compared with those patients without degenerative disc changes. CONCLUSIONS: We found no significant relationship between retrolisthesis in patients with L5-S1 disc herniation and worse baseline pain or function. It is possible that the contribution of pain or dysfunction related to retrolisthesis was far overshadowed by the presence of symptoms caused by the concomitant disc herniation. It remains to be seen whether retrolisthesis will affect outcome after discectomy in these patients.     

腰椎间盘退变性疾患下腰椎终板形态的MRI观察

【摘要】　目的：在MRI片上观察腰椎间盘退变患者下腰椎终板形态的分布规律,分析终板形态和椎间盘退变的关系。方法：回顾分析两组腰椎间盘退变性疾病患者的术前腰椎MRI,A组110例为单节段腰椎间盘突出症患者,B组35例为椎间盘源性腰痛患者。根据正中矢状面MRI T1像,将终板形态分为凹面、平坦、不规则三型;根据Pfirrmann法评定椎间盘退变程度并将Ⅰ～Ⅴ级分别计为1～5分;按Modic改变分级标准判定各节段终板有无Modic改变。分析下腰椎终板的形态特点及三种分型与椎间盘退变程度、Modic改变等的关系。结果：①435个下腰椎节段中,凹面型终板最多（215/435）,A组中占50.6％（167/330）,B组中占45.7％（48/105）,且主要分布于L3/4（108/215）、L4/5（83/215）节段;平坦型终板占29.0％（126/435）,并主要位于L5/S1节段（76/126）;不规则型终板最少（94/435）,A组中占23.0％（76/330）,B组中占17.1％（18/105）,也主要位于L5/S1节段（45/94）。②A组患者中,凹面型终板退变程度平均为3.31±0.81分,平坦型为3.66±0.64分,不规则型为4.16±0.67分,两两比较有显著差异（P＜0.05）;椎间盘突出节段以平坦型（37/110）和不规则型（43/110）终板占多数,无突出节段则以凹面型（137/220）终板占多数,差异有显著性（P＜0.05）;不规则型终板比凹面型和平坦型更容易伴发Modic改变,差异有显著性（P＜0.05）,凹面型和平坦型间无显著性差异（P＞0.05）。③B组患者中,凹面型终板的椎间盘退变程度平均为3.23±0.86分,平坦型为3.54±0.85分,不规则型为3.94±0.54分,仅凹面型和不规则型间差异有显著性（P＜0.05）。④相同终板形态时A组和B组椎间盘退变程度相比均无显著性差异（P＞0.05）。结论：终板形态与椎间盘退变、Modic改变之间有相关性。终板形态由凹面型到平坦型再到不规则型,腰椎间盘退变程度逐渐加重。影像学上终板形态改变在一定程度上反映了椎间盘退变的程度。     

Correlation between sagittal plane changes and adjacent segment degeneration following lumbar spine fusion

Adjacent segment degeneration following lumbar spine fusion remains a widely acknowledged problem, but there is insufficient knowledge regarding the factors that contribute to its occurrence. The aim of this study is to analyse the relationship between abnormal sagittal plane configuration of the lumbar spine and the development of adjacent segment degeneration. Eighty-three consecutive patients who underwent lumbar fusion for degenerative disc disease were reviewed retrospectively. Patients with spondylolytic spondylolisthesis and degenerative scoliosis were not included in this study. Mean follow-up period was 5 years. Results were analysed to determine the association between abnormal sagittal configuration and post operative adjacent segment degeneration. Thirty-one out of 83 patients (36.1%) showed radiographic evidence of adjacent segment degeneration. Patients with normal C7 plumb line and normal sacral inclination in the immediate post operative radiographs had the lowest incidence of adjacent level change compared with patients who had abnormality in one or both of these parameters. The difference was statistically significant (P<0.02). There was no statistically significant difference in the incidence of adjacent level degeneration between male and female patients; between posterior fusion alone and combined posterolateral and posterior interbody fusions; and between fusions extending down to the sacrum and fusions stopping short of the sacrum. It was concluded was that normality of sacral inclination is an important parameter for minimizing the incidence of adjacent level degeneration. Retrolisthesis was the most common type of adjacent segment change. Patients with post operative sagittal plane abnormalities should preferably be followed-up for at least 5 years to detect adjacent level changes.     

有限减压相邻节段植骨内固定术治疗胸腰椎骨折

[目的]研究有限减压相邻节段椎弓根内固定椎间、椎内植骨融合术治疗胸腰椎骨折的可行性和临床疗效。[方法]回顾性研究应用该技术治疗的43例胸腰椎骨折患者,观察植骨融合及复位情况、神经功能恢复情况,及矫正丢失、腰痛后遗症和融合椎体相邻椎间盘退变等并发症发生情况。[结果]平均随访21.4个月,所有患者均达到坚强骨性融合,均得到满意的复位,复位率达96.1%,近期内无明显矫正丢失,术后神经功能均得到不同程度的恢复,术前术后秩和检验P<0.01,且融合节段相邻椎间盘退变率仅为4.65%,未出现顽固性腰痛、腰椎活动受限等并发症,临床疗效明显优于长节段内固定。[结论]只要适应证选择合适,有限减压相邻节段内固定椎间、椎内植骨融合内固定术不但可以达到满意复位、坚强骨性融合,而且可以明显降低顽固性腰痛、相邻椎间盘退变等并发症的发生率。     

基于腰椎间盘退变的脊柱稳定性改变的MRI研究进展

腰椎间盘是位于两个相邻椎体之间的圆盘状纤维软骨,是维持脊柱稳定性的重要解剖结构。目前,维持脊柱稳定性的解剖结构分为被动亚系、主动亚系和神经控制亚系,称为"三亚系模型",腰椎间盘退变(intervertebral disc degeneration,IVDD)会引起该模型其它组织的病理学改变,且彼此相互作用导致脊柱稳定性下降,是下腰痛最常见的原因。IVDD患者常伴有椎小关节及韧带的退变、邻近椎体Modic改变、椎体血流量减少、椎旁肌肉脂肪浸润增加、神经轴向牵拉损伤的代偿性减少等。磁共振成像(magnetic resonance imaging,MRI)是评估脊柱稳定性首选的影像学方法,常规MRI能完整显示IVDD患者三亚系模型相关组织形态学变化,MRI功能成像能定量分析其病理生理学变化的程度。本文综述IVDD患者腰椎间盘、椎小关节、韧带、椎体、肌肉、神经的MRI形态学及定量值变化,阐述IVDD引起脊柱稳定性改变的相关机制,旨在为下腰痛患者的精准诊疗提供更全面的信息。     

人工椎间盘在腰椎退行性疾病中的临床应用进展

腰椎间盘退行性疾病是脊柱外科常见疾病,也是成年人腰痛和伤残的主要原因之一。传统观念认为腰椎融合术的临床效果是肯定的,但没有保留脊柱的生理运动功能,并且腰椎运动节段的融合加快了邻近节段椎间盘及小关节的退变。腰椎功能解剖学和生物力学领域深入的研究使得不同构造和材质的现代人工椎间盘装置的发展成为可能。人工腰椎间盘置换术作为腰椎融合之外治疗腰椎退行性疾病的另一合理的选择,目的是使退变椎间盘引起的疼痛得到长期缓解,重建椎间隙高度以保护神经组织,保留脊柱运动以避免晚期关节突关节及邻近节段的病变,恢复脊柱的运动学和载荷特性。本综述旨在阐释人工腰椎间盘的类型,该领域中的研究及临床应用进展和发展前景。     

Vertebral end-plate (Modic) changes on lumbar spine MRI: correlation with pain reproduction at lumbar discography

The vertebral end-plate has been identified as a possible source of discogenic low back pain. MRI demonstrates end-plate (Modic) changes in 20–50% of patients with low back pain. The aim of this study was to investigate the association between Modic changes on MRI and discogenic back pain on lumbar discography. The MRI studies and discograms of 58 patients with a clinical diagnosis of discogenic back pain were reviewed and the presence of a Modic change was correlated with pain reproduction at 152 disc levels. Twenty-three discs with adjacent Modic changes were injected, 21 of which were associated with pain reproduction. However, pain was also reproduced at 69 levels where no Modic change was seen. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for a Modic change as a marker of a painful disc were 23.3%, 96.8%, 91.3% and 46.5% respectively. Modic changes, therefore, appear to be a relatively specific but insensitive sign of a painful lumbar disc in patients with discogenic low back pain. Received: 24 October 1997 Revised: 11 March 1998 Accepted: 21 April 1998     

42例腰椎融合术后难治性下腰痛的治疗体会

目的探讨腰椎融合术后骶髂关节病变的特点及治疗方法与疗效。方法回顾性分析42例因腰椎退变性滑脱、腰椎椎间盘突出、腰椎椎管狭窄曾行后路减压、后外侧或椎体间植骨融合及椎弓根内固定术,术后随访12～72个月(平均42.6个月)出现新的难治性持续性下腰痛症状的病例。本研究运用骶髂关节内封闭进行诊断性治疗。阳性标准:疼痛缓解≥75%,采用疼痛视觉模拟量表(visual analogue scale,VAS)进行定量分析。结果阳性12例(28.57%),是否融合L5/S1、术后疼痛缓解期是否≥3个月与诊断阳性率相关,有统计学意义(P<0.05)。结论腰椎融合术后下腰痛部分可能是由骶髂关节病变引起的,L5/S1融合可能促进骶髂关节发生退变。症状以下腰痛症状为主者,手术应慎重。     

下腰椎内固定融合手术后复发性腰痛及下肢放射痛23例原因分析

目的分析椎弓根螺钉内固定下腰椎融合手术后腰痛原因。方法随访2001年1月~2003年12月采用椎弓根螺钉内固定下腰椎融合手术103例,男43例,女60例;腰椎滑脱28例,腰椎管狭窄54例,腰椎间盘突出症21例。随访时进行问卷调查及X线、CT或MRI检查,并分析手术后腰痛的可能原因。结果随访时间3~5年,疗效优良80例(77.7%);术后有明显腰痛或腰痛伴下肢放射痛23例(22.3%)。邻近节段疾病11例(2节段融合7例,1节段融合4例;10.7%),内固定使用不当3例,椎弓根螺钉断裂2例,减压不完全2例,高位椎间盘突出1例,不明原因4例。结论邻近节段疾病、内固定使用不当、内固定失败是复发性腰痛主要原因。原有退变基础、减压范围超过融合节段、融合节段的长短都是产生邻近节段疾病的重要的危险因素。     

A novel lumbar total joint replacement may be an improvement over fusion for degenerative lumbar conditions: a comparative analysis of patient-reported outcomes at one year

Background contextEffective alternatives to lumbar fusion for degenerative conditions have remained elusive. Anterior total disc replacement does not address facet pathology or central/recess stenosis, resulting in limited indications. A posterior-based motion-preserving option that allows for neural decompression, facetectomy, and reconstruction of the disc and facets may have a role.PurposeThe purpose was to compare one-year patient-reported outcomes for a novel, all-posterior, lumbar total joint replacement (LTJR – replacing both the disc and facet joints) against transforaminal lumbar interbody fusion (TLIF) for degenerative lumbar conditions warranting fusion (degenerative spondylolisthesis, recurrent disc herniation, severe foraminal stenosis requiring facet removal, and adjacent segment degeneration).Study design/settingA retrospective analysis of prospectively collected data comparing outcomes for LTJR patients to TLIF patients at an academic teaching hospital.Patient sampleAnalysis was conducted on 156 adult TLIF patients who were propensity matched to the 52 LTJR patients for a total sample of 208.Outcome measuresSelf-reported Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) for back and leg pain were compared preoperatively, 3 months and 1 year after surgery.MethodsThe implant is a motion-preserving lumbar reconstruction that replaces the function of both the disc and facets and is implanted using a bilateral transforaminal approach with complete facetectomies. Adult patients with degenerative lumbar pathology undergoing either LTJR or open TLIF were analyzed. These degenerative conditions included: grade 1 degenerative spondylolisthesis, recurrent disc herniation, adjacent segment disease, disc degeneration with severe foraminal stenosis). Trauma, tumor, grade 2 or higher spondylolisthesis, spinal deformity, and infection cases were excluded. Propensity score matching was performed to ensure parity between the cohorts. Multivariable regression analyses were done to compare the 1-year results as measured by 3 different standards to assess procedure success.ResultsAt 3 months, both the LTJR and TLIF cohorts showed significant and similar improvements in ODI and NRS back and leg pain. At 1 year, the LTJR cohort showed continued improvement in ODI and NRS back pain, while the TLIF group showed a plateau for ODI, back and leg pain. In a series of three multivariable logistic regressions, LTJR was shown to provide 3.3 times greater odds of achieving the minimal clinical symptom state in disability and pain (ODI <20%, NRS back and leg pain <2) and 2.4 and 4.1 times greater odds of achieving substantial clinical benefit (18% reduction in ODI) and minimal clinically important difference (30% reduction in ODI) as compared to TLIF.ConclusionsHere we present a comparative analysis for the first 52 patients undergoing a novel, posterior-based LTJR for the lumbar spine versus TLIF for degenerative pathology. The approach for the LTJR allows for wide neural decompression, facetectomy, and complete discectomy, with the implant working to replace the function of the disc and facets to preserve motion. At 1 year, the LTJR cohort showed significant improvement in ODI and NRS back and leg pain as compared to TLIF. These results suggest that wide neural decompression combined with motion preservation using this novel LTJR may represent a viable alternative to TLIF for treating certain degenerative conditions. A prospective controlled trial is under development to further evaluate the efficacy, safety, and durability of this procedure.     

腰椎间盘退变后椎体的变化及其临床意义

目的研究腰椎退变时椎体的形态和骨密度的变化规律,探讨其临床意义。方法选择对照组患者31例,腰椎退变组患者94例,通过应用计算机处理其X线片和MRI等影像学资料,测定L4,L5椎体的骨密度和测定腰椎椎体的周径和对角径、相对高度,相对矢状径及对角径等,同时观察MRI上椎体骨髓信号的改变。应用SPSS11.5对实验数据进行处理。结果①对照组L4及L5椎体指数在男女间比较差异无显著性(P>0.05)。提示X线侧位片上男、女L4及L5椎体的形态相似。②L4及L5椎体指数在对照组明显大于退变组,之间比较有显著性差异(P<0.05)。③L4及L5椎体相对高度在对照组均较退变组高,而椎体的上下矢状径对照组较退变组要小,对角距差别不大;比较具有统计学上的差异显著性(P<0.05)。④椎体骨密度测定结果显示两组间有显著差异性(P<0.05)。结论腰椎间盘退变后,椎体发生改变与否与椎间盘退变的程度成正相关。     

The effects of bone density and disc degeneration on the structural property distributions in the lower lumbar vertebral endplates.

In this study, we hypothesized that vertebral bone density and disc degeneration would affect the structural property distributions of the lower lumbar vertebral endplates (L3-L5). The results may have implications for improving interbody implant designs to better resist subsidence. A 3 mm diameter hemispherical indenter was used to perform indentation tests at 0.2 mm/s to a depth of 3 mm at 27 standardized locations in 55 bony endplates of intact human lumbar vertebrae (L3-L5). The resulting load-displacement curves were used to extract the failure load and stiffness of each test site. Bone density was measured using lateral DEXA scans. Disc condition was determined using a four-point grading scale. Three-way analyses of variance were used to analyze the relationships between the data. The overall failure load decreased with bone mineral density (BMD) in the superior (p < 0.0001) and inferior (p = 0.011) lumbar endplates. In both endplates, the posterolateral regions were significantly stronger than more central regions. With increasing BMD, this difference became more pronounced in the superior endplates only (p = 0.005). Increased disc degeneration was associated with an overall failure load decrease in the inferior lumbar endplates (p = 0.002). The strength in the central regions of the superior endplates was reduced with increasing degeneration, but this was not observed peripherally (p = 0.001). Stiffness magnitude or distribution was not significantly affected by BMD or disc degeneration. The locations of the strongest regions of the endplate did not change with either bone density or disc degeneration. This implies that implant shapes designed using the basic structural property maps for the L3-L5 endplates are appropriate for use in patients with a wide range of pathologies, even though overall failure loads are generally lower in patients with reduced bone density and greater degrees of disc degeneration.     

腰椎Active-L人工椎间盘置换术与腰椎融合术的临床比较研究

背景：腰椎融合术一直被广大学者认为是治疗腰椎间盘退行性病变的“金标准”,但文献报道腰椎融合术加速相邻节段退变的发生,为保留脊柱功能单位的生理和运动特性,提出人工椎间盘置换术。目的：比较前路Active．L型人工椎间盘假体置换术和后路腰椎融合术治疗单节段腰椎间盘退行性病变患者的疗效和安全性。方法：2009年1月至2010年4月62例因腰椎间盘退行性病变的手术患者,根据手术方式分为试验组和对照组。试验组行腰椎人工椎间盘置换术患者20例,男10例,女10例;年龄36-58岁,平均47．7岁;术前诊断：腰椎间盘突出症16例,腰椎间盘源性下腰痛4例,腰椎间盘后路开窗术后复发1例;手术节段：13-42例,L4-513例,L5-S15例。对照组行腰椎融合术患者42例,男22例,女20例;年龄40-60岁,平均48．5岁;术前诊断：腰椎间盘突出症32例,腰椎间盘源性下腰痛7例,腰椎间盘后路开窗术后复发3例;手术节段：13-44例,L4-526例,15-S112例。随访观察指标包括：（1）临床疗效评定：术后疼痛及功能改善率的评定;手术成功率的评定。（2）影像学评定：腰椎前凸角和手术节段的椎问活动度独立因素t检验进行对比评价。结果：全部获得随访,试验组随访时间为12-27个月,平均19．3个月;对照组随访时间为12-27个月,平均19．8个月。两组患者在治疗下腰痛方面均取得明显疗效。在改善ODI功能评分、VAS疼痛评分、SF-36、椎间隙活动度上,试验组优于对照组,两组间比较有显著性差异（P〈0．05）;在恢复腰椎前凸序列上,两组间无显著性差异（P〉0．05）;两组均未出现严重并发症。结论：人工椎间盘置换术和融合术均取得良好的临床效果,但人工椎间盘置换术在掌握严格的手术适应证和禁忌证的条件下,相比腰椎融合术具有更好的临床疗效并保留病变节段的活动度。因此,在合适的手术适应证下,人工间盘置换术是一种更优且可以替代腰椎融合术的有效治疗方法。     

Disc degeneration of cervical spine on MRI in patients with lumbar disc herniation: comparison study with asymptomatic volunteers

An association between progression of cervical disc degeneration and that of lumbar disc degeneration has been considered to exist. To date, however, this association has not yet been adequately studied. Age-related changes in the cervical intervertebral discs were evaluated by magnetic resonance imaging (MRI) in patients with lumbar disc herniation, and compared with the MRI findings of healthy volunteers without lower back pain. The purpose of this study was to clarify whether the prevalence of asymptomatic cervical disc degeneration is higher in patients with lumbar disc herniation than in healthy volunteers. The study was conducted on 51 patients who were diagnosed as having lumbar disc herniation and underwent cervical spine MRI. The patients consisted of 34 males and 17 females ranging in age from 21–83 years (mean 46.9 ± 14.5 years) at the time of the study. The control group was composed of 113 healthy volunteers (70 males and 43 females) aged 24–77 years (mean 48.9 ± 14.7 years), without neck pain or low back pain. The percentage of subjects with degenerative changes in the cervical discs was 98.0% in the lumbar disc herniation group and 88.5% in the control group (p = 0.034). The presence of lumbar disc herniation was associated significantly with decrease in signal intensity of intervertebral disc and posterior disc protrusion in the cervical spine. None of the MRI findings was significantly associated with the gender, smoking, sports activities, or BMI. As compared to healthy volunteers, patients with lumbar disc herniation showed a higher prevalence of decrease in signal intensity of intervertebral disc and posterior disc protrusion on MRI of the cervical spine. The result of this study suggests that disc degeneration appears to be a systemic phenomenon.     

Quantitative MRI analysis of the surface area, signal intensity and MRI index of the central bright area for the evaluation of early adjacent disc degeneration after lumbar fusion

Purpose

The aim of this study was to evaluate early ASD at short-term follow-up in fused and unoperated patients with degenerative disc disease, using quantitative magnetic resonance imaging (MRI) analysis of the area, signal intensity and their product, i.e., MRI index of the central bright area of the disc as well as measures of intervertebral disc height and Pfirrmann grading scale. The further purpose was to determine whether fusion accelerates ASD compared with non-surgical treatment in short-term follow-up.

Methods

One hundred and eight chronic low back patients diagnosed as L4/L5 degeneration undertook either one-level instrumented posterior lumbar interbody fusion or conservative treatment. They were followed up for about 1?year. Finally 46 fused and 45 conservatively treated patients with MRI follow-up were included. Pre- and post-treatment MRIs were compared to determine the progression of disc degeneration at the two cranial adjacent segments.

Results

The area, signal intensity and MRI index of the central bright area of the adjacent discs decreased in the operated and unoperated groups from pre-treatment to follow-up, except for an insignificant decrease of signal intensity at the second adjacent segment in the unoperated group. The changes in these parameters were statistically greater at the first than the second adjacent segment in the fused group, but not in the unoperated group. And the changes in the fused group were more pronounced than those at both neighbouring levels in the unoperated group. However, the Pfirrmann grading scale and intervertebral disc height did not detect any changes at adjacent discs in either group.

Conclusions

Decrease in the parameters of quantitative MRI analysis indicated early degeneration at discs adjacent to lumbar spinal fusion. Fusion had an independent effect on the natural history of ASD during short-term follow-up. Continued longitudinal follow-up is required to determine whether these MRI changes lead to pathologic changes.     

Surgical Results after Soft System Stabilization of the Lumbar Spine in Degenerative Disc Disease – Long Term Results

Summary  After having reported preliminary results of soft system stabilization according to Graf in a series of 27 patients with degenerative disc disease of the lumbar spine in early 1995 the authors report long term clinical and radiological results of this patient series (n=25). At a mean period of postoperative observation of 50 months excellent, good, satisfactory, moderate and poor results were obtained in 62,9%, 11,1% and 11,1%, 7,4% and 7,4 % of the patients, respectively. The well-known phenomenon of loss of disc height at the level of posterolateral fusion and instrumentation as well as overcharge of adjacent segments were not observed after soft system stabilization. Regional as well as global lumbar lordosis were maintained and, although statistically not significant, an increase of intervertebral distance was observed in adjacent segments in flexion of the lumbar spine. These phenomena might represent pressurization of instrumented as well as adjacent discs after the insertion of ligament prostheses. It is the impression of the authors, that the Graf technique leads to good surgical results in degenerative disc disease with destabilization of lumbar motion segment(s) if the following criteria are strictly respected: 1.*No or only mild arthrotic changes of the facet joints 2.*Preferably minor disc degeneration/only mild loss of intervertebral distance 3.*Well trained low back muscles and 4.*A clear-cut, repeatedly demonstrated pain-relief on trial anaesthesia of the corresponding articular nerves and while wearing a probatory jacket.     

Surgical treatment of symptomatic degenerative lumbar spondylolisthesis by decompression and instrumented fusion

Degenerative spondylolisthesis is characterized by the slippage of one vertebral body over the one below, with association of intervertebral disc degeneration and degenerative arthritis of the facet joints, which cause spinal stenosis. The aim of this study was to evaluate the clinical and radiographic results of 22 patients with symptomatic degenerative spondylolisthesis, operated on by decompressive laminectomy and instrumented posterolateral fusion associated with interbody fusion (PLIF). Mean age at surgery was 64 years (range, 57–72). Clinical results were evaluated on a questionnaire at the last follow-up visit concerning postoperative low back and leg pain, restriction of daily life activities, and resumption of sports activity. Lumbar spine radiographs were used to evaluate the status of fixation devices, the reduction of the spondylolisthesis, the lumbar sagittal balance and the presence of spinal fusion. No intraoperative or postoperative complications were encountered. There were no superficial or deep infections, fixation device loosening, or hardware removal. Mean follow-up time was 4 years (range, 3–6 years). Clinical outcome was excellent or good in 19 patients and fair in 3 patients. Preoperatively, mean forward vertebral slipping on neutral lateral radiographs was 5 mm, while postoperatively it decreased to 3 mm. Preoperatively, mean sagittal motion was 3 mm and angular motion was 8°, while postoperatively these values decreased to 1 mm and 1°, respectively. This study demonstrated that spinal decompression followed by transpedicular instrumentation associated with PLIF technique is a valid surgical option for the treatment of degenerative spondylolisthesis with symptomatic spinal stenosis. Clinical outcome, intended as relief of pain and resumption of activity, was improved significantly and fusion rate was high.