Magnetic resonance classification of lumbar intervertebral disc degeneration

Estudo comparativo dos mecanorreceptores dos discos intervertebrais normais e degenerados da coluna lombar de humanos pela radiografia, ressonância magnética e estudo anatomopatológico

Os autores fizeram um estudo da coluna lombar de humanos, objetivando avaliar e determinar os diferentes tipos de fibras nervosas no disco intervertebral normal e no degenerado. Foram usadas dez colunas lombares de cadáveres com aproximadamente 48 a 72 horas de óbito. As peças foram submetidas a exames de radiografia simples e ressonância magnética. Após os exames, os discos foram classificados em normais e degenerados. Em seguida, foram dissecados, divididos em regiões anterior e posterior, incluídos em parafina e realizado estudo de imuno-histoquímica com a proteína S100. Com o auxílio de um programa de computador Image-Pro Plus (media cybernetics®), as fibras nervosas tiveram seu diâmetro medidos em micrômetros e classificadas em quatro tipos de fibras. Foram encontrados quatro tipos de fibras nervosas nas diferentes regiões discais. O número e o tipo de fibras variaram de acordo com a região e grau de degeneração do disco intervertebral. Concluíram que as fibras do tipo III são mais freqüentes na região anterior; as fibras dos tipos II e IV são mais freqüentes na região posterior, e as fibras do tipo I não apresentaram diferenças entre a região anterior e a posterior; além disso, o disco degenerado tem mais fibras nervosas que o disco normal.

Correlation of end plate shape on MRI and disc degeneration in surgically treated patients with degenerative disc disease and herniated nucleus pulposus

BACKGROUND CONTEXT

The sagittal profile of the lumbar end plates on magnetic resonance imaging (MRI) has not been investigated in patients with degenerative disc disease (DDD) or herniated nucleus pulposus (HNP).

PURPOSE

To examine the shape of the end plates in patients treated surgically for a) low back pain or b) radiculopathy with HNP. Furthermore, to investigate the correlation between end plate shape and disc degeneration on the one, and end plate shape and symptoms on the other.

STUDY DESIGN/SETTING

Retrospective review of charts and radiographs.

METHODS

The charts, operative reports, preoperative lateral plain radiographs, and MRI scans of 178 patients (85 with low back pain and 93 with HNP) were reviewed. End plate shape was determined on midsagittal MRI cuts, disc degeneration was graded on T2 sequences, and disc height was measured on lateral plain radiographs from L1 to S1 in all patients. Student t-test and chi(2) test were used to detect significant differences and associations.

RESULTS

Flat and irregular levels were most common in the lower lumbar spine. The L5/S1 segment was flat in most cases, due to a flat sacral end plate. In DDD patients, disc degeneration on MRI and plain radiographs worsened from concave to flat, to irregular levels. In HNP patients, MRI demonstrated concave levels to be less degenerated, whereas no difference was detected between flat and irregular levels. Disc height of irregular levels was well preserved in HNP patients. Comparing the two groups, flat levels were more degenerated on MRI in HNP patients. Despite similar degrees of degeneration on MRI, concave and irregular levels in DDD patients had lower disc heights. A higher frequency of symptoms was found in flat and irregular levels for both patient groups.

CONCLUSIONS

The sagittal profile of end plates in the lumbar spine was described for patients with DDD on the one and HNP on the other. A higher association with symptoms was observed for flat and irregular levels in both patient groups. In DDD patients, disck degeneration on both MRI and plain radiographs increased from concave to flat, to irregular levels. In HNP patients, MRI demonstrated concave levels to be less degenerated, whereas no difference was detected between flat and irregular levels. Disc height of irregular levels was well preserved in HNP patients. Comparing the two groups of patients, flat levels were more degenerated on MRI in HNP patients. Despite similar degrees of degeneration on MRI, concave and irregular levels in DDD patients had lower disc heights. The correlation of symptoms and disc degeneration with the end plate shapes is not definitive evidence of end plate remodeling around degenerated discs. It may simply represent the higher rate of disc degeneration in the lower lumbar levels. This analysis did not provide any hints as to which degenerated discs are more likely to herniated and cause leg symptoms or cause predominantly low back pain.

The treatment of disc-herniation-induced sciatica with infliximab: one-year follow-up results of FIRST II, a randomized controlled trial

STUDY DESIGN

A randomized controlled trial.

OBJECTIVES

To evaluate the long-term efficacy of infliximab, a monoclonal antibody against tumor necrosis factor alpha (TNF-alpha), in patients with acute/subacute sciatica secondary to herniated disc.

SUMMARY OF BACKGROUND DATA

The results of experimental studies and our open-label trial support the use of infliximab in sciatica. Here we report the 1-year results of a randomized controlled trial (FIRST II, Finnish Infliximab Related STudy) evaluating the efficacy and safety of a single infusion of infliximab for sciatic pain.

METHODS

Inclusion criteria were unilateral sciatic pain with a disc herniation concordant with the symptoms and signs of radicular pain. Patients had to be candidates for discectomy. Criteria for discectomy included (in addition to a symptomatic disc herniation on MRI) neural entrapment (straight leg raising [SLR] < or =60 degrees ) with either a short-term (2-4 weeks) severe or long-term (4-12 weeks) moderate leg pain. Forty patients were allocated to a single intravenous infusion of either infliximab 5 mg/kg or placebo. Differences in the clinical examination parameters (straight leg raise [SLR], muscle strength, sensory defects, tendon reflexes), patient-reported symptoms (leg and back pain using a visual analog scale [VAS], Oswestry disability, quality-of-life [RAND-36]), sick leaves, number of discectomies, and adverse effects between the two treatment groups over the 1-year follow-up were compared using Mann-Whitney U test or Student's t test, repeated-measures analysis, or Cox proportional hazards model. Logistic regression was used to assess the predictors of good response.

RESULTS

Sixty-seven percent of patients in the infliximab group reported no pain at 52 weeks compared with 63% in the control group (P = 0.72). Similar efficacy was observed between treatment groups for other outcomes. Eight patients in each group required surgery. Three nonserious adverse reactions were encountered in the infliximab group. The response (irrespective of the treatment) was significantly better with shorter symptom duration and less SLR restriction at baseline. Patients in the infliximab group appeared to especially benefit in cases of a L4-L5 (or L3-L4) herniation and if a Modic change was colocalized at the symptomatic level.

CONCLUSIONS

Although the long-term results of this randomized trial do not support the use of infliximab compared with placebo for lumbar radicular pain in patients with disc herniation-induced sciatica, further study in a subgroup of patients with L4-L5 or L3-L4 herniations, especially in the presence of Modic changes, appears to be warranted.

Magnetic resonance imaging of the lumbar spine: findings in female subjects from administrative and nursing professions

STUDY DESIGN

Cross-sectional magnetic resonance imaging (MRI) study.

OBJECTIVE

To find out whether different patterns of lumbar disc degeneration related to different physical work types (static vs. dynamic) can be found.

SUMMARY OF BACKGROUND DATA

The association of lumbar disc degeneration with physical workload as well as the association of disc degeneration with low back pain (LBP) has been debated controversially. Nevertheless, many of the mainly invasive treatment concepts are based on disc degeneration models.

METHODS

An MRI study was performed in female subjects aged 45 to 62 years with persistent LBP and in age-matched controls. Subjects (n = 109) were selected from nursing and administrative professions. A questionnaire was used to assess the subjects' exposure to physical workplace factors. Disc degeneration, disc herniation, nerve root compromise, high intensity zones, endplate changes, and facet joint osteoarthritis were evaluated based on sagittal T1- and T2-weighted as well as axial T2-weighted images.

RESULTS

The two occupational groups could clearly be distinguished by the physical workplace factors: administrative work was associated with predominantly sitting postures whereas nursing work was associated with frequent walking, pushing, pulling, and lifting. Except for endplate (Modic) changes at L5-S1, MRI findings did not differ between the four groups, namely, nurses and secretaries with and without LBP. When analyzing the MRI findings within the two vocational groups, nerve root compromise and endplate changes in the lower lumbar spine were found to be significant (P < 0.05) risk factors for LBP. Disc degeneration, disc herniation, nerve root compromise, and facet joint osteoarthritis were present in more than 50% of the intervertebral spaces studied.

CONCLUSIONS

These findings give evidence that in subjects performing nonheavy work, patterns of lumbar disc degeneration are not associated with the job type and characteristic physical loadings.

Magnetic resonance imaging and spectroscopy of the intervertebral disc

Intervertebral disc disease is an emerging health concern and has a considerable negative effect on the economy and on society. MRI has a critical role in assessing the disc, but it is still a challenge to objectively correlate disc health and pain with images. In this paper, a review of MR disc imaging techniques including grading, relaxation time measurements, diffusion, and contrast perfusion is presented. In addition, high-resolution magic-angle spinning methods to correlate in vitro disc degeneration (with pain, etc) are discussed. With the potential for gaining morphological and biochemical information, MRI shows promise for quantitative assessment of disc health.

Measuring CSF Flow in Chiari I Malformations

Cardiac-gated Phase Contrast MR (PC MR) is used in the evaluation of the Chiari I malformation to assess the CSF flow though the foramen magnum. Images may show reduced CSF flow posterior to the spinal cord in patients with a Chiari I malformation. MR images however do not differentiate with sufficient accuracy between symptomatic and asymptomatic Chiari I malformations. In the presence of the Chiari I malformation, CSF velocities are elevated. Measuring the velocity of flow and determining the degree of inhomogeneity in CSF flow aid in the detection of clinically significant flow abnormalities.

Dynamic MR and Quantitative MR Applied to the Study of Intervertebral Disk Degeneration

MR and CT demonstrate morphological changes in intervertebral disks. However the images do not provide an effective means to document interval changes in the disk due to degeneration, aging or healing. Functional imaging that may assesses the biomechanical or the biochemical integrity of the disk, may provide a measure of changes in the disk over time. To study the biomechanical function of the disk, translation and rotation of spinal vertebrae can be measured with CT or MR as the spine is subjected to a specific load or torque. Biochemical integrity of the disk can be assessed by the estimation of the water content from a measurement of the T2 relaxation time of disk tissue.

In vivo quantification of delayed gadolinium enhancement in the nucleus pulposus of human intervertebral disc

PURPOSE

To quantify the delayed contrast agent enhancement in the nucleus pulposus of the intervertebral disc by means by T1 relaxation time measurements, and to correlate the enhancement with visual grading of disc degeneration. Diffusion of nutrients through the endplate is a key factor in tissue viability in the intervertebral disc. It can be simulated in vivo using magnetic resonance imaging (MRI) by measuring delayed gadolinium (Gd) enhancement of the disc.

MATERIALS AND METHODS

Twenty male volunteers underwent a lumbar spine examination at 1.5T. T2-weighted sagittal images were used to score disc degeneration. T1 relaxation times were measured before and 90 minutes after intravenous administration of Gd-DTPA-BMA by applying a series of sagittal single-slice inversion-recovery fast spin-echo (IR-FSE) scans.

RESULTS

A total of 93 discs were analyzed. A statistically significant decrease in the T1 relaxation time of the nucleus pulposus was observed as a result of contrast-agent intake. The percentage change in the T1 relaxation rate for individual discs was up to 126%. A positive trend was observed between the change in the T1 relaxation rate and the grading of disc degeneration.

CONCLUSION

Quantification of delayed enhancement of the intervertebral disc may provide a new means of studying alterations in degenerative disc disease (DDD) that explain the variation in diffusion into the intervertebral disc.

Diagnostic relevance of pressure-controlled discography

Discogenic pain is a leading cause of chronic low back pain. The authors investigated the efficacy of pressure-controlled discography to determine its role in clinical decision-making for the management of patients with discogenic pain. Pressure-controlled discography was performed in 21 patients (51 discs) with pain-provocation, followed by post-discography computerized tomography scans. Pain response was classified as positive response and negative response, and measured with visual analog scale scores. Discographic findings were graded by the modified Dallas discogram scale. Elastance, pain provocation on intradiscal pressure, pressure and volume of initial pain response, and pain response intensity were statistically analyzed. Elastance showed significant differences between Grade 0 and Grade 4 and 5. Decreased elastance with positive pain response group was a good indicator to imply that disc degeneration presumably is a pain generator. Results of pain response were well correlated with intradiscal pressure but not with the amount of injected volume. Among 31 discs of Grade 4 and 5, 74% showed negative pain response and 26% showed positive response. It was concluded that pressure-controlled discography was useful to diagnose discogenic pain and excellent guide in decision-making for spinal operations.

Are "structural abnormalities" on magnetic resonance imaging a contraindication to the successful conservative treatment of chronic nonspecific low back pain?

STUDY DESIGN

Prospective study.

OBJECTIVE

To examine the association between structural abnormalities recorded on magnetic resonance imaging (MRI) and outcome after evidence-based conservative treatment in patients with chronic nonspecific low back pain (LBP).

SUMMARY OF BACKGROUND DATA

In most guidelines for the management of LBP, MRI is not recommended unless the diagnostic triage suggests serious spinal pathology or nerve root involvement for which surgical treatment is foreseen. This is because many structural changes seen on MRI appear to be as common in asymptomatic individuals as in people with LBP and are, therefore, considered of little value in either explaining the cause of pain or deciding the subsequent course of management. However, to our knowledge, no studies have assessed whether the presence of such MRI abnormalities influences the outcome of the conservative treatment that patients with chronic nonspecific LBP typically receive.

METHODS

T2-weighted, 4-mm spin-echo MRI sequences of the lumbar spine were obtained from 53 patients with chronic nonspecific LBP before a 3-month program of exercise therapy. Disc degeneration, disc bulging, high intensity zones, and endplate/bone marrow changes were assessed for each lumbar segment. Back pain (average and worst) and disability (Roland Morris score) were assessed before and after therapy, and 12 months later, and the improvements were examined in relation to the presence or absence of baseline MRI "abnormalities."

RESULTS

Eighty-nine percent of patients had severe disc degeneration (grade 4 or 5), 74% had disc bulging, 60% had high intensity zones, and 62% had endplate/bone marrow changes in at least 1 lumbar segment. Only 11% patients had none of these changes at any level. The MRI abnormalities showed only minimal association with baseline symptoms. In multivariate regression analyses, in which age, gender, and baseline symptoms were controlled for, only 1 significant association between the MRI variables and outcome was observed: the presence of a high intensity zone in any vertebral segment was associated with lower average pain at the 12-month follow-up (standardized beta -0.376, P = 0.006, 16.5% variance accounted for).

CONCLUSION

In the patient group examined, the presence of common "structural abnormalities" on MRI had no significant negative influence on the outcome after therapy.

Predictive value of MRI vertebral end-plate signal changes (MODIC) on outcome of surgically treated degenerative disc disease

OBJECTIVE

To assess the predictive value of MRI vertebral end-plate changes (Modic) on clinical outcome of surgically treated lumbar single-level degenerative disc disease (DDD).

METHODS

A cohort of 60 patients was included. Patient groups were similar in respect of age, gender and clinical presentation, allowing comparisons. Patient age ranged from 30 to 72 years (mean: 45.8 years). All patients suffered severe chronic low back pain for more than 6 months, with single-level symptomatic DDD. All patients experienced segmental instrumented interbody (n = 22) or posterolateral (n = 38) fusion. Clinical outcome was assessed by using a visual analog scale (VAS) and the functional disability scale of the Japanese Orthopaedic Association (JOA) for lumbar spine. The number of patients for each Modic group was as follows: Modic type 0, n = 15; Modic type I, n = 22; Modic type II, n = 14; and Modic type I/II, n = 9. Fusion rates were similar for each Modic group of patients. Mean follow-up was 14 months.

RESULTS

The pre-operative mean VAS improved by 53.5% (from 8.2+/-2.0 to 3.8+/-1.9, p < 0.05) and the pre-operative mean JOA score by 58% (from 5.5+/-2.1 to 11.0+/-2.4, p < 0.05). Patients harboring Modic type I changes improved much better than others (p < 0.05). Conversely, clinical outcome of patients presenting with Modic type II lesions was poor.

CONCLUSION

This study confirms instrumented fusion as an effective treatment in symptomatic lumbar DDD. Preoperative combination of low back pain of discal origin and severe DDD with Modic type I lesion on MRI may lead to excellent results after fusion in a large proportion of patients. Conversely, arthrodesis for patients harboring Modic type II abnormalities implicates smaller benefit of doubtful clinical significance.

Back pain and degenerative abnormalities in the spine of young elite divers: a 5-year follow-up magnetic resonance imaging study

Several studies have been published on disc degeneration among young athletes in sports with great demands on the back, but few on competitive divers; however, there are no long-term follow-up studies. Twenty elite divers between 10 and 21 years of age, with the highest possible national ranking, were selected at random without knowledge of previous or present back injuries or symptoms for an MRI study of the thoraco-lumbar spine in a 5-year longitudinal study. The occurrence of MRI abnormalities and their correlation with back pain were evaluated. Eighty-nine percent of the divers had a history of back pain and the median age at the first episode of back pain was 15 years. Sixty-five percent of the divers had MRI abnormalities in the thoraco-lumbar spine already at baseline. Only one diver without abnormalities at baseline had developed abnormalities at follow-up. Deterioration of any type of abnormality was found in 9 of 17 (53%) divers. Including all disc levels in all divers, the total number of abnormalities increased by 29% at follow-up, as compared to baseline. The most common abnormalities were reduced disc signal, Schmorl's nodes, and disc height reduction. Since almost all divers had previous or present back pain, a differentiated analysis of the relationship between pain and MRI findings was not possible. However, the high frequency of both back pain and MRI changes suggests a causal relationship. In conclusion, elite divers had high frequency of back pain at young ages and they run a high risk of developing degenerative abnormalities of the thoraco-lumbar spine, probably due to injuries to the spine during the growth spurt.

What is intervertebral disc degeneration, and what causes it?

STUDY DESIGN

Review and reinterpretation of existing literature.

OBJECTIVE

To suggest how intervertebral disc degeneration might be distinguished from the physiologic processes of growth, aging, healing, and adaptive remodeling.

SUMMARY OF BACKGROUND DATA

The research literature concerning disc degeneration is particularly diverse, and there are no accepted definitions to guide biomedical research, or medicolegal practice.

DEFINITIONS

The process of disc degeneration is an aberrant, cell-mediated response to progressive structural failure. A degenerate disc is one with structural failure combined with accelerated or advanced signs of aging. Early degenerative changes should refer to accelerated age-related changes in a structurally intact disc. Degenerative disc disease should be applied to a degenerate disc that is also painful.

JUSTIFICATION

Structural defects such as endplate fracture, radial fissures, and herniation are easily detected, unambiguous markers of impaired disc function. They are not inevitable with age and are more closely related to pain than any other feature of aging discs. Structural failure is irreversible because adult discs have limited healing potential. It also progresses by physical and biologic mechanisms, and, therefore, is a suitable marker for a degenerative process. Biologic progression occurs because structural failure uncouples the local mechanical environment of disc cells from the overall loading of the disc, so that disc cell responses can be inappropriate or "aberrant." Animal models confirm that cell-mediated changes always follow structural failure caused by trauma. This definition of disc degeneration simplifies the issue of causality: excessive mechanical loading disrupts a disc's structure and precipitates a cascade of cell-mediated responses, leading to further disruption. Underlying causes of disc degeneration include genetic inheritance, age, inadequate metabolite transport, and loading history, all of which can weaken discs to such an extent that structural failure occurs during the activities of daily living. The other closely related definitions help to distinguish between degenerate and injured discs, and between discs that are and are not painful.

A feasibility study of in vivo T1rho imaging of the intervertebral disc

PURPOSE

Recent studies have proposed that magnetic resonance (MR) T1rho relaxation time is associated with loss of macromolecules. The depletion of macromolecules in the matrix of the intervertebral disc may be an initiating factor in degenerative disc disease. The purpose of this study was to test the feasibility of quantifying T1rho relaxation time in phantoms and intervertebral discs of healthy volunteers using in vivo MR imaging at 3 T.

MATERIALS AND METHODS

A multislice T1rho spiral sequence was used to quantify T1rho relaxation time in phantoms with different agarose concentrations and in the intervertebral discs of 11 healthy volunteers (mean age=31.3 years; age range=23-60 years; gender: 5 females, 6 males).

RESULTS

The phantom studies demonstrated the feasibility of using spiral imaging at 3 T. The in vivo results indicate that the median T1rho value of the nucleus (116.6+/-21.4 ms) is significantly greater (P<0.05) than that of the annulus (84.1+/-11.7 ms). The correlations between the age of the volunteers and T1rho relaxation time in the nucleus (r2=-0.82; P=0.0001) and the annulus (r2=-0.37; P=0.04) were significant. A trend of decreasing T1rho values from L3-4 to L4-5 to L5-S1 was evident.

CONCLUSION

The results of this study suggest that in vivo T1rho quantification is feasible and may potentially be a clinical tool in identifying early degenerative changes in the intervertebral disc.

Towards standardized measurement of adverse events in spine surgery: conceptual model and pilot evaluation

Background

Independent of efficacy, information on safety of surgical procedures is essential for informed choices. We seek to develop standardized methodology for describing the safety of spinal operations and apply these methods to study lumbar surgery. We present a conceptual model for evaluating the safety of spine surgery and describe development of tools to measure principal components of this model: (1) specifying outcome by explicit criteria for adverse event definition, mode of ascertainment, cause, severity, or preventability, and (2) quantitatively measuring predictors such as patient factors, comorbidity, severity of degenerative spine disease, and invasiveness of spine surgery.

Methods

We created operational definitions for 176 adverse occurrences and established multiple mechanisms for reporting them. We developed new methods to quantify the severity of adverse occurrences, degeneration of lumbar spine, and invasiveness of spinal procedures. Using kappa statistics and intra-class correlation coefficients, we assessed agreement for the following: four reviewers independently coding etiology, preventability, and severity for 141 adverse occurrences, two observers coding lumbar spine degenerative changes in 10 selected cases, and two researchers coding invasiveness of surgery for 50 initial cases.

Results

During the first six months of prospective surveillance, rigorous daily medical record reviews identified 92.6% of the adverse occurrences we recorded, and voluntary reports by providers identified 38.5% (surgeons reported 18.3%, inpatient rounding team reported 23.1%, and conferences discussed 6.1%). Trained observers had fair agreement in classifying etiology of 141 adverse occurrences into 18 categories (kappa = 0.35), but agreement was substantial (kappa ≥ 0.61) for 4 specific categories: technical error, failure in communication, systems failure, and no error. Preventability assessment had moderate agreement (mean weighted kappa = 0.44). Adverse occurrence severity rating had fair agreement (mean weighted kappa = 0.33) when using a scale based on the JCAHO Sentinel Event Policy, but agreement was substantial for severity ratings on a new 11-point numerical severity scale (ICC = 0.74). There was excellent inter-rater agreement for a lumbar degenerative disease severity score (ICC = 0.98) and an index of surgery invasiveness (ICC = 0.99).

Conclusion

Composite measures of disease severity and surgery invasiveness may allow development of risk-adjusted predictive models for adverse events in spine surgery. Standard measures of adverse events and risk adjustment may also facilitate post-marketing surveillance of spinal devices, effectiveness research, and quality improvement.

Magnetic resonance imaging findings in dogs with thoracolumbar intervertebral disk disease: 69 cases (1997-2005)

OBJECTIVE

To determine magnetic resonance imaging (MRI) abnormalities in dogs with intervertebral disk disease (IVDD) and develop a classification scheme for IVDD in dogs based on MRI findings.

DESIGN

Retrospective case series.

ANIMALS

69 dogs.

PROCEDURE

Medical records of dogs admitted because of thoracolumbar IVDD in which MRI of T9 through L7 had been performed were reviewed.

RESULTS

A total of 759 intervertebral disk spaces were examined. Of these, 342 (45.1%) were classified as having a normal MRI appearance; the remaining 417 (54.9%) had various types of IVDD. Disk degeneration was identified in 276 disk spaces in 56 dogs, bulging of the intervertebral disk was identified in 37 disk spaces in 24 dogs, disk protrusion was identified in 54 disk spaces in 32 dogs, and disk extrusion was identified in 50 disk spaces in 48 dogs. Cartilage endplate changes were identified in 35 vertebrae in 17 dogs, and increased signal intensity of the spinal cord was identified in 21 dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Four types of IVDD (disk degeneration, bulging of the intervertebral disk, disk protrusion, and disk extrusion) were identified on the basis of MRI findings in dogs with thoracolumbar IVDD. We recommend that a standardized nomenclature be adopted for the various types of thoracolumbar IVDD in dogs.

Degenerative Erkrankungen der Wirbelsäule

GOAL

The aim of this article is to describe rare and often unrecognized causes of spinal pain syndromes.

METHOD

Intervertebral disc degeneration frequently appears in early adulthood and can have a symptomatic or asymptomatic course. This article discusses incidence, pathophysiology, imaging, and pain symptomatology involved in the origin of back pain.

RESULTS

Anulus tears are often found in asymptomatic individuals but could be implicated in lumbar pain symptomatology in correlation with the provocative discography. Transient disorders can lead to pseudarthrosis of the iliac bone and to degeneration or to a reactive hypermobility with intervertebral disc degeneration in the level above. Modic type 1 erosive osteochondrosis is characterized by bone marrow edema near the hyaline cartilage end plate, which mostly elicits severe pain and results in serious limitations in everyday activities. The most important differential diagnosis is spondylodiscitis. Schmorl's nodes can exhibit considerable surrounding bone marrow edema that can be mistaken for metastases. A combination of MRI and CT should be employed for the diagnostic work-up of fatigue fracture of the interarticular portion, which is often overlooked due to its location. Synovial cysts of the facet joints can lead to radicular symptoms. Insufficiency fracture of the sacrum is frequently mistaken for metastasis due to intense scintigraphic enhancement and its signal behavior in MRI. CT provides instructive information.

CONCLUSION

Differential diagnosis should include less common causes such as anulus tears, transient disorders, activated Schmorl's nodes, synovial cysts of the facet joints, fatigue fractures of the interarticular portion of the spine and the sacrum and distinguish from metastases in particular.

Validity and interobserver agreement of a new radiographic grading system for intervertebral disc degeneration: Part II. Cervical spine

A new radiographic grading system for a more objective assessment of lumbar intervertebral disc degeneration has been described and tested in Part I of this study. The aim of the present Part II of the study was to adapt this system to the cervical spine, and to test it for validity and interobserver agreement. Some modifications of the grading system described in Part I were necessary to make it applicable to the cervical spine. Its basic structure, however, stayed untouched. The three variables "Height Loss", "Osteophyte Formation" and "Diffuse Sclerosis" first have to be graded individually. Then, the "Overall Degree of Degeneration" is assigned on a four-point scale from 0 (no degeneration) to 3 (severe degeneration). For validation, the radiographic degrees of degeneration of 28 cervical discs were compared to the respective macroscopic ones, which were defined as "real" degrees of degeneration. The interobserver agreement was determined between one experienced and one unexperienced observer using the radiographs of 57 cervical discs. Quadratic weighted Kappa coefficients (kappa) with 95% confidence limits (95% CL) were used for statistical evaluation. The validation of the new version of the radiographic grading system showed a moderate agreement with the "real", macroscopic overall degree of degeneration (kappa=0.599, 95% CL 0.421-0.786). In 64% of all discs the "real" overall degree of degeneration was underestimated but never overestimated. This underestimation, however, was much less pronounced and the Kappa coefficients were significantly higher for the three variables: Height Loss, Osteophyte Formation, and Diffuse Sclerosis separately. The agreement between the radiographic ratings of the experienced and the unexperienced observer was substantial for the overall degree of degeneration (kappa=0.688, 95% CL 0.580-0.796), almost perfect for the variable, Height Loss, moderate for Osteophyte Formation and fair for Diffuse Sclerosis. In conclusion, we believe that the new version of the radiographic grading system is a sufficiently valid and reliable tool to quantify the degree of degeneration of individual cervical intervertebral discs. In comparison to the version for the lumbar spine described in Part I, however, a slightly higher tendency to underestimate the "real" overall degree of degeneration and somewhat higher interobserver differences have to be expected.

Trauma induces apoptosis in human thoracolumbar intervertebral discs

Background

Vertebral fractures resulting from high energy trauma often comprise the risk of posttraumatic degenerative changes in the affected intervertebral discs (IVD). Particularly in conservatively treated patients, or in cases after implant removal of an exclusively posterior stabilization, consecutive disc degeneration and the associated functional losing of the spinal segment clearly represent detrimental treatment results. In this regard, apoptosis of IVD cells has been suggested to be involved in the critical changes of the extracellular matrix.

Methods

To investigate whether fractures of the vertebrae induce apoptosis in the affected IVD, disc tissue from patients (n = 17) undergoing open reduction and internal fixation of thoracolumbar spine fractures were analysed in regards to caspase activity, apoptosis-receptor expression levels and gene expression of apoptosis-regulating proteins such as Bax and Bcl-2. Healthy IVD tissue (n = 3) obtained from patients undergoing surgical resection of adjacent vertebrae were used as control samples.

Results

In contrast to healthy control IVD tissues, samples from traumatic thoracolumbar IVD showed positive TUNEL staining and a significant increase of caspase-3/7 activity. Interestingly, analyses of the initiator caspase-8 and -9 revealed significantly increased activation levels compared to control values, suggesting the coexistent activation of both the extrinsic (receptor-mediated) and intrinsic (mitochondria-mediated) apoptosis pathway. Accordingly, expression levels of the Fas receptor (FasR) mRNA were significantly increased. Although the TNF receptor I (TNFR I) was only slightly upregulated, corresponding TNFα from trauma IVD presented significantly increased mRNA expression values. Furthermore, traumatic IVD cells demonstrated significantly reduced expression of the mitochondria-bound anti-apoptotic Bcl-2, thereby maintaining baseline transcriptional levels of the pro-apoptotic Bax protein when compared to control IVD cells.

Conclusion

Our data suggest that thoracolumbar fractures induce early caspase-dependent apoptosis in IVD cells of the affected intervertebral disc, in part, by downregulation of the anti-apoptotic protein Bcl-2 (intrinsic apoptosis pathway), as well as signalling via the death receptor complex (TNFR I and FasR).

Assessment of human disc degeneration and proteoglycan content using T1rho-weighted magnetic resonance imaging

STUDY DESIGN

T1rho relaxation was quantified and correlated with intervertebral disc degeneration and proteoglycan content in cadaveric human lumbar spine tissue.

OBJECTIVE

To show the use of T1rho-weighted magnetic resonance imaging (MRI) for the assessment of degeneration and proteoglycan content in the human intervertebral disc.

SUMMARY OF BACKGROUND DATA

Loss of proteoglycan in the nucleus pulposus occurs during early degeneration. Conventional MRI techniques cannot detect these early changes in the extracellular matrix content of the disc. T1rho MRI is sensitive to changes in proteoglycan content of articular cartilage and may, therefore, be sensitive to proteoglycan content in the intervertebral disc.

METHODS

Intact human cadaveric lumbar spines were imaged on a clinical MR scanner. Average T1rho in the nucleus pulposus was calculated from quantitative T1rho maps. After MRI, the spines were dissected, and proteoglycan content of the nucleus pulposus was measured. Finally, the stage of degeneration was graded using conventional T2 images.

RESULTS

T1rho decreased linearly with increasing degeneration (r = -0.76, P < 0.01) and age (r = -0.76, P < 0.01). Biochemical analysis revealed a strong linear correlation between T1rho and sulfated-glycosaminoglycan content. T1rho was moderately correlated with water content.

CONCLUSIONS

Results from this study suggest that T1rho may provide a tool for the diagnosis of early degenerative changes in the disc. T1rho-weighted MRI is a noninvasive technique that may provide higher dynamic range than T2 and does not require a high static field or exogenous contrast agents.

Effect of aging and degeneration on disc volume and shape: A quantitative study in asymptomatic volunteers

Debate continues on the effect of disc degeneration and aging on disc volume and shape. So far, no quantitative in vivo MRI data is available on the factors influencing disc volume and shape. The objective of this MRI study was to quantitatively investigate changes in disc height, volume, and shape as a result of aging and/or degeneration omitting pathologic (i.e., painful) disc alterations. Seventy asymptomatic volunteers (20-78 years) were investigated with sagittal T1- and T2-weighted MR-images encompassing the whole lumbar spine. Disc height was determined by the Dabbs method and the Farfan index. Disc volume was calculated by the Cavalieri method. For the disc shape the "disc convexity index" was calculated by the ratio of central disc height and mean anterior/posterior disc height. Disc height, disc volume, and the disc convexity index measurements were corrected for disc level and the individuals age, weight, height, and sex in a multilevel regression analysis. Multilevel regression analysis showed that disc volume was negatively influenced by disc degeneration (p < 0.001) and positively correlated with body height (p < 0.001) and age (p < 0.01). Mean disc height and the disc convexity index were negatively influenced by disc degeneration but not by gender, weight, and height. Disc height was positively correlated with age (p < 0.01). From the results of this study, it can be concluded that disc degeneration generally results in a decrease of disc height and volume as well as a less convex disc shape. In the absence of disc degeneration, however, age tends to result in an inverse relationship on disc height, volume, and shape.

Risk factor for unsatisfactory outcome after lumbar foraminal and far lateral microdecompression

STUDY DESIGN

A retrospective study of consecutive patients who underwent microdecompression for far lateral disc or foraminal stenosis.

OBJECTIVES

To evaluate the risk factors for unsatisfactory outcome.

SUMMARY OF BACKGROUND DATA

There has been no detailed analysis of postoperative radicular pain, although it is not infrequent following foraminal and far lateral microdecompression.

METHODS

A total of 184 patients, who were followed up for more than 2 years, were reviewed. Microdecompression was performed through lateral intermuscular approach. In cases of double herniation (combination of intracanalicular disc at the same level), additional intracanalicular decompression was simultaneously performed. The unsatisfactory outcomes included persistent or recurrent leg pain, based on the Japanese Orthopedic Association leg pain score, and revision surgery at the same level. The potential risk factors, including gender, age, symptom period, preoperative radiologic and intraoperative findings, were determined.

RESULTS

The average follow-up period was 38.4 months, with a maximum 70 months. Forty of the 184 patients (21.7%) had persistent or recurrent leg pain, with nine requiring revision surgeries. The statistically significant risk factor for unfavorable outcomes was double herniation, with odds ratio of 2.89 (P = 0.004).

CONCLUSION

Facet preserving microdecompression is an effective method for foraminal and far lateral root compression. However, in cases of double herniation, total facetectomy is preferable.

Imaging intervertebral disc degeneration

Magnetic resonance imaging provides excellent anatomic detail of spinal tissues, but fails to provide the type of information that permits a definitive diagnosis in many patients with back pain. New imaging strategies that can be applied to the study of intervertebral disc degeneration include diffusion-weighted imaging, magnetic resonance imaging, diffusion tensor imaging, magnetic resonance spectroscopy, functional magnetic resonance imaging, dynamic computed tomography and magnetic resonance imaging, and T2 relaxometry. With dynamic imaging, the relative motions of normal and degenerated lumbar motion segments can be evaluated noninvasively. With further evaluation of the technique, hypermobile segments may be distinguishable from those with normal relative motion. T2 measurements obtained by T2 relaxometry appear to have important advantages with regard to spinal imaging because this modality provides a continuous and objective measure of the content of free water in the disc, which decreases with aging and degeneration. Anatomic imaging of the spine is highly accurate in the evaluation of nonmechanical causes of back pain and less beneficial in the evaluation of back pain that is due to mechanical causes. The development of functional imaging strategies of the spine will likely improve the management of patients with back pain. This article outlines the current magnetic resonance imaging protocols for intervertebral disc degeneration, indicates deficiencies in current imaging, and describes functional imaging strategies for the spine that will likely improve the evaluation of patients with back pain. It also reviews recent published articles on magnetic resonance imaging and computed tomographic imaging of the spine and details the results of studies that have explored the future potential of spine imaging.

Relevance of in vitro and in vivo models for intervertebral disc degeneration

Models available for the study of intervertebral disc degeneration are designed to answer many important questions. In vitro biologic models employ a variety of cell, tissue, or organ culture techniques with culture conditions that partially mimic the cellular environment of the degenerated human intervertebral disc. In vitro biomechanical models include intervertebral disc or motion-segment loading experiments as well as finite element modeling techniques. The literature describes numerous in vivo animal models for use in the study of intervertebral disc degeneration, each of which has its own advantages and disadvantages. Human-subject studies have included the use of magnetic resonance imaging and other techniques to assess diffusion into the intervertebral disc, to measure intradiscal pressure, to conduct kinematic or stiffness studies of lumbar motion segments, and to evaluate muscular forces on the spine. Although all of these studies are helpful in answering specific questions, their relevance in assessing disc degeneration in patients with symptoms of discogenic pain must be carefully considered.

In vivo quantification of human lumbar disc degeneration using T(1rho)-weighted magnetic resonance imaging

Diagnostic methods and biomarkers of early disc degeneration are needed as emerging treatment technologies develop (e.g., nucleus replacement, total disc arthroplasty, cell therapy, growth factor therapy) to serve as an alternative to lumbar spine fusion in treatment of low back pain. We have recently demonstrated in cadaveric human discs an MR imaging and analysis technique, spin-lock T(1rho)-weighted MRI, which may provide a quantitative, objective, and non-invasive assessment of disc degeneration. The goal of the present study was to assess the feasibility of using T(1rho) MRI in vivo to detect intervertebral disc degeneration. We evaluated ten asymptomatic 40-60-year-old subjects. Each subject was imaged on a 1.5 T whole-body clinical MR scanner. Mean T(1rho) values from a circular region of interest in the center of the nucleus pulposus were calculated from maps generated from a series of T(1rho)-weighted images. The degenerative grade of each lumbar disc was assessed from conventional T(2)-weighted images according to the Pfirmann classification system. The T(1rho) relaxation correlated significantly with disc degeneration (r=-0.51, P<0.01) and the values were consistent with our previous cadaveric study, in which we demonstrated correlation between T(1rho) and proteoglycan content. The technique allows for spatial measurements on a continuous rather than an integer-based scale, minimizes the potential for observer bias, has a greater dynamic range than T(2)-weighted imaging, and can be implemented on a 1.5 T clinical scanner without significant hardware modifications. Thus, there is a strong potential to use T(1rho) in vivo as a non-invasive biomarker of proteoglycan loss and early disc degeneration.

The association between negative affect and opioid analgesia in patients with discogenic low back pain

Comprised mainly of depression, anxiety, and high neuroticism, psychopathology diminishes the effectiveness of many chronic pain treatments. But, it is not known if it is associated with diminished opioid analgesia in patients with chronic, noncancer pain. We tested the hypothesis that psychopathology diminishes opioid analgesia in patients with discogenic low back pain in 60 patients not on opioids in a double blind, placebo controlled, random crossover designed trial. Patients were stratified into three groups of psychological symptom severity (LOW, MOD, and HIGH), based on composite scores on depression, anxiety for pain, and neuroticism scales. Subjects were given intravenous morphine (4-6mg dosed by ideal body weight) and placebo in random order on separate visits, and completed serial pain ratings over three hours at each session. With 20 subjects per group, there were nonsignificant differences between groups in the distribution of age, gender, baseline pain (avg. 6.1/10), radicular pain, and morphine dose (5.0mg). For morphine analgesia, using a total pain relief calculation (TOTPAR), the LOW group had 65.1% TOTPAR vs. 41.0% in the HIGH group, P=.026. For placebo analgesia the LOW group had 7.7% TOTPAR vs. 23.5% in the HIGH group, P=.03. A morphine minus placebo analgesia calculation revealed 59.2% TOTPAR in the LOW group vs. 21.7% in the HIGH group, P=.0001. High levels of psychopathology are associated with diminished opioid analgesia in patients with discogenic low back pain. These results have implications for the prescription of oral opioids to patients with chronic low back pain and psychopathology.

Correlation of HR-MAS spectroscopy derived metabolite concentrations with collagen and proteoglycan levels and Thompson grade in the degenerative disc

STUDY DESIGN

A quantitative high-resolution magic angle spinning (HR-MAS) NMR study of human lumbar discs was conducted to determine biomarkers of disc degeneration.

OBJECTIVES

To correlate HR-MAS quantification of compounds relevant to human lumbar disc degeneration to conventional methods of disc grading such as Thompson grading and biochemical analysis.

SUMMARY OF BACKGROUND DATA

It has been shown that there is poor correlation between MRI and CT morphologic findings, spinal biomechanics, and patient symptoms in degenerative disc disease and low back pain. There is a need for an objective, quantitative measurement of biochemical status, morphology, and function.

METHODS

A total of 17 cadaveric human lumbar intervertebral discs were harvested from patients ranging from 20 to 85 years of age. Quantitative HR-MAS data were acquired, and proteoglycan and collagen biochemical analyses were conducted on 3-mm biopsy punches taken from the anulus fibrosus and nucleus pulposus of each sample. HR-MAS data were fitted and analyzed for hydroxyproline (3.42 ppm), glycine (3.56 ppm), and the N-acetyl peak (2.04 ppm) associated with proteoglycans in comparison with an internal standard. These concentrations were then compared directly to biochemical analyses and Thompson grade.

RESULTS

HR-MAS data correlated well with Thompson grade (P < 0.001). An increase was seen in the levels of unbound hydroxyproline and glycine in annular tissue, which is directly associated to collagen breakdown. This trend also correlates with the changes of total collagen measured by a collagen biochemical assay. HR-MAS also detected a decrease in concentration of nucleus pulposus proteoglycans with degeneration. This proteoglycan decrease was verified by a standard proteoglycan biochemical assay.

CONCLUSIONS

Changes in disc chemical composition can be accurately quantified using quantitative HR-MAS NMR spectroscopy ex vivo. This noninvasive method of qualitatively and quantitatively assessing disc degeneration supports the utility of these biomarkers and underlines the need for developing in vivo magnetic resonance spectroscopic imaging (MRSI) for characterizing intervertebral disc degeneration.

Comparison of discographic findings in asymptomatic subject discs and the negative discs of chronic LBP patients: can discography distinguish asymptomatic discs among morphologically abnormal discs?

BACKGROUND CONTEXT

Lumbar discography has been widely used for evaluating discogenic low back pain (LBP). Comparison of pain responses from suspected symptomatic discs with pain responses from asymptomatic negative discs is routine. However, the ability of discography to distinguish asymptomatic morphologically abnormal discs from those that are symptomatic has been understudied. In addition, the discographic characteristics of negative discs in patients with chronic discogenic LBP have not been reported. Criteria for negative morphologically abnormal discs may be valuable for excluding discs from further treatment and examination.

PURPOSE

To determine if discography can distinguish asymptomatic discs among morphologically abnormal discs in patients with suspected chronic discogenic LBP and establish the standard characteristics of negative discs.

STUDY DESIGN/SETTING

Prospective, experimental with control group.

PATIENT SAMPLE

Fifty-five discs from a control group of 16 healthy volunteers without current back pain (11 men, 5 women, 32-61 years of age, mean age: 47 years) and 282 discs from a patient group of 90 LBP patients (59 men, 31 women, 20-70 years of age, mean age: 44.7 years) were recruited.

METHODS

Discography was performed using a pressure-controlled manometric technique with an injection rate of 0.05 mL/s and a 3.5 mL restricted total volume. Concordance was rated as none/unfamiliar, or familiar. Pain was rated via a 0-10 numerical rating scale (NRS). The pressure and volume at which pain was evoked and NRS pain responses at 15, 30, and 50 psi were recorded. Annular disruption grade was rated during the procedure by computed tomography discography and fluoroscopic imaging. Negative discogram required no pain described by the participant as "familiar," with no pain responses >or=6/10 NRS at pressures <or=50 psi above opening pressure and <or=3.5 mL total injected volume. Patient discs were partitioned into two subgroups based on discographic findings: Neg-D (negative discs) and Pos-D (positive discs). Only discs with Grade 3 annular tears (Dallas Discogram Scale) were included in the study.

RESULTS

Among 55 asymptomatic control group discs, 32 (58.2%) exhibited Grade 3 annular tear. All discs in the asymptomatic control group satisfied negative response criteria. Among 282 patient group discs, 199 (70.6%) exhibited Grade 3 annular tear. Of 199 discs with Grade 3 annular tears, 104 (52.3%) satisfied negative response criteria and were categorized as the Neg-D group. The other 95 discs were categorized as a Pos-D group. Patients showed significantly lower pain tolerance relative to control subjects (p<.05). The control and Neg-D groups showed similar pressures and volumes at which pain was initially evoked. Mean control group pain scores were 0.47 NRS at 15 psi and 1.58 NRS at 50 psi. Mean Neg-D group pain scores were 0.11 NRS at 15 psi and 1.1 NRS at 50 psi. Discographic findings for the Pos-D group were significantly different from those of the control and Neg-D groups (p<.001).

CONCLUSIONS

Pain tolerance was significantly lower in patients relative to asymptomatic subjects. Negative patient discs and asymptomatic subject discs showed similar characteristics. Pressure-controlled manometric discography using strict criteria may distinguish asymptomatic discs among morphologically abnormal discs with Grade 3 annular tears in patients with suspected chronic discogenic LBP.

Validity and interobserver agreement of a new radiographic grading system for intervertebral disc degeneration: Part I. Lumbar spine

Many different radiographic grading systems for disc degeneration are described in literature. However, only a few of them are tested for interobserver agreement and none for validity. Furthermore, most of them are based on a subjective terminology. The aim of this study, therefore, is to combine these systems to a new one in which all subjective terms are replaced by more objective ones and to test this new system for validity and interobserver agreement. Since lumbar and cervical discs need to be graded differently, this study was divided into the present Part I for the lumbar and a Part II for the cervical spine. The new radiographic grading system covers the three variables "Height Loss", "Osteophyte Formation" and "Diffuse Sclerosis". On lateral and postero-anterior radiographs, each of these three variables first has to be graded individually. Then, the "Overall Degree of Degeneration" is assigned on a four-point scale from 0 (no degeneration) to 3 (severe degeneration). For validation, the radiographic degrees of degeneration of 44 lumbar discs were compared to the respective macroscopic ones, which were defined as "real" degrees of degeneration. The agreement between observers with different levels of experience was determined using the radiographs of 84 lumbar discs. Agreement was quantified using quadratic weighted Kappa coefficients (Kappa) with 95% confidence limits (95% CL). The validation of the new radiographic grading system revealed a substantial agreement between the radiographic and the "real" macroscopic overall degree of degeneration (Kappa=0.714, 95% CL: 0.587-0.841). The radiographic grades, however, tended to be slightly lower than the "real" ones. The interobserver agreement was substantial for all the three variables and for the overall degree of degeneration (Kappa=0.787, 95% CL: 0.702-0.872). However, the inexperienced observer tended to assign slightly lower degrees of degeneration than the experienced one. In conclusion, we believe that the new radiographic grading system is an almost objective, valid and reliable tool to quantify the degree of degeneration of individual lumbar intervertebral discs. However, the user should always remember that the "real" degree of degeneration tends to be underestimated and that slight differences between the ratings of observers with different levels of experience have to be expected.

Review of existing grading systems for cervical or lumbar disc and facet joint degeneration

The aim of this literature review was to present and to evaluate all grading systems for cervical and lumbar disc and facet joint degeneration, which are accessible from the MEDLINE database. A MEDLINE search was conducted to select all articles presenting own grading systems for cervical or lumbar disc or facet joint degeneration. To give an overview, these grading systems were listed systematically depending on the spinal region they refer to and the methodology used for grading. All systems were checked for reliability tests and those recommended for use having an interobserver Kappa or Intraclass Correlation Coefficient >0.60 if disc degeneration was graded and >0.40 if facet joint degeneration was graded. MEDLINE search revealed 42 different grading systems. Thirty of these were used to grade lumbar spine degeneration, ten were used to grade cervical spine degeneration and two were used to grade both. Thus, the grading systems for the lumbar spine represented the vast majority of all 42 grading systems. Interobserver reliability tests were found for 12 grading systems. Based on their Kappa or Intraclass Correlation Coefficients nine of these could be recommended for use and three could not. All other systems could neither be recommended nor not be recommended since reliability tests were missing. These systems should therefore first be tested before use. The design of the grading systems varied considerably. Five grading systems were beginning with the lowest degree of degeneration, 37, however, with the normal, not degenerated state. A 5-grade scale was used in six systems, a 4-grade scale in 24, a 3-grade scale in eight and a 2-grade scale in three systems. In 15 cases the normal, not degenerated state was assigned to "grade 0", in another 15 cases, however, this state was assigned to "grade 1". This wide variety in the design of the grading systems makes comparisons difficult and may easily lead to confusion. We would therefore recommend to define certain standards. Our suggestion would be to use a scale of three to five grades, to begin the scale with the not degenerated state and to assign this state to "grade 0".

Magnetic resonance imaging of the lumbar spine in asymptomatic professional fast bowlers in cricket

Low back injuries account for the greatest loss of playing time for professional fast bowlers in cricket. Previous radiological studies have shown a high prevalence of degeneration of the lumbar discs and stress injuries of the pars interarticularis in elite junior fast bowlers. We have examined MRI appearance of the lumbar spines of 36 asymptomatic professional fast bowlers and 17 active control subjects. The fast bowlers had a relatively high prevalence of multi-level degeneration of the lumbar discs and a unique pattern of stress lesions of the pars interarticularis on the non-dominant side. The systems which have been used to classify the MR appearance of the lumbar discs and pars were found to be reliable. However, the relationship between the radiological findings, pain and dysfunction remains unclear.

Intradiscal electrothermal treatment for chronic lower back pain patients with internal disc disruption

Chronic lower back pain is one of the most common musculoskeletal problems; it is also the most expensive industrial injury. Not surprisingly, many treatments have been developed to combat this expensive and debilitating condition. One of these, intradiscal electrothermal treatment (IDET), was developed for patients with chronic discogenic lower back pain who failed to improve with any of the wide variety of non- surgical treatments. The present study sought to evaluate the efficacy of IDET for patients with chronic lower back pain. Twenty-five patients were enrolled in this prospective study; the patients received IDET between June 2001 and June 2003. MRI was used to confirm the diagnosis of internal disc disruption in all patients. The patients then underwent a pre-operative provocative test and discography. The follow-up duration was at least 1 year in all cases, and the visual analogue scale, recovery rate, and satisfaction of each patient were evaluated. The average age of the patients was 32 years (age range 18 to 49 years), and the patient group was 33% male and 67% female. Of the 25 patients, 5 underwent lumbar fusion surgery within 1 year of IDET. After IDET, 8 patients (32%) reported more pain than before, 14 patients (56%) reported less pain, and 3 patients (12%) experienced no change. Twelve patients (48%) were satisfied with IDET, 11 (44%) were dissatisfied, and 2 (8%) were undecided about the treatment. At least 1 year after IDET, nearly half the study patients were dissatisfied with their medical outcome. Consequently, 5 patients (20%) underwent fusion surgery at 1 year after IDET. Although other studies have shown good results with IDET for at least 2 years, this investigation suggests the IDET may be somewhat less effective. In order to firmly establish the efficacy of IDET for treating chronic discogenic lower back pain, additional studies with larger numbers of patients evaluated over longer time periods are recommended.

Comparison of discographic findings in asymptomatic subject discs and the negative discs of chronic LBP patients: can discography distinguish asymptomatic discs among morphologically abnormal discs?

BACKGROUND CONTEXT

Lumbar discography has been widely used for evaluating discogenic low back pain (LBP). Comparison of pain responses from suspected symptomatic discs with pain responses from asymptomatic negative discs is routine. However, the ability of discography to distinguish asymptomatic morphologically abnormal discs from those that are symptomatic has been understudied. In addition, the discographic characteristics of negative discs in patients with chronic discogenic LBP have not been reported. Criteria for negative morphologically abnormal discs may be valuable for excluding discs from further treatment and examination.

PURPOSE

To determine if discography can distinguish asymptomatic discs among morphologically abnormal discs in patients with suspected chronic discogenic LBP and establish the standard characteristics of negative discs.

STUDY DESIGN/SETTING

Prospective, experimental with control group.

PATIENT SAMPLE

Fifty-five discs from a control group of 16 healthy volunteers without current back pain (11 men, 5 women, 32-61 years of age, mean age: 47 years) and 282 discs from a patient group of 90 LBP patients (59 men, 31 women, 20-70 years of age, mean age: 44.7 years) were recruited.

METHODS

Discography was performed using a pressure-controlled manometric technique with an injection rate of 0.05 mL/s and a 3.5 mL restricted total volume. Concordance was rated as none/unfamiliar, or familiar. Pain was rated via a 0-10 numerical rating scale (NRS). The pressure and volume at which pain was evoked and NRS pain responses at 15, 30, and 50 psi were recorded. Annular disruption grade was rated during the procedure by computed tomography discography and fluoroscopic imaging. Negative discogram required no pain described by the participant as "familiar," with no pain responses >or=6/10 NRS at pressures <or=50 psi above opening pressure and <or=3.5 mL total injected volume. Patient discs were partitioned into two subgroups based on discographic findings: Neg-D (negative discs) and Pos-D (positive discs). Only discs with Grade 3 annular tears (Dallas Discogram Scale) were included in the study.

RESULTS

Among 55 asymptomatic control group discs, 32 (58.2%) exhibited Grade 3 annular tear. All discs in the asymptomatic control group satisfied negative response criteria. Among 282 patient group discs, 199 (70.6%) exhibited Grade 3 annular tear. Of 199 discs with Grade 3 annular tears, 104 (52.3%) satisfied negative response criteria and were categorized as the Neg-D group. The other 95 discs were categorized as a Pos-D group. Patients showed significantly lower pain tolerance relative to control subjects (p<.05). The control and Neg-D groups showed similar pressures and volumes at which pain was initially evoked. Mean control group pain scores were 0.47 NRS at 15 psi and 1.58 NRS at 50 psi. Mean Neg-D group pain scores were 0.11 NRS at 15 psi and 1.1 NRS at 50 psi. Discographic findings for the Pos-D group were significantly different from those of the control and Neg-D groups (p<.001).

CONCLUSIONS

Pain tolerance was significantly lower in patients relative to asymptomatic subjects. Negative patient discs and asymptomatic subject discs showed similar characteristics. Pressure-controlled manometric discography using strict criteria may distinguish asymptomatic discs among morphologically abnormal discs with Grade 3 annular tears in patients with suspected chronic discogenic LBP.

Characterization of intervertebral disc degeneration by high-resolution magic angle spinning (HR-MAS) spectroscopy

The goal of this study was to determine the ability of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy to distinguish different stages of intervertebral disc degeneration (IVDD). 17 discs were removed from human cadavers and analyzed them using 1D and 2D (total correlation spectroscopy (TOCSY)) (1)H HR-MAS spectroscopy, and T(1) and T(2) relaxation time measurements to determine the chemical composition and changes in chemical environment of discs with increasing levels of degeneration (Thompson grade). Among the significant findings were that spectra were very similar for samples taken from annular and nuclear regions of discs, and that visually apparent changes were observed in the spectra of the annular and nuclear samples from discs with increasing Thompson grade. Area ratios of the N-acetyl to choline (Cho) regions, and Cho to carbohydrate (Carb) regions of the spectra allowed us to discriminate between discs of increasing Thompson grade with minimal overlap of individual ratios. Changes in T(1) and T(2) relaxation times of the chemical constituents of disc spectra were not significantly correlated to the degree of degeneration. The results of this study support the feasibility of using in vivo spectroscopy for detecting chemical changes associated with disc degeneration.

Upright, weight-bearing, dynamic-kinetic MRI of the spine: initial results

The potential relative beneficial aspects of upright, weight-bearing (pMRI), dynamic-kinetic (kMRI) spinal imaging over that of recumbent MRI (rMRI) include the revelation of occult spinal disease dependent on true axial loading, the unmasking of kinetic-dependent spinal disease and the ability to scan the patient in the position of clinically relevant signs and symptoms. This imaging unit under study also demonstrated low claustrophobic potential and yielded comparatively high resolution images with little motion/magnetic susceptibility/chemical shift artifact. Overall, it was found that rMRI underestimated the presence and maximum degree of gravity-dependent spinal pathology and missed altogether pathology of a dynamic nature, factors that are optimally revealed with p/kMRI. Furthermore, p/kMRI enabled optimal linkage of the patient's clinical syndrome with the medical imaging abnormality responsible for the clinical presentation, thereby allowing for the first time an improvement at once in both imaging sensitivity and specificity.

Lumbar Disk Herniation: Do MR Imaging Findings Predict Recurrence after Surgical Diskectomy?

PURPOSE

To retrospectively evaluate if the degree of disk degeneration and disk herniation volume at magnetic resonance (MR) imaging are risk factors for recurrent disk herniation.

MATERIALS AND METHODS

The institutional review board permits such retrospective studies, and individual informed consent was not required. MR imaging findings obtained before initial diskectomy in 30 patients (mean age, 42.8 years; 10 women, 20 men) with recurrent disk herniation (study group) and 30 patients (mean age, 42.2 years; nine women, 21 men) without recurrence for at least 2 years after surgery (control group) were compared. Disk degeneration was assessed on T2-weighted sagittal MR images with a five-point grading system (grade I indicated no degeneration; grade II, horizontal hypointense bands within disk; grade III, inhomogeneous disk with intermediate signal intensity; grade IV, no distinction between inner and outer parts of disk; and grade V, collapsed hypointense disk). Disk herniation was classified as representing protrusion, extrusion, or sequestration. The volume of both the affected intervertebral disk and the herniated disk material was measured. Qualitative and quantitative analyses were performed by two readers. The chi(2) test was used for comparison of categorical variables. For comparison of disk degeneration and volumes between patients with and those without recurrence, a paired two-tailed t test was used. Odds ratios based on the extent of disk degeneration were calculated for the entire sample.

RESULTS

Advanced disk degeneration (grades IV and V) was significantly less frequent in the study group than in the control group (P < .006). The risk of recurrent disk herniation decreased by a factor of 3.4 for each increase in grade of disk degeneration (odds ratio: 3.58; 95% confidence interval: 1.3, 9.6; P = .011). Mean disk herniation volume as a percentage of intervertebral disk volume was 10.59% +/- 3.41 in the study group and 11.56% +/- 3.84 in the control group. This difference was not significant (P = .31).

CONCLUSION

Minor disk degeneration but not herniation volume represents a risk factor for the recurrence of disk herniation after diskectomy.

Correlation of radiographic and MRI parameters to morphological and biochemical assessment of intervertebral disc degeneration

Degenerative disc disease (DDD) is a common finding in MRI scans and X-rays. However, their correlation to morphological and biochemical changes is not well established. In this study, radiological and MRI parameters of DDD were assessed and compared with morphological and biochemical findings of disc degeneration. Thirty-nine human lumbar discs (L1-S1), age 19-86 years, were harvested from eight cadavers. Within 48 h postmortem, MRIs in various spin-echo sequences and biplanar radiographs of intact spines were obtained. Individual discs with endplates were then sectioned in the mid-sagittal plane and graded according to the morphological appearance. Samples from the nucleus of each disc were harvested for biochemical analysis including water and proteoglycan contents. On MRIs, T2-signal intensity, Modic changes, disc extension beyond the interspace (DEBIT), nucleus pulposus shape, annular tears, osteophytes and endplate integrity were graded. On radiographs, an independent observer classified the parameters disc height, endplate sclerosis, osteophytes, Schmorl's nodes, intradiscal calcifications and endplate shape. General linear-regression models were used for statistical analysis. Backward elimination with a 10% significance cut-off level was used to identify the most significant parameters, which then were summed to create composite scores for radiography, MRI and the combination of both methods. The grading was performed by three observers, and a reliability analysis using Cronbach's alpha model was used to control interobserver agreement. The three radiographic parameters height-loss, osteophytes and intradiscal calcifications correlated significantly with the morphological degree of degeneration (p<0.001, R2=642). Significant differences of even one morphological grade could also be differentiated in the composite radiological score (p<0.05), except at the extremes between grades 1 and 2 and grades 4 and 5. All MRI parameters correlated significantly with the morphological grade (p<0.05); however Modic changes, T2-intensity and osteophytes accounted for 83% of the variation in the data. T2-signal intensity correlated significantly with H2O and proteoglycan content (p<0.001), and was best for detecting highly degenerated discs. Regression showed that the combined score was better correlated with the morphological grade (p<0.001, R2=775) than either the composite radiographic (p<0.001, R2=642) or composite MRI (p<0.001, R2=696) alone. Based on the combined score, a backwards elimination of the regression was performed, in which the parameters Modic changes, and T2-intensity loss (MRI) as well as calcifications (X-ray) accounted for 87% of the variability. The interobserver validation showed a high correlation for all three scores (Cronbach's alpha values ranging from 0.95 to 0.97).

CONCLUSION

Selective imaging parameters and a newly created scoring scheme were found to correlate with disc degeneration as determined in a morphological manner. Surprisingly, radiographic parameters were able to distinguish different stages of degeneration, whereas MRI could only detect advanced stages of disc degeneration. We conclude that X-rays may remain a cost-effective, non-invasive in vivo-grading method to detect early disc degeneration, and, combined with MRI, correlate best with morphological and biochemical assessment of disc degeneration.

Disc degeneration in the rabbit: a biochemical and radiological comparison between four disc injury models

STUDY DESIGN

A biochemical and radiologic comparison of 4 disc injury models to produce disc degeneration in the rabbit was carried out in 2 experiments.

OBJECTIVES

To develop a reliable animal model of intervertebral disc degeneration.

SUMMARY OF BACKGROUND DATA

In order to study various interventions for retarding or preventing disc degeneration, a reliable animal model of disc degeneration is needed.

METHODS

First experiment: 7 New Zealand white rabbits (1 year old, 3.5-4.5 kg body weight) were used to test 4 different disc injury models; intradiscal injection of Camptothecin (an apoptotic agent) using a 23-gauge needle at L2-L3, nucleus aspiration using a 21-gauge needle at L3-L4, 3 anulus punctures using a 21-gauge needle at L4-L5, and 1 anulus puncture using a 18-gauge needle at L5-L6. The L1-L2 level was used as a control. Rabbits were killed 12 weeks later. Lumbar spinal magnetic resonance images were assessed using 4 grades of disc degeneration. The water content of the nucleus was measured. Dimethylmethylene blue (DMMB) assay was used to measure the sulfated-glycosaminoglycan content. Second experiment: the 21-gauge 3-puncture and the 18-gauge 1-puncture models, thought most effective in producing disc degeneration in the first experiment, were again used in a second study. Six rabbits were killed 8 weeks later, the water and sulfated-glycosaminoglycan contents being measured as in the first experiment.

RESULTS

In the first experiment, the water content in the aspiration and puncture models was significantly decreased. Only the sulfated-glycosaminoglycan content in the aspiration model showed a significant decrease as compared to the control. Disc heights and magnetic resonance grades documented significant degeneration occurring in the aspiration and puncture models. In the second experiment, the water content showed a significant decrease in the 21-gauge 3-puncture model, whereas neither of the results for the sulfated-glycosaminoglycancontent showed a significant difference as compared to the control data.

CONCLUSION

In the first experiment, the 21-gauge 3-puncture and the 18-gauge 1-puncture models produced the most consistent disc degeneration in the rabbit lumbar spine. When these 2 models were again studied in the second experiment, the 21-gauge 3-puncture technique was superior in producing disc degeneration over a shorter period of time.

Expression and distribution of tumor necrosis factor alpha in human lumbar intervertebral discs: a study in surgical specimen and autopsy controls

STUDY DESIGN

Immunohistochemical study of tumor necrosis factor alpha expression in autopsy and surgical specimens of human lumbar intervertebral discs.

OBJECTIVES

To investigate the occurrence and localization of tumor necrosis factor alpha in intervertebral disc tissue and to correlate its expression with age and the degree of disc degeneration.

SUMMARY OF BACKGROUND DATA

The source and origin of discogenic pain are as yet unknown. Recently identified changes of the cellular phenotype during senescence and disc pathology with partly phagocytic properties suggest an 'inflammatory' phenotype. Tumor necrosis factor alpha is one of the most potent proinflammatory cytokines possibly modulating cellular phenotypes. It may also promote pain induction. Very little is known about the occurrence and localization of tumor necrosis factor alpha in intervertebral disc tissue of defined age and degree of histologic tissue degeneration.

METHODS

The study population comprised 20 cross-sections of the complete motion segment of human lumbar vertebrae (age range 0-86 years) obtained at autopsy and 28 surgical disc specimens of individuals undergoing lumbar surgical interventions for various reasons. The temporospatial distribution of tumor necrosis factor alpha-positive cells using a polyclonal antibody was correlated with a histologic degeneration score.

RESULTS

Tumor necrosis factor alpha is expressed substantially in (nonsymptomatic) autopsy material in fetal/infantile and older adult nucleus pulposus, whereas it is sparsely expressed in adolescent and young adult nucleus pulposus. In the anulus fibrosus, tumor necrosis factor alpha is not found in young adults (<25 years), but then significantly increases in extent. In contrast, symptomatic nucleus pulposus and anulus fibrosus (surgical material) contain substantially more tumor necrosis factor alpha-positive cells. A significant positive correlation of tumor necrosis factor alpha expression and disc degeneration (histologic degeneration score) was found for the anulus fibrosus in both sample groups. In the surgical material, an additional significant positive correlation was identified for nuclear tumor necrosis factor alpha, disc degeneration, and age.

CONCLUSIONS

Tumor necrosis factor alpha is substantially expressed in disc material of symptomatic patients (surgical specimens) in comparison to samples taken at autopsy. The expression of tumor necrosis factor alpha in early fetal/infantile nucleus pulposus may indicate 'physiologic' tissue disarrangement with closure of the blood vessel canals. The expression of tumor necrosis factor alpha in adult discs, in contrast, is statistically associated with disc degeneration. Its occurrence in adults of more advanced age suggests that tumor necrosis factor alpha is not involved in the initiation of disc degeneration, but may be associated with further promotion of degenerative disarrangement and pain induction.

ISSLS prize winner: A study of diffusion in human lumbar discs: a serial magnetic resonance imaging study documenting the influence of the endplate on diffusion in normal and degenerate discs

STUDY DESIGN

An in vivo serial magnetic resonance imaging study of diffusion characteristics in human lumbar discs over 24 hours in healthy volunteers and patients with low back pain.

OBJECTIVES

To document the temporal pattern of diffusion in normal human lumbar discs and to study the influence of the vascularity of bone and the status of endplate on diffusion in the normal and degenerate discs.

SUMMARY OF BACKGROUND DATA

Diffusion is the only source of nutrition to the discs, but no firm data are available on pattern of diffusion in humans. More data on this important subject are required to improve our understanding of disc degeneration and to probe research possibilities for preventing the same.

METHODS

The diffusion pattern over 24 hours following gadodiamide injection was studied in 150 discs (96 normal and 54 degenerate). Signal intensity values for three regions of interest in bone (i.e., vertebral body, subchondral bone, and endplate zone) and seven in the disc were calculated, and normal percentiles of diffusion were derived for these regions. Enhancement percentage for each time period, peak enhancement percentage for each region, and the time taken to achieve peak enhancement percentage (Tmax) were used to define and compare diffusion characteristics and plot a time-intensity curve to document the 24-hour temporal pattern. The correlation of blood flow of the bone as measured by peak enhancement percentage of vertebral body, the status of the endplate zone as measured by the peak enhancement percentage, and Tmax of the endplate zone were correlated with the diffusion of the disc.Univariate analysis of variance, multiple comparisons, appropriate tests for significance, and stepwise linear regression analysis were used for analysis of the data using SPSS software.

RESULTS

In normal discs, a "diffusion march" from the vertebral body to the center of disc was noted with the SImax being observed at 5 min in the vertebral body and subchondral bone, at 2 hours in the endplate zone, and at 6 hours in the nucleus pulposus. A significant difference in mean peak enhancement percentage was observed between that of the body and the discs in those less than 10 years and those above the age of 20 years (P < 0.001). Alterations in endplate zone produced distinct magnetic resonance imaging signs of disturbance in diffusion, which offered a reliable noninvasive method of identifying endplate cartilage damage. Stepwise linear regression analysis showed that the significant variable influencing diffusion to the center of the nucleus pulposus of the total sample was peak enhancement percentage of endplate zone (R2 = 0.216; P < 0.001), that of degenerate discs was peak enhancement percentage of endplate zone (R2 = 0.322; P < 0.001), and that of normal discs (R2 = 0.324; P < 0.001) was age.

CONCLUSIONS

Serial postcontrast magnetic resonance imaging studies offer a reliable method of assessing the diffusion of the discs and the functional status of the endplate cartilage. Endplate cartilage damage increases with age and produces considerable changes in diffusion. The present study has described reliable signs by which these damages can be identified in vivo. Aging and degeneration have been shown to be two separate processes by documenting clear-cut differences in diffusion. The present data encourage use of diffusion studies as a noninvasive method to assess the physiologic status of the disc and endplate and to study the effect of drugs, smoking, mechanical loading, exercises, etc. on the physiology of the disc.

MR aortography and serum cholesterol levels in patients with long-term nonspecific lower back pain

STUDY DESIGN

A cross-sectional analysis of the feeding arteries of the lumbar spine and cholesterol levels on patients with long-term nonspecific lower back pain.

OBJECTIVES

To evaluate whether occlusion of lumbar and middle sacral arteries or serum cholesterol levels are associated with lower back pain and/or with disc degeneration.

SUMMARY OF BACKGROUND DATA

Atherosclerosis in the wall of the abdominal aorta usually develops at the ostia of branching arteries and the bifurcation, and may obliterate orifices of lumbar and middle sacral arteries. Obstruction of these arteries causes ischemia in the lumbar spine and may result in back symptoms and disc degeneration.

METHODS

MR aortography and cholesterol blood tests were performed on 51 patients with long-term lower back pain without specific findings (i.e., spinal or nerve root compression) in regular lumbar MR images. The patients ranged from 35 to 70 years of age (mean age, 56 years). Serum cholesterol and low-density lipoprotein (LDL) cholesterol levels were measured. To assess symptoms and disability NASS low back Outcome Instrument was used.

RESULTS

Twenty-nine (78%) of 37 men and 11 (77%) of 14 women showed occluded lumbar and/or middle sacral arteries. The prevalence of occluded arteries was 2.5 times more than in subjects of corresponding age group in a Finnish necropsy material. Twenty-three (62%) men and seven (50%) women had significant disc degeneration. Disc degeneration was associated with occluded lumbar/middle sacral arteries (P = 0.035). Patients with occluded arteries or significant disc degeneration did not complain more severe symptoms than those without, whereas patients with above normal serum LDL cholesterol scored higher in neurogenic symptoms (P = 0.031) and complained more often severe pain (P = 0.049) than those with normal LDL cholesterol.

CONCLUSIONS

The study indicates that lumbar and middle sacral arteries are often occluded in patients with nonspecific long-term lower back pain. Occlusion of these arteries may also be associated with disc degeneration.

Risk factors for adjacent segment degeneration after PLIF

STUDY DESIGN

A retrospective study of 87 patients who underwent posterior lumbar interbody fusion (PLIF) at L4-L5 for L4 degenerative spondylolisthesis.

OBJECTIVE

To clarify: 1) the correlation between radiologic degeneration of cranial adjacent segment and clinical results, 2) risk factors for radiologic degeneration of cranial adjacent segment, and 3) preoperative radiologic features of patients who underwent additional surgery with cranial adjacent segment degeneration.

SUMMARY OF BACKGROUND DATA

Whereas PLIF with pedicle screw fixation has shown satisfactory clinical results, a solid fusion has been reported to accelerate a degenerative change at unfused adjacent levels, especially in the cranial level. Although several authors have reported the adjacent segment degeneration after PLIF, there are no previous reports of risk factors for adjacent segment degeneration after PLIF.

MATERIALS AND METHODS

Eighty-seven patients who underwent PLIF for L4 degenerative spondylolisthesis and could be followed for at least 2 years were included in this study. We measured lumbar lordosis, scoliosis, laminar inclination angle at L3, facet sagittalization at L3-L4, facet tropism at L3-L4, preexisting disc degeneration at L3-L4, and lordosis at the fused segment. Progression of L3-L4 segment degeneration was defined as a condition in which disc narrowing, posterior opening, and progress of slippage in comparison with preoperative dynamic lateral radiographs. Patients were divided into three groups according to postoperative progression of L3-L4 degeneration: Group 1 with neither progression of L3-L4 degeneration nor neurologic deterioration, Group 2 with progression of L3-L4 degeneration but no neurologic deterioration, and Group 3 with an additional surgery required for neurologic deterioration. Correlation between clinical results and radiologic progression of L3-L4 degeneration, and risk factors for progression of radiologic degeneration were investigated. Further, preoperative radiologic features of Group 3 were studied to detect risk factors for clinical deterioration.

RESULTS

There were 58 (67%) patients classified into Group 1, 25 (29%) patients into Group 2, and 4 (4%) patients into Group 3. There was no significant difference in average age in each group. No obvious difference was observed in recovery rate between Groups 1 and 2. Laminar inclination angle and facet tropism in Group 3 were more significant than those in Groups 1 and 2. Further, apparent lamina inclination and facet tropism coexisted in Group 3. There were no obvious differences in other factors between each group.

CONCLUSION

1) There was no correlation between radiologic degeneration of cranial adjacent segment and clinical results. 2) Risk factors for postoperative radiologic degeneration could not be detected in terms of each preoperative radiologic factor. 3) Coexistence of horizontalization of the lamina at L3 and facet tropism at L3-L4 may be one of the risk factors for neurologic deterioration resulting from accelerated L3-L4 degenerative change after L4-L5 PLIF.

Synovial cysts of the lumbar facet joints in a symptomatic population: prevalence on magnetic resonance imaging

STUDY DESIGN

A retrospective review of 303 MRI scans of the lumbar spine was conducted.

OBJECTIVES

To determine the prevalence of lumbar facet joint synovial cysts arising from the joints anteriorly and posteriorly. To examine the association of these cysts with facet joint osteoarthritis and degenerative disc disease.

SUMMARY OF BACKGROUND DATA

Sporadic reports of such cysts exist as do limited studies describing the prevalence of symptomatic anterior facet joint synovial cysts. However, the overall prevalence of lumbar facet joint synovial cysts has not been formally studied, and the mechanism of formation of these cysts is not fully understood.

METHODS

One observer undertook a review of MRI of the lumbar spine from one facility in a series of 303 patients referred mostly for back pain or radiculopathy. The presence of lumbar facet joint synovial cysts, their relationship to the facet joint, the degree of associated facet joint osteoarthritis, the presence of spondylolisthesis, and the degree of associated disc degeneration were recorded.

RESULTS

Seven anterior cysts (prevalence = 2.3%) were identified, only two of which did not clearly cause nerve root compression. Twenty-three posterior cysts in 22 patients (prevalence = 7.3%) were identified. Statistically significant associations with increased frequency and severity of facet joint osteoarthritis and with spondylolisthesis were demonstrated compared to patients without cysts.

CONCLUSIONS

Both anterior and posterior lumbar facet joint synovial cysts are rare. Posterior cysts are more common than anterior cysts. Both types of cysts are related to facet joint osteoarthritis but not to disc disease.

MR Image–based Grading of Lumbar Nerve Root Compromise due to Disk Herniation: Reliability Study with Surgical Correlation

A system for grading lumbar nerve root compromise (no compromise, contact of disk material with nerve root, deviation of nerve root, and compression of nerve root) was tested in the interpretation of routine magnetic resonance images of 500 lumbar nerve roots in 250 symptomatic patients. Intra- and interobserver reliability was assessed for three independent observers. In the 94 nerve roots evaluated at surgery, surgical grading was correlated with image-based grading. kappa statistics indicated substantial agreement between different readings by the same observer and between different observers (for intraobserver agreement, kappa = 0.72-0.77; for interobserver agreement, kappa = 0.62-0.67). Correlation of image-based grading with surgical grading was high (r = 0.86). The image-based grading system enabled reliable evaluation and reporting of nerve root compromise.

Classification of age-related changes in lumbar intervertebral discs: 2002 Volvo Award in basic science

STUDY DESIGN

A histologic study on age-related changes of the human lumbar intervertebral disc was conducted.

OBJECTIVES

To investigate comprehensively age-related temporospatial histologic changes in human lumbar intervertebral disc, and to develop a practicable and reliable classification system for age-related histologic disc alteration.

SUMMARY OF THE BACKGROUND DATA

No comprehensive microscopic analysis of age-related disc changes is available. There is no conceptual morphologic framework for classifying age-related disc changes as a reference basis for more sophisticated molecular biologic analyses of the causative factors of disc aging or premature aging (degeneration).

METHODS

A total of 180 complete sagittal lumbar motion segment slices obtained from 44 deceased individuals (fetal to 88 years of age) were analyzed with regard to 11 histologic variables for the intervertebral disc and endplate, respectively. In addition, 30 surgical specimens (3 regions each) were investigated with regard to five histologic variables. Based on the semiquantitative analyses of 20,250 histologic variable assessments, a classification system was developed and tested in terms of validity, practicability, and reliability. The classification system was applied to cadaveric and surgical disc specimens not included in the development of the classification system, and the scores were assessed by two additional independent raters.

RESULTS

A semiquantitative analyses provided clear histologic evidence for the detrimental effect of a diminished blood supply on the endplate, resulting in the tissue breakdown beginning in the nucleus pulposus and starting in the second life decade. Significant temporospatial variations in the presence and abundance of histologic disc alterations were observed across levels, regions, macroscopic degeneration grades, and age groups. A practicable classification system for age-related histologic disc alterations was developed, resulting in moderate to excellent reliability (kappa values, 0.49-0.98) depending on the histologic variable. Application of the classification system to cadaveric and surgical specimens demonstrated a significant correlation with age ( < 0.0001) and macroscopic grade of degeneration ( < 0001). However, substantial data scatter caution against reliance on traditional macroscopic disc grading and favor a histology-based classification system as a reference standard.

CONCLUSIONS

Histologic disc alterations can reliably be graded based on the proposed classification system providing a morphologic framework for more sophisticated molecular biologic analyses of factors leading to age-related disc changes. Diminished blood supply to the intervertebral disc in the first half of the second life decade appears to initiate tissue breakdown.

Black disc disease: a commentary

Internal disc disruption associated with axial back pain but not radicular pain is a disease entity that was recognized about two decades ago as a disorder that could potentially be treated by spinal fusion. In this article the authors describe the clinical syndrome, magnetic resonance imaging and discography findings of pathophysiological pain generation, and the available surgical options. Based on the current understanding of this disease entity, the optimum surgical procedure entails radical discectomy, anterior column support, adequate amounts of auto- or allograft bone, bone extenders and enhancers, and rigid stabilization of the motion segment.

Risk factors for lumbar disc degeneration: a 5-year prospective MRI study in asymptomatic individuals

STUDY DESIGN

A longitudinal magnetic resonance imaging investigation of lumbar disc degeneration in asymptomatic individuals was conducted.

OBJECTIVE

To investigate risk factors for the development or deterioration of lumbar disc degeneration.

SUMMARY OF BACKGROUND DATA

Numerous studies have explored the significance of certain risk factors for the development or progression of disc degeneration, but no comprehensive longitudinal magnetic resonance imaging-based study has been reported that simultaneously considers clinical, morphologic, physical, psychosocial, and occupational risk factors.

METHODS

In the 5-year follow-up evaluation of 41 asymptomatic individuals, the risk factors for the development of lumbar disc degeneration and its progression were investigated. All 41 individuals had a magnetic resonance imaging scan at baseline and at the minimum 5-year follow-up assessment using the same scanner and protocol. The magnetic resonance images were analyzed independently by two radiologists with regard to disc degeneration. Various predictor variables were assessed both at baseline and follow-up, with special emphasis on physical job characteristics, sports activities, and magnetic resonance image-based morphologic findings.

RESULTS

Of the 41 individuals, 17 (41%) exhibited a deterioration of the disc status. In 10 individuals, the progression of disc degeneration was one grade or more. Only a weak correlation existed between progressive disc degeneration and low back pain development during a 5-year follow-up period. Multiple logistic regression analysis demonstrated that the extent of disc herniation (odds ratio [OR], 12.63; confidence interval [CI], 1.24-128.49), the lack of sports activities (OR, 2.71; CI, 1.04-7.07), and night shift work (OR, 23.01; CI, 1.26-421.31) were significant predictors for disc degeneration during follow-up evaluation when control was used for the number of degenerated discs at baseline, gender, age, and body mass index.

CONCLUSIONS

The results indicate that the extent of disc herniation, the lack of sports activities, and night shift work are significant risk factors for the development of lumbar disc degeneration and its progression.