Magnetic resonance imaging in the diagnosis of disc degeneration: correlation with discography

Interleukin 1 Polymorphisms and Intervertebral Disc Degeneration

BACKGROUND

Enzymatic breakdown of the extracellular matrix, and possibly local inflammation, contributes to intervertebral disc degeneration. We investigated whether polymorphisms within the IL-1 gene locus are associated with lumbar disc degeneration and whether the effect of occupational physical load on disc degeneration is modified by the polymorphisms.

METHODS

Genotypes were determined from 133 middle-aged men who underwent magnetic resonance imaging of the lumbar spine. The participants represented 3 occupations: 40 were machine drivers, 42 carpenters, and 51 office workers. We evaluated decreased signal intensity of the nucleus pulposus, disc bulges, and decreased disc height as signs of degeneration in the L2/L3-L5/S1 discs.

RESULTS

The odds ratio for disc bulges was 2.4 (95% confidence interval = 1.2-4.8) and 1.9 (1.0-3.7), in carriers of the IL-1alphaT or IL-1betaT alleles, respectively. The TT genotype of the IL-1alpha gene carried more than 3-fold risk of disc bulges as compared with the CC genotype.

CONCLUSIONS

IL-1 gene cluster polymorphisms could affect the risk of disc degeneration. The effect of physical workload seems to be modified by the IL-1 gene polymorphisms.

Radiofrequency lesioning using two different time modalities for the treatment of lumbar discogenic pain: a randomized trial

STUDY DESIGN

A prospective randomized trial.

OBJECTIVE

To evaluate the efficacy of percutaneous intradiscal radiofrequency thermocoagulation by modifying the duration of heating, using two different time methods, for relieving pain and improving functional disability.

SUMMARY OF BACKGROUND DATA

Lumbar discogenic pain is the major problem in lumbar degenerative disc disease that percutaneous intradiscal radiofrequency thermocoagulation has been suggested for as a nonsurgical invasive treatment technique for lumbar discogenic pain. In a previous controlled study, this method was found to be ineffective with 8 weeks of follow-up.

MATERIALS AND METHODS

Sixty patients with chronic low back pain were selected for provocative discography to diagnose the discogenic pain and to locate the discs to be treated. From this group, 39 patients were randomly selected and divided into two groups. In the first group, treatment was performed for 120 seconds, and in the second group for 360 seconds, both at 80C. Patients were assessed with a visual analogue scale for pain relief and functional improvement. Evaluations were performed before, immediately after treatment, at 1 and 2 weeks, and at 1, 3, and 6 months after the procedure.

RESULTS

A total of 39 patients with positive provocative discographies were found to eligible for the study. There were no statistical differences in pain relief and functional improvement between two groups (P > 0.05). The immediate, 1-week and 2-week, and 1-month visual analogue scale (VAS) scores were decreased significantly in both groups when comparing them with the pretreatment scores (P < 0.05). However, the final values after 6 months were similar to those measured at the beginning of the study (P > 0.05).

CONCLUSION

Percutaneous intradiscal radiofrequency thermocoagulation has been suggested and performed to relieve discogenic pain. In the previous controlled study, no effective pain relief has been obtained. In this study, the authors increased the duration of radiofrequency thermocoagulation to improve the effectiveness of this method. Yet, the authors have not found any significant differences between the application of lesioning at two different times in percutaneous intradiscal radiofrequency thermocoagulation.

Intradiscal electrothermal therapy: a treatment option in patients with internal disc disruption

STUDY DESIGN

A literature review was conducted.

OBJECTIVES

To review the anatomy, pathophysiology, diagnosis, procedure, and clinical results of intradiscal electrothermal therapy (IDET).

SUMMARY OF BACKGROUND DATA

Low back pain is a major physical and socioeconomic entity. A significant percentage of low back pain is attributable to internal disc disruption. The management of internal disc disruption has traditionally been limited to either conservative treatment or spinal fusion. IDET has been performed as an alternative to these therapies.

METHODS

The available literature was reviewed.

RESULTS

Scientific data regarding the pathophysiology, biologic effects, and clinical results are relatively scarce. Early biomechanical and histologic investigations into the effects of IDET are conflicting. However, in early prospective human trials, IDET seems to provide some benefit with little risk.

CONCLUSIONS

IDET is potentially beneficial treatment for internal disc disruption in carefully selected patients as an alternative to spinal fusion. More basic science and clinical research with long-term follow-up evaluation is necessary.

Diskography outcomes in patients following lumbar diskectomy

The results of lumbar diskography at post-diskectomy and nonoperative disk levels in postoperative patients and patients without prior back surgery were reviewed over 3 years. Other possible predictive factors, including disk degeneration (per the Adam's classification), end-point resistance, gender, and age, also were reviewed. The results revealed that no statistically significant association was noted between the presence of a prior diskectomy and the outcome of diskography. However, disk degeneration classified as ruptured and fissured correlated statistically with positive diskography. Additionally, age between 30 and 39 years and male gender were statistically associated with a positive diskogram. Disk levels displaying a poor end point during diskography injection (not amendable to pressurization) were statistically related to ruptured or fissured disk levels and thus positive diskography. Based on these results, the assumption that disabling low-back pain presenting after lumbar procedure is due to diskogenic disease arising from the surgical level is not supported.

Chronic Chlamydia pneumoniae infection increases the risk of occlusion of lumbar segmental arteries of patients with sciatica: a 3-year follow-up study

STUDY DESIGN

A magnetic resonance imaging follow-up study of lumbar arteries among patients with sciatica with chronic Chlamydia pneumoniae infection.

OBJECTIVE

To determine whether chronic infection causes occlusion of lumbar arteries.

SUMMARY OF BACKGROUND DATA

C. pneumoniae infection is associated with coronary heart disease, and the infectious pathogen has also been detected in abdominal aortic aneurysms and in atherosclerotic plaques. No studies are available on the effect of this infectious agent on lumbar arteries.

METHODS

Chronic infection was defined as persistent high positive immunoglobulin G and/or immunoglobulin A antibodies and/or the presence of immune complexes. The lumbar arteries, evaluated with two-dimensional time-of-flight magnetic resonance angiography, were scored as normal, narrowed, or occluded. The differences in the segmental and whole lumbar spine (segments L1-L4) sum of arterial occlusion at baseline and at 3 years, and the incidence of new arterial stenosis were compared in patients with and without chronic infection using the Kolmogorov-Smirnov test.

RESULTS

Patients with chronic infection were more likely to be persistent smokers (P = 0.006), male (P = 0.04), and more obese (P = 0.02) compared to patients with normal antibody levels. They had significantly higher degree of arterial stenosis at L4 segment at baseline and at 3 years (P = 0.001 and 0.002, respectively), in the whole lumbar spine at baseline and at 3 years (P < 0.001 for both), and at L1 and L3 segments at 3 years (P = 0.013 for both). The incidence of new arterial stenosis was similar in both patient groups. Patients with chronic infection also had significantly higher grade of endplate degeneration at L4-L5 (P = 0.008).

CONCLUSIONS

The results of this study suggest that chronic C. pneumoniae infection may induce stenosis of lumbar arteries.

A pilot study of the prevalence of lumbar disc degeneration in elite athletes with lower back pain at the Sydney 2000 Olympic Games

OBJECTIVES

To observe the prevalence of lumbar intervertebral disc degeneration in elite athletes as compared with published literature of changes seen in non-athletes-that is, normal population.

METHODS

The lumbar spines of 31 Olympic athletes who presented to the Olympic Polyclinic with low back pain and/or sciatica were examined using magnetic resonance imaging. Three criteria were looked at: (a) the loss of disc signal intensity; (b) the loss of disc height; (c) the presence of disc displacement. The results were then recorded and correlated with the lumbar levels.

RESULTS

The disc signal intensity was progressively reduced the more caudal the disc space. It was most common at the L5/S1 level, and, of the abnormal group, 36% (n = 11) showed the most degenerative change. Disc height reduction was also found to be most common at the L5/S1 level. However, the most common height reduction was only mild. A similar trend of increased prevalence of disc herniation was noted with more caudal levels. At the L5/S1 level, 58% were found to have an element of disc displacement, most of which were disc bulges. Compared with changes seen in the normal population (non-athletes) as described in the literature, disc degeneration defined by the above criteria was found to be significantly more severe in these Olympic athletes.

CONCLUSIONS

Although the study was limited, the results suggest that elite athletes have a greater prevalence and greater degree of lumbar disc degeneration than the normal population. A more detailed follow up study should be considered to investigate which particular training activities have the most impact on the lumbar spine, and how to modify training methods so as to avoid the long term sequelae of degenerative disc disease of the lumbar spine.

Lumbar discography

STUDY DESIGN

A comprehensive review of the literature dealing with lumbar discography was conducted.

OBJECTIVE

The purpose of the review is to update the North American Spine Society position statement published in 1994 that addressed criticisms of lumbar discography, to identify indications for

SUMMARY OF BACKGROUND DATA

Lumbar discography remains a controversial diagnostic procedure. There are concerns about its safety and clinical value, although many support its use in specific applications.

METHODS

Articles dealing with lumbar discography were reviewed and are summarized in this report.

RESULTS

Most of the recent literature supports the use of discography in selected patients. Although not to be taken lightly, many of the serious complications and high complication rates reported before 1970 have decreased since then because of improvement in injection technique, imaging and contrast materials.

CONCLUSIONS

Most of the current literature supports the use of discography in select situations. Indications for discography include, but are not limited to: (1) Further evaluation of demonstrably abnormal discs to help assess the extent of abnormality or correlation of the abnormality with the clinical symptoms. Such symptoms may include recurrent pain from a previously operated disc and lateral disc herniation. (2) Patients with persistent, severe symptoms in whom other diagnostic tests have failed to reveal clear confirmation of a suspected disc as the source of pain. (3) Assessment of patients who have failed to respond to surgical intervention to determine if there is painful pseudarthrosis or a symptomatic disc in a posteriorly fused segment and to help evaluate possible recurrent disc herniation. (4) Assessment of discs before fusion to determine if the discs within the proposed fusion segment are symptomatic and to determine if discs adjacent to this segment are normal. (5) Assessment of candidates for minimally invasive surgical intervention to confirm a contained disc herniation or to investigate dye distribution pattern before chemonucleolysis or percutaneous procedures. Lumbar discography should be performed by those well experienced with the procedure and in sterile conditions with a double-needle technique and fluoroscopic imaging for proper needle placement. Information assessed and recorded should include the volume of contrast injected, pain response, with particular emphasis on its locations and similarity to clinical symptoms, and the pattern of dye distribution. Frequently, discography is followed by axial computed tomography scanning to obtain more information about the condition of the disc.

Indications, techniques, and outcomes of posterior surgery for chronic low back pain

This article summarizes a number of issues surrounding the diagnosis, indications, and techniques of posterior lumbar spine surgery for chronic low back pain. It would not be entirely unjustified for a spine surgeon to adhere to a totally avoidant approach to chronic low back pain, rationalized by a reasonably legitimate nihilism regarding the presently available means of diagnosing and surgically managing low back pain [64]. Judging by the number of lumbar fusions performed in North America and the tremendous intellectual and financial investment currently being made in technologies to enhance spinal fusion, such an approach is evidently not achieving wide-spread acceptance on this continent. A rationale approach is therefore required for the many low back pain sufferers with degenerative disk disease who arrive in the office having exhausted almost every imaginable form of nonoperative therapy. Every effort should be made to establish a pathoanatomic etiology of the back pain with a combination of diagnostic modalities. Surgical intervention should be approached cautiously and only after extensive dialog with the patient to establish realistic goals and expectations. Posteriorly performed interbody fusion procedures may provide a high fusion rate and satisfactory clinical outcomes for this challenging problem, although further research is necessary to determine more conclusively the role of surgery and the relative effectiveness of the various arthrodesis techniques.

The role of repeated end-range/pain response assessment in the management of symptomatic lumbar discs

BACKGROUND CONTEXT

The selection of appropriate patients for lumbar disc surgery is a challenging task involving a highly variable, multifactorial decision process complicated by a lack of reliable, validated clinical signs and imaging findings. Recently, multiple studies have demonstrated the reliability and diagnostic utility of a standardized form of spinal assessment using repeated end-range test movements while monitoring patterns of pain response (McKenzie assessment).

PURPOSE

It is the aim of this article to evaluate the utility of this assessment system and its literature support in the selection of candidates for surgery for disc-related pain.

STUDY DESIGN AND METHODS

A literature review.

RESULTS

Most patients under consideration for lumbar disc surgery, when examined using this form of dynamic mechanical spinal evaluation, based on patients' patterns of pain response to standardized repeated end-range lumbar test movements and positions, fall into one of three subgroups: 1) a reversible condition, 2) an irreversible condition or 3) an unaffected condition. Reversible conditions in acute to chronic low back and/or leg pain are recoverable, often rapidly so, using nonoperative self-care dictated by the patient's assessment findings. The elicitation of pain "centralization," an improvement (favorable change) in pain location in response to repetitive end-range testing, typically occurring with only one direction of test movement(s), predicts a high likelihood of successful response to conservative care, even in the presence of neurologic deficits. Irreversible conditions are characterized by symptom aggravation by all directions of testing, including the absence of the centralization response, predicting a poor response to nonsurgical care. In those whose pain is unaffected with similar testing, evidence indicates the pain is likely nondiscogenic. A dynamic disc model has been described as a possible model for these varying pain responses. Insight into annular integrity of symptomatic discs is also provided using this repeated end-range/pain response (McKenzie) assessment.

CONCLUSIONS

As described, the literature supports the use of a repeated end-range/pain response assessment (dynamic mechanical evaluation) in obtaining diagnostic and therapeutic information in patients with low back and leg pain. This may contribute to improving the selection process of surgical patients.

The association of lumbar disc disease with vitamin-D receptor gene polymorphism

BACKGROUND

Although the etiology of lumbar disc disease is unknown, it has been suggested that a genetic factor contributes to its development. Recently, some genetic polymorphisms have been found to be related to clinical disorders. We investigated the association between vitamin-D receptor gene and estrogen receptor gene polymorphisms and lumbar disc disease in young adults.

METHODS

The participants included 205 young adults (166 women and thirty-nine men) with or without low-back problems. A magnetic resonance imaging scan of the lumbar spine was performed for all subjects, and the grade of disc degeneration was determined, according to the four-grade classification system of Schneiderman et al. The presence or absence of disc herniation was also evaluated. Genomic DNA was extracted from peripheral blood samples. The polymorphisms of the vitamin-D receptor and estrogen receptor genes were detected with use of a polymerase-chain-reaction assay. The restriction fragment length polymorphisms (RFLPs) for the vitamin-D receptor gene were analyzed by TaqI and ApaI restriction enzymes. XbaI and PvuII restriction enzymes were used for the estrogen receptor gene analysis. The distribution of polymorphism in subjects with disc degeneration and/or disc herniation was compared with that in the normal subjects.

RESULTS

The allelic frequencies of both vitamin-D receptor gene and estrogen receptor gene polymorphisms were similar to those in previous analyses of Japanese subjects. The allelic variation in the vitamin-D receptor gene was associated with multilevel and severe disc degeneration and disc herniation. The Tt allele was found to be more frequently associated with multilevel disc disease, severe disc degeneration, and disc herniation than was the TT allele. No additional associations were found.

CONCLUSIONS

This study revealed that the Tt allele of the vitamin-D receptor gene was more frequently associated with multilevel and severe disc degeneration and disc herniation than was the TT allele, pointing to an increased risk of disc disease at an early age in subjects with the Tt allele in the vitamin-D receptor gene.

Endplate degeneration observed on magnetic resonance imaging of the lumbar spine: correlation with pain provocation and disc changes observed on computed tomography diskography

STUDY DESIGN

One hundred and three lumbar intervertebral discs (L3/4-L5/S1) of 36 patients with low back pain were examined with computed tomography (CT) diskography and magnetic resonance imaging (MRI).

OBJECTIVES

To determine whether lumbar endplate degeneration correlates with the degree of disc degeneration or disc rupture and to determine if there is an association between pain provocation during diskography and lumbar endplate degeneration.

SUMMARY OF BACKGROUND DATA

There have been numerous attempts to explain the pathogenesis of pain provocation during diskography, but the possibility of endplate degeneration as a source of pain has not been widely assessed.

METHODS

One hundred and three lumbar intervertebral discs (36 L3/4, 36 L4/5, and 31 L5/S1 intervertebral discs) of 36 patients were examined. On the basis of MRI, the intervertebral discs were divided into four categories based on the degree of endplate degeneration. Based on pain provocation on diskography, the intervertebral discs were divided into three categories: no pain, indifferent/untypical pain, and familiar/typical pain. Based on disc degeneration and disc rupture, the intervertebral discs were divided into four categories in accordance with the Dallas Discogram Description: Grades 0-3 of both degeneration and rupture.

RESULTS

There was a positive correlation between endplate degeneration and disc degeneration and a positive correlation between disc rupture and pain provocation, but there was no association between endplate degeneration and disc rupture and no correlation between endplate degeneration and pain provocation on diskography.

CONCLUSIONS

This study showed a stronger association between endplate degeneration and disc degeneration than between endplate degeneration and disc rupture. The results indicate that the contrast injection during diskography reflects mainly pain of discogenic origin, whereas the possible pain associated with endplate damage cannot be depicted by CT diskography.

Discography interpretation and techniques in the lumbar spine

The authors provide an indepth analysis of discography, a provocative diagnostic tool to determine the origin of low-back pain. Injecting the intervertebral disc with radiopaque dye provides physicians with several useful pieces of information. First, the modality provides radiographic evaluation of the integrity of the nucleus pulposus and annular rings to determine tears or other lesions that could be creating low-back pain. Second, and very important, is its measure of disc nociception. A normal disc should not cause pain when injected; however, a disc that is physiologically compromised can mimic the pain previously experienced by a patient. The authors review the indications, technique, and interpretation of discography to allow a better understanding of when to use this diagnostic test and what to do with the results.

Guidelines for the use of discography for the diagnosis of painful degenerative lumbar disc disease

OBJECT

Discography has been used as a diagnostic test in the evaluation of patients with recalcitrant low-back pain. Recently, its usefulness has been questioned because of the occurrence of false-positive results as well as the influence of psychological factors on test results. The purpose of this review is to establish the literature support for and against the use of discography. A search of the English-language literature published between 1966 and 2001 was performed. Papers were selected based on inclusion criteria described in the text, and the quality of information was graded using previously described methods.

CONCLUSIONS

The authors propose a set of practice parameters based on the literature. Although the data were not judged adequate for the determination of a treatment standard, parameters for the use of discography are provided at a guideline and option level.

Diagnosis of symptomatic disc by magnetic resonance imaging: T2-weighted and gadolinium-DTPA-enhanced T1-weighted magnetic resonance imaging

Although radial tear of the annulus fibrosus can be detected on T2-weighted and Gd-DTPA-enhanced magnetic resonance (MR) images, the association between the annular tear on MR images and the symptomatic discs is unclear. The purpose of this study was to investigate the relationship between T2-weighted, gadolinium-DTPA-enhanced MR images and pain response through discography in patients with chronic low back pain. A total of 56 lumbar discs from 23 patients with chronic low back pain (13 to 47 years old) underwent MR imaging (T2-weighted, gadolinium-DTPA-enhanced MR images) followed by provocative discography. The sensitivity, specificity, positive predictive value, and negative predictive value of T2-weighted and gadolinium-DTPA-enhanced MR images in detecting the symptomatic discs were calculated. The sensitivity, specificity, positive predictive value, and negative predictive value of T2-weighted images in detecting the symptomatic disc were 94%, 71%, 59%, and 97%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of gadolinium-DTPA-enhanced images were 71%, 75%, 56%, and 86%, respectively. The high sensitivity and the high negative predictive value of T2-weighted MR imaging in detecting the symptomatic disc indicated that MR imaging can be a useful screening tool in avoiding unnecessary discography in patients with chronic low back pain.

Does provocative discography screening of discogenic back pain improve surgical outcome?

The value of preoperative provocative discography in the setting of discogenic low back pain was investigated by evaluating surgical outcomes. Seventy-three consecutive patients who underwent posterolateral interbody and posterior spinal arthrodesis for discogenic low back pain refractory to nonoperative management were reviewed. Chronologically, the first 41 patients (group A) were indicated without discography, whereas the remaining 32 (group B) had been indicated only if their pain had been reproduced during disc injection. The two groups were similar in demographic, psychometric, and radiologic parameters. Average follow-up time in group A was 2.8 years and in group B it was 2.4 years, both with a 2-year minimum. Using modified Oswestry scoring, group A and group B patients had satisfactory outcomes of 75.6% and 81.2%, respectively. This difference was neither statistically significant nor suggestive. In this study, provocative discography screening did not improve surgical outcomes after circumferential fusion for lumbar discogenic back pain.

Chronic lumbar spine and radicular pain: pathophysiology and treatment

The lumbar spine forms the foundation and infrastructure of an organic skyscraper equipped with the physiologic capacity to act as a crane for lifting and a crankshaft for walking. Subjected to aging like other "human machinery," the lumbar spine adapts to the wear and tear of gravity and biomechanical loading through structural and neurochemical changes. Many of the changes are maladaptive, resulting in pain, physical and functional disability, and altered neurophysiologic circuitry. Some compensatory reactions are constructive, but others cause more interference with the organism's capacity to cope. A conceptional understanding of the multifaceted structural, biomechanical, biochemical, medical, and psychosocial influences that compose this mix elucidates the complexity of applying effective treatments.

Correlation of diffusion in lumbar intervertebral disks with occlusion of lumbar arteries: a study in adult volunteers

PURPOSE

To evaluate the correlation of the diffusion values in lumbar intervertebral disks with lumbar artery status and the degree of disk degeneration.

MATERIALS AND METHODS

Sagittal T2-weighted images of the lumbar spine were obtained in 37 asymptomatic volunteers aged 22-68 years. The apparent diffusion coefficient (ADC) of 98 lumbar intervertebral disks was determined, and two-dimensional time-of-flight magnetic resonance angiography was performed on the corresponding 98 lumbar artery pairs (total arteries = 196). The degree of disk degeneration and the status of lumbar arteries were evaluated independently by two radiologists. ADC calculations were performed on the basis of the average signal intensities of the selected region of interest in lumbar disks. The association between ADC values of disks, the disk degeneration, and the status of lumbar arteries of the same level were analyzed with analysis of covariance, and pairwise analysis between groups (Scheffé post hoc multiple comparison) was performed with statistical software. P values less than .01 were considered significant.

RESULTS

The lumbar arterial status correlated strongly with the diffusion values of intervertebral disks, and the ADC values decreased with higher degrees of arterial narrowing. The correlation between disk degeneration and diffusion was not significant. Eight severely degenerated disks with normal lumbar artery status and diffusion values were found.

CONCLUSION

Impaired flow in lumbar arteries is significantly associated with decreased diffusion in lumbar disks and may play an important role in disk degeneration.

Disc degeneration: a human cadaveric study correlating magnetic resonance imaging and quantitative discomanometry

STUDY DESIGN

This human cadaveric study evaluated disc degeneration of the lumbar spine using magnetic resonance imaging and quantitative discomanometry.

OBJECTIVE

To determine if a correlation exists between magnetic resonance imaging and quantitative discomanometry in determining disc degeneration of the lumbar spine.

SUMMARY OF BACKGROUND DATA

Several studies analyzing disc degeneration of the lumbar spine have compared magnetic resonance imaging with discography and discomanometry. The reported results are conflicting. No studies exist that compare magnetic resonance imaging and quantitative discomanometry in assessing the disc degeneration of the lumbar spine.

METHODS

Three fresh human cadaveric thoracolumbar spine specimens (two T11-S1 and one L1-S1) that included a total of 19 discs were used. Spines were scanned with magnetic resonance imaging, and the scans were read by a neuroradiologist. Using the quantitative discomanometry technique, discs were injected with normal saline, and pressure-volume curves were collected and quantified with six parameters: intrinsic pressure, leakage pressure, initial slope, slope from 0.0 to 0.1 mL, maximum pressure, and volume at maximum pressure. Data analysis was performed using Spearman's Rank Correlation (Rho) statistic.

RESULTS

Based on the results from 19 discs, an overall good correlation between magnetic resonance imaging scores and the six quantitative discomanometry parameters was demonstrated. With exception of the volume at maximum pressure, correlation coefficients ranged between 0.61 to 0.78 with a P < 0.05.

CONCLUSIONS

Magnetic resonance imaging scores and quantitative discomanometry parameters correlated well in the assessment of disc degeneration of the lumbar spine. Quantitative discomanometry may be an important technique for evaluating early disc degeneration, especially tears of the anular fibers, which may be missed on magnetic resonance imaging.

Post-traumatic findings of the spine after earlier vertebral fracture in young patients: clinical and MRI study

STUDY DESIGN

A study comparing magnetic resonance imaging findings of degenerative changes in intervertebral discs in young patients with previous wedge-shaped compression fracture and age-matched and sex-matched control subjects.

OBJECTIVES

To find out the role of fractures in disc degeneration and to assess the clinical outcome of the patients.

SUMMARY OF BACKGROUND DATA

Several experimental studies have postulated that trauma is one of the major reasons for disc degeneration. Wedge compression fractures in vertebrae of children have been considered insignificant, but this has not been verified in the literature.

METHODS

Fourteen patients 8.8 to 20.8 years of age (mean, 15.5 years) with a history of wedge-shaped vertebral compression fracture at least 1 year previously (mean, 3.8 years) and asymptomatic healthy control subjects were studied by thoracolumbar spine magnetic resonance imaging. The patients also underwent a clinical examination.

RESULTS

Eight (57%) of the 14 patients had disc degeneration, and seven of them had it at the trauma level. Of these 7 subjects, 6 also had endplate damage at this level. The association between endplate damage and adjacent intervertebral disc degeneration was significant (P < 0.01). Only 2 of the patients were symptomatic. In the control group, only 1 subject had disc degeneration with endplate changes and disc herniation.

CONCLUSIONS

The patients had more disc degeneration than did those in the control group. Endplate injury was strongly associated with disc degeneration. No correlation between previous vertebral fracture and back pain was seen in this study.

Association between an aggrecan gene polymorphism and lumbar disc degeneration

STUDY DESIGN

A case-control study using magnetic resonance imaging findings and a polymerase chain reaction assay to investigate the association between aggrecan gene polymorphism and lumbar disc degeneration.

OBJECTIVE

To analyze whether the aggrecan gene polymorphism is related to lumbar disc disease in young women.

SUMMARY OF BACKGROUND DATA

It has been suggested that a genetic factor or familial predisposition contributes to the development of lumbar disc herniation. However, the precise genetic component related to disc disease remains unclear. Recently, a polymorphism has been identified in the region of the human aggrecan gene. The expressed variable numbers of tandem repeat polymorphism occur in the highly conserved repeat region.

METHODS

The participants were 64 young women with or without low back problems. Magnetic resonance imaging was used to evaluate the degeneration and herniation of the intervertebral disc. Genomic deoxyribonucleic acid was extracted from all participants. A polymerase chain reaction assay was carried out to detect the alleles of the aggrecan gene. The association of intervertebral disc degeneration and herniation with the distribution of the aggrecan gene alleles was analyzed.

RESULTS

Findings showed an overrepresentation of alleles with small numbers of repeats in subjects with multilevel disc degeneration, thus indicating a significant distribution difference. There also was a significant difference between the distribution of alleles and the severity of disc degeneration. No significant association was found between any of the alleles either in number or type of disc herniation.

CONCLUSIONS

The current study showed that multilevel and severe disc degeneration was present in the participants with shorter variable numbers of tandem repeat length of the aggrecan gene. This suggests that subjects with shorter variable numbers of tandem repeat length of the aggrecan gene have a risk of having multilevel disc degeneration develop at an early age.

MRI of the lumbar intervertebral disc

The lumbar spine is one of the commonest regions of the body imaged with MRI. Various pathological processes can involve the lumbar intervertebral disc, including degeneration, infection and trauma and these may present with a variety of signal intensity and morphological changes as depicted by MRI. The aim of this pictorial review is to illustrate these abnormalities and discuss their clinical relevance where appropriate.

Thoracic discography in healthy individuals. A controlled prospective study of magnetic resonance imaging and discography in asymptomatic and symptomatic individuals

STUDY DESIGN

A prospective case-control investigation.

OBJECTIVES

To determine the responses to thoracic discography of asymptomatic individuals.

SUMMARY OF BACKGROUND DATA

Literature regarding lumbar and cervical discography reveals that even morphologically abnormal discs often are not painful, whereas painful discs typically exhibit anular or endplate disruption.

METHODS

Ten adult lifelong asymptomatic volunteers, ages 23 to 45 years, underwent magnetic resonance imaging of the thoracic spine, followed by four-level discography. Provocative responses were graded on a scale of 0 (no sensation) to 10 (extreme pain or pressure), and filmed discs were graded using a modified Dallas scheme. Concomitantly, 10 nonlitigious adults (6 men and 4 women, ages 31 to 55 years) experiencing chronic thoracic pain were similarly studied as a control group.

RESULTS

The mean pain response in the asymptomatic volunteers was 2.4/10. Three discs were intensely painful (scores of 7/10, 8/10, 10/10), with all three exhibiting prominent endplate irregularities and anular tears typical of thoracolumbar Scheuermann's disease. On discography, 27 of 40 discs were abnormal, with endplate irregularities, anular tears, and/or herniations. Ten discs read as normal on magnetic resonance imaging showed anular pathology on discography. In the group with chronic thoracic pain, the average pain response was 6.3/10 (P < 0.05). Of the 48 discs studied, 24 were concordantly painful, with a pain response of 8.5/10 (P < 0.05); 17 had nonconcordant pain/pressure, with an average pain of 4.8/10 (P < 0.05); and 5 had no response. On magnetic resonance imaging 21 of the 48 discs appeared normal. However, on discography, only 10 were judged as normal.

CONCLUSIONS

On discography, thoracic discs with prominent Schmorl's nodes may be intensely painful, even in lifelong asymptomatic individuals, but the pain is unfamiliar or nonconcordant. Thoracic discography may-demonstrate disc pathology not seen on magnetic resonance imaging.

Use of lumbar extension, slump test, physical and neurological examination in the evaluation of patients with suspected herniated nucleus pulposus. A prospective clinical study

This prospective and consecutive study was designed to evaluate the validity of different clinical tests, e.g. lumbar extension in lying and slump test for patients with suspected herniated nucleus pulposus, in comparison with findings on computed tomography (CT) and/or magnetic resonance imaging (MRI) scan. There were 105 patients who were seen and examined by the senior author (for the sake of the study) at the Orthopaedic Physiotherapy Department, on an average of 5.5 days (range 0-21 days) before CT and/or MRI examination were carried out. There were 36 women and 69 men with an average age of 42.7 +/- 9.8 (range 19-64) years. According to the radiological findings on CT and/or MRI, the patients were divided into three groups: 52 patients with disc hernia, 41 patients with bulging discs and 12 patients without positive findings. The mean values with standard deviations of 25 variables of three diagnostic groups were studied. Multiple comparison adjustment according to Bonferroni showed significant differences for three variables that were of diagnostic value (lumbar range of motion for forward flexion, left side-bending in standing, and pain distribution during extension in standing). The agreement between clinical and radiological findings for type and level of diagnosis of disc herniation was accurate in 72 patients (69%). The diagnostic sensitivity for disc herniation was 82.6% and the specificity 54.7%.

Differentiating lumbar disc protrusions, disc bulges, and discs with normal contour but abnormal signal intensity. Magnetic resonance imaging with discographic correlations

STUDY DESIGN

Independent evaluation by two observers of 132 lumbar discs in 45 patients with chronic low back pain investigated by both magnetic resonance imaging and discography.

OBJECTIVES

To assess some of the fundamental differences between lumbar disc protrusions, disc bulges, and discs with normal contour but abnormal signal intensity on T2-weighted magnetic resonance images.

SUMMARY OF BACKGROUND DATA

Moderate interobserver agreement has been reported when the morphologic terms normal, bulge, protrusion, and extrusion are used. The validity of this nomenclature remains unknown.

METHODS

Discs were evaluated on magnetic resonance images for central and peripheral signal characteristics, height, contour, and nerve root compression. Discograms were classified according to degrees of disc degeneration, disruption, and pain reproduction.

RESULTS

Loss of intervertebral height or abnormal signal intensity on magnetic resonance imagery was significantly associated with disc disruptions extending into or beyond the outer anulus on discograms. All 23 protrusions (100%) and 12 of 15 disc bulges (80%) were associated with Stage 2 or 3 anular disruptions and, in most instances, similar or exact reproduction of pain during disc injection. There was no significant difference between disc protrusions, disc bulges, and discs with normal contour but abnormal signal, with respect to degree of disc degeneration, extent of disruptions, or presence of discogenic pain.

CONCLUSIONS

In patients with chronic low back pain, loss of disc height or abnormal signal intensity is highly predictive of symptomatic tears extending into or beyond the outer anulus. Disc bulges and disc protrusions do not represent discs with significantly different internal architecture, based on the findings of discography, and are no more suggestive of symptomatic tears than discs showing normal contour but decreased height or abnormal signal intensity.

The stiffness of lumbar spinal motion segments with a high-intensity zone in the anulus fibrosus

STUDY DESIGN

Biomechanical and anatomic study of human cadaveric spinal motion segments.

OBJECTIVES

To measure the stiffness of spinal motion segments by disc type and by load type (flexion, extension, axial rotation, or lateral bending). To compare stiffness in motion segments with and without a high-intensity zone or radial tear in the anulus fibrosus.

SUMMARY OF BACKGROUND DATA

The high-intensity zone, that is a linear zone of high-intensity on T2-weighted magnetic resonance images corresponding to a radial tear in the anulus fibrosus, is a marker for a painful disc at discography. The high-intensity zone is hypothetically associated with diminished stiffness of the motion segment.

METHODS

Human cadaveric lumbar spinal motion segments with normal disc morphology or a high-intensity zone of the anulus fibrosus were selected on the basis of magnetic resonance imaging. The motion segments were subjected to incremental flexion, extension, rotation, and lateral bending torques. Rotation was measured with a kinematic system. Torque-rotation curves and stiffness were calculated for each motion segment and for each torque. The motion segments were sectioned on a cryomicrotome to verify the disc morphology as normal or as that of a radial tear.

RESULTS

In four motion segments with normal discs, stiffness was greater in axial rotation (8.4 Nm/degree) than in lateral bending (2.3 Nm/degree), flexion (1.8 Nm/degree), or extension (2.6 Nm/degree). In 16 motion segments with a high-intensity zone, stiffness was 2.4 Nm/degree in axial rotation, and less severely reduced in lateral bending, flexion, and extension. Stiffness in motion segments with a high-intensity zone was significantly less with smaller than with larger axial rotation loads.

CONCLUSIONS

The presence of a high-intensity zone in the intervertebral disc is associated with reduced stiffness of motion segments. The reduction is greater in axial rotation than in other torques. The reduction is more in smaller than in larger axial torques.

Disc degeneration and cervical instability. Correlation of magnetic resonance imaging with radiography

STUDY DESIGN

An imaging study was designed to evaluate disc degeneration and segmental instability in the cervical spine.

OBJECTIVES

To compare the magnetic resonance imaging assessment of disc degeneration with the conventional plain radiographic evaluation of cervical segmental instability.

SUMMARY OF BACKGROUND DATA

No studies have been conducted to investigate the association of disc degeneration with cervical instability.

METHODS

Two hundred sixty consecutive patients with suspected cervical spine disorders were analyzed for horizontal and angular displacements on lateral flexion and extension radiographs and disc degeneration on T2-weighted magnetic resonance images of the cervical vertebrae.

RESULTS

In all intervertebral levels, the grade of disc degeneration increased significantly (P < 0.01) with age. Cervical instability was identified in 151 segments (14.5%) and correlated with Grade 1 and Grade 2 degeneration in the intervertebral discs (P < 0.01).

CONCLUSIONS

Cervical segmental instability may indicate early degeneration of intervertebral disc in the cervical vertebrae.

A review of imaging techniques for canine cauda equina syndrome

There are many imaging modalities available for evaluating the canine lumbosacral region. These include conventional radiography, stress radiography, myelography, epidurography, transosseous and intravenous venography, discography, linear tomography, computed tomography, and magnetic resonance imaging. Myelography, epidurography and discography are commonly used, but often lack sensitivity. Myelography is of little value when evaluating the cauda equina because the dural sac is elevated from the vertebral canal floor and frequently ends before the lumbosacral junction. Epidurography will identify a ventrally located compressive lesion and discography can delineate the dorsal extent of the diseased disc; however, both are sometimes difficult to interpret. Therefore, more than one of these imaging techniques must be used in order to make a diagnosis. Computed tomography and magnetic resonance imaging have become valuable in evaluating the lumbosacral region in dogs. These modalities have proven to be both sensitive and specific for determining cauda equina compression in both humans and in dogs.

MRI of the ageing and herniating intervertebral disc

The role of diagnostic imaging from the patient's perspective is to provide answers to four basic questions:--what is wrong?, How bad is it?, Is it clinically relevant?, Can it be treated? In the assessment of spinal disorders, multiple modalities have evolved in an attempt to answer the questions poised. Without doubt, the advent of MRI has given this process significant benefits primarily because of the unparalleled way of depicting normal and abnormal tissues in a non-invasive manner. In particular, MRI is admirably suited to study the intervertebral disc and goes a long way in answering the first two questions, aiding in the accurate analysis of disc morphology, defining pathological states, and delineating the extent and effect of disease. This information however, needs to be equated with the clinical signs and symptoms before any decisions concerning treatment options can be made. At this point one needs to exercise some degree of prudence and remember that MRI as yet does not differentiate abnormal asymptomatic from symptomatic painful disc levels. Enhancement with gadolinium compounds may go some way in providing some answers by defining the tissue response at or around the damaged points within the disco-vertebral unit. Modern MRI scanners and techniques demonstrate exquisitely, the structural status of the disc but the functional impact of these structural alterations cannot as yet be fully determined by MRI--there lies the challenge for the future. This article reviews the current MRI knowledge concerning the ageing and herniating intervertebral disc in a clinical context, and critically appraises its present role in a practical fashion.

Predictive signs of discogenic lumbar pain on magnetic resonance imaging with discography correlation

STUDY DESIGN

The correlation between discogenic lumbar pain and disc morphology was investigated by using magnetic resonance imaging and discography.

OBJECTIVES

To assess the various pathologic parameters seen on magnetic resonance imaging in patients with discogenic lumbar pain and to correlate them with observations on discography.

SUMMARY OF BACKGROUND DATA

Although numerous previous studies on the subject have been performed, the correlations between various pathologic findings on magnetic resonance imaging and pain reproduction by provoked discography have not been explained fully.

METHODS

One hundred and one lumbar discs in 39 patients were studied with magnetic resonance imaging and pain provocation discography. When pain reproduction under discography was concordant, various pathologic parameters on magnetic resonance imaging were analyzed by three statistical parameters to determine the associated magnetic resonance imaging findings.

RESULTS

Radial tears commonly are demonstrated on magnetic resonance imaging in discs with concordant pain on discography. The presence of these tears is not a reliable predictor of a painful disc on discography. Although a high-intensity zone on T2-weighted images is a relatively reliable predictor of pain, the statistical values were lower than those in previous studies. Massive degeneration and severe disc height loss were rare in this population. These findings were good predictors of pain on disc injection.

CONCLUSIONS

Although the lumbar intervertebral discs with posterior combined anular tears are likely to produce pain, the validity of these signs for predicting discogenic lumbar pain is limited.

Familial predisposition for lumbar degenerative disc disease. A case-control study

STUDY DESIGN

A case-control study using magnetic resonance imaging and plain radiography to evaluate whether a family history of lumbar disc herniation is a risk factor for disc degeneration.

OBJECTIVES

To evaluate the significance of a family history of operated lumbar disc herniation in the development of lumbar disc degeneration and lumbar disc herniation.

SUMMARY OF BACKGROUND DATA

There are only a few epidemiologic studies indicating that a family history of intervertebral disc herniation is a risk factor for juvenile disc herniation. Recently, similarities in degenerative findings of the lumbar spine between identical twins have been reported.

METHODS

In the case group, 24 patients who were the immediate relatives of patients who had undergone surgery for disc herniation and who presented or had a history of low back pain and/or unilateral leg pain were included. Control individuals included 72 age- and gender-matched outpatients who reported low back pain and/or leg pain without a family history of operated disc herniation. The incidence, level, and topographic location of disc herniation/diffuse bulge; the incidence and grade of disc degeneration observed on magnetic resonance images; and degenerative changes suggesting disc degeneration observed on plain radiographs were compared between the relatives of patients with disc herniation (cases) and the controls.

RESULTS

The incidence of disc degeneration at L4-L5 and L5-S1 in cases (L4-L5, 18/24; L5-S1, 18/24) and controls (L4-L5, 45/72; L5-S1, 43/72) was similarly high. However, the grade of disc degeneration according to magnetic resonance imaging signal intensity on the T2-weighted sagittal image using Schneiderman's four-grade classification was significantly more severe in cases (L4-L5: Grade 1, 6/24; Grade 2, 4/24; Grade 3, 13/ 24; Grade 4, 1/24; L5-S1: Grade 1, 6/24; Grade 2: 3/24, Grade 3: 12/24, Grade 4: 3/24) than in controls (L4-L5: Grade 1, 27/72; Grade 2, 24/72; Grade 3, 20/72; Grade 4, 1/72; P = 0.034; L5-S1: Grade 1, 29/72; Grade 2, 23/72; Grade 3, 13/72; Grade 4, 7/72; P = 0.023; Mann-Whitney U test). The incidence of disc herniation/diffuse bulge at L4-L5 (16/24) and L5-S1 (11/24) in cases was higher than that in controls (L4-L5, 33/72; P = 0.07; L5-S1, 17/ 72; P = 0.04; chi-square test).

CONCLUSION

The current study provided evidence that a family history of operated lumbar disc herniation has a significant implication in lumbar degenerative disc disease. There may be a genetic factor in the development of lumbar disc herniation as an expression of disc degeneration.

Discography 2000

Discography is an invasive and controversial procedure that can be used as a complementary test to MR imaging or a CT myelogram prior to surgery. The examination may be performed in the prone or decubitus position. Pain provocation is the most important part of the examination. CT discography provides valuable information regarding pattern, number, extent, and degree of annular tears. Correlation of discography with cross-sectional imaging studies is reviewed and the surgical outcome is discussed.

The value of lumbar spine magnetic resonance imaging in the demonstration of anular tears

STUDY DESIGN

Retrospective review of magnetic resonance imaging and discography in patients investigated for low back pain before spinal fusion.

OBJECTIVE

To determine the sensitivity of magnetic resonance imaging in the detection of painful anular tears manifested by the high-intensity zone.

SUMMARY OF BACKGROUND DATA

Two studies have produced results showing that magnetic resonance imaging has a high specificity for the detection of painful anular tears manifested by a high-intensity zone. However, in a recent study, results showed no significant correlation between the high-intensity zone and pain reproduction. The sensitivity of magnetic resonance imaging in identifying anular tears in a symptomatic population has not been determined.

METHODS

Anular tears were identified in magnetic resonance images by the presence of a high-intensity zone in the posterior anulus. The results were compared with the demonstration of painful anular tears on discogram, which has been considered the gold standard.

RESULTS

The study group comprised 58 patients (31 men, 27 women; mean age 42, range 21-63 years). One hundred and fifty-two discs were injected and examined by discography, and 108 were considered degenerate. Of these, 86 had anular tears (54 posterior, 6 anterior, 26 both). Seventy anular tears were associated with concordant pain provocation. Twenty-seven high-intensity zones were identified in magnetic resonance imaging, of which 24 were associated with pain reproduction by discography. The sensitivity, specificity, positive predictive value, and negative predictive value of magnetic resonance imaging in the diagnosis of concordantly painful posterior anular tears are therefore 26.7%, 95.2%, 88.9%, and 47%, respectively.

CONCLUSION

These results confirm that the high-intensity zone is a marker of a painful posterior anular tear. However, the usefulness of this sign is limited by low sensitivity.

Bony vibration stimulation test combined with magnetic resonance imaging. Can discography be replaced?

STUDY DESIGN

The results of two noninvasive methods, magnetic resonance imaging and a bony vibration test, were compared with discographic pain provocation findings.

OBJECTIVES

To evaluate whether the combination of magnetic resonance imaging and vibration pain provocation tests could be used to replace discography in low back pain diagnostics.

SUMMARY OF BACKGROUND DATA

Magnetic resonance imaging gives a wealth of visual information on anatomic changes of the spine with often unknown clinical significance. Discographic examination of the spine is still the only widely accepted diagnostic method that can relate the pathoanatomic changes to the patient's clinical pain. Internal anular rupture has been shown to be one of the sources of back pain. The bony vibration test of the spinal processes has been shown correlate well with discographic pain provocation tests in cases of internal anular rupture.

METHODS

The three lowest lumbar discs of 33 patients with back pain were examined by means of magnetic resonance imaging and a bony vibration stimulation test, and the results were compared with those from computed tomography-discography.

RESULTS

In cases of intradiscal magnetic resonance imaging findings, the vibration provocation test showed a sensitivity of 0.88 and a specificity of 0.50 compared with the discographic pain provocation test. If the patients with previous back surgery were excluded, the specificity was 0.75. In the cases of total anular rupture, the sensitivity was 0.50, and the specificity was 0.33.

CONCLUSION

The combination of the two noninvasive methods, vibration stimulation and magnetic resonance imaging, gives more information on the origin of the back pain than magnetic resonance imaging alone. The pathoanatomic changes seen in magnetic resonance imaging can be correlated with the patient's disorder more reliably using the vibration provocation test in the cases of partial anular ruptures. The use of discography can be limited mostly to cases with total anular ruptures detected by magnetic resonance imaging.

Plain film evaluation of degenerative disk disease at the lumbosacral junction

OBJECTIVE

Diagnosing degenerative disk disease (DDD) at the lumbosacral junction (LSJ) on plain films is often difficult, compared with other disk levels. The purpose of this study was to determine whether criteria for diagnosis of DDD at the LSJ can be established for plain films.

DESIGN AND PATIENTS

We retrospectively reviewed 100 lumbar MRI scans of patients who also had lumbar plain films. Using MRI as the reference standard, the LSJ was classified as normal (n=35) or exhibiting mild (n=45) or severe (n=20) DDD by two radiologists using accepted criteria. Measurements were performed on the plain films by two other radiologists and the average measurements were tabulated according to the three categories of DDD defined by MRI. Plain film measurements included the anterior and posterior disk heights (ADH, PDH), Farfan's ratio, determined by adding ADH to PDH and dividing that number by the measured anteroposterior (AP) length of the inferior end plate of L5 [(ADH+PDH)/AP length of L5], and lumbosacral angle (LSA). Subsequently, five additional radiologists interpreted the radiographs by visual inspection only, for DDD at the LSJ, both before and, several weeks later, after being provided with the quantitative data for normal versus DDD.

RESULTS AND CONCLUSION

There was a statistically significant difference between normal disk and increasing severity of DDD on radiographs using the parameters of PDH and Farfan's ratio. There was no statistically significant difference regarding ADH or LSA. Diagnostic accuracy by visual inspection was not significantly altered using the quantitative data for interpretation of DDD (68% correct before, 69.5% correct after). Analysis of results indicates that PDH is the most reliable and easily used criterion for detection of DDD at the LSJ. A PDH < or =5.4 mm on plain lateral film indicates DDD; PDH > or =7.7 mm indicates the absence of DDD on plain film.

The outcome of posterolateral fusion in highly selected patients with discogenic low back pain

STUDY DESIGN

A prospective analysis of the clinical outcome of a consecutive series of patients treated with posterior lumbar arthrodesis. Preoperative data were collected retrospectively by chart review.

OBJECTIVES

To measure by independent review the clinical outcome of posterolateral intertransverse fusion as a treatment for discogenic low back pain in a highly selected group of patients.

SUMMARY OF BACKGROUND DATA

Although numerous studies have reported on the surgical management of degenerative disc disease, they have been difficult to interpret because they lack patient-oriented outcome assessment and objective pain measurement criteria, independent review, and include patients with diagnoses other than degenerative disc disease.

METHODS

Between 1991 and February 1993 all patients seen by a single surgeon, evaluated with magnetic resonance imaging and discography, and treated with posterolateral lumbar fusion were reviewed by independent investigation. Outcome was assessed in the areas of radiographic fusion, pain, function, and patient satisfaction.

RESULTS

Twenty-three patients (12 women, 11 men; 100% follow-up an average of 47 months after surgery [range, 24-84 months]) met the inclusion criteria. Overall, 39% had a good or excellent result, 13% fair, and 48% poor. Nine of 10 patients receiving worker's compensation had a poor result, four of five patients with radiographic pseudarthrosis had a poor result. Statistically significant improvement in the visual analogue scale was noted in the good and excellent group (P = 0.0001) and the fair group (P = 0.002) with no change in the poor group. Patients out of work more than 3 months before surgery tended to have poor results. Overall, 56% of patients were extremely satisfied with the result of their surgery.

CONCLUSION

Posterolateral intertransverse fusion can be used to successfully manage chronic discogenic back pain. However, patient selection remains a challenge, and successful outcome appears to be limited in the subset of patients receiving worker's compensation and those chronically disabled. Prospective and randomized study with objective pain criteria, independent review, and patient-oriented outcome is recommended.

Lumbar disc high-intensity zone. Correlation of magnetic resonance imaging and discography

STUDY DESIGN

This study correlated a specific lumbar disc abnormality described as the high-intensity zone observed on high-field magnetic resonance imaging with discography.

OBJECTIVES

To analyze the significance of high-intensity zones in lumbar discs of symptomatic patients with low back/radicular pain.

SUMMARY OF BACKGROUND DATA

Aprill and Bogduk described an 86% incidence of concordantly painful discography in lumbar discs exhibiting a posterior high-intensity zone on T2-weighted magnetic resonance imaging studies performed on back pain sufferers. They assert that the high-intensity zone is a reliable marker of discogenic pain in symptomatic subjects.

METHODS

Consecutive cases of lumbar spine high-field magnetic resonance imaging using T2-weighted images on symptomatic patients followed by discography at all high-intensity zone levels and at non-high-intensity zone control levels were reviewed until 100 high-intensity zone discs in 63 patients were found. Seventeen lifelong asymptomatic (for low back/radicular pain) adults were also scanned as magnetic resonance imaging controls. All magnetic resonance scans and discograms were agreed on by at least two of the radiologist authors.

RESULTS

Eighty-seven of 100 of the high-intensity zone discs proved concordantly painful at discography. All 87 painful and concordant discs exhibited abnormal morphology with anular tears extending either well into or through the outer third of the anulus fibrosus. Sixty-five of 67 non-high-intensity zone control discs were nonconcordant and of lower sensation intensity than the high-intensity zone discs. Only one high-intensity zone was found in the control subjects.

CONCLUSIONS

In patients with symptomatic low back pain, the high-intensity zone is a reliable marker of painful outer anular disruption.

Disc degeneration of pediatric patients in lumbar MRI

Magnetic resonance imaging (MRI) is widely used in pediatric spinal disorders, but the prevalence of associated lumbar disc degeneration (DD) has not been evaluated previously. In this study we investigated whether children with suspected spinal disease had increased tendency to early DD. We analyzed lumbar MRI scans of 32 patients and 49 control subjects under 15 years old. Only four patients (13%) had DD on T2-weighted MRI and they were all over 10 years old. Eleven subjects (22%) in the control group had DD. It seems that disc degeneration is seldom found in patients under 10 years old.

The management of chronic spinal pain by blockades: a review

This review of the use of blockades in the diagnosis and symptomatic treatment of spinal pain syndromes is based on increasing knowledge of the innervation of the spine as their rationale. Several clinical syndromes related to the spine are considered. Problems in making a correct diagnosis are discussed. Because of the relative aspecificity of signs and symptoms in spinal pain, a substantial part of the diagnosis may rely on test blockades. The place of test and therapeutic blocks is determined as far as possible. Problems of a pain classification system are discussed. Benefit for the patient depends on the following conditions being achieved: correct diagnosis, careful patient selection, the availability of technical equipment (e.g., fluoroscopy), and a well-designed and well-performed technique in experienced hands.

Disco-computed tomography in extraforaminal and foraminal lumbar disc herniation: influence on surgical approaches

Between January 1990 and February 1992, a total of 301 patients underwent discectomy for lumbar disc herniation; 29 had an extreme lateral herniation, i.e., foraminal or extraforaminal. The intervertebral foramen is a three-dimensional area demarcated primarily by the pedicles; we call it the lateral interpedicular compartment. The extraforaminal zone is the space outside the lateral border of the pedicles. All patients were evaluated by computed tomography (CT), water soluble myelography, postmyelographic CT scanning, or magnetic resonance imaging. Fifteen patients consecutively underwent disco-enhanced CT to adjust a correct diagnosis and to distinguish extraforaminal from foraminal herniation. In 10 cases of extraforaminal herniation, a selective radicular decompression with good-to-excellent clinical results was achieved by an extra-axial lateral decompression of the interpedicular compartment, with preservation of the facet joint. The operative target was the lateral aspect of the pars interarticularis and not the intertransverse space, as previously described. In two cases of both foraminal and extraforaminal herniation, the same technique was used. Fourteen patients with foraminal disc herniation and three patients with both foraminal and extraforaminal herniation underwent a standard intervertebral foraminotomy. An accurate preoperative diagnosis established by disco-CT is crucial in order to select the most suitable surgical approach.

The profile of multiple- versus single-operated patients at the time of their first operation for lumbar disc herniation

A retrospective study was carried out on a total of 491 patients (294 male, 197 female) who underwent surgery between 1 January 1980 and 31 December 1986. They were treated by minimal intervention lumbar discectomy without the use of a microscope. The patient groups consisted of 241 patients who needed a second operation (MOP, multiple operations) and another 250 patients who needed only one surgical procedure (SOP, single operation) and the whole treatment period was between 1 January 1980 and 31 December 1990. The SOP patients served as control group. The MOP and SOP groups were compared in the search for clinical and/or morphological parameters which might distinguish the two groups at the time of first operation.

RESULTS

In terms of history, age, sex distribution, pre-operative treatment and severity of neurological symptoms there was no statistical difference between the two groups at the time of the first operation. Radiological examinations were more extensive but less conclusive in the MOP group. In the SOP patients, subligamentous and epidural disc fragments occurred in 67.2% of patients. In the MOP patients disc protrusions or small subligamentous extrusions were predominant (50.1%) at the time of the first operation. Osteochondritic changes occurred less frequently in the MOP (39.1% vs 53.6%). There were significantly more two-level approaches in the MOP patients (31.5% vs 14.4%); also, the surgical technique in the MOP group was less invasive, often being 'explorative' in character. Post-operative morbidity was higher, improvement of neurological symptoms was slower and the overall result was worse in MOP patients after the first operation. Interpretation of radiological findings, disc morphology and surgical technique are usually considered factors influencing the outcome of disc surgery. At the second operation (MOP 2) there were epidural scars in 48.4% of patients and the incidence of disc fragments containing parts of the end-plate increased from 10.1% to 61.9%. The prognosis was worse in patients with mild pre-operative disc degeneration.

Magnetic resonance imaging in the diagnosis of degenerative lumbosacral stenosis in four dogs

Magnetic resonance imaging was used to diagnose degenerative lumbosacral stenosis in four dogs that had physical and neurologic signs consistent with a cauda equina lesion. Nerve root displacement by protruding disc material and loss of epidural fat were identified. In all dogs, the diagnosis was confirmed by dorsal laminectomy of the lumbosacral area.

Diagnosis of cauda equina abnormalities by using electromyography, discography, and epidurography in dogs

Electromyography (EMG), L7-S1 discography and epidurography were investigated in 15 dogs with clinical signs of cauda equina dysfunction and in 7 control dogs without such clinical signs. Electromyography of paraspinal and pelvic limb muscles was done in 13 of 15 affected dogs. An L7-S1 discogram followed by an epidurogram was performed in all 22 dogs using 20% iopamidol. Results of discograms, epidurograms, and gross necropsy examinations were normal in six of seven control dogs. The one dog in which these studies were abnormal had a mild L7-S1 disc protrusion that did not result in nerve root compression at necropsy. Electromyographic analysis was 100% accurate in predicting the presence or absence of cauda equina disease. None of the results of discograms were falsely negative. Twelve of 15 discograms in clinically affected dogs indicated dorsal disc protrusion, but 2 of these protrusions were found to be noncompressive at surgery (13% error). Abnormal epidurograms occurred in 9 of 15 clinically affected dogs. There was one false positive and two false negatives (20% error). Electromyography was a sensitive screening technique for the presence of cauda equina disease. Discography may be more sensitive for detection of L7-S1 disc protrusion than epidurography. An abnormal radiographic contrast study of the cauda equina may only be useful when combined with an abnormal EMG.

Lumbosacral spine imaging: physioanatomic method

Noninvasive evaluation of low back and leg pain has progressed rapidly over the past decade. The development of computed tomography, single-photon emission-computed tomographic bone scan, and magnetic resonance imaging has markedly increased diagnostic accuracy in detecting pathologic conditions. With this increased accuracy has come recognition of a 50% prevalence of underlying abnormalities in patients between 20 and 60 years old who have no symptoms. When such patients have a back injury, subsequent imaging will show in half of the population studied abnormalities that are not related to an acute injury. Degeneration of the spine progresses in all patients throughout their lifetime, and nearly all of the population will have back discomfort at some time. Political- and judicial-based compensation for back injuries related to accidents and on-the-job injuries provides an incentive for patients not to improve on therapy and to exaggerate symptoms, further complicating the clinical evaluation of their condition. The goal of physioanatomic noninvasive and invasive imaging evaluation presented in the following chapters is to increase specificity by differentiating pain generators from asymptomatic underlying pathologic conditions. When used with intensive conservative management and psychologic testing, this physioanatomic approach has resulted in much better treatment outcomes in our experience. The physioanatomic approach is quite simple, consisting of rigorous correlation of pathologic changes demonstrated by noninvasive imaging modalities (computed tomography, single-photon emission-computed tomographic bone scan, and magnetic resonance), or invasive modalities (diskography-enhanced computed tomography, nerve root block and facet block) with the patient's symptoms to evaluate whether the symptoms and the pathologic lesion are concordant or discordant. Patient symptoms and history are evaluated by use of a pain drawing and information sheet. The patient's pain pattern is categorized into a nonspecific pattern or into one of four recognizable pathway patterns (radicular, dorsal ramus, polyneuropathy, and sympathetic). Because each spinal lesion is typically manifested primarily via one of the four symptom pathways, the distribution of expected symptoms from each pathologic feature can be compared with the patient's pain drawing, and an assessment of the significance of imaged lesions can be made. The patient's presenting symptoms are also used to determine the most cost-effective and efficacious use of initial diagnostic imaging evaluation. In a minority of patients the findings on noninvasive imaging either will not correlate with the patient's symptoms or will demonstrate multiple abnormalities that could account for the patient's symptoms. In these patients, invasive techniques are extremely helpful in defining a pain generator or pain generators.(ABSTRACT TRUNCATED AT 400 WORDS)

Correlating magnetic resonance imaging with the biochemical content of the normal human intervertebral disc

Magnetic resonance imaging was used to determine the T2 relaxation times of prepared proteoglycan solutions and of normal human intervertebral disc tissue from the annulus fibrosus (AF) and nucleus pulposus (NP). The collagen, proteoglycan, and water contents of the disc tissue samples were determined by biochemical assays after they were scanned. Correlations among 1/T2, collagen, proteoglycan, and water contents of the tissue samples and among 1/T2, water, and proteoglycan contents of the proteoglycan solutions were calculated. A moderate negative correlation between 1/T2 and water content was noted for the tissue samples, and a very high negative correlation was found between 1/T2 and water content for the proteoglycan solutions. The very high positive correlation between 1/T2 and proteoglycan content of the proteoglycan solutions is probably due to this negative correlation between 1/T2 and water content. There was no significant correlation between 1/T2 and proteoglycan content of the tissues. The moderate positive correlation between 1/T2 and collagen content is probably due to the high negative correlation between collagen content and water content. No significant correlation was found between the collagen and proteoglycan contents of the tissues. Thus it appears that the data confirm previous reports in the literature that the collagen of the disc tissue functions to control its water content.