Anular Tears Research Articles

Occurrence of discal and non-discal changes after sequestrectomy alone versus sequestrectomy and implantation of an anulus closure device

Sequestrectomy alone represents a procedure for the treatment of lumbar disc herniation. For selected cases, an anulus closure device (ACD) can be implanted which may result in lower reoperation rates. However, comparative magnetic resonance imaging (MRI) changes and their clinical relevance of both procedures are unclear and have not been reported so far.Clinical and MRI data of patients after limited discectomy with ACD implantation (group ACD; N=45) and patients after sequestrectomy alone (group S; N=40) with primary lumbar disc herniation were compared retrospectively. Pain intensity on the visual analogue pain scale (VAS), oswestry disability index (ODI) or the patient satisfaction index (PSI) were collected. Disc signal intensity, Modic type changes, endplate reactions, anular tears and reherniations were investigated using MRI before and <18months postoperative. Morphologic changes were correlated with clinical outcome.There was no difference in VAS back, VAS leg or ODI/PSI after the operation although group S showed significantly more reherniations in MRI. The overall rate of repeated surgery at the same level was similar with a trend in favour of the ACD group (P=0.729). Significantly more patients of the ACD group experienced endplate erosions after surgery (P<0.001). Both groups experienced progression of disc signal intensity, Modic type changes, and anular tears with most MRI signs being without clinical relevance.ACD implantation is associated with a significantly lower reherniation rate in MRI but showed a significantly higher rate of endplate erosions. The structural changes do not appear to be clinically relevant.

Prospective study of disc repair with allogeneic chondrocytes Presented at the 2012 Joint Spine Section Meeting

The purpose of the study was to evaluate the safety and initial efficacy of NuQu allogeneic juvenile chondrocytes delivered percutaneously for the treatment of lumbar spondylosis with mechanical low-back pain (LBP). NuQu is a cell-based biological therapy for disc repair. The authors report the results at 12 months of the NuQu Phase I investigational new drug (IND) single-arm, prospective feasibility study for the treatment of LBP for single-level degenerative disc disease (Pfirrman Grades III-IV) at L3-S1. Fifteen patients (6 women and 9 men) were enrolled at 2 sites. Institutional review board approval was obtained, and all patients signed a study-specific informed consent. All patients have completed a minimum of 1 year of follow-up. Patients were evaluated pretreatment and at 1, 3, 6, and 12 months posttreatment. Evaluations included routine neurological examinations, serum liver and renal function studies, MRI, the Oswestry Disability Index (ODI), the Numerical Rating Scale (NRS), and the 36-Item Short Form Health Survey (SF-36). Fifteen patients were treated with a single percutaneous delivery of NuQu juvenile chondrocytes. The mean patient age was 40 years (19-47 years). Each treatment consisted of 1-2 ml (mean injection 1.3 ml) of juvenile chondrocytes (approximately 10(7) chondrocyte cells/ml) with fibrin carrier. The mean peak pressure during treatment was 87.6 psi. The treatment time ranged from 5 to 33 seconds. The mean ODI (baseline 53.3, 12-month 20.3; p < 0.0001), NRS (baseline 5.7, 12-month 3.1; p = 0.0025), and SF-36 physical component summary (baseline 35.3, 12-month 46.9; p = 0.0002) scores all improved significantly from baseline. At the 6-month follow-up, 13 patients underwent MRI (one patient underwent CT imaging and another refused imaging). Ten (77%) of these 13 patients exhibited improvements on MRI. Three of these patients showed improvement in disc contour or height. High-intensity zones (HIZs), consistent with posterior anular tears, were present at baseline in 9 patients. Of these, the HIZ was either absent or improved in 8 patients (89%) by 6 months. The HIZ was improved in the ninth patient at 3 months, with no further MRI follow-up. Of the 10 patients who exhibited radiological improvement at 6 months, findings continued to improve or were sustained in 8 patients at the 12-month follow-up. No patient experienced neurological deterioration. There were no disc infections, and there were no serious or unexpected adverse events. Three patients (20%) underwent total disc replacement by the 12-month follow-up due to persistent, but not worse than baseline, LBP. This is a 12-month report of the clinical and radiographic results from a US IND study of cell-based therapy (juvenile chondrocytes) in the treatment of lumbar spondylosis with mechanical LBP. The results of this prospective cohort are promising and warrant further investigation with a prospective, randomized, double-blinded, placebo-controlled study design. Clinical trial registration no.: BB-IND 13985.

Discal Cyst in Pediatric Patients: Case Report and Review of the Literature

Discal (intraspinal extradural) cysts which communicate with intervertebral disk are uncommon cause of lumbar radiculopathy, especially in pediatric patients. Only three pediatric cases have been reported in the literature. A 15-year-old boy presented with acute onset left-sided S1 radiculopathy. Magnetic resonance imaging of the lumbar spine revealed a well-defined round extradural mass seated in the left ventrolateral epidural space of the spinal canal behind the S1 vertebral body. He did not respond to the conservative therapies. Because of persistent left S1 radiculopathy, left laminotomy was performed at L5-S1 level with coagulation of the posterior longitudinal ligament surrounding the anular tear; however, discectomy was not done. The symptoms resolved and no recurrence was found at 7-year follow-up. The clinical manifestations, imaging findings, possible pathogeneses, and treatment options of these lesions are discussed and the relevant literature is reviewed.

Annulus Fissures Encourage Blood Vessel and Nerve Ingrowth into Degenerated Intervertebral Disks

Introduction Discogenic back pain is closely associated with fissures in the annulus fibrosus,1,2 and with ingrowth of nerves and blood vessels.3 We test the hypothesis that annulus fissures encourage such ingrowth. Materials and Methods Three complementary studies were performed. Firstly, 15 cadaveric disks that contained an annulus fissure were subjected to 1 kN compression, while a miniature pressure transducer was pulled through the disk to obtain distributions of matrix compressive stress perpendicular to the fissure axis. Secondly, safranin O staining was used to evaluate focal loss of proteoglycans from within annulus fissures in 25 surgically removed disk samples. A novel image analysis method was used to quantify proteoglycan concentration along a line profile that was perpendicular to the fissure axis. Thirdly, in 21 elderly cadaveric disks, proteoglycan and water concentration were measured biochemically in disrupted regions of annulus containing one or more fissures, and in adjacent intact regions. The second experiment had good spatial resolution but was unable to quantify proteoglycan loss precisely, whereas the third experiment had poor spatial resolution but allowed precise quantification of proteoglycan loss. Results Reductions in compressive stress within annulus fissures averaged 36&gt;46%, and were greater than average at the fissure axis. Stress reductions were greater in degenerated disks, and were inversely related to nucleus pressure (R2 = 0.47, p &lt; 0.005). Safranin O stain intensity indicated that proteoglycan concentration was typically reduced by 40% at a distance of 600 µm from the fissure axis, and the width of the proteoglycan-depleted zone increased with age (R2 = 0.29, p = 0.006) and with general proteoglycan loss (R2 = 0.32, p &lt; 0.005). Disrupted regions of annulus contained 36 to 54% less proteoglycans than adjacent intact regions from the same disks, although water content was reduced only slightly ( p &gt; 0.05). Conclusion Annulus fissures provide a low-pressure microenvironment, especially if there is insufficient fluid pressure in the disk nucleus to tension the annulus and prevent fissures from “opening up.” A disk's collagen network is disrupted within an annulus fissure, and this disruption, combined with low pressure, permits local tissue swelling even though some of the proteoglycans are lost in the process. Blood vessels are attracted into this microenvironment by a combination of low pressure (which is less likely to collapse hollow blood vessels than a high pressure) and by a low concentration of proteoglycans, which are known to inhibit blood vessel4 and nerve5 ingrowth. Finally, nerve ingrowth into annulus fissures is facilitated by the presence of blood vessels, and by the low proteoglycan concentration. In this way, an annulus fissure in a degenerated intervertebral disk comprises a distinct microenvironment that is mechanically and chemically conducive to nerve and blood vessel ingrowth. This can explain the close association between annulus fissures and suspected discogenic back pain. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared Videman T, Nurminen M. The occurrence of anular tears and their relation to lifetime back pain history: a cadaveric study using barium sulfate discography. Spine 2004;29(23):2668–2676 Peng B, Wu W, Hou S, Li P, Zhang C, Yang Y. The pathogenesis of discogenic low back pain. Journal of Bone and Joint Surgery British Volume 2005;87(1):62–67 Freemont AJ, Peacock TE, Goupille P, Hoyland JA, O'Brien J, Jayson MI. Nerve ingrowth into diseased intervertebral disk in chronic back pain. Lancet. 1997;350(9072):178–1781 Johnson WE, Caterson B, Eisenstein SM, Roberts S. Human intervertebral disk aggrecan inhibits endothelial cell adhesion and cell migration in vitro. Spine 2005;30(10):1139–1147 Johnson WE, Caterson B, Eisenstein SM, Hynds DL, Snow DM, Roberts S. Human intervertebral disk aggrecan inhibits nerve growth in vitro. Arthritis and Rheumatism 2002;46(10):2658–2664

Value of 3D MR Lumbosacral Radiculography in the Diagnosis of Symptomatic Chemical Radiculitis

Radiologic methods for the diagnosis of chemical radiculitis associated with anular tears in the lumbar spine have been rare. Provocative diskography is one of the methods for diagnosing diskogenic chemical radiculitis but is invasive. A reliable imaging method for replacing provocative diskography and diagnosing chemical radiculitis is required. Our aim was to investigate the value of 3D MR radiculography depicted by rendering imaging in the diagnosis of symptomatic chemical radiculopathy associated with anular tears. The study population consisted of 17 patients (age range, 32-88 years) with unilateral radiculopathy. Symptomatic chemical radiculopathy was confirmed with provocative CT diskography and/or provocative selective nerve root block for agreement of sides and levels. Through adhering to the principles of selective excitation (Proset imaging), we acquired 3D coronal FFE sequences with selective water excitation. Morphologic changes in the ipsilateral symptomatic nerve root caused by chemical radiculopathy were compared with those in the contralateral nerve root on 3D MR lumbosacral radiculography. Pain reproduction at the contrast-leak level during diskography (n = 4) and selective nerve root injection (n = 13) showed concordant pain in all patients. All patients with symptomatic chemical radiculopathy showed nerve root swelling in both ipsilateral levels and sides on 3D MR radiculography. The most common nerve root affected by the chemical radiculopathy was the L5 nerve root (n = 13), while the most common segment exhibiting nerve root swelling was the exit nerve root (n = 16). All patients with radicular leg pain caused by chemical radiculopathy showed nerve root swelling on 3D MR radiculography. We believe that in cases without mechanical nerve root compression caused by disk herniation or stenosis in the lumbar spine, nerve root swelling on 3D MR radiculography in patients with radiculopathy associated with an anular tear may be relevant in the diagnosis of symptomatic chemical radiculopathy.

Does Lumbar Disc Degeneration on Magnetic Resonance Imaging Associate With Low Back Symptom Severity in Young Finnish Adults?

A cross-sectional magnetic resonance imaging study with questionnaires on low back pain (LBP) and functional limitations. To investigate the association between lumbar intervertebral disc degeneration (DD) and low back symptom severity among young Finnish adults. Both LBP and lumbar DD are common already in adolescence, but very little is known of their association in young adults. Young adults belonging to a birth cohort (n=874) were invited to lumbar magnetic resonance imaging using a 1.5-T scanner. Data on LBP and functional limitations at the ages of 18, 19, and 21 years were used to cluster the subjects with respect to low back symptoms using latent class analysis. The prevalence and 95% confidence intervals of DD at 21 years and the sum score of DD at all lumbar levels were compared between the clusters. The contribution of DD and other imaging findings (herniations, anular tears, Modic changes, spondylolytic defects) to symptom severity was analyzed with logistic regression analysis. Latent class analysis produced five clusters from the 554 subjects, ranging from a cluster where subjects (n=65) had been painful at all time points to an asymptomatic cluster (n=168). DD was more prevalent in the three most symptomatic clusters compared to the two least symptomatic ones. Similar findings were obtained for the DD sum scores. Lumbar DD was related to symptom severity independently of other degenerative findings. Moreover, moderately degenerated discs were more likely than mildly degenerated discs to be associated with the most severe low back symptoms. Intervertebral DD was associated with low back symptom severity among young adults, suggesting that the symptoms may have a discogenic origin at this age. However, DD was also found in one-third of asymptomatic subjects.

Temporal Interactions of Degenerative Changes in Individual Components of the Lumbar Intervertebral Discs

A retrospective longitudinal observational study using baseline and follow-up magnetic resonance imaging (MRI). To study the natural history of disc degeneration, focusing on the significance of changes affecting the individual components of the intervertebral disc. The natural history of the degenerative disc disease is poorly understood. Focusing on the relative prevalence, temporal evolution, and interactions of pathology in the anulus fibrosus, nucleus pulposus, and the end plates can help in better understanding of this process. MRIs of the lumbar spine in 63 patients, obtained at a mean interval of 30 months, were evaluated independently by two neuroradiologists to assess the temporal evolution of degeneration changes in 378 discs between T12 through S1 segments. In addition, a direct side-by-side comparison of two studies was also performed. Statistical analysis was performed to assess the association between the degeneration of individual disc components and to find the predictors of future degeneration. Radial anular tears and end plate defects were associated with worse nuclear degeneration at the time of the initial study. Both end plate defects and nuclear degeneration were rare in the absence of radial tears. Multiple nominal logistic regression analysis showed that radial tears and herniation at the time of the initial study, along with the duration between the two imaging studies were the significant predictors of worsening nuclear degeneration. Age, sex, and the segmental disc level did not show any significant association with temporal progression of nuclear degeneration. Radial tears and herniation are significant predictors of progressive nuclear degeneration, which was not seen in the absence of radial tears. End plate defects also frequently occur before nuclear degeneration but rarely in the absence of anular tears.

Innervation of Anulus Tears

A prospective immunohistological study in an animal model. To identify and describe the phenotype of neoinnervation in experimental anular tears. Controversy surrounds neoinnervation of degenerate discs which has been proposed as the anatomic basis for discogenic pain. Ablation of neoinnervation has been postulated as the theoretical basis for the claimed successes of procedures such as intradiscal electrotherapy. The animal model of disc degeneration previously developed in our research center provides an opportunity to investigate the innervation of anular tears in an extensively characterized lesion. A surgical anular tear was created in 5 lumbar discs in 11 sheep which were killed at 1, 2, 3, and 12 months. Each spine was x-rayed and divided into motion segments for histologic analysis. Serial sections through the tear were immunostained for protein gene product 9.5, tyrosine hydroxylase, and calcitonin gene receptor protein. Neoinnervation of the periphery of the anular tear was observed. Ingrowing nerves penetrated marginally deeper than the normal anular innervation but no nerves were identified in the inner anulus or nucleus. A minority of the new axons were calcitonin gene receptor protein or tyrosine hydroxylase positive. The anulus tears in this model are innervated only peripherally to a depth only marginally greater than that of the normal anulus.

Prevalence of Degenerative Imaging Findings in Lumbar Magnetic Resonance Imaging Among Young Adults

A cross-sectional imaging study of young adults. To investigate the prevalence of disc degeneration (DD) and displacement, anular tears, and Modic changes in lumbar magnetic resonance imaging (MRI) among young adults. Although low back pain in young adulthood is common, the prevalence of spinal MRI findings at this age remains virtually unknown. The study population was a subcohort of the Northern Finland Birth Cohort 1986. Subjects living within 100 km of Oulu (n = 874) were invited to participate in lumbar MRI at 20 to 22 years of age (mean: 21.2 years). Degree of DD, type of Modic changes, and presence of disc bulges, herniations, high intensity zone (HIZ) lesions, and radial tears at all lumbar levels were assessed. Three hundred twenty-five women and 233 men (n = 558) attended the MR imaging. DD was significantly more frequent in men (54% vs. 42%, P = 0.005), as was multiple DD (21% vs. 14%, P = 0.036). The prevalences of disc bulges and radial tears were 25% and 9.1%, respectively, without gender differences. HIZ lesions were more common among women than men (8.6% vs. 4.3%, P = 0.046), whereas herniations were significantly more common among men (5.6% vs. 2.5%, P = 0.047). Only 2 disc extrusions were observed, one in each gender. All degenerative disc findings were more common at the L5-S1 level except HIZ lesions, which were most likely at L4-L5. The prevalence of the Modic changes was 1.4%, without gender difference, type I being more common than type II. Typically, Modic changes were located adjacent to a DD Grade 4 disc and at the 2 lowest levels. Almost half of young Finnish adult aged 21 years had at least one degenerated disc, and a quarter had a bulging disc. Modic changes and disc herniations were, however, relatively rare.

Prevalence and Pattern of Lumbar Magnetic Resonance Imaging Changes in a Population Study of One Thousand Forty-Three Individuals

A cross-sectional population study of magnetic resonance imaging (MRI) changes. OBJECTIVE.: To examine the pattern and prevalence of lumbar spine MRI changes within a southern Chinese population and their relationship with back pain. Previous studies on MRI changes and back pain have used populations of asymptomatic individuals or patients presenting with back pain and sciatica. Thus, the prevalence and pattern of intervertebral disc degeneration within the population is not known. Lumbar spine MRIs were obtained in 1043 volunteers between 18 to 55 years of age. MRI changes including disc degeneration, herniation, anular tears (HIZ), and Schmorl's nodes were noted by 2 independent observers. Differences were settled by consensus. Disc degeneration was graded using Schneiderman's classification, and a total score (DDD score) was calculated by the summation of the Schneiderman's score for each lumbar level. A K-mean clustering program was used to group individuals into different patterns of degeneration. Forty percent of individuals under 30 years of age had lumbar intervertebral disc degeneration (LDD), the prevalence of LDD increasing progressively to over 90% by 50 to 55 years of age. There was a positive correlation between the DDD score and low back pain. L5-S1 and L4-L5 were the most commonly affected levels. Apart from the usual patterns of degeneration, some uncommon patterns of degeneration were identified, comprising of subjects with skip level lesions (intervening normal levels) and isolated upper or mid lumbar degeneration. LDD is common, and its incidence increases with age. In a population setting, there is a significant association of LDD on MRI with back pain.

Significance of Perianular Enhancement Associated With Anular Tears on Magnetic Resonance Imagings in Diagnosis of Radiculopathy

Retrospective analysis of magnetic resonance imaging (MRI) and clinical findings about chemical radiculitis-associated anular tear in patients with radiculopathy. To investigate MRI findings of the chemical radiculitis caused by anular tears and to determine whether chemical radiculitis detected by MRI is the cause of radiculopathy. Many studies document that irritation of adjacent nerve roots by a chemical mediator of inflammation from the nucleus pulposus may result in radiculopathy. Computed tomography (CT) discography may be the best examination for diagnosing discogenic chemical radiculitis but is too invasive. A reliable imaging method for replacing invasive provocative CT discography and diagnosing chemical radiculitis is required. The study population consisted of 12 patients with pain referred to leg(s) with or without low back pain who underwent lumbar spine MRI. All cases of our study demonstrated perianular enhancement caused by chemical radiculitis associated with anular tears. Patterns and locations of perianular enhancement adjacent to anular tears on MRI were assessed. MRI findings were compared with clinical symptoms and/or provocative transforaminal epidural injection (n = 6). For documentation of the relationship between perianular enhancement and radiculopathy, provocative CT discography was performed in 2 cases. Perianular enhancement associated with anular tears revealed thick linear patterns (2.5-7 mm thickness) along margins of anular tears on contrast enhanced axial T1-weighted images with fat suppression. Locations of perianular enhancement adjacent to anular tears were at foraminal (n = 6) and extraforaminal portions (n = 6). CT discography showed a leak of contrast from anular tear to the perianular regions. Pain reproduction at contrast leak level during discography showed concordant pain. There was an apparent correlation between perianular enhancement on MRI and clinical symptoms or provocative epidural nerve root injection in all cases. The perianular enhancement adjacent to anular tears on MRI may be relevant in the diagnosis of symptomatic chemical radiculitis.

The In Vivo Biological Effects of Intradiscal Recombinant Human Bone Morphogenetic Protein-2 on the Injured Intervertebral Disc

Prospective analysis. To investigate biologic influences of recombinant human bone morphogenetic protein (rhBMP)-2 on intervertebral discs after anular tears. Treatments for intervertebral disc injury or degeneration are unsatisfactory. rhBMP-2, a high-potency osteoinductive and chondroinductive substance, is approved for use in anterior lumbar interbody fusions. rhBMP-2 stimulates the proliferation of rat disc cells and the secretion of extracellular matrix in vitro. In vivo responses in the intervertebral disc after anular tears are rarely studied. Twenty New Zealand white rabbits received full-thickness anular tears and intradiscal injections of saline (control) and rhBMP-2 0.1 mg with and without coral grafts at L2-L3, L3-L4, and L4-L5, respectively. Three died or had infection. Therefore, 17 underwent radiography and sacrifice at 12 weeks. Spinal sections were stained with hematoxylin and eosin to examine responses to rhBMP-2. Radiographs revealed degenerative changes, such as disc space narrowing and irregularity, subchondral sclerosis, osteophyte formation, and hypertrophy of vertebral endplates in all groups. Degeneration was more frequent and severe with rhBMP-2 with (P < 0.01) and without (P < 0.05) coral than with saline. Two rabbits receiving rhBMP-2 and coral achieved solid interbody bony fusion. New bone formation was noted in 2 controls, in 3 animals treated with rhBMP-2, and in 4 treated with rhBMP-2 and coral. Vascularity and fibroblast proliferation increased with rhBMP-2 (n = 14) and rhBMP-2 with coral (n = 9) compared with control (n = 3; P < 0.01 and P = 0.03, respectively). Inflammatory infiltrates increased with rhBMP-2 (n = 8) compared with control (n = 2; P = 0.03). Degenerative changes were more frequent and severe in the groups treated with rhBMP-2 with or without coral in radiographic findings. In histopathologic findings, rhBMP-2 promoted hypervascularity and fibroblast proliferation of the intervertebral disc after an anular tear.

The Course of Macroscopic Degeneration in the Human Lumbar Intervertebral Disc

Assessment of age-related macroscopic changes in human lumbar intervertebral discs (IVD) and vertebral bodies. To determine the sequence of macroscopic changes during aging/degeneration. Descriptive studies on macroscopic alterations of the IVD during aging/degeneration are readily available, but quantitative analyses are sparse. A total of 248 mid-/parasagittal sections of lumbar IVD and vertebral bodies from 41 routine autopsies (range, 7 months to 88 years) were semiquantitatively assessed for macroscopic parameters and correlated with age. Nuclear fibrous transformation, anular disorganization, endplate, and vertebral body alterations progress predominantly in the first two and in the fifth to seventh decades. In the third and fourth decade, little progression occurs. Nuclear clefts and anular tears appear later, mostly starting in the second decade, with clefts preceding tear formation. Radial and concentric tears develop similarly over time, whereas rim lesions mostly develop after the sixth decade. Significant differences are observed between upper and lower lumbar spine. Our data show that fibrous nuclear transformation during aging/degeneration precedes cleft formation. The temporal sequence suggests a strong correlation of cleft and tears formation starting with clefts in the second decade. Our results support the hypothesis that disc degeneration starts in the nucleus. Extensive macroscopic alterations already apparent in the second life decade present a challenge to any tissue engineering and repair attempt.

Association of the Taq I Allele in Vitamin D Receptor With Degenerative Disc Disease and Disc Bulge in a Chinese Population

Large scale, case-control study. To assess the effect of the Taq I alleles in vitamin D receptor on the risk of developing degenerative disc disease in a Southern Chinese population. Previous studies in Finns and Japanese suggest that the Taq I polymorphism of vitamin D receptor is associated with the development of degenerative disc disease in the lumbar spine. However, sample sizes were small, and the results need to be confirmed in other populations. Lumbar degenerative disc disease was defined by magnetic resonance imaging (MRI) on 804 Southern Chinese volunteers between 18 and 55 years of age. Restriction enzyme digestion of polymerase chain reaction products was used to analyze the Taq I alleles. The resulting genotypes were correlated with the presence of lumbar disc degeneration and bulge on MRI. Using logistic regression analysis and adjusting for age and sex, the t allele of Taq I in vitamin D receptor gene was significantly associated with degenerative disc disease, with an odds ratio (OR) of 2.61 (95% confidence interval [CI] 1.15-5.90, P = 0.041). Further subgroup analysis showed that in individuals younger than 40 years, the OR was even higher, at 5.97 (95% CI 1.69-21.15, P = 0.002). Similarly, disc bulge was significantly associated with t allele (OR = 7.17, 95% CI 1.43-36.01, P = 0.001) in individuals younger than 40 years. Anular tears and the Schmorl nodes were not associated with the t allele of Taq I polymorphism. To our knowledge, this is the largest scale genetics study to date using MRI to define precisely degenerative disc disease in the Southern Chinese population. We showed that the t allele of vitamin D receptor Taq I is associated with a high risk of degenerative disc disease and disc bulge developing, especially in individuals younger than 40 years.

Determinants of the Progression in Lumbar Degeneration

A 5-year follow-up study of exposure of discordant monozygotic twin pairs with repeated interviews and spine imaging. The primary goals were to record changes in the degenerative signs over a 5-year interval and to estimate the effects of familial influences and suspected environmental risk factors on the speed of lumbar degeneration. Traditionally, disc degeneration has been attributed to aging and environmental exposures; recently, a dominant effect of genetics has been revealed. Yet the etiopathogenesis of disc degeneration remains poorly understood and controversial despite being a primary target of diagnostic and therapeutic interventions. Among 116 monozygotic twin pairs, which had been examined 5 years earlier, 75 pairs (150 men) were reexamined. They were imaged using the same MRI scanner and examination protocol as at baseline. The data were analyzed using statistical methods for longitudinal studies. Progression in disc height narrowing, disc bulging, osteophytosis, and fatty degeneration in the lumbar spine was seen in about 7% to 13% of the discs in 7% to 46% of subjects during 5-year follow-up. Few degenerative findings appear to reverse; few disc height measures increased, some anular tears were no longer visible, and bulging/herniation diminished. New anular tears (in axial view) were detected in 1.5%, disappeared in 2%, and were unchanged in 5.3% of discs; in the sagittal view, new high intensity zones findings were identified in 0.5%, were no longer apparent in 1.6%, and were unchanged in 7.1% of discs. There were no clear changes in upper endplates: in 2.1% of discs, the irregularity score increased and in 1.8% it decreased. Familial aggregation, reflecting genetic, and shared environmental influences, explained 47% to 66% of the variance in progression of degenerative signs on lumbar MRI, and resistance training and occupational physical loading together explained 2% to 10% of the progression in the degenerative signs in lumbar MRIs. Progression of disc height narrowing, bulging, osteophytes, and fatty degeneration was detected in about 10% or less of the T12-S1 discs. Development and disappearance of anular lesions were rarer. No clear changes were seen in endplate irregularities. The results also confirm that hereditary effects have a dominant role in the progression of disc degeneration and suggest that occupational lifting and leisure time resistance training have modest additional effects.

The TRP2 Allele of COL9A2 is an Age-Dependent Risk Factor for the Development and Severity of Intervertebral Disc Degeneration

Low back pain (LBP) and sciatica are usually caused by degenerative disc disease (DDD). Although they are common, the etiology of these conditions is poorly understood. A large population case-control study in the Southern Chinese was performed to study genetic risk factors to DDD. To gain a better understanding of the etiology of DDD in relation to structural defects of the intervertebral disc. A Finnish study found an association between LBP and sciatica with two variants of the alpha-chains of collagen IX, encoded by the Trp2 and Trp3 alleles, representing Gln326Trp and Arg103Trp amino acid substitutions in the COL9A2 and COL9A3 genes, respectively. Trp2 was found only in affected individuals (4%), whereas Trp3 was present in both affected (24%) and unaffected (9%) individuals. Because of the low frequency of the Trp2 allele in whites, the significance and contribution of this allele to DDD are not known. Using more objective criteria to define the disease by magnetic resonance imaging (MRI), we tested these alleles for association with DDD in a large population study. Lumbar DDD, the presence of anular tears, and disc and endplate herniations were defined by MRI in 804 Southern Chinese volunteers 18 to 55 years of age. These were correlated with the frequencies of the Trp2 and Trp3 alleles. The Trp2 allele was present in 20% of the population and was associated with a fourfold increase in the risk of developing anular tears at 30 to 39 years and a 2.4-fold increase in the risk of developing DDD and endplate herniations at 40 to 49 years. Affected Trp2 individuals had more severe degeneration. The Trp3 allele was absent from the Southern Chinese population. This largest-ever population study using MRI to define DDD demonstrates for the first time that the Trp2 allele is a significant risk factor for the development and severity of degeneration. The association is age- dependent as it is more prevalent in some age groups than in others. The contrasting Trp allele frequencies between the Finns and the Chinese are the first indication that the genetic risk factors for DDD varies between ethnic groups.

A Randomized, Double-Blind, Controlled Trial

A prospective, randomized, double-blind, placebo-controlled trial of intradiscal electrothermal therapy (IDET) for the treatment of chronic discogenic low back pain (CDLBP). To test the safety and efficacy of IDET compared with a sham treatment (placebo). In North America alone, more than 40,000 intradiscal catheters have been used to treat CDLBP. The evidence for efficacy of IDET is weak coming from retrospective and prospective cohort studies providing only Class II and Class III evidence. There is one study published with Class I evidence. This demonstrates statistically significant improvements following IDET; however, the clinical significance of these improvements is questionable. Patients with CDLBP who failed to improve following conservative therapy were considered for this study. Inclusion criteria included the presence of one- or two-level symptomatic disc degeneration with posterior or posterolateral anular tears as determined by provocative computed tomography (CT) discography. Patients were excluded if there was greater than 50% loss of disc height or previous spinal surgery. Fifty-seven patients were randomized with a 2:1 ratio: 38 to IDET and 19 to sham procedure (placebo). In all cases, the IDET catheter was positioned to cover at least 75% of the annular tear as defined by the CT discography. An independent technician connected the catheter to the generator and then either delivered electrothermal energy (active group) or did not (sham group). Surgeon, patient, and independent outcome assessor were all blinded to the treatment. All patients followed a standard postprocedural rehabilitation program. Independent statistical analysis was performed. Low Back Outcome Score (LBOS), Oswestry Disability Index (ODI), Short Form 36 questionnaire (SF-36), Zung Depression Index (ZDI), and Modified Somatic Perceptions Questionnaire (MSPQ) were measured at baseline and 6 months. Successful outcome was defined as: no neurologic deficit, improvement in LBOS of greater then 7 points, and improvement in SF-36 subsets (physical function and bodily pain) of greater than 1 standard deviation. Baseline demographic data, initial LBOS, ODI, SF-36, ZDI, and MSPQ were similar for both groups. No neurologic deficits occurred. No subject in either arm showed improvement of greater than 7 points in LBOS or greater than 1 standard deviation in the specified domains of the SF-36. Mean ODI was 41.42 at baseline and 39.77 at 6 months for the IDET group, compared with 40.74 at baseline and 41.58 at 6 months for the placebo group. There was no significant change in ZDI or MSPQ scores for either group. The IDET procedure appeared safe with no permanent complications. No subject in either arm met criteria for successful outcome. Further detailed analyses showed no significant change in outcome measures in either group at 6 months. This study demonstrates no significant benefit from IDET over placebo.

Internal Strains in Healthy and Degenerated Lumbar Intervertebral Discs

A biomechanical study investigating the intradiscal mechanics of human lumbar intervertebral discs (IVDs). To assess the relationship between nucleus pulposus migration and intradiscal strains as a function of degeneration. Intradiscal deformation studies have documented the nucleus pulposus migration capabilities during bending but without assessing subsequent intradiscal strains of the anulus fibrosus. Degenerated IVDs show higher anular laxity, hypermobility, and, perhaps, segmental instability. It is unknown if nucleus pulposus migration might be the cause of increased intradiscal anular strains and if such a phenomenon is modulated by IVD degeneration. Eighteen healthy and degenerated IVDs were subjected to compression, extension, flexion, and lateral bending. Craniocaudal radiographs at unloaded and loaded steps documented positions of wires placed within and beads glued to the external surface in the mid-transverse plane. Circumferential and radial strains from the anterior, lateral, and posterolateral regions during load were compared between healthy and degenerated IVDs. The nucleus pulposus migrated to the opposite side of bending regardless of bending direction and significantly more in degenerated IVDs. The highest nucleus pulposus migration was observed during lateral bending. Circumferential tensile strains were significantly higher in the posterolateral regions of degenerative IVDs during all loads. Degeneration significantly increased radial tensile and compressive strains during all bending loads. Increased nucleus pulposus migration in degenerated IVDs may result in increased shifting of the IVD pivot point during bending movements as well as intradiscal anular strains, particularly in the posterolateral anulus. This phenomenon may explain the segmental instability observed in degenerated segments as well as the associated anular tears present in the posterolateral region before IVD failure.

Magnetic Resonance Imaging and Low Back Pain in Adults: A Diagnostic Imaging Study of 40-Year-Old Men and Women

Cross-sectional cohort study of a general population. To investigate "abnormal" lumbar spine magnetic resonance imaging (MRI) findings, and their prevalence and associations with low back pain (LBP). The clinical relevance of various "abnormal" findings in the lumbar spine is unclear. Distinguishing between inevitable age-related findings and degenerative findings with deleterious consequences is a challenge. Lumbar spine MRI was obtained in 412, 40-year-old individuals. Predefined "abnormal" MRI findings were interpreted without any knowledge of patient symptoms. Associations between MRI abnormalities and LBP were calculated using odds ratios. The "overall picture" of each MRI finding was established on the basis of the frequencies, diagnostic values, and the strength and consistency of associations. Most "abnormal" MRI findings were found at the lowest lumbar levels. Irregular nucleus shape and reduced disc height were common (>50% of individuals). Relatively common (25% to 50%) were hypointense disc signal, anular tears, high intensity zones, disc protrusions, endplate changes, zygapophyseal joint degeneration, asymmetry, and foraminal stenosis. Nerve root compromise, Modic changes, central spinal stenosis, and anterolisthesis/retrolisthesis were rare (<25%). Most strongly associated with LBP were Modic changes and anterolisthesis (odds ratios >4). Significantly positive associations with all LBP variables were seen for hypointense disc signals, reduced disc height, and Modic changes. All disc "abnormalities" except protrusion were moderately associated with LBP during the past year. Most degenerative disc "abnormalities" were moderately associated with LBP. The strongest associations were noted for Modic changes and anterolisthesis. Further studies are needed to define clinical relevance.

The Occurrence of Anular Tears and Their Relation to Lifetime Back Pain History: A Cadaveric Study Using Barium Sulfate Discography

The occurrence of anular tears and general disc degeneration of the lumbar spine was studied in relation to the lifetime frequency of back pain. Although anular tears and ruptures are common targets for diagnostic and therapeutic approaches, the relationship between disc findings and back pain has been weak or nonexistent. The data comprised barium sulfate discograms of lumbar spine levels from 157 male cadavers. The extent of "anular tears" and "general disc degeneration" based on posterior-anterior and side views were evaluated separately using a 4-point scale. Lifetime history of back pain occurrence and work were obtained from the families of 86 cadavers. To assess whether the risk of back pain changed with the severity of findings or the level of disc, we applied trend tests and proportional-odds logistic models for occurrence data. In early adulthood, the risk of anular tears was 0.6 to 0.7, whereas at retirement age, tears were practically unavoidable. The risk of full anular tears with barium sulfate leaking ("leaking" tear) was estimated to be 0.10 and 0.35 among the men in the age groups of 20 to 49 and 50 to 59 years, respectively. The risk of "leaking" tears was greatest at the L5-S1 levels. There were less severe degenerative findings associated with sedentary occupation but no differences between driving and physically light and heavy occupations. Overall, the risk of any anular tears and any general degeneration as defined was similar. The frequency of back pain had a highly significant relation to the occurrence of tears (model-based P = 0.0009). With a "leaking" tear, the model-based estimate of the risk of frequent lifetime back pain was 0.42, with an "outer" tear the risk was 0.20, and with no tears or "inner" tears the risk was 0.10 (the observed prevalence was 0). The effect of occupational loading was of borderline significance (P = 0.045). Anular degeneration of the lumbar discs appear earlier and are more clearly related to back pain than previously thought, most probably due to the better sensitivity of the BaSO4 discography method to detect tears.