Asymmetry between the superior and inferior endplates is a risk factor for lumbar disc degeneration

Endplate pathology plays an important role in the development of lumbar disc degeneration. Previous research paid little attention to differences between the superior and inferior endplates as a possible risk factor for disc degeneration. The purpose of this study was to test the hypothesis that asymmetry between the superior and inferior endplates is a risk factor for the development of lumbar disc degeneration. A total of 134 patients with lumbar disc herniation (LDH) and 100 healthy adults (“Controls”) underwent magnetic resonance imaging scans. Each disc was categorized as non‐degenerated (Pfirrmann grades I–II) or degenerated (Pfirrmann grades III–V) and get the following three groups: “Degenerated LDH” discs (n = 145), “Non‐degenerated LDH” discs (n = 525) and “Non‐degenerated Control” discs (n = 500). On mid‐sagittal image, the lumbar endplate morphology could be categorized into three types: Flat, concave, and irregular. Superior and inferior endplates of a given disc were “symmetric” if both were of the same type, and “asymmetric” if they were of different types. The proportion of asymmetric endplates at L4–5 was higher in the “Degenerated LDH” discs group (47%) than in the “Non‐degenerated LDH” discs group (21%) or “Non‐degenerated Control” discs group (7%) (p < 0.05). At L5‐S1 the proportions were 73%, 55%, and 38% (p < 0.05). Asymmetry of superior and inferior endplates in the mid‐sagittal plane is a risk factor for lumbar disc degeneration. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2469–2475, 2018.

     

Discogenic pain in acute nonspecific low-back pain

Acute nonspecific low-back pain is characterized by the sudden onset and severe unendurable low-back pain without radicular pain or neurological deficit in the lower extremities. The study was carried out using 55 patients who visited our hospital for acute nonspecific low-back pain, who exhibited degeneration on T2-weighted MR images, and underwent intradiscal injection of local anesthetics,steroid and contrast medium. Intervertebral disc sites with an obvious enhanced region in the posterior annulus of the disc on enhanced T1-weghted MR images was selected for intradiscal injection. When no enhaced region was detected, the most severely degenerated disc on T2-weighted MR images was selected. Acute nonspecific low-back pain with an improvement rate of 70% or higher 5min after injection was judged to be discogenic. The clinical characteristics and pathogenesis of discogenic acute nonspecific low-back pain were investigated. Forty of the 55 patients (73%) had discogenic acute nonspecific low-back pain. As for the characteristics of patients, the mean age was 37 years, and onset occurred upon casual daily movements in 18 patients (45%). Nineteen patients (48%) had bilateral low-back pain, and 29 patients (73%) had no tenderness in the paravertebral muscles. On plain X-ray radiograms, degeneration of the disc was normal or mild in 36 patients(91%). On the discograms, a radial tear extending to the posterior annulus was noted in all patients, but epidural leakage was seen only in six patients (15%). The degree of disc degeneration on T2-weighted MR images (Gibsons classification) was grade 3 in 30 patients (75%). Gadolinium-DTPA enhanced T1-weighted MR images showed an obvious enhanced region in the posterior annulus of the intervertebral disc in 19 patients (48%). As for the clinical characteristics of discogenic acute nonspecific low-back pain, the relatively young adult patients had no tenderness in the paravertebral muscles, and showed moderately degererated intervertebral discs. The pathogenesis of discogenic acute nonspecific low-back pain is mostly considered to be a re-rupture in an asymptomatic ruputured region in the posterior annulus, repaired by granulation tissue, in a moderately degenerated intervertebral disc with a radial tear.     

Association of incipient disc degeneration and instability in spondylolisthesis

Summary The concurrence of early disc degeneration and abnormal segmental motion in spondylolysis of young low back pain patients (n = 14) was investigated using magnetic resonance imaging (MRI) and flexion-extension radiography. Seven patients with L5 spondylolisthesis had normal discs on MRI and 7 had disc degeneration below the slipped vertebra. The parallel motion, angular mobility and centre of motion were similar in the degenerated discs and in normal discs. The present study shows that in adolescents the motion pattern and hydration of discs associated with spondylolysis and spondylolisthesis are not always abnormal. The early dehydration and degeneration of lumbar discs observed on MRI are not always associated with abnormal mobility of the corresponding motion segment.     

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

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

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

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

A comparison of CT/discography, pain response and radiographic disc height

CT/discograms of 107 low-back patients were classified by annular degeneration, annular disruption, and pain response. These parameters were compared with the heights of the corresponding discs. Disc height correlated significantly with degenerative annular changes. Comparison of the painless and exact reproduction groups at the L5-S1 level showed a significant increase in exact pain reproduction in narrow discs compared with normal discs. Discs demonstrating slight degenerative changes were often painful but narrowing was detected only when degeneration increased to moderate or severe levels. Some severely degenerated discs were painless and only part of the severe group was narrow. Measuring disc height is a poor method for detecting early, painful degeneration changes.     

Pain and disability correlated with disc degeneration via magnetic resonance imaging in scoliosis patients

Prior imaging studies of scoliosis patients attempted to demonstrate a relationship between plain radiographic curve patterns and curve progression and pain, or used magnetic resonance imaging (MRI) to focus on spinal cord abnormalities. Pain in scoliosis patients may differ from nondeformity patients, yet may still be discogenic. The purpose of this study was to assess the possible relationship of degenerative disc findings on MRI to scoliosis patients’ pain. This prospective study enrolled scoliosis and control patients, all of whom had assessment for back pain (visual analog scale) and disability (Oswestry Index) and spinal MRI to identify prevalence and distribution of degenerative disc findings. Specifically, we assessed 60 consecutive pediatric and adult idiopathic scoliosis patients who had progressed to surgical treatment, 60 age- and gender-matched asymptomatic controls, and 172 nondeformity symptomatic degenerative disc disease patients who had progressed to surgical treatment. All subjects had independent analysis of their preoperative MRI for disc degeneration, disc herniation, Schmorl’s nodes, and inflammatory end plate changes. Imaging findings of the scoliosis patients were compared to those from asymptomatic and symptomatic control groups. Our results found that both pediatric and adult scoliosis patients had significantly more pain and disability than did asymptomatic controls (P < 0.001). The adult idiopathic scoliosis patients had pain and disability similar to those of surgical degenerative disc disease control groups. Disc degeneration and herniation (contained) were not related to pain. However, in the pediatric scoliosis patients, those with Schmorl’s nodes often had greater pain than those without (P = 0.01). Adults with painful scoliosis, typically occurring at the apex of the scoliosis or at the lumbosacral junction, had a significantly higher frequency of inflammatory end plate changes on MRI than did controls (P < 0.001). Prior studies have demonstrated a correlation of inflammatory end plate changes to lumbar discogenic pain. In conclusions, scoliosis patients who have progressed to surgical intervention, pediatric patients have varying degrees of pain, and those with Schmorl’s nodes may be at greater risk for pain. Adult scoliosis patients have multifactorial pain of which one component may be related to degeneration of the lower lumbar discs similar to that in nondeformity patients. Additionally, adult scoliosis patients may have MRI findings consistent with discogenic pain at the apex of their curvature, most commonly at the proximal lumbar levels.     

Disc deterioration in low-back syndromes. A prospective, multi-center CT/discography study

Disc deterioration and pain provocation in different low-back pain syndromes was studied using computed tomography (CT) discography. Data were prospectively collected for 300 patients (816 discs). Patients were classified by their pre-discography diagnosis of disc herniation (DH), degenerated disc (DD), lumbar syndrome (LS), lumbar radicular syndrome (LRS), or other. The CT/discograms were classified by discographic pain response, the amount of degeneration and annular disruption. Eighty-two percent of DH patients, 80% of DD, 56% of LS, and 59% of LRS patients had both positive discographic pain provocation and moderate or severe disc deterioration. The study indicates that intradiscal pathology plays a major role in nonspecific low-back pain syndromes.     

The value of magnetic resonance imaging of the lumbar spine to predict low-back pain in asymptomatic subjects : a seven-year follow-up study

BACKGROUND: In 1989, a group of sixty-seven asymptomatic individuals with no history of back pain underwent magnetic resonance imaging of the lumbar spine. Twenty-one subjects (31%) had an identifiable abnormality of a disc or of the spinal canal. In the current study, we investigated whether the findings on the scans of the lumbar spine that had been made in 1989 predicted the development of low-back pain in these asymptomatic subjects. METHODS: A questionnaire concerning the development and duration of low-back pain over a seven-year period was sent to the sixty-seven asymptomatic individuals from the 1989 study. A total of fifty subjects completed and returned the questionnaire. A repeat magnetic resonance scan was made for thirty-one of these subjects. Two neuroradiologists and one orthopaedic spine surgeon interpreted the original and repeat scans in a blinded fashion, independent of clinical information. At each disc level, any radiographic abnormality, including bulging or degeneration of the disc, was identified. Radiographic progression was defined as increasing severity of an abnormality at a specific disc level or the involvement of additional levels. RESULTS: Of the fifty subjects who returned the questionnaire, twenty-nine (58%) had no back pain. Low-back pain developed in twenty-one subjects during the seven-year study period. The 1989 scans of these subjects demonstrated normal findings in twelve, a herniated disc in five, stenosis in three, and moderate disc degeneration in one. Eight individuals had radiating leg pain; four of them had had normal findings on the original scans, two had had spinal stenosis, one had had a disc protrusion, and one had had a disc extrusion. In general, repeat magnetic resonance imaging scans revealed a greater frequency of disc herniation, bulging, degeneration, and spinal stenosis than did the original scans. CONCLUSIONS: The findings on magnetic resonance scans were not predictive of the development or duration of low-back pain. Individuals with the longest duration of low-back pain did not have the greatest degree of anatomical abnormality on the original, 1989 scans. Clinical correlation is essential to determine the importance of abnormalities on magnetic resonance images.     

Degeneration of non-fused segments after floating lumbar fusion

Degeneration of the disc or discs between two fused spinal segments has been termed "floating disc disease". The purpose of this retrospective study was to show the radiological evolution of the floating disc(s) and the relationship between floating disc degeneration and segmental lordosis, lumbar lordosis and pelvic incidence. Twenty patients, with a mean age of 49.9 years, with symptomatic lumbar degenerative disc disease or low grade spondylolisthesis, who failed non-operative treatment and underwent fusion of 2 or more noncontiguous spinal segments, were included in this study. The radiographs of the floating discs were graded with the modified Gore System. The mean follow-up was 4.2 years. Forty-seven levels were fused and 27 floating discs were studied (13 single, 7 double). Five out of 27 floating discs (18%), in 4 patients, progressively degenerated. None of the floating discs degenerated more than two radiographic grades and none needed additional surgery. Postoperatively, 3 out of 5 degenerated floating discs had decreased segmental lordosis, while the other two had no change; this difference was not significant (p = 0.08). Neither was there any significant correlation between floating disc degeneration and lumbar lordosis L1-S1 (p > 0.10) or pelvic incidence (p > 0.10). This study shows that the effect of floating fusion on floating discs is the same as the effect of a contiguous fusion on adjacent discs.     

Magnetic resonance study of disc degeneration in young low-back pain patients

The correlation of roentgenographic findings, clinical history, and incipient disc degeneration (DD), diagnosed with magnetic resonance imaging, was analyzed in young patients with low-back pain (LBP). One or more lumbar discs were abnormal in 57% of the 20-year-old LBP patients (n = 75) and in 35% of the asymptomatic controls (n = 34) in MRI. Narrowed disc spaces and alterations attributed to lumbar Scheuermann's disease, shown on the radiographs, were always associated with DD in MRI. Such a strong relationship was not observed with transitional vertebrae, spondylolisthesis, spina bifida, or postural abnormalities. However, an increased weight, a positive straight leg raising test, and a reduced lumbar mobility was consistent with an increase in frequency of DD. Magnetic resonance imaging is a safe and sensitive method for studying the presence and etiologic factors of DD.     

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

One hundred and one disc levels in 36 patients with low-back pain were studied with magnetic resonance imaging (MRI) (T2-weighted) sagittal images and conventional roentgenographic discography to detect early disc degeneration. Thirty-nine discs also were evaluated after discography with roentgenographic CT MRI findings were compared with discography results. MRI was 99% accurate in predicting normality or abnormality as determined by discography. Changes in disc signal on MRI accurately reflected the presence or absence of degenerative changes seen on discography in patients with low-back pain. Clinically, MRI is a useful technique for detecting early disc degeneration and for assessing the affected disc level and adjacent levels in patients with low-back pain and spondylolithesis.     

Mitochondrial bioenergetics,mass, and morphology are altered in cells of the degenerating human annulus

Back pain and intervertebral disc degeneration have a growing socioeconomic healthcare impact. Information on mitochondrial function in human intervertebral disc cells, however, is surprisingly sparse. We assessed mitochondrial bioenergetics, mass, and ultrastructure in annulus cells cultured from human discs of varying degenerative stages. Citrate synthase activity (reflecting mitochondrial mass) declined significantly with increasing Thompson grade (p < 0.0001). Both mitochondrial (p = 0.009) and non‐mitochondrial (p = 0.0029) respiration showed significant changes with increasing stages of disc degeneration. No significant relationships were found for the association of respiration data with herniated or non‐herniated status, or with subject age. Examination of mitochondrial ultrastructure in cultured annulus cells revealed unusual features which included mitochondrial inclusion bodies, poorly defined cristae and dark staining. Findings reported here are novel and document biochemical, metabolic, and morphologic abnormalities in mitochondria in cells from more degenerated annulus cells. Data suggest that the disc degenerative, not age, is a major factor associated with mitochondrial impairment, and also implicate oxidative stress, driven by mitochondrial dysfunction, as a major component within the degenerating disc. Findings have relevance to advancements in cell‐based therapies to treat disc degeneration. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1270–1275, 2013     

Model of Disc Degeneration in Rat Tail Induced Through a Vascular Isolation of Vertebral Endplates

Back pain is a major health problem. The degenerative cascade of the spine begins in the intervertebral disc, due to an impairment in the blood supply through the vertebral endplates. Our objective was to develop a novel disc degeneration model based on these premises, akin to the process in humans, in contrast to other proposed models (puncture, enzyme injection, aberrant loads,…) Material and methods: 37 Sprague-Dawley rats, 2 arms: (a) histological (n = 17, one died), en- bloc sections, Van Gieson staining, (Nisimura-Mochida criteria) and also collagen VI staining (tissue oxidative stress), four animals were euthanized every 2 weeks (2-8); and (b) imaging (n = 20, six wound sloughs), MRI 9.4 Tesla protocol, sequential disc volumetric analysis (24 h-8 weeks) in all animals. Disc degeneration was induced by means of vascular isolation of tail discs endplates either from one side or both. Results: Isolation from both sides caused a progressive degeneration of the disc (p < 0.001 vs. controls), bigger than isolation from one side (p < 0.01 vs. both sides and p < 0.05 vs. controls), as rated by volumetric reduction; furthermore, tissue structural changes (Nisimura-Mochida) and collagen VI deposition confirmed these results. Conclusion: the model here described represents a novel and translational tool that reproduces the intervertebral disc degeneration in a similar way to that taking place in human beings.     

Lack of association between lumbar disc degeneration and osteophyte formation in elderly japanese women with back pain

Our study was designed to assess the contributions of the physical and constitutional factors to osteophyte formation, disc degeneration, and bone mineral density (BMD) in lumbar vertebrae of elderly postmenopausal women. A total of 126 Japanese women with back pain, aged over 60 years, were invited to participate in the study. Then 80 subjects with a full set of data for physical examinations, radiographs, MRI, and DXA were examined. TaqI polymorphism of vitamin D receptor (VDR) gene was examined in 60 subjects. Prevalence rates of osteophytes (on radiographs) and disc degeneration (on MRI) were 61 and 68%, respectively. Body weight and BMI correlated significantly with anteroposterior (AP) and lateral (LAT) BMD (r = 0.354 for weight, r = 0.347 for BMI) and mean osteophyte area (r = 0.557 for weight, r = 0.486 for BMI), and body weight also correlated with number of discs with osteophytes. However, these did not correlate with the disc area or the number of degenerated discs. Stepwise regression analysis revealed that body weight and LAT-BMD values independently related to the osteophyte area. Disc area (r = 0.386 for AP view) and osteophyte area (r = 0.384 for AP view) significantly correlated with BMD. However, disc area and osteophyte area did not correlate with each other (r = 0.056). The proportion of degenerated discs was higher in the lower lumbar discs, but not the proportion of discs with osteophytes. Frequencies of T and t alleles of VDR did not correlate with disc degeneration, osteophyte formation, or osteoporosis. Our data showed that increases in osteophyte formation and BMD in the lumbar vertebrae are influenced by body weight and BMI, but did not correlate with disc area, which correlated inversely with BMD. Disc degeneration and osteophyte formation seem to represent two different factors that affect lumbar spine in elderly women.     

Comparative roentgenographic study of the asymptomatic and symptomatic lumbar spine.

A comparative roentgenographic study was carried out on 217 asymptomatic patients between forty and seventy years old and 387 symptomatic patients in the same age range. Spondylosis (osteophyte formation) did not appear to have any direct relationship to low-back pain. Degenerative disc disease appeared to be a major cause of low-back pain. Spondylolysis and spondylolisthesis occurred more frequently in the symptomatic than in the asymptomatic patients. Routine roentgenograms of the lumbosacral spine were useful in evaluating patients seen for treatment of low-back pain.     

Increased cell senescence is associated with decreased cell proliferation in vivo in the degenerating human annulus

Background contextDuring disc degeneration, there is a well-recognized loss of cells. This puts the remaining cell population at high risk for any further decrease in cell function or cell numbers. Cell senescence has recently been shown to be present in the aging/degenerating human disc. Senescent cell are viable, metabolically active, persist, and accumulate over time, but cannot divide. Little is known about the relationship between renewal of the disc cell population via cell proliferation and disc cell senescence.PurposeTo determine the percentage of senescent cells and proliferating cells in the human annulus in vivo.Study design/settingHuman annulus specimens were obtained from surgical subjects and control donors in a study approved by the authors' Human Subjects Institutional Review Board.Patient sampleOne Thompson Grade I disc, 4 Grade II discs, 9 Grade III discs, and 12 Grade IV discs were studied.Outcome measuresThe percentages of senescent cells and the percentage of proliferating cells.MethodsImmunohistochemistry was used to detect senescent cells using an antisenescence-associated beta-galactosidase antibody, and an antiproliferation antibody (Ki67). An average of 410 cells/specimens was counted to determine the percent senescence, and an average of 229 cells was counted to determine the percent proliferation.ResultsCell proliferation was low in both surgical and control normal donor annulus tissue (4.09%+1.77 (26), mean+SD (n)). There was no significant difference in the percentage of proliferating cells for more degenerate discs versus healthier discs (4.7%+1.6 (21) for Grades III and IV vs. 5.3%+1.9 (5) for Grades I and II). More degenerated Grades III and IV discs contained significantly greater percentages of senescent annulus cells than did the healthier Grades I and II discs (44.4%+20.0 (21) vs. 18.8%+11.0 (5), respectively; p=.011). A significant negative correlation was present between the percentage of senescent cells versus the percentage of proliferating cells, r=?0.013, p=.013. No correlation was present between age and the percentage of senescent cells or age and the percentage of proliferating cells.ConclusionsBecause senescent cells cannot divide, senescence may reduce the disc's ability to generate new cells to replace cells lost to necrosis or apoptosis. Senescent cells also accumulate in the disc over time, such that their metabolic patterns may contribute to the pathologic changes seen in degenerating discs. Novel data presented here show a significant negative correlation between the percentage of senescent cells and the percentage of proliferating cells during disc degeneration. Molecular work is underway in our lab to help us determine whether senescent cells in the disc secrete factors that can result in decreased proliferation in neighboring cells.     

Nucleus pulposus degeneration alters properties of resident progenitor cells

Background contextThe intervertebral disc (IVD) possesses a minimal capability for self-repair and regeneration. Changes in the differentiation of resident progenitor cells can represent diminished tissue regeneration and a loss of homeostasis. We previously showed that progenitor cells reside in the nucleus pulposus (NP). The effect of the degenerative process on these cells remains unclear.PurposeWe sought to explore the effect of IVD degeneration on the abundance of resident progenitor cells in the NP, their differentiation potential, and their ability to give rise to NP-like cells. We hypothesize that disc degeneration affects those properties.Study designNucleus pulposus cells derived from healthy and degenerated discs were methodically compared for proliferation, differentiation potential, and ability to generate NP-like cells.MethodsIntervertebral disc degeneration was induced in 10 skeletally, mature mini pigs using annular injury approach. Degeneration was induced in three target discs, whereas intact adjacent discs served as controls. The disc degeneration was monitored using magnetic resonance imaging for 6 to 8 weeks. After there was a clear evidence of degeneration, we isolated and compared cells from degenerated discs (D-NP cells [NP-derived cells from porcine degenerated discs]) with cells isolated from healthy discs (H-NP cells) obtained from the same animal.ResultsThe comparison showed that D-NP cells had a significantly higher colony-forming unit rate and a higher proliferation rate in vitro. Our data also indicate that although both cell types are able to differentiate into mesenchymal lineages, H-NP cells exhibit significantly greater differentiation toward the chondrogenic lineage and NP-like cells than D-NP cells, displaying greater production of glycosaminoglycans and higher gene expression of aggrecan and collagen IIa.ConclusionsBased on these findings, we conclude that IVD degeneration has a meaningful effect on the cells in the NP. D-NP cells clearly go through the regenerative process; however, this process is not powerful enough to facilitate full regeneration of the disc and reverse the degenerative course. These findings facilitate deeper understanding of the IVD degeneration process and trigger further studies that will contribute to development of novel therapies for IVD degeneration.     

Part 2: quantitative proton t2 and sodium magnetic resonance imaging to assess intervertebral disc degeneration in a rabbit model

STUDY DESIGN.: Comparison of sodium concentration ([Na]) and proton T2 relaxation time between normal and degenerated discs in a rabbit model. OBJECTIVE.: The purpose of this article was to evaluate quantitative [Na] and T2 characteristics of discs associated with degenerative changes. SUMMARY OF BACKGROUND DATA.: Intervertebral disc degeneration is a common chronic condition that may lead to back pain, limited activity, and disability. Noninvasive imaging method to detect early intervertebral disc degeneration is vital to follow disease progression and guide clinical treatment and management. METHODS.: Dual-tuned magnetic resonance imaging of rabbit discs was performed using 3T. Thirteen rabbits were included in the study; 6 control rabbits (24 normal discs) and 7 rabbits with annular puncture-induced disc degeneration (9 degenerated discs, 19 intact internal-control discs). Dual-tuned magnetic resonance imaging of discs was performed at baseline and 12-week poststab. [Na] and T2 were measured and compared among 3 groups of discs. RESULTS.: The mean [Na] were 274.8 ± 40.2 mM for the normal discs, 247.2 ± 27.7 mM for the internal-control discs, and 190.6 ± 19.1 mM for the degenerated discs. The corresponding T2 for 3 groups were 97.1 ± 12.1 ms, 93.7 ± 11.9 ms, and 79.0 ± 9.1 ms, respectively. The [Na] is highly correlated with the T2 in the degenerated discs (r = 0.90, P < 0.01). The mean percent decreases from the normal to degenerated discs were in 30.6% in [Na] and 18.6% in T2, whereas those from the internal-control to degenerated discs were 22.9% in [Na] and 15.6% in T2. CONCLUSION.: Although both [Na] and T2 changes in discs were associated with the disc-punctured rabbits, greater change in [Na] is observed at 12-week poststab compared with T2 change. Because T2 and [Na] reflect different disc properties, performing both imaging under same condition will be helpful in the evaluation of disc degeneration.     

Patterns of lumbar disc degeneration are different in degenerative disc disease and disc prolapse magnetic resonance imaging analysis of 224 patients

Background contextExisting research on lumbar disc degeneration has remained inconclusive regarding its etiology, pathogenesis, symptomatology, prevention, and management. Degenerative disc disease (DDD) and disc prolapse (DP) are common diseases affecting the lumbar discs. Although they manifest clinically differently, existing studies on disc degeneration have included patients with both these features, leading to wide variations in observations. The possible relationship or disaffect between DDD and DP is not fully evaluated.PurposeTo analyze the patterns of lumbar disc degeneration in patients with chronic back pain and DDD and those with acute DP.Study designProspective, magnetic resonance imaging–based radiological study.MethodsTwo groups of patients (aged 20–50 years) were prospectively studied. Group 1 included patients requiring a single level microdiscectomy for acute DP. Group 2 included patients with chronic low back pain and DDD. Discs were assessed by magnetic resonance imaging through Pfirmann grading, Schmorl nodes, Modic changes, and the total end-plate damage score for all the five lumbar discs.ResultsGroup 1 (DP) had 91 patients and group 2 (DDD) had 133 patients. DP and DDD patients differed significantly in the number, extent, and severity of degeneration. DDD patients had a significantly higher number of degenerated discs than DP patients (p<.000). The incidence of multilevel and pan-lumbar degeneration was also significantly higher in DDD group. The pattern of degeneration also differed in both the groups. DDD patients had predominant upper lumbar involvement, whereas DP patients had mainly lower lumbar degeneration. Modic changes were more common in DP patients, especially at the prolapsed level. Modic changes were present in 37% of prolapsed levels compared with 9.9% of normal discs (p<.00). The total end-plate damage score had a positive correlation with disc degeneration in both the groups. Further the mean total end-plate damage score at prolapsed level was also significantly higher.ConclusionThe results suggest that patients with disc prolapse, and those with back pain with DDD are clinically and radiologically different groups of patients with varying patterns, severity, and extent of disc degeneration. This is the first study in literature to compare and identify significant differences in these two commonly encountered patient groups. In patients with single-level DP, the majority of the other discs are nondegenerate, the lower lumbar spine is predominantly involved and the end-plate damage is higher. Patients with back pain and DDD have larger number of degenerate discs, early multilevel degeneration, and predominant upper lumbar degeneration. The knowledge that these two groups of patients are different clinically and radiologically is critical for our improved understanding of the disease and for future studies on disc degeneration and disc prolapse.