Presence and extent of severe facet joint osteoarthritis are associated with back pain in older adults

Nociceptive, neuropathic, or nociplastic low back pain? The low back pain phenotyping (BACPAP) consortium's international and multidisciplinary consensus recommendations

The potential to classify low back pain as being characterised by dominant nociceptive, neuropathic, or nociplastic mechanisms is a clinically relevant issue. Preliminary evidence suggests that these low back pain phenotypes might respond differently to treatments; however, more research must be done before making specific recommendations. Accordingly, the low back pain phenotyping (BACPAP) consortium was established as a group of 36 clinicians and researchers from 13 countries (five continents) and 29 institutions, to apply a modified Nominal Group Technique methodology to develop international and multidisciplinary consensus recommendations to provide guidance for identifying the dominant pain phenotype in patients with low back pain, and potentially adapt pain management strategies. The BACPAP consortium's recommendations are also intended to provide direction for future clinical research by building on the established clinical criteria for neuropathic and nociplastic pain. The BACPAP consortium's consensus recommendations are a necessary early step in the process to determine if personalised pain medicine based on pain phenotypes is feasible for low back pain management. Therefore, these recommendations are not ready to be implemented in clinical practice until additional evidence is generated that is specific to these low back pain phenotypes.

Systematic review of computed tomography parameters used for the assessment of subchondral bone in osteoarthritis

OBJECTIVE

To systematically review the published parameters for the assessment of subchondral bone in human osteoarthritis (OA) using computed tomography (CT) and gain an overview of current practices and standards.

DESIGN

A literature search of Medline, Embase and Cochrane Library databases was performed with search strategies tailored to each database (search from 2010 to January 2023). The search results were screened independently by two reviewers against pre-determined inclusion and exclusion criteria. Studies were deemed eligible if conducted in vivo/ex vivo in human adults (>18 years) using any type of CT to assess subchondral bone in OA. Extracted data from eligible studies were compiled in a qualitative summary and formal narrative synthesis.

RESULTS

This analysis included 202 studies. Four groups of CT modalities were identified to have been used for subchondral bone assessment in OA across nine anatomical locations. Subchondral bone parameters measuring similar features of OA were combined in six categories: (i) microstructure, (ii) bone adaptation, (iii) gross morphology (iv) mineralisation, (v) joint space, and (vi) mechanical properties.

CONCLUSIONS

Clinically meaningful parameter categories were identified as well as categories with the potential to become relevant in the clinical field. Furthermore, we stress the importance of quantification of parameters to improve their sensitivity and reliability for the evaluation of OA disease progression and the need for standardised measurement methods to improve their clinical value.

Mechanical crosstalk between the intervertebral disc, facet joints, and vertebral endplate following acute disc injury in a rabbit model

Background

Vertebral endplate sclerosis and facet osteoarthritis have been documented in animals and humans. However, it is unclear how these adjacent pathologies engage in crosstalk with the intervertebral disc. This study sought to elucidate this crosstalk by assessing each compartment individually in response to acute disc injury.

Methods

Eleven New Zealand White rabbits underwent annular disc puncture using a 16G or 21G needle. At 4 and 10 weeks, individual compartments of the motion segment were analyzed. Discs underwent T 1 relaxation mapping with MRI contrast agent gadodiamide as well T 2 mapping. Both discs and facets underwent mechanical testing via vertebra-disc-vertebra tension-compression creep testing and indentation testing, respectively. Endplate bone density was quantified via μCT. Discs and facets were sectioned and stained for histology scoring.

Results

Intervertebral discs became more degenerative with increasing needle diameter and time post-puncture. Bone density also increased in endplates adjacent to both 21G and 16G punctured discs leading to reduced gadodiamide transport at 10 weeks. The facet joints, however, did not follow this same trend. Facets adjacent to 16G punctured discs were less degenerative than facets adjacent to 21G punctured discs at 10 weeks. 16G facets were more degenerative at 4 weeks than at 10, suggesting the cartilage had recovered. The formation of severe disc osteophytes in 16G punctured discs between 4 and 10 weeks likely offloaded the facet cartilage, leading to the recovery observed.

Conclusions

Overall, this study supports that degeneration spans the whole spinal motion segment following disc injury. Vertebral endplate thickening occurred in response to disc injury, which limited the diffusion of small molecules into the disc. This work also suggests that altered disc mechanics can induce facet degeneration, and that extreme bony remodeling adjacent to the disc may promote facet cartilage recovery through offloading of the articular cartilage.

Low back pain and osteoarthritis pain: a perspective of estrogen

Low back pain (LBP) is the world's leading cause of disability and is increasing in prevalence more rapidly than any other pain condition. Intervertebral disc (IVD) degeneration and facet joint osteoarthritis (FJOA) are two common causes of LBP, and both occur more frequently in elderly women than in other populations. Moreover, osteoarthritis (OA) and OA pain, regardless of the joint, are experienced by up to twice as many women as men, and this difference is amplified during menopause. Changes in estrogen may be an important contributor to these pain states. Receptors for estrogen have been found within IVD tissue and nearby joints, highlighting the potential roles of estrogen within and surrounding the IVDs and joints. In addition, estrogen supplementation has been shown to be effective at ameliorating IVD degeneration and OA progression, indicating its potential use as a therapeutic agent for people with LBP and OA pain. This review comprehensively examines the relationship between estrogen and these pain conditions by summarizing recent preclinical and clinical findings. The potential molecular mechanisms by which estrogen may relieve LBP associated with IVD degeneration and FJOA and OA pain are discussed.

Facet Joint Syndrome: Pathophysiology, Diagnosis, and Treatment

Facet joint osteoarthritis (OA) is the most frequent form of facet joint syndrome. Medical history, referred pain patterns, physical examination, and diagnostic imaging studies (standard radiographs, magnetic resonance imaging, computed tomography and single-photon emission computed tomography) may suggest but not confirm lumbar facet joint (LFJ) syndrome as a source of low back pain (LBP). However, the diagnosis and treatment of facet joint syndrome is still controversial and needs further study. It is widely acknowledged that block with local anesthetic is perhaps the most effective method to establish a diagnosis of pain from LFJ. Particularly, there are different rates of success among different populations selected for diagnostic block with various positive criteria. Currently, in addition to conservative treatments for pain such as painkillers, functional exercises, and massage, there are many other methods, including block, denervation of the nerves that innervate the joints by radiofrequency, freezing or endoscopy, and injections. Due to the limited duration of pain relief from neurolysis of medial branch, many scholars have recently turned their targets to dorsal roots and LFJ capsules. Therefore, we reviewed the latest research progress of facet joint syndrome from diagnosis to treatment.

Biochemical and biomechanical characterization of the cervical, thoracic, and lumbar facet joint cartilage in the Yucatan minipig

Facet joint arthrosis causes pain in approximately 7 % of the U.S. population, but current treatments are palliative. The objective of this study was to elucidate structure-function relationships and aid in the development of future treatments for the facet joint. This study characterized the articular surfaces of cervical, thoracic, and lumbar facet cartilage from skeletally mature (18-24 mo) Yucatan minipigs. The minipig was selected as the animal model because it is recognized by the U.S. Food and Drug Administration (FDA) and the American Society for Testing and Materials (ASTM) as a translationally relevant model for spine-related indications. It was found that the thoracic facets had a ∼2 times higher aspect ratio than lumbar and cervical facets. Lumbar facets had 6.9-9.6 times higher % depth than the cervical and thoracic facets. Aggregate modulus values ranged from 135 to 262 kPa, much lower than reported aggregate modulus in the human knee (reported to be 530-701 kPa). The tensile Young's modulus values ranged from 6.7 to 20.3 MPa, with the lumbar superior facet being 304 % and 286 % higher than the cervical inferior and thoracic superior facets, respectively. Moreover, 3D reconstructions of entire vertebral segments were generated. The results of this study imply that structure-function relationships in the facet cartilage are different from other joint cartilages because biochemical properties are analogous to other articular cartilage sources whereas mechanical properties are not. By providing functional properties and a 3D database of minipig facet geometries, this work may supply design criteria for future facet tissue engineering efforts.

Quantitative Radiological Characteristics of the Facet Joints in Patients with Lumbar Foraminal Stenosis

Purpose

This study aimed to evaluate the degeneration patterns of the facet joints (FJs) in patients with lumbar foraminal stenosis (LFS) and investigate the correlation between quantitative parameters and FJ osteoarthritis (FJ OA).

Patients and Methods

A total of 171 patients with LFS at the L4/5 level and 146 control patients were enrolled in this study. The severity of FJ OA was graded according to the Weishaupt classification. The FJ orientation, FJ tropism, superior articular process cross-sectional area (SAPA), and FJ area were measured at the L3/4, L4/5, and L5/S1 spinal levels. Associations among the parameters were assessed using Pearson's correlation coefficients. Independent sample t-tests and Pearson's chi-square tests were used for univariate analyses. The association between LFS and the quantitative parameters was also analyzed using multivariate logistic regression models adjusted for age, gender, and body mass index.

Results

Patients with LFS had more sagittal FJ orientation (37.9 vs 45.0, p < 0.001), more FJ tropism (5.6 vs 3.8, p < 0.001), larger SAPA (129.0 vs 97.8, p < 0.001), and less FJ area (21.7 vs 23.3, p = 0.016). Logistic regression analysis showed that LFS was significantly associated with FJ tropism (odds ratio [OR]: 1.153; p = 0.003) and SAPA (OR: 1.113; p < 0.001). The SAPA showed the largest area under the curve (0.908, 95% confidence interval: 0.875-0.942) for the diagnosis of LFS. The optimal cutoff value was 114.75 mm2 with 85.4% sensitivity and 87.0% specificity. Additionally, a significant correlation was observed between FJ OA and SAPA and FJ area at each studied spinal level.

Conclusion

This study confirmed that LFS is significantly associated with FJ hypertrophy and tropism. FJ hypertrophy and joint space narrowing correlated with the severity of FJ OA. These results are helpful in understanding the morphology and pathology of FJs.

PET/CT imaging of spinal inflammation and microcalcification in patients with low back pain: A pilot study on the quantification by artificial intelligence-based segmentation

Background

Current imaging modalities are often incapable of identifying nociceptive sources of low back pain (LBP). We aimed to characterize these by means of positron emission tomography/computed tomography (PET/CT) of the lumbar spine region applying tracers ¹⁸F‐fluorodeoxyglucose (FDG) and ¹⁸F‐sodium fluoride (NaF) targeting inflammation and active microcalcification, respectively.

Methods

Using artificial intelligence (AI)‐based quantification, we compared PET findings in two sex‐ and age‐matched groups, a case group of seven males and five females, mean age 45 ± 14 years, with ongoing LBP and a similar control group of 12 pain‐free individuals. PET/CT scans were segmented into three distinct volumes of interest (VOIs): lumbar vertebral bodies, facet joints and intervertebral discs. Maximum, mean and total standardized uptake values (SUVmax, SUVmean and SUVtotal) for FDG and NaF uptake in the 3 VOIs were measured and compared between groups. Holm–Bonferroni correction was applied to adjust for multiple testing.

Results

FDG uptake was slightly higher in most locations of the LBP group including higher SUVmean in the intervertebral discs (0.96 ± 0.34 vs. 0.69 ± 0.15). All NaF uptake values were higher in cases, including higher SUVmax in the intervertebral discs (11.63 ± 3.29 vs. 9.45 ± 1.32) and facet joints (14.98 ± 6.55 vs. 10.60 ± 2.97).

Conclusion

Observed intergroup differences suggest acute inflammation and microcalcification as possible nociceptive causes of LBP. AI‐based quantification of relevant lumbar VOIs in PET/CT scans of LBP patients and controls appears to be feasible. These promising, early findings warrant further investigation and confirmation.

Prevalence, Incidence, and Factors Associated With Non-Specific Chronic Low Back Pain in Community-Dwelling Older Adults Aged 60 Years and Older: A Systematic Review and Meta-Analysis

Chronic low back pain (CLBP) is common among older adults. This systematic review aimed to summarize: (1) the prevalence and incidence of CLBP in older adults, and (2) demographic, psychological, and clinical factors positively/negatively associated with prevalence/incidence of CLBP among older adults. Four databases were searched to identify relevant publications. Ten studies (31,080 older adults) were included after being screened by 5 independent reviewers using predetermined criteria. The methodological quality of these studies was evaluated by standardized tools. The quality of evidence for all factors were appraised by modified GRADE for cohort studies. Twenty-eight and 1 factors were associated with a higher prevalence and a lower 5-year cumulative incidence of CLBP, respectively. No prognostic factor was identified. There was very limited to limited evidence that females, obesity, anxiety, depression, mental disorders, self-expectation of recovery, self-perceived health status, lifestyle (smoking, daily fluoride consumption), previous falls or lower body injury, retirement/disability due to ill health, family history of body pain, comorbidity (knee osteoarthritis, or chronic obstructive pulmonary disease with/without hypertension), weak abdominal muscles, leg pain, leg pain intensity, widespread pain, pain interference on functioning, use of pain medication, occupational exposure (driving for >20 years, or jobs involving bending/twisting for >10 years), disc space narrowing and severe facet osteoarthritis were significantly related to a higher prevalence of CLBP in older adults. However, very limited evidence suggested that intermediate level of leisure-time physical activity was associated with a lower prevalence of CLBP in older adults. Given the aging population and limited information regarding risk factors for CLBP in older adults, future high-quality prospective studies should identify relevant risk factors to help develop proper preventive and treatment strategies. PERSPECTIVE: Despite the high prevalence of non-specific chronic low back pain among older adults, there is only very limited to limited evidence regarding factors associated with a higher prevalence of chronic low back pain in this population. Given the aging population, high-quality prospective studies are warranted to address this gap.

Intra-articular collagenase in the spinal facet joint induces pain, DRG neuron dysregulation and increased MMP-1 absent evidence of joint destruction

Degeneration is a hallmark of painful joint disease and is mediated by many proteases that degrade joint tissues, including collagenases. We hypothesized that purified bacterial collagenase would initiate nociceptive cascades in the joint by degrading the capsular ligament's matrix and activating innervating pain fibers. Intra-articular collagenase in the rat facet joint was investigated for its effects on behavioral sensitivity, joint degeneration, and nociceptive pathways in the peripheral and central nervous systems. In parallel, a co-culture collagen gel model of the ligament was used to evaluate effects of collagenase on microscale changes to the collagen fibers and embedded neurons. Collagenase induced sensitivity within one day, lasting for 3 weeks (p < 0.001) but did not alter ligament structure, cartilage health, or chondrocyte homeostasis. Yet, nociceptive mediators were increased in the periphery (substance P, pERK, and MMP-1; p ≤ 0.039) and spinal cord (substance P and MMP-1; p ≤ 0.041). The collagen loss (p = 0.008) induced by exposing co-cultures to collagenase was accompanied by altered neuronal activity (p = 0.002) and elevated neuronal MMP-1 (p < 0.001), suggesting microscale collagen degradation mediates sensitivity in vivo. The induction of sustained sensitivity and nociception without joint damage may explain the clinical disconnect in which symptomatic joint pain patients present without radiographic evidence of joint destruction.

Characterization of the Subchondral Bone and Pain Behavior Changes in a Novel Bipedal Standing Mouse Model of Facet Joint Osteoarthritis

Background

The subchondral bone parallels with the progression of osteoarthritis (OA). However, the biomechanical properties and histopathological changes of subchondral bone changes in the lumbar facet joint (LFJ) after long-term axial loading on the spine have not been explored. In this study, we aimed to investigate the subchondral bone histopathological changes that occur in the LFJ and pain behaviors in a novel bipedal standing mouse model.

Methods

Sixteen 8-week-old male C57BL/6 mice were randomly assigned into bipedal standing and control groups. A finite element stimulate model based on the micro-CT data was generated to simulate the von Mises stress distribution on the LFJ during different positions. The spine pain behaviors tests were analysis. In addition, the change in the subchondral bone of the LFJ was assessed by histological and immunohistochemistry staining.

Results

The computerized simulation of the von Mises stress distribution in the superior articular process of LFJ at the spine level 5 in the lying position increased and reached a maximum value at the bipedal standing posture. The spine pain behavior test revealed that the threshold of pressure tolerance decreased significantly in bipedal groups relative to control groups, whereas the mechanical hyperalgesia of the hind paw increased significantly in bipedal groups relative to control groups. The axial load accelerates LFJ degeneration with increased histological scores in bipedal groups. The expression of type II collagen and aggrecan (ACAN) was significantly decreased in the bipedal groups compared with the control groups, whereas the expression of MMP13 was increased. Compared with the control groups, the osteoclast activity was activated with higher TRAP-positive staining and associated with increased CD-31-positive vessels and GCRP-positive nerve ending expression in the subchondral bone of LFJ.

Conclusion

Collectively, long-term axial loading induces the development of spine hyperalgesia in mice associate with increased osteoclast activity and aberrant angiogenesis and nerve invasion into the subchondral bone of LFJ that stimulates the natural pathological change in human LFJ OA. These results indicate that aberrant bone remodeling associate with aberrant nerve innervation in the subchondral bone has a potential as a therapeutic target in LFJ OA pain.

Facet joint syndrome treated with interventional procedures: a review article with an update on the current evidence and practice

Background:

Facet Joint Syndrome (FJS) is a common progressive disease affecting small joints of the spine and can have painful symptoms. When conservative treatment measures fail, there are a wide range of interventional procedures that can be used. Varied results have been obtained with different procedures, and standardized indications and guidelines are unclear. The authors aimed to review the most current evidence on indications, utilization of interventional procedures, results, and complication risks for the treatment of FJS.

Methods:

Customized structured electronic searches were performed in PubMed and Cochrane databases. Meta-analyses, randomized controlled trials (RCT), and systematic reviews on FJS treated with interventional minimally invasive procedures published from 1st of January 2015 to 29th of February 2020 were included. We initially selected 320 studies, and 25 studies (two meta-analyses, six systematic reviews, and 17 RCT) were selected according to inclusion and exclusion criteria.

Results:

A certain amount of improvement of pain was reported in 100% of the patients, with no significant complications reported. Most studies showed efficacy of all interventional procedures at all levels of evidence, without providing definitive data on indications and superiority of one procedure over others.

Conclusions:

The authors suggest a standardized stepladder approach to the management of FJS, with conservative measures initially and interventional procedures if those measures fail. All procedures were reported to be safe and efficient when clinically indicated and properly performed. Further studies with appropriate methodology are needed.

Level of Evidence:

Level IV.

Prevalence of facet joint arthritis and its association with spinal pain in mountain population - A cross-sectional study

Introduction:

People living in the mountains are subject to tough terrain and climbing biomechanics which lead to degeneration of the spine and Facet joint arthritis (FJA).

Aims:

The goal of present study was (1) to know the prevalence of facet joint arthritis on CT scans in mountain population in regard to (a) different levels in spine (b) age (c) sex (2) to know if there is any significant association between FJA and spinal pain at that corresponding level.

Materials and Methods:

Bilateral Facet joints of 210 participants (age range, 18 to 97 years) who underwent MDCT imaging for reasons other than spinal pain, were graded and statistically analysed with SPSS software in this study. FJA was defined as at least one joint affected by facet joint disease (grade 2).

Results:

In our study, Seventy two men (68.5%) and eighty four women (80%) had Facet Joint arthritis. The difference between men and women in the prevalence of FJA was not statistically significant (P = 0.058). The increasing age demonstrated a higher prevalence of facet joint arthritis with statistical significance (P = 0.000). In dorsal and lumbar spine region, there was a statistically significant difference in prevalence of FJA according to spinal level. The prevalence of FJA grade 2 in cervical and dorsal spine region was associated with spinal pain in both men (P = 0.000) and women (P = 0.000). However, no statistically significant association was found between FJA grade 2 and spinal pain in lumbar spine region in both males (P = 0.680) and females (P = 0.680) as well as in total population (P = 0.513).

Conclusions:

People residing and actually ambulating in the mountain regions and exposed to the terrain have higher prevalence of Facet joint arthritis as compared to general population and this may be an independent risk factor for development of facet joint arthritis. However, a statistically significant relation between FJA and spinal pain exists only in cervical and dorsal spine.

Use of Single-Photon Emission Computed Tomography Imaging for Hypermetabolic Facet Identification in Diagnosis of Cervical and Axial Back Pain

BACKGROUND

Few studies have used hybrid single-photon emission computed tomography (SPECT)/computed tomography (CT) scan to identify degenerative facet disease. We aimed to determine the incidence of hypermetabolic facets on SPECT/CT imaging in patients with axial neck or back pain to elucidate the value of SPECT/CT scan in identifying pain generators.

METHODS

A retrospective review of adult patients with axial neck or back pain was conducted. A total of 190 patients underwent high-resolution SPECT/CT imaging using a standardized protocol from January 2010 to April 2018. Facet joints with increased radionuclide uptake on SPECT imaging were characterized as hypermetabolic. Number, level, and laterality of hypermetabolic facets were recorded based on review of imaging and radiologist impressions.

RESULTS

The average age of the patients was 58 ± 13 years, and 51% of patients were men. A total of 85 patients (48%) demonstrated zygapophyseal joint hypermetabolism (ZJH) on SPECT imaging. A total of 202 hypermetabolic facets were identified, indicating the average number of facets with ZJH was 2.38 ± 1.91. Of patients with a positive scan, lumbar facets were most commonly affected (69% of ZJH) followed by cervical (24%) and thoracic regions (6%). C1-2 and C2-3 (22% each of cervical ZJH) and L4-5 (32% of lumbar ZJH) were most commonly affected in the cervical and lumbar regions, respectively.

CONCLUSIONS

Nearly half of all patients with axial neck or back pain demonstrated ZJH on SPECT/CT imaging, supporting ZJH sites as potential pain generators and targets for treatment. Our results support the role for SPECT/CT imaging in the workup of patients with axial neck or back pain, which may reduce invasive diagnostic procedures and aid in treatment planning.

Association between lumbar disc herniation and facet joint osteoarthritis

Background

This study was performed to investigate the association between lumbar disc herniation (LDH) and facet joint osteoarthritis (FJOA) using magnetic resonance imaging (MRI).

Methods

Between March 2012 and September 2018, a total of 441 segments from 394 patients with LDH were included in the study. LDH was classified according to the Michigan State University (MSU) classification, in which the degree of LDH is divided into 3 levels (expressed as 1, 2, and 3) and the location of LDH is divided into 4 zones (described as A, AB, B, and C). Bilateral FJOA was graded from 0 to 3 using the criteria introduced by Weishaupt et al., and bilateral facet orientations were measured on axial MRI slices. A mixed-effects ordinal logistic regression model was utilized to determine the potential factors that may be associated with FJOA, including sex, age, body mass index (BMI), segment, facet orientation and tropism, and the degree and location of LDH.

Results

In general, the prevalence of FJOA (grade ≥ 2) was 66.2% in LDH segments. For both the left and right sides, the degree of LDH was associated with the severity of FJOA (p < 0.01). Age and BMI were also associated with the severity of left and right FJOA (p = 0.002 and p < 0.001 for age, p < 0.001 and p = 0.003 for BMI, respectively), while segment, facet orientation, and facet tropism were not (p > 0.05 for all). Notably, MSU-B LDH was associated with greater odds of having more severe FJOA on the herniation side (left: p < 0.001, odds ratio (OR) = 2.714, 95% confidence interval (CI) = 1.583~4.650; right: p = 0.003, OR = 2.615, 95% CI = 1.405~4.870). However, other locations of LDH were not associated with the severity of FJOA (p > 0.05 for all).

Conclusions

Both the degree of LDH and MSU-B LDH are associated with the severity of FJOA. The association between LDH and FJOA highlights the complexity of the etiology of FJOA.

A Longitudinal Study of Trunk Muscle Properties and Severity of Thoracic Kyphosis in Women and Men: The Framingham Study

BACKGROUND

Cross-sectional studies suggest that trunk muscle morphology in the lumbar spine is an important determinant of kyphosis severity in older adults. The contribution of age-related changes in muscle morphology in the thoracic and lumbar spine to progression of kyphosis is not known. Our objective was to determine cross-sectional and longitudinal associations of thoracic and lumbar muscle size and density with kyphosis.

METHODS

Participants were 1,087 women and men (mean age: 61 years) of the Framingham Heart Study who underwent baseline and follow-up quantitative computed tomography (QCT) scanning 6 years apart. We used QCT scans to measure trunk muscle cross-sectional area (CSA, cm2) and density (HU) at the thoracic and lumbar spine and Cobb angle (degrees) from T4 to T12. Linear regression models estimated the association between muscle morphology and kyphosis.

RESULTS

At baseline, smaller muscle CSA and lower density of thoracic (but not lumbar) spine muscles were associated with a larger (worse) Cobb angle in women and men. For example, each standard deviation decrease in baseline thoracic paraspinal muscle CSA was associated with a larger baseline Cobb angle in women (3.7 degrees, 95% CI: 2.9, 4.5) and men (2.5 degrees, 95% CI: 1.6, 3.3). Longitudinal analyses showed that loss of muscle CSA and density at the thoracic and lumbar spine was not associated with progression of kyphosis.

CONCLUSIONS

Our findings suggest that kyphosis severity is related to smaller and lower density trunk muscles at the thoracic spine. Future studies are needed to determine how strengthening mid-back musculature alters muscle properties and contributes to preventing kyphosis progression.

Outcome of intra-articular lumbar facet joint corticosteroid injection according to the severity of facet joint arthritis

Lumbar facet joint osteoarthritis (FJOA) caused by degenerative change(s) is considered to be the main cause of facet joint-origin low back pain (LBP). Intra-articular lumbar facet joint (IA LFJ) corticosteroid injection is widely used for controlling pain induced by FJOA. In the current study, the outcomes of IA LFJ corticosteroid injection were evaluated according to the severity of FJOA. A total of 50 patients who received IA LFJ corticosteroid injections for the treatment of LFJ pain were recruited. Patients were classified into three groups according to the severity of FJOA, which was indicated during a lumbar axial MRI. A total of 10 patients were assigned to group A (patients with mild FJOA), 27 to group B (patients with moderate FJOA) and 13 to group C (patients with severe FJOA). Pain intensity was evaluated using a numerical rating scale (NRS) prior to treatment and at 1, 2 and 3 months after treatment. A total of 26 (52%) patients experienced successful treatment outcomes (defined as >50% reduction in NRS score at 3 months). Patients in all groups demonstrated a significant decrease in NRS scores at 1, 2 and 3 months after IA LFJ corticosteroid injection compared with the pre-treatment score (P<0.001). However, the effect of IA LFJ corticosteroid injection was not significantly different among the three groups (P=0.889). The results demonstrated that facet joint-origin LBP was significantly reduced after IA LFJ corticosteroid injection, regardless of the severity of FJOA. The results of the current study indicated that IA LFJ corticosteroid injection is a beneficial clinical option for managing LBP caused by FJOA.

Concentration-Dependent Effects of Fibroblast-Like Synoviocytes on Collagen Gel Multiscale Biomechanics and Neuronal Signaling: Implications for Modeling Human Ligamentous Tissues

Abnormal loading of a joint's ligamentous capsule causes pain by activating the capsule's nociceptive afferent fibers, which reside in the capsule's collagenous matrix alongside fibroblast-like synoviocytes (FLS) and transmit pain to the dorsal root ganglia (DRG). This study integrated FLS into a DRG-collagen gel model to better mimic the anatomy and physiology of human joint capsules; using this new model, the effect of FLS on multiscale biomechanics and cell physiology under load was investigated. Primary FLS cells were co-cultured with DRGs at low or high concentrations, to simulate variable anatomical FLS densities, and failed in tension. Given their roles in collagen degradation and nociception, matrix-metalloproteinase (MMP-1) and neuronal expression of the neurotransmitter substance P were probed after gel failure. The amount of FLS did not alter (p > 0.3) the gel failure force, displacement, or stiffness. FLS doubled regional strains at both low (p < 0.01) and high (p = 0.01) concentrations. For high FLS, the collagen network showed more reorganization at failure (p < 0.01). Although total MMP-1 and neuronal substance P were the same regardless of FLS concentration before loading, protein expression of both increased after failure, but only in low FLS gels (p ≤ 0.02). The concentration-dependent effect of FLS on microstructure and cellular responses implies that capsule regions with different FLS densities experience variable microenvironments. This study presents a novel DRG-FLS co-culture collagen gel system that provides a platform for investigating the complex biomechanics and physiology of human joint capsules, and is the first relating DRG and FLS interactions between each other and their surrounding collagen network.

INTER-OBSERVER REPRODUCIBILITY OF THE “LUMBAR FACET HYPERSIGNAL CLASSIFICATION” AND THE CLASSIFICATION OF PFIRRMANN

ABSTRACT Objective: To evaluate the inter-observer relationship of the “lumbar facet hypersignal classification” and the correlation with disc degeneration. Methods: Retrospective study of magnetic resonance images obtained from 24 (N=24) patients (9 males and 15 females), aged 35 to 79 years, mean age 48 years and 1 month. The images were reviewed by two spine surgeons, by five orthopedists in training in the specialty of spine surgery and one radiologist to evaluate and quantify the presence of hypersignal lumbar facet and the Pfirrmann Classification for disc degeneration. Results: One hundred and twenty lumbar discs and their joint facets were evaluated by the eight examiners, with data analyzed by the Cronbach test and the Spearman Correlation Analysis with statistically high results, confirming good inter-observer relation for the “Lumbar Facet Hypersignal Classification” and for the classification of Pfirrmann. There was no statistically significant relationship between facet arthrosis and disc degeneration. Conclusions: The results confirm that there is good inter-observer relationship for the classification of Facet Hypersignal and for the Classification of Pfirrmann. However, in spite of a positive relationship, a correlation between facet arthrosis and disc degeneration was not statistically significant. Level of Evidence III; Retrospective Comparative Study.

Trends in lumbar radiofrequency ablation utilization from 2007 to 2016

BACKGROUND CONTEXT

Lumbar radiofrequency ablation (RFA) is an intervention used to treat facet-mediated chronic low back pain. In some studies with methods consistent with clinical practice guidelines, RFA results in improvements in pain and functional limitations. However, in other studies, RFA demonstrates limited benefit. Despite unanswered questions regarding efficacy of RFA, its use is widespread.

PURPOSE

To describe trends in the utilization and cost of lumbar RFA and lumbar facet injections.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

The sample was derived from the IBM/Watson MarketScan Commercial Claims and Encounters Databases from 2007 to 2016.

OUTCOME MEASURES

Longitudinal trends in the distribution and quantity of lumbar facet injections before lumbar RFA, corticosteroid administration during lumbar facet injections, progression to lumbar RFA after lumbar facet injections, lumbar RFA utilization, and costs of these interventions.

METHODS

Two primary cohorts were identified from patients who received lumbar RFA or lumbar facet injection procedures. Utilization rates per 100,000 enrollees were determined for both cohorts. The mean, median, and interquartile ranges of the number of facets targeted and costs per procedure were calculated by year and laterality, as well as overall. Costs in 2018 dollars were estimated by summing gross payment totals from patients and insurance plans. This study was supported by funds from the NIH, and has no conflict of interest associated biases.

RESULTS

From 2007 to 2016, lumbar RFA sessions performed per 100,000 enrollees per year increased from 49 to 113, a 130.6% overall increase (9.7% annually). Lumbar facet injection use increased from 201 to 251 sessions per 100,000 enrollees, a 24.9% overall increase (2.5% annually). In the year after a lumbar facet injection, 26.7% of patients received lumbar RFA; 28.6% received another injection but not RFA; and 44.7% received neither. The number of patients receiving two lumbar facet injection procedures prior to lumbar RFA grew from 51.1% in 2010 to 58.8% in 2016. For lumbar RFA, the cost per 100,000 enrollees went from $94,570 in 2007 to $266,680 in 2016, a 12.2% annual increase. For lumbar facet injections, the cost per 100,000 enrollees went from $257,280 in 2007 to $396,580 in 2016, a 4.9% annual increase.

CONCLUSIONS

This analysis showed consistent growth in both the frequency and procedure cost of lumbar RFA and facet injections among a large, national, commercially insured population from 2007 to 2016.

Agreement of clinical examination for low back pain with facet joint origin

Background:

Low back pain (LBP) with facet joint origin is a common diagnosis of patients referred to physical therapy clinic. An expert consensus of diagnostic criteria has been proposed. However, the reliability of the assessment has not been proved.

Objective:

To test the degrees of agreement between two physical therapists for nine physical examination items and the diagnosis of facet joint origin.

Methods:

The examination according to diagnostic criteria was performed independently by two physical therapists in 45 patients with chronic LBP. The percent agreements and Kappa coefficients of each examination item and diagnostic conclusion were calculated.

Results:

The percent agreements of nine examined items ranged from 73.3–91.1%. The Kappa coefficients, widely ranged from 0.250–0.690 (p=0.48 to <0.001), showed statistically significant agreements for all examination items. The low level of agreements was partly due to improper distributions of test results. The agreement of conclusion was 86.7% and Kappa coefficient was 0.492 (p=0.001) which reflected good agreement of facet diagnosis.

Conclusion:

There were adequate agreements for clinical examination of LBP with facet joint origin. The low level of agreement suggested the clinicians to have operational definition and rigorous training sessions although the examinations seemed to be routinely performed.

Do lumbar magnetic resonance imaging changes predict neuropathic pain in patients with chronic non-specific low back pain?

The aim of this observational, cross-sectional study was to analyse lumbar magnetic resonance imaging (MRI) findings in patients with non-specific chronic low back pain (CLBP), and to evaluate any correlation with pain intensity and their capacity to predict neuropathic pain (NP) in these patients.Fifty-two patients with non-specific CLBP, between 21 and 62 years of age, 50% men, were investigated. Lumbar MRI was employed to assess disc degeneration, endplate changes, Modic changes, disc displacement, facet degeneration, foraminal stenosis and central lumbar spinal stenosis. The characteristics of pain were evaluated and patients were divided into 2 subgroups: with NP (24 patients) and without NP (28 patients), based on the results of a DN4-interview. Correlations between particular MRI changes and their relations to the intensity of pain were evaluated. Logistic regression was used to disclose predictors of NP.Lumbar spine degenerative features were frequent in patients with non-specific CLBP, with L4/5 the most affected level. A significant correlation emerged between the severity of degenerative changes in particular lumbar spine structures (correlation coefficient ranging between 0.325 and 0.573), while no correlation was found between severity of degenerative changes and pain. Multivariate logistic regression revealed only 2 independent predictors of NP - female sex (odds ratio [OR] = 11.9) and a mean pain intensity of ≥4.5 in the previous 4 weeks (OR = 13.1).Degenerative changes in the lumbar spine are frequent MRI findings, but do not correlate with the intensity of pain and do not predict NP. However, female sex and pain intensity do predict NP.

A longitudinal study of disc height narrowing and facet joint osteoarthritis at the thoracic and lumbar spine, evaluated by computed tomography: the Framingham Study

BACKGROUND CONTEXT

Prevalence and progression of disc height narrowing (DHN) and facet joint osteoarthritis (FJOA) in the thoracic and lumbar regions in non-clinical populations are not well established.

PURPOSE

The present study aimed to use computed tomography (CT) images to determine the prevalence and progression of DHN and FJOA according to age, sex, and spinal region.

STUDY DESIGN

This is a 6-year longitudinal study.

SAMPLE

A total of 1,195 members of the Framingham Study (mean baseline age 61±9 years) were included in the study.

OUTCOME MEASURES

We compared the prevalence and progression (new or worsening) of moderate-to-severe DHN and FJOA by age, sex, and spinal region.

METHODS

A musculoskeletal radiologist evaluated DHN and FJOA from T4/T5 to L4/L5 on baseline and follow-up CT images using a semi-quantitative scale: 0=normal, 1=mild, 2=moderate, and 3=severe.

RESULTS

One-third or more of women and men ages 40-59 years at baseline had imaged-based evidence of prevalent DHN, more than half had prevalent FJOA, and DHN and FJOA prevalence increased approximately two- to fourfold in those age 60-69 and 70-89 years at baseline, respectively (p<.01). Progression of DHN and FJOA occurred more frequently at the lumbar than at the thoracic spine and more in women than in men (DHN: odds ratio [OR]=1.42, 95% confidence interval [CI]=1.07, 1.88; FJOA: OR=1.70, CI=1.33, 2.17).

CONCLUSIONS

Prevalence and progression of moderate-to-severe DHN and FJOA are common in non-clinical populations of older adults. The high frequency of spinal degeneration observed on CTs in this community-based study may contribute to challenges in interpreting the clinical significance of imaging evidence of DHN and FJOA. Future studies investigating the association of CT-based spinal degenerative features with pain and functional impairments in population-based samples are needed to help determine the clinical significance of imaged-based findings of DHN and FJOA.

Genome-wide meta-analysis of 158,000 individuals of European ancestry identifies three loci associated with chronic back pain

Back pain is the #1 cause of years lived with disability worldwide, yet surprisingly little is known regarding the biology underlying this symptom. We conducted a genome-wide association study (GWAS) meta-analysis of chronic back pain (CBP). Adults of European ancestry were included from 15 cohorts in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and from the UK Biobank interim data release. CBP cases were defined as those reporting back pain present for ≥3-6 months; non-cases were included as comparisons ("controls"). Each cohort conducted genotyping using commercially available arrays followed by imputation. GWAS used logistic regression models with additive genetic effects, adjusting for age, sex, study-specific covariates, and population substructure. The threshold for genome-wide significance in the fixed-effect inverse-variance weighted meta-analysis was p<5×10(-8). Suggestive (p<5×10(-7)) and genome-wide significant (p<5×10(-8)) variants were carried forward for replication or further investigation in the remaining UK Biobank participants not included in the discovery sample. The discovery sample comprised 158,025 individuals, including 29,531 CBP cases. A genome-wide significant association was found for the intronic variant rs12310519 in SOX5 (OR 1.08, p = 7.2×10(-10)). This was subsequently replicated in 283,752 UK Biobank participants not included in the discovery sample, including 50,915 cases (OR 1.06, p = 5.3×10(-11)), and exceeded genome-wide significance in joint meta-analysis (OR 1.07, p = 4.5×10(-19)). We found suggestive associations at three other loci in the discovery sample, two of which exceeded genome-wide significance in joint meta-analysis: an intergenic variant, rs7833174, located between CCDC26 and GSDMC (OR 1.05, p = 4.4×10(-13)), and an intronic variant, rs4384683, in DCC (OR 0.97, p = 2.4×10(-10)). In this first reported meta-analysis of GWAS for CBP, we identified and replicated a genetic locus associated with CBP (SOX5). We also identified 2 other loci that reached genome-wide significance in a 2-stage joint meta-analysis (CCDC26/GSDMC and DCC).

Real-time fusion-imaging in low back pain: a new navigation system for facet joint injections

AIMS AND OBJECTIVES

The aim of the current study is to present our experience in lumbar spine interventional procedures performed with a newly developed multimodal echo-navigator (EcoNav) and to evaluate short-term clinical outcomes of a series of patients affected by facet joint disease (FJD) treated with steroid and anaesthetic injection under fusion-imaging guidance, compared to a cohort of patients that received the same treatment under computed tomography (CT) guidance.

METHODS

Sixty-five consecutive patients (34 females; mean age 68.3 ± 12.8 years) with a clinical diagnosis of non-radicular low back pain lasting for more than 6-weeks and magnetic resonance (MR) or CT confirmed FJD were enrolled for image-guided FJI. Twenty-eight patients underwent FJI with fusion-guided technique, while CT-guided procedures were performed in the other cases. Clinical and procedural data were recorded and compared at a mean follow-up of 6.1 ± 2.0 months.

RESULTS

A significant improvement in clinical parameters was observed for both fusion-guided and CT-guided group. Comparing both groups, no statistically significant difference could be detected neither at baseline conditions nor during the follow-up period. No significant periprocedural complication occurred in both groups. A satisfaction rate of 92.3 and 81.1% was reported for fusion-guided and CT-guided group, respectively.

CONCLUSION

EcoNav fusion-imaging system represents a safe, feasible, effective and reproducible guidance option in FJD infiltration procedures, also avoiding use of ionising radiations.

Facet Joints of the Spine: Structure–Function Relationships, Problems and Treatments, and the Potential for Regeneration

The zygapophysial joint, a diarthrodial joint commonly referred to as the facet joint, plays a pivotal role in back pain, a condition that has been a leading cause of global disability since 1990. Along with the intervertebral disc, the facet joint supports spinal motion and aids in spinal stability. Highly susceptible to early development of osteoarthritis, the facet is responsible for a significant amount of pain in the low-back, mid-back, and neck regions. Current noninvasive treatments cannot offer long-term pain relief, while invasive treatments can relieve pain but fail to preserve joint functionality. This review presents an overview of the facet in terms of its anatomy, functional properties, problems, and current management strategies. Furthermore, this review introduces the potential for regeneration of the facet and particular engineering strategies that could be employed as a long-term treatment.

Novel Ex Vivo Human Osteochondral Explant Model of Knee and Spine Osteoarthritis Enables Assessment of Inflammatory and Drug Treatment Responses

Osteoarthritis of the knee and spine is highly prevalent in modern society, yet a disease-modifying pharmacological treatment remains an unmet clinical need. A major challenge for drug development includes selection of appropriate preclinical models that accurately reflect clinical phenotypes of human disease. The aim of this study was to establish an ex vivo explant model of human knee and spine osteoarthritis that enables assessment of osteochondral tissue responses to inflammation and drug treatment. Equal-sized osteochondral fragments from knee and facet joints (both n = 6) were subjected to explant culture for 7 days in the presence of a toll-like receptor 4 (TLR4) agonist and an inhibitor of transforming growth factor-beta (TGF-β) receptor type I signaling. Markers of inflammation, interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1), but not bone metabolism (pro-collagen-I) were significantly increased by treatment with TLR4 agonist. Targeting of TGF-β signaling resulted in a strong reduction of pro-collagen-I and significantly decreased IL-6 levels. MCP-1 secretion was increased, revealing a regulatory feedback mechanism between TGF-β and MCP-1 in joint tissues. These findings demonstrate proof-of-concept and feasibility of explant culture of human osteochondral specimens as a preclinical disease model, which might aid in definition and validation of disease-modifying drug targets.

Comparative Analysis of Bone Structural Parameters Reveals Subchondral Cortical Plate Resorption and Increased Trabecular Bone Remodeling in Human Facet Joint Osteoarthritis

Facet joint osteoarthritis is a prominent feature of degenerative spine disorders, highly prevalent in ageing populations, and considered a major cause for chronic lower back pain. Since there is no targeted pharmacological therapy, clinical management of disease includes analgesic or surgical treatment. The specific cellular, molecular, and structural changes underpinning facet joint osteoarthritis remain largely elusive. The aim of this study was to determine osteoarthritis-related structural alterations in cortical and trabecular subchondral bone compartments. To this end, we conducted comparative micro computed tomography analysis in healthy (n = 15) and osteoarthritic (n = 22) lumbar facet joints. In osteoarthritic joints, subchondral cortical plate thickness and porosity were significantly reduced. The trabecular compartment displayed a 42 percent increase in bone volume fraction due to an increase in trabecular number, but not trabecular thickness. Bone structural alterations were associated with radiological osteoarthritis severity, mildly age-dependent but not gender-dependent. There was a lack of association between structural parameters of cortical and trabecular compartments in healthy and osteoarthritic specimens. The specific structural alterations suggest elevated subchondral bone resorption and turnover as a potential treatment target in facet joint osteoarthritis.

Characterisation of the correlation between standing lordosis and degenerative joint disease in the lower lumbar spine in women and men: a radiographic study

BACKGROUND

Degenerative joint disease (DJD) in the lumbar spine is a common condition that is associated with chronic low back pain. Excessive loading of lumbar joints is a risk factor for DJD. Changes in lumbar lordosis significantly redistribute the forces of weight-bearing on the facet joints and the intervertebral discs. However, the relationship between lumbar lordosis and DJD has not been characterized in men and women.

METHODS

We characterised the correlation between standing lumbar lordosis and DJD in standing radiographic images from 301 adult female and male chiropractic patients. DJD was rated using the Kellgren-Lawrence scale, and lordosis was measured using the Cobb angle. Linear and curvilinear correlations were investigated while controlling for age and sex.

RESULTS

We found a highly significant curvilinear correlation between lordosis and DJD of the lower lumbar spine in both sexes, but especially in women, irrespective of the effects of age. We found the effect size of lordosis on lower lumbar DJD to be between 17.4 and 18.1% in women and 12.9% in older men. In addition, lordosis of 65 (95% CI 55.3-77.7) and 68 (98% CI 58.7-73.3) degrees were associated with minimal DJD in the lower lumbar spine of women and men respectively, and were therefore considered 'optimal'. This optimal lordotic angle was 73 (95% CI 58.8-87.2) degrees in older men.

CONCLUSIONS

Both hypo- and hyper-lordosis correlate with DJD in the lumbar spine, particularly in women and in older men. These findings may well be of relevance to spinal pain management and spinal rehabilitation.

The Kinematics and Spondylosis of the Lumbar Spine Vary Depending on the Levels of Motion Segments in Individuals With Low Back Pain

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

The aim of this study was to identify associations of spondylotic and kinematic changes with low back pain (LBP).

SUMMARY OF BACKGROUND DATA

The ability to characterize and differentiate the biomechanics of both the symptomatic and asymptomatic lumbar spine is crucial to alleviate the sparse literature on the association of lumbar spine biomechanics and LBP.

METHODS

Lumbar dynamic plain radiographs (flexion-extension), dynamic computed tomography (CT) scanning (axial rotation, disc height), and magnetic resonance imaging (MRI, disc and facet degeneration grades) were obtained for each subject. These parameters were compared between symptomatic and control groups using Student t test and multivariate logistic regression, which controlled for patient age and sex and identified spinal parameters that were independently associated with symptomatic LBP. Disc grade and mean segmental motion by level were tested by one-way analysis of variance (ANOVA).

RESULTS

Ninety-nine volunteers (64 asymptomatic/35 LBP) were prospectively recruited. Mean age was 37.3 ± 10.1 years and 55% were male. LBP showed association with increased L5/S1 translation [odds ratio (OR) 1.63 per mm, P = 0.005], decreased flexion-extension motion at L1/L2 (OR 0.87 per degree, P = 0.036), L2/L3 (OR 0.88 per degree, P = 0.036), and L4/L5 (OR 0.87 per degree, P = 0.020), increased axial rotation at L4/L5 (OR 2.11 per degree, P = 0.032), decreased disc height at L3/L4 (OR 0.52 per mm, P = 0.008) and L4/L5 (OR 0.37 per mm, p < 0.001), increased disc grade at all levels (ORs 2.01-12.33 per grade, P = 0.001-0.026), and increased facet grade at L4/L5 (OR 4.99 per grade, P = 0.001) and L5/S1 (OR 3.52 per grade, P = 0.004). Significant associations were found between disc grade and kinematic parameters (flexion-extension motion, axial rotation, and translation) at L4/L5 (P = 0.001) and L5/S1 (P < 0.001), but not at other levels (P > 0.05).

CONCLUSION

In symptomatic individuals, L4/L5 and L5/S1 levels were affected by spondylosis and kinematic changes. This study clarifies the relationships between kinematic alterations and LBP, mostly observed at the above-mentioned segments.

LEVEL OF EVIDENCE

N/A.

Characterization of facet joint cartilage properties in the human and interspecies comparisons

The facet joint, a synovial joint located on the posterior-lateral spine, is highly susceptible to degenerative changes and plays a significant role in back-related morbidities. Despite its significance, the facet is rarely studied and thus current treatment strategies are lacking. This study aimed to characterize, for the first time, the properties of human, pig, monkey, and rabbit lumbar facet cartilage providing much-needed design criteria for tissue engineering approaches. In this study, where possible, the facet's morphological, histological, mechanical, and biochemical properties were evaluated. Comparisons between the properties of the inferior and superior facet surfaces, as well as among spinal levels were performed within each species. In addition, interspecies comparisons of the properties were determined. The human facet joint was found to be degenerated; 100% of joint surfaces showed signs of pathology and approximately 71% of these were considered to be grade 4. Joint morphology varied among species, demonstrating that despite the mini-pig facet being closest to the human in terms of width and length, it was far more curved than the human or any of the other species. No notable differences were found in the mini-pig, monkey, and rabbit mechanical and biochemical properties, suggesting that these species, despite morphological differences, may serve as suitable animal models for studying structure-function relationships of the human facet joint. The characterization data reported in this study may increase our understanding of this ill-described joint as well as provide the foundation for the development of new treatments such as tissue engineering.

STATEMENT OF SIGNIFICANCE

This work provides the first comprehensive description of the properties of lumbar facet joint cartilage. Importantly, this work establishes that histological, biochemical, and mechanical properties are comparable between bipedal and quadrupedal animals, helping to guide future selection of appropriate animal models. This work also suggests that the human facet joint is highly susceptible to pathology. The mechanical properties of facet cartilage, found to be inferior to those of other synovial joints, provide a greater understanding of the joint's structure-function relationships as well as the potential etiology of facet joint pathology. Lastly, this work will serve as the foundation for the development of much-needed facet joint treatments, especially those based on tissue engineering approaches.

GEORG-SCHMORL-PRIZE OF THE GERMAN SPINE SOCIETY (DWG) 2016: Comparison of in vitro osteogenic potential of iliac crest and degenerative facet joint bone autografts for intervertebral fusion in lumbar spinal stenosis

PURPOSE

The promotion of spinal fusion using bone autografts is largely mediated by the osteoinductive potential of progenitors/mesenchymal stem cells (MSC) that reside in the marrow spaces of cancellous bone. Iliac crest is the common autograft donor site, but its use presents an increased risk for donor site pain, morbidity and infection. Degenerative bone samples harvested during facetectomy might provide an alternative viable source of osteoinductive autografts. In this study, we conducted an intra-individual comparison of the osteogenic potential of isolated low passage MSC from both sources.

METHODS

Iliac crest and degenerative facet joints were harvested from eight consecutive patients undergoing transforaminal lumbar interspinal fusion due to lumbar spinal stenosis. MSC were isolated by collagenase digestion, selected by plastic adherence and minimally expanded for downstream assays. Clonogenic and osteogenic potential was evaluated by colony formation assays in control and osteogenic culture medium. Osteogenic properties, including alkaline phosphatase (ALP) induction, matrix mineralization and type I collagen mRNA and protein expression were characterized using quantitative histochemical staining and reverse transcription PCR. Spontaneous adipogenesis was analysed by adipocyte enumeration and gene expression analysis of adipogenic markers.

RESULTS

Average colony-forming efficiency in osteogenic medium was equal between iliac crest (38 ± 12%) and facet joint (36 ± 11%). Osteogenic potential at the clonal level was 55 ± 26 and 68 ± 17% for iliac crest and facet joint MSC, respectively. Clonogenic and osteogenic potential were significantly negatively associated with donor age. Osteogenic differentiation led to significant induction of ALP activity in iliac crest (sixfold) and facet joint (eightfold) MSC. Matrix mineralization quantified by Alizarin red staining was increased by osteogenic differentiation, yet similar between both MSC sources. Protein expression of type I collagen was enhanced during osteogenesis and significantly greater in iliac crest MSC. Correspondingly, COL1A2 mRNA expression was higher in osteogenically differentiated MSC from iliac crest. Adipocyte numbers showed significant differences between iliac crest (63 ± 60) and facet joint (18 ± 15) MSC under osteogenic conditions. Negative (GREM1) and positive (FABP4) adipogenic markers were not differentially expressed between sources.

CONCLUSION

MSC from iliac crest and degenerative facet joints largely display similar clonogenic and osteogenic properties in vitro. Differences at the molecular level are not likely to impair the osteoinductive capacity of facet joint MSC. Bone autografts from facetectomy would be viable alternatives as bone autografts for intervertebral spinal fusion in lumbar spinal stenosis.

A Feasibility Study to Assess Vibration and Sound From Zygapophyseal Joints During Motion Before and After Spinal Manipulation

OBJECTIVE

This feasibility study used novel accelerometry (vibration) and microphone (sound) methods to assess crepitus originating from the lumbar spine before and after side-posture spinal manipulative therapy (SMT).

METHODS

This study included 5 healthy and 5 low back pain (LBP) participants. Nine accelerometers and 1 specialized directional microphone were applied to the lumbar region, allowing assessment of crepitus. Each participant underwent full lumbar ranges of motion (ROM), bilateral lumbar SMT, and repeated full ROM. After full ROMs the participants received side-posture lumbar SMT on both sides by a licensed doctor of chiropractic. Accelerometer and microphone recordings were made during all pre- and post-SMT ROMs. Primary outcome was a descriptive report of crepitus prevalence (average number of crepitus events/participant). Participants were also divided into 3 age groups for comparisons (18-25, 26-45, and 46-65 years).

RESULTS

Overall, crepitus prevalence decreased pre-post SMT (average pre = 1.4 crepitus/participant vs post = 0.9). Prevalence progressively increased from the youngest to oldest age groups (pre-SMT = 0.0, 1.67, and 2.0, respectively; and post-SMT = 0.5, 0.83, and 1.5). Prevalence was higher in LBP participants compared with healthy (pre-SMT-LBP = 2.0, vs pre-SMT-healthy = 0.8; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.8), even though healthy participants were older than LBP participants (40.8 years vs 27.8 years); accounting for age: pre-SMT-LBP = 2.0 vs pre-SMT-healthy = 0.0; post-SMT-LBP = 1.0 vs post-SMT-healthy = 0.3.

CONCLUSIONS

Our findings indicated that a larger study is feasible. Other findings included that crepitus prevalence increased with age, was higher in participants with LBP than in healthy participants, and overall decreased after SMT. This study indicated that crepitus assessment using accelerometers has the potential of being an outcome measure or biomarker for assessing spinal joint (facet/zygapophyseal joint) function during movement and the effects of LBP treatments (eg, SMT) on zygapophyseal joint function.

Feasibility study for evaluating early lumbar facet joint degeneration using axial T1 ρ, T2 , and T2* mapping in cartilage

PURPOSE

To assess the feasibility of axial T₂ , T2*, and T₁ ρ mapping of lumbar facet joint (LFJ) cartilage for evaluation of early degeneration.

MATERIALS AND METHODS

We examined a total of 176 LFJs from 21 volunteers using axial T₂ , T2*, and T₁ ρ mapping with a 3.0T magnetic resonance imaging (MRI) scanner. All LFJs were measured and grouped according to the presence of low back pain (LBP), the Weishaupt grading system, and the Pfirrmann grade of the adjacent intervertebral disk (IVD). T₂ , T2*, and T₁ ρ values were analyzed and compared among the different groups.

RESULTS

Low interobserver agreement was found in the Weishaupt grading of LFJs (κ = 0.161). The T₁ ρ values of LFJs were significantly different between adjacent two Pfirrmann grade of disks (grade I 50.15 ± 3.63 msec / grade II 53.27 ± 3.80 msec, P = 0.002; grade II 53.27 ± 3.80 msec / grade III 58.40 ± 4.17 msec, P < 0.01), and in different Weishaupt grades of LFJs (P = 0.000). T2* values were only found significantly different between Pfirrmann grade I and III of disks (P = 0.048). There was no significant difference in T₂ values of LFJs whatever in Pfirrmann (P = 0.556) or Weishaupt grades (P = 0.694). No significant difference was found in T₂ , T2*, and T₁ ρ values between volunteers with LBP and without LBP (P_T2  = 0.783, PT2*=0.311, P_T1 ρ = 0.259).

CONCLUSION

Axial T₁ ρ could be an effective and sensitive method to assess for early degenerative changes in LFJ cartilage.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:468-475.

In vivo feasibility of real-time MR-US fusion imaging lumbar facet joint injections

OBJECTIVES

Traditionally, facet joint injections (FJI) are performed under fluoroscopic or computed tomography (CT) guidance, mainly due to the deep anatomical location and the presence of bony landmarks. Fusion imaging technology, which couples the ultrasound scan with the corresponding CT or magnetic resonance (MR) image obtained from the diagnostic examination and reformatted in real time according to the ultrasound scanning plane, allows to combine the panoramic view and the elevated anatomical detail of MR or CT with the ease of use of ultrasound without patient exposure to ionizing radiation.

METHODS

Thirty eight patients (24 females; mean age ± SD: 64 ± 9 years) received MR fusion-assisted ultrasound-guided FJI of 1 ml of a mixture of local anaesthetic and corticosteroid using a ultrasound machine (Logiq E9, GE Healthcare) equipped with a GPS-enhanced fusion imaging technology which couples real-time B-mode images with those of the previous recent diagnostic MR examination. Low-dose CT needle positioning confirmation was performed in the first 28 patients. Patients' pain was recorded using a visual analogue scale (VAS), at baseline and at 2, 4 and 8 weeks.

RESULTS

All fusion imaging-guided injections were performed successfully. Out of 112, 96 FJI had optimal intra-articular needle positioning (accuracy: 85.7%). Patients VAS significantly decreases after the procedure with no differences among who received CT needle positioning control and who did not receive it. No major complications were observed.

CONCLUSIONS

Ultrasound needle guidance with MR fusion assistance allows for safe and effective injection of degenerative facet joint disease.

Differences among primary care patients with different mechanical patterns of low back pain: a cross-sectional investigation

OBJECTIVES

To characterise and compare a persistent low back pain (LBP) population based on 4 clinical pain patterns.

DESIGN

Cross-sectional analysis of patient-reported data.

SETTING

Patients from 220 primary care practitioners in 3 cities in Ontario, Canada.

PARTICIPANTS

1020 individuals seeking LBP care.

INCLUSION CRITERIA

LBP symptoms lasting 1½-12 months, or unmanageable recurrent symptoms; ages 18+years.

EXCLUSION CRITERIA

pregnant/1-year postpartum; involved in active litigation or motor vehicle injury; emergent spinal presentations; pain disorder diagnosis; work injury claim; or constant symptoms persisting >12 months postonset.

MAIN OUTCOME MEASURE

Hall pain pattern subgroups: back dominant pain aggravated by flexion (P1) or extension (P2), or leg dominant constant (P3) or intermittent (P4) pain (multinomial logistic outcome; referent: P1).

RESULTS

Groups P1 and P2 had the highest proportion of women. P2 and P4 had higher mean ages and comorbidity counts. P3 and P4 had higher proportions of overweight/obese individuals and lower general health scores. Adjusted models: being male and overweight/obese was associated with increased odds of being in P3 (OR 1.64 (95% CI 1.10 to 2.46), and OR 1.74 (1.13 to 2.68), respectively) and P4 (OR 1.87 (1.11 to 3.15) and OR 1.91 (1.06 to 3.42), respectively), and increasing age with increased odds of being in P2 (OR 1.02 (1.01 to 1.03)) and P4 (OR 1.06 (1.04 to 1.08)). Increasing comorbidity count was associated with increased odds of being in P2 (OR 1.14 (1.0 to 1.3)), and better general health scores with decreased odds of being in P3 (OR 0.40 (0.18 to 0.93)).

CONCLUSIONS

This is the first study to examine the 'Hall system' in a non-rehab primary care population. Subgroups classified according to this system appear to have distinct profiles. Further research is needed to better characterise and determine the prognostic implication of these clinically derived subgroups.

Heritability of Thoracic Spine Curvature and Genetic Correlations With Other Spine Traits: The Framingham Study

Hyperkyphosis is a common spinal disorder in older adults, characterized by excessive forward curvature of the thoracic spine and adverse health outcomes. The etiology of hyperkyphosis has not been firmly established, but may be related to changes that occur with aging in the vertebrae, discs, joints, and muscles, which function as a unit to support the spine. Determining the contribution of genetics to thoracic spine curvature and the degree of genetic sharing among co-occurring measures of spine health may provide insight into the etiology of hyperkyphosis. The purpose of our study was to estimate heritability of thoracic spine curvature using T4 -T12 kyphosis (Cobb) angle and genetic correlations between thoracic spine curvature and vertebral fracture, intervertebral disc height narrowing, facet joint osteoarthritis (OA), lumbar spine volumetric bone mineral density (vBMD), and paraspinal muscle area and density, which were all assessed from computed tomography (CT) images. Participants included 2063 women and men in the second and third generation offspring of the original cohort of the Framingham Study. Heritability of kyphosis angle, adjusted for age, sex, and weight, was 54% (95% confidence interval [CI], 43% to 64%). We found moderate genetic correlations between kyphosis angle and paraspinal muscle area (ρˆG , -0.46; 95% CI, -0.67 to -0.26), vertebral fracture (ρˆG , 0.39; 95% CI, 0.18 to 0.61), vBMD (ρˆG , -0.23; 95% CI, -0.41 to -0.04), and paraspinal muscle density (ρˆG , -0.22; 95% CI, -0.48 to 0.03). Genetic correlations between kyphosis angle and disc height narrowing (ρˆG , 0.17; 95% CI, -0.05 to 0.38) and facet joint OA (ρˆG , 0.05; 95% CI, -0.15 to 0.24) were low. Thoracic spine curvature may be heritable and share genetic factors with other age-related spine traits including trunk muscle size, vertebral fracture, and bone mineral density. © 2016 American Society for Bone and Mineral Research.

Identification of microRNA-181a-5p and microRNA-4454 as mediators of facet cartilage degeneration

Osteoarthritis (OA) of spine (facet joints [FJs]) is one of the major causes of severe low back pain and disability worldwide. The degeneration of facet cartilage is a hallmark of FJ OA. However, endogenous mechanisms that initiate degeneration of facet cartilage are unknown, and there are no disease-modifying therapies to stop FJ OA. In this study, we have identified microRNAs (small noncoding RNAs) as mediators of FJ cartilage degeneration. We first established a cohort of patients with varying degrees of facet cartilage degeneration (control group: normal or mild facet cartilage degeneration; FJ OA group: moderate to severe facet cartilage degeneration) and then screened 2,100 miRNAs and identified 2 miRNAs (miR-181a-5p and miR-4454) that were significantly elevated in FJ OA cartilage compared with control facet cartilage. We further explored their role, function, and signaling mechanisms using computational, in vitro functional, and in vivo studies. We specifically indicate that miR-181a-5p and miR-4454 are involved in promoting inflammatory, catabolic, and cell death activity in FJ chondrocytes. This is the first report to our knowledge that identifies miR-181a-5p and miR-4454 as mediators of cartilage degeneration in FJs and potential therapeutic targets for stopping cartilage degeneration.

Characterization of subchondral bone histopathology of facet joint osteoarthritis in lumbar spinal stenosis

Facet joint osteoarthritis may be a cause of low back pain in degenerative spine diseases including lumbar spinal stenosis. Subchondral bone is regarded as a potential therapeutic target for osteoarthritis treatment. The goal of this study was to characterize subchondral bone histopathology in osteoarthritic facet joints from lumbar spinal stenosis patients. Fifteen patients with degenerative spinal stenosis scheduled for transforaminal lumbar interbody fusion surgery were recruited for this study. Osteoarthritis severity was graded on T1- and T2-weighted MRI images using Weishaupt scoring system. Dissected osteoarthritic facet joints were subjected to histological and immunohistochemistry analyses to study relative abundance of osteoblast, osteoclasts, and macrophages using van Gieson's, tartrate-resistant acid phosphatase and CD68-antibody staining, respectively. Presence of nerve fibers was evaluated by PGP9.5-antibody staining. Differential bone histopathology, independent from radiological osteoarthritis grade, was observed in facet joints. Extensive de novo bone formation was found in subchondral bone tissues of eight of fifteen specimens. Regions of bone formation showed high abundance of blood vessels and CD68-positive macrophages, but were devoid of multinucleated osteoclasts. Additional pathological changes in subchondral marrow spaces, including inflammatory infiltration and enhanced osteoclast activity, were characterized by macrophage-rich tissues. PGP9.5-positive nerve fibers were detected near arterioles, but not in regions displaying bone pathology. Individual histopathological parameters did not associate with clinical features or radiological osteoarthritis severity. Subchondral bone histopathology of facet joint osteoarthritis in lumbar spinal stenosis is characterized by marrow infiltration by macrophage-rich tissues and enhanced de novo bone formation. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1475-1480, 2016.

(18)F-Sodium Fluoride PET-CT Hybrid Imaging of the Lumbar Facet Joints: Tracer Uptake and Degree of Correlation to CT-graded Arthropathy

We aim to evaluate ¹⁸F-NaF uptake by facet joints with hybrid PET-CT technique. Specifically, we evaluate NaF uptake in the facet joints of the lower lumbar spine, and correlate with the morphologic grade of facet arthropathy on CT. 30 consecutive patients who underwent standard vertex to toes NaF PET-CT for re-staging of primary neoplastic disease without measurable or documented bony metastases were identified. Maximum (SUVmax) and average (SUVavg) standardized uptake values were calculated for each L3-4, L4-5, and L5-S1 facet joint (n = 180) and normalized to average uptake in the non-diseased femur. A Pathria grade (0-3) was assigned to each facet based upon the CT morphology. Spearman's rank correlation was performed for normalized SUVmax and SUVavg with Pathria grade. ANOVA was performed with Tukey-Kramer pairwise tests to evaluate differences in uptake between Pathria groups. Facet normalized SUVmax (r = 0.31, P < 0.001) and SUVavg (r = 0.28, P < 0.001) demonstrated a mild positive correlation with CT Pathria grade. There was a wide range of uptake values within each Pathria grade subgroup with statistically significant differences in uptake only between Pathria grade 3 as compared to grades 0, 1, and 2. In conclusion, NaF uptake and morphologic changes of the facet joint on CT are weakly correlated. Physiologic information provided by NaF uptake is often discrepant with structural findings on CT suggesting NaF PET may supplement conventional structural imaging for identification of pain generating facet joints. Prospective investigation into the relationship of facet joint NaF uptake with pain and response to pain interventions is warranted.

The correlation between radiographic and pathologic grading of lumbar facet joint degeneration

Background

Before performing spine non-fusion surgery that retains the facet joints, choosing an accurate radiographic method to evaluate the degree of facet joint degeneration is extremely important. Therefore, the objective of this study was to determine the accuracy and reliability of different radiographic classifications by analyzing the correlation between radiographic and pathologic grading of lumbar facet joint degeneration. Taking the pathologic examination as standard, the consistency of computed tomography (CT) and magnetic resonance imaging (MRI) assessment of lumbar facet joint degeneration was compared.

Methods

A total of 74 facet joints obtained from 42 patients who underwent posterior lumbar surgery were evaluated. All patients underwent CT and MRI before surgery. The pathologic grade was evaluated with a method based on hematoxylin-eosin and toluidine blue staining. The radiographic grade was evaluated using the methods proposed by different authors.

Results

There was a moderate consistency between pathologic and radiographic grading for facet joint degeneration. The weighted kappa coefficients comparing pathologic with radiographic grading were 0.506 for CT, 0.561 for MRI, and 0.592 for CT combined with MRI, respectively. Taking the pathologic examination as standard, the consistency of CT and MRI examination was also moderate, and the weighted kappa coefficient was 0.459.

Conclusion

The radiographic examination has moderate accuracy and reliability for evaluating degeneration of facet joints. Therefore, a more accurate method for evaluating the degeneration of facet joints is necessary before performing spine non-fusion surgery that retains the facet joints.

Electronic supplementary material

The online version of this article (doi:10.1186/s12880-016-0129-9) contains supplementary material, which is available to authorized users.

Multivariate Radiological-Based Models for the Prediction of Future Knee Pain: Data from the OAI

In this work, the potential of X-ray based multivariate prognostic models to predict the onset of chronic knee pain is presented. Using X-rays quantitative image assessments of joint-space-width (JSW) and paired semiquantitative central X-ray scores from the Osteoarthritis Initiative (OAI), a case-control study is presented. The pain assessments of the right knee at the baseline and the 60-month visits were used to screen for case/control subjects. Scores were analyzed at the time of pain incidence (T-0), the year prior incidence (T-1), and two years before pain incidence (T-2). Multivariate models were created by a cross validated elastic-net regularized generalized linear models feature selection tool. Univariate differences between cases and controls were reported by AUC, C-statistics, and ODDs ratios. Univariate analysis indicated that the medial osteophytes were significantly more prevalent in cases than controls: C-stat 0.62, 0.62, and 0.61, at T-0, T-1, and T-2, respectively. The multivariate JSW models significantly predicted pain: AUC = 0.695, 0.623, and 0.620, at T-0, T-1, and T-2, respectively. Semiquantitative multivariate models predicted paint with C-stat = 0.671, 0.648, and 0.645 at T-0, T-1, and T-2, respectively. Multivariate models derived from plain X-ray radiography assessments may be used to predict subjects that are at risk of developing knee pain.

Grading Osteoarthritic Changes of the Zygapophyseal Joints from Radiographs: A Reliability Study

OBJECTIVE

This study tested the reliability of a 5-point ordinal scale used to grade the severity of degenerative changes of zygapophyseal (Z) joints on standard radiographs.

METHODS

Modifications were made to a Kellgren grading system to improve agreement for grading the severity of osteoarthritic changes in lumbar Z joints. These included adding 1 grade of no degeneration, multiple radiographic views, and structured examiner training. Thirty packets of radiographic files were obtained, which included representation of all 5 grades including no degeneration (0) and Kellgren's 4-point (1-4) joint degeneration classification criteria. Radiographs were digitized to create a radiographic atlas that was given to examiners for individual study and blinded evaluation sessions. Intrarater and interrater agreement was determined by weighted κ (κw) from the examination of 79 Z joints (25 packets).

RESULTS

Using the modified scale and after training, examiners demonstrated a moderate-to-substantial level of interrater agreement (κw = 0.57, 0.60, and 0.68). Intrarater agreement was moderate (κw = 0.42 and 0.54).

CONCLUSIONS

The modified Kellgren 5-point grading system provides acceptable intrarater and interrater reliability when examiners are adequately trained. This grading system may be a useful method for future investigations assessing radiographic osteoarthritis of the Z joints.

Physical activity and associations with computed tomography-detected lumbar zygapophyseal joint osteoarthritis

BACKGROUND CONTEXT

There are no previous epidemiologic studies examining associations between physical activity and imaging-detected lumbar zygapophyseal joint osteoarthritis (ZJO) in a community-based sample.

PURPOSE

To determine whether physical activity is associated with prevalent lumbar ZJO on computed tomography (CT).

STUDY DESIGN/SETTING

A community-based cross-sectional study.

PATIENT SAMPLE

Four hundred twenty-four older adults from the Framingham Heart Study.

OUTCOME MEASURES

Participants received standardized CT assessments of lumbar ZJO at the L2-S1 levels. Severe lumbar ZJO was defined according to the presence and/or degree of joint space narrowing, osteophytosis, articular process hypertrophy, articular erosions, subchondral cysts, and intra-articular vacuum phenomenon. This definition of lumbar ZJO was based entirely on CT imaging findings and did not include any clinical criteria such as low back pain.

METHODS

Physical activity was measured using the Physical Activity Index, which estimate hours per day typically spent in these activity categories: sleeping, sitting, slight activity, moderate activity, and heavy activity. Participants reported on usual frequency of walking, running, swimming, and weightlifting. We used multivariable logistic regression to examine associations between self-reported activity and severe lumbar ZJO, while adjusting for key covariates including age, sex, height, and weight.

RESULTS

In multivariable analyses, ordinal categories of heavy physical activity duration per day were significantly associated with severe lumbar ZJO (p for trend=.04), with the greatest risk observed for the category 3 or more hours per day, odds ratio 2.13 (95% confidence interval [CI] 0.97-4.67). When heavy activity was modeled as a continuous independent variable, each hour was independently associated with 1.19 times the odds of severe lumbar ZJO (95% CI 1.03-1.38, p=.02). Less vigorous types of physical activity and the type of exercise were not associated with severe lumbar ZJO. Older age, lesser height, and greater weight were independently and significantly associated with severe lumbar ZJO. In multivariable models predicting lumbar ZJO, neither model discrimination nor reclassification improved with the addition of physical activity variables, compared with a multivariable model including age, sex, height, and weight.

CONCLUSIONS

Our findings demonstrate a statistically significant cross-sectional association between heavy physical activity and CT-detected severe lumbar ZJO. However, the additional discriminatory capability of heavy physical activity above and beyond that contributed by other factors was negligible.

Osteoarthritis year in review 2014: imaging

PURPOSE

This narrative review covers original publications related to imaging in osteoarthritis (OA) published in English between April 2013 and March 2014. In vitro data, animal studies and studies with less than 20 observations were not included.

METHODS

To extract relevant studies, an extensive PubMed database search was performed based on, but not limited to the query terms "Osteoarthritis" in combination with "MRI", "Imaging", "Radiography", "Ultrasound", "Computed Tomography" and "Nuclear Medicine". Publications were sorted according to relevance based on potential impact to the OA research community with the overarching goal of a balanced overview covering all aspects of imaging. Focus was on publications in high impact special interest journals. The literature will be presented in a methodological fashion covering radiography, ultrasound, compositional and morphologic Magnetic resonance imaging (MRI), and from an anatomic perspective including bone, muscle, meniscus and synovitis.

RESULTS AND CONCLUSIONS

Imaging research in OA in the last year was characterized by a strong focus on MRI-based studies dealing with epidemiological and methodological aspects of the disease. Ultrastructural tissue assessment specifically of cartilage and meniscus using compositional MRI is evolving further. Additional subsets of the large publicly available Osteoarthritis Initiative (OAI) MRI dataset are being analyzed at present and have been published with muscle analyses coming increasingly into the focus of the community. Bone parameters were evaluated using varying technology and a persistent interest in inflammatory disease manifestations has been noted. Other modalities than MRI have been less explored. To date most OA imaging research is still focused on the knee joint.

Longitudinal associations between incident lumbar spine MRI findings and chronic low back pain or radicular symptoms: retrospective analysis of data from the longitudinal assessment of imaging and disability of the back (LAIDBACK)

Background

There are few longitudinal cohort studies examining associations between incident MRI findings and incident spine-related symptom outcomes. Prior studies do not discriminate between the two distinct outcomes of low back pain (LBP) and radicular symptoms. To address this gap in the literature, we conducted a secondary analysis of existing data from the Longitudinal Assessment of Imaging and Disability of the Back (LAIDBACK). The purpose of this study was to examine the association of incident lumbar MRI findings with two specific spine-related symptom outcomes: 1) incident chronic bothersome LBP, and 2) incident radicular symptoms such as pain, weakness, or sensation alterations in the lower extremity.

Methods

The original LAIDBACK study followed 123 participants without current LBP or sciatica, administering standardized MRI assessments of the lumbar spine at baseline and at 3-year follow-up, and collecting information on participant-reported spine-related symptoms and signs every 4 months for 3 years. These analyses examined bivariable and multivariable associations between incident MRI findings and symptom outcomes (LBP and radicular symptoms) using logistic regression.

Results

Three-year cumulative incidence of new MRI findings ranged between 2 and 8%, depending on the finding. Incident annular fissures were associated with incident chronic LBP, after adjustment for prior back pain and depression (adjusted odds ratio [OR] 6.6; 95% confidence interval [CI] 1.2-36.9). All participants with incident disc extrusions (OR 5.4) and nerve root impingement (OR 4.1) reported incident radicular symptoms, although associations were not statistically significant. No other incident MRI findings showed large magnitude associations with symptoms.

Conclusions

Even when applying more specific definitions for spine-related symptom outcomes, few MRI findings showed large magnitude associations with symptom outcomes. Although incident annular fissures, disc extrusions, and nerve root impingement were associated with incident symptom outcomes, the 3-year incidence of these MRI findings was extremely low, and did not explain the vast majority of incident symptom cases.