Tidemark Avulsions are a Predominant Form of Endplate Irregularity

The Effectiveness of Intraosseous Basivertebral Nerve Radiofrequency Ablation for the Treatment of Vertebrogenic Low Back Pain: An Updated Systematic Review with Single-Arm Meta-analysis

OBJECTIVE

To provide an estimate of the effectiveness of basivertebral nerve (BVN) radiofrequency ablation (RFA) to treat vertebrogenic low back pain (LBP).

DESIGN

Systematic review with single-arm meta-analysis.

POPULATION

Persons ≥18 years of age with chronic LBP associated with type 1 or 2 Modic changes.

INTERVENTION

Intraosseous BVN RFA.

COMPARISON

Sham, placebo procedure, active standard care treatment, or none.

OUTCOMES

The proportion of patients treated with BVN RFA who reported ≥50% pain score improvement on a visual analog scale or numeric rating scale. The main secondary outcome was ≥15-point improvement in Oswestry Disability Index score.

METHODS

Three reviewers independently assessed articles published before December 6, 2021, in MEDLINE and Embase. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) framework was used to evaluate the overall quality of evidence.

RESULTS

Of the 856 unique records screened, 12 publications met the inclusion criteria, representing six unique study populations, with 414 participants allocated to receive BVN RFA. Single-arm meta-analysis showed a success rate of 65% (95% confidence interval [CI] 51-78%) and 64% (95% CI 43-82%) for ≥50% pain relief at 6 and 12 months, respectively. Rates of ≥15-point Oswestry Disability Index score improvement were 75% (95% CI 63-86%) and 75% (95% CI 63-85%) at 6 and 12 months, respectively.

CONCLUSION

According to GRADE, there is moderate-quality evidence that BVN RFA effectively reduces pain and disability in most patients with vertebrogenic LBP. Further high-quality studies will likely improve our understanding of the effectiveness of this procedure.

Magnetic Resonance Imaging Characteristics Associated with Treatment Success from Basivertebral Nerve Ablation: An Aggregated Cohort Study of Multicenter Prospective Clinical Trials Data

OBJECTIVE

Investigate associations between endplate and motion segment magnetic resonance imaging (MRI) characteristics and treatment outcomes following basivertebral nerve radiofrequency ablation (BVN RFA) in patients with clinically suspected vertebral endplate pain (VEP).

DESIGN

Aggregated cohort study of 296 participants treated with BVN RFA from three prospective clinical trials.

METHODS

Baseline MRI characteristics were analyzed using stepwise logistic regression to identify factors associated with treatment success. Predictive models used three definitions of treatment success: (1) ≥50% low back pain (LBP) visual analog scale (VAS), (2) ≥15-point Oswestry Disability Index (ODI), and (3) ≥50% VAS or ≥15-point ODI improvements at 3-months post-BVN RFA.

RESULTS

The presence of lumbar facet joint fluid (odds ratio [OR] 0.586) reduced the odds of BVN RFA treatment success in individuals with clinically suspected VEP. In patients with a less advanced degenerative disc disease (DDD) profile, a > 50% area of the endplate with bone marrow intensity changes (BMIC) was predictive of treatment success (OR 4.689). Both regressions areas under the curve (AUCs) were under 70%, indicating low predictive value. All other vertebral endplate, intervertebral disc, nerve roots facet joint, spinal segmental alignment, neuroforamina, lateral recesses, and central canal MRI characteristics were not associated with BVN RFA success.

CONCLUSIONS

In patients with vertebrogenic low back pain with Modic changes, the presence of degenerative findings of the anterior and posterior column was not associated with a clinically important impact on BVN RFA treatment success. None of the models demonstrated strong predictive value, indicating that the use of objective imaging biomarkers (Type 1 and/or 2 Modic changes) and a correlating presentation of pain remain the most useful patient selection factors for BVN RFA.

Diagnostic Role of Magnetic Resonance Imaging in Low Back Pain Caused by Vertebral Endplate Degeneration

Low back pain (LBP) is a common health issue worldwide with a huge economic burden on healthcare systems. In the United States alone, the cost is estimated to be $100 billion each year. Intervertebral disc degeneration is considered one of the primary causes of LBP. Moreover, the critical role of the vertebral endplates in disc degeneration and LBP is becoming apparent. Endplate abnormalities are closely correlated with disc degeneration and pain in the lumbar spine. Imaging modalities such as plain film radiography, computed tomography, and fluoroscopy are helpful but not very effective in detecting the causes behind LBP. Magnetic resonance imaging (MRI) can be used to acquire high-quality three-dimensional images of the lumbar spine without using ionizing radiation. Therefore, it is increasingly being used to diagnose spinal disorders. However, according to the American College of Radiology, current referral and justification guidelines for MRI are not sufficiently clear to guide clinical practice. This review aimed to evaluate the role of MRI in diagnosing LBP by considering the correlative contributions of vertebral endplates. The findings of the review indicate that MRI allows for fine evaluations of endplate morphology, endplate defects, diffusion and perfusion properties of the endplate, and Modic changes. Changes in these characteristics of the endplate were found to be closely correlated with disc degeneration and LBP. The collective evidence from the literature suggests that MRI may be the imaging modality of choice for patients suffering from LBP. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 3.

Development of a standardized histopathology scoring system for human intervertebral disc degeneration: an Orthopaedic Research Society Spine Section Initiative

BACKGROUND

Histopathological analysis of intervertebral disc (IVD) tissues is a critical domain of back pain research. Identification, description, and classification of attributes that distinguish abnormal tissues form a basis for probing disease mechanisms and conceiving novel therapies. Unfortunately, lack of standardized methods and nomenclature can limit comparisons of results across studies and prevent organizing information into a clear representation of the hierarchical, spatial, and temporal patterns of IVD degeneration. Thus, the following Orthopaedic Research Society (ORS) Spine Section Initiative aimed to develop a standardized histopathology scoring scheme for human IVD degeneration.

METHODS

Guided by a working group of experts, this prospective process entailed a series of stages that consisted of reviewing and assessing past grading schemes, surveying IVD researchers globally on current practice and recommendations for a new grading system, utilizing expert opinion a taxonomy of histological grading was developed, and validation performed.

RESULTS

A standardized taxonomy was developed, which showed excellent intra-rater reliability for scoring nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous end plate (CEP) regions (interclass correlation [ICC] > .89). The ability to reliably detect subtle changes varied by IVD region, being poorest in the NP (ICC: .89-.95) where changes at the cellular level were important, vs the AF (ICC: .93-.98), CEP (ICC: .97-.98), and boney end plate (ICC: .96-.99) where matrix and structural changes varied more dramatically with degeneration.

CONCLUSIONS

The proposed grading system incorporates more comprehensive descriptions of degenerative features for all the IVD sub-tissues than prior criteria. While there was excellent reliability, our results reinforce the need for improved training, particularly for novice raters. Future evaluation of the proposed system in real-world settings (eg, at the microscope) will be needed to further refine criteria and more fully evaluate utility. This improved taxonomy could aid in the understanding of IVD degeneration phenotypes and their association with back pain.

Intervertebral disc degeneration and regeneration: a motion segment perspective

Back and neck pain have become primary reasons for disability and healthcare spending globally. While the causes of back pain are multifactorial, intervertebral disc degeneration is frequently cited as a primary source of pain. The annulus fibrosus (AF) and nucleus pulposus (NP) subcomponents of the disc are common targets for regenerative therapeutics. However, disc degeneration is also associated with degenerative changes to adjacent spinal tissues, and successful regenerative therapies will likely need to consider and address the pathology of adjacent spinal structures beyond solely the disc subcomponents. This review summarises the current state of knowledge in the field regarding associations between back pain, disc degeneration, and degeneration of the cartilaginous and bony endplates, the AF-vertebral body interface, the facet joints and spinal muscles, in addition to a discussion of regenerative strategies for treating pain and degeneration from a whole motion segment perspective.

Damage to the human lumbar cartilage endplate and its clinical implications

The cartilaginous endplate (CEP) is a thin layer of hyaline cartilage, and plays an important role in the diffusion of nutrients into the intervertebral discs. Its damage may seriously affect the disc degeneration, and result in low back pain (LBP). However, the structural features of damaged CEPs have not been well characterized, and this hinders our understanding of the etiology of disc degeneration and pain. To present the structural features of micro-damaged CEPs in patients with disc degeneration and LBP that might even be regarded as an initial factor for disc degeneration, we performed a histological study of micro-damaged CEPs harvested from human lumbar intervertebral discs and analyzed its clinical implications. Human lumbar CEPs were excised from 35 patients (mean age 60.91 years) who had disc degeneration and LBP. Control tissue was obtained from 15 patients (mean age 54.67 years) with lumbar vertebral burst fractures. LBP and disability were assessed clinically, and all patients underwent anterior vertebral body fusion surgery. CEPs together with some adjacent nucleus pulposus (NP) were sectioned at 4 µm, and stained using H&E, Safranin O/Fast Green, and Alcian Blue. Immunostaining and PCR were used to identify various markers of degeneration, innervation, and inflammation. Histology demonstrated physical micro-damage in 14/35 CEPs from the disc degeneration group. Six major types of damage could be distinguished: fissure, traumatic nodes, vascular mimicry, incorporation of NP tissue within the CEP, incorporation of bone within the CEP, and incorporation of NP and bone within the CEP. Pain and disability scores (ODI: p = 0.0190; JOA: p = 0.0205; JOABPEQ: p = 0.0034) were significantly higher in those with micro-damaged CEPs (N = 14) than in those with non-damaged CEPs (N = 21). CEP damage was significantly associated with elevated MMP3 (p = 0.043), MMP13 (p = 0.0191), ADAMTS5 (p = 0.0253), TNF-α (p = 0.0011), and Substance P (p = 0.0028), and with reduced Sox9 (p = 0.0212), aggrecan (p = 0.0127), and type II collagen (p = 0.0139). In conclusion, we presented a new classification of human lumbar micro-damaged CEPs. Furthermore, we verify disc degeneration, innervation, and discogenic pain in micro-damaged CEPs.

Degeneration alters structure-function relationships at multiple length-scales and across interfaces in human intervertebral discs

Intervertebral disc (IVD) degeneration and associated back pain place a significant burden on the population. IVD degeneration is a progressive cascade of cellular, compositional, and structural changes, which results in a loss of disc height, disorganization of extracellular matrix architecture, tears in the annulus fibrosus which may involve herniation of the nucleus pulposus, and remodeling of the bony and cartilaginous endplates (CEP). These changes to the IVD often occur concomitantly, across the entire motion segment from the disc subcomponents to the CEP and vertebral bone, making it difficult to determine the causal initiating factor of degeneration. Furthermore, assessments of the subcomponents of the IVD have been largely qualitative, with most studies focusing on a single attribute, rather than multiple adjacent IVD substructures. The objective of this study was to perform a multiscale and multimodal analysis of human lumbar motion segments across various length scales and degrees of degeneration. We performed multiple assays on every sample and identified several correlations between structural and functional measurements of disc subcomponents. Our results demonstrate that with increasing Pfirrmann grade there is a reduction in disc height and nucleus pulposus T2 relaxation time, in addition to alterations in motion segment macromechanical function, disc matrix composition and cellular morphology. At the cartilage endplate-vertebral bone interface, substantial remodeling was observed coinciding with alterations in micromechanical properties. Finally, we report significant relationships between vertebral bone and nucleus pulposus metrics, as well as between micromechanical properties of the endplate and whole motion segment biomechanical parameters, indicating the importance of studying IVD degeneration as a whole organ.

Lumbar Vertebral Endplate Defects on Magnetic Resonance Imaging in Degenerative Spondylolisthesis: Novel Classification, Characteristics, and Correlative Factor Analysis

BACKGROUND

Endplate defects are commonly seen in patients with lumbar degenerative disease. However, little is known about the presence of endplate defects in patients with degenerative spondylolisthesis (DS). In the present study, we have introduced a classification system for endplate defects in patients with DS using routine magnetic resonance imaging findings and explored the correlative factors.

METHODS

Endplate defects were classified into 3 major categories (rim defects, focal defects, and erosive defects) and 5 subtypes (anterior type, posterior type, arc type at the anterior rim, notch type, and Schmorl's nodes). The incidence rates of the endplate defects were compared between the slippage and nonslippage levels. The correlations between the endplate defects and age, sex, disc degeneration, Modic changes (MCs), body mass index, slippage segment, and slippage degree were analyzed.

RESULTS

Endplate defects were present in 47.43% of the endplates in DS. The most common endplate defects were rim defects. The occurrence of endplate defects, especially anterior defects, was more common at the slippage levels. Endplate defects were associated with age and closely related to MCs and the severity of disc degeneration. The slippage degree, slippage segment, body mass index, and sex differences were not associated with endplate defects in our study. The results obtained using this novel classification system were stable and consistent.

CONCLUSIONS

The results from the present study have shown that the novel radiological classification system of endplate defects is reliable. Endplate defects were associated with slippage but not with the slippage degree or slippage segment differences in DS. The correlation between endplate defects and age and between MCs and disc degeneration were important features on the magnetic resonance imaging scans of patients with DS.

Association of vertebral endplate microstructure with bone strength in men and women

Epidemiological and biomechanical evidence indicates that the risk of vertebral fracture differs between men and women, and that vertebral fracture frequently involves failure of the endplate region. The goal of this study was to compare the bone microstructure of the endplate region-defined as the (bony) vertebral endplate and underlying subchondral trabecular bone-between sexes and to determine whether any such sex differences are associated with vertebral strength. The bone density (volume fraction, apparent density and tissue mineral density) of the superior-most 2 mm of the vertebra, and the bone density and trabecular architecture of the next 5 mm were quantified using micro-computed tomography in human T8 (12 female, 16 male) and L1 (13 female, 12 male) vertebrae. Average density of the vertebra (integral bone mineral density (BMD)) was determined by quantitative computed tomography and compressive strength by mechanical testing. Few differences were found between male and female vertebrae in the density of the endplate region; none were found in trabecular architecture. However, whereas endplate volume fraction was positively correlated with integral BMD in male vertebrae (r = 0.654, p < .001), no correlation was found in the female vertebrae (r = 0.157, p = .455). Accounting for the density of the endplate region improved predictions of vertebral strength (p < .034) and eliminated sex-specificity in the strength prediction that was based on integral BMD alone. These results suggest that the density of the endplate region influences vertebral fracture and that non-invasive assessment of this region's density can contribute to predictions of vertebral strength in men and women.

Infectious Spondylitis Mimics: Mechanisms of Disease and Imaging Findings

Infectious processes of the spine are on the rise; in this scenario recognition of entities imitating infection is very important. The discovertebral unit is regarded as one of the most important and active sites in the spine. Importantly, the vertebral bony rim and the anterior corners of the vertebral bodies have significant vascularization, they are the last regions to ossify in the developmental process and suffer mechanical forces. Early septic or aseptic discitis-osteomyelitis, properly called spondylitis, involves these anterior regions. Early degeneration is characterized by disc desiccation; however, there is preferential involvement for the corners of the vertebral bodies as well. Many entities to include degenerative changes, inflammatory spondyloarthropathies, neuropathic spine, or pseudo arthrosis, among others, affect the discovertebral unit and can imitate infection. With some exceptions, important imaging findings for the identification of an infectious mimic include the absence of soft tissue enhancement or fluid collections in the paraspinal or epidural regions, and the involvement of multiple levels or the posterior elements. We review developmental, anatomical, and pathologic concepts correlating with imaging clues. Overall, our goal is to increase awareness and to improve recognition of mimicking entities.

Contribution of the endplates to disc degeneration

Purpose of review

The endplates form the interface between the rigid vertebral bodies and compliant intervertebral discs. Proper endplate function involves a balance between conflicting biomechanical and nutritional demands. This review summarizes recent data that highlight the importance of proper endplate function and the relationships between endplate dysfunction, adjacent disc degeneration, and axial low back pain.

Recent findings

Changes to endplate morphology and composition that impair its permeability associate with disc degeneration. Endplate damage also associates with disc degeneration, and the progression of degeneration may be accelerated and the chronicity of symptoms heightened when damage coincides with evidence of adjacent bone marrow lesions.

Summary

The endplate plays a key role in the development of disc degeneration and low back pain. Clarification of the mechanisms governing endplate degeneration and developments in clinical imaging that enable precise evaluation of endplate function and dysfunction will distinguish the correlative vs. causative nature of endplate damage and motivate new treatments that target pathologic endplate function.