MR imaging of Schmorl's nodes: Imaging characteristics and epidemio-clinical relationships

Epidemiology of Schmorl's Node in the Thoracic Spine: A Subtype Analysis

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

To describe the epidemiology of Schmorl's nodes (SN) of primarily developmental cause (SNd) and SN of primarily acquired cause (SNa) separately in the thoracic spine in subjects aged 35 to 90 years old.

SUMMARY OF BACKGROUND DATA

The epidemiology of SN and its relationship with age and gender remain controversial. On the basis of a pathophysiological hypothesis and the different morphologic characteristics, two subtypes of SN may exist and should be considered separately.

PATIENTS AND METHODS

Chest CT scans of subjects who came to our institution for health checks aged 35 to 90 years old were retrospectively reviewed. The presence or absence of SN was recorded for each thoracic vertebra. The SNs were further classified into SNd and SNa. The prevalence, location, and relationship with age, gender, and bone mineral density (BMD) were evaluated separately for the two subtypes.

RESULTS

Of the 848 subjects (407 female, mean age: 53±12.2 yr) included, 15.7% had SNs. Of the 303 SNs, 49.2% were SNd, and 48.5% were SNa. Aging increased the prevalence of SNa, while it was not related to the prevalence of SNd. Males had significantly more SNd than females (11.3% vs. 4.7%, P <0.001), while the prevalence of SNa was not different between the two genders (10.2% vs. 9.1%, P =0.666). A similar distribution of SNd and SNa among thoracic vertebral levels was appreciated, with T9 most frequently involved. Subjects with SNa had lower lumbar BMD than controls ( P =0.006), while no significant difference in BMD was found between subjects with SNd and controls ( P =0.166).

CONCLUSIONS

The clinical characteristics of SN differ based on the developmental and acquired subtypes, including the relationship with age, gender, and BMD. The subtypes may be considered distinct clinical entities as a result.

Degenerative cervical spine changes among early career fighter pilots: a 5-year follow-up

INTRODUCTION

Degenerative changes of the cervical spine often cause disability and flight duty limitations among Finnish Air Force (FINAF) fighter pilots. We aimed to study the effect of +Gz exposure on degenerative changes in the cervical spine by comparing cervical MRIs of FINAF fighter pilots and controls.

METHODS

At baseline, the volunteer study population consisted of 56 20-year-old FINAF male fighter pilots (exposure group) and 56 21-year-old Army and Navy cadets (control group). Both groups underwent MRI of the cervical spine at the baseline and after 5 years. Degenerative changes evaluated using MRI included intervertebral disc (IVD) degeneration (Pfirrmann classification), disc herniations, uncovertebral arthrosis, Schmorl's nodes, Modic changes, spinal canal stenosis, kyphosis and scoliosis.

RESULTS

The degree of IVD degeneration in the whole cervical spine increased significantly in both populations with no between-group differences. The prevalence of disc herniations also tended to increase in both populations with no difference in the incidence over the follow-up. However, pilots proved to have more disc herniations at the baseline and at the follow-up. There were virtually no between-group differences in other assessed degenerative changes.

DISCUSSION

We found that IVD degeneration and the prevalence of disc herniations increased at a similar rate for fighter pilots and non-flying military students when all cervical levels were summed up. The lack of difference may be explained by the relatively low cumulative +Gz exposure during the first 5 years of a pilots' career.

Schmorl's nodes: demystification road of endplate defects-a critical review

BACKGROUND

Schmorl's nodes (SN) were the first vertebral endplate defects described. Debate continues about their epidemiology, physiopathology, and clinical significance. The purpose of this work was to summarize and discuss available literature about SN.

METHODS

We have searched for relevant papers about SN until April 2020, with 104 articles have been reviewed.

RESULTS

More than half of the available literature described the epidemiological aspects of SN or reported rare clinical presentations and treatment options. The lack of a consensual definition of SN, among other endplate defects, contributed to difficulties in literature results' interpretation. Summing up, SN is a frequent vertebral defect at the thoracolumbar juncture, with ethnic and gender influence. Lumbar Schmorl's nodes were frequently associated with disc degenerative disease and back pain. Their physiopathology remains unknown. However, strain energy changes in the spine along with morphological aspects of the vertebra, the genetic background, and the osteoimmunology may constitute possible clues. New SN could be confused in malignancy context with bone metastasis. The literature describes some imaging techniques to differentiate them, avoiding invasive approaches. Treatment options for rare painful presentations remain few with low evidence. Further studies are needed to establish a consensual definition for SN, understand clinical aspects, and provide adequate therapeutic strategies.

Associations between clinical neck symptoms and various evaluations ofcervical intervertebral disc degeneration by magnetic resonance imaging

PURPOSE

Magnetic resonance imaging (MRI) is widely used to evaluate intervertebral disc degeneration. Recently, various evaluations of cervical disc degeneration using MRI have been conducted, but there is no gold standard. The purpose of this study was to compare the reproducibilities of previously reported classifications for evaluating cervical disc degeneration by MRI and their associations with clinical symptoms.

PARTICIPANTS AND METHODS

A total of 582 subjects underwent conventional MRI of the cervical spine. Disc degeneration was assessed in each intervertebral disc from C2/3 to C7/T1 using five different classifications: Matsumoto's grading system, Miyazaki's grading system, Nakashima's grading system, Jacobs' grading system, and Suzuki's grading system. MR images of 30 participants were used, and Cohen's kappa coefficient of agreement of each classification was calculated for intra-observer and inter-observer reliabilities. These five classifications of disc degeneration and changes of vertebral endplates were measured, and associations with clinical symptoms were assessed.

RESULTS

Kappa (κ) values of intra-observer agreement were higher for Jacobs' classification, whereas those of inter-observer agreement were higher for Nakashima's and Jacobs' classifications than for other classifications. The prevalences of neck pain and shoulder stiffness were 27.4% and 41.9%, respectively. There were no associations for any classifications of disc degeneration and Modic types with neck pain or shoulder stiffness. Only the presence of Schmorl's nodes was associated with neck pain.

CONCLUSION

At present, there is no specific classification for cervical disc degeneration associated with clinical symptoms. Vertebral endplate changes might be associated with clinical symptoms. It may be necessary to create a new classification for better reproducibility of the evaluation of cervical disc degeneration.

Classification of certain vertebral degenerations using MRI image features

BACKGROUND AND OBJECTIVE

This article describes a fully automatic system for classifying various spinal degenerative phenotypes namely Modic changes, endplate defects and focal changes which are associated with lower back pain. These are obtained from T1/T2 Magnetic Resonance Imaging (MRI) scans. Lower back pain is a predominantly occurring ailment, which is prone to have various roots including the anatomical and pathophysciological aspects. Clinicians and radiologist use MRI to assess and evaluate the extent of damage, cause, and to decide on the future course of treatment. In large healthcare systems, to circumvent the manual reading of various image slices, we describe a system to automate the classification of various vertebral degeneracies that cause lower back pain.

METHODS

We implement a combination of feature extraction, image analysis based on geometry and classification using machine learning techniques for identifying vertebral degeneracies. Image features like local binary pattern, Hu's moments and gray level co-occurrence matrix (GLCM) based features are extracted to identify Modic changes, endplate defects, and presence of any focal changes. A combination of feature set is used for describing the extent of Modic change on the end plate. Feature sensitivity studies towards efficient classification is presented. A STIR based acute/chronic classification is also attempted in the current work.

RESULTS

The implemented method is tested and validated over a dataset containing 100 patients. The proposed framework for detecting the extent of Modic change achieves an accuracy of 85.91%. From the feature sensitivity analysis, it is revealed that entropy based measure obtained from gray level co-occurrence matrix alone is sufficient for detection of focal changes. The classification performance for detecting endplate defect is highly sensitive to the first 2 Hu's moments.

CONCLUSION

A novel approach to identify the allied vertebral degenerations and extent of Modic changes in vertebrae by exploiting image features and classification through machine learning is proposed. This shall assist radiologists in detecting abnormalities and in treatment planning.

Axial Spondyloarthritis: Mimics and Pitfalls of Imaging Assessment

Axial spondyloarthritis (axSpA) is a chronic inflammatory disorder that predominantly involves the axial skeleton. Imaging findings of axSpA can be divided into active changes, which include bone marrow edema, synovitis, enthesitis, capsulitis, and intra-articular effusion, and structural changes, which include erosions, sclerosis, bone fatty infiltration, fat deposition in an erosion cavity, and bone bridging or ankylosis. The ability to distinguish between imaging lesions suggestive of axSpA and artifacts or lesions suggestive of other disorders is critical for the accurate diagnosis of axSpA. Diagnosis may be challenging, particularly in early-stage disease and magnetic resonance imaging (MRI) plays a key role in the detection of subtle or inflammatory changes. MRI also allows the detection of structural changes in the subchondral bone marrow that are not visible on conventional radiography and is of prognostic and monitoring value. However, bone structural changes are more accurately depicted using computed tomography. Conventional radiography, on the other hand, has limitations, but it is easily accessible and may provide insight on gross changes as well as rule out other pathological features of the axial skeleton. This review outlines the imaging evaluation of axSpA with a focus on imaging mimics and potential pitfalls when assessing the axial skeleton.

Cervical Spine Endplate Abnormalities and Association With Pain, Disability, and Adjacent Segment Degeneration After Anterior Cervical Discectomy and Fusion

STUDY DESIGN

A retrospective study with prospectively-collected data.

OBJECTIVE

To determine how type, location, and size of endplate lesions on magnetic resonance imaging (MRI) may be associated with symptoms and clinical outcomes after anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

Structural endplate abnormalities are important, yet understudied, phenomena in the cervical spine. ACDF is a common surgical treatment for degenerative disc disease; however, adjacent segment degeneration/disease (ASD) may develop.

METHODS

Assessed the imaging, symptoms and clinical outcomes of 861 patients who underwent ACDF at a single center. MRI and plain radiographs of the cervical spine were evaluated. Endplate abnormalities on MRI were identified and stratified by type (atypical, typical), location, relation to operative levels, presence at the adjacent level, and size. These strata were assessed for association with presenting symptoms, patient-reported, and postoperative outcomes.

RESULTS

Of 861 patients (mean follow-up: 17.4 months), 57.3% had evidence of endplate abnormalities, 39.0% had typical abnormalities, while 18.2% had atypical abnormalities. Patients with any endplate abnormality had greater odds of myelopathy irrespective of location or size, while sensory deficits were associated with atypical lesions (P = 0.016). Typical and atypical abnormalities demonstrated differences in patient-reported outcomes based on location relative to the fused segment. Typical variants were not associated with adverse surgical outcomes, while atypical lesions were associated with ASD (irrespective of size/location; P = 0.004) and reoperations, when a large abnormality was present at the proximal adjacent level (P = 0.025).

CONCLUSION

This is the first study to examine endplate abnormalities on MRI of the cervical spine, demonstrating distinct risk profiles for symptoms, patient-reported, and surgical outcomes after ACDF. Patients with typical lesions reported worsening postoperative pain/disability, while those with atypical abnormalities experienced greater rates of ASD and reoperation. This highlights the relevance of a degenerative spine phenotypic assessment, and suggests endplate abnormalities may prognosticate clinical outcomes after surgery.

LEVEL OF EVIDENCE

3.

The effect of bone mineral density on development of Schmorl's nodes in young patients

OBJECTIVE

The aim of this study was to detect the relationship between the development of Schmorl's nodes (SNs) and bone mineral density (BMD) in young patients.

METHODS

Computerized tomography (CT) images of the thoracolumbar vertebral column were retrospectively examined by two experienced radiologists for SNs. The diagnostic criterion for SN was defined as a node size larger than one-third but not more than two-thirds of the relevant vertebral endplate. Considering the eligibility criteria, a total of 74 individuals (60 males and 14 females; mean age: 24.3 years; age range: 18-40 years) with SN at the thoracolumbar vertebrae were included in the patient group, and a total of 38 age- and gender-matched individuals (30 males and 8 females; mean age: 25 years) with no evidence of SN were included in the control group. All these individuals were younger than 40 years. In the patient group, SNs were assessed in terms of the distribution of the thoracolumbar vertebrae, the location of the upper and lower endplates, and the total number of lesions. In all individuals included in the study, BMD was measured from the axial CT sections by quantitative CT and then compared between the two groups.

RESULTS

The distribution of age and gender was comparable between the two groups (p=0.438). A total of 208 SNs were identified in the patient group. Of these, 92 (44%) were located at the thoracic vertebrae and 116 (56%) at the lumbar vertebrae. The mean BMD was 131.6 g/cm3 in the patient group and 140.7 g/cm3 in the control group (p=0.03). There was no significant relationship between the total number of SNs per patient and the mean BMD (p=0.156).

CONCLUSION

Evidence from this study revealed that low BMD may be a predisposing factor for the development of SNs in patients younger than 40 years.

LEVEL OF EVIDENCE

Level III, Diagnostic Study.

Abnormal Conditions of the Diskovertebral Segment: MRI With Anatomic-Pathologic Correlation

OBJECTIVE. The purpose of this article is to review the appearance of various abnormalities that affect the lumbar intervertebral disk and diskovertebral segment through anatomic-pathologic correlation in cadavers. CONCLUSION. Familiarity with the pathologic conditions in and around the intervertebral disk is important in recognizing such conditions as a potential source of symptoms. We revisit the principal role of MRI in evaluating these abnormalities and excluding other sources of significant clinical manifestations.

Lumbar spine Schmorl's nodes; prevalence in adults with back pain, and their relation to vertebral endplate degeneration

Background

In 1927, Schmorl described a focal herniation of disc material into the adjacent vertebral body through a defect in the endplate, named as Schmorl’s node (SN). The aim of the study is to reveal the prevalence and distribution of Schmorl’s nodes (SNs) in the lumbar spine and their relation to disc degeneration disease in Kirkuk city population.

Results

A cross-sectional analytic study was done for 324 adults (206 females and 118 males) with lower back pain evaluated as physician requests by lumbosacral MRI at the Azadi Teaching Hospital, Kirkuk city, Iraq. The demographic criteria of the study sample were 20–71 years old, 56–120 kg weight, and 150–181 cm height. SNs were seen in 72 patients (22%). Males were affected significantly more than the females (28.8% vs. 18.8%, P = 0.03). SNs were most significantly affecting older age groups. L1–L2 was the most affected disc level (23.6%) and the least was L5–S1 (8.3%). There was neither a significant relationship between SN and different disc degeneration scores (P = 0.76) nor with disc herniation (P = 0.62, OR = 1.4), but there was a significant relation (P = 0.00001, OR = 7.9) with MC.

Conclusion

SN is a frequent finding in adults’ lumbar spine MRI, especially in males; it is related to vertebral endplate bony pathology rather than discal pathology.

Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study

BACKGROUND CONTEXT

The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP.

PURPOSE

To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II).

STUDY DESIGN

A prospective comparative study.

PATIENT SAMPLE

Two hundred patients were enrolled: 96 in Group I and 104 in Group II.

OUTCOME MEASURES

Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records.

METHODS

Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest.

RESULTS

The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this score rises to 7.02, indicative of a high sensitivity.

CONCLUSIONS

Single-photon emission computerized tomography with computerized tomography might have potential in the diagnostic workup of patients with ns CLBP, owing to its higher sensitivity when compared with other advanced medical imaging modalities.