Imaging of spinal stenosis: neurogenic intermittent claudication and cervical spondylotic myelopathy

The MRI of Lumbar Vertebral Canal in Low Back Pain: A Cross-Sectional Study

Background The imaging of the lumbar canal is an important aspect of low back pain (LBP) management. Magnetic resonance imaging (MRI) has gained widespread acceptance for the evaluation of spine anatomy. Objective The objective of the study is to compare the MRI findings of the anteroposterior diameter, transverse diameter, and thecal sac area of the lumbar vertebral canal in symptomatic low back pain patients to that of patients without low back pain. Methods The cross-sectional study included 200 subjects of which 100 subjects (49 males and 51 females) were symptomatic cases of low back pain and 100 subjects (53 males and 47 females) had no symptoms of low back pain and were enrolled as controls. The MRI scans were studied for the anteroposterior diameter, transverse diameter, and thecal sac area of the lumbar vertebral canal. Results In our study, the anteroposterior diameter of the lumbar vertebral canal among cases was found to have a mean of 14.42, 14.09, 13.44, 13.63, and 13.79 with a standard deviation (SD) of 1.25, 1.32, 1.75, 1.75, and 2.65 at L1, L2, L3, L4, and L5 levels, respectively. The anteroposterior diameter of the lumbar vertebral canal among controls was found to have a mean of 15.26, 15.16, 14.71, 14.68, and 15.28 with an SD of 1.60, 1.67, 1.30, 1.36, and 1.97 at L1, L2, L3, L4, and L5 levels, respectively. The difference in anteroposterior diameters of the lumbar vertebral canal was found to be statistically significant at each level, between cases and controls. The transverse diameter of the vertebral canal was found to be smaller in cases as compared to controls with a statistically significant difference at each of the levels studied. The thecal sac area of the vertebral canal was found to be less in subjects with low back pain at each of the vertebral levels studied. Conclusion The study results provide insight into the lumbar vertebral parameters in the study population and give comparative data among the symptomatic low back pain patients and control subjects without low back pain. The MRI reflected decreased anteroposterior diameter, transverse diameter, and thecal sac area of the lumbar vertebral canal among symptomatic low back pain patients.

Neuroimaging of Spinal Cord and Cauda Equina Disorders

PURPOSE OF REVIEW

This article reviews the neuroimaging of disorders of the spinal cord and cauda equina, with a focus on MRI. An anatomic approach is used; diseases of the extradural, intradural-extramedullary, and intramedullary (parenchymal) compartments are considered, and both neoplastic and non-neoplastic conditions are covered. Differentiating imaging features are highlighted.

RECENT FINDINGS

Although T2-hyperintense signal abnormality of the spinal cord can have myriad etiologies, neuroimaging can provide specific diagnoses or considerably narrow the differential diagnosis in many cases. Intradural-extramedullary lesions compressing the spinal cord have a limited differential diagnosis and are usually benign; meningiomas and schwannomas are most common. Extradural lesions can often be specifically diagnosed. Disk herniations are the most commonly encountered mass of the epidural space. Cervical spondylotic myelopathy can cause a characteristic pattern of enhancement, which may be mistaken for an intrinsic myelopathy. A do-not-miss diagnosis of the extradural compartment is idiopathic spinal cord herniation, the appearance of which can overlap with arachnoid cysts and webs. Regarding intrinsic causes of myelopathy, the lesions of multiple sclerosis are characteristically short segment but can be confluent when multiple. Postcontrast MRI can be particularly helpful, including when attempting to differentiate the long-segment myelopathy of neurosarcoidosis and aquaporin-4 (AQP4)-IgG-seropositive neuromyelitis optica spectrum disorder (NMOSD) and when characterizing spinal cord tumors such as primary neoplasms and metastases. Spinal dural arteriovenous fistula is another do-not-miss diagnosis, with characteristic MRI features both precontrast and postcontrast. Tract-specific white matter involvement can be a clue for diseases such as subacute combined degeneration, paraneoplastic myelopathy, and radiation myelitis, whereas gray matter-specific involvement can suggest conditions such as cord infarct, viral myelitis, or myelin oligodendrocyte glycoprotein (MOG)-IgG associated disorder.

SUMMARY

Knowledge of the neuroimaging findings of the many causes of spinal cord and cauda equina dysfunction is critical for both neurologists and neuroradiologists. A structured approach to lesion compartmental location and imaging feature characterization is recommended.

Long-term clinical and magnetic resonance imaging follow-up of dogs with osseous-associated cervical spondylomyelopathy

BACKGROUND

Osseous-associated cervical spondylomyelopathy (OA-CSM) is a complex disorder with limited long-term survival. The longitudinal progression is currently unknown.

OBJECTIVE

To describe changes on magnetic resonance imaging (MRI) over a 2-year minimum period. We hypothesized that spinal lesions would progress in the majority of dogs.

ANIMALS

Eleven dogs previously diagnosed with OA-CSM were prospectively studied. Nine dogs were treated medically, whereas 2 were treated surgically.

METHODS

Clinical and MRI follow-up were performed with a median time between MRI studies of 30 months (range, 24-54). Morphologic assessment evaluated vertebral canal stenosis, spinal cord compression, foraminal stenosis, and articular processes, among other variables. Morphometric assessment included vertebral canal area, spinal cord area, area of the articular processes, and foraminal height.

RESULTS

On follow-up MRI, the most affected site at the initial examination in medically treated dogs had progressed in 4 of 9 dogs, improved in 4, and was unchanged in 3. Clinically, all dogs except 2 medically treated dogs were unchanged to improve at follow-up. Initially, 50 of 60 (83.3%) intervertebral spaces had vertebral canal stenosis, whereas in the follow-up MRI 82.3% did. Of the sites with stenosis, 45.7% were unchanged, 18.6% improved, and 38.9% worsened. Morphometry identified significant decreases in vertebral canal and spinal cord areas at C4-C5 through C6-C7, and significant progression of articular process irregularities at C3-C4 and C6-C7.

CONCLUSIONS AND CLINICAL IMPORTANCE

This long-term follow-up study of dogs with OA-CSM did not identify clinical or MRI progression of lesions in the majority of dogs.

Current Evidence for Diagnosis of Common Conditions Causing Low Back Pain: Systematic Review and Standardized Terminology Recommendations

OBJECTIVE

The purpose of this systematic review is to evaluate and summarize current evidence for diagnosis of common conditions causing low back pain and to propose standardized terminology use.

METHODS

A systematic review of the scientific literature was conducted from inception through December 2018. Electronic databases searched included PubMed, MEDLINE, CINAHL, Cochrane, and Index to Chiropractic Literature. Methodological quality was assessed with the Scottish Intercollegiate Guidelines Network checklists.

RESULTS

Of the 3995 articles screened, 36 (8 systematic reviews and 28 individual studies) met final eligibility criteria. Diagnostic criteria for identifying likely discogenic, sacroiliac joint, and zygapophyseal (facet) joint pain are supported by clinical studies using injection-confirmed tissue provocation or anesthetic procedures. Diagnostic criteria for myofascial pain, sensitization (central and peripheral), and radicular pain are supported by expert consensus-level evidence. Criteria for radiculopathy and neurogenic claudication are supported by studies using combined expert-level consensus and imaging findings.

CONCLUSION

The absence of high-quality, objective, gold-standard diagnostic methods limits the accuracy of current evidence-based criteria and results in few high-quality studies with a low risk of bias in patient selection and reference standard diagnosis. These limitations suggest practitioners should use evidence-based criteria to inform working diagnoses rather than definitive diagnoses for low back pain. To avoid the unnecessary complexity and confusion created by multiple overlapping and nonspecific terms, adopting International Association for the Study of Pain terminology and definitions is recommended.

Neurogenic Claudication: a Review of Current Understanding and Treatment Options

PURPOSE OF REVIEW

With an aging population and increased prevalence of the disease, we set out to evaluate the validity of current diagnostic criteria for neurogenic claudication as well as the efficacy of the treatment options for the main cause, lumbar spinal stenosis (LSS).

RECENT FINDINGS

Epidural steroid injections (ESI) were most efficacious when the injectate is a steroid combined with lidocaine or lidocaine only. There are promising results regarding the efficacy of the minimally invasive lumbar decompression (MILD) procedure as well as interspinous process spacers (IPS) compared to surgical alternatives. Spinal cord stimulators are gaining ground as an effective alternative to surgery in patients with lumbar spinal stenosis that is not responsive to conservative measures or epidural injections. We found that there continues to be a lack of consensus on the diagnostic criteria, management, and treatment options for patients with LSS. The Delphi consensus is the most current recommendation to assist clinicians with making the diagnosis. Physical therapy, NSAIDs, gabapentin, and other conservative therapy measures are unproven in providing long-lasting relief. In patients with radicular symptoms, an ESI may be indicated when a combination of lidocaine with steroids is used or using lidocaine alone. In addition, there is not enough high-quality evidence to make a recommendation regarding the use of MILD versus interspinous spacers for neurogenic claudication. There remains a need for high-quality evidence regarding the efficacy of different conservative treatments, interventional procedures, and surgical outcomes in patients with neurogenic claudication in LSS.

Achondroplasia: a comprehensive clinical review

Achondroplasia is the most common of the skeletal dysplasias that result in marked short stature (dwarfism). Although its clinical and radiologic phenotype has been described for more than 50 years, there is still a great deal to be learned about the medical issues that arise secondary to this diagnosis, the manner in which these are best diagnosed and addressed, and whether preventive strategies can ameliorate the problems that can compromise the health and well being of affected individuals. This review provides both an updated discussion of the care needs of those with achondroplasia and an exploration of the limits of evidence that is available regarding care recommendations, controversies that are currently present, and the many areas of ignorance that remain.

Prevalence of degenerative changes and overlap with spondyloarthritis-associated lesions in the spine of patients from the DESIR cohort

Objectives

To describe the prevalence of degenerative changes on MRI and conventional radiographs of the spine in a young population with suspicion of axial spondyloarthritis (axSpA) and assess whether it is possible to discriminate between degenerative changes and lesions associated with axSpA.

Methods

Whole spine MRI and cervical and lumbar radiographs of patients ≥18 years with chronic back pain (≥3 months, ≤3 years, onset <50 years) were assessed for degeneration by two readers, and for SpA lesions by two other readers, all blinded for clinical information and results of the other readers. Degenerative scores were adjudicated in case of disagreement (by a third reader). Patients fulfilling and not fulfilling the Assessment of SpondyloArthritis international Society axSpA criteria were compared for prevalence of degenerative lesions. Scores for degenerative and SpA lesions were compared, and overlap was defined as the presence of both types of lesions in a single vertebral unit (VU).

Results

In 456/648 (70.4%) patients (46.8% men, mean age 33.6), degenerative lesions were found with similar percentages in patients with no axSpA and with axSpA (72.4% and 69.2%, p=0.45). Modic changes were found more often in patients with no axSpA (29/239, 12.1%) versus patients with axSpA (19/409, 4.6%, p=0.01). Other lesions were evenly distributed. Overlap was minimal in 19 patients (3.0%) and 32/14 674 (0.2%) VUs for SpA reader 1 and in 23 patients (3.6%) and 34/14 674 VUs (0.2%) for SpA reader 2.

Conclusion

The prevalence of degeneration is high in an early inflammatory back pain cohort. Discrimination between degeneration and axSpA lesions is very well possible with little overlap between degenerative and axSpA readings.

Diffusion tensor imaging in the musculoskeletal and peripheral nerve systems: from experimental to clinical applications

Magnetic resonance imaging (MRI) is a well-established imaging modality which is used in all districts of the musculoskeletal and peripheral nerve systems. More recently, initial studies have applied multiparametric MRI to evaluate quantitatively different aspects of musculoskeletal and peripheral nerve diseases, thus providing not only images but also numbers and clinical data. Besides ¹H and ³¹P magnetic resonance spectroscopy, diffusion-weighted imaging (DWI) and blood oxygenation level-dependent imaging, diffusion tensor imaging (DTI) is a relatively new MRI-based technique relying on principles of DWI, which has traditionally been used mainly for evaluating the central nervous system to track fibre course. In the musculoskeletal and peripheral nerve systems, DTI has been mostly used in experimental settings, with still few indications in clinical practice. In this review, we describe the potential use of DTI to evaluate different musculoskeletal and peripheral nerve conditions, emphasising the translational aspects of this technique from the experimental to the clinical setting.

Preoperative Computed Tomography Myelography Parameters as Predictors of Outcome in Patients With Degenerative Cervical Myelopathy: Results of a Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

To determine the preoperative computed tomography (CT) myelogram imaging parameters in patients diagnosed with degenerative cervical myelopathy (DCM) that correlate with severity of DCM and predict postoperative patients' functional outcome.

METHODS

An electronic database search was performed using Ovid Medline and Embase. CT myelogram studies investigating the correlation between imaging characteristics and DCM severity or postoperative outcomes were included. Two independent reviewers performed citation screening, selection, qualitative assessment, and data extraction using an objective and blinded protocol.

RESULTS

A total of 5 studies (402 patients) were included in this review and investigated the role of preoperative CT myelogram parameters in predicting the functional outcome after surgical treatment of DCM. All studies were retrospective cohort studies. CT myelogram characteristics included the transverse area of the spinal cord at maximum level of compression, spinal canal narrowing, number of blocks, spinal canal diameter, and flattening ratio. There is low evidence suggesting that patients with a preoperative transverse area of the spinal cord >30 mm² at the level of maximum compression have better postoperative recovery and outcome. We found no studies investigating the correlation between preoperative CT myelogram parameters and DCM severity.

CONCLUSIONS

Patients with greater transverse area of spinal cord at the level of maximum compression on the preoperative CT myelogram are more likely to have better neurological outcome after surgery. There is insufficient evidence to suggest that any of the other CT myelogram parameters investigated are predictors of postoperative outcomes in patients with DCM.

Degenerative disease of the lumbar spine

In the last 25 years, scientific research has brought about drastic changes in the concept of low back pain and its management. Most imaging findings, including degenerative changes, reflect anatomic peculiarities or the normal aging process and turn out to be clinically irrelevant; imaging tests have proven useful only when systemic disease is suspected or when surgery is indicated for persistent spinal cord or nerve root compression. The radiologic report should indicate the key points of nerve compression, bypassing inconsequential findings. Many treatments have proven inefficacious, and some have proven counterproductive, but they continue to be prescribed because patients want them and there are financial incentives for doing them. Following the guidelines that have proven effective for clinical management improves clinical outcomes, reduces iatrogenic complications, and decreases unjustified and wasteful healthcare expenditures.

Accuracy of Diffusion Tensor Imaging for Diagnosing Cervical Spondylotic Myelopathy in Patients Showing Spinal Cord Compression

Objective

To assess the performance of diffusion tensor imaging (DTI) for the diagnosis of cervical spondylotic myelopathy (CSM) in patients with deformed spinal cord but otherwise unremarkable conventional magnetic resonance imaging (MRI) findings.

Materials and Methods

A total of 33 patients who underwent MRI of the cervical spine including DTI using two-dimensional single-shot interleaved multi-section inner volume diffusion-weighted echo-planar imaging and whose spinal cords were deformed but showed no signal changes on conventional MRI were the subjects of this study. Mean diffusivity (MD), longitudinal diffusivity (LD), radial diffusivity (RD), and fractional anisotropy (FA) were measured at the most stenotic level. The calculated performance of MD, FA, MD∩FA (considered positive when both the MD and FA results were positive), LD∩FA (considered positive when both the LD and FA results were positive), and RD∩FA (considered positive when both the RD and FA results were positive) in diagnosing CSM were compared with each other based on the estimated cut-off values of MD, LD, RD, and FA from receiver operating characteristic curve analysis with the clinical diagnosis of CSM from medical records as the reference standard.

Results

The MD, LD, and RD cut-off values were 1.079 × 10^-3, 1.719 × 10^-3, and 0.749 × 10^-3 mm²/sec, respectively, and that of FA was 0.475. Sensitivity, specificity, positive predictive value and negative predictive value were: 100 (4/4), 44.8 (13/29), 20 (4/20), and 100 (13/13) for MD; 100 (4/4), 27.6 (8/29), 16 (4/25), and 100 (8/8) for FA; 100 (4/4), 58.6 (17/29), 25 (4/16), and 100 (17/17) for MD∩FA; 100 (4/4), 68.9 (20/29), 30.8 (4/13), and 100 (20/20) for LD∩FA; and 75 (3/4), 68.9 (20/29), 25 (3/12), and 95.2 (20/21) for RD∩FA in percentage value. Diagnostic performance comparisons revealed significant differences only in specificity between FA and MD∩FA (p = 0.003), FA and LD∩FA (p < 0.001), FA and RD∩FA (p < 0.001), MD and LD∩FA (p = 0.024) and MD and RD∩FA (p = 0.024).

Conclusion

Fractional anisotropy combined with MD, RD, or LD is expected to be more useful than FA and MD for diagnosing CSM in patients who show deformed spinal cords without signal changes on MRI.

Prevalence of degenerative changes of the spine on magnetic resonance images and radiographs in patients aged 16-45 years with chronic back pain of short duration in the Spondyloarthritis Caught Early (SPACE) cohort

OBJECTIVES

To determine the prevalence of degenerative changes (DCs) in the spine of young patients with back pain without axial spondyloarthritis (no-axSpA), with possible axSpA (poss-axSpA) and with definite axSpA (axSpA), as shown on MRI and radiographs.

METHODS

Whole-spine MRI and cervical and lumbar radiography were performed in patients ≥16 years of age with chronic back pain (≥3 months, ≤2 years, onset <45 years) and potential axSpA (Spondyloarthritis Caught Early cohort). Patients were classified as no-axSpA, poss-axSpA [not fulfilling the Assessment of Spondyloarthritis International Society (ASAS) axSpA criteria] or axSpA (fulfilling ASAS axSpA criteria). Images (MRI and X-rays) were evaluated on the presence of DCs by two independent readers, blinded to clinical and laboratory information as well as to the results of the other imaging modality. In cases of disagreement, a third reader served as adjudicator. A Chi-square test was used to analyse differences between patient groups according to various selected cut-off points (1-3) of individual DCs.

RESULTS

Of 274 patients (38% male, mean age: 29 years), 25 (9%) were classified as no-axSpA, 134 (48.9%) as poss-axSpA and 115 (42.0%) as axSpA. Two hundred and forty-five (89%) patients had DCs on MRI [21/25 (84%) no-axSpA, 121/134 (90%) poss-axSpA, 103/115 (90%) axSpA, P = 0.792], range 1-29 (median 5.5), and 121 (44%) patients had DCs on radiographs [13/25 (52%) no-axSpA, 62/134 (46%) poss-axSpA, 48/115 (42%) axSpA, P = 0.261], range 1-11 (median 2). Prevalence of DCs was similar between patient groups. DCs were predominantly found in the lumbar spine.

CONCLUSION

Prevalence of DCs was high in this cohort of young patients with short-term chronic back pain, in accordance with the literature. Prevalence of DCs in no-axSpA patients, poss-axSpA patients and axSpA patients was found to be similar.

Magnetic resonance imaging features of Great Danes with and without clinical signs of cervical spondylomyelopathy

OBJECTIVE

To characterize and compare the MRI morphological features of the cervical vertebral column of Great Danes with and without clinical signs of cervical spondylomyelopathy (CSM).

DESIGN

Prospective cohort study.

ANIMALS

30 Great Danes (15 clinically normal and 15 CSM-affected).

PROCEDURES

All dogs underwent MRI of the cervical vertebral column (C2-3 through T1-2). Features evaluated included sites of subarachnoid space compression, spinal cord compression, or both; degree, cause, and direction of compression; MRI signal changes of the spinal cord; articular process (facet) joint characteristics; internal vertebral venous plexus visibility; and presence of extradural synovial cysts as well as presence and degree of intervertebral disk degeneration and foraminal stenosis.

RESULTS

Clinically normal and CSM-affected dogs had 11 and 61 compressive sites, respectively, detected with MRI. All CSM-affected dogs had ≥ 1 site of spinal cord compression. No signal changes were observed in spinal cords of normal dogs, whereas 14 sites of hyperintensity were found in 9 CSM-affected dogs. Foraminal stenosis was present in 11 clinically normal and all CSM-affected dogs. The number of stenotic foraminal sites was significantly greater in the CSM-affected group, and severe stenosis appeared to be more common in this group than in the clinically normal group. Significant differences were identified between clinically normal and CSM-affected dogs with regard to amount of synovial fluid evident, regularity of articular surfaces, degree of articular process joint proliferation, and internal vertebral venous plexus visibility.

CONCLUSIONS AND CLINICAL RELEVANCE

Abnormalities were detected with MRI in several clinically normal Great Danes. Severe spinal cord compression, number of stenotic foraminal sites, and signal changes within the spinal cord distinguished CSM-affected from clinically normal Great Danes.

Basic data underlying decision making in nonatherosclerotic causes of intermittent claudication

Although most cases of vasculogenic intermittent claudication are caused by atherosclerosis, there is an important minority of cases that are due to nonatherosclerotic causes. Because of their rarity and younger population affected, often without traditional atherosclerotic risk factors, there is frequently a significant delay in diagnosis of nonatherosclerotic peripheral arterial diseases by several months to years in some cases. Here, we review the literature on nonatherosclerotic causes of lower extremity claudication, symptoms, management including surgical and endovascular interventions, and outcomes. Conditions included are popliteal artery entrapment syndrome, cystic adventitial disease, pseudoxanthoma elasticum, persistent sciatic artery, fibromuscular disease, giant cell arteritis, iliac endofibrosis, neurogenic claudication, and chronic exertional compartment syndrome.

Characteristics of spondylotic myelopathy on 3D driven-equilibrium fast spin echo and 2D fast spin echo magnetic resonance imaging: a retrospective cross-sectional study

In patients with spinal stenosis, magnetic resonance imaging of the cervical spine can be improved by using 3D driven-equilibrium fast spin echo sequences to provide a high-resolution assessment of osseous and ligamentous structures. However, it is not yet clear whether 3D driven-equilibrium fast spin echo sequences adequately evaluate the spinal cord itself. As a result, they are generally supplemented by additional 2D fast spin echo sequences, adding time to the examination and potential discomfort to the patient. Here we investigate the hypothesis that in patients with spinal stenosis and spondylotic myelopathy, 3D driven-equilibrium fast spin echo sequences can characterize cord lesions equally well as 2D fast spin echo sequences. We performed a retrospective analysis of 30 adult patients with spondylotic myelopathy who had been examined with both 3D driven-equilibrium fast spin echo sequences and 2D fast spin echo sequences at the same scanning session. The two sequences were inspected separately for each patient, and visible cord lesions were manually traced. We found no significant differences between 3D driven-equilibrium fast spin echo and 2D fast spin echo sequences in the mean number, mean area, or mean transverse dimensions of spondylotic cord lesions. Nevertheless, the mean contrast-to-noise ratio of cord lesions was decreased on 3D driven-equilibrium fast spin echo sequences compared to 2D fast spin echo sequences. These findings suggest that 3D driven-equilibrium fast spin echo sequences do not need supplemental 2D fast spin echo sequences for the diagnosis of spondylotic myelopathy, but they may be less well suited for quantitative signal measurements in the spinal cord.

Cytokine concentrations in the cerebrospinal fluid of great danes with cervical spondylomyelopathy

Background

Chronic inflammation is involved in the pathogenesis of human cervical spondylotic myelopathy and could also play a role in cervical spondylomyelopathy (CSM) in dogs.

Hypothesis/Objectives

That cerebrospinal fluid (CSF) cytokine concentrations would differ between clinically normal (control) and CSM‐affected Great Danes (GDs), with affected GDs showing higher levels of inflammatory cytokines, such as interleukin (IL)‐6 and monocyte chemoattractant protein‐1/chemokine ligand 2 (MCP‐1/CCL2).

Animals

Client‐owned GDs: 15 control, 15 CSM‐affected.

Methods

Prospective study. Dogs underwent cervical vertebral column magnetic resonance imaging and collection of CSF from the cerebellomedullary cistern. Cytokine concentrations were measured using a commercially available canine multiplex immunoassay. Cytokine concentrations were compared between groups. Associations with the administration of anti‐inflammatory medications, disease duration and severity, severity of spinal cord (SC) compression, and SC signal changes were investigated in affected GDs.

Results

Affected GDs had significantly lower MCP‐1/CCL2 (mean 138.03 pg/mL, 95% confidence interval [CI] = 114.85–161.20) than control GDs (212.89 pg/mL, 95% CI = 165.68–260.11, P = .028). In affected GDs, MCP‐1/CCL2 concentrations correlated inversely with the severity of SC compression. There were no associations with administration of anti‐inflammatory medications, disease duration, or disease severity. IL‐6 concentrations were significantly higher (2.20 pg/mL, 95% CI = 1.92–2.47, P < .001) in GDs with SC signal changes.

Conclusions and Clinical Importance

Lower MCP‐1/CCL2 in CSM‐affected GDs might compromise clearance of axonal and myelin debris, delay axon regeneration, and affect recovery. Higher IL‐6 in CSM‐affected GDs with SC signal changes suggests more severe inflammation in this group.

Cervical spondylomyelopathy in Great Danes: a magnetic resonance imaging morphometric study

Morphometric investigations comparing normal and affected animals increase our understanding of spinal diseases in dogs. The aim of this study was to generate morphometric data for osseous-associated cervical spondylomyelopathy (CSM) in Great Danes (GDs). Magnetic resonance imaging (MRI) morphometric features of the cervical vertebral column of GDs with and without clinical signs of CSM were characterized and compared. Thirty client-owned GDs were prospectively enrolled, including 15 clinically normal and 15 CSM-affected GDs. All dogs underwent MRI of the cervical to thoracic vertebral column (C2-C3 through T1-T2). Areas of the cranial and caudal articular processes, and the height, width and areas of the vertebral canal and spinal cord were determined. Middle foraminal heights were measured. Intervertebral disc width was measured before and after traction. Intraobserver and interobserver agreement were calculated. CSM-affected GDs had larger areas of the caudal articular processes from C2-C3 through T1-T2. In CSM-affected GDs, the vertebral canal and spinal cord areas were significantly smaller at C5-C6 and C6-C7, the vertebral canal width was significantly narrower at C6-C7 and C7-T1, and the spinal cord width was significantly narrower at C5-C6 and C6-C7. Middle foraminal height was smaller in CSM-affected GDs from C3-C4 through C7-T1. Neutral intervertebral disc widths were smaller in CSM-affected GDs. It was concluded that the cervical vertebral canal dimensions are significantly different between normal and CSM-affected GDs. Absolute vertebral canal stenosis and severe foraminal stenosis involving the cervical vertebrae distinguish CSM-affected from clinically normal GDs. These findings are relevant to the pathogenesis of osseous-associated CSM and should be taken into consideration when performing imaging studies and planning surgery.

Dynamic changes in spinal cord compression by cervical ossification of the posterior longitudinal ligament evaluated by kinematic computed tomography myelography

STUDY DESIGN

A prospective clinical study.

OBJECTIVE

To investigate the dynamic causative factor in the pathogenesis of myelopathy in patients with cervical ossification of the posterior longitudinal ligament (OPLL) using kinematic computed tomography (CT) myelography.

SUMMARY OF BACKGROUND DATA

Kinematic CT myelography is useful for dynamically evaluating the cervical spine with high-resolution images, particularly in bony compressive lesions. However, no studies have evaluated the dynamic factors in patients with OPLL using kinematic CT myelography.

METHODS

From 2008 to 2013, 51 consecutive patients with OPLL who presented with myelopathy were prospectively enrolled in this study. The patients were examined with kinematic (flexion-extension) CT myelography using a multidetector CT scanner. The range of motion at C2-C7 from flexion to extension was measured in the sagittal view. The segmental range of motion, anterior-posterior diameter and cross-sectional area (CSA) of the spinal cord were measured at the level where the spinal cord was most compressed by OPLL.

RESULTS

The neurological condition of the patients evaluated by Japanese Orthopaedic Association scores were 10.8 ± 2.4 points. The mean range of motion at C2-C7 and at the most compressed segment were 23.1 ± 11.7 and 7.0 ± 4.4°, respectively. Both the anterior-posterior diameter and the CSA at the most compressed levels were significantly decreased during neck extension compared with flexion. Interestingly, the anterior-posterior diameter and the CSA were decreased during neck flexion in 13.7% (7/51) of the patients. All 7 of these patients had massive OPLL with an occupying rate 60% or more. The dynamic change rate of CSA (flexion/extension) was significantly smaller in patients with an OPLL occupying rate 60% or more compared with patients with an occupying rate less than 60%.

CONCLUSION

Although spinal cord compression was increased during neck extension in most of the patients, greater levels of compression could be placed on the spinal cord during neck flexion when the patients had OPLL with a high occupying rate.

LEVEL OF EVIDENCE

4.

Compressive myelopathy: magnetic resonance imaging findings simulating idiopathic acute transverse myelopathy

OBJECTIVE

To provide magnetic resonance imaging (MRI) findings of compressive myelopathy simulating idiopathic acute transverse myelopathy (ATM).

MATERIALS AND METHODS

From 19,416 patients who had spinal MRI from 1 September 2004 to 10 July 2011, the patients who met inclusion criteria were enrolled as follows: (1) definable cord compression, (2) long-segmental intramedullary T2-high signal intensity (HSI) extending more than 2 vertebral segments, and (3) no history of trauma, malignancy, or demyelinating disease. The characteristics of T2-HSI and contrast enhancement pattern were analyzed. The patients' clinical information was collected in the process.

RESULTS

Thirteen patients (10 men, 3 women; mean age, 52.8 years; age range, 43-77 years) were included in this study. Twelve patients had cervical cord compression and one had thoracic compression. Common findings of T2-HSI included fusiform shape (100 %) with cord swelling (92.3 %), cord compression in midline location (76.9 %), diffuse distribution occupying more than two-thirds of the cross-sectional dimension of the cord in axial image (84.6 %), and focal and peripheral enhancement (63.6 %). Intravenous corticosteroid was administered to four patients, including two patients following decompressive surgery, and interval decrease in T2-HSI was seen in three patients, but with residual lesions at cord compression level.

CONCLUSIONS

Spinal cord compression can induce long-segmental cord signal change, such as idiopathic ATM.

Cervical spondylotic myelopathy

The differential of cervical spondylotic myelopathy (CSM) is broad and includes multiple conditions that can cause and mimic myelopathy. In adults older than 55 years of age, CSM is the most common cause of myelopathy. This article summarizes the pathophysiology, clinical presentation, differential diagnosis, diagnostic evaluation, and natural history of CSM. Available treatment options and their complications are reviewed.