Comparison of computed tomography myelography and magnetic resonance imaging in the evaluation of cervical spondylotic myelopathy and radiculopathy

Novel MRI signs of ruptured disc in the cervical spine with intraoperative comparisons

OBJECTIVES

To evaluate the diagnostic performance of two novel MRI signs for extruded disc (ED) and uncontained ED (ruptured disc, RD) in the cervical spine using intraoperative findings as reference.

METHODS

This retrospective study included patients who underwent cervical spine MRI and surgery for disc pathology with intraoperative confirmation of RD from September 1, 2016, to January 31, 2021. Two radiologists determined whether the disc was extruded or ruptured with and without the aid of two novel MRI signs suggesting RD (sign 1: blurred margin of the disc; sign 2: mushroom-shaped disc). The diagnostic performance was analyzed using surgical findings as reference. Intra- and interobserver agreements were measured for each MRI sign.

RESULTS

A total of 91 patients totaling 131 discs were enrolled (mean age: 56.02 ± 12.93; range: 26-88; 62 men and 29 women), of whom 62 were surgically confirmed with RD. When the diagnosis was based exclusively on existing ED definitions, ED was diagnosed with 62.9-79.0% sensitivity and 80.2% accuracy, whereas RD was diagnosed with 35.5-45.2% sensitivity and 67.9-71.0% accuracy. However, when the two novel MRI signs were used as an aid in the diagnosis, ED was diagnosed with 95.2-96.8% sensitivity and 84.0-88.5% accuracy, while RD was diagnosed with 95.2-96.8% sensitivity and 84.0-89.3% accuracy. Intra- and interobserver agreement was substantial (k = 00.77-0.86, 0.69-0.79, respectively, p < 0.001).

CONCLUSIONS

The detection of two novel MRI signs on preoperative MRI can lead to a more accurate RD diagnosis.

KEY POINTS

• The diagnostic sensitivity of MRI for cervical ruptured disc is very low (about 35-45 %) using the standardized definition of lumbar disc nomenclature. • Two novel MRI signs can lead to a more accurate diagnosis of the surgically confirmed ruptured disc in the cervical spine. • These two novel MRI signs showed substantial intra-and interobserver reliabilities.

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.

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.

Influence of Myelography and Postmyelographic CT on Therapeutic Decisions in Degenerative Diseases of the Cervical Spine

STUDY DESIGN

A retrospective analysis of clinical records and radiologic imaging by 3 independent reviewers to assess the indication for surgical treatment with and without myelography and postmyelographic computed tomography (MCT).

OBJECTIVE

To evaluate whether myelography and MCT obtained in addition to magnetic resonance imaging (MRI) influence therapeutic decisions in degenerative diseases of the cervical spine.

SUMMARY OF BACKGROUND DATA

MRI has become the standard examination in spinal diseases. The role of myelography and MCT is not clearly defined in the modern diagnostic setup. In many departments, they are used if MRI leaves some diagnostic uncertainty. It has not been examined yet whether additional myelography and MCT change therapeutic strategies.

MATERIALS AND METHODS

Three investigators independently reviewed the anonymized clinical data and image files of 105 patients who had all undergone MRI, myelography, and MCT. They determined their treatment decisions after each of 2 assessment rounds based on the following: (1) MRI and, if available, native CT, and plain radiographs. (2) Additional myelography and MCT. The intraobserver variability was the primary endpoint.

RESULTS

Myelography and MCT had been performed in multilevel disease, recurrent complaints after surgery, or if MRI had not revealed a clear finding. The intraobserver variability was 26.3% and varied markedly between the 3 investigators (17%-41 %). It was the highest in cases of multilevel disease. If noninvasive imaging included native CT and plain radiographs, the intraobserver variability was significantly reduced to 10.3%.

CONCLUSIONS

In unclear cases of degenerative disorders of the cervical spine, particularly multilevel stenosis, myelography and MCT add relevant information for therapeutic decisions in more than a quarter of the patients in comparison with MRI as the sole diagnostic modality, and changes therapeutic strategies. However, a significant part of the information drawn out of myelography and MCT can be obtained by a completion of noninvasive examinations (native CT and radiographs).

Exposure of the examiner to radiation during myelography versus radiculography and root block: A comparative study

BACKGROUND

Exposure to radiation over many years prompts concerns regarding potential health-related effects, particularly the incidence of cataracts and the development of cancer. The purpose of this study was to examine and compare the exposure of the examiner to radiation during myelography versus radiculography and root block.

METHODS

A total of 114 examinations were performed in our institute in the 6 months. Sixty-two examinations were performed during myelography in the first 3 months (MG group), while 52 were performed during radiculography and root block in the last 3 months (RB group). The examiner wore a torso protector, a neck protector, radiation protection gloves, and radiation protection glasses. Optically stimulated luminescence (OSL) dosimeter badges were placed on both the inside and the outside of each protector. The dosimeters were exchanged every month. Radiation doses (mSv) were measured as the integrated radiation quantity every month from the OSL dosimeters. The effective dose and the equivalent doses of hand, skin, and eyes were investigated.

RESULTS

The mean equivalent doses were significantly lower outside the neck, torso, eye protectors, and inside the torso protector in the RB group than in the MG group. Conversely, the mean equivalent dose was significantly lower outside the hand protector in the MG group than in the RB group. The use of a neck protector significantly decreased the effective dose compared to the non-use of a neck protector in the RB group.

CONCLUSIONS

The present study showed the standard radiation exposure to the examiner during myelography, radiculography, and root block. Receiving full protection including a neck protector and protection gloves is an easy and reliable means to reduce radiation exposure.

Evaluation of degenerative disease of the lumbar spine: MR/MR myelography versus conventional myelography/post-myelography CT

BACKGROUND

To compare the use of magnetic resonance (MR)/MR myelography (MRM) with conventional myelography/post-myelography CT (convM) for detailed surgery planning in degenerative lumbar disease.

METHODS

Twenty-six patients with suspected complex lumbar degenerative disease underwent MRM in addition to convM as preoperative workup. Surgery was planned based on convM-as usual at our department. Post hoc, surgical planning was repeated planned again-now based on MRM. Furthermore, the MRM-based planning was performed by six independent neurosurgeons (three groups) of different degrees of specialisation.

RESULTS

In only 31 % of the patients, post hoc MRM-based planning resulted in the same surgical decision as originally performed, whereas in 69 % (n = 18) a different procedure was indicated. In patients with non-concurring convM- and MRM-based surgical plans, a less extended procedure was the result of MRM in six patients (23 %), a more extended one in five (19 %), and a related to side/level of decompression or nucleotomy different plan in six patients (23 %). In one patient (4 %), the MRM-based planning would have led to a completely different surgery compared to convM. Overall interobserver agreement on the MRM-based planning was substantial.

CONCLUSIONS

Detailed planning of operative procedures for complex lumbar degenerative disease is highly dependent on the image modality used.

A blast from the past!: The value of adding single slice magnetic resonance myelography sequence to magnetic resonance imaging of the spine; a flashback to the conventional myelography of the past

Background:

The study was undertaken to determine whether a single slice magnetic resonance (MR) myelogram sequence improves the interpretation and diagnostic yield for magnetic resonance imaging (MRI) of the spine.

Methods:

A total of 100 cases with positive findings were retrospectively reviewed. All patients had initial imaging with sagittal T1-weighted (T1-W) and T2-weighted (T2-W) scans, followed by axial T2-W images. Subsequently, a heavily T2-W single slice MR myelogram sequence was acquired in coronal and sagittal planes. The MR myelogram images were evaluated initially by a radiologist, and, further independently reviewed, by a neurologist, neurosurgeon, and spine surgeon. The utility of the MR myelogram in establishing the diagnosis was graded on a 4-point scale.

Results:

Out of 100 cases, 53% showed degenerative spine or disc disease, 14% space occupying lesions, 13%, congenital lesions, 7% infection, and 7% other conditions. The MR myelogram contributed additional information in 50-74% cases. The intraclass correlation coefficient showed overall good agreement between observers in grading the utility of MR myelogram.

Conclusion:

Single slice MR myelography is noninvasive avoiding the complications associated with lumbar punctures/intrathecal contrast injections, while image acquisition takes only an added 6-8 s. Although MR myelogram has no value as a stand-alone sequence, its inherent advantage is that it completes the overview of the spinal pathology in entirety, and adds vital three-dimensional information in 50-74% of cases.

The study of diagnostic efficacy of nerve conduction study parameters in cervical radiculopathy

BACKGROUND

Cervical Radiculopathy (CR) is a neurologic condition characterised by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. Diagnostic criteria for CR are not well defined, and no universally accepted criteria for its diagnosis have been established. Clinical examination, radiological imaging and electrophysiologic evaluation are the different modalities to diagnose CR. The incidence of Cervical Spondylosis and related conditions is increasing in the present scenario and the use of radiologic examination is time consuming and uneconomical for the common Indian setup. Thus, there is a definite need to establish a cost effective, reliable, and accurate means for establishing the diagnosis of cervical radiculopathy. Electrodiagnostic tests are the closest to fulfill these criteria.

AIM

To evaluate diagnostic utility of various motor and sensory nerve conduction study parameters in cervical radiculopathy.

SETTING AND DESIGN

It was a cross-sectional study conducted on 100 subjects of age > 40 years.

MATERIAL AND METHODS

The consecutive patients clinically diagnosed to have cervical radiculopathy, referred from department of Orthopaedics were prospectively recruited for the motor and sensory nerve conduction study using RMS EMG EP Mark-II. Parameters studied were Compound Muscle Action Potential (CMAP), Distal Motor Latency (DML) and Conduction Velocity (CV) for motor nerves and Sensory Nerve Action Potential (SNAP) and CV for sensory nerves.

STATISTICAL ANALYSIS

Study observations and results were analysed to find the Specificity, Sensitivity, Positive Predictive Value and Negative Predictive Value using SPSS 16.0.

RESULTS

Among various motor nerve conduction parameters CMAP was found to be more sensitive with high positive predicative value. CV was found to have greater specificity and DML had least negative predictive value. Sensory nerve conduction parameters were found to have less sensitivity but higher specificity as compared to motor parameters.

CONCLUSION

Nerve conduction studies are useful supportive diagnostic tool for suspected cervical radiculopathy as they are found to have reliable sensitivity and specificity.

Comparison of noncontrast computed tomography and high-field magnetic resonance imaging in the evaluation of Great Danes with cervical spondylomyelopathy

Computed tomography (CT) provides excellent bony detail, whereas magnetic resonance (MR) imaging is superior in evaluating the neural structures. The purpose of this prospective study was to assess interobserver and intermethod agreement in the evaluation of cervical vertebral column morphology and lesion severity in Great Danes with cervical spondylomyelopathy by use of noncontrast CT and high-field MR imaging. Fifteen client-owned affected Great Danes were enrolled. All dogs underwent noncontrast CT under sedation and MR imaging under general anesthesia of the cervical vertebral column. Three observers independently evaluated the images to determine the main site of spinal cord compression, direction and cause of the compression, articular process joint characteristics, and presence of foraminal stenosis. Overall intermethod agreement, intermethod agreement for each observer, overall interobserver agreement, and interobserver agreement between pairs of observers were calculated by use of kappa (κ) statistics. The highest overall intermethod agreements were obtained for the main site of compression and direction of compression with substantial agreements (κ = 0.65 and 0.62, respectively), whereas the lowest was obtained for right-sided foraminal stenosis (κ = 0.39, fair agreement). For both imaging techniques, the highest and lowest interobserver agreements were recorded for the main site of compression and degree of articular joint proliferation, respectively. While different observers frequently agree on the main site of compression using both imaging techniques, there is considerable variation between modalities and among observers when assessing articular process characteristics and foraminal stenosis. Caution should be exerted when comparing image interpretations from multiple observers.

A comparison of magnetic resonance imaging with electrodiagnostic findings in the evaluation of clinical radiculopathy: a cross-sectional study

PURPOSE

The aim of this study was to evaluate the agreement of magnetic resonance imaging and electrodiagnostic studies by comparing their findings in patients with clinically suspected radiculopathy. The agreements between these two procedures and clinical findings were also examined.

METHODS

In a 2-year cross-sectional study, a total of 114 patients with clinically suspected cervical or lumbosacral radiculopathy were included.

RESULTS

The total agreements between clinical with MRI and EDX findings were 72 and 52%, respectively while their agreements were similar in group definite (89 vs. 82%). The agreement between EDX and MRI was 59.6 in total and 49% with respect to clinical findings.

CONCLUSION

This study further supports that these two methods are complementary in general. It is reasonable to add EDX when there is discrepancy between MRI and clinical findings or when MRI neurologic findings are not visible.

Magnetic resonance imaging evaluation after implantation of a titanium cervical disc prosthesis: a comparison of 1.5 and 3 Tesla magnet strength

Purpose

Cervical disc prostheses induce significant amount of artifact in magnetic resonance imaging which may complicate radiologic follow-up after surgery. The purpose of this study was to investigate as to what extent the artifact, induced by the frequently used Discover^® cervical disc prosthesis, impedes interpretation of the MR images at operated and adjacent levels in 1.5 and 3 Tesla MR.

Methods

Ten subsequent patients were investigated in both 1.5 and 3 Tesla MR with standard image sequences one year following anterior cervical discectomy with arthroplasty.

Outcome measures

Two neuroradiologists evaluated the images by consensus. Emphasis was made on signal changes in medulla at all levels and visualization of root canals at operated and adjacent levels. A “blur artifact ratio” was calculated and defined as the height of the artifact on T1 sagittal images related to the operated level.

Results

The artifacts induced in 1.5 and 3 Tesla MR were of entirely different character and evaluation of the spinal cord at operated level was impossible in both magnets. Artifacts also made the root canals difficult to assess at operated level and more pronounced in the 3 Tesla MR. At the adjacent levels however, the spinal cord and root canals were completely visualized in all patients. The “blur artifact” induced at operated level was also more pronounced in the 3 Tesla MR.

Conclusions

The artifact induced by the Discover^® titanium disc prosthesis in both 1.5 and 3 Tesla MR, makes interpretation of the spinal cord impossible and visualization of the root canals difficult at operated level. Adjusting the MR sequences to produce the least amount of artifact is important.

What is the best way to apply the Spurling test for cervical radiculopathy?

BACKGROUND

A diagnosis of cervical radiculopathy is based largely on clinical examination, including provocative testing. The most common maneuver was described in 1944 by Spurling and Scoville. Since then, several modifications of the original maneuver have been proposed to improve its value in the diagnosis of cervical radiculopathy.

QUESTIONS/PURPOSES

We assessed the ability of six known variations of the Spurling test to reproduce the complaints of patients diagnosed with cervical radiculopathy.

METHODS

We prospectively enrolled 67 patients presenting with cervical radicular-like symptoms and concordant radiographic findings. Each patient underwent six distinct provocative cervical spine maneuvers by two examiners, during which three parameters were recorded: (1) pain intensity (VAS score), (2) paresthesia intensity (0 - no paresthesia, 1 - mild to moderate, and 2 - severe), and (3) characteristic pain distribution (0 - no pain, 1 - neck pain only, 2 - arm pain only, 3 - pain elicited distal to the elbow). The interobserver reliability of the reported VAS score (measured by the intraclass coefficient correlation) ranged from 0.78 to 0.96 and the calculated kappa values of the categorical parameters ranged from 0.58 to 1.0 for paresthesia intensity and from 0.63 to 1.0 for pain distribution. Differences in scores elicited between the two examiners for the 67 patients were resolved by consensus.

RESULTS

A maneuver consisting of extension, lateral bending, and axial compression resulted in the highest VAS score (mean, 7) and was associated with the most distally elicited pain on average (mean, 2.5). The highest paresthesia levels were reported after applying extension, rotation, and axial compression (mean, 1). These maneuvers, however, were the least tolerable, causing discontinuation of the examination on three occasions.

CONCLUSIONS

Whenever cervical radiculopathy is suspected our observations suggest the staged provocative maneuvers that should be included in the physical evaluation are extension and lateral bending first, followed by the addition of axial compression in cases with an inconclusive effect.

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

Spinal stenosis in either the cervical or lumbar spinal segments is one of the most common indications for spine imaging and intervention, particularly among the elderly. This article examines the pathophysiology and imaging of the corresponding clinical syndromes, cervical spondylotic myelopathy or neurogenic intermittent claudication. The specificity fault of spine imaging is readily evident in evaluation of spinal stenosis, as many patients with anatomic cervical or lumbar central canal narrowing are asymptomatic. Imaging also may be insensitive to dynamic lesions. Those imaging features that identify symptomatic patients, or predict response to interventions, are emphasized.

Unexpected neuroimaging abnormalities in patients with apparent C8 radiculopathy: broadening the clinical spectrum

INTRODUCTION

C8-root impingement by C7/T1 lesions on neuroimaging studies is not consistently observed in C8 radiculopathy. We hypothesized that C7 or T1 root lesions (with a pre- or postfixed plexus) or cervical myelopathy might explain some "C8 radiculopathies" without C8 root compression.

METHODS

Retrospective analysis of cervical neuroimaging in 31 consecutive patients with EMG-confirmed C8 radiculopathy.

RESULTS

Five patients (16%) had C8-root compression at C7/T1. Of those without C8-root compression, 5 (16%) had C7-root compression at C6/7, one (3%) had T1-root compression at T1/T2, 7 (23%) had cervical cord compression at or above the C6/7 level, 4 (13%) had intramedullary cervical lesions, and 9 (29%) had mild or nonspecific findings.

CONCLUSIONS

C8 radiculopathy without C8-root compression may be due to C7-root compression in the setting of a "prefixed" brachial plexus, upper cervical cord compression with vascular compromise of the distal cervical spinal cord ("myelopathic hand"), or intramedullary cervical cord lesions.

Computed tomography myelographic findings in dogs with cervical spondylomyelopathy

Computed tomography (CT) myelography is used occasionally in the diagnosis of cervical spondylomyelopathy, but the type of lesion found in large- versus giant-breed dogs using this modality has not been characterized. Our purpose was to report the frequency of compressive lesions in large- and giant-breed dogs with cervical spondylomyelopathy and imaged using CT myelography. Fifty-eight dogs were retrospectively studied, 23 large-breed and 35 giant-breed dogs. Multiple sites of compression were found in 12 large-breed dogs (52.2%) compared to 30 (85.8%) giant-breed dogs. The main site of compression was at C5-6 and C6-7 in both large-breed (91.3%) and giant-breed (72.4%) dogs. The main cause and direction of compression was disc-associated and ventral in 19 (82.6%) of the large-breed dogs while osseous changes were the primary cause of compression in 27 (77.2%) of the giant-breed dogs, with most compressions being lateral (51.4%), followed by dorsolateral (14.2%). Osseous compression was observed at C7-T1 in eight giant-breed dogs (22.8%), and at T1-T2 or T2 only in five dogs (14.3%). Four of 23 large-breed dogs (17.4%), and seven (20%) of 35 giant-breed dogs had spinal cord atrophy. Therefore, giant-breed dogs often have multiple compressions, usually caused by osseous changes causing lateralized compressions. In large-breed dogs most compressions are disc-associated and located ventrally. Considering the number of giant-breed dogs with compressions at C7-T1, T1-2, and T2, it is important to include the cranial thoracic region when imaging dogs suspected of having cervical spondylomyelopathy.

Quadriplegia secondary to cervical spondylotic myelopathy-a rare complication of head and neck surgery

BACKGROUND

Free tissue reconstruction after ablation of head and neck malignancy often requires extensive cervical manipulation, which may exacerbate preexisting cervical spondylosis and result in progression to cervical myelopathy. We present a rare case of postoperative quadriplegia caused by cervical spondylotic myelopathy after head and neck reconstruction.

METHODS AND RESULTS

A 63-year-old man without a history of cervical spondylosis underwent resection of a gingivo-buccal squamous cell carcinoma with immediate reconstruction with free fibula osteocutaneous flap. On postoperative day 4, the patient was found to have quadriplegia. MRI demonstrated severe cervical myelopathy. Decompressive laminectomy was performed. The patient underwent an extensive rehabilitation program but only realized moderate improvement.

CONCLUSION

Cervical spondylotic myelopathy is a rare but disastrous complication of head and neck surgery. We hypothesize that it is potentially avoidable with heightened awareness of this disease entity, preoperative identification of patients at risk, and prophylactic interventions

MRI of the cervical spine with neck extension: is it useful?

OBJECTIVES

Standard MRI of the cervical spine is performed in a different anatomical position to that utilised for traditional contrast myelography. Those well practised in myelography are familiar with the considerable changes in configuration of the bony and soft tissues of the cervical spine that may occur with changes in the degree of neck flexion and extension. We set out to compare the findings in a select group of patients with myeloradiculopathy who had undergone myelography and MRI in both standard and neck-extended positions. These findings were correlated with the clinical status.

METHODS

29 patients underwent myelography with CT (CTM) and MRI in neutral and neck-extended positions. The imaging was assessed for the degree of cord compression and neural foraminal narrowing, quantified using a simple grading scheme suitable for routine clinical practice. The degree of neck extension was assessed using an angular measurement.

RESULTS

For both CTM and MRI, scanning with the neck extended significantly increases the severity of cord compression compared with the standard supine position, to a degree similar to that shown during conventional prone myelography. The degree of perceived cord compression is related to the degree of neck extension achieved. Correlation of standard MRI findings and the clinical level of radiculopathy is poor. This correlation improves when the neck is extended.

CONCLUSIONS

The most appropriate position for routine MRI of the cervical spine in degenerative disease remains unknown, but in selected patients imaging with the neck extended may provide important additional information.

Posterior surgery for cervical myelopathy: indications, techniques, and outcomes

This article details the controversies associated with the different treatment strategies in patients with cervical spondylotic myelopathy. The natural history, incidence, pathophysiology, physical examination, and imaging findings are discussed followed by the indications, techniques, and outcomes of patients treated with posterior cervical decompression via decompressive laminectomy, laminectomy and instrumented fusion, and laminoplasty.

Spinal cord stimulation: the types of neurostimulation devices currently being used, and what radiologists need to know when evaluating their appearance on imaging

Neural stimulation is increasingly used as a treatment for chronic pain. Common indications for spinal cord stimulation include chronic neuropathic and oncological pain, intractable angina, or chronic pain secondary to vascular disease. It is estimated that up to 4 million patients may be candidates for the therapy. Therefore, it is likely that an increasing number of patients will have spinal neurostimulation devices implanted over the coming years. Because radiography and computed tomography are the primary imaging modalities used to evaluate the proper positioning of these devices, radiologists should be familiar with their appearance. The purpose of this article is to discuss the types of neurostimulation devices currently being used and to demonstrate their respective imaging appearances.

Cervical spondylotic myelopathy

BACKGROUND

Cervical spondylosis is part of the aging process and affects most people if they live long enough. Degenerative changes affecting the intervertebral disks, vertebrae, facet joints, and ligamentous structures encroach on the cervical spinal canal and damage the spinal cord, especially in patients with a congenitally small cervical canal. Cervical spondylotic myelopathy (CSM) is the most common cause of myelopathy in adults.

REVIEW SUMMARY

The anatomy, pathophysiology, clinical presentation, differential diagnosis, diagnostic investigation, natural history, and treatment options for CSM are summarized. Patients present with signs and symptoms of cervical spinal cord dysfunction with or without cervical nerve root injury. The condition may or may not be accompanied by pain in the neck and/or upper limb. The differential diagnosis is broad. Imaging, typically with magnetic resonance imaging, is the most useful diagnostic tool. Electrophysiologic testing can help exclude alternative diagnoses. The effectiveness of conservative treatments is unproven. Surgical decompression improves neurologic function in some patients and prevents worsening in others, but is associated with risk.

CONCLUSIONS

Neurologists should be familiar with this very common condition. Patients with mild signs and symptoms of CSM can be monitored. Surgical decompression from an anterior or posterior approach should be considered in patients with progressive and moderate to severe neurologic deficits.

Clinical usefulness of CT-myelogram comparing with the MRI in degenerative cervical spinal disorders: is CTM still useful for primary diagnostic tool?

STUDY DESIGN

A radiographic review of 50 patients (29 radiculopathy and 21 myelopathy) who had undergone the anterior cervical discectomy and fusion was performed by 3 observers retrospectively.

OBJECTIVE

To compare the accuracy between magnetic resonance imaging (MRI) and postmyelographic computed tomography (CTM) in degenerative cervical spine disease by assessing the degree of interobserver and intraobserver agreement.

SUMMARY OF BACKGROUND DATA

The assessment of degenerative cervical spinal disease is still demanding. Now MRI is accepted as a primary diagnostic tool for degenerative cervical spine disease. Compared with MRI, usage of CTM has diminished, but it is usually reserved for the patients for whom MRI results were ambiguous or technically suboptimal.

METHODS

We retrospectively reviewed MRIs and CTMs of 50 patients (29 radiculopathy and 21 myelopathy) who had undergone the anterior cervical discectomy and fusion procedure. Using an assessment scale, 3 observers examined 5 parameters: spinal canal narrowing, foraminal stenosis, bony abnormality, intervertebral disk herniation, and nerve root compression. The degree of severity was graded using a 4-point scale for each item. Intraobserver, interobserver agreement, and the accentuation of each image were analyzed.

RESULTS

Intraclass correlation coefficiency statistical analysis showed moderate intraobserver agreement (Cronbach's alpha=0.63) and interobserver agreement (0.52). There was no significant difference in intraobserver, interobserver agreement between MRI (0.58) and CTM (0.57). Compared between MRI and CTM, disc abnormality and nerve root compression on MRI and foraminal stenosis and bony lesion on CTM showed better agreement.

CONCLUSIONS

CTM was still useful in diagnosis of the foraminal stenosis and bony lesion comparing with MRI but showed limitation in disc abnormality and nerve root compression. So even though CTM may provide valuable additional information in difficult or ambiguous cases, it also requires universal standards and sound experience for constant and objective information.

Comparison of magnetic resonance imaging and computed tomography in predicting facet arthrosis in the cervical spine

STUDY DESIGN

Retrospective review.

OBJECTIVE

To determine the ability of magnetic resonance imaging (MRI) and computed tomography (CT) to predict the presence of cervical facet arthrosis.

SUMMARY OF BACKGROUND DATA

In the Food and Drug Administration Investigational Device Exemption trials of cervical disc arthroplasty (CDA), the presence of facet arthrosis on CT was a contraindication to the insertion of a CDA. Most surgeons routinely obtain an MRI, but not necessarily a CT before performing surgery in the cervical spine. We sought to determine if the MRI alone is adequate to assess for the presence of facet arthrosis.

METHODS

Three experienced spine surgeons retrospectively evaluated CT scans and MRIs of the same patients, obtained within 30 days of each other in a blinded, random fashion. Reviewers graded each of the MRI and CT scan as normal or abnormal on 3 separate occasions and if the facet was abnormal, each reviewer graded the degree of arthrosis. The radiologist's evaluation for each study was compared with our results.

RESULTS

Of 594 facets analyzed, 43.1% were categorized as normal on CT, and of those, MRI concordance was only 63.7% with moderate/substantial intermethod agreement. Furthermore, MRI was concordant only 15.9% of the time in patients with ankylosed facet joints on CT. CT inter-rater reliability showed substantial agreement for diagnoses of both normal and ankylosis and fair agreement for lesser degrees of facet arthrosis. MRI inter-rater reliability showed fair/moderate agreement in normal and ankylosed segments and only slight agreement with lesser degrees of facet arthrosis. CT intrarater reliability showed substantial agreement in normal or ankylosed joints, but only fair agreement for all other categories; MRI showed only fair agreement.

CONCLUSION

The ability of MRI to adequately determine the presence or amount of facet arthrosis is not reliable. Additionally, for abnormal facets, MRI was not reliable in adequately determining the degree of arthrosis. Our data suggest that computed tomography remains necessary in diagnosing facet arthrosis before CDA.

Intra- and inter-observer reliability of MRI examination of intervertebral disc abnormalities in patients with cervical myelopathy

PURPOSE

Intervertebral cervical disc herniation (CDH) is a relatively common disorder that can coexist with degenerative changes to worsen cervicogenic myelopathy. Despite the frequent disc abnormalities found in asymptomatic populations, magnetic resonance imaging (MRI) is considered excellent at detecting cervical spine myelopathy (CSM) associated with disc abnormality. The objective of this study was to investigate the intra- and inter-observer reliability of MRI detection of CSM in subjects who also had co-existing intervertebral disc abnormalities.

MATERIALS AND METHODS

Seven experienced radiologists reviewed twice the MRI of 10 patients with clinically and/or imaging determined myelopathy. MRI assessment was performed individually, with and without operational guidelines. A Fleiss Kappa statistic was used to evaluate the intra- and inter-observer agreement.

RESULTS

The study found high intra-observer percent agreement but relatively low Kappa values on selected variables. Inter-observer reliability was also low and neither observation was improved with operational guidelines. We believe that those low values may be associated with the base rate problem of Kappa.

CONCLUSION

In conclusion, this study demonstrated high intra-observer percent agreement in MR examination for intervertebral disc abnormalities in patients with underlying cervical myelopathy, but differing levels of intra- and inter-observer Kappa agreement among seven radiologists.

Neck and low back pain: neuroimaging

Spine imaging accounts for a major share of expenses related to neck and back pain. Improving image quality translates into better morphologic evaluation of the spine. Unfortunately, the morphologic abnormalities on spine imaging are common and nonspecific, obscuring the relevance to patient symptomatology. Furthermore, distinction between degenerative and age-related changes is not clear. The key is clinical correlation of imaging findings. This article presents a concise and illustrated discussion of spinal neuroimaging related to neck and back pain, with emphasis on degenerative disease.

Magnetic resonance imaging clarity of the Bryan, Prodisc-C, Prestige LP, and PCM cervical arthroplasty devices

STUDY DESIGN

Prospective, randomized, controlled and double-blinded study on imaging of artificial discs.

OBJECTIVE

The purpose of this study is to compare postoperative imaging characteristics of the 4 currently available cervical arthroplasty devices at the level of implantation and at adjacent levels.

SUMMARY OF BACKGROUND DATA

Cervical arthroplasty is being performed increasingly frequently for degenerative disc disease and, in most cases, with frank neural compression. Unlike lumbar arthroplasty, performed mainly for axial back pain, decompression of neural elements may need to be confirmed with postoperative imaging after cervical arthroplasty.

METHODS

Preoperative and postoperative magnetic resonance imaging scans of 20 patients who had undergone cervical arthroplasty were assessed for imaging quality. Five cases each of the Bryan (Medtronic Sofamor Danek, Memphis, TN), Prodisc-C (Synthes Spine, Paoli, PA), Prestige LP (Medtronic Sofamor Danek), and PCM devices (Cervitech, Rockaway, NJ) were analyzed. Six blinded spinal surgeons scored twice sagittal and axial T2-weighted images using the Jarvik 4-point scale. Statistical analysis was performed comparing quality before surgery and after disc implantation at the operated and adjacent levels and between implant types. RESULTS.: Moderate intraobserver and interobserver reliability was noted. Preoperative images of patients in all implant groups had high-quality images at operative and adjacent levels. The Bryan and Prestige LP devices allowed satisfactory visualization of the canal, exit foramina, cord, and adjacent levels after arthroplasty. Visualization was significantly impaired in all PCM and Prodisc-C cases at the operated level in both the spinal canal and neural foramina. At the adjacent levels, image quality was statistically poorer in the PCM and Prodisc-C than those of Prestige LP or Bryan. CONCLUSIONS.: Postoperative visualization of neural structures and adjacent levels after cervical arthroplasty is variable among current available devices. Devices containing nontitanium metals (cobalt-chrome-molybdenum alloys in the PCM and Prodisc-C) prevent accurate postoperative assessment with magnetic resonance imaging at the surgical and adjacent levels. Titanium devices, with or without polyethylene (Bryan disc or Prestige LP), allow for satisfactory monitoring of the adjacent and operated levels. This information is crucial for any surgeon who wishes to assess adequacy of neural decompression and where monitoring of adjacent levels is desired.

A systematic review of the diagnostic accuracy of provocative tests of the neck for diagnosing cervical radiculopathy

Clinical provocative tests of the neck, which position the neck and arm inorder to aggravate or relieve arm symptoms, are commonly used in clinical practice in patients with a suspected cervical radiculopathy. Their diagnostic accuracy, however, has never been examined in a systematic review. A comprehensive search was conducted in order to identify all possible studies fulfilling the inclusion criteria. A study was included if: (1) any provocative test of the neck for diagnosing cervical radiculopathy was identified; (2) any reference standard was used; (3) sensitivity and specificity were reported or could be (re-)calculated; and, (4) the publication was a full report. Two reviewers independently selected studies, and assessed methodological quality. Only six studies met the inclusion criteria, which evaluated five provocative tests. In general, Spurling's test demonstrated low to moderate sensitivity and high specificity, as did traction/neck distraction, and Valsalva's maneuver. The upper limb tension test (ULTT) demonstrated high sensitivity and low specificity, while the shoulder abduction test demonstrated low to moderate sensitivity and moderate to high specificity. Common methodological flaws included lack of an optimal reference standard, disease progression bias, spectrum bias, and review bias. Limitations include few primary studies, substantial heterogeneity, and numerous methodological flaws among the studies; therefore, a meta-analysis was not conducted. This review suggests that, when consistent with the history and other physical findings, a positive Spurling's, traction/neck distraction, and Valsalva's might be indicative of a cervical radiculopathy, while a negative ULTT might be used to rule it out. However, the lack of evidence precludes any firm conclusions regarding their diagnostic value, especially when used in primary care. More high quality studies are necessary in order to resolve this issue.

The value of neurophysiological and imaging studies in predicting outcome in the surgical treatment of cervical radiculopathy

It is not always easy to predict the degree of symptomatic improvement to be expected in a patient undergoing surgery for cervical disc herniation and radiculopathy. Here we investigate whether preoperative electromyography (EMG) can help select those most likely to benefit from intervention. We prospectively evaluated 20 patients whose required operative level was unclear after clinical examination and MRI scan alone. The surgical procedures was anterior cervical interbody fusion with the AcroMed carbon fibre cage. Clinical assessment employed using validated scoring systems (Prolo functional and economic scoring system). Patients underwent MRI preoperatively, and were assessed pre and postoperatively with neurophysiological studies (NPS) including nerve conduction studies and concentric needle EMG. Patients with preoperative evidence of cervical nerve root involvement on EMG (group A, n = 8) had better outcome (P = 0.001) following discectomy and anterior fusion than patients who had no evidence of nerve root damage on EMG (group B, n = 12). Prolo mean score +/- SEM for group A was 7.375 +/- 0.3750 and for group B was 5.583 +/- 0.2876. Thus, NPS are a valuable tool in selecting patients in this subgroup for cervical surgery.

Relationship between Northwick Park neck pain questionnaire and cervical spine MR imaging findings

The study was aimed at determining the association between the self-report of pain and disability by means of Northwick neck pain questionnaire (NPQ) and cervical spine MR imaging findings. A random sample of 251 patients, 132 men and 119 women aged 43+/-13 years, submitted with neck pain were investigated. Patients with previous discitis, surgery, neoplasm or hospitalized for cervical spine trauma were excluded. All patients completed the NPQ and were studied with sagittal gradient-echo T1 and turbo spin-echo T2, axial gradient-echo T2* and heavily T2 weighted MR myelographic weighted images. MR images of the two most affected disc levels were read, offering an MR imaging score from 0 to 30. There was no statistically significant correlation between NPQ and MR imaging scores. From the NPQ items, only difficulty in sleeping and numbness were related to the MR imaging score. Disc extrusion was the only MR finding almost significantly associated with NPQ (P=0.054). Neck injury did not increase NPQ scores. In patients with neck pain, NPQ scores do not correlate with MR imaging findings. NPQ and cervical spine MR imaging show different facets of the multidimensional complex of neck pain.

Subarachnoid hematoma, hydrocephalus, and aseptic meningitis resulting from a high cervical myelogram

Despite its reduced use since the advent of magnetic resonance imaging, the high cervical myelogram remains a common diagnostic test in the evaluation of patients whose symptoms suggest cervical stenosis. We report a case of subarachnoid hematoma, hydrocephalus, and aseptic meningitis after a high cervical myelogram. A 52-year-old woman presented with headache, slurred speech, worsened neck pain and stiffness, and diffuse extremity weakness leading to gait instability beginning several hours after a cervical myelogram. Computed tomography (CT) scan revealed a C1-C2 hematoma below the dura, blood in the fourth and lateral ventricles, and hydrocephalus. An external ventricular drain was placed, and cerebrospinal fluid profile was consistent with aseptic meningitis. A suboccipital craniectomy and C1-C2 laminectomies were performed, followed by a C1-C2 durotomy, which revealed a large subarachnoid blood clot in the region of the cisterna magna extending down to the upper aspect of C2, which was evacuated by incising the arachnoid. In the midline at C1, an active source of intramedullary arterial bleeding on the dorsal surface of the spinal cord was coagulated. Spinal subarachnoid hematoma is a rare complication of high cervical myelogram. The extension of blood into the ventricular system with associated hydrocephalus has never been previously reported after myelography. Thus, severe persistent pain after cervical myelography should be evaluated by CT scans of the brain and cervical spine.

Upper thoracic-spine disc degeneration in patients with cervical pain

OBJECTIVE

To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established.

DESIGN AND PATIENTS

One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6 +/- 14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion.

RESULTS

Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affected level of the upper thoracic spine, with 15 bulge/protrusions and one extrusion. Upper degenerative thoracic disc contour changes presented in older patients than the cervical levels (Student-Newman-Keuls test, P < 0.001). Degenerative disc contour changes at the C7-T1, T1-2, T2-3 and T3-4 levels were significantly correlated ( P = 0.001), but unrelated to any other disc disease, patient's gender or age. Degenerative cervical disc disease was closely related together ( P < 0.001), but not with any thoracic disc.

CONCLUSION

A statistically significant relation was found within the upper thoracic discs, reflecting common pathoanatomical changes. The absence of relation to cervical segments is probably due to differences in their pathomechanisms.

Evaluation of magnetic resonance myelography in the investigation of cervical spondylotic radiculopathy

The objective of this study was to prospectively evaluate the accuracy of MR myelography for the demonstration of foraminal nerve root impingement in cervical spondylotic radiculopathy. 40 patients with cervical spondylotic radiculopathy were imaged with conventional MRI and with MR myelography. The diagnostic accuracy of these imaging strategies for the demonstration of exit foraminal stenosis was calculated relative to a gold standard of the combination of conventional MRI and MR myelography. Conventional MRI had a sensitivity of 88.9%, specificity of 99.1%, and diagnostic accuracy of 94.5% for the demonstration of exit foraminal disease (p<0.001). MR myelography alone had a sensitivity of 84.4%, a specificity of 90.1%, and diagnostic accuracy of 88% (p<0.001). However, the addition of MR myelography increased the diagnostic yield of the MR examination for the detection of foraminal stenotic disease. MR myelography is a useful adjunct to conventional MRI in the investigation of cervical spondylotic radiculopathy.

Imaging of the spine and nerve roots

Advances in imaging have greatly improved the ability to display spine anatomy and pathology. This article describes the imaging findings in degenerative, traumatic, infectious, and neoplastic disease. Anatomic information, however, must be tempered by an understanding of asymptomatic disease and interpreted in the context of the clinical syndrome.

Lumbar spinal stenosis, cauda equina syndrome, and multiple lumbosacral radiculopathies

Narrowing of the vertebral canal, the lateral recess, or the neural foramina causes lumbar spinal stenosis. Stenosis results from degenerative changes that usually are superimposed on a congenitally narrowed spinal canal and can result in significant pain and disability, especially in the elderly. Signs and symptoms are related to the compression of neural and vascular elements from the limited canal space. The article reviews the anatomy and pathophysiology, clinical syndrome, diagnostic workup, and natural history of lumbar spinal stenosis to aid in proper diagnosis and treatment.

Lumbar spinal stenosis assessment with computed tomography, magnetic resonance imaging, and myelography

Degenerative spinal stenosis of the lumbar spine is caused by many factors, some of which include: disc herniation, ligamentum flavum and facet hypertrophy, spondylolisthesis, and compression fracture. Most often the stenosis is caused by a combination of these factors. The imaging modalities in routine use to evaluate these conditions are computed tomography, magnetic resonance imaging and computed tomography-myelogram. They each have their advantages and disadvantages although any one of these modalities can adequately diagnose lumbar stenosis. The overall accuracy rate of computed tomography, magnetic resonance imaging, and computed tomography-myelogram has been reported to be similar and even complimentary. It is recommended that the least invasive modality be performed first. Magnetic resonance imaging should be the first choice because it does not require ionizing radiation or contrast injection. The aim of the current study is to present the common causes of lumbar stenosis. Where appropriate, each case is shown with images from each modality so that their similarities and differences can be highlighted.

Magnetic resonance imaging features of cervical stenotic myelopathy in 21 dogs

The cervical spine of 21 dogs with clinical signs of cervical stenotic myelopathy was evaluated using magnetic resonance (MR) imaging. Spin echo T1, T2 and gradient echo T2 weighted images were obtained with a 1.5 Tesla magnet in 12 dogs and a 1.0 Tesla magnet in 9 dogs. Sagittal or parasagittal T1W and T2W images were helpful in determining the presence of spinal cord compression or degenerative disease of the articular processes. Transverse T1W and T2W images were the most useful for the identification of dorsolateral spinal cord compression secondary to soft tissue and ligament hypertrophy, as well as synovial cysts, associated with the articular processes. The MR imaging findings were consistent with the surgical findings in all 14 dogs that underwent surgery. Magnetic resonance imaging provided a safe, non-invasive method of evaluating the cervical spine in dogs suspected of having cervical stenotic myelopathy. Veterinary