Implications of focal spinal cord lesions following trauma: evaluation with magnetic resonance imaging

Canine Snake-Eye Myelopathy: Clinical, Magnetic Resonance Imaging, and Pathologic Findings in Four Cases

Intramedullary signal change (ISC) is a non-specific finding that is frequently observed on magnetic resonance imaging (MRI) examinations of the canine spinal cord. ISC can represent a variety of primary pathological processes such as neoplasms or myelitides or secondary changes such as edema, cysts, gliosis, or myelomalacia. An unusual phenotype of ISC is the “snake-eye” myelopathy (SEM), which refers to bilaterally symmetric T2 hyperintensities preferentially affecting the ventral horn gray matter on transverse MR images, which resemble a pair of snake's eyes. The pathophysiology of SEM is poorly understood in humans, and this imaging finding may be associated with cervical spondylotic myelopathy, spinal cord ischemia, ossification of the posterior longitudinal ligament, amyotrophic lateral sclerosis, and Hirayama disease. Here we describe four dogs with cervical MRI examinations consistent with an SEM-like phenotype. All dogs initially presented with a central cord syndrome or tetraparesis referable to a C6-T2 neuroanatomic localization, which was attributed to disc-associated spinal cord compression in three cases, while one dog had the SEM-like phenotype with no identifiable etiology. Once the SEM-like phenotype was present on MRI examinations, dogs demonstrated insidious clinical deterioration despite therapeutic interventions. Deterioration was characterized by lower motor neuron weakness and neurogenic muscle atrophy progressing to paralysis in the thoracic limbs, while neurological functions caudal to the level of the SEM-like lesion remained largely preserved for months to years thereafter. Neuropathological features of the SEM-like phenotype include multisegmental cavitations and poliomyelomalacia of laminae VI-IX of the caudal cervical spinal cord, although the lesion evolved into pan-necrosis of gray matter with extension into the adjacent white matter in one case with an 8 years history of progressive disease. Although the pathophysiology of SEM remains unknown, the topographical distribution and appearance of lesions is suggestive of a vascular disorder. As the SEM-like phenotype was uniformly characterized by longitudinally and circumferentially extensive neuronal necrosis, results of this small case series indicate that dogs with clinical signs of central cord syndrome and the SEM-like phenotype involving the cervicothoracic intumescence on MR examinations have a poor prognosis for the preservation or recovery of thoracic limb motor function.

Therapy of an incomplete spinal cord injury by intrathecal injection of EPO and subcutaneous injection of EPO, vitamin C and G-CSF

Spinal cord injury is a rare disease with an incidence about 40 cases per million population in the USA. The most common reasons are traffic accidents, falls, violence and sports. A 53-year-old male patient presented with an incomplete tetraparesis as a result of a spinal cord injury after the accident. It was not possible to treat him with steroids because he was out of the therapeutic time period of 8 hours when he presented to the hospital. The main problem of spinal cord injuries is the secondary injury caused by inflammation and swelling of the spinal cord. To avoid this, the patient was experimentally treated with erythropoietin (EPO) intrathecal and EPO, granulocyte-colony-stimulating factor and vitamin C subcutaneous after his initial spinal cord relief surgery. These drugs might be able to relieve this secondary reaction but were never applied for this indication in human before. This study shows that it could be a promising treatment for spinal cord injuries with potential therapeutic benefits.

Chronic post-traumatic intramedullary lesions in dogs, a translational model

Objectives

Post-traumatic intramedullary myelopathies and cavitations are well described lesions following spinal cord injury (SCI) in humans and have been described in histopathological evaluations in dogs. Human intramedullary myelopathies/cavitations are associated with severe initial SCI and deterioration of clinical signs. Canine intervertebral disc extrusions share similarities with SCI in humans. In this descriptive study, magnetic resonance imaging (MRI) findings in spinal cords of dogs suffering from chronic post-traumatic myelopathies, including cavitations, are elucidated. An additional aim of the study was to compare diagnostic imaging and histopathological findings and identify similarities between human and canine chronic post-traumatic spinal cord lesions.

Methods

Thirty-seven dogs with thoracolumbar SCI and one or more 3Tesla MRI investigations more than 3 weeks after SCI were included. Extent of intramedullary lesions and particularly cavitations were evaluated and measured in sagittal and transverse MRI planes. These data were compared with clinical data.

Results

A total of 91.9% of study patients developed chronic intramedullary lesions, and 86.5% developed intramedullary cavitations. Paraplegia without deep pain perception at initial examination was significantly associated with longer chronic myelopathies/cavitations (P = 0.002/P = 0.008), and with larger maximal cross-sectional area (mCSA) of the lesions (P = 0.041/0.005). In addition, a non-ambulatory status after decompressive surgery was also associated with the development of longer intramedullary lesions/cavitations (P<0.001) and larger lesion mCSA (P<0.001/P = 0.012). All dogs with negative outcome developed myelopathies/cavitations. In the group of 21 dogs with positive outcome, 3 did not develop any myelopathies, and 5 did not develop cavitations.

Conclusions

Development of chronic intramedullary lesions/cavitations are common findings in canine SCI. Extensive chronic intramedullary lesions/cavitations reflect a severe initial SCI and negative clinical outcome. This supports the hypothesis that chronic spinal cord changes following SCI in humans share similarities with canine chronic spinal cord changes after spontaneous intervertebral disc extrusion.

Spinal cord injury after blunt cervical spine trauma: correlation of soft-tissue damage and extension of lesion

BACKGROUND AND PURPOSE

In patients with spinal cord injury after blunt trauma, several studies have observed a correlation between neurologic impairment and radiologic findings. Few studies have been performed to correlate spinal cord injury with ligamentous injury. The purpose of this study was to retrospectively evaluate whether ligamentous injury or disk disruption after spinal cord injury correlates with lesion length.

MATERIALS AND METHODS

We retrospectively reviewed 108 patients diagnosed with traumatic spinal cord injury after cervical trauma between 1990-2011. Plain films, CT, and MR imaging were performed on patients and then reviewed for this study. MR imaging was performed within 96 hours after cervical trauma for all patients. Data regarding ligamentous injury, disk injury, and the extent of the spinal cord injury were collected from an adequate number of MR images. We evaluated anterior longitudinal ligaments, posterior longitudinal ligaments, and the ligamentum flavum. Length of lesion, disk disruption, and ligamentous injury association, as well as the extent of the spinal cord injury were statistically assessed by means of univariate analysis, with the use of nonparametric tests and multivariate analysis along with linear regression.

RESULTS

There were significant differences in lesion length on T2-weighted images for anterior longitudinal ligaments, posterior longitudinal ligaments, and ligamentum flavum in the univariate analysis; however, when this was adjusted by age, level of injury, sex, and disruption of the soft tissue evaluated (disk, anterior longitudinal ligaments, posterior longitudinal ligaments, and ligamentum flavum) in a multivariable analysis, only ligamentum flavum showed a statistically significant association with lesion length. Furthermore, the number of ligaments affected had a positive correlation with the extension of the lesion.

CONCLUSIONS

In cervical spine trauma, a specific pattern of ligamentous injury correlates with the length of the spinal cord lesion in MR imaging studies. Ligamentous injury detected by MR imaging is not a dynamic finding; thus it proved to be useful in predicting neurologic outcome in patients for whom the MR imaging examination was delayed.

[Spinal cord injury and syringomyelia]

Spinal cord injuries often occur in cases of multiple trauma, can occur alone or in combination with concomitant injuries and are mostly associated with high morbidity and mortality. They often result in lifelong impairment and need for medical care. Radiologic diagnostics are crucial in the acute setting as well as in the long-term treatment of spinal cord injuries. Besides an overview of diagnostic and therapeutic management, typical magnetic resonance imaging (MRI) findings in the acute and chronic stages of spinal cord injuries are presented in this article. Post-traumatic syringomyelia can even develop years after the initial injury of the spine or spinal cord. As syringomyelia can also occur in association with tumors, developmental anomalies and also idiopathically, a thorough MRI diagnostic is essential especially in any case of newly diagnosed syringomyelia.

Diagnostic and prognostic role of MRI in spinal trauma, its comparison and correlation with clinical profile and neurological outcome, according to ASIA impairment scale

Aims and objectives:

To evaluate the role of magnetic resonance imaging (MRI) as a non-invasive diagnostic tool in patients with acute and chronic spinal trauma and to compare and correlate the MRI findings with those of patients’ clinical profile and neurological outcome according to ASIA impairment scale to assess prognostic and clinical value of MRI.

Materials and Methods:

Sixty two patients of spinal trauma formed the study group in a prospective fashion. The patients undergoing MR imaging and magnetic resonance images were analyzed and correlated with findings on neurological examination according to American Spinal Injury Association (ASIA) impairment scale (AIS) at the time of MRI examination and subsequently at sub-acute interval to assess neurological outcome.

Statistical Analysis:

Sample profile was described in terms of 95% confidence limit and proportion. To describe strength of association between extent of spinal cord injury and outcome, odd's ratio, bivariate and multi variant analysis, was used. Pearson's chi square (χ) ² statistics was applied to test the association between two categorical variables. Data were analyzed using statistical software package, STATA 9.2 and the difference was considered to be significant if ‘P’ value was <0.05.

Observation and Results:

The cord edema without hemorrhage was the most common MR finding (41.5%). The others were sizable focus of hemorrhage within the cord (33%), epidural hematoma (5.0%), and normal cord (26%). Majority of MR findings correlated well with clinical profile of the patient according to ASIA impairment scale. This study demonstrated that patients with presence of sizable focus of haemorrhage had larger cord edema and more severe grade of initial ASIA impairment scale( AIS) with poor recovery at follow up (P=0.032).Improvement in upper extremity was more than lower extremity. Severe cord compression was also associated with poor neurological outcome; however it was not statistically significant (P=0.149).

Conclusions:

With this study the authors concluded that various MRI findings in acute spinal cord injury correlated well with the initial clinical findings and on follow-up according to ASIA impairment scale. MRI is useful for initial diagnosis of acute spinal cord injury and its prognostication for predicting neurological recovery.

Lesion growth and degeneration patterns measured using diffusion tensor 9.4-T magnetic resonance imaging in rat spinal cord injury

OBJECT

Using diffusion tensor MR imaging, the authors conducted a study to explore lesion growth and degeneration patterns, from the acute through chronic stages of spinal cord injury (SCI), in an experimental animal model.

METHODS

In vivo and ex vivo diffusion tensor imaging was performed using a 9.4-T MR imaging system in rats allowed to recover from traumatic contusion SCI from 2 weeks through 25 weeks postinjury, mimicking progression of human SCI from the acute through chronic stages.

RESULTS

Results showed significant growth of the traumatic lesion up to 15 weeks postinjury, where both the size and mean diffusivity (MD) reached a maximum that was maintained through the remainder of recovery. Mean diffusivity was sensitive to overall spinal cord integrity, whereas fractional anisotropy showed specificity to sites of cavity formation. The use of an MD contour map for in vivo data and a 3D surface map for ex vivo data, showing MD as a function of rostral-caudal distance and recovery time, allowed documentation of rostral and caudal spreading of the lesion.

CONCLUSIONS

Results from this study demonstrate changes in both lesion morphology and diffusivity beyond previously reported time points and provide a unique perspective on the process of cavity formation and degeneration following traumatic SCI. Additionally, results suggest that MD more accurately defines regions of histological damage than do regions of T2 signal hyperintensity. This could have significant clinical implications in the detection and potential treatment of posttraumatic syringes in SCI.

Brown-Sequard syndrome after blunt cervical spine trauma: clinical and radiological correlations

The objective of this study was to describe clinical and radiological features of a series of patients presenting with Brown-Sequard syndrome after blunt spinal trauma and to determine whether a correlation exists between cervical plain films, CT, MRI and the clinical presentation and neurological outcome. A retrospective review was done of the medical records and analysis of clinical and radiological features of patients diagnosed of BSS after blunt cervical spine trauma and admitted to our hospital between 1995 and 2005. Ten patients were collected for study, three with upper- and seven with lower-cervical spine fracture. ASIA impairment scale and motor score were determined on admission and at last follow-up (6 months-9 years, mean 30 months). Patients with lower cervical spine fracture presented with laminar fracture ipsilateral to the side of cord injury in five out of six cases. T2-weighted hyperintensity was present in seven patients showing a close correlation with neurological deficit in terms of side and level but not with the severity of motor deficit. Patients with Brown-Sequard syndrome secondary to blunt cervical spine injury commonly presented T2-weighted hyperintensity in the clinically affected hemicord. A close correlation was observed between these signal changes in the MR studies and the neurologic level. Effacement of the anterior cervical subarachnoid space was present in all patients, standing as a highly sensitive but very nonspecific finding. In the present study, craniocaudal extent of T2-weighted hyperintensity of the cord failed to demonstrate a positive correlation with neurological impairment.

Neurologic recovery according to early magnetic resonance imaging findings in traumatic cervical spinal cord injuries

The aim of this study was to determine the usefulness of early magnetic resonance imaging findings in predicting neurologic recovery at or below the injured level in traumatic cervical spinal cord injuries. Thirty patients with traumatic cervical spinal cord injuries were included. All of the patients received a magnetic resonance imaging and a neurologic examination in the emergency room, within 7 days of injury and at 6 months following the injury. To quantify neurologic recovery below the injured level, we modified clinical scales, particularly the motor ratio and the sensory ratio. We used the neurologic level to quantify recovery around the injured level. We assessed neurologic recovery according to MRI patterns and lesion extents. The pure hemorrhagic MRI pattern was not observed. In edematous and mixed types, the improvement of neurologic levels was not significantly different. The motor ratio and sensory ratio improved significantly more in edematous type patients than in mixed type patients. Based on MRI lesion extent, the improvement of neurologic levels was not significantly different, and motor ratio and sensory ratio improved significantly more in those with one or two segments involved than in those with more than two segments involved. In conclusion, early MRI pattern and lesion extent after traumatic cervical spinal cord injury may provide important information to help predict neurologic recovery, especially below the injured level.

Pictorial review: MRI of chronic spinal cord injury

Patients who have suffered a spinal cord injury and who demonstrate new or changing clinical features such as increasing myelopathy, ascending neurological level, pain or increasing muscle spasms may have developed a late complication such as post-traumatic syrinx. MRI is the investigation of choice for assessment of chronic spinal cord injury. The aim of this pictorial review is to illustrate the various late appearances of the injured spinal cord.

Recurrent central cord syndrome at the level of a solid cervical vertebral fusion

STUDY DESIGN

A case of a solid cervical vertebral fusion that failed to protect against recurrent central cord syndrome at the same spinal level is described.

OBJECTIVES

To alert clinicians to the potential for incomplete spinal cord lesions at the same level as cervical vertebral fusions.

SUMMARY OF BACKGROUND DATA

The clinical symptomatology of central cord syndrome is discussed and the advantages of T2-weighted magnetic resonance imaging in such cases is considered. No prior reports of central cord syndrome occurring directly posterior to a solidly fused disc segment were found in the literature.

METHODS

The clinical and T2-weighted magnetic resonance imaging features associated with central cord syndrome are presented. The traumatized region developed immediately posterior to the site of an anterior cervical diskectomy and uncovertebral osteophytectomy between the fourth and fifth cervical vertebrae with bone grafting that had been performed more than 3 years earlier.

RESULTS

Symptoms of the central cord syndrome resolved over the course of 4 months with no other intervention other than the use of a Philadelphia cervical collar. Five years later, the patient remained symptom free.

CONCLUSION

This case illustrates that clinicians must be aware of the potential occurrence of central cord syndrome in patients with solidly fused cervical segments, and that cervical fusion does not necessarily protect against future incomplete spinal cord injury, such as central cord syndrome, at the level of the fusion.

Magnetic resonance imaging of sports injuries of the spine

Spinal injuries are relatively frequent events in professional athletes. Greater popularity of recreational athletic activities has increased the occurrence of sports-related spinal injuries in the general population. The demand of high-intensity sports places a constant load on the vertebral column. Several studies have demonstrated higher prevalence of spinal abnormalities in athletes than nonathletes. Direct correlation of the number and extent of injuries with the length in years of sports activity has been established. Diagnostic imaging, particularly magnetic resonance imaging (MRI), plays a crucial role in evaluating and detecting sports-related spinal injuries. Subtle bone marrow, soft-tissue, and spinal cord abnormalities, which may not be apparent on other imaging modalities, can be readily detected on MRI. Early detection often leads to prompt accurate diagnosis and expeditious management, in many cases avoiding unnecessary procedures. This article reviews the technical aspects of MRI for evaluation of the spine and the role of MRI in the assessment of sports-related spinal injuries.

Electrodiagnosis in spinal cord injured persons with new weakness or sensory loss: central and peripheral etiologies

OBJECTIVE

To assess the prevalence and causes of late neurologic decline of persons with spinal cord injury (SCI).

DESIGN

Retrospective review of persons with SCI over a 9-year period. Those with complaints of new weakness or sensory loss were grouped into three categories based on clinical examination, electrodiagnosis, and imaging: (1) central pathology (ie, brain, spinal cord, or nerve root); (2) peripheral pathology (plexus or peripheral nerve); or (3) no identifiable etiology. The specific diagnoses of late neurologic decline were identified.

SETTING

Regional Veterans Affairs Spinal Cord Injury Service.

PATIENTS

Five hundred two inpatient and outpatient adults with SCI.

RESULTS

Nineteen percent of the study population complained of new weakness and/or sensory loss. Neurologic abnormalities were noted in 13.5%, 7.2% with central and 6.4% with peripheral causes. The most common pathologies were posttraumatic syringomyelia (2.4%) and cervical (1.6%) and lumbosacral (1.2%) myelopathy/radiculopathy. A specific etiology was not determined in 6 cases (1.6%). Peripheral involvement was mostly from ulnar nerve entrapment (3.4%) and carpal tunnel syndrome (3.0%).

CONCLUSIONS

Late-onset neurologic decline is common after SCI and can result from central or peripheral pathology. Regular neurologic monitoring of SCI patients is recommended, since many with neurologic decline respond favorably if diagnosed and treated early.

Metallic artifacts in magnetic resonance imaging of patients with spinal fusion. A comparison of implant materials and imaging sequences

STUDY DESIGN

Devices for spinal fusion were compared with respect to their influence on magnetic resonance images. In addition, different magnetic resonance pulse sequences were evaluated to elicit their susceptibility to imaging artifacts.

OBJECTIVES

To determine the implants with the least imaging artifacts as a recommendation for the spine surgeon and to assess the best imaging strategy for the radiologist.

SUMMARY OF BACKGROUND DATA

For patients who have had surgical spinal fusion with instrumentation, magnetic resonance imaging is the most favorable diagnostic method. Unfortunately, metallic implants lead to severe degradation of image quality. These artifacts depend on the material of the implant and on the choice of the pulse sequence.

METHODS

The fusion devices were mounted on a simple plastic phantom in various combinations and were imaged on 1.5-T magnetic resonance units. Frequently used types of plates and screws made of titanium or steel in various alloys were examined on the phantom with routinely used pulse sequences. The results of these examinations were compared with those in patient studies involving the same implants as well as the same pulse sequences.

RESULTS

The least imaging artifacts were caused by titanium implants, especially when using shorter screws, wider screw placement, and thinner titanium plates. Nevertheless, there were distinct image distortions that could lead to erroneous image interpretation. The best images were acquired by spin echo (T1), turbo spin echo (T1, T2), and half Fourier single shot turbo spin echo (HASTE) sequences. Sequences containing any gradient echo components (gradient echo or turbo gradient and spin echo sequence or frequency-selective fat saturation techniques) resulted in the highest amount of image degradation.

CONCLUSION

By choosing appropriate spinal fusion devices as well as pulse sequences, postoperative magnetic resonance imaging examinations can give acceptable results, in spite of the presence of metallic implants.

Spinal injuries in the pediatric age group: a review of 82 cases of spinal cord and vertebral column injuries

A review of 82 children with spinal cord and/or vertebral column injury treated in our department between 1968 and 1993 showed that 67% of the patients were boys and the average age was 11.4 years. The cause, vertebral level, and type of injury, and the severity of neurological injury varied with the age of the patient. The cause of pediatric injuries differed from that of adult injuries in that falls were the most common causative factor (56%) followed by vehicular accidents (23%). The most frequent level of spinal injury was in the cervical region (57%, 47 patients) followed by the lumbar region (16.5%, 13 patients). In our series, 18% of the patients had complete injury and the overall mortality rate was 3.6%. Eleven children (13%) had spinal cord injury without radiographic abnormality (SCIWORA), whereas 39 (47%) had evidence of neurological injury. Although the spinal injury patterns differed between children and adolescents, the outcome was found to be predominantly affected by the type of neurological injury (P < 0.05). Children with complete myelopathy uniformly remained with severe neurological dysfunction; children with incomplete myelopathy recovered nearly normal neurological function. Finally, the authors conclude that most spinal injuries can be successfully managed with nonoperative therapy. The literature is reviewed as to the treatment and outcome of pediatric spinal injuries.