Magnetic resonance imaging in acute spinal injury

Role of magnetic resonance imaging features in diagnosing and localization of disc rupture related to cervical spinal cord injury without radiographic abnormalities

STUDY DESIGN

A retrospective study.

OBJECTIVE

Traumatic cervical spinal cord injury (TSCI) is often associated with disc rupture. It was reported that high signal of disc and anterior longitudinal ligament (ALL) rupture on magnetic resonance imaging (MRI) were the typical signs of ruptured disc. However, for TSCI with no fracture or dislocation, there is still difficult to diagnose disc rupture. The purpose of this study was to investigate the diagnostic efficiency and localization method of different MRI features for cervical disc rupture in patient with TSCI but no any signs of fracture or dislocation.

SETTING

Affiliated hospital of University in Nanchang, China.

METHODS

Patients who had TSCI and underwent anterior cervical surgery between June 2016 and December 2021 in our hospital were included. All patients received X-ray, CT scan, and MRI examinations before surgery. MRI findings such as prevertebral hematoma, high-signal SCI, high-signal posterior ligamentous complex (PLC), were recorded. The correlation between preoperative MRI features and intraoperative findings was analyzed. Also, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of these MRI features in diagnosing the disc rupture were calculated.

RESULTS

A total of 140 consecutive patients, 120 males and 20 females with an average age of 53 years were included in this study. Of these patients, 98 (134 cervical discs) were intraoperatively confirmed with cervical disc rupture, but 59.1% (58 patients) of them had no definite evidence of an injured disc on preoperative MRI (high-signal disc or ALL rupture signal). For these patients, the high-signal PLC on preoperative MRI had the highest diagnostic rate for disc rupture based on intraoperative findings, with a sensitivity of 97%, specificity of 72%, PPV of 84% and NPV of 93%. Combined high-signal SCI with high-signal PLC had higher specificity (97%) and PPV (98%), and a lower FPR (3%) and FNR (9%) for the diagnosis of disc rupture. And combination of three MRI features (prevertebral hematoma, high-signal SCI and PLC) had the highest accuracy in diagnosing traumatic disc rupture. For the localization of the ruptured disc, the level of the high-signal SCI had the highest consistency with the segment of the ruptured disc.

CONCLUSION

MRI features, such as prevertebral hematoma, high-signal SCI and PLC, demonstrated high sensitivities for diagnosing cervical disc rupture. High-signal SCI on preoperative MRI could be used to locate the segment of ruptured disc.

Imaging of trauma of the spine

The goal of imaging in spine trauma is to gauge the extent of bony, vascular, and neurologic compromise. Neurologic and mechanical stability are key pieces of information that must be efficiently communicated to the referring clinician. From immobilization and steroid therapy, to vascular repair and emergent surgical intervention, clinical outcomes of spine-injured patients depend on timely and well-chosen imaging studies. Multidetector computed tomography (CT) has essentially replaced radiography in clearance of the spine and is the gold standard in evaluation of the bony spinal column. Magnetic resonance imaging (MRI) is typically reserved for patients with neurologic deficits or for obtunded/impaired patients in whom the neurologic exam is not reliable, even in the absence of osseous injury on CT. MRI is the only available imaging modality that is able to clearly depict the internal architecture of the spinal cord, and, as such, has a central role in depicting parenchymal changes resulting from injury. Intramedullary edema and hemorrhage have been shown to correlate with the degree of neurologic deficit and prognosis. Moreover, advanced MRI techniques, such as diffusion and diffusion tensor imaging, have shifted the focus to determining structural and functional integrity of neural structures. Here, we review the role of imaging in spine trauma, as well as the key radiologic features of injury to the spinal column and spinal cord.

Intraaxial Spinal Cord Hemorrhage Secondary to Atlantoaxial Subluxation in a Dog

A 1-year-old, 3.5-kg, spayed female, toy poodle was presented for acute-onset tetraplegia and neck pain. Neuroanatomical diagnosis was consistent with a first through fifth cervical (C1 through C5) spinal cord lesion. Radiographs of the cervical vertebral column revealed atlantoaxial (AA) subluxation. Magnetic resonance imaging revealed abnormalities consistent with intraaxial spinal cord hemorrhage at the level of the AA articulation. The dog was treated with external coaptation. After 8 days, the dog regained voluntary motor function in all four limbs. Surgical stabilization was pursued. Postoperatively, the dog regained the ability to ambulate. This report details the imaging findings and management of a dog with intraaxial spinal cord hemorrhage secondary to AA subluxation.

MRI of cervical spine injuries complicating ankylosing spondylitis

OBJECTIVE

The objective was to study characteristic MRI findings in cervical spine fractures complicating ankylosing spondylitis (AS). Technical issues related to MRI are also addressed.

MATERIALS AND METHODS

A review of 6,774 consecutive cervical spine multidetector CT (MDCT) scans obtained during 6.2 years revealed 33 ankylosed spines studied for suspected acute cervical spine injury complicating AS. Of these, 20 patients also underwent MRI.

RESULTS

On MRI, of these 20 patients, 19 had a total of 29 cervical and upper thoracic spine fractures. Of 20 transverse fractures traversing both anterior and posterior columns, 7 were transdiskal and exhibited less bone marrow edema than did those traversing vertebral bodies. One Jefferson's, 1 atlas posterior arch (Jefferson's on MDCT), 2 odontoid process, and 5 non-contiguous spinous process fractures were detectable. MRI showed 2 fractures that were undetected by MDCT, and conversely, MDCT detected 6 fractures not seen on MRI; 16 patients had spinal cord findings ranging from impingement and contusion to complete transection.

CONCLUSION

Magnetic resonance imaging can visualize unstable fractures of the cervical and upper thoracic spine. Paravertebral hemorrhages and any ligamentous injuries should alert radiologists to seek transverse fractures. Multiple fractures are common and often complicated by spinal cord injuries. Diagnostic images can be obtained with a flexible multipurpose coil if the use of standard spine array coil is impossible due to a rigid collar or excessive kyphosis.

Posterior longitudinal ligament status in cervical spine bilateral facet dislocations

OBJECTIVE

It is generally accepted that cervical spine bilateral facet dislocation results in complete disruption of the posterior longitudinal ligament. The goal of this study was to evaluate the integrity of numerous spine-stabilizing structures by MRI, and to determine if any associations between injury patterns exist with respect to the posterior longitudinal ligament status.

DESIGN

Retrospective case series.

PATIENTS

A retrospective review was performed of 30 cervical spine injury subjects with bilateral facet dislocation. Assessment of 1.5T MRI images was carried out for: intervertebral disc disruption, facet fracture, and ligamentous disruption. Statistical analyses were performed to evaluate for associations between various injury patterns and posterior longitudinal ligament status.

RESULTS

The frequency of MRI abnormalities was: anterior longitudinal ligament disruption (26.7%), disc herniation or disruption (90%), posterior longitudinal ligament disruption (40%), facet fracture (63.3%) and disruption of the posterior column ligament complex (97%). There were no significant associations between injury to the posterior longitudinal ligament and other structures. Compared to surgical reports, MRI was accurate for determining the status for 24 of 26 ligaments (three of three anterior longitudinal ligament, seven of nine posterior longitudinal ligament, and 14 of 14 posterior column ligament complex) but generated false negatives in two instances (in both MRI showed an intact posterior longitudinal ligament that was torn at surgery).

CONCLUSIONS

In contradistinction to the existing concept, the posterior longitudinal ligament can remain intact in a substantial proportion of hyperflexion injuries that produce bilateral cervical facet dislocation. Posterior longitudinal ligament integrity is not associated with any other injury pattern related to the anterior longitudinal ligament, intervertebral disc or facet fracture.

[Ankylosing spondylitis. Therapy and complications of 34 spine fractures]

BACKGROUND

Spine fractures in ankylosing spondylitis (AS) are extremely unstable and associated with a high complication rate. The aim of this retrospective study was to evaluate the therapy and complications of these fractures in AS for a better understanding and management.

PATIENTS AND METHODS

A total of 32 patients with 34 traumatic spine fractures were treated from 1981 to 2002. Cause of trauma, fracture site, and neurological examination were assessed. Analyses of the management of the treatment and complications were performed.

RESULTS

Banal traumas resulted mostly in spinal fractures at the C 5/6 and C 6/7 level. Two patients were treated conservatively, while the others were stabilized operatively. Before therapy was undertaken, six patients suffered from a cervical radiculopathy, ten patients had an incomplete and two a complete paraplegia. After therapy, neurological status improved in eight patients, but one had a deterioration of neurological symptoms.

CONCLUSIONS

Dorsal or combined dorsoventral stabilization of these fractures is necessary for better mobilization of these patients and to avoid further complications.

Acute intervertebral disc extrusion in a cat: clinical and MRI findings

A 5 year old, neutered male, domestic shorthaired cat had acute left hemiparesis and Horner's syndrome. Magnetic resonance imaging (MRI) revealed a loss of the normal signal from the nucleus pulposus of the intervertebral disc at C3/4, narrowing of the ventral subarachnoid space and slight dorsal displacement of the spinal cord and a focal hyperintense lesion affecting the left side of the spinal cord at the same level. The presumptive diagnosis was focal spinal cord oedema associated with intervertebral disc extrusion. A traumatic aetiology was suspected. The cat was treated conservatively and improved gradually over a period of 6 months.

Magnetic resonance imaging analysis of soft tissue disruption after flexion-distraction injuries of the subaxial cervical spine

STUDY DESIGN

A retrospective study was performed with the use of magnetic resonance imaging to evaluate the type and degree of soft tissue disruption associated with flexion-distraction injuries of the subaxial spine.

OBJECTIVE

To determine what soft tissue structures are injured in flexion-distraction injuries of the subaxial spine.

SUMMARY OF BACKGROUND DATA

Prior published reports of unilateral and bilateral cervical facet dislocations have described the analyzed mechanisms and biomechanics of this injury subtype. No retrospective magnetic resonance imaging analysis of associated soft tissue disruption has been documented.

METHODS

Magnetic resonance imaging evaluations of the cervical spine were obtained for all patients with a flexion-distraction injury, Stages 2 (unilateral facet dislocation) and 3 (bilateral facet dislocation), between September 1994 and May 1998. Two neuroradiologists, blinded to both clinical and radiographic findings, graded all the soft tissue structures for evidence of attenuation or disruption. The soft tissue structures were graded on a scale of 1 (intact), 2 (indeterminate), or 3 (disrupted).

RESULTS

For this study, 48 patients satisfied the inclusion criteria: 25 with unilateral facet dislocation and 23 with bilateral facet dislocation. Disruption to the posterior musculature, interspinous ligament, supraspinous ligament, facet capsule, ligamentum flavum, and posterior and anterior longitudinal ligaments was found in a statistically significant number of patients with bilateral facet dislocation. For most of these structures, disruption was found to be statistically significant in patients with a unilateral facet dislocation, except for the posterior longitudinal ligament, in which significance was not consistently demonstrated using 95% confidence intervals in the binomial testing. In a comparison between unilateral and bilateral facet dislocations using a two-sided Fisher's exact test, it was found that disruption to the anterior and posterior longitudinal ligaments and the left facet capsule were statistically significant, with all three more prominent in bilateral facet dislocation. A multivariate analysis between unilateral and bilateral facet dislocations showed that disruption to the anterior longitudinal ligament was associated significantly with a bilateral facet dislocation. Disc disruption was found to be associated significantly with both injury types, but was more common in bilateral facet dislocation, although this difference in intergroup comparisons was not statistically significant.

CONCLUSIONS

Unilateral and bilateral facet dislocations of the subaxial spine are associated with damage to numerous soft tissue structures that provide stability to the lower cervical spine. Damage to the posterior longitudinal ligament did not occur consistently in unilateral facet dislocations. Bilateral facet dislocations were associated significantly with disruption to the posterior and anterior longitudinal ligaments and left facet capsule, as compared with unilateral facet dislocations. Magnetic resonance imaging allows visualization of these disruptions.

Evaluation of unstable cervical spine injury: a 6-year experience

BACKGROUND

The diagnosis of the unstable cervical spine, and its subsequent management can be difficult and a missed cervical spine injury can obviously have devastating consequences.

METHODS

This study describes a 6-year experience with these injuries and presents an algorithm for their evaluation. The case records of 100 consecutive patients who underwent an operative procedure for an unstable cervical spine injury were reviewed.

RESULTS

The population and injury characteristics were similar to that of previous studies. The process of evaluation of the spine was robust but failed to identify two unstable ligamentous injuries not detected on initial radiologic examination. Ten patients whose injuries were missed at other hospitals were identified by using this system.

CONCLUSION

A systematic, well-structured approach to the potentially injured cervical spine allows safe and effective diagnosis and management of these patients. Failure to adhere to basic principles will result in missed unstable cervical spine injuries.

MR imaging of suspected acute spinal instability

Twenty-two patients with suspected acute vertebral instability were imaged within 48 h of injury using a 0.5 Tesla magnet. In all patients plain radiographs, T1 weighted gradient echo (GE) and STIR sequences were performed. Two radiologists blindly evaluated the magnetic resonance imaging (MRI) scans defining injuries with bony or soft tissue disruption of both columns as unstable. Indirect signs of instability such as soft tissue haemorrhage were recorded and correlated where possible with operative findings. Sixteen patients were radiologically unstable on MRI, five more than on plain films alone. Instability was confirmed operatively in 10 patients. The six other patients with unstable injuries were treated conservatively. Two of these patients had evidence of increased deformity before fracture union. The radiologically stable patients were treated as such and at 6-month review showed no evidence of progressive instability. The presence of soft tissue haemorrhage in the interspinous gap was not associated with ligament rupture unless actual discontinuity was demonstrated at that level. We conclude that using MRI acutely, most unstable spinal injuries can be rapidly and accurately evaluated without the need for further imaging.