Year : 2004 | Volume
: 14 | Issue : 1 | Page : 71--80
Prospective evaluation of cervical spine injuries by MRI and assessing role of MR findings in predicting prognosis
S Khandelwal, GL Sharma, UD Saxena, P Sakhi, S Gopal, P Saxena
Dept. of Radiodiagnosis, G.R. Medical College, Gwalior, India
Dept. of Radiodiagnosis, G.R. Medical College, Gwalior
|How to cite this article:|
Khandelwal S, Sharma G L, Saxena U D, Sakhi P, Gopal S, Saxena P. Prospective evaluation of cervical spine injuries by MRI and assessing role of MR findings in predicting prognosis.Indian J Radiol Imaging 2004;14:71-80
|How to cite this URL:|
Khandelwal S, Sharma G L, Saxena U D, Sakhi P, Gopal S, Saxena P. Prospective evaluation of cervical spine injuries by MRI and assessing role of MR findings in predicting prognosis. Indian J Radiol Imaging [serial online] 2004 [cited 2019 Nov 16 ];14:71-80
Available from: http://www.ijri.org/text.asp?2004/14/1/71/28561
Purpose of Study
To determine the role of MRI in prospective detection of acute cervical spine injury.To compare the findings of MR Imaging with those of a comprehensive Conventional Radiographic assessment.To assess factors which affect outcome in patients with Cervical Spinal Cord Injury.To assess prognosis of Cervical Spinal Cord Injury with bony injury and without bony injury (SCIWORA) on the basis of MR findings.
Materials and Methods
This study, carried out in the Department of Radiodiagnosis, G. R. Medical College & Associated J.A. Group of Hospitals, and Cancer Hospital Research Institute, Gwalior, comprises of 60 consecutive patients who presented with cervical spine injury. All patients underwent a comprehensive Conventional Radiographic examination and subsequently MR Imaging at C.H.R.I., Gwalior on 0.3T, MR unit (Hitachi-AIRIS) within 72 hrs of injury. All patients were treated conservatively. The patients were divided into two subgroups - one with spinal cord injury without any abnormality as assessed by conventional radiography i.e. SCRWORA and the other with obvious abnormality on X-rays.
MR Imaging was significantly better than Conventional Radiography in assessement of pre- and para-vertebral hemorrhage, and damage to Anterior. Posterior and Interspinous ligaments MR Imaging also was significantly better than X-rays in depicting chronic changes like end plate marrow changes, disc spondylosis, canal stenosis and focal disc herniation. Cord edema and Disc herniation with or without edema were the two most common findings on MR Imaging of the injured spinal cord. While all cases with 9 segments (20%) in SCIWORA group. Spinal Cord Injury with Bony Injury group over all shows much less neurological improvement as compared to SCIWORA group. If 2 grades on Benzel and Larsen's grade, fair if improvement was 1 or 2 grades only and poor if the grade at the time of discharge remained unchanged or even deteriorated.
Though MR depicted all of the Soft Tissue injuries, it lacked such sensitivity in depicting skeletal abnormalities like Acute fracture (76% as compared to 96% on conventional Radiography). Acute facet subluxation or dislocation (71% as compared to 86% on Conventional Radiography), acute vertebral subluxation or dislocation (84% as compared to 96% on Conventional Radiography) [Table 4].
The statistical assessment of MR imaging versus Conventional Radiography in Cervical Spine and Patients with spondylotic changes shows the MR imaging was significantly better for evaluation of canal stenosis and for focal disc herniation. On the other hand Conventional Radiography was superior for detection of degenerative subluxation and facet spondylosis [Table 5].
In SCIWORA cases, cord edema was the most common finding on MR imaging of Spinal Cord [Table 6].
A significant number of Patients were discharged at a higher grade (according to Benzel and Larsen grade) in SCIWORA group as compared to Spinal Cord Injury with Bony Injury group postulating that morbidity was more in the latter group [Table 7].
When examining the relationship between the number of segments involved and improvement in neurological status as assessed by Benzel and Larsen grade at the time of admission and discharge, improvement was more likely when <4 segments were involved and less likely as more segments were affected [Table 8].
Methyl prednisolone therapy improves prognosis in SCIWORA patients if given within 8 hours of injury [Table 8].
Prognosis was poorer in Spinal Cord Injury with bony injury when compared to SCIWORA Patients [Table 10].
Management of severe injury to the vertebral column is a frequently encountered problem in a Regional Trauma center. The particular vulnerability of the Cervical Spine has been stressed . Conventional radiography is generally used to diagnose acute injury in the Emergency Department but is far from being sensitive enough to detect all injuries. This discrepancy led to a greater use of CT scanning in assessment of acute spinal trauma but CT imaging has certain drawbacks that have prompted the use of MR Examination is axial plane frequently misses horizontal fractures which are a particular problem at C2 level. subluxation can be inferred but is not seen directly without sagittal reformatting. In case of penetrating trauma, streak artifacts can result from bullet fragments. In one series of 23 cases in which CT scans were obtained without intrathecal contrast, intra spinal soft tissue was inadequately demonstrated in 22 patients . Lesions missed included cord transection, dural tears, nerve root avulsions, herniated discs and cord contusion.
These limitations have led to use of CT with intrathecal enhancement as a means of establishing the presence of canal encroachment or cord compression following acute trauma. But CT myelography is not without its disadvantages. The technical aspects of C1-2 punctures are readily mastered with experience, but performing the procedure on an acutely injured patient in supine position is difficult. Complications, though rare, are not unheard of . Therefore, fewer myelograms are performed for this indication.
Because MR can demonstrate compressive lesions of spinal cord without intrathecal contrast, so this technique is preferred (after plain radiographs) in any patient with a neurologic deficit following Acute Cervical Spine trauma . Conventional Radiography and CT findings have been suggested to have little correlation with patient's neurological status and thus are of little or no prognostic value.
Findings in this prospective assessment of Cervical Spine Trauma support the potential clinical utility of middle field strength MR imaging as the initial diagnostic assessment of injury. Finding at MR imaging were comparable to those at Conventional Radiography for acute fracture and were superior for evaluation of prevertebral hemorrhage or edema, paravertebral hemorrhage or edema. Anterior Longitudinal Ligament injury, Posterior Longitudinal Ligament injury, traumatic disc herniation, cord edema, cord compression, canal stenosis and focal disc herniation. The findings suggest that MR imaging may be complimentary to Conventional Radiography for detection of osseous injury.
MR should be considered the standard of reference in the detection of soft tissue injury associated with cervical spine trauma ,,, and . Previous investigators have described MR imaging patterns of spinal cord injury and compared them with patient neurologic status ,  and . The observations reflect a combination of cord swelling, cord edema, cord hemorrhage and cord compression. Simple cord edema was the most common cord injury pattern described ,  as in this study [Table 11]. The patterns described using MR imaging at 1.5 T suggested a high degree of correlation between three cord injury patterns and patient outcome. The first pattern described is edema due to only contusion, with indicates a more favorable prognosis with potential for reversibility. The second pattern is of blood alone, with indicates a more substantial axonal injury and much less potential for reversibility. The third pattern is a mixed pattern of blood and edema, which indicates an intermediate prognosis with some potential for recovery . The cranio-caudal length of segment of abnormal cord signal intensity from contusion has been correlated with prognosis . The results indicate that if cord contusion is greater than one vertebral level in length the prognosis is less favorable. This study corroborates the results.
Spinal cord injury without radiological abnormality (SCIWORA) is a syndrome of cervical spinal cord trauma, describing post traumatic myelopathy without evidence of vertebral fracture of malalignment on plain radiographs or on CT. The injury is predominantly documented in children, probably due to increased elasticity of pediatric spine. It appears that strain of the cervical spine in any direction can injure the cord. In hyperextension, the cord gets damaged due to compression, while in hyper flexion, rotatory acceleration and distraction, injury occurs due to combination of stretching, tethering and vascular compromise. With increasing utilization of MRI in the evaluation of traumatic myelopathy, more cases of SCIWORA can be discovered. Management is conservative and outcome is not as dismal as seen in injuries with cervical fracture or dislocation .
If the radiographs are declared negative, it is a routine to assess for evidence of instability which can result from fracture alone, ligament disruption alone or a combination of those injuries. Clinical instability is defined as inability to maintain normal associations between vertebrae while under a physiologic load . As instability may lead to subsequent injury to Spinal Cord or nerve roots or substantial pain or deformity, it should prompt consideration of an MR imaging assessment. If instability is suggested on radiographs, further evaluation with flexion - extension radiography may be performed but is unreliable . Because Cervical Spine, including the cervico-thoracic junction is not routinely visible and MR imaging allows direct visualization of not only morphologic changes within bones and soft tissues, including ligaments but also of signal intensity abnormality usually due to edema or blood, one should make use of multiplanar capabilities of MR imaging for excellent assessment of Anterior Longitudinal Ligament, Posterior Longitudinal Ligament and flaval ligaments which are believed to provide stability.
Post traumatic disc herniation is demonstrated exceptionally well on MR and was depicted at 35 levels in 18 patients. None of these were depicted on Conventional Radiography. Secondary findings of cervical disc damage include increased signal intensity of injured disc on T2 WI which possibly represent edematous changes and presence of associated injuries to paraspinal soft tissues or Spinal Cord at the same level. However, the presence of a herniated disc fragment does not necessarily imply a deleterious clinical consequence .
The relation between preexistent Cervical Spine skeletal abnormalities such as spondylosis, central canal stenosis and acute fracture and cord or ligament injury is controversial . A significant number of patients in the study had occurrence of cord injury in conditions of underlying spondylosis, central canal stenosis and acute fracture.
Patent with spondylosis who have hyperextension injury are at higher risk of Central Cord Syndrome . The mechanism leading to central cord injury is posterior disc bulging and anterior buckling of hypertrophied flaval ligaments with hyperextension. The central gray matter and adjacent tracts are injured, which accounts for the predominance of weakness in upper extremities and the eventual decrease is pain and temperature sensation. These injuries may be radiographically occult . MR imaging can demonstrate injury to spinal cord and ligament injury or disc injury, such as fracture through disc or disc extrusion.
Methylprednisolone improve the outcome if it is administered within 8 hours of injury. (Dose bolus 30 mg/kg body wt. Followed by 5.4 mg/kg body wt. Per hour for 23 hours .
In conclusion, MR can be employed in acute cervical trauma to demonstrate fracture-dislocations as well as to delineate soft tissue pathologic states. We feel confident in predicting interruptin of Anterior, Posterior and Interspinous ligaments and also herniation of intervertebral disc. Assessment of the number of segments of the spinal cord involved, by MR Imaging is helpful in predicting the prognosis of the patient.
The authors wish to acknowledge the help extended by Dr. S. N. Lyenger, Dr. B. R. Srivastava and Dr. S. K. Gupta in preparation of the manuscript and Likhar Computers for their meticulous typing.
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