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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


Dept. of Radiodiagnosis, G.R. Medical College, Gwalior, India

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Keywords: Spinal Injuries, Cervical Spine, MRI

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 Oct 23];14:71-80. Available from: http://www.ijri.org/text.asp?2004/14/1/71/28561

   Purpose of Study Top


  1. To determine the role of MRI in prospective detection of acute cervical spine injury.
  2. To compare the findings of MR Imaging with those of a comprehensive Conventional Radiographic assessment.
  3. To assess factors which affect outcome in patients with Cervical Spinal Cord Injury.
  4. 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 Top


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.


   Results Top


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 <4 segments of spinal cord involved improved neurologically, only one out of five patients improved with involvement of >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 < 4 segments were involved, 66.6% of patients showed improvement (2 out of 3 patients) while in involvement of 4-9 segments, almost 50% showed improvement. Neurological status improved only in 25% (4 out of 16 patients) when more than 9 segments were involved. While 14 patients out of 25 in SCIWORA group showed a good outcome, such was not the case in Spinal Cord Injury with Bony Injury group as only 7 out of 35 patients showed good outcome in this group. Most patients in Spinal Cord Injury with Bony Injury group (n=13) had poor prognosis. 6 patients died in this group as compared is 2 patients in SCIWORA group. All these reflect a poorer prognosis in Spinal Cord Injury with Bony Injury group when compared to SCIWORA group. Methylprednisolone therapy improved the outcome in patients with SCIWORA.

MR Imaging is the most sensitive modality for prospective detection of cervical spine injuries. MR can be employed in acute cervical trauma to demonstrate fracture-dislocations as well as to delineate soft tissue pathologies. We feel confident in predicting interruption of Anterior, Posterior and Interspinous ligaments and also herniation of intervertebral disc. These factors are important to Neurosurgeons and Orthopedic surgeons in planning management. There certainly seems to be a niche for MRI in Acute Cervical Trauma.


   Introduction Top


The Edwin Smith surgical papyrus, written 5,000 years ago, describes Cervical Spinal Cord Injuries as ailments not to be treated. Such pessimistic views survived until the "Golden Era" of Greece when more modern teachings in Medicine were introduced. Hippocrates is cedited with much of the advancement in the treatment of spinal injuries

In most countries, acute spinal cord injury occurs at an annual rate of 20-40 persons per million[1]. The main causes of spinal cord trauma are motor vehicle accidents, sports and recreational activities, accidents at work and falls at home [2]. With the possible exception of Methylprednisolone, there is no effective means of restoring neurological function below the level of a complete lesion [3].

Only very limited clinical evaluation of cervical spinal trauma has been done with MR Imaging. Also to minimize the possibility of failure to diagnose occult injuries, it has become standard practice in many centers to perform conventional radiographic studies in all patients admitted with a history of substantial blunt trauma. The use of this diagnostic modality alone because conventional radiographs generally are positive is only about 2-5% of patients in this clinical setting [4].

MR imaging, with use of systems with either high or low field strength, is of increasing utility is evaluation of acute injuries to the Cervical Spine. [5]. This is inspite of the fact that for long MR imaging has been perceived as being incompatible with the unpredictable clinical status and intensive monitoring requirements for patients in the Emergency Department. However, MR imaginag provides unparalled multiplanar depiction of Soft tissue injury, including ligament damage, intervertebral disc herniation, Spinal Cord Injury and prevertebral and paravertebral hemorrhage and edema after blunt Cervical Spine Injuries. Because MR imaging is not routinely used in most trauma centers, its utility as a frontline diagnostic modality is not settled.

This prospective study, performed prior to spinal injury reduction, was undertaken to assess the contribution of MR imaging at 0.3 T in evaluation of Acute Cervical Spine trauma with neurologic injury, compared with that of a traditional comprehensive conventional radiographic studies. The study assesses the factors that affect the outcome in patients with Cervical Spine Injuries and also prognosis of Cervical Spine Injuries with bony injury to SCIWORA (Spinal Cord Injury without radiographic abnormality).


   Materials and Methods Top


The patients presenting to the Emergency department with likelihood of Cervical Spine Injuries on the basis of history and physical examination, were admitted to the Department of Neurosurgery. Specific criteria to this group were - neurologic deficits referable to cervical spinal cord or roots, fracture of Cervical Spine and evaluation of possible associated ligament injury, traumatic disc extrusion or occult osseous or ligament injury at other levels, subluxation of Cervical Spine and assessment of associated ligament injury or traumatic disc extrusion at the level of subluxation or associated Injury at any other cervical level, unexplained severe post traumatic neck pain and need for "clearance of Cervical Spine" following major trauma in patient with altered level of consciousness.

Detailed History was taken. Neurological examination was done in detail including motor and sensory system examination. Patients were grouped according to Neurological grading system (Benzel and Larson 1987) into categories depending upon their neurological status [Table - 1]. Neurological examination was done on admission, third, seventh day and at time of discharged and out come was assessed according to improvement in the Benzel and Larsen grade.

In an attempt to avoid misdiagnosis of clinically occult injuries, initial radiological assessment of patients who have suffered major trauma was performed with use of established protocol (Prescribed sequences of radiologic studies that are obtained on all patients regardless of clinical presentation). All patients underwent a comprehensive conventional radiographic assessment with following projections: Lateral Swimmer's, AP, open mouth odontoid, Fuch's odontoid and both posterior oblique projections. Additional radiographs were acquired as deemed necessary.

All MR images of Cervical Spine Injury patients were obtained as soon as possible after the initial conventional radiographic was done. Most patients underwent MR imaging within twelve hours of presentation and 95% within twenty four hours. Patients who were hemodynamically unstable or those requiring immediate interventional procedures were considered for delayed imaging but they still underwent imaging within 72 hours of admission to hospital.

All patients were examined with use of 0.3 T MR imaging unit (MRP 7000, AIRIS, Hitachi, Tokyo). Imaging was performed with a minimum of two sequences: Sagittal T1W (510/25 TR/TE in msec) and T2W (4000/117, TR/TE in msec). Slice thickness was 4 mm with a 1 mm gap. If any abnormalities were identified additional axial T1W images were obtained.

CT was used only in a few cases to further assess the possibility or to further classify the extent of osseous abnormalities.

With use of each vertebral level as unit of observation, an anatomic location was defined as the portion of the closest vertebra that intersected a horizontal lined drawn through the abnormality. Locations were thus established and tabulated for the nearest vertebral level. If any component of a lesion extended to a continuous anatomic segment, then it was also tabulated to involve that segment [Figure - 1].

Parameters indicative of acute injury were assessed and tabulated for each of the eight spinal levels encompassing the first cervical (C1) to the first thoracic (T1) vertebra [Table - 2] and [Table - 3].

The patients of Cervical Spine Injuries were further subdivided into 2 groups:-

i) Without bony injury (SCIWORA)

ii) With bony injury

The patients who came within 8 hours of injury were given

methyl prednisolone according to standard protocol and further outcome was assessed in both the groups.

The outcome was graded as Good if the neurological improvement was >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.


   Results Top


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].


   Discussion Top


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 [7]. 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 [8]. 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 [9]. 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 [10]. 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 [6],[1],[12],[13] and [14]. Previous investigators have described MR imaging patterns of spinal cord injury and compared them with patient neurologic status [15], [16] and [17]. 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 [15], [16] 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 [18]. The cranio-caudal length of segment of abnormal cord signal intensity from contusion has been correlated with prognosis [19]. 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 [20].

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 [21]. 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 [22]. 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 [6].

The relation between preexistent Cervical Spine skeletal abnormalities such as spondylosis, central canal stenosis and acute fracture and cord or ligament injury is controversial [23]. 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 [24]. 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 [25]. 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 [26].

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.


   Acknowledgement Top


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.

 
   References Top

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2.Tator, C. H, Edmonds, V.E. Acute Spinal Cord Injury: analysis of Epidemologic factors. Candian J. of Surgery. 1979, 22 (6): 575-78.   Back to cited text no. 2    
3.Tator CH, Rowed DW, Schwartz ML et al : Management of acute spinal cord injuries. Can J Surg 27: 289-294, 1984.   Back to cited text no. 3    
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14.Benzel EC, Hart BL, Ball PA, et al . Magnetici resonance imaging for the evaluation of patients with occult cervical spine injury. J. Neurosurg. 1996; 85:824-829.   Back to cited text no. 14    
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20.Bhatoe HS. Cervical spinal cord injury without radiological Abnormality in Adults. Neurology India, Sept 2000; 243-8.   Back to cited text no. 20    
21.White AA, Southwick WO. Clinical instability in the lower cervical spine: a review of past and current concepts. Spine 1976; 1: 15-27.   Back to cited text no. 21    
22.Lewis LM, Docherty M, Ruoff BE, Fortney JP, Keltner RA, Jr. Britton P. Flexion - extension views in the evaluation of cervical spine injuries. Ann Emerg Med 1991; 20: 117-121.   Back to cited text no. 22    
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24.Regenbogen VS, Rogers LF, Atlas SE, Kim KS. Cervical spinal cord injuries in patients with cervical spondylosis. AJR 1986; 146: 277-284.   Back to cited text no. 24    
25.Cintron E, Gilula LA, Murphy WA, Gehweiler JA. The widened disc space: a sign of cervical hyperextension injury. Radiology 1981; 141: 639-644.   Back to cited text no. 25  [PUBMED]  
26.Bracken, M.B, Shepard, M. J, Willaim, F.C. et al . A randomized controlled trial of methyl prednisolone or naloxone in the treatment of acute spinal cord injury study. The New England Journal of Medicine 1990, 322 (2): 1405-11.   Back to cited text no. 26    

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Correspondence Address:
S Khandelwal
Dept. of Radiodiagnosis, G.R. Medical College, Gwalior
India
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Source of Support: None, Conflict of Interest: None


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    Figures

[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6]

    Tables

[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6], [Table - 7], [Table - 8], [Table - 9], [Table - 10], [Table - 11]

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