CT in the evaluation of spine trauma

Early imaging of spinal trauma

Spinal injury has the ability to maim and kill, but appropriate diagnosis and early treatment should result in minimization of secondary neurological injury and the restoration of the integrity of the spinal column. Rapid early diagnosis is essential and an impressive array of imaging technology is now available to the clinician. However, plain radiography remains the starting point for imaging of patients with potential spinal injury. This article reviews the role of plain radiography and the indications for further imaging, specifically with computerized tomography and magnetic resonance imaging.

Diagnostic abilities of magnetic resonance imaging in traumatic injury to the posterior ligamentous complex: the effect of years in training

BACKGROUND CONTEXT

The integrity of the posterior ligamentous complex (PLC) has been proposed to be an integral aspect in the treatment algorithm for spinal trauma. Magnetic resonance imaging (MRI) has been reported as the ideal tool to determine the integrity of the PLC. The ability to assess disruption of the PLC by reviewers of differing levels of training has not been described. In addition, the MRI sequence most suggestive of injury for each component of the PLC has not been clearly determined.

PURPOSE

This study was designed to determine the ability of reviewers with differing levels of training (fellowship-trained spine surgeon, fellowship-trained musculoskeletal radiologist, senior orthopedic surgery resident, and junior orthopedic surgery resident) to accurately interpret the results of MRI. The secondary purpose was to evaluate the MRI sequence that was most indicative of injury to the components of the PLC.

STUDY DESIGN

This is a prospective radiological study comparing reviewers of MRI to determine integrity of the PLC components using intraoperative notation as the gold standard for integrity.

PATIENT SAMPLE

Forty-five consecutive spinal trauma patients who underwent operative fixation after obtaining MRI.

OUTCOME MEASURES

No patient outcome measures were used.

METHODS

The sensitivity, specificity, and accuracy for each MRI reviewer in regard to MRI integrity were compared with the gold standard of intraoperative observation. In addition, the MRI sequence most suggestive of integrity of the PLC was noted by each reviewer for each component of the PLC.

RESULTS

Forty-five patients (29 men and 16 women) with traumatic spine injuries were enrolled in the study. The sensitivity and accuracy of the surgeon were 0.83 (0.66, 0.92) and 0.81 (0.70, 0.88), respectively. The sensitivity and accuracy of the attending spine surgeon were not statistically significantly different from the other reviewers (p value=.2317 and .2582). However, the specificity of the surgeon was statistically significantly higher than that of the other reviewers (p=.0043). In the cervical, thoracic, and lumbar spine, the reviewers reached a 93% agreement that the sagittal short-tau inversion recovery (STIR) sequences were most helpful in visualizing injury to the supraspinous ligament (SSL), interspinous ligament (ISL), ligamentum flavum (LF), and the cervical facet capsules. The reviewers attained a 95% agreement that visualization of injury to the lumbar facet capsules is most optimal in the T2 axial sequences.

CONCLUSIONS

The interpretation of traumatic MRI is very sensitive and accurate regardless of years of training of the observer. The attending-level spine surgeon was statistically more specific in the evaluation of injury MRIs. The fluid-weighted STIR sagittal sequences are most useful in determining injury to the SSL, ISL, LF, and cervical facets capsules. Lumbar facet capsules are best evaluated with axial T2 MRI. The evaluation of the PLC on MRI can be accurately and efficiently interpreted by physicians at multiple levels of training, thus providing a key imaging modality in determining stability and need for stabilization.

Using magnetic resonance imaging to accurately assess injury to the posterior ligamentous complex of the spine: a prospective comparison of the surgeon and radiologist

Object

Magnetic resonance imaging has been proposed as a powerful technique for assessing the integrity of the posterior ligamentous complex (PLC) in spinal trauma. Because MR imaging is often used to determine appropriate treatment, it is important to determine the accuracy and reliability of MR imaging in diagnosing PLC disruption. The purpose of this study is to compare the ability of the radiologist and surgeon to assess disruption of the PLC in the setting of acute cervical and thoracolumbar trauma using MR imaging.

Methods

The components of the PLC in 89 consecutive patients with cervical or thoracolumbar fractures following acute spinal trauma were evaluated using MR imaging by both a musculoskeletal radiologist and an independent spine surgeon and assessed intraoperatively under direct visualization by the treating surgeon. The MR imaging interpretations of the musculoskeletal radiologist and surgeon were compared with the intraoperative report for accuracy, sensitivity, specificity, and positive and negative predictive values. A comparison between the radiologist's and spine surgeon's accuracy of MR imaging interpretation was performed.

Results

The agreement between both the spine surgeon's and radiologist's MR imaging interpretation and the actual intraoperative findings was moderate for most components of the PLC. Overall, the MR imaging interpretation of the surgeon was more accurate than that of the radiologist. The interpretation of MR imaging by the surgeon had negative predictive value and sensitivity of up to 100%. However, the specificity of MR imaging for both the surgeon and radiologist was lower, ranging from 51.5 to 80.5%.

Conclusions

Comparison of the MR imaging interpretations between surgeon and radiologist indicates that the surgeon was more accurate for some PLC components. The relatively low positive predictive value and specificity for MR imaging in assessing PLC integrity suggests that both the surgeon and radiologist tend to overdiagnose PLC injury using MR imaging. This can lead to unnecessary surgeries if only MR imaging is used for treatment decision making.

Practice management guidelines for the screening of thoracolumbar spine fracture

BACKGROUND

Fractures to the thoracolumbar spine (TLS) commonly occur because of major trauma mechanisms. In one series, 4.4% of all patients arriving at a Level I trauma center were diagnosed as having TLS fracture. Approximately 19% to 50% of these fractures in the TLS region will be associated with neurologic damage to the spinal cord. To date there are no randomized studies and only a few prospective studies specifically addressing the subject. The Eastern Association for the Surgery of Trauma organization Practice Management Guidelines committee set out to develop an EBM guideline for the diagnosis of TLS fractures.

METHODS

A computerized search of the National Library of Medicine and the National Institutes of Health MEDLINE database was undertaken using the PubMed Entrez (www.pubmed.gov) interface. The primary search strategy was developed to retrieve English language articles focusing on diagnostic examination of potential TLS injury published between 1995 and March 2005. Articles were screened based on the following questions. (1) Does a patient who is awake, nonintoxicated, without distracting injuries require radiographic workup or a clinical examination only? (2) Does a patient with a distracting injury, altered mental status, or pain require radiographic examination? (3) Does the obtunded patient require radiographic examination?

RESULTS

Sixty-nine articles were identified after the initial screening process, all of which dealt with blunt injury to the TLS, along with clinical, radiographic, fluoroscopic, and magnetic resonance imaging evaluation. From this group, 32 articles were selected. The reviewers identified 27 articles that dealt with the initial evaluation of TLS injury after trauma.

CONCLUSION

Computed tomography (CT) scan imaging of the bony spine has advanced with helical and currently multidetector images to allow reformatted axial collimation of images into two-dimensional and three-dimensional images. As a result, bony injuries to the TLS are commonly being identified. Most blunt trauma patients require CT to screen for other injuries. This has allowed the single admitting series of CT scans to also include screening for bony spine injuries. However, all of the publications fail to clearly define the criteria used to decide who gets radiographs or CT scans. No study has carefully conducted long-term follow-up on all of their trauma patients to identify all cases of TLS injury missed in the acute setting.

Visceral Torso Computed Tomography for Clearance of the Thoracolumbar Spine in Trauma: A Review of the Literature

BACKGROUND

Accurate screening of the thoracolumbar spine (TLS) remains problematic in the care of trauma patients. The current standard of care for TLS screening is not clearly defined. In trauma patients undergoing computed tomography (CT) of the chest and or abdomen, compelling supportive evidence for reformatting and reusing this CT data to clear the thoracolumbar spine has accumulated over the last 3 years. The objective of this review was to identify and review all published studies comparing reformatted CT to traditional plain radiography for TLS clearance.

METHODS

A Medline search for all English language articles published on this subject since 1980 identified seven studies. Each was classified according to the levels of evidence classification of the Agency for Health Care Policy and Research. The methodology of each study was reviewed for the CT protocol, utilization of radiologist blinding and whether historical dictated reports or de novo image readings were used for comparison. The sensitivity and specificity of each study and the gold standard utilized in its calculation was noted. Where available, detailed information regarding the missed injuries and their clinical relevance was abstracted for each study.

RESULTS

All evaluated studies demonstrated superior sensitivity and interobserver variability for reformatted CT compared with plain radiographic screening. CT was also more accurate in localizing, classifying, and delineating the age, bony intrusion, and soft-tissue damage associated with the fracture. For studies with time-motion components, a protocol utilizing CT clearance was not only more accurate but faster and more economical. Screening with reformatted visceral CT data required no additional scan time or radiation exposure.

CONCLUSION

The evidence to date demonstrates the superior sensitivity of reformatted visceral CT for detecting thoracolumbar spine injury. With no further patient movement, radiation exposure, cost, or time, trauma patients undergoing visceral CT can have their thoracolumbar spine promptly evaluated. Further prospective evaluation of the CT protocols to optimize visualization of both the viscera and the bone is warranted.

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.

Multislice CT in imaging of trauma of the spine, pelvis and complex foot injuries

Multislice CT (MSCT) has greatly enhanced the performance of CT scanners and has vastly improved imaging of musculoskeletal trauma. Fast, high resolution scanning is now possible. In our institution, MSCT is an essential part of the imaging of the traumatized patient. The advantages of volume imaging, such as multiplanar reconstructions (MPRs) with near isotropic viewing, three-dimensional imaging and thick slice (wedge) MPRs (mimicking conventional radiographs), enable more accurate assessment of complex anatomical areas such as the spine, pelvis and foot. We discuss the general principles of scanning for musculoskeletal trauma and describe our experience of MSCT of the traumatized spine, pelvis and foot.

Thoracolumbar spine fractures in patients who have sustained severe trauma: depiction with multi-detector row CT

PURPOSE

To determine if multi-detector row computed tomography (CT) can replace conventional radiography and be performed alone in severe trauma patients for the depiction of thoracolumbar spine fractures.

MATERIALS AND METHODS

One hundred consecutive severe trauma patients who underwent conventional radiography of the thoracolumbar spine as well as thoracoabdominal multi-detector row CT were prospectively identified. Conventional radiographs were reviewed independently by three radiologists and two orthopedic surgeons; CT images were reviewed by three radiologists. Reviewers were blinded both to one another's reviews and to the results of initial evaluation. Presence, location, and stability of fractures, as well as quality of reviewed images, were assessed. Statistical analysis was performed to determine sensitivity and interobserver agreement for each procedure, with results of clinical and radiologic follow-up as the standard of reference. The time to perform each examination and the radiation dose involved were evaluated. A resource cost analysis was performed.

RESULTS

Sixty-seven fractured vertebrae were diagnosed in 26 patients. Twelve patients had unstable spine fractures. Mean sensitivity and interobserver agreement, respectively, for detection of unstable fractures were 97.2% and 0.951 for multi-detector row CT and 33.3% and 0.368 for conventional radiography. The median times to perform a conventional radiographic and a multi-detector row CT examination, respectively, were 33 and 40 minutes. Effective radiation doses at conventional radiography of the spine and thoracoabdominal multi-detector row CT, respectively, were 6.36 mSv and 19.42 mSv. Multi-detector row CT enabled identification of 146 associated traumatic lesions. The costs of conventional radiography and multi-detector row CT, respectively, were 145 and 880 US dollars per patient.

CONCLUSION

Multi-detector row CT is a better examination for depicting spine fractures than conventional radiography. It can replace conventional radiography and be performed alone in patients who have sustained severe trauma.

Feasibility of ultrasound examination in posterior ligament complex injury of thoracolumbar spine fracture

STUDY DESIGN

A prospective study of 12 patients with thoracolumbar spinal fractures was conducted.

OBJECTIVE

To assess the feasibility of ultrasound examination for posterior ligament complex injury in thoracolumbar spinal fractures.

SUMMARY OF BACKGROUND DATA

In posterior ligament complex injury of thoracolumbar spine fracture, the reliability of magnetic resonance imaging (MRI) for diagnosis has been reported. Nevertheless the usefulness of ultrasound for diagnosis has not been studied, whereas diagnostic ultrasound has been applied in the musculoskeletal system.

METHODS

Two healthy volunteers without a history of spinal trauma were recruited for pilot examination of the ultrasound procedure to access normal findings of the posterior ligament complex. This study investigated 12 thoracolumbar spine fractures. Four were flexion distraction injury; six were stable or unstable burst fractures; and two were simple compression fractures. Osteoporotic spine fractures were excluded from this study. Ultrasound was performed over the injured area by an experienced musculoskeletal radiologist in addition to radiography and MRI. Five patients underwent operative procedures to stabilize the fractured spine. Imaging data and operative findings were correlated with ultrasound examination.

RESULTS

In the patients who did not undergo surgery, agreement in diagnosis between MRI and ultrasound was moderate (5 of 7). Difficulty evaluating ligament status was encountered when the region of interest was the lower thoracic level (T10, T11, T12) because of long overlapping spinous processes. In the patients who underwent surgery, correlation between MRI, ultrasound, and operative findings was excellent, especially in diagnosing the status of the supraspinous and interspinous ligaments. Nevertheless, it is impossible to visualize deep-seated structures (i.e., ligamentum flavum, deep muscles of the spine, and facet joint) with ultrasound.

CONCLUSIONS

This study demonstrated the excellent diagnostic ability of ultrasound to detect the status of the supraspinous and interspinous ligaments, especially in patients who undergo surgery. Although ultrasound examination appears to be less sensitive than MRI in predicting ligament status, the cost effectiveness of ultrasound and its use as an alternative to MRI in special situations (i.e., patients with pacemaker, ferromagnetic implant, or severe claustrophobia) should be emphasized. More clinical data concerning the sensitivity, specificity, and accuracy of ultrasound examination should be addressed in future studies.

Evaluation of the acute cervical spine: a management algorithm

BACKGROUND

Safe, efficient, and cost-effective evaluation of the spine is the goal in the trauma setting. At our Level I trauma facility, the trauma service, emergency medicine, radiology, anesthesia, and the spine service combined individual concerns into one agreed-upon clearance protocol. Here, we present the effectiveness of a new cervical spine clearance protocol.

METHODS

A retrospective review was initiated of all trauma patients evaluated in a Level I trauma center the year before and after implementation of a new cervical spine protocol to determine the incidence of missed cervical injuries. An additional 6 months were reviewed to detect any missed injuries late in the study period.

RESULTS

During the 2-year study period, 4,460 patients presented to the emergency room with some form of cervical spine precautions. Blunt trauma comprised 90% of the study population. According to the protocol, approximately 45% required further cervical radiographs after presentation. In the preprotocol year, 77 of 2,217 (3.4%) patients were diagnosed with cervical spine injuries, 16 of 77 (21%) with multiple level of injuries, and 25 of 77 (32%) with neurologic compromise. Three of 2,217 patients had missed cervical spine injuries on their initial evaluations. In the postprotocol year, 84 of 2,243 (3.4%) patients had cervical injuries, 25 of 84 (30%) with multiple levels of injuries and 28 of 84 (28%) with neurologic compromise. No patient evaluated during the protocol year was missed. All statistics between the two groups were not significant.

CONCLUSION

The current protocol by risk stratifying patients on presentation is effective in assessing patients for cervical spine injuries.

Reliability of magnetic resonance imaging in detecting posterior ligament complex injury in thoracolumbar spinal fractures

STUDY DESIGN

Prospective study of 34 patients with thoracolumbar spinal fractures.

OBJECTIVES

To assess the reliability of magnetic resonance imaging (MRI) for posterior ligament complex injury in thoracolumbar spinal fractures.

SUMMARY OF BACKGROUND DATA

Some researchers have studied posterior ligament complex injury in spinal fracture using MRI. However, most did not evaluate the findings of MRI compared with the operative findings.

METHODS

Thirty-four patients with thoracolumbar spinal fracture were evaluated by palpation of the interspinous gap, plain radiography, and MRI before operation. In addition to conventional MRI sequences, a fat-suppressed T2-weighted sagittal sequence was performed. Surgery was performed by a posterior approach. During the operation, posterior ligament complex injury was carefully examined.

RESULTS

A wide interspinous gap was palpated in 14 patients and was found in 21 patients on plain radiography. Magnetic resonance imaging raised suspicion of injury to the posterior ligament complex in 30 patients. According to interpretation of MRI, injury to the supraspinous ligament was suspected in 27 patients, the interspinous ligament in 30 patients, and the ligamentum flavum in 9 patients. There were 28 supraspinous ligament injuries, 29 interspinous ligament injuries, and 7 ligamentum flavum injuries in operative findings. There was a significant relation between MRI interpretation and operative findings.

CONCLUSION

A fat-suppressed T2-weighted sagittal sequence of MRI was a highly sensitive, specific, and accurate method of evaluating posterior ligament complex injury. Based on the results of this study, a fat-suppressed T2-weighted sagittal sequence of MRIs is recommended for the accurate evaluation of posterior ligament complex injury and would be helpful in the selection of treatment options.

Computed tomographic scanning of cervical spine fractures: does it influence treatment?

OBJECTIVE

To determine whether the superior sensitivity of computed tomography (CT) results in changes in treatment plans for cervical spine fractures that have been diagnosed on plain films alone.

DESIGN

Retrospective review of radiographic studies for cervical spine trauma.

SETTING/PARTICIPANTS

An orthopaedic spine surgeon (SS), an orthopaedic traumatologist (OT), an orthopaedic spine fellow (SF), and an orthopaedic chief resident (CR) were independently presented thirty-nine cases of cervical spine trauma imaged with adequate plain radiographs and with CT.

MAIN OUTCOME MEASURES

Agreement was measured by calculation of kappa coefficients.

RESULTS

The detection rate of total fractures on plain radiographs alone ranged from 47 percent to 71 percent, and the diagnosis changed an average 53 percent of cases. Change in treatment plans ranged from 10 percent (SS) to 46 percent (CR) of cases. Of these changes, undertreatment occurred as follows: SS =3 percent, OT =8 percent, SF =36 percent, and CR = 46 percent. The mean kappa coefficient for intraobserver agreement of treatment plans was 0.69. The experienced observers demonstrated "excellent" agreement with an average kappa coefficient of 0.85, whereas the mean coefficient for inexperienced observers was 0.54 or "moderate" agreement. Complete diagnostic agreement occurred between the experienced observers after review of both the plain films and CT scans. The interobserver agreement of treatment plans for the experienced observers increased from 0.79 to 0.88.

CONCLUSIONS

CT scanning afforded additional information for all observers. Experienced observers can reliably determine treatment plans for cervical spine trauma diagnosed on plain films alone, whereas inexperienced observers are less reliable. For the experienced observers, interobserver agreement on treatment plans increased after the addition of CT.

Epstein-Barr virus involvement in gastric cancer: biomarker for lymph node metastasis

EBV involvement in gastric cancer is characterized by episomal monoclonality, high antibody titers, EBV encoded small RNA and EBV nuclear antigen 1 expression in all tumor cells, and in the intramucosal stage, by a unique morphology. EBV involvement varies by population (approximately 7% of gastric cancers in Japan and >15% in Western countries), sex, histological type, and tumor location. The present study compares frequency of lymph node metastasis (LNM) between 170 EBV-positive and 1590 EBV-negative gastric cancer cases in Japan by level of invasiveness. Frequency of LNM increased with increasing depth of invasiveness but was consistently and significantly greater for EBV-negative cases (P = 0.0018). In particular, there were no instances of LNM among 75 EBV-positive cases as compared with 53 among 562 EBV-negative cases restricted to the mucosa and submucosa (odds ratio, 0; 95% confidence limits, 0-0.20). The finding suggests that genetic control of metastasis may differ between EBV-related and other gastric cancers. Also, the possibility that EBV-positive, noninvasive gastric cancers may not require lymph node dissection suggests that routine assay of biopsy specimens for EBV involvement could be important in populations, like that of Japan, where early gastric cancers are seen frequently.

'Clearing' cervical spine injuries in polytrauma patients: is it really safe to remove the collar?

Polytrauma patients are at increased risk for occult cervical spine injuries. Those unable to provide clinical clues to injury either remain in hard collars until they are able to cooperate with the physical examination or are deemed "clear of cervical injury" if the emergency room screening radiographs are without obvious bony abnormality. Cervical immobilization for a lengthy period of time is not without morbidity. Missed ligamentous injuries can lead to cervical instability, which in turn can result in permanent neurologic sequelae. This article reviews the current methodologies to "clear the cervical spine" and highlights the inadequacies.

Sagittal vertebral body fractures: magnetic resonance imaging features

Isolated sagittal vertebral body fractures are rare and the plain radiographic diagnosis may be difficult. We report two cases, confirmed by CT, and describe the subtle MRI features which comprised increased signal intensity only on the midline sagittal T2 weighted images. In one case, the information from MRI significantly altered the patient's management by leading to a change from surgical to conservative treatment.

Three-dimensional computed tomographic imaging in the diagnosis of vertebral column trauma: experience based on 21 patients and review of the literature

OBJECTIVE

To compare standard x-ray films, two-dimensional computed tomographic reconstructions and three-dimensional (3-D) computed tomographic reconstructions for assessing the grade, extent, and severity of vertebral fracture.

PATIENTS AND METHODS

3-D images were created from standard computed tomographic scans obtained using a General Electric PACE scanner. In 21 patients (17 men and four women) these images were obtained during both the acute phase and at long-term follow-up; there were six cervical, four dorsal, five dorso-lumbar, and six lumbar fractures.

RESULTS

The 3-D images supplied useful information in complex traumas with rotation and/or dislocation of the vertebral body and in cases with loss of spinal alignment. The 3-D images also proved to be useful as an adjunctive imaging method for evaluation of bone fusion integrity.

CONCLUSION

3-D images produced by recently available software provide a 3-D understanding much more readily than do multiple two-dimensional images. Because it would be very difficult to standardize this method of imaging, it seems best that the specialist (orthopedic surgeon, neurosurgeon, neuroradiologist) be present during the investigation to decide the viewing angles. An important limitation to this method is the presence of degenerative disease or osteoporosis, mainly in elderly patients.

Imaging of cervical spine trauma

The cervical spine, supporting such critical structures as the medulla, spinal cord, and cervical nerve roots, can be very challenging to image properly because of its complex structural anatomy and superimposition of bony and soft tissue parts. In this article, the use and value of the various modalities that image the cervical spine are discussed. Plain radiography remains the best screening tool in the initial evaluation of the cervical spine after trauma. Additional views, such as swimmer's, pillar and lateral flexion, and extension, often are helpful in certain circumstances.

Computed tomographic scans of minimally displaced type II odontoid fractures

OBJECTIVE

To determine the computed tomography (CT) appearance of minimally displaced type II odontoid fractures and the optimal protocols to evaluate these fractures by CT.

MATERIALS AND METHODS

The CT scans of five patients with minimally displaced type II odontoid fractures and 71 patients without odontoid pathology were reviewed for signs of fracture. A phantom consisting of a cadaver specimen with a type II odontoid fracture was evaluated with several protocols on four CT scanners. The protocols differed in slice thickness and reconstruction algorithm. Helical scanning was also performed, and parasagittal and coronal reformations were created from each image set.

MAIN RESULTS

Multiple cortical disruptions longer than 1 mm were demonstrated on the scans of all five patients with type II odontoid fractures. Only three of the 71 patients without odontoid fractures had multiple cortical disruptions, and none were longer than 1 mm. In the phantom study, thinner sections demonstrated cortical disruptions better than thicker sections. Similarly, images reconstructed with a bone reconstruction algorithm demonstrated the cortical disruptions better than images reconstructed with a soft-tissue reconstruction algorithm. Helical scans (1 mm thick) adequately demonstrated the reduced Type II odontoid fracture. Parasagittal and coronal reformations failed to demonstrate a fracture line through the base of the odontoid process on all image sets.

CONCLUSIONS

Cortical disruptions greater than 1 mm and multiple cortical disruptions may be the only findings of odontoid fractures and should suggest the diagnosis. Evaluation of potential type II odontoid fractures is improved as CT section thickness is reduced (down to 1 mm) and is also improved by use of a bone reconstruction algorithm. The apparent absence of a fracture line through the base of the odontoid process on parasagittal or coronal reformations does not rule out the diagnosis.

Efficacy of limited CT for nonvisualized lower cervical spine in patients with blunt trauma

Records of 100 patients with blunt injury and nonvisualization of C7 and T1 on cross-table lateral and swimmer's views were reviewed to evaluate the usefulness of limited computed tomographic (CT) scans in "clearing" the lower cervical vertebrae of injury. CT was deemed necessary and performed in all of these cases because the lower cervical spine could not be evaluated clinically or with plain radiographs. Ninety-seven of these 100 patients had normal findings on CT and only three patients showed cervical spine fractures. All three had isolated and stable fractures. Two of these patients had "clay-shoveler" fractures at C6 and C7, respectively, and one had a single laminar fracture at C7. All three patients were conservatively treated. This study emphasizes the value of clinical correlation in the evaluation of cervical spine trauma. When deemed necessary in symptomatic patients, CT is useful to exclude skeletal injury in the lower cervical spine thus avoiding delay in the patient's workup and unnecessary hospitalization, and expediting patient discharge. Lack of pain and neurological findings in nonintoxicated, conscious, and alert patients is generally not associated with significant soft tissue or skeletal injury.

Thoracic spine trauma

Thoracic spine fractures are most commonly flexion injuries resulting from vehicular accidents or falls. The initial evaluation of any multiple trauma victim should include AP and cross-table lateral radiographs of the thoracic spine. Conventional and computed axial tomography can add additional information regarding posterior element integrity and spinal canal encroachment. MRI can also be useful in that it directly images the effects of fractures on the spinal cord.

Acute spinal cord injury: magnetic resonance imaging correlated with myelopathy

Thirty-one patients (29 males and two females, 13-87 years of age (mean, 46.7 years] with acute spinal cord injury were studied by MR (magnetic resonance) imaging and the results were correlated with neurological findings. Magnetic resonance images were obtained with a 0.5 T superconductive MR scanner (Phillips Gyroscan S5). Initial imaging was performed within 24 hours after trauma in 13 patients, 1-7 days in 13 patients and 7-14 days in five patients. Twenty-six patients underwent follow-up examinations with MR imaging. Cord abnormalities including cord compression (23 patients), cord swelling (seven patients), and abnormal signal intensities on either T1 or T2-weighted images (26 patients) were observed on initial examination. Multivariate analysis showed that cord compression and abnormal intensities on T1-weighted images were important prognostic indicators. Hyperintensity on T2-weighted images was non-specific but correlated well with clinical recovery. Magnetic resonance imaging is useful in predicting the prognosis and for planning treatment following spinal cord injuries.

Cruciate paralysis: a clinical and radiographic analysis of injuries to the cervicomedullary junction

Fourteen patients with superior cervical spinal cord injuries and the clinical signs and symptoms of cruciate paralysis are presented. This rare injury pattern is characterized by weakness of the upper extremities with little or no compromise of lower-extremity function following trauma to the superior spinal cord. Anatomically, cruciate paralysis is thought to represent selective injury to descending corticospinal tracts as they decussate at the cervicomedullary junction. The clinical and radiographic findings of each patient are outlined and the incidence and natural history of the injury syndrome, including a review of the literature, are presented.

CT of the spine: are plain spine radiographs necessary?

This study was designed to determine whether plain radiographs added any information of clinical significance to the information provided by CT (computed tomography) and its standard digital radiographs in 100 patients presenting for CT of the lumbar spine and 46 patients presenting for cervical spine CT. In only three (3%) of the lumbar studies and two (4.3%) of the cervical studies did the plain radiographs add diagnostic information. The added diagnostic information did not affect patient management in all cases with indications other than trauma. Good quality oblique cervical spine digital radiographs were obtained in 10 cases simply by moving the tube and detectors to the 45 degrees and 135 degrees azimuths. The evidence from this study suggests that when a CT examination of lumbar or cervical spines is planned on a high resolution CT scanner for indications other than trauma, a conventional plain radiographic examination can be omitted in the first instance.

Somatosensory evoked potentials and neurological grades as predictors of outcome in acute spinal cord injury

An analysis of Motor Index score, pinprick sensory score, joint position sense score, somatosensory evoked potential (SSEP) grade in the ulnar (SSEPu) and posterior tibial (SSEPt) regions, and overall SSEP grade (mean SSEPu + t) was conducted in 36 patients with cervical spinal cord injuries to determine the relationship of these scores, both individually and in combination, to functional outcome (as determined using the Barthel Index) at 6 months after injury. The clinical and electrophysiological data were obtained on the same day within 2 weeks after injury. Nineteen patients underwent two SSEP tests 1 week apart within the first 3 weeks following injury in an attempt to identify mean SSEPu + t improvement. Somatosensory evoked potential grading was based on the presence or absence of the cortical evoked potential, the amplitude of the early cortically generated waveform (P22 or P37), and the interpeak latency across the lesion site. Mean SSEPu + t had the strongest individual relationship with outcome (R-square 0.75, p less than 0.0001) and mean SSEPu + t improvement over a 1-week interval during the first 3 weeks after injury was associated with Motor Index score improvement over a 6 month period. Joint position sense score was the best clinical predictor of outcome (R-square 0.64, p less than 0.0001). Mean SSEPu + t correlated with outcome more closely than the combination of Motor Index score and pinprick sensory score. Mean SSEPu + t in combination with all three clinical indicators produced the strongest correlation with outcome (R-square 0.87, p less than 0.0001). This study confirms the prognostic value of quantitative SSEP analysis for patients with acute spinal cord injuries.

Acute axis fractures: a review of 229 cases

Eighteen percent of acute cervical spine fractures involve the C-2 vertebra. The odontoid Type II fracture is the most common axis fracture and it is also the most difficult to treat. The degree of odontoid dislocation has been identified as the single most important fracture feature that helps separate those patients who have a high likelihood of healing with nonoperative therapy from those who are likely to fail nonoperative therapy and should be offered early surgical stabilization. The difference is statistically significant (p less than 0.001, x2 = 30.20). The present series includes 229 patients with acute axis fractures. Follow-up data were available in 92% of these patients, for a median duration of 4 years 9 months. Treatment guidelines and results are offered for each subtype of axis fracture based on this experience.

Computerized tomography after internal fixation of the spine

32 patients with internal fixation of the spine were postoperatively examined by computerized tomography. Details of metallic osteosynthetic material were demonstrated in all our cases. Bony structures were well defined in 27 patients, whereas soft tissue imaging was degraded by scattering artifacts in 14 of 20 examinations. Application of intrathecal contrast medium, however, was helpful for the evaluation of intraspinal soft tissues. Involvement of extraspinal soft tissues could be interpreted on the basis extent of vertebral osseous destruction.

CT of dens axis fractures

The distinction between the different types of dens axis fracture is important. Fractures at the base of dens (Type II) may be overlooked if reformated images are not made. If the fracture extends downward into the body of the vertebra (Type III), the body fragment may rotate into the spinal canal. The rotation is difficult to see on plain films, but is easily seen at axial CT.

Cervical spine fracture following a motor vehicle accident

We present the case of a 50-year-old man who visited our emergency department 12 h after an alcohol-related motor vehicle accident complaining of shoulder pain and neck stiffness. Cervical spine radiographs were obtained and interpreted as normal, and the patient was discharged. Subsequent review by a radiologist raised the question of a second cervical vertebra (C-2) abnormality, and the patient was recalled. Cervical computed tomography (CT) scan revealed an unstable oblique fracture of C-2 and a congenital nonfusion of the arch of C-1. The patient was placed in halo traction, and subsequent radiographs revealed a fracture of the transverse process of C-7. The patient made an uneventful recovery. The limitations of routine cervical radiographs are well-documented, but no feasible alternative exists as a screening procedure. Thus, a certain level of uncertainty must be accepted. Both physician and patient must recognize the limitations inherent in all medical practice and that follow-up examination and treatment are essential.

The impact of magnetic resonance on the diagnostic evaluation of acute cervicothoracic spinal trauma

From 1984 to 1987 magnetic resonance (MR) imaging was performed on 100 patients suffering acute spinal trauma. MR demonstrated one or more injuries to the cervicothoracic region in 31 patients. It displayed a spectrum of spinal cord injury ranging from mild compression and swelling to complete transection. MR was also useful in evaluating alignment at the cervicothoracic junction, in depicting ligamentous injury, in establishing the presence of disc herniation, and in identifying unsuspected levels of injury. We present a diagnostic algorithm that incorporates the role of MR in evaluating acute cervicothoracic spinal trauma and emphasizes the replacement of myelography by MR in the initial assessment of neurologic deficit.

Atlas fractures: treatment and long-term results

Fractures of the first cervical vertebra (C1) represent approximately 7% of all acute cervical spine fractures. Frequently, the atlas will be fractured in combination with the axis (44% of cases). Treatment of isolated C1 fractures should be governed by the rules of Spence. The treatment of combination C1-C2 fractures is dictated by the type and severity of the C2 fracture. Experience with 57 cases of acute traumatic atlas fractures are reviewed. The long-term outcome from an atlas fracture is good (median follow-up, 40 months).

Pediatric spinal trauma. Review of 122 cases of spinal cord and vertebral column injuries

A review of 122 pediatric cases of vertebral column and spinal cord injuries is presented. These relatively uncommon injuries can be characterized by four distinct injury patterns: fracture only, fracture with subluxation, subluxation only, and spinal cord injury without radiographic abnormality. The immature pediatric spine has several anatomical and biomechanical features that distinguish it from the mature adolescent spine and, accordingly, the frequency of the injury type, the level of spine injury, and the incidence of neurological compromise were found to vary with the age of the patient. Follow-up data were obtained in 93% of the cases (median duration 44 months). No patient was made worse by treatment, 89% of the patients with incomplete myelopathy on admission were improved on their last examination, and 20% of the patients with a complete myelopathy had evidence of significant recovery of function. The authors conclude that the outcome after pediatric spinal trauma is good.

Computerized tomography of injury to the thoracolumbar spine

We have reviewed the appearances of 35 patients with 51 fractures of the thoracic and lumbar spine who were seen over the past 3 years; all received plain film radiography and computerized tomography (CT). The types and distribution of fractures are similar to those in series already reported. The severity of each fracture can be described using a three-column model for the functional anatomy of the spine. The liability to orthopaedic instability or late neurological damage can be accurately assessed by computerized tomography. CT demonstrates many fractures of parts of vertebrae not seen on plain films. We propose a classification which is clinically relevant and simple.

Computed tomography in spinal trauma

In a retrospective study of 65 patients with spinal trauma, computed tomography was found to add to plain radiography clinically relevant information in 47 patients. It was most helpful in identifying unsuspected neural arch fractures and in assessing spinal canal narrowing. Computed tomography is of great value in pretreatment evaluation and in follow-up of the patient with significant spinal trauma.

Three dimensional imaging of bone from analysis of computed tomography data

A computer system was developed to reconstruct three dimensional images of bone from analysis of computed tomography data. Images of bone can be made within minutes and rotated for viewing from any direction. An editing process allows visualization of the articular surfaces of any joint. Solid models of the bone images can be produced with an accuracy of 1 mm to 3 mm by interfacing the image data with a computer numerically controlled milling machine. This technology will provide better information to the surgeon for preoperative diagnosis and planning and for the design of customized implants.

Evaluation of acute nonpenetrating cervical spinal cord injuries with CT metrizamide myelography

Computerized tomography metrizamide myelography was performed in 46 patients with acute, nonpenetrating cervical spinal cord injuries. By visualizing the spinal canal, spinal cord, and any compressive lesion, the study proved valuable in the decision as to whether surgical decompression was indicated and what approach should be used. Eleven patients were found to have significant spinal cord compression, 10 of whom were treated surgically. The technique, results, and complications resulting from the study are discussed.