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Cervical spine injury patients require careful evaluation to prevent further morbidity due to apparent and hidden injuries. Systematic evaluation including injury history, physical examination, and imaging studies helps to prevent complications from missed injuries. Awake and alert patients who have negative exam findings do not require further evaluation. When utilized appropriately, cervical spine evaluation algorithms have decreased the morbidity for injured patients.1–3

Cervical collars should be removed as soon as feasible after trauma. As soon as an injury has been excluded, the collar should be discontinued to decrease collar-associated morbidity. Some examples of morbidity associated with collar use are decubitus ulceration^4–6 and increased intracranial pressure (ICP).^7,8 Increased duration of mechanical ventilation, longer intensive care unit (ICU) and hospital stays, and increased incidence of delirium and pneumonia were also associated with collar use.⁹

Radiographic evaluation with plain x-rays, dynamic x-rays, computed tomography, and magnetic resonance imaging (MRI) in a systematic manner minimizes the chance for undetected occult injury. In turn, this decreases additional patient morbidity. The end point in evaluation of these injuries is the detection or exclusion of significant injury to the cervical spine. MRI has been especially touted for the ability to detect ligament and disk injury in the face of normal radiographic and CT studies. Significant injury is that which requires ongoing treatment, either with immobilization or with surgery. Clearing the cervical spine of injury is a critical phase in the treatment of polytrauma patients to further the treatment process and prevent morbidity associated with immobilization.¹⁰ Clearance is best defined as the exclusion of significant injury, and this allows discontinuation of immobilization and precautions, better pulmonary care, and easier ancillary care.

In the past, practice guidelines based on clinical experience have led to better detection rates of injury and hence improved patient care. The development of evaluation protocols based on best evidence medicine and the increased access to advanced imaging studies (especially CT) has paralleled the improvement in patient care.¹ In general, CT has become a frontline tool in the evaluation of blunt trauma and cervical spine injury, often supplanting the need for plain radiographs.¹¹

A comprehensive review of the literature included a search of the Medline database and a review of the references of relevant review articles. The best evidence for the use of advanced radiographic imaging studies for evaluation of cervical spine injuries was chosen from the search (Table 2.1). For evaluation of MRI in clearance of the cervical spine, three level I studies were identified and one meta-analysis. Three level II studies of the use of MRI were also identified. Two level III studies comparing dynamic x-ray versus CT where identified: one relying on upright (gravity added) x-ray and the other manual flexion and extension range of motion x-rays. Lastly, the efficacy of CT to detect the extent of injury is well described in multiple level III retrospective comparative studies versus both plain x-ray and MRI.

Table 2.1 Evidence of Published Studies

Benzel et al12 reported on 174 patients of whom 62 were found to have abnormal findings on MRI. Two of those patients underwent operative stabilization treatment, and the others were treated with cervical orthoses. All of these patients had stable flexion-extension radiographs at 1 to 3 months follow-up. The negative MRI patients had their prophylactic cervical immobilization discontinued after the negative scan. No complications were noted in the cohort at final follow-up. The negative predictive value (NPV) for MRI was 100%, and there were no false-negatives.

Schuster et al¹³ reported on 120 patients who were obtunded but without apparent clinical neurological injury. All patients had a normal x-ray or CT scan and persistent neck pain or significant mechanism for injury. Fifteen patients were treated in a cervical collar for soft tissue injury noted on their MRI scan, and the remaining 105 patients with normal MRI scans had their cervical collar removed. Final follow-up revealed no complications. Again, the NPV was 100%, and there were no false-negatives.

Muchow at al¹⁴ performed a meta-analysis in studies all with greater than 30 patients. Inclusion and exclusion criteria were homogeneous, and imaging (MRI) studies were performed within 72 hours in three studies, in less than 48 hours in two studies, and within 24 hours in the final study. Overall, a normal MRI had an NPV of 100%, allowing discontinuation of immobilization in a timely manner.

Level II Studies

Albrecht et al¹⁵ described a retrospective study of 48 patients who were obtunded and underwent MRI after a negative x-ray and/or CT scan. A positive MRI was found in 27 patients. Twenty-one patients had a normal MRI scan and went on without complications. No false-negatives and an NPV of 100% were reported. However, poor follow-up (41%) was a deficiency of this study.

D’Alise et al¹⁶ reported on 121 intubated patients who had cervical injury risk factors and a normal CT scan. Patients were excluded if they had abnormal x-ray findings, a CT abnormality, or evidence of neurological injury. Thirty-one patients had abnormal MRI scans, and eight underwent surgical stabilization; 23 others were lost to follow-up. Ninety patients had normal MRI scans, and the collar was removed. In addition, flexion and extension x-rays in these 90 patients were also normal. No false-negatives were found, and the NPV for MRI was 100%.

Keiper et al¹⁷ treated 52 patients for whom MRI was obtained after CT disclosed no abnormality and question of injury remained. The MRI scan was abnormal in 16 patients, and four underwent operation; the others were treated with an orthosis. For those 36 patients with normal MRI, the collar was discontinued, and follow-up revealed no abnormalities. Again, there were no false-negatives, and the NPV was 100%.

Como at al¹⁸ reported a prospective evaluation of 115 obtunded patients with a negative CT scan for acute cervical trauma in whom MRI of the cervical spine was subsequently obtained. Six injuries were identified on MRI, but no management changes occurred. Complications from cervical collar use in six patients occurred, but no complications due to transport or image acquisition occurred. Significant cost savings by eliminating the cervical spine MRI were estimated at $250,000. The authors concluded that for patients with negative cervical spine CT, MRI did not affect the treatment plan and may be unnecessary.

Platzer et al¹⁹ reported diagnostic criteria for the use of MRI to avoid a delay in diagnosis. Prospective patient evaluation was retrospectively analyzed for 118 patients. CT was most efficient in detecting skeletal injuries with a sensitivity of 100%. MRI was necessary to detect significant ligament injuries in 6% of patients.

Level III Studies

Holmes et al²⁰ confirmed that MRI is superior at identifying spinal cord injury (SCI) and ligamentous injury and CT was better at significant bone injury detection.

Hogan et al²¹ described a group of patients for whom a follow-up MRI scan was negative, which correlated with an initial negative CT scan.

Stassen et al²² described a high percentage of obtunded patients (25%) with ligamentous injuries detected by MRI, but none required treatment beyond immobilization.

Sarani et al²³ described a group of 46 obtunded patients with a normal CT scan of whom five had abnormal MRI results (four ligamentous and one herniated nucleus pulposis [HNP]); with the four ligamentous injuries treated with an orthosis for 6 weeks.

In patients with negative MRI findings for whom previous studies were inconclusive or negative for osseous injury, Horn et al²⁴ recommended clearance of the cervical spine.

Computed Tomography

Schenarts et al25 prospectively compared CT to plain x-ray in 1356 patients with altered mental status. In 70 patients, 95 injuries to the upper cervical spine were identified. Plain radiographs failed to identify 45% of the cervical spine injuries.

Level II Studies

A retrospective cohort study was reported by Harris et al²⁶ to determine the frequency of injuries missed by initial CT of the cervical spine in 367 obtunded blunt trauma patients. The CT scan had an NPV of 99.7%. Only one patient out of 367 patients was eventually found to have an initially undetected injury through additional imaging. This patient had a cervical spinal cord contusion associated with posterior ligament injury and underwent no further treatment. In this study, the addition of an upright cervical spine radiograph used to test dynamic stability did not identify any further injuries. The only additional injury identified was found by clinical examination with impaired sensorimotor function with a confirmatory MRI scan, which revealed a posterior ligament injury and spinal cord contusion. The delay to obtain an upright cervical spine radiograph in the obtunded patient was 2.6 days after the initial CT scan.

Cooper and Ackland³ performed a retrospective review at Alfred Hospital in Melbourne, Australia, demonstrating the superiority of CT imaging alone over plain x-rays, adjunctive dynamic flexion-extension x-rays, and MRI scanning in their trauma population. They reported that up to 16% of cervical spine injuries were missed by plain x-rays alone, which is similar to other reports in the literature.^3,11,19 There were no additional unstable injuries identified when dynamic flexion-extension x-rays were utilized when compared with injuries identified with helical CT reconstructions. Based on logistic concerns, such as complex transport requirements and image acquisition time, there were no advantages of MRI in detecting cervical disk and ligamentous injuries.

Dynamic Plain X-rays

Level I Studies

There are no level I studies available.

Level II Studies

There are no level II studies available.

Level III Studies

In another study from the Alfred Hospital, Padayachee et al²⁷ studied the optimal protocol for clearing the cervical spine in unconscious patients with traumatic brain injury. The study included 276 unconscious patients who underwent plain x-ray, CT scanning with three-dimensional (3-D) reconstructions, and dynamic flexion-extension x-rays with fluoroscopy. Radiographic reports from a prospective ICU database were reviewed and were the focus of this study. The dynamic flexion-extension x-rays performed with fluoroscopy identified no new fractures or instability. False-negative results occurred in one patient on flexion-extension views, and false-positive results occurred in six patients. Dynamic flexion-extension x-rays were inadequate in nine patients. No injuries were identified as a consequence of performing dynamic flexion-extension x-rays.

Spiteri et al²⁸ found no advantage of dynamic cervical screening to helical CT in spinal clearance, and due to its redundancy, have abandoned its routine use.

Platzer et al¹⁹ presented a comprehensive cervical spine imaging protocol to avoid unnecessary delays in the diagnosis of cervical injury. A spiral CT scan showed a sensitivity of 100% for detection of skeletal injury while a single cross-table lateral view x-ray achieved only a 63% sensitivity. Functional radiography and an MRI scan detected a significant ligamentous injury in 6% of patients. By utilizing their CT scan protocol, a delay in diagnosis was avoided.

Additionally, Anglen et al²⁹ reported that, although flexion-extension x-rays are commonly inadequate, when properly performed, they have a high NPV. Griffiths et al³⁰ reported that 59% of flexion-extension studies were inadequate and that this, combined with a lack of cost-effectiveness, was the reason that use of this screening exam was discontinued for obtunded trauma patients. Bolinger et al³¹ concluded that bedside flexion-extension radiographs should no longer be utilized in the clearance of comatose patients due to the high number of inadequate studies. Insko et al³² reported 30% of flexion-extension radiographs inadequate, but when no limits to range of motion (ROM) on physical exam were present, the false-negative rate was zero. Strict adherence to fluoroscopy protocol must be followed because Davis et al³³ reported the complication of quadriplegia in one patient for whom a strict protocol was violated.

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