Session VI - Pediatrics

The Value of Prevertebral Soft Tissue Swelling in Identifying Pediatric Cervical Spine Trauma

Lisa K. Cannada, MD; Daniel R. Cooperman, MD; John A. Davis, MD; William F. Fallon, MD; Charles Thomas, MS, MetroHealth Medical Center, Cleveland, OH

Purpose: In the standard radiograph of the lateral cervical spine, widening of the retropharyngeal soft tissue space is often associated with cervical spine trauma. Does the absence of swelling correlate with the absence of cervical spine injury? The purpose of our study was to determine the value of retropharyngeal soft tissue swelling as a measure of spine injury in a population of patients 18 years of age and under with known cervical spine injury.

Methods: We reviewed our Trauma Registry for a population of 50 consecutive cervical spine injuries in patients 18 years of age and younger; there were 27 boys and 23 girls with an average age of 14 years (range, 1 to 18). The average Injury Severity Score was 21 (range, 3 to 75). Thirty-seven injuries were classified as anterior and thirteen injuries were posterior. The majority of fractures were at the C2 level (n = 18) and at the C5-7 level (n = 23). Data collected included age, gender, and Injury Severity Score. The fractures were classified according to the OTA classification. In addition, the fractures were divided into anterior-column injuries involving the body or pedicle and posterior-column injuries involving the transverse process, lamina, or spinous process and respective ligamentous structures. Injuries involving both portions were classified as anterior injuries. The prevertebral soft tissue swelling was recorded at C2 and C6 by measuring from the most anterior inferior border of the vertebral body to the most posterior border of the airway shadow. The cutoff values were 6 mm of prevertebral soft tissue swelling at C2 and 22 mm of swelling at C6. Single measurements were recorded at each level. All measurements were take from the initial injury radiograph of the lateral cervical spine. Statistical analysis was completed to calculate the mean and standard deviation of measurements and to determine sensitivity and false negative values at the levels measured.

Results: The mean prevertebral soft tissue shadow at C2 was 8.7 mm, with a standard deviation of 6.0 mm. At C6, the mean prevertebral soft tissue shadow was 12.9 mm, with a standard deviation of 4.3 mm. A C2 prevertebral soft tissue measurement of more than 6 mm had a sensitivity of 59%. A C6 measurement of more than 22 mm had an overall sensitivity of only 1%. Our overall rate of false negatives at C2 was 41% and at C6 was 99%. There was no significant difference between anterior and posterior injuries for soft tissue swelling and detection of injury (P = 0.238 and 0.514 respectively).

Discussion: Patients with multiple trauma are at risk for missed cervical spine injuries. Many have altered levels of consciousness and/or distracting injuries that make physical examination difficult. Under these circumstances, screening radiographs take on great value. Retropharyngeal soft tissue swelling is thought to correlate with cervical spine injury. In our series, the false negative rate for a single lateral cervical spine radiograph using standard accepted criteria at C2 was 41% and at C6 was 99%. Therefore, we believe the absence of soft tissue swelling on a lateral cervical spine x-ray is not a good screening tool for the detection of occult cervical spine injury.