Streamlining the evaluation of low back pain in children

Abstract

The workup of low back pain in children often results in overimaging so as not to miss organic back pain. The primary goal of this study was to identify which combination of imaging modalities provides the most sensitive and specific screening protocol for children with low back pain. Medical records from 100 consecutive patients between 2 and 18 years of age presenting with low back pain, without night pain or constitutional symptoms, were evaluated. A hyperextension test combined with a radiograph showed a negative predictive value of 0.81 and sensitivity of 0.90. The addition of a bone scan was highly effective in achieving good negative predictive value and sensitivity. Bone scans had perfect negative predictive value and sensitivity when symptom duration was less than 6 weeks. We identified a set of factors that is highly predictive for distinguishing organic back pain from mechanical back pain. Painless hyperextension combined with negative anteroposterior, lateral, and oblique lumbar radiographs and magnetic resonance images predicts mechanical back pain. For patients with nonneurologic back pain of less than 6 weeks duration, bone scan is the most useful screening test because it is accurate, accessible, inexpensive, and unlikely to require sedation.

Level of evidence: Level III, diagnostic study.

Fig. 1

This diagram depicts the selection process of the final study population. ICD-9 = International Classification of Diseases, 9th Revision; SPECT = single photon emission computed tomography.

Fig. 2A–B

These figures show the time-dependent value of (A) SPECT and (B) MRI and in the diagnostic workup of back pain in children. Negative predictive values (NPVs) and sensitivities (Y-axis) are shown as a function of symptom duration (X-axis) for (A) SPECT and (B) MRI studies.

Fig. 3A–B

The graphs show the potential reduction of imaging, cost, and sedation (among 100 patients evaluated) that would have been achieved using SPECT during the first 6 weeks of symptom duration and MRI after 6 weeks of symptoms. Relative reduction in (A) imaging numbers and (B) costs and sedation numbers are shown. The blue bars represent the actual total in our study population and maroon bars represent the potential total had our study results been used as guidelines (SPECT scan for symptom duration within 6 weeks and MRI for longer duration).