IS AGE LESS THAN 20 A USEFUL “RED FLAG” SIGN IN LBP?

Abstract

Background: Guidelines for the management of Low Back Pain (LBP) consistently recommend that initial assessment should focus on the detection of serious spinal pathologies. In 1994 the UK Clinical Standards Advisory Group introduced the concept of “red flags”. One flag is the presentation of back pain in people under the age of 20. LBP in children is common, with an annual and lifetime prevalence of around 30%. Because many cases of benign and malignant spinal tumours and spinal infection have been documented in this age group, young people with LBP who are referred to secondary care are investigated by MRI.

Purpose: The purpose of this study is to review the incidence of tumour and infection in subjects under age 20, who present to secondary care with LBP, but do not have concerning objective findings such as neurology, fever, acute deformity or scoliosis.

Method/Results: A retrospective analysis of the MRI database, at a specialist orthopaedic hospital, from 1994 until 2005 identified 403 limited MRI’s taken in LBP patients under the age of 20. Analysis revealed 2 radiological reports of spinal tumour, 1 ependymoma and 1 osteoid osteoma and no cases of spinal infection. Histology confirmed pathology in the ependymoma but excluded serious pathology in the osteoid oste-oma. Other MRI findings, included minor degenerative change (17%), pars defect (9%) and disc prolapse (4%). Therefore, over an 11 year period only 0.25% of young people with LBP who underwent limited MRI were found to have serious pathology.

Conclusion: In conclusion, LBP is relatively common in people under the age of 20 and can be severe enough to warrant secondary care referral. However, in the absence of other objective findings, serious pathologies such as cancer and infection remain rare. These results support the use of limited MRI for screening. However, further research into the clinical value of “under 20” as an independent red flag is recommended.