Study: “Red Flags” Not Reliable for Spinal Pathologies

A group of Finnish researchers have dug into the issue of how surgeons determine if low back pain is actually a serious spinal condition.

Their study, “Specific spinal pathologies in adult patients with an acute or subacute atraumatic low back pain in the emergency department,” was published in the December 2018 edition of International Orthopaedics.  

Co-author Aleksi Reito, M.D., Ph.D. with the Department of Orthopedic Surgery and Traumatology at Central Finland Hospital in Jyväskylä, explained the purpose and objective of his study to OTW, “Low back pain (LBP) is very common reason to visit the emergency department (ED). The first step in the evaluation is to suspect or exclude serious/specific reasons owing to LBP.”

“Very often so-called red flag symptoms are recommeded to use in this process.”

“Recent studies however indicate that these red flags work very poorly. Intuitively this owes to the fact that the proportion of patients having a serious or specific reason is extremely low and hence the accuracy is poor. There is however no single study in which the incidences of these reasons, namely cauda equina syndrome, infection, fracture and cancer among patients presenting in the emergency department would have been investigated.”

Using their institutional database, the authors identified 900 patient visits where the diagnosis was atraumatic low back pain. They write, “Of these 284 (31.6%) were due to nonspecific LBP, and 583 (64.8%) were due to radicular pain suggesting nerve root compression. In 33 (3.7%) cases, the LBP was caused by a specific spinal pathology.”

Dr. Reito told OTW, “The incidences of the serious reason for back pain were, as expected, very low, especially cancer and cauda equina syndrome. Clinicians working in the emergency department and assessing patients with LBP should not trust too much on red flags since they occur infrequently.”

“Instead each patient should be considered individually and we recommend low threshold for referral and imaging if there is any suspicion of serious cause for LBP. Nowdays, modern imaging modalities are readily and better available than earlier and therefore we should tolerate a higher rate of wrong positives in order to avoid wrong negatives, since these may have devastating outcomes on the individual level.”

“Since red flags do not work as they should due to the low prior probability of serious disease the community should work to find better tools predicting those with serious cause for back pain.”