In the second post of the “Low Back Pain and You” series, I would like to discuss the use of imaging and the role it plays in the diagnosis and treatment of low back pain. As I’ve discussed, imaging is often a part of the normal course of low back pain. Primary care physicians and orthopaedic specialists are eager to order at least a radiograph (x-ray), yet rarely discuss the problems with their interpretation in terms of low back pain.
The fact of the matter is that medical imaging is overutilized and means little in most cases of low back pain. In fact, their findings or interpretation usually fail to correlate with clinical signs and symptoms. For example, an x-ray may show “no or mild degenerative changes” yet the patient have severe back pain. Conversely, the x-ray may show a tremendous amount of degeneration in a patient with not a single complaint.
Why is this the case? In many cases, the exact pathoanatomical cause of one’s LBP cannot be determined by any method. Of course there are exceptions, acute trauma with fracture or a large herniated disc with clear nerve compression or cord changes are most likely the cause if present.
How about magnetic resonance imaging or MRI? MRI’s are more advanced (and more expensive) imaging devices that give a more complete picture of the soft tissues (muscles, ligaments, tendons, etc) of the body. In many cases of LBP, the MRI is ordered to examine the intervertebral discs. While the advanced technology is nice and has improved identification of many pathologies and injuries (i.e. knee ligament ruptures, torn rotator cuffs, etc), they often lead to a false sense of knowledge in the case of LBP. False positives have been reported in up to 30% of MRI cases.
So, why are imaging studies ordered so consistently? Tradition and defensive medicine. For years, the standard protocol has been to order an x-ray and/or MRI with the rationale that it’s better to be safe than sorry. I would agree that safety (i.e. not missing a serious pathology) is vital. I would like to also inform the public that medical literature has shown that Physical Therapists can screen these pathologies out or refer to appropriate practitioners without the expensive overutilization of imaging.
I certainly believe that imaging is both indicated and of value in certain cases, but not for every incidence of LBP. The recent practice guidelines published by the American College of Physicians and the American Pain Society have taken one step to address this issue. They recommend imaging studies only be conducted in patients when severe or progressive neurological conditions are present or suspected. I hope the physicians are listening.