• How do persons with acute (shorter than a few weeks' duration) LBP generally do? The great majority do quite well. Pain resolution often occurs within a few weeks of onset.
The patient's primary care physician should reassure him or her about his prognosis. Bed rest should be limited to at most a day or two, a quick return to reasonable activities should be encouraged (including work with short-term restrictions, if necessary), and short-term symptomatic treatments may be used (eg, low-dose NSAIDs, superficial heat, and short-term care provided by a physical therapist or chiropractor). The old days of best rest, extended time off work, and use of narcotic analgesics and muscle relaxants should be long gone. This approach is not supported by the evidence base as beneficial and it probably is detrimental (especially pertaining to return to work).
• What if the patient is just not getting better over a few weeks or the pain is severe/incapacitating? The primary care physician should conduct a focused history and physical examination and look closely for signs of radiculopathy, spinal stenosis, and underlying pathology (the "red flags" of neurological compression, infection, tumor, and trauma). If suspicion is high that something bad might be going on, lumbar x-ray films should be ordered. If the above are detected, referral to a spine surgeon makes sense. If not, patience, persistence, reassurance, and continued symptomatic interventions are key. Most patients improve within 6 weeks; if the patient does not, referral should be considered.
• After referral, MRI often is ordered. What MRI findings are important? The aim with MRI is to rule out significant neurological compression caused by disk herniation, spinal stenosis, instability, underlying infection, tumor, and trauma, not to rule in degenerative disease. Disk degeneration (loss of height, loss of fluid signal, contained bulging) and facet joint degenerative disease are normal parts of aging—the "gray hair" of the spine—and are found in most persons older than 40 years, the majority of whom have no symptoms. How these findings are associated with LBP currently is unclear.
• What do you mean? I thought degenerative disk disease and facet joint arthritis were the source of pain in patients with persisting LBP (and no significant neurological compression or underlying pathology). As noted above, degenerative findings are the norm in asymptomatic persons—if they were a pathognomic source, shouldn't we all have persistent LBP? Accordingly, other more subtle findings on MRI have been studied (eg, annular tears and bone edema). However, these subtle findings are less common and, again, are not clearly sensitive or specific to those who have LBP compared with those who do not.
• If MRI does not provide a clear pathoanatomical source of pain in patients with LBP, what about using provocative tests? Multiple interventional diagnostic tests have been used over the years to discern the source of pain in these patients. Anesthetic/corticosteroid blocks of the lumbar facet joints and diskography remain popular. However, these tests are not especially sensitive or specific; reliance on these techniques to define the "pain generator" may be misguided, and the results do not appear to correlate with eventual outcomes.
Therefore, the diagnostic summary of persisting LBP is this: The pain appears to be associated with degenerative changes in the lumbar spine, but it is unclear what the specific pathoanatomical pain source is. To date, MRI and provocative tests have not been able to differentiate patients in whom pain will persist from those in whom it will resolve as expected or from those who are asymptomatic. Indeed, the strongest correlations to persistence of pain are not found in these studies but rather in a history of psychological distress, chronic pain elsewhere in the body, or occupational/legal problems—the "yellow flags" of LBP.
• What about treatment? Assume I send the red flag patients to spinal surgeons and the yellow flag patients for psychosocial counseling. This still leaves a fair amount of patients who have degenerative changes in their backs and persisting LBP. I let them know that I do not see anything terrible on their MRI scan, but what do I do to help them get better? The evidence base is large and continues to grow. Consider the following:
NSAIDs. Based on more than 40 RCTs, NSAIDs appear to have moderate effectiveness for short-term symptomatic treatment of patients with acute LBP. Patients with chronic, persisting LBP appear to have a much smaller response that often is minimally detectable. This finding, coupled with the well-documented risks of the long-term complications of NSAID use, suggests that they should be used cautiously, if at all.
Muscle relaxants. Despite their widespread use for chronic LBP, only a handful of placebo-controlled RCTs have been undertaken. Muscle relaxants have shown a statistically significant but clinically marginal effect in reducing pain.