The researchers (NEJM 2013;38:999-1007) report on a study of 283 patients from the Netherlands who had suffered with 6 to 12 weeks of sciatica and had a confirmed disc herniation on MRI. Patients either received early disc surgery or “prolonged conservative care” (such as medications and physical therapy). After one year, all participants underwent a follow up MRI and were questioned about their recovery. 84% of study participants reported a favorable outcome (hey, that’s pretty good). But, interestingly, their MRIs looked terrible. In fact, 85% of this group (this is the group with favorable outcome) had evidence of ongoing disc herniation and nerve root compression on their MRI, regardless of which treatment they received, surgery or conservative care.
Even more stunning were the participants with favorable outcomes whose MRIs showed evidence of scar tissue wrapped around the nerve where the surgery was performed. Of the 170 patients who underwent surgery, 88% had visible scar tissue on MRI and of these, 96% had scar tissue surrounding the nerve root, and yet 86% reported favorable outcomes. This compares to only 75% reporting favorable outcomes in the surgical group without evidence of scar tissue formation. Huh?
Of course, this is far from the first study to show the lack of correlation of MRI findings with patients’ symptoms. A seminal study by Jensen in 1994 showed that if you evaluate 100 individuals who have no pain or other symptoms with an MRI of their lower back, only 36% of those had normal MRIs. The rest (the other 63% of those with no pain) had disc bulges and protrusions (Jensen, NEJM 1994;331:69-73).
When physicians evaluate patients who have had poor outcomes after disc surgery or who have back pain and sciatica to begin with, they often look to the MRI for an explanation of symptoms or for lack of improvement. After surgery, scar tissue around a nerve root, in particular, is often used to explain ongoing pain. This study strongly suggests that this finding could be completely unrelated to the pain. Of course, then the question is; how do we discover the cause? I believe the answer lies in the physical examination, a nearly lost art in medicine these days.
As healthcare professionals, we have become overly reliant on technology, in general, losing touch with the finely honed physical exam skills that our predecessors relied on exclusively. Many patients with back pain and sciatica get treatment recommendations for conservative care, injections or surgery based completely on their MRI findings. So-called “abnormal” findings on MRI are thought to validate their pain. Meanwhile patients with relatively normal MRIs, are often told that there is “nothing wrong”, the suggestion being that their pain is wholly psychological. Patients lose in both scenarios. What is really needed is a careful musculoskeletal and neurological examination to uncover the root source of pain. I believe the answer is often there, if we are only willing to look.