Day after day, I get a patient coming in stating they have “degenerative and bulging discs” per MD. Physical therapists are fortunate that we don’t deal with life-threatening diseases on a daily basis but I feel these two words are the most debilitating that I hear. I really don’t like these two words for a few reasons. First, ‘degeneration and bulging disc’ have such a high psychosocial role. They are very despairing and create such a negative vibe to the patient. Many feel they will always have pain and have done something wrong their whole life leading to the deterioration.
Should we re-phrase the terms and classify their pain differently for the sake of the patient? Can we do this?
MRI is a great tool and has been shown to be over 90% in specificity, sensitive and accurate in most classifications of lumbar disc herniations. However, the usefulness of this precision is not shown to be greatly meaningful to clinical physical therapy practice. The reason is due to the high number of false positives on asymptomatics shown on MRI. This is found in multiple studies over the years:
20% of asymptomatics < 60 y/o had disc herniation.
51% of asymptomatics 40-59 y/o had incidence of lumbar disc degeneration
-Boos et al 1995:
76% of asymptomatic, high-risk subjects had at least one disc herniation.
85% of asymptomatics had confirmed disc degeneration involved one at least one level
–49-63% of asymptomatics in 1500 Boston Hospital Employees showed disc herniation.
So, if disc herniation isn’t the cause of the pain, then what is? Many theories exist from referral patterns within the disc (such as pain to shoulder/arm in heart attack) to biochemical factors (chemical components may sensitize the nerve roots resulting in pain). Other structures include the zygopophyseal joint, capsules, outer layers of the annulus and ligaments. However, for the scope of this post, I am going to talk about the lumbar multifidi. Yes, the muscle.
Kader (2000) examined the relationship between lumbar multifidus (LM) muscle atrophy and low back pain, leg pain and intervertebral disc degeneration.
In a retrospective study of 78 patients, they found the following:
–80% of patients with LBP showed LM atrophy
–L5/S1 was the most frequent level of atrophy even though it was found mainly at L4/5 and L5/S1
-Pearson’s correlation between LM atrophy and leg pain was found to be significant (p<0.01)
-~50% of patients with root pain (18 of 38) and leg pain (25 of 57) only had LM atrophy and not herniated nucleus pulposus, spinal stenosis or nerve root compression
So, what does all this mean? Basically, it is not a cause and effect relationship entirely, but the more LM atrophy = more leg pain. The authors concluded that in the LM atrophy may explain leg pain in the absence of other MRI abnormalities. Can we improve this by strengthening the LM?
Did the atrophy lead to leg pain or pain lead to atrophy? I would suggest the latter but it is still unknown currently. Doesn’t that correlate with other studies involving the TrA?
So, should we correct our patients in explaining the cause of their pain based on the current research? How about if we refer to their pain as “referred pain”, rather “radiculopathy” from a bulging disc. Because really, do we know?
Boden SD et al. “Abnormal magnetic resonance scans of the lumbar spine in asymptomatic subjects: A prospective investigation.” J Bone Joint Surg Am 1990; 72A:403-408
Boos N, et al. “1995 Volvo Award in clinical science: The diagnostic accuracy of MRI, work perception, and psychosocial factors in identifying symptomatic disc herniations.” Spine – 1995; 20:2613-2625
Kader, D., Wardlaw, D., Smith F. (2000). Correlation between the MRI changes in the lumbar multifidus muscles and leg pain. Clinical Radiology, 55, 145-149.