to the editor: I read with interest the article by Dr. Kinkade on the evaluation and treatment of acute low back pain in the April 15, 2007, issue of American Family Physician.¹ The article did an excellent job of reminding us of the small subgroup of “red flag” patients who have serious or life-threatening disease.¹ However, I think he missed the opportunity to identify the large and growing body of evidence regarding the sizeable subgroup of “green flag” patients who benefit from mechanical diagnosis and treatment.

More than 25 years ago, Dr. James Cyriax from Great Britain taught me that many patients could benefit from spinal manipulation, which could help get disks back into place and take pressure off the dura of the nerve roots. I then learned about the physical therapy approaches of Robin McKenzie from New Zealand, called the McKenzie Method of Mechanical Diagnosis and Therapy (MDT). A large number of physical therapists in this country know about his techniques, which begin with an initial patient assessment to reliably identify characteristic patterns of the underlying pain source. Most patients have pain that centralizes or is abolished with a single direction of lumbar exercises—i.e., they have a directional preference—which leads to patient-specific treatments. Many patients experience prompt pain relief with extension maneuvers and exercises, which decrease or eliminate the need for analgesics or nonsteroidal anti-inflammatory drugs.

Four randomized controlled trials^2–5 have documented the effectiveness of MDT in this subgroup, but guidelines fail to cite these trials or the many supportive cohort studies. I think the absence of subgroup analysis in most randomized controlled trials accounts for Dr. Kinkade's conclusion that the McKenzie method is not superior to usual therapy. The book, “Rapidly Reversible Low Back Pain: An Evidence-Based Pathway to Widespread Recoveries and Savings,” by orthopedic surgeon Ronald Donelson, MD, MS, provides an excellent summary of this evidence of benefit from MDT.⁶

There is now sufficient evidence that we can reliably identify, validate, and effectively treat certain patients with low back pain rather than continuing to address most of these patients as having a nonspecific problem with one-size-fits-all treatments.

in reply: I agree with Dr. Ajluni that spinal manipulative therapy for acute low back pain is a heavily debated topic. The difference between Dr. Ajluni's statement that manipulation produced “equivalent benefits” to usual care and the statement in my article that manipulation does not show benefit when compared with usual care is only semantic. In trials comparing spinal manipulation with sham or ineffective therapies, spinal manipulation usually shows superiority. In trials comparing spinal manipulation with usual care, manipulation usually has similar results. Although my review article did not focus on costs, several trials that show equivalent outcomes between usual care and manipulation also provide economic analysis. In these trials, manipulation typically costs more than usual care.^1–3

Of the three trials reviewed in the article by Licciardone⁴, one includes only chronic pain patients, one is a high quality trial of subacute/chronic back pain (three weeks to six months) that shows equivalence to usual care, and one is a low quality trial of mixed acute and chronic patients that showed equivalence to sham treatment.

I thank Dr. Kollisch for describing the McKenzie method of therapy for back pain. It may very well be helpful to a subgroup of patients. Trials in patients with acute low back pain are lacking. Two of the trials mentioned by Dr. Kollisch involved patients with chronic back pain (mean duration two to four months).^5,6 The study by Schenk and colleagues is a small, low-quality trial of patients with back pain ranging from seven days to seven weeks. It was included in both of the systematic reviews I cited. Although the study by Brennan and associates enrolled patients with acute back pain (less than 90 days, but median duration about two weeks), it did not show a benefit for patients assigned to receive McKenzie therapy.⁷