Facet joint injection did not relieve chronic low-back pain
ACP J Club. 1992 Jan-Feb;116:14. doi:10.7326/ACPJC-1992-116-1-014
Carette S, Marcoux S, Truchon R, et al. A controlled trial of corticosteroid injections into facet joints for chronic low back pain. N Engl J Med. 1991 Oct 3;325:1002-7.
To evaluate treatment of chronic low-back pain with methylprednisolone injection into facet joints.
Randomized, double-blind, placebo-controlled trial with 6 months follow-up.
Rheumatology outpatient clinic.
190 consecutive patients with low-back pain for > 6 months were given a lidocaine injection in the lower 2 lumbar facet joints to identify those who had pain originating in or near the facet joints. 110 patients reported a > 50% pain reduction, and 101 of these were entered into the study. Patients' mean age was 43 years; 54% were men. Follow-up was 93%, and analysis was according to intention-to-treat.
Patients were injected with isotonic saline or 20 mg of methylprednisolone acetate in the same facet joints as in their prestudy assessment.
Main outcome measures
Patients rated overall effect on a 7-point scale, and pain on a visual-analog scale and using the McGill Pain Questionnaire. Functional status was evaluated using the Sickness Impact Profile, and back flexion was evaluated by measuring the distance from fingers to floor on maximal forward flexion. The study had 80% power to detect improvement in 50% of study group patients compared with improvement in 25% of the control group (5% level of significance).
At 1 and 3 months after injection, none of the outcome measures differed between the groups. At 1 month, 20 (42%) study group patients and 16 (33%) control group patients reported marked improvement. 3-month figures were similar. After adjusting for co-interventions, 15 (31%) of the methylprednisolone patients and 8 (17%) control patients experienced marked improvement after 6 months (95% CI -3 to 31, P = 0.17). The study group, although similar to the control group, reported slight trends to less pain, reduced physical disability, and greater flexion after 6 months. Few patients reported sustained improvement. For the 20 study patients reporting improvement at 1 month, only 11 (55%) were still improved at 6 months. For control patients only 5 of 16 (31%) sustained their 1-month improvement at 6 months. Neither group reported adverse effects.
The injection of methylprednisolone into facet joints was not effective in relieving chronic back pain.
Sources of funding: Medical Research Council of Canada and the Canadian Life and Health Insurance Association.
Address for article reprint: Dr. S. Carrette, Centre Hospitalier de l'Université Laval, 2705 Boulevard Laurier, Sainte-Foy, Quebec G1V 4G2, Canada.
Even though low-back pain is an extraordinarily prevalent and disabling condition, few randomized trials have been performed to assess the value of common treatments. A randomized trial of bed rest was not reported until 1986 (1). It showed no benefit from more than 2 days of bed rest among patients with normal neurologic examinations, and patients assigned to lengthier bed rest had more days of disability. Lumbar disc surgery became a standard of care after publication of Mixter and Barr's case series in 1934, but randomized trials of its efficacy have yet to be done (2). More recently, discography has been advocated in patients with 4 months of back pain and unrevealing standard tests (3). Randomized trials need to be done to determine whether discography and lumbar surgery actually benefit patients.
The popularity of facet joint injections represents an effort to improve treatment of a difficult health problem. On the other hand, this treatment symbolizes the overly mechanistic approach that has dominated back pain management since Mixter and Barr. Patients with chronic back pain suffer from a complex psychophysiologic process that requires a multifaceted treatment approach. Passivity on the part of the patient is a poor prognostic sign, and technologic fixes given by the doctor may inadvertently reinforce passivity. This study shows that facet joint injections are not a magic bullet. Practicing physicians and researchers need to focus more on nontechnologic interventions such as exercise, psychologic evaluation and treatment, and use of structured return-to-work programs.
Linda M. Frazier, MD
Duke UniversityDurham, North Carolina, USA