Patients' response to facet joint injection.

The aim of the present study was to assess prospectively patients' response to facet joint injection performed for lumbar back pain, and to check if it correlates with the response predicted by the Helbig and Lee scoring system. Fifty-seven patients who had facet joint injections for mechanical low back pain unresponsive to medical treatment, were followed-up. Patients' perception of improvement following the procedure was recorded: complete relief, partial relief, no change, worse. This response was compared with the response predicted by the Helbig and Lee score. Fifty-one patients out of 57 were available for follow-up. At the first follow-up visit (after 8 weeks) 27 (53%) of the patients claimed relief (complete relief: 15 or 29%, partial relief: 12 or 24%), no relief: 23 or 45%, worse: 1 or 2%. Surprisingly, at the second follow-up visit (after 6 months) 35 (68%) of the patients reported improvement (complete relief: 16 or 31%, partial relief: 19 or 37%), no relief: 16 or 31%. Patients with low Helbig and Lee scores were as likely to improve as those with high scores: the response to the infiltration did not correlate with the predicted response. Spontaneous improvement due to the natural history of back pain, may explain the late results. It is difficult to predict which patients will benefit from facet joint injections.