The Value of Provocative Facet Blocking as a Predictor of Success in Lumbar Spine Fusion

Abstract

Studies attempting to correlate facet blocking with successful relief of pain after fusion have reached unfavorable results. These studies, however, did so in a retrospective fashion, and facet blocking was not the sole criterion by which surgical candidates were chosen. The current study is the first to use facet blocking in a prospective fashion and as the definitive criterion by which patients were chosen. Ninety-one patients with chronic low back pain who responded to bracing underwent 197 facet blocks. Twenty-eight patients who had > 70% relief of their pain for >6 h on three separate occasions were surgical candidates and underwent fusion along with two others with mechanical abnormalities but negative blocks. Pre- and postoperative Prolo (Prolo DJ, Oklund SA, Butcher M: Toward uniformity in evaluating results of lumbar spine operations. A paradigm applied to posterior lumbar interbody fusions. Spine 11:601-606, 1986) outcome scores were assigned and the patients underwent self-assessment. Twenty-three of 30 patients had successful fusion. Nineteen of 23 described 90% relief, 3 patients had 50-90% partial relief, and 1 failed by self-assessment. A preoperative mean Prolo score of 3.95 (range 2-7) improved to 7.7 (range 3-10) with fusion. Provocative facet blocking can be used to successfully predict outcome in patients undergoing arthrodesis for chronic low back pain.