Injection therapy for enthesopathies causing axial spine pain and the "failed back syndrome": a single blinded, randomized and cross-over study.

Background: Enthesopathies are a common cause of axial pain that is amenable to "minimally invasive" therapy.

Objective: To evaluate the effectiveness of injection therapy for enthesopathies.

Design: Single blinded, randomized, and cross-over study.

Methods: Thirty-five patients diagnosed as having painful enthesopathies as a major pain generator were studied. Of the patients studied, 86% of patients had undergone prior lumbar spine surgery and all were referred for neurosurgical evaluation for possible surgery. Patients were injected either with anesthetics alone or with anesthetics combined with phenol-glycerol proliferant prolotherapy. Outcomes were analyzed both clinically at the time of regular follow-ups, and by a series of multipart questionnaires.

Results: Patients received a total of 86 injections, 39 with local anesthetics, and 47 with prolotherapy. By clinical assessment patients obtained excellent to good relief of pain and tenderness after 80% of prolotherapy injections, but only 47% after anesthetics alone. By questionnaire, 66% reported excellent to good relief after prolotherapy vs. 34% after anesthetics alone. Patients reported improvement in work capacity and social functioning following both types of injections, but a greater reduction in focal pain intensity following prolotherapy injections. The mean and median durations of persistent relief were 2.4 and 1.75 months with prolotherapy vs. 1.8 and 0.75 months with anesthetics alone. Roughly 10% obtained greater than six months of relief from either injection. In the crossover portion of the study, patients reported that prolotherapy injections following initial anesthetic-only injections provided much better relief than that achieved after their anesthetic-only injections, and that anesthetic-only injections following initial prolotherapy injections failed to provide relief as good as that achieved after their prolotherapy. Subsequent to this study, only four of 35 patients required additional spine surgery, but 29 of the 35 patients requested additional injections.

Conclusions: Injection therapy of painful enthesopathies can provide significant relief of axial pain and tenderness combined with functional improvement, even in "failed back syndrome" patients. Phenol-glycerol prolotherapy provides better and longer lasting relief than injection with anesthetics alone. Prolotherapy provides over six months of relief for some patients but generally provides relief for only a few months. However, most patients described good to excellent relief, felt that the injections had been beneficial, and requested additional injections for recurrent or residual focal pain.