Nerve root sleeve injections in patients with failed back surgery syndrome: A comparison of three solutions

Objective: To evaluate outcome in patients with failed back surgery syndrome treated with nerve root sleeve injections. Design and Patients: An open, nonblinded, randomized study on 60 patients with documented fibrosis in fewer than three nerve roots. Interventions: After random selection, 20 patients were injected with I mi bupivacaine 0.5% combined with 1500 units hyaluronidase and 1 mi saline per nerve root sleeve (group A), another 20 were treated with I mi bupivacaine 0.5% combined with 40 mg methylprednisolone solution (Depo Medrol) per nerve root (group B), and a third group was treated with bupivacaine 0.5% combined with 1500 units hyaluronidase and 40 mg methylprednisolone solution (group C). The volume of each injection was 2 mi. The injections were given twice at an interval of 1 week. Outcome Measures: The patients were evaluated on a verbal pain rating scale I, 3, and 6 months after the second injection. The Kruskal-Wallis test was used to detect statistically significant differences among the three groups, and the analysis was refined with the Friedman test. Results and Conclusions: Overall, although injections induced analgesia at 1 month, these effects were reduced at 3- and 6-month follow-ups. No statistical differences were found between the three treatment groups after 1 month, p = 0.71; after 3 months, p = 0.69; after 6 months, p = 0.66. The Friedman test showed a significant decrease in treatment score as a function of time in groups B and C (p = 0.015) but not in group A (p = 0.074). Corticosteroids seem responsible for the last phenomenon.