RESUMO
OBJECTIVE: To investigate the efficacy, safety and tolerability of paraspinal administration of botulinum neurotoxin type A (BoNT-A) in patients with chronic low back ache (LBA). SUBJECTS AND METHODS: Eight patients with chronic LBA were injected with BoNT-A at three sites on either side of lumbar paraspinal muscles. The patients rated their pain intensity using a visual analogue scale (VAS) from 0 to 10, and our physiotherapist assessed the paraspinal muscle spasm using a functional scale (FS) from 0 to 5. The improvement in both VAS and FS 30, 60 and 90 days after BoNT-A from baseline was analyzed separately using paired t test. The correlation between the muscle spasm (FS) and pain relief (VAS) was analyzed using the Spearman's rank correlation coefficient test. The level of statistical significance was p < 0.05. RESULTS: Five (63%) patients showed a remarkable recovery in VAS and FS, whereas 2 (25%) patients showed improvement only in FS. Statistically significant improvement was achieved in VAS and FS independently 30 days (p < 0.02 and p < 0.02, respectively), 60 days (p < 0.01 and p < 0.001, respectively) and 90 days (p < 0.02 and p < 0.001, respectively) after treatment. Pain relief started early and it was independent of relief of muscle spasm 30 days after treatment (r = 0.685; p > 0.05). CONCLUSION: With this limited study, we have demonstrated that the paraspinal injection of BoNT-A is effective in relieving chronic LBA without producing side effects. The injection is an easy procedure, well tolerated and did not require anesthesia or imaging technique.
