Transforaminal epidural clonidine versus corticosteroid for acute lumbosacral radiculopathy due to intervertebral disc herniation

Abstract

Study Design: Randomized, double-blinded trial clinical trial.

Objective: To compare efficacies of 2 active therapies for chronic low back pain.

Summary of Background Data: Radicular pain may result from intervertebral disk herniation (IDH). Clonidine has demonstrated analgesic and antiinflammatory activity in animal studies of nerve injury. Extensive clinical experience supports neuraxial clonidine's safety.

Methods: Patients with ˜3 months of low back and leg pain due to IDH were randomized to transforaminal epidural (TFE) injection(s) of 2% lidocaine and either clonidine (200 or 400mcg) or triamcinolone (40mg). Patients received 1- 3 injections administered about 2 weeks apart. Patients, investigators and study coordinators were blinded to treatment. Primary outcome was 11-point Pain Intensity Numerical Rating Scale (PI-NRS) at 1 month. Other outcomes included Patient Global Impression of Change (PGIC), and functional measures.

Results: Thirty-three patients were screened and randomized. Twenty-six patients enrolled; 11 received clonidine and 15 triamcinolone. Both groups showed significant improvement in pain score at 2 weeks and 1 month compared to baseline (p< 0.05). The corticosteroid group showed additional functional improvement at 1 month relative to clonidine (p=0.022). There was no difference between groups for primary outcome. However, as target enrollment was not reached, we cannot say with confidence that the 2 treatments would be expected to result in similar short-term pain relief. Side-effects were common in both groups, but there were no serious complications.

Conclusions: Radicular pain due to IDH improved rapidly with TFE injection of either clonidine or triamcinolone. Corticosteroid resulted in greater functional improvement, with unclear differences in analgesia. Future studies will determine if clonidine is superior to placebo and of particular use in those at risk for corticosteroid complications.

Figures

Figure 1

Antero-posterior radiographic view of needle in final position within the target neuroforamen. Radiographic contrast is seen along the nerve root and in the epidural space at the target vertebral segment.

Figure 2

Lateral radiographic view of needle in final position within the target neuroforamen. Radiographic contrast is seen in the anterior epidural space, in close proximity to the putative site of nerve injury.

Figure 3

Patient flow chart demonstrating enrollment, randomization and follow-up periods.

Figure 4

Mean ±SD pain intensity numeric rating scale (PI-NRS) according to treatment group at baseline and also at 2-weeks and 4-weeks after randomization. The p-values presented for the 2-week and 4-week after randomization time periods correspond to the treatment effect from analysis of covariance (ANCOVA) with treatment (clonidone versus steroid) as the independent variable and the baseline value included as a covariate. For each treatment group, an asterisk (*) is used to denote significant differences from baseline (paired t-test p

Figure 5

Mean ±SD Roland Morris Disability Questionnaire (RMDQ) according to treatment group at baseline and also at 2-weeks and 4-weeks after randomization. The p-values presented for the 2-week and 4-week post randomization time periods correspond to the treatment effect from analysis of covariance (ANCOVA) with treatment (clonidine versus steroid) as the independent variable and the baseline value included as a covariate. For each treatment group, an asterisk (*) is used to denote significant differences from baseline (paired t-test p