The role of epidural contrast distribution in predicting the effectiveness of steroid and local anesthetic injection in patients with lumbar spinal stenosis

Abstract

STUDY DESIGN:

A prospective observational comparative study.

BACKGROUND:

Because epidural corticosteroids are more effective for pain relief when delivered close to the site of pathology, lumbar spinal stenosis with multilevel stenotic areas can be treated more effectively when medications cover all of the stenotic areas. Distribution of medications to the pathologic sites is considered an important factor in the effectiveness of inter-laminar epidural injection.

OBJECTIVE:

To determine whether spread of a lidocaine and triamcinolone mixture over the stenotic areas improves clinical symptom of spinal stenosis more effectively.

METHODS:

Twenty-four patients with lumbar spinal stenosis were enrolled in this study. A lumbar inter-laminar epidural injection under fluoroscopic guidance was administered to each patient. A numeric rating scale (NRS), claudication distance, the Romberg test, and the Oswestry Disability Index (ODI) were checked pre-injection and at 2, 6, and 12 weeks after the epidural injection. Vertebrae that showed more than moderate stenosis were considered stenosis levels. Inter-laminar epidural injection was performed with radiopaque contrast and lidocaine mixed with triamcinolone acetate. When the contrast covered all of the stenosis levels, this was considered a sufficient distribution (SD) and when the contrast did not cover all stenosis levels, this was considered an insufficient distribution (ID).

RESULTS:

At 2 weeks, percentages of NRS improvement were 71.4 (IQR, 20.2) in SD group and 50.0 (IQR, 31.4) in ID group ( $P=$ 0.02), changes in Romberg test time were 0.0 (IQR, 35.0) in SD group and $-$ 3.0 (IQR, 12.0) in ID group ( $P=$ 0.02), decreases in ODI were 9.6 (IQR, 11.2) in SD group and 0.0 (IQR, 7.8) in ID group ( $P=$ 0.02). However, these parameters were not significantly different at 6 weeks and 12 weeks. Claudication distance showed no significant group difference.

CONCLUSION:

Coverage of the stenotic area by the lidocaine, triamcinolone, and contrast dye mixture during inter-laminar epidural injection was an important predictor of acute pain reduction.