Clinical effectiveness of caudal epidural pulsed radiofrequency stimulation in managing refractory chronic leg pain in patients with postlumbar surgery syndrome

Abstract

BACKGROUND AND OBJECTIVE:

We evaluated the effect of caudal epidural pulsed radiofrequency stimulation in patients with chronic lumbosacral radicular pain due to postlumbar surgery syndrome who were unresponsive to at least two epidural steroid injections through the interlaminar, transforaminal, or caudal route.

METHODS:

We recruited 25 patients with chronic persistent radicular pain in one or both legs ( $⩾$ 4 on the Numeric Rating Scale [NRS]) despite spinal surgery. They were unresponsive to at least two epidural steroid injections. We retrospectively conducted this study. Electrode needles were placed into the epidural space (S2-3 intervertebral level) through the sacral hiatus, and pulsed radiofrequency stimulation was administered. The outcomes were evaluated using the NRS scores for radicular pain before treatment and 1–3 months after treatment. Successful pain relief was defined as a $⩾$ 50% reduction in the scores at 3 months after treatment.

RESULTS:

The pain scores changed significantly over time ( $p<$ 0.001): pretreatment, 4.9 $\pm$ 0.9; 1 month, 3.6 $\pm$ 1.4; 2 months, 3.8 $\pm$ 1.4; and 3 months, 3.9 $\pm$ 1.4. At 1, 2, and 3 months after pulsed radiofrequency (PRF) procedure, the NRS scores were significantly reduced compared with the scores before the treatment. Eight patients (32%) reported successful pain relief at 3 months after treatment.

CONCLUSIONS:

Although only 32% of the patients with postlumbar surgery syndrome showed successful pain relief after treatment, the result is encouraging because we recruited only patients unresponsive to repeated epidural steroid injections.