Original contribution
A randomized, double-blind, prospective study comparing the efficacy of continuous versus pulsed radiofrequency in the treatment of lumbar facet syndrome

https://doi.org/10.1016/j.jclinane.2008.05.021Get rights and content

Abstract

Study Objectives

To compare the efficacy of continuous radiofrequency (CRF) thermocoagulation with pulsed radiofrequency (PRF) in the treatment of lumbar facet syndrome.

Design

Prospective, randomized, double-blinded study.

Setting

Ambulatory pain clinic at a level-I trauma center and teaching institution.

Patients

50 ASA physical status I, II, and III patients, at least 18 years of age, scheduled to undergo CRF or PRF for lumbar back pain.

Interventions

Target facet joints were identified with oblique radiographic views. Continuous radiofrequency thermocoagulation was delivered at 80°C for 75 seconds, while PRF was delivered at 42°C with a pulse duration of 20 ms and pulse rate of two Hz for 120 seconds.

Measurements

Visual analog scale (VAS) pain assessment and Oswestry Low Back Pain and Disability Questionnaire (OSW) were administered at baseline and then at three months. Comparisons between groups and within groups were made of the relative percentage improvement in VAS and OSW scores.

Main Results

No significant differences in the relative percentage improvement were noted between groups in either VAS (P = 0.46) or OSW scores (P = 0.35). Within the PRF group, comparisons of the relative change over time for both VAS (P = 0.21) and OSW scores (P = 0.61) were not significant. However, within the CRF group, VAS (P = 0.02) and OSW scores (P = 0.03) showed significant improvement.

Conclusions

Although there was no significant difference between CRF and PRF therapy in long-term outcome in the treatment of lumbar facet syndrome, there was a greater improvement over time noted within the CRF group.

Introduction

Percutaneous lumbar facet joint denervation of the medial branch of the dorsal ramus by continuous radiofrequency (CRF) thermocoagulation results in significant pain relief and improved function [1], [2], [3], [4], [5], [6]. Pulsed radiofrequency (PRF), using a lower temperature application of energy, may offer comparable pain relief and cause less post-procedure discomfort, neuritis, or motor nerve damage [7], [8], [9], [10]. While the mechanism of action of PRF is speculative, recent evidence suggests that the electric fields reversibly disrupt transmission of nerve impulses across unmyelinated C-fibers and small myelinated fibers [7]. Pulsed radiofrequency thermocoagulation may allow the dissipation of heat, avoiding the complication of thermal injury, thereby decreasing post-procedure side effects [8], [9], [10]. Tekin et al. has indicated that duration of pain relief following PRF lesioning is less than that with CRF lesioning [11]. This study, is, to date, the first prospective, randomized, double-blinded comparison between CRF and PRF ablation performed in a United States level-I trauma center.

Section snippets

Materials and methods

After receiving institutional review board (IRB) approval from the Henry Ford Hospital's IRB, and after receiving patients' written, informed consent, we enrolled into the study 50 ASA physical status I, II, and III patients who were at least 18 years old, and had unilateral or bilateral lumbar back pain greater than one month in duration, with no radiating symptoms below the knee. Subjects were excluded from the study if they had a history of previous back surgery, presence of neurological

Results

A total of 50 patients received either CRF or PRF treatment equally divided between the two groups. Twenty-six patients (13 patients received CRF and 13 patients received PRF) completed their follow-up evaluation and their data were analyzed (Table 1). At baseline, there were no significant differences between the CRF and PRF groups with respect to VAS or OSW scores. No adverse events were encountered during CRF or PRF lesioning, and no complications were documented three months post-procedure.

Discussion

Low back pain affects two thirds of the adult population and is the most common cause of work-related disability [14]. Some 85% of patients with low back pain are never formally diagnosed with a patho-anatomic condition, which may lead to patient frustration and unresolved pain [14]. Lumbar facet syndrome has been described as a potential cause of mechanical low back pain and affects an estimated 4% to 8% of those low back pain patients without neurological deficits or radiographic evidence of

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