1. 2018;21;E57-E62The Effect of Caudal Epidural Pulsed Radiofrequency Stimulation in Patients with Refractory Chronic Idiopathic Axonal Polyneuropathy
   Prospective Study
   Dong Gyu Lee, MD, and Min Cheol Chang, MD.

BACKGROUND: Many patients with chronic idiopathic axonal polyneuropathy (CIAP) suffer from neuropathic pain, which is managed using several oral medications and modalities. However, despite these treatments, pain persists in some patients.

OBJECTIVE: In the clinical field, clinicians frequently meet patients with neuropathic pain caused by CIAP. The authors investigated the effect of caudal epidural pulsed radiofrequency (PRF) for the management of CIAP-induced refractory neuropathic pain.

STUDY DESIGN: This is a prospective study.

SETTING: The outpatient clinic of a single academic medical center in Korea

METHODS: Twenty patients with neuropathic pain and a diagnosis of refractory CIAP were recruited. For PRF stimulation, a 22-gauge cannula was inserted into the epidural space through the sacral hiatus under fluoroscopic guidance. PRF stimulation was administered once at 5 Hz with a 5-ms pulse width for 600 seconds at 55 V. The effect of stimulation was evaluated using a numeric rating scale (NRS) at 2 weeks and 1, 2, and 3 months after the procedure. Successful pain relief was defined as a reduction in the NRS score of >/=  50% as compared with the score prior to treatment. In addition, at 3 months after treatment, patient satisfaction levels were examined; patients that reported “very good” (score = 7) or “good” (score = 6) results were considered to be satisfied with the procedure.

RESULTS: Neuropathic pain was significantly reduced at 2 weeks and at 1, 2, and 3 months follow-up after PRF (P < 0.001, repeated measures one-factor analysis). In addition, at 3 months post-PRF, half of the patients achieved a successful response (>/= 50% pain reduction) and were satisfied with treatment results.

LIMITATIONS: A small number of patients were recruited, and we did not perform long-term follow-up.

CONCLUSION: Caudal epidural PRF may be a good treatment option for managing neuropathic pain induced by CIAP, especially when pain is unresponsive to oral medications.

KEY WORDS: Pulsed radiofrequency, chronic idiopathic axonal neuropathy, caudal epidural stimulation, neuropathic pain chronic pain, refractory pain