Ultrasound-guided pulsed radiofrequency of cervical nerve root for cervical radicular pain: a prospective randomized controlled trial

Abstract

Background context: Pulsed radiofrequency (PRF) on cervical dorsal root ganglion (DRG) for pain management in cervical radicular pain is mainly performed via a transforaminal approach under fluoroscopic guidance. Ultrasound-guidance periradicular cervical nerve root intervention raises concern about the neuromodulatory effect. This study aims to evaluate the effectiveness and duration of pain relief between PRF treatment and steroid injection on the cervical nerve roots.

Purpose: To evaluate the efficacy of pulsed radiofrequency for cervical radicular pain.

Study design: A prospective, double-blinded, randomized controlled clinical trial PATIENT SAMPLE: Patients who underwent ultrasound-guided periradicular cervical nerve root PRF or steroid injection from January 2020 to May 2021 at King Chulalongkorn Memorial Hospital (KCMH), Bangkok, Thailand.

Outcome measures: The primary outcome was the pain score at 3 months postprocedure. The secondary outcomes were the duration of pain relief of at least 50%, pain scores at other time points after pain intervention, the amount of rescue pain medications, procedural time, and complications.

Method: Forty-two patients who presented with chronic cervical radicular pain were prospectively randomized into the PRF and steroid groups. Patients in the PRF group received PRF treatment at 42^°C for 4 minutes, followed by the injection of 2% lidocaine 1.5 mL and dexamethasone 10 mg to the targeted cervical nerve root. The steroid group received the same injectate. Patients and pain assessors were blinded. The numerical rating scale (NRS) and the Neck Disability Index (NDI) questionnaires were used for pain intensity and neck functional assessment before and after the procedure. Pain reduction was recorded up to a 9-month follow-up.

Results: Data analysis was obtained from 20 and 21 patients receiving PRF and steroid treatment, respectively. At 3-month postprocedure, there were 70% of patients in the PRF group reported 50% pain reduction compared with 23.8% of patients in the steroid group (p<.01). Moreover, patients in the PRF group had significantly less pain (NRS 2.8±2.7) compared with patients in the steroid group (NRS 5.5±2.6) (p=.01). The neck disability index demonstrated significant improvement at 3 and 6 months (p<.01) after PRF treatment compared with steroid injection alone. The duration, in which pain relief was at least 50%, was significantly longer in patients who received PRF treatment (6.0±4.1 months) compared with those in the steroid group (2.3±2.1 months) (p<.01).

Conclusion: Ultrasound-guided periradicular cervical nerve root PRF exhibited a neuromodulatory effect and was considered effective for patients with cervical radicular pain. It provided a longer duration of pain relief and improvement of neck function for up to 6 months.

Keywords: Cervical nerve root; PRF; Pulsed radiofrequency; Radicular pain; Ultrasound guidance.