Pulsed Radiofrequency on Thoracic Dorsal Root Ganglion Versus Thoracic Paravertebral Nerve for Chronic Postmastectomy Pain, A Randomized Trial: 6-Month Results

Abstract

Background: Pharmacologic treatment is not successful in all cases of postmastectomy pain syndrome (PMPS). Some patients continue suffering pain while taking their medications, and others cannot tolerate the side effects of antineuropathic analgesics. Radiofrequency technology has provided promising results in the management of chronic neuropathic pain.

Objectives: Considering that affection of intercostobrachial nerves are the main reason behind PMPS, we aimed to evaluate and compare the analgesic efficacy of pulsed radiofrequency (PRF) when delivered either on thoracic dorsal root ganglion (DRG) of intercostobrachial nerves (thoracic DRG 2, 3, and 4) or their corresponding thoracic paravertebral nerves (PVNs).

Study design: Prospective randomized-controlled clinical trial.

Settings: Interventional pain unit, tertiary center, university hospital.

Methods: Sixty-four patients complaining of PMPS were randomized to either group DRG (n = 32) that received PRF on thoracic DRG, or group PVN (n = 32) that received PRF on thoracic PVN. The outcome variables were that the patients showed > 50% reduction in their visual analog scale (VAS) pain score; the VAS pain score and global perceived effect (GPE) was evaluated during a 6-month follow-up period.

Results: The percentage of patients who showed > 50% reduction of their VAS pain score was significantly higher in group DRG compared with group PVN, assessed at 4 and 6 months postprocedure (23/29:79.3% vs. 13/29:44.8%; P = 0.007) and (22/29:75.9% vs. 7/29:24.1%; P < 0.001), respectively, however, the 2 groups did not significantly differ at 1, 2, and 3 months postprocedure (DRG vs. PVN), (21/29: 72.4% vs. 21/29: 72.4%; P = 0.542), (24/29: 82.8% vs. 23/29: 79.9%; P = 0.778), and (24/29: 82.8% vs. 19/29: 65.5%; P = 0.136), respectively. There was a statistically significant reduction of VAS pain score at 4 and 6 months (DRG vs. PVN, mean ± standard deviation, 2.9 ± 2 vs. 3.9 ± 1.5; mean difference (95% confidence interval), 1 (0.06:1.9); P = 0.038; 3 ± 1.94 vs. 5.1 ± 1.5; mean difference (95% confidence interval), 1.9 (1:2.9); P < 0.001, respectively), however, the 2 groups did not significantly differ at 1, 2, and 3 months postprocedure. With regard to the patient's satisfaction (i.e., GPE), assessed at 3 and 6 months postprocedure, there was a significantly higher satisfaction in group DRG compared with group PVN (median [interquartile range (IQR)], 6 (5:7) vs. 3 (2:4);P < 0.001), however, the patient's satisfaction was similar between groups at 3 months postprocedure: median (IQR), 6 (4:7) vs. 6 (5:6); P = 0.327.

Limitations: The study follow-up period is limited to 6 months only.

Conclusions: PRF of both the thoracic DRG and the thoracic PVN are effective treatments for PMPS; however, PRF of DRG provided a better long-term analgesic effect. Nevertheless, given the inherent risk of performing thoracic foraminal interventions and the technical difficulty of targeting thoracic DRG, we recommend that PRF of DRG should be reserved for cases that failed to gain adequate response to PRF of thoracic PVN in conjunction with medical treatment.

Key words: Postmastectomy pain syndrome, radiofrequency, dorsal root ganglion, paravertebral nerve.