Correlation between lumbar lordosis and the treatment of chronic low back pain with pulsed radiofrequency applied to the L2 dorsal root ganglion

Background: Percutaneous pulsed radiofrequency (PRF) applied to the L2 dorsal root ganglion (DRG) is an alternative procedure for treating patients with chronic discogenic pain. It is assumed that afferent nerve fibers innervating the degenerated disc and facet joint might travel in the same pathway and finally enter into the L2 DRG. Blocking the L2 DRG with PRF might alleviate discogenic pain and facet joint pain concurrently. Purpose: The purpose of this study was to investigate the correlation between different types of lumbar lordosis (LL) and the treatment of chronic low back pain with PRF applied to the L2 DRG. Materials and Methods: Between 2008 and 2013, 84 patients (29 men and 55 women) were enrolled. Their mean age was 56.03 ± 9.04 years. All patients suffered from low back pain for more than 6 months that worsened on prolonged sitting or standing and did not improve with at least 3 months of conservative treatment. LL was classified into four types based on Roussouly's classification. The L2 DRG was blocked with 2-Hz PRF waves lasting for 120 s at 45 V with the temperature of the electrode tip not above 42°C. The functional outcomes were assessed pre- and post-operatively using a visual analog scale (VAS) and the Oswestry Disability Index (ODI). Results: Twenty-four patients were Type 1 LL, 26 were Type 2 LL, 21 were Type 3 LL, and 13 were Type 4 LL. The mean age of patients with each type of LL was type 1 (56.63 ± 12.09 years), Type 2 (55.39 ± 11.05 years), Type 3 (55.86 ± 11.40 years), and Type 4 (56.54 ± 12.73 years). There were similar improvements in the VAS and ODI scores for all LL types. Two patients experienced cerebrospinal fluid leakage when the needle was moved toward the L2 DRG, but neither patient experienced a neurological deficit. Conclusion: PRF applied to the L2 DRG is an alternative procedure for treating patients with chronic low back pain, regardless of which type of LL the patients have. Chronic low back pain, including discogenic pain and facet joint pain, may be treated by PRF applied to the L2 DRG. © 2017 Formosan Journal of Surgery.