1. 2021;24;E883-E892Alleviating Paravertebral Muscle Spasm after Radiofrequency Ablation Treatment of Hypersensitive Basivertebral and Sinuvertebral Nerves for Chronic Discogenic Back Pain
   Prospective Study
   Ji Yeon Kim, MD, Hyeun Sung Kim, MD, PhD, Pang Hung Wu, MBBS, FRCS, and Il-Tae Jang, MD, PhD.

BACKGROUND: Paraspinal muscle spasm caused by pain from a lumbar degenerative disc is frequently investigated in patients with low back pain. Radiofrequency ablation (RFA) surgery could alleviate paraspinal muscle spasms.

OBJECTIVES: We performed RFA surgery on the high-intensity zone (HIZ) and hypersensitive sinuvertebral and basivertebral nerves to evaluate its outcome. The paravertebral muscle cross-sectional area (CSA) was measured on magnetic resonance imaging (MRI) before and after surgery to evaluate the effect of RFA surgery on the paravertebral muscle.

STUDY DESIGN: Prospective cohort study.

SETTING: A single spine surgery center.

METHODS: A comparative study was performed on 2 different uniportal spinal endoscopic surgery groups; 23 patients who underwent RFA surgery for chronic discogenic back pain and 45 patients who underwent posterior decompression surgery for lumbar spinal stenosis with 12 months of follow-up. Paravertebral muscle cross-sectional area, Schiza grade, Modic type, and HIZ size were measured on pre- and post-operative MRI. An endoscopic video review was performed to evaluate the presence of intraoperative twitching and grade the degree of epidural neovascularization and adhesion. Visual analog scale VAS, modified Oswestry Disability Index, ODI and MacNab’s criteria were evaluated for outcome measures.

RESULTS: Intraoperative endoscopic video evaluation showed neovascularization and adhesion adjacent to the disc and pedicle. In the RFA surgery group, there were 7 patients (30.43%) with grade 2 and 16 (69.57%) with grade 3 neovascularization; intraoperative twitching was observed in 19 out of 23 patients (82.61%). After performing an RFA on the sinuvertebral and basivertebral nerves for the treatment of discogenic back pain, the results showed significant improvement in pain and disability scores. The mean CSA of the paraspinal muscle in the RFA surgery group was significantly increased after surgery at the L4–L5 and L5–S1 levels (L4–L5: 3901 ± 1096.7 mm² to 4167 ± 1052.1 mm², P = 0.000; L5-S1: 3059 ± 968.5 mm² to 3323 ± 1046.2 mm², P = 0.000) compared to preoperative CSA.

LIMITATIONS: This study was limited by its small sample size.

CONCLUSION: Hypersensitive sinuvertebral and basivertebral nerves are strongly associated with epidural neovascularization with adhesion and the pathological pain pathway in degenerative disc disease. Epidural neovascularization with adhesion reflects aberrant neurological connections, which are associated with reflex inhibitory mechanisms of the multifidus muscle, which induces spasm. RFA treatment of the region of epidural neovascularization with adhesion effectively treated chronic discogenic back pain and could induce paraspinal muscle spasm release.

KEY WORDS: Discogenic back pain, high-intensity zone, sinuvertebral nerve, basivertebral nerve, radiofrequency ablation, multifidus muscle