Focused Ultrasound for the Treatment of Facet Joint Pain: A Systematic Review

Introduction: Chronic low back pain is a leading cause of disability worldwide. Many patients suffering from chronic low back pain do not experience pain relief with traditional pharmacotherapy. An estimated 15% of chronic low back pain cases can be attributed to the zygapophyseal or facet joint. High-intensity focused ultrasound is a recent technology that enables non-invasive thermal ablation of tissues and has shown efficacy in treating tumors, neuropathic pain, and painful bone metastases. In this study, we summarize the literature on lumbar facet joint-mediated pain treated with HIFU and report the effectiveness of this intervention on pain outcomes.

Methods: All full-text English-language manuscripts studying the use of focused ultrasound for facet joint pain were screened using the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, and Web of Science databases

Results: Eleven studies were included, divided into 6 preclinical and 5 clinical with 50 patients. Of these, 8 studies (73%) used magnetic resonance-guided focused ultrasound (MRgFUS) ablation for their experiments, whereas 3 studies utilized fluoroscopy. The medial branch nerve (MBN) and posterior facet joint capsule were the most common targets for focused ablation. While the energy used varied between 300 and 2000 J, clinical studies predominantly operated in the energy range of 1000-1500 J. Pain reduction was seen in all clinical studies, with multiple-point reductions from average baseline pain scores in 6-12 months. No study reported any adverse events or complications.

Conclusion : HIFU may be effective in treating chronic back pain arising from the facet joint. Further clinical studies are needed to understand the long-term effects of the treatment and monitor the changes in pain reduction over time.