Objective: Chronic low-back pain (LBP) is a leading cause of disability worldwide, and traditional pharmacotherapy fails to provide relief for many individuals with this condition. An estimated 15% of chronic LBP cases can be attributed to the facet joint. High-intensity focused ultrasound (HIFU) is a recent technology that enables noninvasive thermal ablation of tissue and has shown efficacy in treating tumors, neuropathic pain, and painful bone metastases. In this systematic review, the authors summarize the literature on lumbar facet joint-mediated pain treated with HIFU and report the effectiveness of HIFU on pain outcomes.
Methods: All full-text English-language articles describing the use of focused ultrasound for facet joint pain were screened using the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, and Web of Science databases. Clinical studies were assessed for bias using the methodological index for nonrandomized studies.
Results: Eleven studies (6 preclinical and 5 clinical) reporting on 50 patients were included. Eight of these studies (73%) used MR-guided focused ultrasound ablation and 3 used fluoroscopy. The medial branch nerve and posterior facet joint capsule were the most common targets for focused ablation. Although the energy used ranged from 300 to 2000 J, clinical studies predominantly operated in the range of 1000 to 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.
Conclusions: HIFU can be effective in treating chronic low-back pain arising from the facet joint. Further clinical studies should explore the long-term effects of HIFU and monitor changes in pain reduction over time.
Keywords: back pain; facet joint pain; high-intensity focused ultrasound.