The emerging role of fluoroscopy-guided high-intensity focused ultrasound ablation in lumbar facet joint pain management
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Dear Editor,
Chronic low back pain, particularly from lumbar facet joint dysfunction, remains a significant clinical challenge worldwide [1]. Although radiofrequency ablation (RFA) and steroid injections are standard treatments, they are invasive procedures with associated risks such as infection and extended recovery times [2]. Fluoroscopy-guided high-intensity focused ultrasound (HIFU) ablation is a novel, non-invasive alternative for pain management that addresses the many drawbacks of invasive procedures and provides effective pain relief with reduced risks and complications [3,4]. HIFU ablation offers advantages over RFA and magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS) in terms of cost, procedural time, and precision [1,3].
Many clinical studies on HIFU ablation for lumbar facet joint pain have used MRI guidance. However, significant barriers to its widespread adoption include the high cost of MRI machines, long procedural times, and cumbersome setup within MRI scanners, which make clinical implementation challenging [1,3]. In contrast, fluoroscopy-guided HIFU offers several practical advantages. Fluoroscopy is widely available in clinical settings, is more cost-effective, and allows real-time visualization of bony structures, making it easier to accurately target pain-generating regions of the facet joint [3,4].
Fluoroscopy-guided HIFU ablation combines the non-invasive advantages of HIFU with the practicality and cost-effectiveness of fluoroscopic procedures, making the transition feasible for practitioners already familiar with RFA. While fluoroscopy exposes patients to a small amount of radiation, the risk is minimal (comparable to that of RFA) and far less complex than that of MRgFUS [1,3].
Fluoroscopy-guided HIFU ablation requires no needles or probes, thereby offering a significant reduction in the risk of infections and complications associated with invasive procedures such as RFA. Additionally, it is more cost-effective than MRI-guided systems and RFA as it lowers both the procedural costs and recovery times compared with MRI-guided systems and hospital stays compared with RFA [3,4]. A shorter procedural time benefits both healthcare providers and patients by reducing resource utilization and enhancing recovery.
HIFU ablation works by directing focused ultrasound waves to the medial branch (MB) nerve, generating heat that thermally ablates the nerve tissue responsible for transmitting pain signals from the lumbar facet joint [3]. Fluoroscopic guidance ensures precise targeting, minimizing the risk of affecting surrounding structures [3,4]. This non-invasive approach is distinguished from RFA, which requires the insertion of probes, thereby increasing the potential for infection and tissue damage. In comparison, HIFU ablation allows for a more comfortable and quicker recovery [3].
A key distinction between fluoroscopy-guided HIFU ablation, MRgFUS, and RFA lies in the targeted ablation sites. RFA primarily targets the proximal part of the MB nerve, located at the junction of the transverse and superior articular processes. By applying heat to this area, RFA disrupts pain transmission from the lumbar facet joint [2]. This approach requires more oblique fluoroscopic angulation, which increases the risk of affecting the surrounding structures such as the lateral branches, and potentially affecting muscular innervation [3–5].
In contrast, for fluoroscopy-guided HIFU ablation, a more distal portion of the MB nerve at the same junction is targeted [3]. This distal approach reduces the need for oblique angulation, allowing for more selective ablation of the articular twigs while sparing the lateral branches, thus preserving muscular innervation. The result is more effective pain management with less impact on the surrounding tissues, offering a refined and less invasive alternative to RFA [4,5]. However, MRgFUS uses a different approach, targeting the posterior facet joint capsule. This strategy may offer a safer option in some cases because the osseous facet joint prevents further penetration of ultrasound waves, thus protecting deeper neural structures [1].
Perez et al. [3] conducted a clinical pilot study to test the safety and effectiveness of HIFU neurotomy in patients with lumbar zygapophyseal joint pain. They found that 90% of the patients experienced significant pain relief after one month. However, the effectiveness decreased to 40% by 12 months. Despite a reduction in long-term effectiveness, no major side effects were reported. This suggests that HIFU is a safe alternative to invasive treatments. Gofeld et al. [4] also conducted a prospective study comparing HIFU and RFA. They found that HIFU provided similar levels of pain relief but with fewer complications and a faster recovery.
In a preclinical study using a porcine model, Gofeld et al. [5] tested different HIFU energy levels to optimize HIFU use. Their findings showed that higher energy doses led to better nerve ablation with minimal damage to surrounding tissues. These results provide support for HIFU ablation as a reliable and effective treatment option for lumbar facet joint pain.
Fluoroscopy-guided HIFU ablation has the potential to revolutionize the management of lumbar facet joint pain. As a less complex alternative to MRgFUS and a non-invasive option compared to RFA and steroid injections, HIFU ablation provides patients with safer, faster, and more cost-effective treatment options. Future research should focus on comparing the long-term outcomes of HIFU ablation and RFA, as well as refining procedural protocols to maximize safety and efficacy. Further exploration of using HIFU to treat other conditions, such as sacroiliac joint pain and cervical facet syndrome, could expand its use in clinical practice [3,4].
Fluoroscopy-guided HIFU ablation is thus a promising innovation in the management of lumbar facet joint pain. Early evidence suggests that it provides effective pain relief with fewer complications than traditional treatments, such as RFA, steroid injections, and even MRgFUS [1–3]. Although further research is necessary to establish its long-term outcomes and cost-effectiveness, HIFU has the potential to become a key tool for pain specialists in the coming years.
Notes
Funding: None.
Conflicts of Interest: No potential conflict of interest relevant to this article was reported.
Author Contributions: Wasimul Hoda (Conceptualization; Validation; Writing – original draft; Writing – review & editing); Khushboo Pandey (Conceptualization; Data curation; Validation; Writing – review & editing)