Technique Considerations to Improve Efficacy in Sacroiliac Radiofrequency Ablation.

Background: Chronic low back pain is a global health burden with significant health care costs. Accurate diagnosis and treatment are often complicated due to its multifactorial nature. The sacroiliac joint has been identified as a major source of lower back pain, especially among the elderly and individuals with a history of lumbar fusion surgery. Conservative treatments frequently fall short in providing relief, leading to the exploration of alternative interventions such as sacroiliac joint radiofrequency ablation (RFA).

Objectives: We aimed to demonstrate a novel approach for sacroiliac joint RFA based on new ex vivo evidence.

Study design: Development of a novel methodology integrating ex vivo evidence and clinical approach.

Setting: Academic health care institution.

Methods: Current radiofrequency methods, such as conventional RFA, water-cooled RFA, and cryoneurolysis, involve 2 main needle placement strategies: the palisading and the strip lesioning techniques. Additionally, the periforaminal/intraforaminal lesion technique, performed with fluoroscopy, visualizes the dorsal sacral foramina by adjusting the beam according to sacral tilt while the patient is prone. Targeting the lateral borders of the S1-S3 foramina, the technique aims to reach described lateral branch neural locations. Needle placement focuses on the lateral borders of the posterior sacral foramina, spaced one mm to 10 mm from the foraminal border, often following a clock face analogy. Protruding electrode RFA needles are recommended because of their demonstrated larger lesion width. After directing the needles to the lateral border of the S1-S3 posterior sacral foramina and then medially into the foramen, a lateral projection confirms proper needle placement beyond the posterior sacral ridge. Sensory-motor testing follows, with 0.5 mL of iohexol 180 administered to assess vascular flow and minimize contrast medium migration. Subsequently, 0.5 mL of lidocaine 2% is given for ablation anesthesia.

Results: This technique achieves an estimated 95% needle approximation of the lateral branches, enhancing neural ablation efficacy by optimizing needle tip positioning.

Limitation: Our technique faces challenges as lesion success rates decrease with distance from the foramen.

Conclusion: Adipose interference is minimized when a protruding electrode RFA needle is used within a posterior sacral foramen; neural approximation may be enhanced by giving 2% lidocaine prior to ablation. Considerable gaps in knowledge still exist despite advances in our understanding of the effect of tissue on RFA. Thorough research aimed at refining RFA procedures is essential to ensuring the best feasible patient care and sustainable pain relief. For sacroiliac joint RFA, perineural lateral branch ablation is a viable option that needs further clinical research.