Bipolar Radiofrequency for Sacroiliac Joint Pain: Daradia’s Early PubMed-Indexed Case Report and How the Evidence Has Evolved
An early PubMed-indexed contribution from Daradia on bipolar radiofrequency for sacroiliac joint pain.
Chronic low back pain is one of the most frequent causes of disability worldwide. In 15–30% of carefully evaluated patients, the sacroiliac joint (SIJ) is the primary pain generator.¹ For this subgroup, radiofrequency ablation (RFA) of the sensory supply to the SIJ has emerged as a minimally invasive treatment option.
Today, cooled and bipolar RFA techniques for the SIJ are widely discussed. But 14 years ago, when our team at Daradia: The Pain Clinic, Kolkata performed and published a case of conventional bipolar RFA for SI joint arthropathy in a PubMed-indexed journal, this technique was almost absent from the clinical literature.²
This post revisits that early case, explains why bipolar RFA was an important innovation at the time, and summarises how the evidence has evolved since then.
Why the Sacroiliac Joint Is So Difficult to Treat
The SIJ is a complex, partly synovial and partly fibrous joint with relatively small movement but major load-bearing responsibility. Pain can arise after trauma, pregnancy, lumbar fusion, inflammatory disease, or even without a clear inciting event.¹
Diagnosis is challenging because:
- Clinical tests have limited individual accuracy.
- Imaging findings correlate poorly with pain.
- Diagnostic blocks are required to confirm the SIJ as the pain generator.
Once conservative therapy (physiotherapy, medications, bracing) fails, options include steroid injections, RFA, regenerative procedures, and, in selected patients, fusion surgery.³
From Monopolar to Bipolar: What Changes?
Traditional monopolar RFA uses a single active electrode and a grounding pad. Lesions are typically ovoid and relatively small. Because the sensory supply to the posterior SIJ arises from a network of lateral sacral branches with variable anatomy, it is easy to “miss” some fibres with small, discrete lesions.³,⁴
Bipolar RFA connects current between two closely spaced active electrodes. When arranged appropriately, the electric field spans the tissue between them, creating:
- Larger, more contiguous lesions
- Greater “coverage” of the posterior sacral network
- Potentially fewer “missed” nociceptive fibres
Cadaveric and ex-vivo work by Pino et al. and Cosman & Gonzalez showed that bipolar configurations could produce elongated strip-like lesions suitable for SIJ denervation.⁴,⁵ However, these were technical and morphological studies, not real-world clinical outcome reports.
How Early Was Our Bipolar SIJ Case?
In 2012, we published a case report titled “Pain of Chronic Sacro-Iliac Joint Arthropathy: Managed Successfully with Conventional Bipolar Radiofrequency Procedure” in a PubMed-indexed journal.² The procedure itself had been done the previous year.
At that time:
- The clinical RFA literature for SIJ pain was dominated by monopolar techniques and early work on cooled RFA.³,⁶
- Our PubMed search identified only two bipolar SIJ–related publications, both non-clinical:
- A morphologic analysis of bipolar lesions with implications for SIJ treatment⁴
- A detailed modelling paper on bipolar lesion geometry for palisade treatment of SIJ pain⁵
In other words, before our report, there were no published human clinical case reports or series using conventional bipolar RFA specifically for SIJ pain. The concept existed in lesion geometry and experimental work, but not yet as a documented clinical success story.
That is why this single case, though modest in size, was an important early step.
The Daradia Case: Conventional Bipolar RFA of the SI Joint
Our patient had chronic unilateral SIJ arthropathy with:
- Localised pain over the SIJ
- Positive SIJ provocative tests
- Significant short-lived relief after diagnostic and therapeutic blocks
When steroid injections failed to give sustained relief, we planned a conventional bipolar RFA of the posterior sacral network.
Key technical features (summarised from the case report):²
- Target: Lateral branches supplying the painful SIJ
- Guidance: Fluoroscopy
- Configuration: Two active RF electrodes positioned in close parallel alignment over the posterior sacral surface to create a bipolar lesion encompassing the lateral branches
- RF parameters: Conventional continuous RF at lesioning temperature (not cooled) applied in a bipolar configuration
The outcome was encouraging:
- Marked reduction in pain intensity after the procedure
- Functional improvement and sustained relief during follow-up
- No procedure-related complications reported
In the discussion of that paper, we explicitly highlighted that bipolar SIJ RFA had essentially no preceding clinical case data, and that our result aligned with the lesion geometry predictions of Pino et al. and Cosman & Gonzalez.⁴,⁵
How the Evidence Has Evolved Since Then
1. Meta-analyses and Systematic Reviews
Early on, a meta-analysis by Aydin et al. concluded that RFA (mostly monopolar and early cooled techniques) could provide meaningful pain and disability reduction in selected SIJ pain patients, though the evidence base was heterogeneous.³ More recently, the literature has been strengthened by a growing number of controlled and uncontrolled studies, particularly for cooled RFA.⁷,⁸
2. Cooled RFA: Larger Lesions, More Data
Cooled RFA (c-RFA) was introduced to increase lesion size further by internally cooling the electrode tip. This allows delivery of more RF energy without tissue charring, creating larger spherical lesions in the posterior sacral network.⁶
Key milestones include:
- Karaman et al. 2011: 15-patient observational study with fluoroscopy-guided cooled RFA of L5 dorsal ramus and S1–S3 lateral branches. Significant and sustained improvements in pain scores and Oswestry Disability Index at 6 months.⁶
- Sun et al. 2018: PRISMA-compliant meta-analysis of 7 cooled RFA studies (240 patients) showing mean ~3.8-point reduction in pain scores and ~18-point improvement in ODI, with only mild complications.⁷
- Maalouly & Rao 2023: Retrospective cohort of 81 patients treated with cooled RFA, demonstrating substantial reductions in Numeric Pain Rating Score and ODI at follow-up, with a low rate of progression to fusion.⁸
These data have made cooled lateral-branch neurotomy an accepted and widely used modality for SIJ pain.
3. Sequential Bipolar RFA: Strip Lesions for the SIJ
Building on the lesion geometry work that inspired us,⁵ Cheng et al. (2016) described a new bipolar RFA technique for SIJ pain using a guide-block to place multiple parallel electrodes along the posterior sacrum.⁹
Their key contributions:
- A systematic, reproducible way to create long strip bipolar lesions covering L5 dorsal ramus and S1–S3 lateral branches
- A prospective cohort of bipolar RFA (b-RFA) patients compared with a historical cooled RFA (c-RFA) group
- Reduced operating time and X-ray exposure with b-RFA, plus cost savings, while maintaining effective pain relief⁹
In essence, Cheng’s work generalised and expanded the type of bipolar SIJ concept that our early case had shown was feasible in a single patient, and compared it against the then-standard cooled approach.
Where Does Conventional Bipolar RFA Fit Today?
Putting the current literature together:
- Monopolar RFA
- Smaller lesions, technically simpler
- Variable success rates, quite operator-dependent
- Cooled RFA
- Larger lesions, better coverage of variable sacral anatomy
- Supported by multiple observational series, RCTs and meta-analysis⁶–⁸
- Higher equipment cost and specific device requirements
- Conventional bipolar RFA
- Lesions substantially larger than monopolar and more elongated than simple cooled lesions⁴,⁵,⁹
- Can often be implemented with standard RF generators and cannulae (no proprietary cooled system needed)
- Evidence includes:
- Early conceptual / morphologic work⁴,⁵
- Our 2012 Daradia clinical case demonstrating feasibility and benefit in a real patient²
- Later sequential bipolar strip-lesion studies with larger cohorts and technical refinements⁹
In centres where cooled RFA equipment is not available or where cost is a major barrier, conventional bipolar RFA remains a rational, anatomy-guided option, provided the operator understands lesion geometry and sacral innervation.
Take-Home Messages
- The SI joint is a frequent but under-recognised source of chronic low back pain. Careful diagnosis with clinical tests and confirmatory blocks is essential.¹
- Radiofrequency denervation of the posterior sacral network is now an established minimally invasive option for appropriately selected SIJ pain patients.³,⁶–⁸
- When we performed and later published our bipolar SIJ case 14 years ago, there were no prior human clinical reports of conventional bipolar RFA for this indication in PubMed-indexed literature. The only bipolar SIJ data were lesion-geometry and morphologic studies.⁴,⁵
- Subsequent work on cooled and bipolar RFA has validated and extended this concept, showing that larger, better-shaped lesions can translate into meaningful improvements in pain and function.⁶–⁹
- For clinicians, the choice between monopolar, cooled, and bipolar RFA should consider:
- Anatomy and lesion coverage
- Available equipment and cost
- Existing evidence base
- Patient-specific factors and prior responses to treatment
For us at Daradia, that early bipolar SIJ case remains a landmark: it reflects our long-standing commitment to innovating in interventional pain medicine while staying grounded in anatomy, careful technique, and long-term follow-up.
Where else this work is featured:
- Zenodo record: Read on Zenodo
- Medium explainer: Read on Medium
- ResearchGate / Academia: View on ResearchGate / Academia
References:
- Vanelderen P, Szadek K, Cohen SP, De Witte J, Lataster A, Patijn J, et al. 13. Sacroiliac joint pain. Pain Pract. 2010;10(5):470–8.
- Ghazali A, Das G, Horani K, Anand Kumar GS, Mehta P, Dutta D. Pain of chronic sacro-iliac joint arthropathy: managed successfully with conventional bipolar radiofrequency procedure: a case report. Anesth Pain. 2012;1(3):191–3.
- Aydin SM, Gharibo CG, Mehnert M, Stitik TP. The role of radiofrequency ablation for sacroiliac joint pain: a meta-analysis. PM R. 2010;2(9):842–51.
- Pino CA, Hoeft MA, Hofsess C, Rathmell JP. Morphologic analysis of bipolar radiofrequency lesions: implications for treatment of the sacroiliac joint. Reg Anesth Pain Med. 2005;30(4):335–8.
- Cosman ER Jr, Gonzalez CD. Bipolar radiofrequency lesion geometry: implications for palisade treatment of sacroiliac joint pain. Pain Pract. 2011;11(1):3–22.
- Karaman H, Kavak GO, Tüfek A, Çelik F, Yildirim ZB, Akdemir MS, et al. Cooled radiofrequency application for treatment of sacroiliac joint pain. Acta Neurochir (Wien). 2011;153(7):1461–8.
- Sun HH, Zhuang SY, Hong X, Xie XH, Zhu L, Wu XT. The efficacy and safety of using cooled radiofrequency in treating chronic sacroiliac joint pain: a PRISMA-compliant meta-analysis. Medicine (Baltimore). 2018;97(6):e9960.
- Maalouly J, Rao PJ. Cooled radiofrequency ablation of the sacroiliac joint: a retrospective case series. BMC Musculoskelet Disord. 2023;24:261.
- Cheng J, Chen SL, Zimmerman N, Dalton JE, LaSalle G, Rosenquist RW. A new radiofrequency ablation procedure to treat sacroiliac joint pain. Pain Physician. 2016;19(4):603–15.
