1. 2021;24;E185-E190Simplicity Radiofrequency Ablation Demonstrates Greater Functional Improvement Than Analgesia: A Prospective Case Series
   Prospective Case Series
   Brian Boies, MD, Brittany Bickelhaupt, MD, Caroline Brennick, DO, and Ameet Nagpal, MD.

BACKGROUND: Pain originating from the posterior sacroiliac complex is notoriously difficult to effectively treat due to its complex anatomy and variable innervation. Data on radiofrequency ablation (RFA) is limited. The Abbott Simplicity probe creates 3 monopolar lesions along the medial aspect of the sacroiliac joint and 2 bipolar lesions between the active portions of the probe. This device has been studied previously with improvement of pain-associated disability and pain reduction, but insufficient data is present to determine its utility at this time. Using the most recent literature for the potential innervation of the posterior sacroiliac joint, it is reasonable to explore this novel device and its ability to treat sacroiliac joint pain.

OBJECTIVES: Identify the percentage of improved posterior sacroiliac complex pain and improved function in patients who completed posterior sacroiliac complex radiofrequency ablation using the Simplicity probe.

STUDY DESIGN: Prospective case series.

SETTING: A single outpatient pain clinic.

METHODS: This prospective case-series occurred at an outpatient pain clinic. Data were analyzed after completion of follow-up appointments. Inclusion criteria included 2 successful lateral branch blocks. Fourteen patients with posterior sacroiliac complex pain were examined and completed sacroiliac ablation with the Simplicity probe. The numeric rating scale and the Modified Oswestry Disability Index were used as outcome measures for pain and function, respectively. The primary outcome measures were improvement in the numeric rating scale score by a reduction of 2.5 points and an improvement in Modified Oswestry Disability Index by 15% based upon previous studies demonstrating these values as the minimal clinical important difference . Patients were followed at a 3 to 6 month interval and 12 month interval (an average of 88 and 352 days, respectively).

RESULTS: In total, 14 patients were examined. At the first follow-up, 29% of patients had analgesia and 38% functionally improved. At the second follow-up, 15% of patients had analgesia and 31% functionally improved.

LIMITATIONS: Considering data were collected retrospectively, this study relied on completed charts. Therefore, data points of interest were limited to what was previously documented, which included multiple answers or the absence of numerical data points. In addition, patients were disproportionately female (71.4%). Data were also affected by patients lost to follow-up. Also, this study examined a relatively small number of patients, therefore the results should be carefully considered.

CONCLUSIONS: Radiofrequency ablation of the posterior sacroiliac complex with the Simplicity probe resulted in more functional improvement than analgesia. This study provides more data for clinicians to utilize in managing posterior sacroiliac complex pain.

IRB: Protocol number 20170342HU. Not registered in clinical trials.

KEY WORDS: Posterior sacroiliac complex, sacroiliac pain, chronic low back pain, radiofrequency denervation, functional improvement, strip lesion, multi-lesion, Simplicity probe.