Trident Multi-tined Cannula for Cervical MBRFA Compared to the Conventional Cannula

Cervical medial branch radiofrequency ablation (CMBRFA) is an effective treatment for cervical facet pain. The efficacy of CMBRFA was proven by studies published in the late 1990's and early 2000's. Patients were selected by a strict, labor-intensive placebo-controlled, diagnostic block protocol and were treated using a conventional monopolar cannula that was positioned parallel to the medial branch, two to three lesions per medial branch nerve and both sagittal and oblique passes. Since the original CMBRFA publications, patient selection for CMBRFA is less strict, and new RFA cannulae have been developed to improve efficiency and safety while maintaining a large ablative lesion.

Current clinical patient selection criteria for CMBRFA tend to be more relaxed than described in early research studies. However, subsequent research has shown that when selection criteria are too relaxed, outcomes are poorer. A recent cross-sectional study reported that when CMBRFA is done in patients selected by \>80% pain improvement after dual medial branch blocks, outcomes are similar to patients selected with a stricter selection protocol (100% pain relief) similar to the original CMBRFA studies. Although, the cross-sectional study suggests an appropriate selection criteria, it has not been used in any prospective studies.

The Trident multi-tined cannula is a recent technology that produces a large ablative lesion distal to the triple-tined tip. This design allows a perpendicular/lateral approach to CMBRFA and only requires a single lesion at each medial branch. This differs from the conventional cannula, which produces it's most extensive ablative lesion along the cannula with minimal distal projection. As a result, it requires a parallel approach with multiple burn cycles at the same medial branch. The perpendicular approach with Trident and single lesion cycle at each medial branch are appealing for safety purposes and efficiency however, it's efficacy has not been directly compared to the standard conventional cannula.

Problem: There are no randomized controlled trials comparing novel technologies like Trident cannula to the previously studied conventional cannula in patients selected with a more practical selection criteria.

Purpose: To compared procedural characteristics, pain, and disability outcomes of CMBRFA using either a Trident or conventional cannula in patients with confirmed facet mediated pain (defined by ≥80% symptom reduction after dual medial branch block).

Central Hypothesis: Trident cannula during CMBRFA will result in noninferior improvements in pain and function compared to conventional cannula but will significantly reduce procedural discomfort, time and radiation exposure.

Specific Aims:

1. Determine the proportion of patients with a successful pain response (defined as ≥50% improvement in index pain) to Trident (T-CMBRFA) versus conventional (C-CMBRFA) at 3, 6, and 12 months. 2. Determine the proportion of patients with a successful functional response (defined as ≥10% reduction on neck disability index \[NDI\]) to T-CMBRFA versus C-CMBRFA at 3, 6, and 12 months. 3. Determine the proportion of patients with a successful perception of improvement (defined as a score ≥6 on the Patient Global Impression of Change \[PGIC\]) to T-CMBRFA versus C-CMBRFA at 3, 6, and 12 months.