Introduction

Effectiveness of monopolar cutting current (MC) during POEM (per oral endoscopic myotomy) varies depending on tissue consistency and body composition. To overcome such variations, a novel bipolar radiofrequency ablation (RFA) cutting knife (BC) was developed. With 3 in 1 (injection, dissection and coagulation) capability function, the BC knife may have high utility during POEM (Figure 1). However, its effectiveness during POEM has yet to be clinically tested. This randomized controlled trial (RCT) compared the clinical efficacy and outcomes of BC vs MC during esophageal POEM.

Methods
This is a non-inferiority RCT study evaluating the effectiveness of BC during esophageal POEM at three high volume institutions and involving six expert submucosal endoscopists between February 2022 – October 2023. Inclusion criteria were patients diagnosed with achalasia or EGJOO (esophagogastric junction outflow obstruction). Primary outcomes were technical success (defined as the ability to perform the entire procedure with the intended knife (MC or BC)), and clinical success (defined as Eckardt score less than or equal to 3 at 1 month follow up). Secondary outcomes included dissection speeds, total procedure times, visual pain score, and need for additional devices.

Results
A total of 71 patients were included (34=BC vs 37=MC) (Table 1) and underwent 1-month post-procedural follow up. Technical success (94.1 vs 100%, p=0.13) and clinical success (94.1 vs 94.6%, p=0.28) were similar between BC and MC, respectively. The two technical failures in the BC group were due to ineffective cutting during the myotomy and the procedure was successfully completed using MC. One patient required a second BC knife due to inability of the first BC knife to rotate. Tunnel dissection speed (0.76 vs 0.60 cm/min, p=0.76) was similar between both groups but total procedure times (69.2 vs 51.2, p=0.004) were shorter in the MC group due to faster myotomy speeds (0.66 vs 1.1 cm/min, p=0.001). 71% of patients in the BC group completed the entire procedure (injection, dissection and myotomy) with one instrument compared to none in the MC (p=0.0001). Only 15% of patients required a coagulation grasper in the BC group compared to 60% in the MC group (p=0.001). Visual pain scores were similar between both groups. Only one major adverse event occurred in the BC group and was managed endoscopically (2.9%) (Table 1).

Conclusion

Use of a novel bipolar RFA knife during POEM showed similar technical and clinical success rates when compared to monopolar knives, while maintaining a high safety profile. Although procedural times were slightly longer with the BC knife, majority of patients completed the entire procedure (injection, cutting and coagulation) with one instrument. Future studies will be performed to determine the cost effectiveness of both knives.

Bipolar RFA knife performing submucosl dissection during POEM with minimal inadvertent cautery effect or eschar formation.

Table 1: Demographics and Procedural Outcomes of Bipolar (BC) and Monopolar Cutting (MC) Knives During Esophageal POEM

Pradev Inavolu

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