Feasibility Evaluation of a New 19-Gauge and 22-Gauge Preloaded EUS Fiducial Needle in an Ex-Vivo Porcine Model

Abstract

Introduction: Radiation therapy plays a vital role in the treatment of various cancers. Fiducial guided stereotactic body radiotherapy (SBRT) can deliver precise and accurate radiation to the tumor with reduced toxicity compared to fractional external beam radiotherapy. Recently, EUS-guided placement of fiducial markers has been shown to be effective at localizing treatment. Previously, EUS-guided placement required a 19-gauge needle and back-loading individual markers. This method is time consuming and can lead to deployment malfunction. We tested the feasibility, reliability and ease of deployment of fiducial markers using a new pre-loaded EUS-fiducial needle in an ex-vivo porcine model. Objective: To assess the feasibility, reliability, visibility, tactile feedback and ease of deployment under EUS-guidance of a new pre-loaded EUS fiducial needle in both 19 and 22-gauge sizes in an ex-vivo porcine model. Methods: The preclinical 19 and 22-gauge preloaded EUS fiducial needles were evaluated by four expert endosonographers in an ex-vivo porcine model. Each needle had 2 preloaded gold fiducial markers. Solely under EUS-guidance and without the use of fluoroscopy, fiducials were deployed into various locations in an ex-vivo porcine model consisting of paraesophageal, pancreatic and hepatic lesions. Each endosonographer individually tested two needles of each gauge and rated the needle's ability to puncture as well as the reliability, tactile feedback, visibility, and ease of deployment of the fiducials for each pass on a scale of 1-5, 5 being the highest. Results:Table 1 shows the average scores for each of the parameters of the needle rated by the four endosonographers. A total of 24 passes were made with each needle gauge. The average scores for ability to puncture with the 19 and 22 gauge needles were 5 and 4.92 respectively, tactile feedback scores were 4.92 and 5 respectively, visibility scores were 4.96 and 4.92 respectively and ease of deployment scores were 4.96 and 4.87 respectively. Fiducials were reliably deployed in all 48 passes.Table 1: EUS-Guided Fiducial Placement with Preloaded Needles: Average scoresConclusion: Our preclinical experience with this new pre-loaded EUS fiducial needle revealed the needle's ease of use, sonographic visibility and reliable deployment using EUS-guidance only. The preloaded nature of the needle appears to simplify the procedure, has the potential to reduce overall procedure time, and obviate the need for fluoroscopy due to excellent sonographic visibility. Further studies are warranted in humans to determine this needle's clinical impact.