Preventive measures for SpaceOAR placement: Insights from intraoperative video analysis to minimize complications

SpaceOAR, a hydrogel spacer placed between the prostate and rectum reduces rectal toxicity during prostate cancer radiotherapy and is widely used. Although studies supporting its approval in Japan demonstrated its safety, severe complications, such as rectal ulcers, have been reported. Through this study,we aim to propose preventive measures by analyzing intraoperative videos of SpaceOAR placement performed at our institution. We retrospectively reviewed 104 prostate cancer patients who underwent spacer placement at Toranomon Hospital between January 2021 and December 2022. All patients underwent pre-radiotherapy MRI, and the complications were classified using the Clavien-Dindo system. The complication rates were Grade 0 in 99 cases (95 %), Grade 1 in 1 case (1 %), and Grade 2 in 4 cases (3.8 %), with no cases of Grade 3 or higher. Grade 2 complications included prostatitis, rectitis, urinary retention, and a conservatively managed rectal ulcer. Our analysis revealed that complications such as prostatitis, rectitis, and rectal ulcers could have been potentially avoided by improving certain technical aspects of the procedure. Key preventive measures include reducing the number of needle insertions, ensuring accurate needle placement, and confirming proper hydrodissection. This study provides a detailed evaluation of intraoperative techniques associated with SpaceOAR-related complications, offering practical insights to improve procedural safety and optimize patient outcomes.