SPY-QP-guided perfusion assessment to prevent esophagogastric anastomotic leakage: protocol for the SPYMIE study.

backgroundEsophagectomy with gastric conduit reconstruction is one of the standard treatment for esophageal cancer; however, anastomotic leakage remains a major complication, occurring in approximately 13% of cases. Impaired perfusion of the gastric conduit is a key risk factor, highlighting the need for objective intraoperative blood flow assessment. Although indocyanine green (ICG) fluorescence imaging has been used, quantitative evaluation is lacking, and perfusion of the remnant esophagus has not been assessed. The SPY-QP system provides objective, real-time perfusion analysis using fluorescence intensity metrics. This study examines the role of SPY-QP–guided perfusion assessment in supporting intraoperative anastomotic decision-making and explores its association with a reduced incidence of anastomotic leakage compared with conventional near-infrared evaluation.

methodsThis investigator-initiated, prospective, single-arm clinical study (SPYMIE study) aims to evaluate the feasibility and effectiveness of quantitative perfusion assessment using the SPY-QP fluorescence system during minimally invasive esophagectomy for esophageal cancer. Intraoperative ICG fluorescence imaging is performed to quantify blood flow in the gastric conduit and remnant esophagus. The primary endpoint is the incidence of anastomotic leakage, with secondary outcomes including anastomotic stricture, gastric conduit necrosis, and relative fluorescence intensity at anastomotic sites. Historical controls with conventional near-infrared evaluation will be used for comparison. DISCUSSION: Anastomotic leakage after minimally invasive esophagectomy remains a major concern, largely attributed to inadequate perfusion at the anastomotic site. Conventional intraoperative assessments are subjective and lack quantitative reliability. The SPY-QP system enables real-time, quantitative perfusion analysis, providing measurable parameters such as relative ICG fluorescence intensity and time-to-peak intensity. Prior studies demonstrated that SPY-QP detects low-perfusion regions unseen with qualitative imaging and influences surgical decision-making, leading to reduced leakage rates. Therefore, SPY-QP–guided quantitative perfusion assessment may enhance intraoperative blood flow evaluation of anastomotic sites, standardize perfusion-based surgical quality indicators in esophagectomy.

trial registrationThis SPYMIE study was prospectively registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN-CTR) on May 12, 2025 (registration number: UMIN000057825) under the title “Prospective, single-arm study on the usefulness of blood flow evaluation of the gastric conduit and remnant esophagus using the SPY-QP software system in minimally invasive esophagectomy for esophageal cancer.”