Background: Intraoperative identification of early gastric cancer is difficult to conduct during laparoscopic procedures. In this study, we investigated the feasibility and accuracy of a newly developed marking system using endoclips with radio frequency identification (RFID) tags in a canine model.
Methods: RFID is a wireless near field communication technology. Among the open frequency bands available for medical use, 13.56 MHz is suitable for a surgical marking system because of the similar and linear signal decay both in air and in biological tissues. The proposed system consists of four parts: (a) endoclips with RFID tags, (b) endo-clip applier equipment, (c) laparoscopic locating probe, and (d) signal processing units with audio interface. In the experimental setting using canine models, RFID-tagged endoclips were applied to the mucosa of each dog's stomach. During the subsequent operation, the clips with RFID tags placed in five dogs were located by the detection of the RFID signal from the tag (RFID group), and the conventional clips in the other six dogs were located by finger palpation (FP group). The detected sites were marked by ablation on the serosal surface. Distance between the clips and the metal pin needles indicating ablated sites were measured with X-ray radiographs of the resected specimen.
Results: All clips were successfully detected by the marking system in the RFID group (10/10) and by finger palpation in the FP group (17/17). The medians of detection times were 31.5 and 25.0 s, respectively; the distances were 5.63 and 7.62 mm, respectively. The differences were not statistically significant. No adverse event related to the procedures was observed.
Conclusions: Endoclips with RFID tags were located by our novel marking system in an experimental laparoscopic setting using canine stomachs with substantial accuracy comparable to conventional endoclips located by finger palpation through an open approach.