A Novel Device, Countertraction-Spring, Is Easier and Safer for Endoscopic Submucosal Dissection of Mucosal Stomach Cancer

Abstract

Purpose: To safely perform endoscopic submucosal dissection (ESD) with a good field of view using a spring to apply countertraction during surgery. Methods: According to basic experiments, traction forces of 1-20 gram provide effective countertraction on the gastric mucosa. We invented a novel countertraction device that consists of a stainless steel-spring that is 2 mm in diameter, 2 cm long, and has a wire diameter of 0.1 mm, an approximately 10 fold stretch distance in this range of traction forces, and a nylon loop attached to each of its ends. (1) Allowing a 5 mm margin around the mucosal lesion, the entire circumference is incised. (2) The spring, set in the middle of a 2.5-mm diameter tube that passes through the 2.8-mm forceps channel of an endoscope, is introduced into the stomach via the forceps channel. (3) Countertraction is applied by attaching one of the loops to one end of the lesion with a clip, and attaching the other loop to the healthy mucosa on the other side. (4) The submucosal layer is dissected. (5) The clip attached to the mucosa on the other side is released, and the lesion and spring are retrieved. Results: After obtaining the patients' informed consent, ESD with the novel device was performed on 5 male and 5 female patients between November 2006 and November 2007. The patients' ages ranged from 64 to 82 years (mean: 72.6), and the locations of the tumors were: Lower, Less 6; Lower, Gre, 2; Lower, Post 1; and Middle-Upper, Less 1. According to macroscopic type, there were 8 IIa cases, 1 IIa + IIc case, and 1 IIc case. Mean diameters of the lesions were 20.4 mm × 14.5 mm; mean diameters of the resected specimens were 42.7 mm x 33.9 mm; mean full-circumference incision time was 28 min; mean spring placement time was 4.7 min; and mean submucosal dissection time was 20.5 min. Dissection was possible with sufficient countertraction and a good field of view in every case. There were no complications, and the patients were discharged after a mean hospital stay of 7.8 days. With the exception of 1 case with final pathological diagnosis of adenoma (resection margin negative) and 1 case submucosal invasion 250 micrometer in which additional surgery was performed by positive vertical margin, the pathological findings showed that all of the cases were well differentiated mucosal cancers with negative resection margins and no vascular invasion, and that complete resection had been performed. Conclusion: The countertraction-spring provided favorable countertraction for submucosal dissection of mucosal stomach cancer and this device made the dissection technique easier and safer.