Endoscopic Submucosal Dissection Using Hook Knife for Superficial Gastric Cancers

Abstract

EMR was a useful method for the treatment of the superficial gastric cancers but the resected size was too small and en bloc resection rate was low. The local recurrent rate of piecemeal resected cases was higher than that of en bloc resected cases. Therefore, we developed a novel method, endoscopic submucosal dissection using hook knife. Procedure of ESD: At the first, we placed marks around the lesion with hook knife using 40 W forced coagulation mode (VIO 300D, ERBE). Next, glycerol was injected into the submucosal layer to separate the mucosa from the proper muscular layer. Then, we cut the mucosa around the lesion using needle knife or hook knife with dry cut mode (60 W, effect 5). Finally, the submucosal fibers and vessels were cut using hook knife with dry cut mode (60 W, effect 5). Sometimes, bleeding might occur while cutting the submocosal vessels. We could cut the vessels those sizes were 1 mm or less without bleeding, if we used spray mode (effect 2, 60 W). And, if it caused bleeding, you could treat the bleeding with hook knife, too. A moment of spray coagulation is useful to stop the bleeding, when hook knife was controlled to touch the bleeding vessels. If the bleeding continued, the hemostatic forceps with soft coagulation mode is useful for hemostasis. Patients and Methods: 434 cases of gastric superficial cancers were treated by ESD with hook knife. Four factors were investigated to know the effectiveness of ESD. 1. En bloc (single piece) resection rate, 2. Complete resection rate (single piece, lateral margin (-) and vertical margin (-)), 3. Size of specimens and tumors. 4. Complications. Results: 1. En bloc resection rate was 97.7% (424/434). En bloc resection was impossible in ten cases. The causes of failure were ulcer scars (six cases) and inadequate snaring (four cases). 2. The rate of complete en bloc resection is 91.2% (396/434). The cause of failure was inadequate diagnosis of lateral extension. 3. The mean size of tumors was 18 mm (3-110 mm) and the mean size of specimens was 35 mm (14-146 mm). A large and precise resection could be performed by ESD with the hook knife. 4. Complications: Perforation rate was 0.92% (4/434) and every case could be treated by endoclips. ESD with the hook knife was a safety method. Conclusions: Hook knife is a useful device not only to cut the mucosa, submucosal fibers and small vessels but also to stop the bleeding. ESD with the hook knife is a novel endoluminal surgery method. EMR was a useful method for the treatment of the superficial gastric cancers but the resected size was too small and en bloc resection rate was low. The local recurrent rate of piecemeal resected cases was higher than that of en bloc resected cases. Therefore, we developed a novel method, endoscopic submucosal dissection using hook knife. Procedure of ESD: At the first, we placed marks around the lesion with hook knife using 40 W forced coagulation mode (VIO 300D, ERBE). Next, glycerol was injected into the submucosal layer to separate the mucosa from the proper muscular layer. Then, we cut the mucosa around the lesion using needle knife or hook knife with dry cut mode (60 W, effect 5). Finally, the submucosal fibers and vessels were cut using hook knife with dry cut mode (60 W, effect 5). Sometimes, bleeding might occur while cutting the submocosal vessels. We could cut the vessels those sizes were 1 mm or less without bleeding, if we used spray mode (effect 2, 60 W). And, if it caused bleeding, you could treat the bleeding with hook knife, too. A moment of spray coagulation is useful to stop the bleeding, when hook knife was controlled to touch the bleeding vessels. If the bleeding continued, the hemostatic forceps with soft coagulation mode is useful for hemostasis. Patients and Methods: 434 cases of gastric superficial cancers were treated by ESD with hook knife. Four factors were investigated to know the effectiveness of ESD. 1. En bloc (single piece) resection rate, 2. Complete resection rate (single piece, lateral margin (-) and vertical margin (-)), 3. Size of specimens and tumors. 4. Complications. Results: 1. En bloc resection rate was 97.7% (424/434). En bloc resection was impossible in ten cases. The causes of failure were ulcer scars (six cases) and inadequate snaring (four cases). 2. The rate of complete en bloc resection is 91.2% (396/434). The cause of failure was inadequate diagnosis of lateral extension. 3. The mean size of tumors was 18 mm (3-110 mm) and the mean size of specimens was 35 mm (14-146 mm). A large and precise resection could be performed by ESD with the hook knife. 4. Complications: Perforation rate was 0.92% (4/434) and every case could be treated by endoclips. ESD with the hook knife was a safety method. Conclusions: Hook knife is a useful device not only to cut the mucosa, submucosal fibers and small vessels but also to stop the bleeding. ESD with the hook knife is a novel endoluminal surgery method.