Reply to Tan et al.

We thank Tan et al. for their interest in our article. I totally agree with their opinion that the pocket-creation method (PCM) mimics the submucosal tunneling method. Actually, the PCM originated from the tunneling method, which I first described in colorectal endoscopic submucosal dissection (ESD) in 2010 [1].

With regard to the history of ESD, I began with a mucosal incision and snaring to precisely determine the lateral margin [2]. However, I soon realized the limitation of the snaring technique for submucosal dissection. Therefore, I started performing ESD with a needle-knife. Since the initial development of ESD, I have been using a small-caliber-tip transparent hood and sodium hyaluronate injection to visualize the submucosal tissue during the dissection because I recognized the importance of a direct approach to the submucosal layer to keep a good vertical margin [3].

As an extension of this approach, I prioritized submucosal dissection over mucosal incision. As a result, the tunneling method of ESD was started. We established PCM based on our experience with the tunneling method of ESD. We changed the technique and the name because we realized that completion of the tunnel, penetrating through the other entry, is cumbersome and not necessary. It is more important to widen the pocket to complete the submucosal dissection under the tumor than to complete the tunnel. With the name “tunneling,” completion of a narrow submucosal tunnel from one entry to the other is emphasized. However, with the name “pocket-creation,” widening of the submucosal pocket to complete the submucosal dissection can be easily imagined.

PCM has some advantages over the tunneling method, as Tan et al. point out. We also believe that PCM is a good strategy at sites in the gastrointestinal tract other than the duodenum. In fact, we found its usefulness in colorectal ESD first, which we reported [4] [5].

• References

• 1 Yamamoto H. Endoscopic submucosal dissection for colorectal tumors. Interventional and therapeutic gastrointestinal endoscopy. Front Gastrointest Res 2010; 27: 287-295
• 2 Yamamoto H, Koiwai H, Yube T. et al. A successful single-step endoscopic resection of a 40 millimeter flat-elevated tumor in the rectum: endoscopic mucosal resection using sodium hyaluronate. Gastrointest Endosc 1999; 50: 701-704
• 3 Yamamoto H, Kawata H, Sunada K. et al. Successful en-bloc resection of large superficial tumors in the stomach and colon using sodium hyaluronate and small-caliber-tip transparent hood. Endoscopy 2003; 35: 690-694
• 4 Hayashi Y, Sunada K, Takahashi H. et al. Pocket-creation method of endoscopic submucosal dissection to achieve en bloc resection of giant colorectal subpedunculated neoplastic lesions. Endoscopy 2014; 46 (Suppl. 01) E421-E422
• 5 Hayashi Y, Miura Y, Yamamoto H. Pocket-creation method for the safe, reliable, and efficient endoscopic submucosal dissection of colorectal lateral spreading tumors. Dig Endosc 2015; 27: 534-535