Developmental Endoscopy Unit, Division of Gastroenterology and Hepatology, Mayo Clinic, 200 First Street SW, Charlton 8, Rochester, MN 55905, USA.
Gastrointest Endosc. 2012 Oct;76(4):829-34. doi: 10.1016/j.gie.2012.05.037. Epub 2012 Jul 31.
Endoscopic submucosal dissection (ESD) has appeal for en bloc resection of large flat colorectal polyps but carries appreciable risk and demands a high level of expertise and training. Undermining flat and laterally spreading colorectal polyps by using submucosal endoscopy with the mucosal safety valve flap (SEMF) may be combined with ESD to offer a hybrid technique that is easier and safer.
To determine the feasibility of combining SEMF and ESD for the removal of progressively larger areas of the mucosa in the porcine rectum and colon.
Two-phase ex vivo and in vivo study using domestic pig rectum and distal colon.
Developmental endoscopy unit/animal research unit.
Progressively larger targeted mucosal dissections were performed by using the basic principles of ESD, which included margination of the targeted area of mucosa, submucosal fluid cushion, and needle-knife dissection. These were combined with the SEMF method of predissection with carbon dioxide (CO(2)) gas and balloon-based blunt dissection of the submucosa undermining the targeted and isolated mucosa. The hybrid technique was first applied to ex vivo porcine rectums and distal colons, then in vivo in an acute animal study. Progressively larger staged dissections were performed with 2-, 4-, and 6-cm diameter targeted mucosal sites.
Success with associated difficulty or failure of the hybrid method in the rectum and distal colon to achieve complete resection of a progressively larger targeted area of mucosa.
The ex vivo phase of the experiment demonstrated the ability to use the blunt balloon dissection of the SEMF procedure to remove 2-, 4-, and 6-cm areas of rectum and distal colon with a rapid progression to the largest size resection. The colon proximal to 20 cm above the anus was unable to hold a submucosal fluid cushion and allow submucosal dissection. Successful hybrid ESD was performed in vivo with staged progression through to the largest mucosal area (6 cm) within 20 cm of the anus. Dissections became progressively easier and faster to perform and dependent on the following steps: a traditional circumferential mucosal incision into the deep submucosa, an initial needle-knife submucosal "tunnel" dissection above the muscularis propria (MP), balloon dissection, and needle-knife release of persistent tethering strands of submucosa with and without vessels. Of 16 hybrid resections, 3 failures and 2 very difficult resections were attributed to attempts at resection too proximal in the colon, excessive flexibility of the balloon catheter, and electrosurgical device subperformance. There were no mucosal perforations or coagulation injuries to the MP. A single uninflated balloon catheter perforation of the MP occurred in a dissection site just above 20 cm from the anus with a suboptimal fluid cushion.
Animal study. Procedures performed by a single endoscopist with long-standing familiarity with the SEMF method.
Large mucosal target sites in the rectum and distal colon of the pig can be safely removed en bloc by means of a hybrid technique, ie, submucosal endoscopy with mucosal resection, combining elements of ESD with our SEMF method.
内镜黏膜下剥离术（ESD）对于整块切除大型平坦结直肠息肉具有吸引力，但存在相当大的风险，需要高水平的专业知识和培训。通过使用黏膜安全瓣瓣下黏膜下内镜（SEMF）对平坦和侧向扩展的结直肠息肉进行剥离，结合 ESD 可能会提供一种更简单、更安全的混合技术。
确定 SEMF 和 ESD 联合用于去除猪直肠和结肠中逐渐增大的黏膜区域的可行性。
使用国产猪直肠和远端结肠进行两阶段的离体和体内研究。
发展内镜单位/动物研究单位。
使用 ESD 的基本原则进行逐渐增大的靶向黏膜切开术，包括目标黏膜区域的边缘、黏膜下液垫和针刀切开。这些技术与预切开的 SEMF 方法相结合，使用二氧化碳（CO₂）气体和基于球囊的钝性黏膜下剥离术来剥离目标和孤立的黏膜。该混合技术首先应用于离体猪直肠和远端结肠，然后在急性动物研究中进行体内应用。通过 2cm、4cm 和 6cm 直径的靶向黏膜部位进行逐步分期切开。
混合方法在直肠和远端结肠中成功完成，相关难度或失败，以实现逐渐增大的靶向黏膜区域的完全切除。
实验的离体阶段证明了使用 SEMF 程序的钝性气囊剥离术能够快速切除 2cm、4cm 和 6cm 大小的直肠和远端结肠区域，直至最大尺寸的切除。距肛门 20cm 以上的结肠无法保持黏膜下液垫并允许黏膜下剥离。体内成功进行了混合 ESD，通过分期进展到距肛门 20cm 以内的最大黏膜区域（6cm）。切开术变得越来越容易和快速，取决于以下步骤：传统的环形黏膜切口进入深部黏膜下，肌层上方初始针刀黏膜下“隧道”切开术，气囊剥离术以及针刀释放有或无血管的持续牵丝的黏膜下。在 16 例混合切除中，3 例失败和 2 例非常困难的切除归因于结肠近端切除尝试、气囊导管过度灵活性以及电外科设备性能下降。没有黏膜穿孔或 MP 凝固损伤。在距肛门 20cm 以上的一个切开部位，由于不理想的液垫，单次未充气的气囊导管刺穿了 MP。
动物研究。由一位对 SEMF 方法具有长期熟悉经验的内镜医生进行的程序。
猪直肠和远端结肠的大黏膜靶区可以通过一种混合技术（即黏膜下内镜与黏膜切除术相结合的方法）安全地整块切除，该技术结合了 ESD 的元素和我们的 SEMF 方法。
