Yoji Takeuchi, MD; Noriya Uedo, MD; and Ryu Ishihara, MD
Polypectomy is a well-established technique for the endoscopic removal of gastrointestinal (GI) polyps. Most GI polyps are benign but have the potential to become malignant in the future. Thus, polypectomy can be considered as a preventive tool for GI cancer. Niwa1 first reported endoscopic polypectomy for gastric polyps using electrocautery in 1968. Subsequently, Tsuneoka and Uchida2 performed endoscopic polypectomy for gastric polyps without electrocautery in 1969. In the West, Blackwood and Silvis3 reported gastric polypectomy in the canine stomach in 1971, and Deyhle et al4 reported colonic polypectomy in 1971. Several endoscopic removal techniques have since been reported, including endoscopic mucosal resection (EMR),5 inject and snare EMR, cap EMR,6 endoscopic submucosal dissection (ESD),7 and underwater EMR.8 Because of the availability of many techniques, the most suitable technique for each clinical case should be individualized. In all, simple polypectomy, that is, snarectomy without injection or water immersion, is the most commonly used technique. Additionally, cold polypectomy, which is performed without electrocautery, has been gaining popularity recently. It is important to know the pros and cons of each polypectomy technique. Herein, we describe the different techniques of polypectomy and their indications.
Hot polypectomy is performed using electrocautery and can be categorized into 2 types: hot-forceps polypectomy (HFP) or hot biopsy, which uses biopsy forceps with electrocautery, and hot snare polypectomy (HSP), which uses an electrosurgical snare with electrocautery. HSP sometimes includes injection and snare with electrocautery, which is described as inject and snare EMR in this book.
HFP is used to remove diminutive (≤ 5 mm) colorectal polyps.9 Theoretically, HFP provides improved hemostasis and a more complete ablation of the neoplastic tissue.10 During the procedure, it is important to grasp the polyp superficially with the forceps while gently tugging away from the underlying mucosa, and apply force carefully to achieve a white-heated mucosa around the forceps. There are several issues related to HFP, including a high incidence (10.8% to 17%) of viable polyp remnants after HSP,11,12 inferior diagnostic quality of removed specimens compared with those obtained using jumbo cold-forceps polypectomy (CFP),13 a high rate of hemorrhage (0.4%; 1.3% in the cecum and 1.0% in the ascending colon),14 and transmural colonic injury (32% to 44%) in animal studies.15,16 Therefore, the European Gastrointestinal Endoscopy Society (ESGE) currently recommends against the use of HSP.17
Hot Snare Polypectomy
HSP remains one of the standard procedures for endoscopic resection. However, since HSP without submucosal injection cannot guarantee a sufficiently deep margin of the resected specimen, it should not be applied to malignant lesions with suspected submucosal invasion. Thus, HSP without submucosal injection is mainly used for removing gastric pedunculated hyperplastic polyps and colorectal adenomas. The ESGE recommends the use of HSP for the removal of sessile colorectal polyps (size, 10 to 19 mm).17 However, the ESGE also mentions that submucosal injections should be considered prior to HSP for these lesions to avoid deep thermal injury.17 Therefore, HSP without submucosal injection should be used only for small (6 to 9 mm) or diminutive (1 to 5 mm) polyps. Additionally, colorectal pedunculated polyps are favorable candidates for HSP without submucosal injection because most pedunculated lesions can be easily removed completely.
Assistive Devices for Hot Polypectomy
Large pedunculated polyps, which can have a large blood vessel in the stalk, are reported as a risk factor for postpolypectomy bleeding, and the ESGE recommends pretreatment of the stalk with dilute adrenaline injections and/or mechanical hemostasis.17 Mechanical prophylaxis by using an Endoloop or Endo Clip is an effective and easy method for the pretreatment of the stalk. Even for polyps on the inverted appendix, Endoloops can facilitate endoscopic appendectomy without any adverse events (Figure 13-1).18 Endoloops are more difficult to maneuver and less popular than Endo Clips despite being more reliable. Therefore, Endo Clips are usually used for small (< 10 mm) pedunculated colorectal polyps and Endoloops are used for colorectal polyps that are 10 mm.19 Randomized controlled trials have demonstrated that mechanical devices are effective for the prevention of postpolypectomy bleeding when removing polyps that are 20 mm with HSP.20,21 In contrast, the effects of dilute adrenaline injections are controversial22–24 and seem less effective than those of mechanical devices.20,21
Electrosurgical Snares for Hot Polypectomy
Both monopolar and bipolar electrosurgical snares are available for HSP. It is generally accepted that the advantage of bipolar snares is the elimination of the return electrode, and consequently, the possibility of any return electrode burns. Thus, the bipolar snare provides an added safety margin during polypectomy.25 Additionally, bipolar snares do not influence pacemakers. In contrast, bipolar disposable snares are expensive, and the cost-to-safety relationship is unknown. Finally, the size of bipolar snares is limited. Thus, bipolar snares are not mainstream devices but are still useful to avoid electrical interference in patients with a pacemaker or to avoid thermal injury during multiple polypectomies, such as in patients with familial adenomatous polyposis.26
Techniques for Hot Polypectomy
The procedures for HFP and HSP are simple. The device is opened and the polyp is grasped so that no tissue is left around the device (Figures 13-2 and 13-3). This procedure can be performed by novices. However, the maneuvers should be performed with caution. Generally, all endoscopic procedures should be performed in a stable position with a straightened colonoscope without looping prior to resection. Targeted lesions should be placed at the 5 to 6 o’clock position in the endoscopic image. All movements of the endoscope or devices should not be rushed and should be performed successfully. Before cutting, the device should be pulled up and removed from the underlying muscle layer to avoid deep thermal injury when using a monopolar device. Closure of the device around the lesion should be performed at a slow pace with sufficient electrical current, and the pace should be particularly slow when using a bipolar device. After polypectomy, the treatment site should be observed carefully with magnification (if available) to confirm that no residual polyp is present at the edge of the mucosal defect and no pulsating vessel at the base of the mucosal defect. These principles are almost the same as those for cold snare polypectomy (CSP), EMR, and other endoscopic removal procedures.
Cold polypectomy (polypectomy without electrocautery) can also be categorized into 2 procedures: CFP, which uses biopsy forceps without electrocautery, and CSP, which uses an endoscopic snare without electrocautery. Originally, Tsuneoka and Uchida2 reported endoscopic polypectomy for gastric polyps without electrocautery in 1969. However, because of the belief that electrocautery can reduce the risk of bleeding, hot polypectomy has been a more popular procedure.9 In 2012, Repici et al27 demonstrated the safety of cold polypectomy in a multicenter prospective trial, which led to the reassessment of this procedure and consequently to its increasing popularity worldwide.28