Snare Selection Aaron Sinclair MD University of Kansas

Snare Selection Aaron Sinclair, MD University of Kansas School of Medicine - Wichita Department of Family and Community Medicine Wesley Family Medicine American Association of Primary Care Endoscopy President

Disclosures • I received two chipotle meals in discussing snares with Boston Scientific. • No regrets!

ESGE Guidelines 2017 • ESGE recommends against the use of cold biopsy forceps (CBF) excision. May consider in the case of a polyp sized 1 – 3 mm where cold snare polypectomy is technically difficult or not possible. (Moderate quality evidence; strong recommendation. ) • ESGE recommends cold snare polypectomy (CSP) as the preferred technique for removal of diminutive polyps (size ≤ 5 mm). (High quality evidence; strong recommendation. ) • Hot snare polypectomy (HSP) (with or without submucosal injection) for removal of sessile polyps 10 –  19 mm in size. (Low quality evidence; strong recommendation. )

ASGE Recommendations 2020 • For diminutive (<5 mm) and small (6– 9 mm) lesions recommend cold snare polypectomy to remove diminutive (<5 mm) and small (6– 9 mm) lesions due to high complete resection rates and safety profile. (Strong recommendation, high-quality evidence) • We recommend against the use of cold forceps polypectomy to remove diminutive lesions due to high rates of incomplete resection. For diminutive lesions <2 mm, if cold snare polypectomy is technically difficult, jumbo or large-capacity forceps polypectomy may be considered. (Strong recommendation, moderate-quality evidence) • Recommend against the use of hot biopsy forceps for polypectomy of diminutive and small lesions due to high incomplete resection rates, inadequate histopathologic specimens, and complication rates. (Strong recommendation, moderate-quality evidence) • Non-pedunculated (10– 19 mm) lesions: Suggest cold or hot snare polypectomy (with or without submucosal injection) to remove 10 - to 19 -mm non-pedunculated lesions. (Conditional recommendation, low-quality evidence)

Big Push To Use Cold Snares • Cold forceps resection of diminutive polyps is associated with high rates of incomplete resection. (10 -25% incomplete resection) • Hot snare polypectomy incomplete resection rates has been reported in 10% of 5– 20 mm neoplastic polyps and increases with polyp size (17% for 10– 20 mm polyps) • Hot biopsy forcep: Another prospective study involving patients with diminutive rectal adenomas found that the rate of remnant adenoma tissue after HBF polypectomy was 10. 8 %. • The Big Goal: Avoid INTERVAL Cancers! – 10 -30% of incomplete polypectomies are thought to result in interval cancers.

Cold Snares Improve Resection Rates • A recent randomized trial supports the use of a dedicated snare for cold resection. It found that incomplete resection of up to 10 mm polyps was significantly less frequent when using a dedicated cold snare compared with a standard snare (9 vs. 21%).

Smaller Snares Improve Resection Rates • Histologically complete resection rates and the frequency of complications for 175 colon polyps removed by cold snare polypectomy (CSP). • There was no significant difference in the histologically complete resection rate between endoscopic mucosal resection (EMR) and CSP. • There were also no significant differences in the frequency of complications including perforation and postoperative bleeding between EMR and CSP. • There were no significant differences in the frequency of complications between CSP using the short snare and that using the long snare. • Histological examination revealed that the complete resection rate of CSP using a short snare (61. 6%) was significantly higher than that of CSP using a long snare (44. 9%; P < 0. 05).

Cold Snares vs Conventional Snares • Cold Snare Thinner wire (0. 33 mm) 3 wires thick (1 x 3) Cuts mucosa Firmer plastic sheath Better margins (grips and holds) – Polyp tends to stay after resection – – –

Cold Snares vs Conventional Snares • Conventional Snare Thicker wire (0. 47 mm) 7 wires thick (1 x 7) Tears through mucosa Thinner plastic sheath Tends to slide especially on small and flatter polyps – Thicker wire can fling the polyp after removal – – –

Cold Snares vs Conventional Snares • Cold Snare Thinner wire (0. 33 mm) 3 wires thick (1 x 3) Cuts mucosa Firmer plastic sheath Better margins (grips and holds) – Polyp tends to stay after resection – – – • Conventional Snare Thicker wire (0. 47 mm) 7 wires thick (1 x 7) Tears through mucosa Thinner plastic sheath Tends to slide especially on small and flatter polyps – Thicker wire can fling the polyp after removal – – –

The gentle “push & cut” technique should be used for cold resection, in contrast to the “lift & cut” technique for hot snare polypectomy.

Cold Snare Technique for Diminutive Polyps Aim for 2 mm margins which is the size of the plastic catheter

Ensuring a clean base • Central tissue protrusions after cold snare resection of larger polyps can occur. Such protrusions do not contain adenoma tissue. • Polyps >6 mm typically • Tuttici 2015 study of 18 tissue specimens of the polyp stalk, no neoplasia identified.

Crescent snares Indications: – Folds and side walls – Anchor with the point and then roll it over

Hexagonal Snares Indications: – Flat polyps – Multiple polyps of varying size – EMR Features: – Memory points help with exact placement – Memory points cause it to have different shapes based on deployment – Easy to use for diminutive and small polyps

Rotatable Snares Indications: Right Sided Polyps Unable to rotate Loops in the colon

Troubleshooting Dedicated Cold Snare wire fails to cut through ensnared tissue - likely reflecting submucosal tissue entrapment. – One technique: “captured tissue was guillotined repeatedly in order to remove the polyp completely. ” – Minimize deep submucosal entrapment by maintaining insufflation during snaring and avoiding suction – Maintain full snare closure for up to 10 seconds because slow transection may occur

Troubleshooting Dedicated Cold Snare wire fails to cut through ensnared tissue - likely reflecting submucosal tissue entrapment. – Use techniques to maximize force transmission from the handle down the snare wire, and, finally if required – In a slow, controlled maneuver, partially reopen the snare to release entrapped submucosa while gently lifting the lesion away from the colon wall. – Repeated maneuvers to open and/or close the snare might compromise the rim of normal tissue

Final Thoughts 1. Cold forceps resection should be limited to small diminutive polyps (≤ 3 mm). 2. Cold snare resection may be considered as the primary resection method for polyps up to 10 mm in size. 3. A dedicate cold snare should be used for cold snare resection, particular for polyps smaller than 5 mm. 4. The gentle “push & cut” technique should be used for cold resection, in contrast to the “lift & cut” technique for hot snare polypectomy. 5. Snare wire fails to cut through ensnared tissue - likely reflecting submucosal tissue entrapment. This can be remedied with several optional techniques. 6. Newer dedicated cold snares have unique design elements that can aid in quick effective polypectomies.

References • Von Renteln D et al. Pushing the Limit: How to Get the Most Out of Cold Snares. . Am J Gastroenterol 2016; 111: 1217– 1219; doi: 10. 1038/ajg. 2016. 275; • https: //en. wikipedia. org/wiki/Therapeutic_endoscopy • Noda H et al. The Influence of Snare Size on the Utility and Safety of Cold Snare Polypectomy for the Removal of Colonic Polyps in Japanese Patients. J Clin Med Res. 2016 Sep; 8(9): 662 -6. • Li, Dazhou. Efficacy and safety of three different endoscopic methods in treatment of 6 -20 mm colorectal polyps. Scandinavian journal of gastroenterology. 03/2020 55. 3 362 -370 • https: //marlin-prod. literatumonline. com/cms/attachment/4 dc 1066 f-e 95 f 403 a-b 2 a 0 -9 ce 0 f 998 d 981/gr 2. jpg • Hewett D. Cold snare polypectomy: optimizing technique and technology (with videos) Gastrointestinal Endoscopy, 2015 -10 -01, Volume 82, Issue 4, Pages 693 -696 • https: //www. merckmanuals. com/~/media/manual/professional/images/sessi le_polyp_high. jpg? la=en&thn=0 • Kaltenbach T. Endoscopic Removal of Colorectal Lesions Recommendations by the US Multi-Society Task Force on Colorectal Cancer. GASTROINTESTINAL ENDOSCOPY Volume 91, No. 3 : 2020

References • Horiuchi et al. Prospective, randomized comparison of 2 methods of cold snare polypectomy for small colorectal polyps. PMID: 25922251. DOI: 10. 1016/j. gie. 2015. 02. 012 • https: //www. henryschein. com/us-en/images/medical/gi-endoscope 02. jpg • Tutticci et al. Characterization and significance of protrusions in the mucosal defect after cold snare polypectomy. Gastrointest Endosc . 2015 Sep; 82(3): 523 -8. • Pohl H. Standard polypectomy techniques: Choosing the right technnique. SAGES 2017. https: //www. youtube. com/watch? v=yf 4 JTe 6 mtso • https: //www. researchgate. net/profile/Misael_Uribe/publication/2825 19495/figure/fig 1/AS: 281002720153651@1444007677947/Polypsfound-during-colonoscopies-and-snare-polypectomy. png • Ferlitsch M. Colorectal polypectomy and endoscopic mucosal resection (EMR): European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline. Endoscopy. 2017 Mar; 49(3): 270 -297.