the use of electrocautery during polypectomy is widely considered to be the standard of care in resecting polyps    10  mm . in practice ,
 hot  polypectomy can aid in both transecting tissue and preventing immediate bleeding through coagulation of small arterial and venous branches 1 .
electrocautery also allows for the en bloc resection of larger polyps , believed to reduce the risk of recurrent adenoma . the use of electrosurgical current during endoscopic resection , however , may be suboptimal from a safety standpoint .
for example , conventional  hot  polypectomy carries a risk of delayed bleeding 2 , possibly due to sloughing of coagulum to expose an incompletely coagulated submucosal artery .
in addition , cautery - related transmural thermal injury to the bowel wall is a major contributor to procedural adverse events 3 , manifesting in a spectrum of severity from post - polypectomy pain syndrome , to unrecognized perforation at the time of endoscopy , to frank perforation related to transection through the muscularis propria and serosa layers . while electrocautery - aided en bloc resection
theoretically may be a more effective strategy for complete resection of all polyp tissue , more than one study has shown local adenoma recurrence at a rate of up to 28  % despite this technique 4 
 5 .
cold snare polypectomy , in contrast , has been widely favored for the resection of smaller polyps since the avoidance of electrocautery clearly reduces post - polypectomy electrocoagulation syndrome , perforation , and delayed bleeding . despite these benefits ,
cold snare polypectomy for the resection of larger duodenal and colonic polyps has not been explored previously .
we hypothesized that endoscopic resection using a cold snare piecemeal technique is feasible for larger polyps . to evaluate our hypothesis , in this first proof - of - principle case series
, we assessed the technical feasibility and preliminary safety of cold snare polypectomy for larger duodenal and colonic polyps .
this study was approved by the institutional review board of the university of michigan hospital and health systems ( umhs ) .
a retrospective review was conducted of all patients who underwent polypectomy of a   10  mm adenoma from the duodenum or colon through a single endoscopist ( cp ) over a 16-month period from february 2012 to may 2013 .
the size , polyp location , morphology , resection technique , and all adjunct therapies were recorded at the time of the procedure using provation md electronic documentation ( provation medical , minneapolis , mn , united states ) .
all procedures were performed in the medical procedures unit at umhs with anesthesia support personnel .
procedures were performed using olympus equipment ( olympus america , center valley , pa , united states ) including a standard adult colonoscope , a pediatric colonoscope , a single - channel gastroscope , or a double - channel therapeutic gastroscope .
several snare manufacturers were used , including exacto snare ( us endoscopy , mentor , oh , united states ) , mini snare ( cook medical inc . ,
bloomington , in , united states ) , or hexagonal snare ( cook medical inc . ) . if en bloc resection was not feasible , the polyp was removed in a piecemeal fashion .
cold biopsy forceps were used to aid in resecting smaller pieces of residual polyp at the base and edge of the polypectomy site . before polypectomy , nearly all patients underwent a submucosal injection of 1  :  60  000 epinephrine in saline with methylene blue for the purpose of lifting the polyp . in some cases ,
a short , clear , plastic olympus cap at the tip of the scope was used to aid with resection .
patients did not undergo any form of thermal therapy including the use of  hot  forceps or argon plasma coagulation ( apc ) .
hemostatic clips were used at the discretion of the endoscopist to treat immediate bleeding . in certain cases , polyp margins were removed using radial jaw 4 biopsy forceps ( boston scientific , natick , ma , united states ) . in some cases ,
mucosa near the polyp was tattooed with spot ( gi supply , camp hill , pa , united states ) for future reference .
all patients were observed in the recovery unit following their procedure until discharge criteria were met .
abstracted data included patient demographics , american society of anesthesiologists class score , and procedure indication .
recorded polyp characteristics included type , size , location , number , and the use of forceps in addition to snare .
outcomes assessed for the purpose of this study included adverse events such as delayed post - procedural bleeding and perforation .
post - procedural assessment was conducted by chart review of the university of michigan hospital careweb and michart electronic medical records systems .
presence of a post - procedural adverse event was defined as hospitalization within 2 weeks of index endoscopy for gastrointestinal bleeding or abdominal pain based on umhs admission records or telephone records . in cases where no follow - up ( clinic visit or telephone follow - up ) was available within 3 months of the procedure , patients were contacted by telephone .
between 24 august 2011 and 29 april 2013 , 10  mm or larger duodenal polyps ( fig . 
1  a ) were removed from 15 patients by a single endoscopist ( cp ) .
the average size of the polyps removed was 24  mm with a range of 10    60  mm in largest dimension , with the 60-mm polyp being fully circumferential . in 14 patients , a submucosal injection of 1:60 000 epinephrine in saline combined with methylene blue for lifting
cold biopsy forceps were utilized for clean - up of polypoid tissue around snared edges ( table 1 ) . in two patients ,
each polyp was found to be adenomatous on histology . 
 before cold snare piecemeal resection of a large duodenal polyp . 
m , male ; f , female ; y , yes ; n , no ; n / a , data not available .
follow - up was available in 13 patients ( 
 table 1 
 ) . within 2 weeks following the procedures ,
only one patient was hospitalized at an outside facility with gastrointestinal blood loss and bowel incontinence ( table 2 ) .
oozing from the base of the polypectomy site was noted at the time of the follow - up endoscopy and four hemostatic clips were placed with cessation of bleeding .
the patient had been chronically anti - coagulated with warfarin for a bioprosthetic porcine aortic valve .
anti - coagulation was held for 5 days before the index procedure without enoxaparin bridging .
a repeat endoscopy was not required at the other facility and the patient was discharged without further adverse events .
otherwise , there were no adverse events in the remainder of the cohort , including no perforations and no post - polypectomy syndrome .
between 27 february 2012 and 30 may 2013 , a total of 15 patients underwent resection of at least one colonic polyp   10  mm ( fig . 
the average size of the polyps removed was 20  mm with a range of 10    45  mm in the largest dimension .
all polyps were removed using a cold snare . in all 15 patients , a submucosal injection of 1  :  60  000 epinephrine in saline combined with methylene blue for lifting was performed ( fig . 
cold biopsy forceps were utilized for clean - up of polypoid tissue around snared edges ( table 3 ) .
each polyp was found to be adenomatous on histology . 
 before cold snare piecemeal resection of a large colonic polyp .
m , male ; f , female ; y , yes ; n , no ; n / a , data not available .
follow - up was available in 12 patients ( table 3 ) . within 2 weeks following the procedures ,
only one patient required a hospital visit for a suspected procedure - related adverse event ( table 2 ) .
the patient presented to an outside hospital with right lower quadrant abdominal pain 1 day after resection of a 20-mm polyp from the appendiceal orifice .
a computed tomography scan revealed no evidence of perforation or inflammatory changes and the patient was discharged home directly from the emergency department ( ed ) without intervention outside of symptom management with narcotic analgesia during the ed encounter .
there were no perforations , no post - polypectomy syndrome , and no significant delayed bleeding requiring transfusions or repeat procedures . during follow - up
telephone calls , three patients reported a small amount of hematochezia occurring within 24 hours following their polyp resection .
their bleeding resolved without intervention and they did not suffer any further adverse events . no other patients with follow - up suffered any procedure - related adverse events .
between 24 august 2011 and 29 april 2013 , 10  mm or larger duodenal polyps ( fig . 
1  a ) were removed from 15 patients by a single endoscopist ( cp ) .
the average size of the polyps removed was 24  mm with a range of 10    60  mm in largest dimension , with the 60-mm polyp being fully circumferential . in 14 patients , a submucosal injection of 1:60 000 epinephrine in saline combined with methylene blue for lifting
cold biopsy forceps were utilized for clean - up of polypoid tissue around snared edges ( table 1 ) . in two patients ,
each polyp was found to be adenomatous on histology . 
 before cold snare piecemeal resection of a large duodenal polyp . 
m , male ; f , female ; y , yes ; n , no ; n / a , data not available .
follow - up was available in 13 patients ( 
 table 1 
 ) . within 2 weeks following the procedures ,
only one patient was hospitalized at an outside facility with gastrointestinal blood loss and bowel incontinence ( table 2 ) .
oozing from the base of the polypectomy site was noted at the time of the follow - up endoscopy and four hemostatic clips were placed with cessation of bleeding .
the patient had been chronically anti - coagulated with warfarin for a bioprosthetic porcine aortic valve .
anti - coagulation was held for 5 days before the index procedure without enoxaparin bridging .
a repeat endoscopy was not required at the other facility and the patient was discharged without further adverse events .
otherwise , there were no adverse events in the remainder of the cohort , including no perforations and no post - polypectomy syndrome .
between 27 february 2012 and 30 may 2013 , a total of 15 patients underwent resection of at least one colonic polyp   10  mm ( fig . 
the average size of the polyps removed was 20  mm with a range of 10    45  mm in the largest dimension .
all polyps were removed using a cold snare . in all 15 patients , a submucosal injection of 1  :  60  000 epinephrine in saline combined with methylene blue for lifting was performed ( fig . 
cold biopsy forceps were utilized for clean - up of polypoid tissue around snared edges ( table 3 ) .
each polyp was found to be adenomatous on histology . 
 before cold snare piecemeal resection of a large colonic polyp .
m , male ; f , female ; y , yes ; n , no ; n / a , data not available .
follow - up was available in 12 patients ( table 3 ) . within 2 weeks following the procedures ,
only one patient required a hospital visit for a suspected procedure - related adverse event ( table 2 ) .
the patient presented to an outside hospital with right lower quadrant abdominal pain 1 day after resection of a 20-mm polyp from the appendiceal orifice .
a computed tomography scan revealed no evidence of perforation or inflammatory changes and the patient was discharged home directly from the emergency department ( ed ) without intervention outside of symptom management with narcotic analgesia during the ed encounter .
there were no perforations , no post - polypectomy syndrome , and no significant delayed bleeding requiring transfusions or repeat procedures . during follow - up
telephone calls , three patients reported a small amount of hematochezia occurring within 24 hours following their polyp resection .
this case series is the first to demonstrate that cold snare polypectomy for large duodenal and colonic polyps is technically feasible and may have a favorable safety profile compared to standard electrocautery - based endoscopic resection .  
avoidance of electrocautery provides the benefit of eliminating any risk of post - polypectomy electrocoagulation syndrome . a recent paper by levin et al .
6 suggests that the incidence of post - polypectomy electrocoagulation syndrome is not particularly high with six cases out of 11  000 colonoscopies with biopsy .
other studies , however , have suggested a higher rate with the syndrome occurring in close to 1  % of patients 7 . while post - polypectomy electrocoagulation syndrome resolves without surgery , it often necessitates hospitalization for imaging , pain control , and supportive management .  
studies have suggested that cold snare polypectomies may not confer any added risk of perforation 8 . as most polypectomies are aimed at eradicating adenomatous tissue rather than cancer ,
based on our experience in this series , it is doubtful that it is even technically possible to cut through the muscularis propria in normal bowel without the use of cautery .
there are a number of other reasons why it may be safer to avoid heat in the removal of large colonic and duodenal polyps .
larger arterial branches within the bowel wall are difficult to transect without heated snare loops ; the use of cold snares may markedly reduce or eliminate the risk of large arterial vessel compromise .
immediate bleeding due to cold snare polypectomy is often the result of small capillary bleeding and venous oozing rather than larger arterial bleeding which    in the absence of anticoagulation , antiplatelet therapy or inherent coagulopathy   
resolves spontaneously in most , if not all , cases . in the reported series ,
all patients received dilute epinephrine in the injectate , which was added to maintain a clean field by minimizing capillary oozing during polypectomy .
however , it is unclear if this is necessary as the lift fluid itself may provide adequate tamponade of smaller capillary vessels
.   the effect of cautery and coagulation may provide the endoscopist with a false sense of security by reducing immediate bleeding , but then ultimately promotes the risk of more significant delayed bleeding from sloughing coagulated eschar .
this sloughing eschar may occur 5    21 days after the initial polypectomy . with cold snare polypectomies ,
coagulated eschar formation is eliminated , and , thus , delayed bleeding may not be a significant risk . in our series ,
delayed bleeding did not occur in any patients who underwent colonic polypectomy and who had follow - up , and only occurred in one of the duodenal polypectomy patients ; this patient was on warfarin .
an added benefit of cold snare polypectomy may be that , if delayed bleeding were confidently eliminated , there would be no need for prophylactic hemostatic clip placement , a costly and time - consuming intervention .
none of the colonic polypectomy cases in this series received prophylactic clipping , and only two of the duodenal polypectomy cases required clipping to manage immediate oozing . by reducing or eliminating delayed bleeding , not only would the morbidity and potential mortality to the patient be reduced , but there would also be the financial benefit of avoiding costly hospitalizations , blood transfusions , and repeat endoscopies or colonoscopies or even interventional radiology procedures .
cautery has historically also been viewed as a useful tool in preventing polyp recurrence . in theory ,
cautery from hot snare or apc could destroy any remaining polyp tissue that was not resected , thus preventing recurrence .
however , a recent study by mannath et al . 9 , which specifically looked at resection of colonic adenomas   1  cm , showed that the use of apc did not affect the recurrence rates after a piecemeal polyp resection . in this study ,
care was taken to excise wide margins of normal tissue around the polypectomy site to ensure the completeness of resection .
however , if pieces are not taken in an overlapping manner , there could be residual polyp tissue at the base of the resection .
this was part of the reason why we used cold forceps , to clean up any suspect areas at the base as well as the periphery of the polypectomy .
further study is needed to determine the relative rate of residual polyp tissue with this method .
there are several techniques that facilitate a successful snare polypectomy including a robust submucosal fluid injection , the use of blue dye in the injectate , and the use of braided snares .
the submucosal injection and lift itself is of particular value in the resection of large polyps , especially using the cold snare polypectomy technique we describe .
a lack of lift , for instance , can signify malignant invasion deeper than the submucosal layer 10 which would serve as a relative contraindication to an endoscopic resection .
it appears that the lift also helps to  loosen - up  the submucosa making it easier to transect the submucosal layer , and particularly easier to resect wide lateral margins of tissue .
the dye helps to differentiate between residual polyp at the base or margins , the submucosa , and normal intestinal mucosa .
our experience has also shown that the exacto snare , a thin braided snare , smaller than other available mini snares , can be a very useful tool in piecemeal resection of polyps .
it tends to work well for sections of tissue sized up to 1.5  cm .
sections of tissue larger than 1.5  cm tend to require more of a  sawing 
action with the exacto snare and may be difficult to remove en bloc without heat .
it appears that when it is used on larger pieces of tissue , it bunches up the submucosal layer ; this makes it more difficult to cut through and can even make it somewhat difficult to discern a stump of bunched - up submucosa from residual mucosal polyp after resection .
therefore , we have found that limiting the size of individual resected pieces helps in producing a quicker , simpler , and cleaner resection . while , in theory , en bloc resection is felt to achieve a more complete lesion resection 11 
 12
, it is unclear whether en bloc resection in adenomas , rather than cancer , is truly superior to piecemeal resection in prevention of residual or recurrent adenoma 10 , and ultimately , from an outcomes perspective , the primary goal in these patients is complete polyp removal with an adequate margin .
we have used large capacity forceps and the exacto snare to widely resect the lateral margins of the polypectomy site to ensure complete adenoma removal ; we also take care to resect overlapping sections of polyp tissue and carefully examine the base of the resection to ensure there are no islands of residual adenoma .
it should also be noted that , due to technical limitations , the larger a polyp is , particularly >  15    20  mm , the more likely it is to be resected in piecemeal fashion anyway , and this may influence the incidence of residual adenomas .
currently , american society for gastrointestinal endoscopy ( asge ) guidelines state that any patient with piecemeal removal of a sessile adenoma should have a repeat colonoscopy in 2 to 6 months to verify complete removal 13 regardless of whether heat is used or not .  
lastly , the use of dye such as indigo carmine or methylene blue has also been useful in aiding resection of polyps .
the dyes can stain small intestinal , colonic , or metaplastic intestinal cells through active cellular absorption 14 .
consequently , dye use can be helpful in visualizing polyp margins and residual polyp tissue during resection , which aids in differentiating between residual polyp at the base or margins , the submucosa layer ( stained blue ) , and normal intestinal mucosa .
our series is the first to report the use of piecemeal cold snare for duodenal and colonic polyps   1  cm in size .
we had no perforations , no post - polypectomy syndrome , and only one delayed bleeding episode in a patient on warfarin .
while this is encouraging , comparative trials are required to determine whether cold snare resection of duodenal and colonic adenomas truly reduces the risk of bleeding and perforation .
further studies could also shed light on the efficacy of cold snare compared to heat in producing a complete and durable polypectomy . while our results show promise in the utility of cold snare resection for larger duodenal and colonic polyps , we are aware that our series has several important limitations . as a pilot series , our sample size ( n  =  30 ) was limited , precluding robust statistical analysis .
our lack of prospective long - term follow - up raises the possibility of underreporting complications . in this retrospective case series
, we lacked critical data on the adenoma recurrence rates in piecemeal cold snare polypectomy .
these data are crucial to assess the safety and efficacy of cold snare polypectomy in large ( >  10  mm ) polyps and our pilot study was not designed or powered to compare adenoma recurrence rates of cold snare versus hot snare resection of large polyps .
if cold snare endoscopic resection is found to be as efficacious as , and safer than , hot snare , it will become the preferred approach for resection of larger polyps .
in addition to the cost savings associated with reduced adverse events , it may obviate the cost and time necessary for the placement of prophylactic hemostatic clips .
physicians performing cold snare resections may also be more comfortable with the idea of fewer adverse events , which , in turn , may reduce the number of referrals to large academic centers for complex polypectomies . given the potential for significant healthcare - related benefits , further trials evaluating the efficacy of cold snare polypectomy and comparing cold snare polypectomy to hot snare polypectomy should be strongly considered .
 
 background : endoscopic removal of duodenal and colorectal adenomas is currently considered to be the standard of care for prevention of adenocarcinoma . 
 the use of cautery carries a risk of delayed bleeding , post - polypectomy syndrome , and perforation . 
 we examined the safety and feasibility of removing colonic and duodenal polyps   1  cm using a piecemeal cold snare polypectomy technique . 
 
 patients : the study included 15 patients with duodenal polyps   1  cm and 15 patients with colonic polyps   1  cm . 
 main outcome measurements : bleeding , perforation , abdominal pain , or hospitalization occurring within 2 weeks of polypectomy . 
 results : between 24 august 2011 and 29 april 2013 , 15 patients had removal of duodenal polyps   1  cm . 
 mean patient age was 64 years and 9/15 patients were male . 
 the mean polyp size was 24  mm ( 10    60  mm ) . 
 all polyps were removed with a cold snare and some required cold biopsy forceps . 
 one patient required hospitalization for gastrointestinal blood loss 7 days post - polypectomy ; this patient was using coumadin . between 27 february 2012 and 30 may 2013 , 15 patients underwent resection of a   1  cm colonic polyp .  
 mean patient age was 68 years and 9/15 were male . 
 the mean polyp size was 20  mm ( 10    45  mm ) . 
 all polyps were primarily removed with a cold snare . 
 none of the patients required hemostatic clips for control of immediate bleeding . 
 one patient presented to the emergency department with abdominal pain 1 day after initial endoscopy . 
 ct scan showed no abnormalities and the patient was discharged . 
 
 conclusions : cold snare polypectomy for large duodenal and colonic polyps is technically feasible and may have a favorable safety profile compared to standard electrocautery - based endoscopic resection . 
 comparative trials are required to determine the relative safety and efficacy of cold snare techniques for complete and durable resection of large polyps compared to standard hot snare methods . 
Introduction
Methods
Results
Duodenal polyps
Colonic polyps
Discussion