Colonoscopic snare polypectomy: analysis of 1485 resections comparing two types of current

A comparison of depth of tissue injury caused by different modes of electrosurgical current in a pig colon model

BACKGROUND

This study compared tissue injury produced by 3 types of electrosurgical current (pure cut, coagulation, blend) and two different procedures (snare and "hot biopsy").

METHODS

Each type of electrosurgical current was passed through the colon of a live pig by means of a snare or "hot biopsy" forceps, and the depth of tissue injury was determined histologically. The high-frequency electrosurgical current was provided by a single electrosurgical generator. The peak power for each type of current was determined with an oscilloscope.

RESULTS

The depth of tissue injury caused by coagulation current was significantly greater compared with blended current (p=0.0157). The depth of injury with coagulation current also was greater than with pure cut current, (p=0.0461 in a single statistical test; significance removed by Bonferroni-Dunn correction). With the hot biopsy forceps, the depth of tissue injury was deeper compared with that produced with a snare, regardless of the diameter of the snare loop. Peak power at a setting of 30 W was 1154 W for coagulation, 90.2 W for pure cut, and 227.8 W for blend current.

CONCLUSIONS

When a high-frequency electrosurgical current device is used, use of a cutting current in the blend mode is recommended instead of coagulation current because this waveform is suitable for incision and provides effective hemostasis. Skillful technique is required for safe use of a hot biopsy forceps, because there is a significant potential for deeper tissue injury with this device.

The role of flat and depressed colorectal lesions in colorectal carcinogenesis: new insights from clinicopathological findings in high-magnification chromoscopic colonoscopy

High-magnification chromoscopic endoscopy is a new technique which has been recently introduced to the UK. This technology, initially pioneered by the Japanese in the 1980s, has changed our understanding of the pathogenesis of colorectal cancer and our subsequent therapeutic strategies aimed at the secondary prevention of cancer. Magnification colonoscopic techniques when combined with colonic chromoscopy (dye spraying of the colon) permit in vivo assessments of lesions at a magnification and resolution similar to a stereomicroscope. Furthermore, flat/depressed adenomas and cancers can be diagnosed with increasing frequency and new resection practices performed. This technique is known as endoscopic mucosal resection. As gastrointestinal endoscopists adopt these new techniques, close liaison with histopathologists is essential to provide the highest standards of diagnostic accuracy. The histopathologist also needs to be aware of the endoscopic findings when interpreting specimens and hence must understand new endoscopic terminologies and classification systems that accompany the introduction of new technologies and therapeutic techniques. This article describes the controversies relating to the flat and depressed colorectal lesion, where these new endoscopic technologies are ideally suited. It then provides a working description of high-magnification chromoscopic colonoscopy including the Japanese 'pit pattern' and morphological classification system-information which will be provided to histopathologists with specimens obtained by these new techniques. Finally, we describe the procedure of endoscopic mucosal resection, as the type and quality of specimens received for histopathological analysis will be highly influenced by these techniques.

Efficacy, safety, and clinical outcomes of endoscopic mucosal resection: a study of 101 cases

BACKGROUND

Endoscopic mucosal resection (EMR) is an alternative to surgery for removal of superficial neoplastic lesions of the GI tract. The aim of this study was to assess the safety, efficacy, and clinical outcomes of EMR.

METHODS

Data from consecutive EMR procedures performed by using suction cap-assisted and/or saline solution-assisted snare resection techniques over a 45-month period were reviewed retrospectively. EUS was performed before EMR in the majority of cases. Immediate and delayed complications were recorded. Survival was assessed in patients with carcinoma or high-grade dysplasia on final histopathology in whom EMR achieved complete resection.

RESULTS

One hundred one lesions were removed by EMR in 92 patients. Indications were adenoma (67%), high-grade dysplasia (13%), intramucosal carcinoma (11%), and lesions of uncertain histopathology (10%). Locations were esophagus 19%, stomach 14%, duodenum 27%, rectum 12%, and colon 29%. Suction cap-assisted technique was used in 26% and saline solution-assisted polypectomy in 74% of cases. Complete resection was achieved in 89%. For complete resection, 17% required more than 1 session. Post-EMR histopathology was adenoma 47%, high-grade dysplasia 13%, carcinoma 16%, carcinoid 3%, benign 19%, and low-grade dysplasia 3%. EMR resulted in upgrading of histopathologic staging to carcinoma or high-grade dysplasia in 44%. Bleeding was the only complication (early 16, delayed 6). The median cancer-free survival in patients with adenocarcinoma who underwent complete resection by EMR was 27 months (interquartile range: 17-28 months).

CONCLUSION

EMR achieves complete resection in a majority of patients but is associated with a higher risk of bleeding compared with standard polypectomy. EMR changes pathologic stage in a significant number of patients. Survival data are encouraging, but long-term follow-up studies are needed.

Colonoscopic polypectomy with cutting current: is it safe?

BACKGROUND

Coagulation and blended electrosurgical current are currently recommended for colonoscopic polypectomy, whereas pure cut current is believed to be associated with a higher risk of bleeding. However, the outcome of polypectomy performed with a cut current has not been evaluated in a large case series. Our objective was to study the incidence and nature of complications when polypectomy is performed with a pure cut current.

METHODS

Among 9555 colonoscopic examinations, polypectomy cases were retrospectively reviewed for complications. The electrosurgical current applied was always the cutting waveform.

RESULTS

Electrosurgical polypectomy using pure cut current was performed to remove 4735 lesions. Hemoclips were applied to the excision site after polypectomy to prevent bleeding in 12% of the cases. Hemorrhage occurred in 1.1% of the polypectomies (3.1% of patients). The incidence of bleeding with the different methods was snare polypectomy 0.9%, endoscopic mucosal resection 1.6%, "hot" biopsy 0.4%, and piecemeal polypectomy 7.3%. Bleeding was immediate in 66.1% of episodes and delayed in 33.9%. Patients with delayed postpolypectomy bleeding were significantly younger than those with immediate bleeding (50.5 and 64.7 years, respectively, p < 0.001). There was 1 case of transmural burn, but no perforations.

CONCLUSION

Polypectomy can be performed with pure cut current with a bleeding rate comparable to that seen with the use of coagulation or blended current, provided that hemoclip placement can be used readily. Expertise in hemoclip placement is advisable if this method of polypectomy is to be used.

Postpolypectomy lower GI bleeding: descriptive analysis

BACKGROUND

Postpolypectomy hemorrhage may warrant intensive care monitoring, transfusions, and surgery. We sought factors predicting significant bleeding requiring blood transfusion and the benefits of critical care monitoring.

METHODS

Patients with postpolypectomy bleeding between April 1989 and November 1996 were identified from a comprehensive GI bleeding database. Data included age, gender, medical history, medications, polyp characteristics, and polypectomy technique. Outcomes assessed included bleeding cessation, transfusion requirements, recurrent bleeding, length of stay, and death.

RESULTS

There were 83 patients with a median age of 73 years (range 18 to 88 years; 56 men, 27 women). Comorbid conditions were common (71.1% cardiovascular, 43.4% musculoskeletal, 14.5% hematologic, 6.0% renal). Within 3 days of presentation, 32.5% had taken aspirin, 10.8% nonsteroidal anti-inflammatory drugs, 12.0% warfarin, and 12.0% corticosteroids; and within 1 day, 10.8% intravenous heparin, 7.2% subcutaneous heparin, and 7.2% dipyridamole. Fifty-seven percent of patients were hemodynamically stable. Sessile cecal polyps greater than 2 cm in diameter bled more commonly. The median number of units transfused was equal between critical care and noncritical care patients. Using age in the logistic regression model, no other variable was predictive of transfusion. Eighty patients (96.4%) received endoscopic therapy, 1 required embolization and 2 hemicolectomy. There was no significant difference in outcomes for patients managed in an intensive care unit versus a general medical floor.

CONCLUSIONS

Postpolypectomy bleeding appears to have a predictable presentation and outcome. Advanced age seems to be predictive of transfusion requirement. Patient monitoring in an intensive care setting is not absolutely necessary.

Management of gastrointestinal bleeding induced by gastrointestinal endoscopy

Therapeutic gastrointestinal endoscopy has a much greater risk of inducing gastrointestinal hemorrhage than diagnostic endoscopy. For example, colonoscopic polypectomy has a risk of approximately 1.6% of inducing bleeding, compared with a risk of approximately 0.02% for diagnostic colonoscopy. Higher-risk procedures include colonoscopic polypectomy, endoscopic biliary sphincterotomy, endoscopic dilatation, endoscopic variceal therapy, percutaneous endoscopic gastrostomy, and endoscopic sharp foreign body retrieval. The risk of inducing hemorrhage is decreased by meticulous endoscopic technique. Hemorrhage from endoscopy may be immediate or delayed. Immediate hemorrhage should be immediately treated by endoscopic hemostatic therapy, including injection therapy, thermocoagulation, or electrocoagulation. Delayed hemorrhage generally requires repeat endoscopy for diagnosis and for therapy, using the same hemostatic techniques.

Hemoclipping for postpolypectomy and postbiopsy colonic bleeding

BACKGROUND

Obtaining colonoscopic biopsies and polypectomy can result in hemorrhage. The most effective management of this complication has not been determined. The objective of this study was to evaluate the endoscopic hemoclip in postprocedural colonic bleeding.

METHODS

Among 9555 consecutive colonoscopies, cases of postprocedural colonic bleeding (postpolypectomy and postbiopsy) requiring treatment were retrospectively reviewed. Endoscopic hemoclipping was initially attempted in each case; the rate of hemostasis after hemoclipping, use of additional hemostatic methods, and clinical outcome (need for transfusion/hospitalization) were analyzed.

RESULTS

There were 72 cases of bleeding in which treatment was required (45 immediate postpolypectomy, 18 delayed postpolypectomy and 9 postbiopsy). Endoscopic hemostasis was achieved in all cases of immediate postpolypectomy and postbiopsy bleeding and in all but one of the cases with delayed postpolypectomy bleeding. A detachable snare was used in addition to hemoclips in 3 cases of delayed postpolypectomy bleeding. There were no episodes of recurrent bleeding, deaths or need for surgery related to bleeding.

CONCLUSION

Early endoscopic management of postprocedural bleeding by hemoclipping provides hemostasis in the great majority of cases.

Prospective analysis of complications 30 days after outpatient colonoscopy

BACKGROUND

Our objective was to (1) determine whether more complications are reported by patients 30 days after outpatient colonoscopy than are discussed at our monthly morbidity and mortality conferences, (2) identify complications resulting in visits to the emergency department or physician's office or leading to hospitalization, and (3) assess which factors put patients at highest risk. A secondary goal was to determine the rate of work lost after outpatient colonoscopy.

METHODS

Trained interviewers performed standardized telephone interviews of consecutive outpatients undergoing colonoscopy at Georgetown University Hospital over a 1-year period.

RESULTS

One thousand one hundred ninety-six patients were contacted 30 days after outpatient colonoscopy and participated in our study. Twenty patients had complications that required a visit to an emergency department or physician. Ninety percent of these cases (18) were detected at 30 days, but 15% (3) were discussed at morbidity and mortality conferences. All seven complications that necessitated hospitalization were identified at 30 days, but only two were discussed at our morbidity and mortality conference. The most common complications reported by patients were abdominal discomfort (5.4%) and rectal bleeding (2.1%).

CONCLUSION

More complications are detected by means of contacting patients 30 days after outpatient colonoscopy than are discussed at our morbidity and mortality conferences.

Is virtual colonoscopy a cost-effective option to screen for colorectal cancer?

OBJECTIVE

Computed tomography (CT) or magnetic resonance (MR) colonography is a new technique that uses data generated from CT or MR imaging to create two- and three-dimensional scans of the colon. It has been advocated to become the new primary technique of screening for colorectal cancer. The economic feasibility of such recommendation, however, has not yet been evaluated.

METHODS

The cost-effectiveness of two screening strategies using CT colonography or conventional colonoscopy was compared by computer models based on a Markov process. We supposed that a hypothetical population of 100,000 subjects aged 50 yr undergoes a screening procedure every 10 yr. Suspicious findings of CT colonography are worked-up by colonoscopy. After polypectomy, colonoscopy is repeated every 3 yr until no adenomatous polyps are found.

RESULTS

Under baseline conditions, screening by CT colonography costs $24,586 per life-year saved, compared with $20,930 spent on colonoscopy screening. The incremental cost-effectiveness ratios comparing CT colonography to no screening and colonoscopy to CT colonography were $11,484 and $10,408, respectively. Screening by colonoscopy remains more cost-effective even if the sensitivity and specificity of CT colonography both rise to 100%. For the two screening procedures to become similarly cost-effective, CT colonoscopy needs to be associated with an initial compliance rate 15-20% better or procedural costs 54% less than colonoscopy.

CONCLUSIONS

To become cost-effective and be able to compete with colonoscopy in screening for colorectal cancer, CT or MR colonography would need be offered at a very low price or result in compliance rates much better than those associated with colonoscopy.

Grasping forceps assisted endoscopic resection of large pedunculated GI polypoid lesions

BACKGROUND

Endoscopic resection of pedunculated polyps with heads 1 cm or greater in diameter is technically complex. To facilitate removal of such polyps, we developed grasping forceps assisted endoscopic resection in which we use a detachable snare to prevent polypectomy-related bleeding and evaluated the usefulness and safety of the procedure.

METHODS

Ten patients with pedunculated polyps with heads 1 cm or greater in diameter were treated with this technique. A two-channel endoscope, grasping forceps, electrosurgical snare, and detachable snare are needed for the procedure.

RESULTS

All lesions were easily and safely resected. During this procedure, a two-channel endoscope with grasping forceps proved to be satisfactory for handling the detachable snare and the electrosurgical snare and for accurate recognition of the stalk under good visual control. No hemorrhage, perforation, or other complication occurred as a result of use of this new technique.

CONCLUSIONS

Grasping forceps assisted endoscopic resection of polyps with a detachable snare is an effective method for the prevention of polypectomy-associated bleeding. This technique makes it technically easier to resect large pedunculated polypoid lesions of the GI tract.

Ineffective use of a detachable snare for colonoscopic polypectomy of large polyps

BACKGROUND

Colonoscopic polypectomy of large polyps may be associated with complications such as bleeding. Use of a detachable snare may reduce the risk of bleeding. We describe several instances in which the use of such a device proved to be ineffective.

METHODS

A detachable snare was used for colonoscopic polypectomy of large polyps in 18 patients (20 polyps), also applied at the residual stalk after conventional polypectomy in 5 patients (5 polyps), and evaluated retrospectively.

RESULTS

Sixteen of the 20 polyps were pedunculated, and 4 were semi-pedunculated. In 3 of the 4 semi-pedunculated lesions, the loop slipped off after polypectomy because the lesions were cut close to the site of encirclement. Bleeding occurred in 4 cases because of transection by the loop of a thin stalk (4 mm) before polypectomy (1), slipping of the loop in a semi-pedunculated lesion (1), or insufficient tightening of the loop (2). After conventional polypectomy, we could not effectively snare the residual stalk because of flattening in 3 of the 5 lesions.

CONCLUSIONS

Use of the detachable snare for polypectomy of thin stalked or semi-pedunculated lesions may result in technical failure of this technique. The stalk should be fully encircled with the snare before polypectomy. The detachable snare is difficult to apply at the residual stalk after conventional polypectomy.

Endoscopic resection of large pedunculated colorectal polyps using a detachable snare

BACKGROUND

Colonoscopic resection of pedunculated polyps with heads 1 cm or greater in diameter is difficult because of the risk of bleeding. To minimize this complication, we used a detachable snare that allowed endoscopic ligation of the stalk of a large pedunculated polyp and evaluated its safety and effectiveness in comparison with conventional endoscopic snare polypectomy.

METHODS

Patients with pedunculated polyps with heads 1 cm or greater in diameter were randomly assigned to colonoscopic polypectomy with (N = 47) or without (N = 42) a detachable snare. Arterial pumping bleeding immediately after colonoscopic polypectomy or hematochezia resulting in a 10% or greater drop in hematocrit was defined as "bleeding."

RESULTS

No bleeding occurred during or after polypectomy with a detachable snare, but bleeding occurred significantly more frequently (five patients, 12%) without a snare. Moreover, the use of a detachable snare reduced the duration of hospitalization after polypectomy.

CONCLUSIONS

Colonoscopic polypectomy with a detachable snare may be safer than conventional polypectomy without a detachable snare for resection of large, pedunculated polyps.

Pitfalls in polypectomy: from gene to cure

Unsuspected problems are commonly encountered during colonoscopic polypectomy. This paper identifies the most frequent difficulties and describes solutions to them. One of the most important pitfalls is overlooking a lesion or tumour in the colon; this can only be solved by better training, experience and care, although it may happen in the best of hands with the most knowledgeable colonoscopist. Other pitfalls addressed include the stuck snare, use of a gastroscope for the difficult sigmoid polyp, and methods to aid discovery and retrieval of the polypectomy specimen.