Endoscopic mucosal resection and endoscopic submucosal dissection

Succinylated gelatin substantially increases en bloc resection size in colonic EMR: a randomized, blinded trial in a porcine model

BACKGROUND

Succinylated gelatin (SG) is an inexpensive colloid that may combine ease of use with the advantages of a colloid to potentially increase EMR specimen size, leading to a higher rate of en bloc resection.

OBJECTIVE

To evaluate the safety, efficacy, and impact on EMR specimen size of SG as a submucosal (s.m.) injectant in comparison with normal saline solution (NS).

DESIGN

Randomized, blinded, controlled trial conducted with Animal Ethics Committee approval.

SETTING

Academic hospital.

SUBJECTS

Ten swine.

INTERVENTIONS

Sixty EMRs (30 using SG vs 30 using NS as 3 paired experiments per animal) of the largest possible en bloc snare resection of normal colonic mucosa after s.m. injection of a fixed volume of either SG or NS.

MAIN OUTCOME MEASUREMENTS

EMR specimen size, duration of s.m. cushion, duration of procedure, ratio of vertical elevation to lateral spread of injectant, ease of resection, adverse effects, perforation, histopathology of EMR sites in colectomy specimens at necropsy (for inflammatory cell content, depth of ulceration, and vascular or ischemic changes).

RESULTS

The mean subject weight was 53 kg. The mean EMR specimen dimensions and surface area were significantly larger with SG (length 37 vs 31 mm, P = .031; width 32 vs 26 mm, P = .022; surface area 9.5 cm(2) vs 6.7 cm(2), P = .044, respectively). The median s.m. cushion duration was 60 minutes with SG versus 15 minutes with NS (P = .005). The median procedure duration with SG was 2.6 minutes vs 2.5 minutes with NS (P = .515). The ratio of vertical elevation to lateral spread of injectant (mean score on a 3-point scale) was 3 with SG versus 2 with NS (P = .228). Ease of resection score (mean score on a 10-point scale) was 8 with SG versus 7 with NS (P = .216). There were no systemic adverse effects, hypersensitivity reactions, or bleeding episodes. There were 2 perforations (treated with clips) with SG and 1 with NS (P = 1.0). Blinded histopathologist assessment of necropsy colectomy specimens did not identify any significant differences between SG and NS EMR sites.

LIMITATIONS

Animal study.

CONCLUSIONS

SG is safe and results in a 42% increased surface area for en bloc EMR. Given its other favorable properties, it represents a significant step toward defining the ideal EMR solution.

Comparative performance of novel solutions for submucosal injection in porcine stomachs: An ex vivo study

BACKGROUND

Submucosal injection of normal saline (NS) is commonly used during endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) but is quickly absorbed. Sodium hyaluronate (SH) produces longer lasting mucosal elevation but is expensive.

AIMS

To evaluate the performance of novel solutions for submucosal injection in comparison with NS and SH.

METHODS

One ml of the following solutions was injected in the submucosa of fresh specimens of porcine stomachs: NaCl 0.9%, SH 0.4%, human albumin 25%, two artificial tears solutions, namely, hydroxypropyl methylcellulose (HPMC) 0.3%/dextran 70.1% and polyvinyl alcohol (PVA) 1.4%, hydroxyethyl starch (HES) 6% and polyethylene glycol (PEG) 50%. The time until the disappearance of the mucosal elevation was recorded in a blind manner.

RESULTS

The median duration of mucosal elevation was significantly longer with HPMC/dextran, PVA, HES, PEG and SH (29, 26, 38, 31.5, and 41.5min, respectively) compared with NS (12min) (p<0.05 for each comparison). There were no significant time differences between SH and HPMC/dextran, HES and PEG (p>0.05).

CONCLUSIONS

Novel viscous or hypertonic solutions for submucosal injection, perform better than normal saline and equally well as sodium hyaluronate in porcine stomachs in vitro.

Large endoscopic mucosal resection for colorectal tumors exceeding 4 cm

AIM: To evaluate the feasibility and the outcome of endoscopic mucosal resection (EMR) for large colorectal tumors exceeding 4 cm (LCRT) undergoing piecemeal resection.

METHODS: From January 2005 to April 2008, 146 digestive tumors larger than 2 cm were removed with the EMR technique in our department. Of these, 34 tumors were larger than 4 cm and piecemeal resection was carried out on 26 colorectal tumors. The mean age of the patients was 71 years. The mean follow-up duration was 12 mo.

RESULTS: LCRTs were located in the rectum, left colon, transverse colon and right colon in 58%, 15%, 4% and 23% of cases, respectively. All were sessile tumors larger than 4 cm with a mean size of 4.9 cm (4-10 cm). According to the Paris classification, 34% of the tumors were type Is, 58% type IIa, 4% type IIb and 4% type IIc. Pathological examination showed tubulous adenoma in 31%, tubulo-villous adenoma in 27%, villous adenoma in 42%, high-grade dysplasia in 38%, in situ carcinoma in 19% of the cases and mucosal carcinoma (m2) in 8% of the cases. The two cases (7.7%) of procedural bleeding that occurred were managed endoscopically and one small perforation was treated with clips. During follow-up, recurrence of the tumor occurred in three patients (12%), three of whom received endoscopic treatment.

CONCLUSION: EMR for tumors larger than 4 cm is a safe and effective procedure that could compete with endoscopic submucosal dissection, despite providing incomplete histological assessment.

Management of platelet-directed pharmacotherapy in patients with atherosclerotic coronary artery disease undergoing elective endoscopic gastrointestinal procedures

The periprocedural management of patients with atherosclerotic coronary heart disease, including those who have heart disease and those who are undergoing percutaneous coronary intervention and stent placement who might require temporary interruption of platelet-directed pharmacotherapy for the purpose of an elective endoscopic gastrointestinal procedure, is a common clinical scenario in daily practice. Herein, we summarize the available information that can be employed for making management decisions and provide general guidance for risk assessment.

Management of platelet-directed pharmacotherapy in patients with atherosclerotic coronary artery disease undergoing elective endoscopic gastrointestinal procedures

The periprocedural management of patients with atherosclerotic coronary heart disease, including those who have heart disease and those who are undergoing percutaneous coronary intervention and stent placement who might require temporary interruption of platelet-directed pharmacotherapy for the purpose of an elective endoscopic gastrointestinal procedure, is a common clinical scenario in daily practice. Herein, we summarize the available information that can be employed for making management decisions and provide general guidance for risk assessment.

Subserosal injection of hyaluronic acid may prevent perforation after endoscopic resection

AIM: To investigate the protective effect of subserosal injection of hyaluronic acid (HA) after endoscopic resection (ER) using ex vivo and in vivo studies.

METHODS: As the first examination, technical application of subserosal injection was tested 10 times using resected porcine stomachs. As the second examination, ER was applied to make six mucosal defects per stomach in three live minipigs and thermal damage was given on the proper muscle layer by using hemostatic forceps. Following the thermocoagulation, 1 mL of normal saline and HA, respectively, was injected targeting the subserosal layer in two mucosal defects each and the rest kept no injection as the control. The minipigs were recovered from the anesthesia and kept fasting until euthanasia which was carried out around 24 h after the procedures.

RESULTS: Ex vivo study revealed that complete and partial subserosal injection was possible two (20%) and four (40%) times, respectively. In vivo study revealed that no postoperative perforation occurred at any point of the thermocoagulation. Apparent retention of hyaluronic acid was identified at only two (33%) points where HA was injected.

CONCLUSION: This study failed to show preventative effects of subserosal injection of HA on postoperative perforation due to technical faults. However, this concept has a possibility to change strategy of ER with further technical innovation.

Current status of colonic endoscopic mucosal resection in the west and the interface with endoscopic submucosal dissection

Endoscopic Mucosal Resection (EMR) is now widely practised by western endoscopists to treat large sessile colonic polyps or laterally spreading tumours. Despite its widespread application, the technique of colonic EMR is not standardised. A lesion specific endoscopic treatment approach is also lacking. For lesions larger than 25mm, EMR is limited by its inability to achieve en-bloc resection. En-bloc resection has many theoretical advantages including more accurate histological assessment, reduced recurrence and potentially curative treatment for low risk submucosal invasive neoplasia particularly in patients with significant co-morbidity. Hence, Japanese endoscopists, having pioneered endoscopic submucosal dissection (ESD) in the upper gastrointestinal tract for the en-bloc resection of superficial neoplasia, now advocate the use of ESD for laterally spreading tumours of the colon greater than 25-30mm. This treatment strategy is not widely accepted or practised in the west and has its own inherent problems. The absence of suitable gastric lesions on which to develop ESD skills is also another significant barrier to the development of colonic ESD. It is also possible that modification and refinement in EMR technique may increase the size limit for colonic EMR.

Mucosal ablation of Barrett esophagus

The management of Barrett esophagus is evolving with the emergence of new endoscopic technologies. Traditionally, patients with high-grade dysplasia or cancer were referred for esophagectomy. However, with the advent of endoscopic ablative therapies for Barrett esophagus, the treatment paradigm has shifted. Patients with high-grade dysplasia and intramucosal carcinoma are increasingly offered esophagus-sparing therapies. Endoscopic ablative therapies can be categorized into tissue-acquiring and non-tissue-acquiring modalities. Visible lesions in the setting of dysplasia should be treated with a tissue-acquiring modality to stage and resect the lesion appropriately. One or more modalities may be used to eradicate the entire region of affected esophagus totally. Total eradication treats all of the at-risk epithelium and, therefore, treats any metachronous or synchronous lesions. Success of treatment may be gauged by complete remission of cancer, dysplasia, or Barrett esophagus. In addition to procedure-related complications, the risk of residual Barrett esophagus or subsquamous Barrett esophagus remains to be addressed. Endoscopic surveillance and acid suppression is still currently required after ablation.

[Anticoagulation and antiplatelet therapy, and gastrointestinal endoscopy]

Over the past decade, the application of anticoagulant and antiplatelet agents for various cardiovascular and hematologic conditions has become more widespread. These medications can decrease the risk of thromboembolic events, meanwhile may potentiate gastrointestinal bleeding. The decision to reverse anticoagulation, thereby risking thromboembolic complications, must be carefully weighted against the increased risk of bleeding when maintaining anticoagulation. Elective procedures should be delayed in patients on temporary anticoagulation therapy (e.g. those with deep vein thrombosis). For procedures considered to have a low risk of bleeding (e.g. diagnostic endoscopy and biopsy) there is no need to discontinue or adjust anticoagulation. For procedures with a higher risk of bleeding (e.g. polypectomy and biliary sphincterotomy), an individual approach is required. This approach might include stopping oral anticoagulant therapy with or without the administration of unfractionated heparin or low-molecular-weight heparin for the pre-procedure and post-procedure periods, during which the patient's international normalized ratio is in the subtherapeutic range. Antiplatelet drugs (aspirin, clopidogrel, ticlopidine) may also increase the risk of bleeding induced by gastrointestinal endoscopic procedures. There is no indication to stop the therapy before esophagogastroduodenoscopy. Discontinuation of aspirin 4-7 days (according to the cardiovascular risk) before other endoscopic procedures is recommended. When aspirin is indicated for primary prevention, it can be resumed 14 days and 10 days after polypectomy and sphincterotomy, respectively. In cases of secondary prevention, it should be resumed after 1 week.

Supplementation of endoscopic submucosal dissection with sentinel node biopsy performed by natural orifice transluminal endoscopic surgery (NOTES) (with video)

BACKGROUND

Endoscopic submucosal dissection (ESD) is proving to be effective for the resection of selected early gastric and colon cancers. Its application and appropriateness could be extended if a means of determining lymphatic dissemination without recourse to a conventional operation could be provided.

OBJECTIVE

To demonstrate the feasibility of companion sentinel node biopsy (SNB) by natural orifice transluminal endoscopic surgery (NOTES) concurrent with intraluminal ESD in both the sigmoid colon and stomach.

DESIGN

Acute porcine model.

INTERVENTION

Arbitrarily selected mucosal foci were targeted for combined NOTES-SNB and ESD in the sigmoid and stomach of 2 separate anesthetized animals. NOTES peritoneal access was obtained either transgastrically or transvaginally. A second intraluminal endoscope was passed either orally or rectally, as appropriate, to perform submucosal injection for lymphatic mapping under direct vision of the NOTES endoscope. This endoscope then identified the first-order draining (sentinel) nodes and allowed their excisional biopsy. The sigmoid was retracted by magnetic assistance as required, while torque of an intraluminal gastroscope manipulated the stomach. After retrieval of the nodes, 1-cm and 1.5-cm specimens were resected from the sigmoid and stomach, respectively, by conventional ESD. At procedure end, necropsy was performed.

RESULTS

All sentinel nodes were identified, underwent biopsy, and were retrieved intact. ESD was subsequently readily performed without complication. SNB completeness and ESD quality were confirmed postprocedure.

LIMITATIONS

Experimental model with limited sample size.

CONCLUSIONS

Although not yet appropriate for human use, this proposal merits serious consideration as a potential means of augmenting the effectiveness and appropriateness of ESD techniques for GI neoplasia.