Submucosal injection solution for endoscopic resection in gastrointestinal tract: a traditional and network meta-analysis. Gastroenterol Res Pract. 2015;2015:702768. [PMID: 25705221 PMCID: PMC4326037 DOI: 10.1155/2015/702768]

Hypertonic solution as an optimal submucosal injection solution for endoscopic resection of gastrointestinal mucosal lesions: Systematic review and network meta-analysis

OBJECTIVES

Based on different physicochemical properties, common submucosal injection solutions could be classified into three categories: normal saline solution (NS), hypertonic solution (HS), and viscous solution (VS). We compared the efficacy and safety of various categories of solutions in this network meta-analysis of randomized controlled trials (RCTs) to identify the optimal submucosal injection fluid.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched for RCTs that compared the efficacy and safety of NS, HS, and VS during endoscopic resection for gastrointestinal (GI) mucosal lesions. Pairwise and network analyses were conducted to determine the ranking of different fluids.

RESULTS

Thirteen RCTs were included in the final analysis with 1637 patients (1639 lesions). HS outperformed NS in rates of en bloc (pooled relative risk [RR] 1.50; 95% confidence interval [CI] 1.10-1.90), overall bleeding (pooled odds ratio [OR] 0.33; 95% CI 0.10-0.88; lesions >10 mm OR 4.65 × 10-2; 95% CI 1.10 × 10-3-0.46), and intraoperative bleeding (lesions >10 mm OR 7.10 × 10-6; 95% CI 4.30 × 10-18-0.26). HS showed the highest probability of ranking first in each outcome except for the volume of injection. Although VS was superior to NS in rates of en bloc, overall, and intraoperative bleeding in the lesions >10 mm subgroup, and required less fluid in pooled analysis, it ranked last in cost of submucosal injection solution.

CONCLUSIONS

Both HS and VS were superior to NS in comparisons of efficacy and safety. Considering the better performance and potentially low cost, HS might be an optimal choice during gastrointestinal endoscopic resection, especially for colorectal endoscopic mucosal resection.

Novel endoscopic management of gastroenterological anastomosis leakage by injecting gel-forming solutions: an experimental animal study

BACKGROUND

Anastomotic leakage (AL) after gastrointestinal surgery remains a challenging complication that requires surgical or non-surgical treatment. Although various therapeutic endoscopic techniques are available, no definitive interventions exist. We developed a therapeutic endoscopic submucosal injection method using novel gel-forming mixed solutions to close AL and evaluated the elasticity of the developed hydrogel. The safety and efficacy of the injection method were explored in porcine AL models.

METHODS

We developed a novel gel-forming solution, and the formed gel lasted approximately one week within the gastrointestinal wall. An indentation test evaluated the elasticity of the novel hydrogel. After the confirmation of AL on porcine anterior gastric walls, sodium alginate was endoscopically injected into the submucosal layer around the leakage site circularly, followed by a calcium lactate/chitosan-based solution. After that, the outcomes data were collected, and histopathological effectiveness was evaluated.

RESULTS

The increased sodium alginate elasticity with the addition of calcium lactate/chitosan-based solution facilitated long-lasting gel formation. Four pigs with AL underwent this intervention consecutively. Each endoscopic injection was completed in less than 5 min. No significant complications were observed for 3 weeks after the intervention. All AL sites were macroscopically healed. Histopathologic findings at 3 weeks showed that the wall defect was filled with collagen fibers that had grown around the site of the muscle layer tear. No tissue necrosis was observed.

CONCLUSION

This preclinical study demonstrated that the therapeutic injection method for gastroenterological AL using gel-forming solutions could be an alternative endoscopic treatment, especially in patients with severe conditions or comorbidities. The optimal target of this treatment is small size and early AL without poor blood flow or intense hypertrophic scar lesions.

Bulking agents in gastrointestinal endoscopy: present applications and future advances

PURPOSE OF REVIEW

Bulking agents are inert materials injected into an organ to affect the physical properties of the organ for a therapeutic purpose. Various agents have been developed to aid in the treatment of diseases like gastroesophageal reflux disease (GERD), fecal incontinence, obesity, malignancy, hemostasis, and tissue dissection. Here, we review the state of the art in bulking agents in gastrointestinal endoscopy, past failures, current limitations, and where we see the field heading in the future.

RECENT FINDINGS

Though bulking agents have been trialed for various different gastrointestinal diseases, there are currently limited uses in gastrointestinal endoscopy. Though various agents have been trialed for GERD, numerous complications and adverse events have limited its current use. However, for the treatment of fecal incontinence endoscopic bulking agent therapy is a reasonable option. Though in early stages of exploration, bulking agent therapy for enteric protection from radiotherapy may be a promising tool to improve treatment of pancreatic cancer. Bulking agents for tissue dissection have substantially improved lifting agents and complex polyp removal. Bulking agent therapy has not really been explored for endoscopic bariatric therapy or hemostasis but may be a fruitful area for exploration in the future.

SUMMARY

Bulking agent therapy has been trialed for various gastrointestinal diseases with mixed success. There is currently a therapeutic roll in the endoscopic management of fecal incontinence and tissue dissection. A future role in the treatment of GERD, obesity, malignancy, and hemostasis seem feasible.

Randomized controlled trial investigating use of submucosal injection of EverLift™ in rates of complete resection of non-pedunculated 4-9 mm polyps

INTRODUCTION

Currently, cold snare polypectomy (CSP) without submucosal injection is recommended for removing polyps < 10 mm. Use of viscous submucosal agents has not been previously evaluated in CSP. We investigate the potential role of EverLift™ (GI Supply, Pennsylvania) in CSP.

METHODS

The study is a single-center prospective randomized non-inferiority clinical trial evaluating CSP of non-pedunculated 4-9 mm polyps, with or without submucosal injection of EverLift™. Patients 18-80 years of age presenting for colonoscopy were recruited. Eligible polyps underwent block randomization to CSP with or without EverLift™. Following CSP, two biopsies were performed at the CSP site margin. The primary non-inferiority outcome was complete resection rate, defined by absence of residual polyp in the margin biopsies (non-inferiority margin -10%).

RESULTS

A total of 291 eligible polyps underwent CSP, with 142 removed using EverLift™. There was similar polyp size and distribution of pathology between the two groups. Overall, there was a low rate of positive margins with (1.4%) or without submucosal injection (2.8%), with no significant difference in complete resection (difference 1.28%, 95% CI: -2.66 to 5.42%), demonstrating non-inferiority of EverLift™ injection. Use of EverLift™ significantly increased CSP time (109.8 vs 38.8 s, p < 0.0001) and frequency of use of hemostatic clips (13.4 vs 3.6%, p = 0.002).

CONCLUSION

Submucosal injection of EverLift™ was non-inferior to CSP of 4-9 mm polyps without injection and increased time for resection as well as use of hemostatic clips to control acute bleeding. Our results suggest that polypectomy of 4-9 mm polyps can be safely performed without submucosal injection of EverLift™.

Submucosal lifting agent ORISE gel causes extensive foreign body granuloma post endoscopic resection

BACKGROUND

Submucosal injection of lifting solution is often performed to facilitate endoscopic mucosal resection or endoscopic submucosal dissection. ORISE^TM gel is a synthetic solution recently approved by the US Food and Drug Administration (FDA) in 2018 for use as submucosal lifting solution for endoscopic resection procedures and has gained popularity for its convenient pre-filled syringe. However, here the present two cases show that ORISE^TM gel induces marked foreign body giant cell granulomatous reaction in the submucosa and muscularis propria following endoscopic resection.

METHODS AND RESULTS

A 73-year-old female underwent laparoscopic right colectomy after her initial endoscopic polypectomy of a hyperplastic polyp, and a 78-year-old male had partial gastrectomy following endoscopic mucosal resection of an invasive adenocarcinoma. Both patients had submucosal injection of ORISE^TM gel during endoscopic procedures, and the surgical resection specimens showed ORISE^TM gel deposition and extensive foreign body giant cell granulomatous reaction in the submucosa and muscularis propria.

CONCLUSION

These cases raise the awareness that ORISE^TM gel stimulates extensive foreign body reaction at the injection site, and the further consequence is still unclear.

Efficacy and safety of a novel submucosal injection solution for endoscopic resection in porcine models

OBJECTIVE

A submucosal injection is usually required to improve the efficacy and safety of endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR). This study aimed to evaluate the performance of 3.3% sodium carboxymethyl starch (Na-CMS) solution, a novel submucosal injection solution, for ESD and EMR.

METHODS

Na-CMS, normal saline (NS) and two commercially available agents (sigMAVisc and Eleview) were injected into the esophageal submucosa of randomly grouped pigs. The level of submucosal elevation was examined. Subsequently, ESD or EMR procedures using 3.3% Na-CMS or NS as submucosal injections were performed in the gastrointestinal tract of the pigs.

RESULTS

Submucosal elevation was significantly higher and more sustained in the 3.3% Na-CMS group than in the controls (P < 0.05). The volume required for ESD or EMR was significantly lower in the 3.3% Na-CMS group than in the NS group (ESD: 12.21 ± 4.09 mL vs 28.25 ± 8.02 mL, P < 0.001; EMR: 3.99 ± 1.98 mL vs 7.15 ± 3.67 mL, P = 0.001). The ESD resection time was significantly shorter in the 3.3% Na-CMS group than in the NS group (16.58 ± 7.30 min vs 25.29 ± 11.89 min, P = 0.004). Hemorrhage after ESD in the 3.3% Na-CMS group was less severe than that in the NS group (P = 0.006).

CONCLUSION

3.3% Na-CMS is an effective, safe and low-cost submucosal injection solution and holds promise as preferable agent for submucosal injection in ESD and EMR procedures.

Computational Fluid Dynamics (CFD)-Based Optimization of Injection Process during Endoscopic Mucosal Therapy

Creation of a submucosal plane to separate the lesion from the deeper muscle layer in gastrointestinal tract is an integral and essential part of endoscopic resection therapies such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Thereby, an optimized submucosal injection technique is required to ensure a successful process. In this study, the computational fluid dynamics (CFD) technique is employed as a foundational step towards the development of a framework that can provide useful directions to optimize the injection process. Three different lifting agents, including Glycerol, Eleview^®, and ORISE^® gel have been used for this study. The role of different injection angles, injection dynamics, and effect of temperature are studied to understand the lifting characteristic of each agent. The study shows that Eleview^® provides the highest lifting effect, including the initial injection period. To evaluate the impact of the injection process, two cases are simulated, termed static injection and dynamic injection. Under static injection, the injection angle is investigated from lower to higher angles of injection. In the dynamic injection, two cases are modulated, where a continuous change of injection angle from lower to higher degrees (denoted as clockwise) and vice-versa in the anti-clockwise direction are investigated. Increased lifting characteristics are observed at decreasing/lower angle of injection. Further, the correlation between temperature of the lifting agents and their lifting characteristics is investigated.

Characterization of Novel Injectable Lifting Agents Used in Colonic Polyp Removal: An Emerging Amyloid Mimic

Colon polypectomy can require an injection of a submucosal lifting agent to fully visualize and completely remove the polyp. To the best of our knowledge, this is the largest morphologic series on the novel lifting agents Eleview and Orise. The study consisted of 1 polypectomy and 8 colon resections from 9 patients: 6 women, 3 men (mean age=64 y); Orise=6, Eleview=3; the median time interval between injection and resection=16 weeks. Pathologic diagnoses of the polyps included tubular adenoma (n=4), tubulovillous adenoma (n=4), and sessile serrated adenoma/polyp (n=1). We report that a histologically processed Orise aliquot from the manufacturer showed similar histology to that seen in the specimens from patients with confirmed Orise injection. The morphology of the agents in the patient specimens changed with time status postinjection: immediate resection of the lifting agent showed basophilic, amorphous, and bubbly-extracellular material with prominent hemorrhage, and resection ∼3 months after lifting agent injection showed prominent hyalinized, pink-amorphous ribbons and globules with a foreign body giant cell reaction and fibrosis. The epicenter of the lifting agents was in the submucosa, and the agents were neither refractile nor polarizable. Because of the morphologic overlap with amyloid, 5 cases were stained with Congo Red, and all cases were negative. In conclusion, awareness of the morphology of these new lifting agents is important for accurate diagnosis and to avoid the diagnostic pitfall of amyloid. These lesions can be definitively distinguished from amyloid by their nonreactivity on a Congo Red and familiarity with their characteristic clinicopathologic presentation.

Endoscopic submucosal dissection: an update on tools and accessories

Endoscopic submucosal dissection (ESD) is a minimally invasive therapeutic procedure to remove larger polyps or early non-metastatic lesions. It has long been used in Asia, but is now fast growing in popularity in the West. There are multiple challenges faced by ESD practitioners. While the practice of ESD in gastric lesions is relatively well established, the oesophagus with its narrow lumen and challenging workspace, and the colon with its tortuous course and folds are more challenging frontiers. The nature of performing a procedure endoscopically means that conventional methods offer no mechanism for providing counter-traction while performing dissection, impeding visibility and increasing the rate of complications. There are a multitude of tools available to those performing ESD for the different stages of the procedure. This article reviews the accessories currently used in regular ESD practice including the knives used to cut and dissect lesions, the cap and hood devices used to improve visibility and safety, injection fluids to lift the submucosal plane, haemostatic devices, generators, and finally, emerging traction apparatus. There is some evidence behind the use of these tools, however, ESD remains the domain of a small number of practitioners and the practice relies heavily on expert experience. Evolution of the ESD toolbox will make the procedure more accessible to more endoscopists, which in turn will drive the development of a more substantial evidence base to evaluate efficacy and safety of the multitude of tools.

Comparative study of electrical and rheological properties of different solutions used in endoscopic mucosal resection

BACKGROUND AND AIM

The study of electrical and rheological properties of solutions to carry out endoscopic resection procedures could determinate the best candidate. An ex vivo study with porcine stomachs was conducted to analyze electrical resistivity (R) and rheological properties (temperature, viscosity, height and lasting of the cushion) of different substances used in these techniques.

METHODS

Tested solutions were: 0.9% saline (S), platelet-rich plasma (PRP), Gliceol (GC), hyaluronic acid 2% (HA), Pluronic-F127 20% (PL), saline with 10% glucose (GS), Gelaspan (GP), Covergel-BiBio (TB) and PRP with TB (PRP+TB). Measurements of electrical and rheological properties were done at 0, 15, 30, 45 and 60 min after submucosal injection.

RESULTS

Solutions showed a wide variability of transepithelial R after submucosal injection. Substances able to maintain the highest R 60 min postinjection were TB (7 × 10⁴ Ω), HA (7 × 10⁴ Ω) and PL (7 × 10⁴ Ω). Protective solutions against deep thermal injury (Tª lower than 60°C) were PL (47.6°C), TB (55°C) and HA (56.63°C). Shortest time to carry out resections were observed with GC (17.66″), PRP (20.3″) and GS (23.45″). Solutions with less cushion decrease (<25%) after 60 min were TB (11.74%), PL (18.63%) and PRP (22.12%).

CONCLUSIONS

Covergel-BiBio, PL and HA were the best solutions with long-term protective effects (transepithelial R, lower thermal injury and less cushion decrease). Solutions with quicker resection time were GC, PRP and GS.

Solutions for submucosal injection: What to choose and how to do it

During the past decades, endoscopic resection techniques have gradually improved and gained more importance for the management of premalignant lesions and early cancers. These endoscopic resection techniques can be divided in 3 major groups: snare polipectomy, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). The use of submucosal injection is essential for the majority of EMR techniques and is an integral part of ESD, whereas during polipectomy it is not crucial in most cases except to prevent bleeding in large polyps and/or those with large stalks as an alternative to mechanical methods. Injection provides a lifting up effect of the lesion separating it from the muscular layer, thereby reducing thermal injury and the risk of perforation and bleeding while also facilitating en-bloc resection by improving technical feasibility. With this work, we aim to review the most common endoscopic resection techniques and the importance of submucosal injection in each one of them. For that, we present some of the most commonly used submucosal injection solutions, taking into account their advantages and disadvantages. We also discuss, based on current recommendations and our own experience, how and when to preform submucosal injection, depending on lesions features and endoscopic resection technique that´s being used, to assure complete resection and to prevent associated adverse events. Finally, we also present and discuss some new proposed submucosal injection solutions, endoscopic resection techniques and devices that may have a major impact on the future of therapeutic endoscopy.

Thermoresponsive aerification and tissue vacuolization for facilitating endoscopic submucosal resection

BACKGROUND AND AIMS

Mucosal lifting and its persistence are critical for maintaining the operational space and preventing perforation in endoscopic operation. Although numerous agents have been investigated, optimization is still required for improving their clinical performance. In the present study, we proposed a novel concept of thermoresponsive aerification and tissue vacuolization for submucosal injection.

METHODS

Lifting performance and operational condition were first evaluated in porcine stomachs in vitro and rabbits in vivo. Dodecafluoropentane (DDFP) injection dosage, lifting persistency and operational assistance were quantitatively recorded. Gross and histological pathology were also analyzed to identify DDFP acute toxicity and long-term safety. The endoscopic submucosal dissection (ESD) procedure with DDFP was carried out on pigs in vivo to confirm its operational feasibility, efficacy, and safety.

RESULTS

Dodecafluoropentane aerification could achieve better mucosal lift with lower dosage (1% of normal saline dosage). Thermoresponsive DDFP aerification could provide continuous replenishment and longer persistence. Meanwhile, its tissue vacuolization effect significantly facilitated submucosal tissue dissection in in vitro study. Similar performance was verified in vivo. The particular vacuole-like submucosal structure was seen after DDFP onset, which also promoted reepithelization and wound healing. No tissue damage, gas embolism, biotoxicity, and physicochemical risk were observed.

CONCLUSION

Bioinert DDFP was feasible, efficient, and safe as the novel submucosal lifting candidate.

A New Ex Vivo Model for the Evaluation of Endoscopic Submucosal Injection Material Performance

Increasing the performance of submucosal injection materials (SIMs) is important for endoscopic therapy of early gastrointestinal cancer. It is essential to establish an ex vivo model that can evaluate SIM performance accurately, for developing high-performance SIMs. In our previous study, we developed a new ex vivo model that can be used to evaluate the performance of various SIMs in detail by applying constant tension to the specimen's ends. We also confirmed that the proposed new ex vivo model allows accurate submucosal elevation height (SEH) measurement under uniform conditions and detailed comparisons of the performances of various types of SIMs. Here, we describe the new ex vivo model and explain the detailed setup methodology of this model. Since all parts of the new model were easy to obtain, the setup of the new model could be completed quickly. SEH of various SIMs could be measured more accurately by using the new model. The critical factor that determines SIM performance can be identified using the new model. SIM development speed will drastically increase after the factor has been identified.

Identification of the critical viscoelastic factor in the performance of submucosal injection materials

High-performance submucosal injection materials (SIMs) contribute to the success of endoscopic therapy for early-stage gastrointestinal neoplasms. This study aimed to identify the most important factor (viscoelastic parameter) that determines SIM performance and the ease of injection. To determine the ideal viscoelastic parameters of SIMs, submucosal elevation heights (SEHs) and the ease of submucosal injection [characterized by injection pressures (IPs)] were evaluated using a newly developed ex vivo model, in which a constant tension was applied to the studied specimen. The strongest positive correlation was observed between the loss modulus determined at an oscillation frequency of 0.1 rad/s and SEH (correlation coefficient > 0.9) and between the loss modulus at 10 rad/s and IP (correlation coefficient > 0.9). SIMs with high loss moduli (0.1 rad/s) also contributed to maintenance of the submucosal elevation. Moreover, the SEHs of pseudoplastic fluid SIMs (whose loss moduli increased slightly with increasing angular frequency) were greater than those of Newtonian fluid SIMs (whose loss modulus increased drastically with increasing angular frequency). In this study, the ideal viscoelastic SIM parameters were clarified. The loss modulus (0.1 rad/s) was the most important viscoelastic factor affecting SIM performance. Additionally, the development of pseudoplastic fluid SIMs may lead to the creation of next-generation SIMs, with a performance superior to that of sodium hyaluronate, which is currently used widely in endoscopic treatments.

A novel submucosal injection solution for endoscopic resection of large colorectal lesions: a randomized, double-blind trial

BACKGROUND AND AIMS

SIC-8000 (Eleview) is a new U.S. Food and Drug Administration (FDA)-approved solution for submucosal injection developed to provide a long-lasting cushion to facilitate endoscopic resection maneuvers. Our aim was to compare the efficacy and safety of SIC-8000 with those of saline solution, when performing EMR of large colorectal lesions.

METHODS

In a randomized double-blind trial, patients undergoing EMR for colorectal non-pedunculated lesions ≥20 mm were randomized in a 1:1 ratio between SIC-8000 and saline solution as control solution in 5 tertiary centers. Endoscopists and patients were blinded to the type of submucosal solution used. Total volume to complete EMR and per lesion size and time of resection were primary endpoints; the Sydney Resection Quotient (SRQ), as well as other EMR outcomes, and the rate of adverse events were secondary endpoints. A 30-day telephone follow-up was performed. An alpha level <0.05 was considered as statistically significant.

RESULTS

Of the 327 patients screened, 226 (mean age, 66 ± 10 years; males, 56%) were enrolled in the study and randomized between the 2 submucosal agents. Of these, 211 patients (mean size of the lesions 33 ± 13 mm; Paris class Is, 36%; proximal colon, 74%) were entered in the final analysis (SIC-8000, 102; saline solution, 109). EMR was complete in all cases. The total volume needed for EMR was significantly less in the SIC-8000 arm compared with saline group (16.1 ± 9.8 mL vs 31.6 ± 32.0 mL; P < .001). This corresponded to an average volume per lesion size of 0.5 ± 0.3 mL/mm and 0.9 ± 0.6 mL/mm with SIC-8000 and saline solution, respectively (P < .001). The mean time to completely resect the lesion tended to be lower with SIC-8000 than with saline solution (19.1 ± 16.8 minutes vs 29.7 ± 68.9 minutes; P = .1). The SRQ was significantly higher with SIC-8000 compared with saline solution (10.3 ± 8.1 vs 8.0 ± 5.7; P = .04) with a trend for a lower number of resected pieces (5.7 ± 6.0 vs 6.5 ± 5.04; P = .052) and a higher rate of en bloc resections (19/102, 18.6% vs 12/111, 11.0%; P = .1). The rate of adverse events was similar between the 2 arms (SIC-8000, 18.6%; saline solution, 17%), and none of the serious adverse events (SIC-8000, 8.8%; saline solution, 10.7%) were related to the study treatment.

CONCLUSIONS

In a double-blind, randomized clinical trial, a new FDA-approved agent for sub-mucosal injection appeared to be a more effective and equally safe submucosal agent for EMR injection than saline solution. (Clinical trial registration number: NCT02654418.).

Utility and performance characteristics of a novel submucosal injection agent (EleviewTM) for endoscopic mucosal resection and endoscopic submucosal dissection

Background

Submucosal injection of a lifting agent is a critical step in endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD). Literature suggests superiority of other viscous solutions over normal saline (NS), but research to determine the ideal submucosal injection is still ongoing. In this prospective cohort study, we evaluated the utility and performance characteristics of a novel submucosal injection agent (Eleview^TM) for EMR and ESD.

Methods

Twelve consecutive patients referred for EMR/ESD to a tertiary referral center with experienced large polyp expert were prospectively enrolled. Ten patients with large colon polyps (mean age 66.3 years), and one patient each with esophageal and gastric lesions were included. Eleview^TM was injected as submucosal lifting agent, and EMR/ESD performed. Main outcome measurements included the duration of submucosal elevation, volume and number of injections required to maintain cushion, and complications.

Results

Single injection of 3-5 cc of Eleview^TM outlasted the duration of EMR. However, mean duration of cushion achieved during longer procedures (ESD) was 12.5 min, requiring several additional injections. R0 resection was achieved in 10/12 patients. One patient had minor bleeding which was managed intra-operatively.

Conclusions

Eleview^TM was successful in achieving long duration of submucosal elevation, allowing safe and efficient performance of EMR as a single injection, but needed repeated injections during longer ESD procedures. Prospective controlled trials are required to compare its performance to other available viscous submucosal solutions.

Efficacy and safety of SIC-8000 (Eleview®) for submucosal injection for endoscopic mucosal resection and endoscopic submucosal dissection in an in vivo porcine model

BACKGROUND

Submucosal injection is generally required for both endoscopic-mucosal resection (EMR) and submucosal dissection (ESD). SIC-8000 (Eleview™) is a new FDA 510(k) cleared and CE marked liquid composition for submucosal injection, containing a biocompatible polymer as a cushioning agent.

AIMS

The aim of this randomized study was to compare Eleview with saline solution when performing upper- and lower-GI EMR/ESD in a porcine model.

METHODS

EMR/ESD procedures were performed in a total of 10 white domestic pigs comparing Eleview vs. NaCl 0.9% containing methylene blue at 0.001% (control solution) as submucosal solution to be injected. Animals were randomized between EMR (22 procedures) and ESD (22 procedures) and between upper- (8 animals) and lower-(2 animals) GI procedures. All procedures were performed aiming for a resection size of 1 cm × 1 cm for EMR and 2 cm × 2 cm for ESD. Volume of injected fluid, number of injections, time of resection, technical success, en-bloc resection, and adverse events were collected. Endoscopic surveillance was conducted each week for 4 weeks after the EMR/ESD, including biopsies on the margins of resection sites at week-1 of follow-up. After four weeks, pigs were sacrificed and necropsy performed.

RESULTS

Overall, 22 EMR and 22 ESD were performed in 10 live pigs. The average total volume needed for EMR and ESD was statistically significantly lower with Eleview as compared with control solution for both of the techniques (EMR: 5.6 ± 3.4 ml vs. 11.5 ± 6.7 ml; p = 0.02; ESD: 19.0 ± 10.0 ml vs. 36.3 ± 16.9 ml; p = 0.02). The rate of adverse events was statistically significantly lower in the Eleview than in the control group (2/26, 7.7% vs. 6/18, 33.3%; p = 0.03), but most of them were minor. No difference between Eleview and control solution was found in the rate of technical success (EMR: 11/13, 84.6% vs. 7/9, 77.8%; p = 0.7; ESD: 13/13, 100% vs. 9/9, 100%; p = 1), en-bloc resection (EMR: 6/13, 46.2% vs. NaCl: 5/9, 55.6%; p = 0.06; ESD: 12/13, 92.3% vs. 8/9, 88.9%; p = 0.8), and time of resection (EMR: 9.1 ± 7.75 min vs. 9.4 ± 9.6 min; p = NS; ESD: 38.4 ± 17.2 min vs. 40.2 ± 19.1 min; p = NS). At endoscopic follow up and necropsy, no difference in the process of healing of post-endoscopic ulcer and in the histological inflammation at the site of resection was shown between the two groups.

CONCLUSIONS

The new submucosal injection composition Eleview appeared to be an effective alternative to saline solution for submucosal injection for EMR/ESD, resulting in a substantial reduction of the volume administered to achieve an adequate lifting. No signs of adverse local or distant tissue reaction to Eleview were found at long-term follow up.

Development of a new ex vivo model for evaluation of endoscopic submucosal injection materials performance

BACKGROUND AND AIMS

Development of high-performance submucosal injection materials (SIMs) contribute to the advancement of endoscopic therapy for early-stage gastrointestinal neoplasms. This study aimed to develop a new ex vivo model that mimics the human gastrointestinal tract to evaluate the performance (the height and duration of the submucosal elevation) of various SIMs in detail.

METHODS

A new ex vivo model that applies a constant tension to the tested specimen (the porcine gastric specimen) was developed. SIMs were injected into the submucosa at the center or edge of the tested specimen, and submucosal elevation heights (SEHs) were measured over time.

RESULTS

The average value and standard deviation of SEH determined using the conventional model (the tested specimen was fixed with pins) were higher than those obtained using the new model, which showed that the new model could precisely measure the SEH of a given SIM. In addition, the performance (SEH) of SIMs decreased with increasing tension applied to the specimen, suggesting that the performance of SIMs deteriorates with the over-expansion of the gastrointestinal tract. The submucosal elevation formed at the specimen edge disappeared faster than that formed at the specimen's center.

CONCLUSIONS

The proposed new ex vivo model allows accurate SEH measurement under uniform conditions and detailed comparison of the performances of various types of SIMs and can contribute to the development of high-performance materials.

Standard needle versus needleless injection modality: animal study on different fluids for submucosal elevation

BACKGROUND AND AIMS

Submucosal injection is currently used in GI endoscopy to reduce resection risks and to perform submucosal dissection; it is usually performed via an injection needle or a needleless device. The aim of the study was to compare 2 submucosal injection modalities (needle-assisted vs needleless) by using substances with different viscosities.

METHODS

Needle and needleless injections were compared by assessing the efficacy of tissue elevation with 5 different substances in an ex vivo porcine model. The height of the submucosal elevation was measured 0(t0), 10(t1), and 30 minutes after injection (t2). Viscosity of the solution was also measured.

RESULTS

For both stomach and rectum, at t0, t1, and t2 no difference in the height of the elevation was found between the needle and needleless technique, irrespective of the substance. Tissue elevation in the stomach was similar between the 2 techniques at t0 (9.9 ± 1.58 vs 9.4 ± 1.3 mm, P = .3), t1 (7.2 ± 1.56 vs 6.9 ± 1.4 mm, P =. 26), and t2 (6 ± 1.6 vs 5.5 ± 1.3 mm, P = .18). No difference was found in the rectum at t1 and t2, whereas a slightly higher elevation with the needle-assisted technique was observed at t0 (t0: 12.4 ± 1.3 vs 11.2 ± 1.6 mm, P = .003; t1: 8.7 ± 1.3 vs 8.3 ± 1.5 mm; P = .32; t2: 7.0 ± 1.4 vs 7.2 ± .76 mm; P = .75). When comparing the substances with normal saline solution, more viscous solutions showed a significantly higher elevation at t0, t1, and t2 irrespective of the injection modalities and the location.

CONCLUSIONS

No differences were found in the height of submucosal injection or in the persistence of such elevation when comparing needleless with needle-assisted injection, with the only minor exception of the initial elevation in the rectum, which does not appear to be clinically relevant. Viscous solutions resulted in higher and more persistent elevations as compared with normal saline solution.

Normal saline solution versus other viscous solutions for submucosal injection during endoscopic mucosal resection: a systematic review and meta-analysis

BACKGROUND AND AIMS

EMR is being increasingly practiced for the removal of large colorectal polyps. A variety of solutions such as normal saline solution (NS) and other viscous and hypertonic solutions (VS) have been used as submucosal injections for EMR. A systematic review and meta-analysis is presented comparing the efficacy and adverse events of EMR performed using NS versus VS.

METHODS

Two independent reviewers conducted a search of all databases for human, randomized controlled trials that compared NS with VS for EMR of colorectal polyps. Data on complete en bloc resection, presence of residual lesions, and adverse events were extracted using a standardized protocol. Pooled odds ratio (OR) estimates along with 95% confidence intervals (CI) were calculated using fixed effect or random effects models.

RESULTS

Five prospective, randomized controlled trials (504 patients) met the inclusion criteria. The mean polyp sizes were 20.84 mm with NS and 21.44 mm with VS. On pooled analysis, a significant increase in en bloc resection (OR, 1.91; 95% CI, 1.11-3.29; P = .02; I² = 0%) and decrease in residual lesions (OR, 0.54; 95% CI, 0.32-0.91; P = .02; I² = 0%) were noted in VS compared with NS. There was no significant difference in the rate of overall adverse events between the 2 groups.

CONCLUSIONS

Use of VS during EMR leads to higher rates of en bloc resection and lower rates of residual lesions compared with NS, without any significant difference in adverse events. Endoscopists could consider using VS for EMR of large colorectal polyps and NS for smaller polyps because there is no significant difference in the outcomes with lesions <2 cm.

Endoscopic Approach for Superficial Colorectal Neoplasms

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in males and the second in females, with an estimated 1.4 million cases and 693,900 deaths in 2012. Colonoscopy is the cornerstone for the detection and prevention of CRC. In addition, endoscopic treatment for CRC at an early stage can effectively improve patients' quality of life and cure rate.

SUMMARY

This review focuses on endoscopic approaches, including white light endoscopy, chromoendoscopy, magnifying endoscopy and therapeutic endoscopy, for the evaluation and treatment of superficial colorectal neoplasms.

KEY MESSAGE

Understanding the preoperative evaluation, indications and techniques of endoscopic mucosal resection/endoscopic submucosal dissection as well as postoperative surveillance for superficial colorectal neoplasms is critical for providing appropriate management to the patients.

PRACTICAL IMPLICATIONS

Endoscopic therapy, a method preserving organ function and improving quality of life, is a widely applied microinvasive treatment for superficial colorectal neoplasms. This review describes the basics and developments of endoscopic approaches and may facilitate daily practice for superficial colorectal neoplasms.

Safe and Efficient Colonic Endoscopic Submucosal Dissection Using an Injectable Hydrogel

Endoscopic submucosal dissection (ESD) has not yet been widely adopted in the treatment of early colonic cancers due to the greater technical difficulty involved, longer procedure time, and the increased risk of perforation. Adequate mucosal elevation by submucosal injection is crucial for en bloc resection and prevention of perforation during colonic ESD. This study is aimed to evaluate the efficacy of an injectable thermoreversible hydrogel as the colonic submucosal agent for the first time. Triblock copolymer poly(lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) was synthesized, and its concentrated aqueous solution was injected into the colonic submucosa of living minipig and spontaneously transformed into an in situ hydrogel with adequate mucosal elevation at body temperature. Such a mucosal lifting lasted for a longer time than that created by the control group, glycerol fructose. Colonic ESD was then performed with the administration of hydrogels at various polymer concentrations or glycerol fructose. All colonic lesions were successfully resected en bloc after one single injection of the hydrogel, and repeated injections were not needed. No evidence of major hemorrhage, perforation and tissue damage were observed. Considering the injection pressure, duration of mucosal elevation and efficacy of "autodissection", the hydrogel containing 15 wt % polymer was the optimized system for colonic ESD. Consequently, the thermoreversible hydrogel is an ideal submucosal fluid that provides a durable mucosal lifting and makes colonic ESD accessible to a large extent. In particular, the efficacy of "autodissection" after one single injection of the hydrogel simplifies significantly the procedures while minimizing the complications.