Endoscopic full-thickness GI wall resection: current status

Assessment and Techniques for Endoscopic Closure

Endoscopic closure is an essential technique to perform safe advanced endoscopy. Without appropriate closure of a defect, patients can experience spillage of fecal contents into the peritoneal cavity resulting in abdominal sepsis. The essential components to performing endoscopic closure are assessing the defect appropriately and choosing the correct closure technique. Assessing the defect involves five separate elements: timing, size, depth, shape, blood flow, and location in the colon or rectum. Understanding how each of these elements contributes toward a successful closure allows an endoscopist to choose the proper technique for closure. There have been many types of closure techniques described in the literature but the most common are through the scope clips, over the scope clips, and endoscopic suturing. There are advantages and disadvantages of each of these closure techniques. In this manuscript, we will discuss these common techniques as well as some additional techniques and the situations where they can be employed.

Over-the-scope clip-assisted endoscopic full thickness resection: a video-based case series

BACKGROUND

In the management of mucosal neoplasm and early cancer, therapeutic gastrointestinal endoscopy evolved from simply polypectomy, endoscopic mucosal resection, endoscopic submucosal dissection (ESD), to endoscopic full thickness resection (EFTR). Full thickness clip closure followed by transmural resection mimics surgical principles. It is safe, effective, and technically less demanding compared to other techniques. Over-the-scope clip (OTSC)-assisted EFTR or OTSC-EFTR enables the endoscopists to manage difficult lesions.

METHODS

We video recorded and report our 1-year single center experience of 12 consecutive EFTR cases since the dedicated OTSC-EFTR device was approved in the USA.

RESULTS

We demonstrate that OTSC-EFTR can be very useful to manage residual neoplastic tissue that cannot be removed during conventional mucosal resection due to deeper invasion, submucosal fibrosis, scaring from prior intervention, and appendiceal involvement. Caution should be used for EFTR of the ileocecal valve lesions.

CONCLUSION

We propose that layered or stacked biopsy of the appendiceal stump after EFTR should be performed to rule out a positive residual base. Due to the limited size of the FTRD resection hood (13 mm internal diameter × 23 mm depth), for larger sessile adenomas in the colon, we propose a hybrid approach for complete removal: piecemeal EMR for tumor debulking followed by OTSC-EFTR to achieve R0 resection. We believe OTSC-EFTR offers safety and efficiency with very high success rate.

The efficacy of dental floss and a hemoclip as a traction method for the endoscopic full-thickness resection of submucosal tumors in the gastric fundus

BACKGROUND

Endoscopic full-thickness resection (EFTR) provides a significant advancement to the treatment of gastrointestinal submucosal tumors (SMTs). However, technological challenges, particularly in the gastric fundus, hinder its wider application. Here, we investigated the efficacy of a simple traction method that used dental floss and a hemoclip (DFC) to facilitate EFTR.

METHODS

Between July 2014 and December 2016, we retrospectively reviewed data from all patients with SMTs in the gastric fundus originating from the muscularis propria layer that were treated by EFTR at Zhongshan Hospital of Fudan University. Baseline characteristics and clinical outcomes, including procedure time and complications rate, were compared between groups of patients receiving DFC-EFTR and conventional EFTR.

RESULTS

A total of 192 patients were included in our analysis (64 in the DFC-EFTR group and 128 in the conventional EFTR group). Baseline characteristics for the two groups were similar. The mean time for DFC-EFTR and conventional EFTR was 44.2 ± 24.4 and 54.2 ± 33.2 min, respectively (P = 0.034). Although no serious adverse events presented in any of our cases, post-EFTR electrocoagulation syndrome (PEECS), as a minor complication, was less frequent in the DFC-EFTR group (3.1% vs. 12.5%, P = 0.036). Univariate and multivariate analysis identified that DFC, when used in EFTR, played a significant role in reducing procedure time and the rate of PEECS. The mean procedure time was significantly shorter in the DFC-EFTR group for lesions over 1.0 cm (P = 0.005), when the lesions were located in the greater curvature of the gastric fundus (P = 0.025) or when the lesions presented with intraluminal growth (P = 0.032). Moreover, when EFTR was carried out by experts, the mean procedure time was 20.4% shorter in the DFC-EFTR group (P = 0.038).

CONCLUSIONS

This study indicated that DFC-EFTR for SMTs in the gastric fundus resulted in a shorter procedure time and reduced the risk of PEECS, a minor complication.

Comparison of two methods for endoscopic full-thickness resection of gastrointestinal lesions using OTSC

Background and aims: The aim of this study was to compare and analyze the feasibility and safety of two methods of endoscopic full-thickness resection (EFTR) for the management of challenging epithelial and subepithelial neoplasms that are not amenable to resection techniques.Material and methods: This was a retrospective case series study of patients who underwent one of two methods of EFTR, resection using ESD knives and post-resection closure with OTSC (Group 1), or closure with OTSC and secondary EFTR with snare (Group 2).Results: Of 11 patients, six were in Group 1 and five in Group 2. The mean time of the EFTR procedure was 76.83 ± 34.97 min in Group 1 which is significantly longer than that of Group 2 (p = .0128). The mean time of OSTC closure and length of hospital stay of Group 1 were also longer compared to Group 2, but the difference was not significant. Complete resection (R0) and technical success rates of Group 1 and Group 2 were 83.3% and 100% (p = .338), respectively. VAS scores of Group 1 immediately after the operation and after 24 h are significantly higher than those of Group 2 (p = .047 and p = .009, respectively). In Group 1, one patient had delayed perforation which led to fever and pneumoperitoneum, and one patient developed abdominal pain. No complications associated with the endoscopic procedure were observed in Group 2.Conclusion: EFTR of pre-resection closure are potentially faster compared with the concept of applying closure after EFTR. Larger prospective controlled studies comparing these two techniques are warranted in the future.

The prepurse-string suture technique for gastric defect after endoscopic full-thickness resection (with video)

Endoscopic full-thickness resection (EFTR) is the main treatment for gastric tumors originating from the muscularis propria or gastric extra-luminal growth tumors. Successful closure of the gastric wall defect is a critical step during EFTR.The aim of this retrospective study was to evaluate the feasibility and safety of the endoscopic prepurse-string suture (p-EPSS) technique using an endoloop and several metallic clips during EFTR to close the perforation.Twenty-five patients with gastric tumors originated from the muscularis propria or with gastric extra-luminal growth tumors who received EFTR were analyzed at the Renmin Hospital of Wuhan University from June 2016 to May 2017. Patient characteristics, tumor characteristics, operation time length, and postoperative complications were evaluated in all patients.All the 25 patients underwent a successful EFTR. Complete closure of gastric defects was also achieved. The mean operation time length was 31 ± 14 minutes. The mean maximum size of tumor of was 1.7 ± 1.0 cm (range 0.5-4.5 cm). No severe postoperative complications occurred, such as massive bleeding, gastric leak, peritonitis, or abdominal abscess. No patient needed surgical intervention. Wounds were well healed 1 month after EFTR. No tumor metastasis and recurrence were observed during the follow-up period (median, 7 months).The p-EPSS technique using endoloop and several sterile repositionable hemostasis clips is safe and feasible for closing gastric perforation during EFTR.

Endoscopic full-thickness resection of superficial colorectal neoplasms using a new over-the-scope clip system: A single-centre study

BACKGROUND AND AIM

Endoscopic full-thickness resection (EFTR) provides complete en-bloc resection with a histopathological evaluation of submucosal, muscular, and serosal layers. The aim of this study was to investigate the efficacy and safety of a novel over-the-scope device for colorectal EFTR.

MATERIAL AND METHODS

In this retrospective, observational, open-label case study, a total of 20 patients with superficial colorectal neoplasms, underwent EFTR using a new endoscopic full-thickness resection device (FTRD; Ovesco Endoscopy, Tübingen, Germany). Endoscopic treatment outcomes (technical success, rate of EFTR, adverse events) and early follow-up at three months, were analyzed.

RESULTS

We reported a 100% of technical success, defined as full-thickness resection. Among the R1 resections, histology was negative for neoplasm. Non-lifting adenomas had histology positive for adenocarcinoma: seven T1/G1/sm1; one T1/G1/sm2; one, who underwent a surgical resection, T1/G1/sm3. Mean size of the resected lesions was 26mm, ranging from 10 to 42mm. One (5%) patient developed abdominal pain, fever and leukocytosis and was treated conservatively with medical therapy. In all specimens, histological complete resection was confirmed.

CONCLUSIONS

EFTR is a feasible and effective technique that could become a valid alternative to EMR and ESD in the management of recurrent adenomas, no-lifting lesions and scars of R1 resections. However, prospective studies are needed to further evaluate the device and technique.

Application of novel endoloops to close the defects resulted from endoscopic full-thickness resection with single-channel gastroscope: a multicenter study

BACKGROUND

The key step of the endoscopic full-thickness resection (EFTR) procedure is the successful closure of any gastric wall defect which ultimately avoids surgical intervention. This report presents a new method of closing large gastric defects left after EFTR, using metallic clips and novel endoloops by means of single-channel endoscope.

METHODS

We retrospectively analyzed 68 patients who were treated for gastric fundus gastrointestinal stromal tumors originating from the muscularis propria layer at four institutes between April 2014 and February 2015 and consequently underwent EFTR. The large gastric post-EFTR defects were completely closed with metallic clips and novel endoloops using single-channel endoscope, and all the patients were discharged with subsequent endoscopic and clinical follow-up. Patient characteristics, tumor size, en bloc resection rate, closure operation time, and postoperative adverse events were evaluated.

RESULTS

EFTR was successfully performed on 68 patients [41 male (60 %), 27 female (40 %); median age 61 years, range 38-73], and the en bloc resection rate was 100 %. Complete closure of all the gastric post-EFTR defects was achieved (success rate 100 %). The mean closure operation time was 13 min (range 9-21 min). The mean maximum size of the lesions was 2.6 cm (range 2.0-3.5 cm). One Mallory-Weiss syndrome and one delayed bleeding were resolved with nonsurgical treatment. The wounds were healed in all cases 1 month after the procedure.

CONCLUSIONS

The use of metallic clips and novel endoloops with single-channel endoscope is a relatively safe, easy, and feasible method for repairing large gastric post-EFTR defects.

Detection and Management of Early Gastric Cancer

OPINION STATEMENT

Early gastric cancer (EGC), defined as being confined to the submucosa, is a curable condition. In recent years, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been widely applied to subgroups of mucosal cancers, thereby avoiding the burden of operation while preserving gastric function. However, it can be difficult to identify mucosal cancers, which often evade detection due to their flat shapes without ulceration. Proper preparation to clean the mucosal surface, detailed systematic observation of the entire stomach, and the use of high-resolution systems for both endoscopies equipped with image-enhanced modality and monitors would facilitate the detection of such lesions. It is also critical to evaluate the resected specimen to confirm completeness of resection (tumor-free lateral and vertical margins as well as the absence of lymphatic and vascular invasion). If the resection is incomplete, further treatment is usually recommended-further endoscopic resection for patients with positive lateral margins or surgery for patients with positive vertical margins or with lymphatic or vascular involvement. The five-year survival for endoscopically resected EGC is excellent-and comparable to that of surgical therapy. Since most gastric cancers are caused by Helicobacter pylori, this infection should be tested for routinely. If a patient is H. pylori-positive, eradication is recommended, as heterotopic, metachronous recurrence of EGC is subsequently reduced. Importantly, basic principles for early diagnosis and endoscopic treatment of EGC can be applied to neoplasms arising in other parts of the gut, such as the esophagus and colon, and would be beneficial for patients through preserving organ function and minimizing operative intervention.

Facilitating retroflexed endoscopic full-thickness resection through loop-mediated or rope-mediated countertraction (with videos)

BACKGROUND AND AIMS

Endoscopic full-thickness resection (EFTR) is difficult to perform in a retroflexed fashion in the gastric fundus and lesser curvature. Here we describe two simple methods to provide countertraction and thereby facilitate dissection.

METHODS

In this retrospective cohort study, 62 patients diagnosed as having gastric submucosal tumors in the fundus or in the lesser curvature received EFTR with or without countertraction methods. For the clip-with-thread method, a clip tied with surgical suture was anchored on the distal edge of the tumor to provide countertraction; for the loop-assisted method, a snare placed on the transparent cap beforehand was adopted to grasp the tumor to provide countertraction.

RESULTS

Mean operative time was significantly reduced in the thread-with-clip group and loop-assisted group (45 minutes, 40 minutes, respectively) compared with the time needed in the traditional EFTR group (85 minutes). Intraoperative pneumoperitoneum occurred regularly among the 3 groups because of iatrogenic perforation, but fewer patients in the thread-with-clip group and loop-assisted group (23%, 18%, respectively) needed abdominal puncture to relieve free air and stabilize life signs compared with patients in the traditional EFTR group (63%). A reduced occurrence of high fever after surgery may contribute as another advantage from accelerated dissection. Both techniques did not jeopardize oncologic safety during short-term follow-up.

CONCLUSIONS

Both the thread-with-clip method and loop-assisted method provide effective countertraction and offer faster and safer gastric EFTR in difficult anatomic locations.

Risk of infection after iatrogenic perforation of the gut wall? Evaluation of preventive strategies in a randomized controlled animal trial

BACKGROUND

Interventional endoscopies entail a risk of infection secondary to perforation of the luminal wall. Thereby, bacteria may be introduced into the sterile environment of the peritoneal cavity (PC). Limited data are available regarding the efficacy of prophylactic anti-infective treatments. The aim of the study was to examine the efficacy/safety of anti-infective means in the prevention of infection by interventional endoscopies in a randomized controlled animal trial.

METHODS

Forty pigs were randomized to: 1: control; 2: oral lavage; 3: gastric lavage; 4: oral/gastric lavage; 5: i.m. antibiotics. Lavage was performed with Octenisept prior to the operation. After gastric wall perforation, peritoneoscopy was performed. Before the procedure, after closure and prior to autopsy, intraabdominal lavage for bacterial culture was taken using mini-laparoscopy. At autopsy, macroscopic appearance of the PC was scored. Lavage fluids were grown to identify/quantify bacterial load. Concentration of intraperitoneal bacteria at autopsy was defined as main outcome parameter.

RESULTS

No major complications occurred in any of the procedures. Bacterial load of the PC at autopsy was significantly reduced with antibiotics compared to all other groups, whereas it did not differ between the lavage groups and control. Macroscopic scoring of the PC showed significant lower rate of intraabdominal abscesses in the antibiotic group compared to the lavage groups and control (p < 0.01).

CONCLUSION

Only antibiotic prophylaxis is effective for the prevention of infection after iatrogenic perforation of the gastrointestinal wall. There was no difference between any form of lavage and the control group. Further studies in humans are required to prove these animal data.

Duodenal endoscopic full-thickness resection (with video)

BACKGROUND AND AIMS

Endoscopic resection of duodenal non-lifting adenomas and subepithelial tumors is challenging and harbors a significant risk of adverse events. We report on a novel technique for duodenal endoscopic full-thickness resection (EFTR) by using an over-the-scope device.

METHODS

Data of 4 consecutive patients who underwent duodenal EFTR were analyzed retrospectively. Main outcome measures were technical success, R0 resection, histologic confirmation of full-thickness resection, and adverse events. Resections were done with a novel, over-the-scope device (full-thickness resection device, FTRD).

RESULTS

Four patients (median age 60 years) with non-lifting adenomas (2 patients) or subepithelial tumors (2 patients) underwent EFTR in the duodenum. All lesions could be resected successfully. Mean procedure time was 67.5 minutes (range 50-85 minutes). Minor bleeding was observed in 2 cases; blood transfusions were not required. There was no immediate or delayed perforation. Mean diameter of the resection specimen was 28.3 mm (range 22-40 mm). Histology confirmed complete (R0) full-thickness resection in 3 of 4 cases. To date, 2-month endoscopic follow-up has been obtained in 3 patients. In all cases, the over-the-scope clip was still in place and could be removed without adverse events; recurrences were not observed.

CONCLUSIONS

EFTR in the duodenum with the FTRD is a promising technique that has the potential to spare surgical resections. Modifications of the device should be made to facilitate introduction by mouth. Prospective studies are needed to further evaluate efficacy and safety for duodenal resections.

Endoscopic full-thickness resection: Current status

Conventional endoscopic resection techniques such as endoscopic mucosal resection or endoscopic submucosal dissection are powerful tools for treatment of gastrointestinal neoplasms. However, those techniques are restricted to superficial layers of the gastrointestinal wall. Endoscopic full-thickness resection (EFTR) is an evolving technique, which is just about to enter clinical routine. It is not only a powerful tool for diagnostic tissue acquisition but also has the potential to spare surgical therapy in selected patients. This review will give an overview about current EFTR techniques and devices.

Comparison of endoscopic band ligation and endoclip closure of colonic perforation: technical feasibility and efficacy in an ex vivo pig model

BACKGROUND AND AIM

Recent reports have indicated several instances of successful treatment of bowel perforation by using endoscopic band ligation (EBL) when treatment with endoclipping is unsuccessful, but this salvage method has not been investigated in any prospective model. Herein we aimed to compare the technical feasibility and efficacy of EBL and endoclip use in intraluminal closure of colon perforation, in an ex vivo model.

METHODS

Standardized colonic perforations were created using fresh porcine colon and subsequently closed by full-thickness interrupted sutures, endoclip (QuickClip2(TM)), or EBL. Each closure site was tested with compressed air by using a digital pressure monitor for evaluating leak pressure.

RESULTS

No significant differences were noted between the endoclip and EBL in leak pressures. Mean (± SD) pressures for air leakage from the perforations closed using the different devices were as follows: normal colon samples, 52.0 ± 13.2 mmHg; perforations closed with hand-sewn sutures, 32.3 ± 8.3 mmHg; perforations closed with endoclipping, 53.5 ± 22.7 mmHg; and perforations closed with EBL, 50.4 ± 12.5 mmHg. Time taken for closure by EBL was significantly less than that for closure by endoclipping (3.2 ± 1.7 min vs 6.8 ± 1.3 min, P < 0.01). Further, the number of devices used to achieve complete closure in the EBL group was lower than that with endoclipping (1.6 ± 0.5 vs 3.7 ± 0.8, P < 0.01).

CONCLUSION

Endoluminal closure of a 1.5-cm colon perforation with EBL decreased procedure time and was not inferior in leak pressure compared with endoclipping in this ex vivo porcine model.

Current innovations in endoscopic therapy for the management of colorectal cancer: from endoscopic submucosal dissection to endoscopic full-thickness resection

Endoscopic submucosal dissection (ESD) is accepted as a minimally invasive treatment for colorectal cancer. However, due to technical difficulties and an increased rate of complications, ESD is not widely used in the colorectum. In some cases, endoscopic treatment alone is insufficient for disease control, and laparoscopic surgery is required. The combination of laparoscopic surgery and endoscopic resection represents a new frontier in cancer treatment. Recent developments in advanced polypectomy and minimally invasive surgical techniques will enable surgeons and endoscopists to challenge current practice in colorectal cancer treatment. Endoscopic full-thickness resection (EFTR) of the colon offers the potential to decrease the postoperative morbidity and mortality associated with segmental colectomy while enhancing the diagnostic yield compared to current endoscopic techniques. However, closure is necessary after EFTR and natural transluminal endoscopic surgery (NOTES). Innovative methods and new devices for EFTR and suturing are being developed and may potentially change traditional paradigms to achieve minimally invasive surgery for colorectal cancer. The present paper aims to discuss the complementary role of ESD and the future development of EFTR. We focus on the possibility of achieving EFTR using the ESD method and closing devices.

Complete defect closure of gastric submucosal tumors with purse-string sutures

BACKGROUND

Gastric submucosal tumors (SMTs) originating from the muscularis propria layer are treated endoscopically. Successful closure of the wall defect is a critical step. This study evaluated the safety and feasibility of the endoscopic purse-string suture (EPSS) method using an endoloop and several metallic clips after endoscopic full-thickness resection (EFTR) or perforation due to endoscopic submucosal dissection (ESD).

METHODS

From December 2009 to April 2013, 30 patients with SMTs originating from the muscularis propria layer who received EFTR or ESD were retrospectively analyzed. After successful tumor resection, an endoloop was anchored onto the circumferential margin of the gastric defect with several metallic clips and tightened gently. Patient characteristics, tumor size, en bloc resection, and postoperative complications were evaluated.

RESULTS

For all 30 patients, EPSS was successfully performed after EFTR or perforation due to ESD. The mean diameter of the resected specimen was 1.9 cm. No severe complications occurred during or after the procedure. The lesions were healed 1 month after the procedure, as confirmed endoscopically.

CONCLUSION

The EPSS method using an endoloop and clips is an effective and safe technique for closing the gastric defect after EFTR or perforation due to ESD.

Feasibility of full-thickness gastric resection using master and slave transluminal endoscopic robot and closure by Overstitch: a preclinical study

BACKGROUND

Gastric submucosal tumors are often treated by laparoscopic wedge resection. This study aimed to examine the feasibility of gastric full-thickness resection through a totally endoscopic approach using the master and slave transluminal endoscopic robot (MASTER), and closure of the luminal defect with an endoscopic suturing device.

METHODS

The operation was performed in two live porcine models under general anesthesia. First, the anterior wall of the stomach was slung to the abdominal wall using a percutaneous suturing device. An imaginary 5-cm lesion was marked using a needle knife. After the initial mucosal incision was made using an IT knife, the MASTER was introduced through a long overtube. A circumferential mucosal incision was completed with the MASTER to expose the muscularis propria which was grasped and incised to the serosal layer by electrocautery applied through the hook of the MASTER. The full-thickness resection of the gastric wall was completed with retraction using the grasper and dissection using the hook. While the defect was being created, the luminal space was maintained with traction of the percutaneous sutures. The defect was closed with suture plication using an Apollo Overstitch device.

RESULTS

Two full-thickness gastric resections were performed in two nonsurvival porcine models (body weight = 30 and 35 kg, respectively) using the MASTER. The total procedure time was 56 min for the first model and 70 min for the second model. The luminal view was maintained during the whole procedure, and there was no damage to surrounding organs throughout the whole procedure. The gastric defects were closed successfully using Overstitch, with satisfactory gastric distension and no gas leakage afterward.

CONCLUSION

The current experiment demonstrated the feasibility and safety of a totally endoscopic approach for the treatment of gastric submucosal tumors: full-thickness resection with the MASTER and successful closure of the defect using Overstitch.

A systematic review regarding the feasibility and safety of endoscopic full thickness resection (EFTR) for colonic lesions

PURPOSE

This review summarizes the published methods of colonic EFTR, examining data on feasibility and safety. Due to the introduction of bowel cancer screening programs, there is an increasing incidence of complex colonic polyps and early colonic cancer that requires segmental colectomy. Traditional radical surgery is associated with significant morbidity, and there is a need for alternative treatments.

METHODS

Systematic literature search identified articles describing EFTR techniques of colon, published between 1990 and 2012. Complication rates, anastomotic bursting pressures, procedure duration, specimen size and quality, and postmortem findings were analyzed.

RESULTS

Five research groups reported four EFTR techniques using endoscopic stapling devices, T-tags, compression closure, or laparoscopic assistance for defect closure before or after specimen resection. A total of 113 procedures were performed in 99 porcine models, with an overall success rate of 89 and 4 % mortality. The intraoperative complication rate was 22 % (0-67 %). Post-resection closure methods more commonly resulted in failure to close the defect (5-55 %) and a high incidence of abnormal findings at postmortem examination (84 %). Significant heterogeneity was observed in procedure duration (median or mean 3-233 min) and size of the excised specimen (median or mean 1.7-3.6 cm). Anastomotic bursting pressures and specimen quality were poorly documented.

CONCLUSIONS

The technique of EFTR is developing, but the inability to close the resection defect reliably is a major obstacle. The review highlights the challenges that need to be addressed in future preclinical studies.

Benchtop testing and comparisons among three types of through-the-scope endoscopic clipping devices

BACKGROUND

Through-the-scope (TTS) endoscopic clipping devices are widely used. No benchtop testing or direct comparisons of these endoclips have been performed to show their rotational ability and inherent mechanical strengths during closure and after deployment. This study aimed to provide benchtop data that can be used to guide clinical applications and to promote future device research and development.

METHODS

Benchtop testing and comparisons were performed for three groups of TTS clips: QuickClip2 long, resolution, and instinct clips. The main outcome measurements were device-in-endoscope retroflection angles (DIERA), opening strength, "snapping" force of acute clip closure, and neoprene pulling strength.

RESULTS

The achievable gastroscope DIERA was 10° for QuickClip2, 3° for the resolution clip, and 10° for the instinct clip. The QuickClip and the Instinct clip rotated almost equally well under all endoscope configurations, including endoscopic retrograde cholangiopancreatography (ERCP). With or without a sheath, the resolution clip lacked the ability to rotate. During clip opening force testing (the amount of force required to force open the jaws of a deployed clip by 3.2 mm; 3.2 mm was chosen due to the standard dimension of the gauge used for the measurement), the Instinct clips were the strongest. For the Instinct clips, an opening force of 404 ± 124 g was needed to open the closed clip, and an additional 386 ± 133 g was required to open the clip jaws to 3.2 mm. In terms of snapping force during acute closure and neoprene pulling strength, the instinct and resolution clips performed almost equally. The limitations of the study were the benchtop testing and the finite sample size for closing and pulling strength comparisons.

CONCLUSIONS

The QuickClip2 and the Instinct clip rotate equally well under different endoscope configurations. The resolution clips lack rotational ability. The instinct clips are stronger mechanically than the other two TTS clips. Stronger clips are perhaps associated with higher therapeutic efficacy and retention rates.