Submucosal Tunneling Endoscopic Resection (STER) and Other Novel Applications of Submucosal Tunneling in Humans

Nomogram to predict gas-related complications during transoral endoscopic resection of upper gastrointestinal submucosal lesions

BACKGROUND

Gas-related complications present a potential risk during transoral endoscopic resection of upper gastrointestinal submucosal lesions. Therefore, the identification of risk factors associated with these complications is essential.

AIM

To develop a nomogram to predict risk of gas-related complications following transoral endoscopic resection of the upper gastrointestinal submucosal lesions.

METHODS

We collected patient data from the First Affiliated Hospital of the Army Medical University. Patients were randomly allocated to training and validation cohorts. Risk factors for gas-related complications were identified in the training cohort using univariate and multivariate analyses. We then constructed a nomogram and evaluated its predictive performance based on the area under the curve, decision curve analysis, and Hosmer-Lemeshow tests.

RESULTS

Gas-related complications developed in 39 of 353 patients who underwent transoral endoscopy at our institution. Diabetes, lesion origin, surgical resection method, and surgical duration were incorporated into the final nomogram. The predictive capability of the nomogram was excellent, with area under the curve values of 0.841 and 0.906 for the training and validation cohorts, respectively.

CONCLUSION

The ability of our four-variable nomogram to efficiently predict gas-related complications during transoral endoscopic resection enhanced postoperative assessments and surgical outcomes.

Submucosal Tunneling Techniques for Tumor Resection

The concept of third space endoscopy is based on the principle that the deeper layers of the gastrointestinal tract can be accessed by tunneling in the submucosal space and maintaining the integrity of the overlying mucosa. The mucosal flap safety valve enabled endoscopists to use submucosal space securely. The era of third space endoscopy started with peroral endoscopic myotomy for treatment of achalasia and has expanded to treat various other gastrointestinal disorders, such as mucosal lesions, submucosal tumors, extraluminal tumors, and refractory gastroparesis, Zenker diverticulum, and restoration of the completely obstructed esophageal lumen. Third space endoscopy rapidly emerged as a minimally invasive alternative to conventional surgery. Many studies discovered that this technique is safe and effective with excellent outcomes. Our review focused on the indications, techniques, clinical management, and adverse events of submucosal tunneling techniques for tumor resection.

Advances in endoscopic resection: a review of endoscopic submucosal dissection (ESD), endoscopic full thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER)

Subepithelial lesions are often detected incidentally in patients undergoing an endoscopy. They are common tumors of the gastrointestinal (GI) tract which can originate from different layers of the GI tract wall. These lesions can be further classified based on GI layer of origin and unique histochemical staining. While most are benign and asymptomatic, some of these lesions have malignant potential with distant metastases. However, current diagnostic modalities including endoscopy with biopsy or endoscopic ultrasound with fine needle aspiration are not always reliable. In addition, management of these lesions has historically involved surgical resection via open or laparoscopic approaches. In recent years, with advancement in endoscopic techniques and improvement in endoscopists' skills, less invasive procedures such as endoscopic submucosal dissection (ESD), endoscopic full thickness resection (EFTR) and submucosal tunneling endoscopic resection (STER) have been developed and now are being used by endoscopists worldwide. Upon reviewing the literature, multiple studies have shown the advantages of these endoscopic techniques when compared with surgical treatment. As a result, there has been a dramatic shift towards minimally invasive endoscopic procedures for the management of these subepithelial lesions. In this review article, we will discuss these endoscopic resection techniques in detail, their safety and efficacy, as well as comparison studies to other therapeutic modalities.

Efficacy and safety of submucosal tunneling endoscopic resection for gastric submucosal tumors: a systematic review and meta-analysis

INTRODUCTION

submucosal tunneling endoscopic resection (STER) can be an effective treatment for submucosal tumors (SMTs) in the esophagus and cardia. However, STER may be more difficult to perform in the stomach than in the esophagus due to special anatomical and physiological features. The feasibility of STER to remove gastric STMs has not been systematically investigated. Therefore, this meta-analysis aimed to evaluate the safety and efficacy of STER for gastric SMTs.

MATERIAL AND METHODS

a comprehensive literature search of the Medline, Embase, PubMed, and Cochrane Library databases was conducted. Complete resection and en-bloc resection rates were considered as the primary outcome measures. The secondary outcome measure was the pooled estimate of complications.

RESULTS

nine studies including 301 patients with 305 lesions were finally included. The pooled estimate of en-bloc resections was 95.1 % (95 % CI: 88.9-97.9 %), Cochran's Q-test, p = 0.151, and the weighted pooled rate (WPR) for complete resection was 97.9 % (95 % CI: 93.6-99.3 %), Cochran's Q-test, p = 0.778. In addition, the pooled estimate of gas-related complications was 8.7 % (95 % CI: 4.6-15.9 %), Cochran's Q-test, p = 0.057. The pooled estimate for mucosal laceration was 4.2 % (95 % CI: 2.2-7.9 %), Cochran's Q-test, p = 0.572. The pooled estimate for delayed bleeding was 2.1 % (95 % CI: 0.9-4.8 %), Cochran's Q-test, p = 0.985. The pooled estimate of inflammation-related complications was 8.6 % (95 % CI: 5.2-13.9 %), Cochran's Q-test, p = 0.308.

CONCLUSION

STER is an effective and safe technique for removing gastric SMTs with low complications, and complications, when encountered, can be treated conservatively.

Principles of Intramural Surgery

Intramural surgery is a minimally invasive surgical technique based on flexible endoscopy. The first step involves the initial mucosal incision for entry point. Then a submucosal tunnel is dissected to the site of the target anatomy. The procedure performed may include myotomy or lesion removal. When complete, the initial mucosal incision is closed. This technique separates the mucosal flap from the surgical site, minimizing the risk of full-thickness perforation and gastrointestinal leakage. Peroral endoscopic myotomy is the most studied application of intramural surgery but other procedures have emerged. This article explores principles of intramural surgery and summarizes its applications.

A History of Flexible Gastrointestinal Endoscopy

Surgeons have been involved, since the beginning, in the development and evolution of endoscopy. They have been instrumental in developing new methods and have been actively involved in most of the therapeutic applications. The continued evolution of endoscopic technique is inevitable and will involve the integration of new technology with innovative thinking.

Endoscopic full thickness resection versus submucosal tunneling endoscopic resection for removal of submucosal tumors: a review article

Submucosal tumors (SMT) are protuberant lesions with intact mucosa that have a wide differential. These lesions may be removed by standard polypectomy, endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), or surgically. However, in lesions that arise from the muscularis propria, full thickness resection is recommended. This can be completed using either endoscopic full thickness resection (EFTR) or submucosal tunneling endoscopic resection (STER). EFTR can be accomplished by completing a full thickness resection followed by defect closure or by securing gastrointestinal wall patency before resection. STER is an option that first creates a mucosal dissection proximal to the lesion to allow a submucosal tunnel to be created. Using this tunnel, the lesion may be resected. When comparing STER to EFTR, there was no significant difference when evaluating tumor size, operation time, rate of complications, or en bloc resection rate. However, suture time, amount of clips used, and overall hospital stay were decreased in STER. With these differences, EFTR may be more efficacious in certain parts of the gastrointestinal tract where a submucosal tunnel is harder to accomplish.

2007-2019: a "Third"-Space Odyssey in the Endoscopic Management of Gastrointestinal Tract Diseases

PURPOSE OF REVIEW

The main scope of this review article is to introduce readers to the innovative field of third-space endoscopy and offer a closer look at its history, milestones, and procedure spectrum while discussing ongoing and future challenges arising from its increasing adoption worldwide.

RECENT FINDINGS

Over the past few years, third-space endoscopy has been utilized in various diagnostic and interventional procedures performed throughout the gastrointestinal tract: obliteration of Zenker's diverticulum, myotomy for achalasia, gastroparesis or Hirschsprung's disease, biopsy or removal of subepithelial tumors, stricture management, post-per-oral endoscopic myotomy endoscopic fundoplication, and mediastino-, thoraco-, and peritoneoscopy. Third-space endoscopic interventions have revolutionized the management of esophageal motility disorders, gastroparesis, and gastrointestinal tract subepithelial tumors. Despite the high efficacy and safety of such interventions, some common (e.g., the high level of necessary endoscopic skill) and unique for each procedure (e.g., post-procedure gastroesophageal reflux or poor outcomes in patient subgroups) challenges still remain. Through a dedicated endoscopic training, a rigorous pre-procedure patient evaluation and selection, and the application of modified or new techniques, challenges can be overcome thus establishing existing procedures and paving the way for additional breakthroughs in the field of third-space endoscopy.

Efficacy and safety of submucosal tunneling endoscopic resection for upper gastrointestinal submucosal tumors with more than 1-year' follow-up: a systematic review and meta-analysis

Objectives: Submucosal tunneling endoscopic resection (STER) is a novel therapeutic approach for upper gastrointestinal submucosal tumors (SMTs) especially for tumors originating from the muscularis propria layer. Presently, several studies have reported the efficacy and safety of STER for SMTs. Therefore, we conducted this study to review the clinical outcomes of STER with more than 1-year' follow-up duration. Materials and methods: Medline, Embase and Cochrane databases were searched on November 2018 to identify studies reporting STER for SMTs. Weighted pooled rates were calculated for en bloc resection, complete resection and adverse event (AE). Risk ratios (RR) were calculated and pooled to compare STER with thoracoscopic enucleation (TE). Results: A total of 701 patients with 728 lesions from 12 original studies were review. Pooled WPR for en bloc resection of STER was 86.3% (95% CI: 74.5-93.1%), (I²=82.5). Pooled WPR for complete resection of STER was 97.7% (95% CI: 92.8-99.3%), (I²=77.6). WPR for AE was 18.3% (95% CI: 9.7-31.6%), (I²=90.6%). Two studies with 292 patients compared the performance of STER with TE. Pooled RR for en bloc resection was 1.02 (95% CI: 0.95-1.09). Pooled RR for complete resection was 1.0 (95% CI: 0.98-1.03). Pooled RR for AE was 0.82 (95% CI: 0.33-2.05). Conclusions: Our study showed that STER has relatively long-term efficacy for treating upper gastrointestinal SMTs, and the incidence of AE was not low for STER, but all of them can be managed conservatively.

Consensus on the digestive endoscopic tunnel technique

With the digestive endoscopic tunnel technique (DETT), many diseases that previously would have been treated by surgery are now endoscopically curable by establishing a submucosal tunnel between the mucosa and muscularis propria (MP). Through the tunnel, endoscopic diagnosis or treatment is performed for lesions in the mucosa, in the MP, and even outside the gastrointestinal (GI) tract. At present, the tunnel technique application range covers the following: (1) Treatment of lesions originating from the mucosal layer, e.g., endoscopic submucosal tunnel dissection for oesophageal large or circular early-stage cancer or precancerosis; (2) treatment of lesions from the MP layer, per-oral endoscopic myotomy, submucosal tunnelling endoscopic resection, etc.; and (3) diagnosis and treatment of lesions outside the GI tract, such as resection of lymph nodes and benign tumour excision in the mediastinum or abdominal cavity. With the increasing number of DETTs performed worldwide, endoscopic tunnel therapeutics, which is based on DETT, has been gradually developed and optimized. However, there is not yet an expert consensus on DETT to regulate its indications, contraindications, surgical procedure, and postoperative treatment. The International DETT Alliance signed up this consensus to standardize the procedures of DETT. In this consensus, we describe the definition, mechanism, and significance of DETT, prevention of infection and concepts of DETT-associated complications, methods to establish a submucosal tunnel, and application of DETT for lesions in the mucosa, in the MP and outside the GI tract (indications and contraindications, procedures, pre- and postoperative treatments, effectiveness, complications and treatments, and a comparison between DETT and other operations).

Submucosal tunneling endoscopic resection: An effective and safe therapy for upper gastrointestinal submucosal tumors originating from the muscularis propria layer

AIM

To evaluate the effectiveness and safety of submucosal tunneling endoscopic resection (STER) and compare its outcomes in esophageal and cardial submucosal tumors (SMTs) of the muscularis propria (MP) layer.

METHODS

From May 2012 to November 2017, 173 consecutive patients with upper gastrointestinal (GI) SMTs of the MP layer underwent STER. Overall, 165 patients were included, and 8 were excluded. The baseline characteristics of the patients and SMTs were recorded. The en bloc resection rate, complete resection rate, residual rate, and recurrence rate were calculated to evaluate the effectiveness of STER, and the complication rate was recorded to evaluate its safety. Effectiveness and safety outcomes were compared between esophageal and cardial SMTs.

RESULTS

One hundred and twelve men and 53 women with a mean age of 46.9 ± 10.8 years were included. The mean tumor size was 22.6 ± 13.6 mm. Eleven SMTs were located in the upper esophagus (6.7%), 49 in the middle esophagus (29.7%), 46 in the lower esophagus (27.9%), and 59 in the cardia (35.7%). Irregular lesions accounted for 48.5% of all lesions. STER achieved an en bloc resection rate of 78.7% (128/165) for GI SMTs with an overall complication rate of 21.2% (35/165). All complications resolved without intervention or were treated conservatively without the need for surgery. The en bloc resection rates of esophageal and cardial SMTs were 81.1% (86/106) and 72.1% (42/59), respectively (P = 0.142), and the complication rates were 19.8% (21/106) and 23.7% (14/59), respectively, (P = 0.555). The most common complications for esophageal SMTs were gas-related complications and fever, while mucosal injury was the most common for cardial SMTs.

CONCLUSION

STER is an effective and safe therapy for GI SMTs of the MP layer. Its effectiveness and safety are comparable between SMTs of the esophagus and cardia.

A comparison of submucosal tunneling endoscopic resection and endoscopic full-thickness resection for gastric fundus submucosal tumors

AIM

Both submucosal tunneling endoscopic resection (STER) and endoscopic full-thickness resection (EFTR) are effective methods for gastric fundus submucosal tumors (SMTs). However, there is little data that compares the two methods. The aim of this study was to compare the safety and efficacy of STER and EFTR for the treatment of SMTs in the gastric fundus.

METHODS

Clinical data was retrospectively collected from patients with gastric fundus SMTs who underwent STER or EFTR at our hospital from April 2011 to May 2016. Epidemiological data (gender, age), tumor size, procedure-related parameters, complications, postoperative hospital stay, cost and follow-up data were compared.

RESULTS

A total of 43 patients were enrolled: 15 underwent STER and the remaining 28 cases underwent EFTR. There were no significant differences between the two groups with regard to gender, age, tumor size, en bloc resection rate, operation time, pathohistological results and cost (p > 0.05). However, patients who underwent EFTR had a longer suture time, required a larger number of clips for closure and a prolonged postoperative hospital stay (p < 0.05). No recurrence was noted in either the STER or the EFTR group during a mean follow-up of 12.1 and 22.8 months, respectively.

CONCLUSIONS

The treatment efficacy of STER and EFTR for the treatment of gastric fundus SMTs was comparable. However, STER has some advantages over EFTR in terms of suture time, the number of clips required for closure and postoperative hospital stay.

Submucosal Tunneling Endoscopic Resection for the Treatment of Gastrointestinal Submucosal Tumors Originating from the Muscularis Propria Layer

Surgical resection and endoscopic resection comprise two alternative options for the treatment of submucosal tumors (SMTs) originating from the muscularis propria (MP) layer. Endoscopic resection is minimally invasive compared with surgical resection. Conventional non-tunneling techniques, such as endoscopic submucosal dissection (ESD), endoscopic submucosal excavation (ESE), and endoscopic full-thickness resection (EFR) have been demonstrated to be safe and effective. However, these techniques fail to maintain the integrity of the mucosa and induce high risk of perforation, infection, and postoperative strictures. Submucosal tunneling endoscopic resection (STER) is a novel surgical technique that can maintain the integrity of the mucosa by establishing a tunnel between the submucosal and the MP layers. STER has been proven to be effective and safe for the treatment of SMTs. Currently, STER has become a standard treatment for gastrointestinal (GI) SMTs originating from the MP layer, notably in China. In the present review, we describe the indications, procedures, postoperative care, efficacy and safety outcomes, and future perspectives of STER for GI SMTs originating from the MP layer.

The Advantage of an Endoscopic Submucosal Tunneling Technique for Rectal Carcinoid Tumors

Endoscopic treatment can be a curative option for small carcinoid tumors with an extremely low risk of metastasis. Since most carcinoid tumors are characterized by a specific growth pattern in the submucosal (SM) layer, specialized endoscopic techniques for deeper resection to achieve clear vertical margins are needed. The endoscopic submucosal dissection (ESD) method in the SM space is superior to conventional endoscopic mucosal resection. However, the standard ESD technique sometimes fails to provide complete deep SM dissection due to insufficient SM lifting. Here, to resolve this problem, we describe our initial experience with an endoscopic SM tunneling technique that is effective for treating rectal carcinoid tumors.

Factors affecting the effectiveness and safety of submucosal tunneling endoscopic resection for esophageal submucosal tumors originating from the muscularis propria layer

BACKGROUND AND AIMS

Submucosal tunneling endoscopic resection (STER) has been proved to be effective and safe for esophageal submucosal tumors (SMTs) originating from the muscularis propria (MP) layer. This study was aimed to further evaluate the effectiveness, safety, and influencing factors especially the types of mucosal incision of STER in a larger population.

METHODS

A total of 89 patients undergoing STER with esophageal SMTs were retrospectively enrolled in this study from May 2012 to November 2016. Clinicopathological, endoscopic, and adverse events (AEs) data were collected and analyzed. Different incision methods were compared to evaluate the optimum incision method.

RESULTS

There were 27 females and 62 males with mean age of 46.5 ± 10.3 years. The medium size of the tumors was 16.0 mm (ranging 10.0-60.0 mm). Inverted T incisions were made in 29 (32.6%) patients, transverse incisions in 12 (13.5%) while longitudinal incisions in 48 (53.9%). En bloc resection was achieved in 70 (78.7%) patients. The residual rate was 1.1% (1/89), and no recurrence was noted even after piecemeal resection. The rate of AEs was 21.3% (19/89), and all of the AEs were cured without intervention or treated conservatively without the need for surgery. The en bloc resection rate was comparable among the three incision groups (P = 0.868); however, the incidence of AEs in the inverted T incision was lower than that in the longitudinal incision (P = 0.003). Fewer clips were used in the inverted T incision group than in the transverse incision group (P = 0.003).

CONCLUSIONS

Although STER failed to achieve en bloc resection in 21.3% patients, it was still an effective therapy owing to low residual rate and no recurrence rate after piecemeal resection. STER was safe with no severe AEs; however, minor AEs were common. Inverted T incision seems to be the optimum entry point.

Technological review on endoscopic submucosal dissection: available equipment, recent developments and emerging techniques

Endoscopic submucosal dissection (ESD) is widely practiced in Japan and the Eastern World and is rapidly expanding in western countries for the management of early malignancies of the upper and lower gastrointestinal tube. In addition, novel therapeutic applications deriving from ESD have emerged including the treatment of achalasia, of submucosal tumors, of diverticula, of strictures and of reflux disease. An ESD procedure necessitates not only skills and specific training, but also familiarization with a vast spectrum of devices (endoscopes, high-frequency generators and their settings, endoknives, hoods, irrigation devices) and techniques (such as countertraction, artificial ulcer closure), that render the procedure faster, more efficient and safer. This technological article gives an overview on current and novel equipment for an ESD and associated techniques.

Current Status of Exposed Endoscopic Full-Thickness Resection and Further Development of Non-Exposed Endoscopic Full-Thickness Resection

Endoscopic full-thickness resection (EFTR) is a procedure that makes it possible to access the lesions that are on the wall of the digestive tract via the shortest distance through the mouth. Because of the ultra-minimal invasive nature of the treatment, pure EFTR is a highly promising surgical procedure that allows the radical excision of full-thickness layers of digestive tract tumors using only a flexible endoscope. There are 2 types of EFTR methods: exposed and non-exposed. Considering the risks of contracting infection and intraperitoneal dissemination of tumor cells, non-exposed EFTR is an ideal method. However, a number of issues remain unresolved, including the method for performing a full-thickness suture under endoscopic view and the challenge of securing the operating field in the case of gastrointestinal tract collapse. Moreover, advances in the development of equipment such as full-thickness suturing devices would be helpful to make this therapeutic procedure the most minimally invasive endoscopic surgery ever.

Comparison between submucosal tunneling endoscopic resection and endoscopic full-thickness resection for gastric stromal tumors originating from the muscularis propria layer

BACKGROUND

Both submucosal tunneling endoscopic resection (STER) and endoscopic full-thickness resection (EFTR) are effective method for treating gastric gastrointestinal stromal tumors (GISTs); however, little is known about the comparison between STER and EFTR. The aim of the study was to compare the safety and efficacy of STER and EFTR for treating gastric GIST.

METHODS

We retrospectively collected the clinical data about patients with gastric GISTs who received STER or EFTR at our hospital from April 2011 to June 2016. Epidemiological data (gender, age), tumor size, procedure-related parameters, complications, length of stay, cost and follow-up data were compared between STER and EFTR.

RESULTS

A total of 52 patients were enrolled, and 20 of them received STER, while the other 32 cases received EFTR. There was no significant difference between the two groups in terms of gender, age, concomitant diseases, tumor size, en bloc resection rate, operation time, complications, pathohistological grade of GIST, hospital stay and cost (P > 0.05). However, patients who received EFTR had a longer suture time and needed more clips to close the gastric-wall defect (STER vs EFTR, 291.5 ± 68.7 vs 380.6 ± 96.9s and 6.0 ± 1.2 vs 7.6 ± 1.6, P < 0.05). No recurrence was noted in the STER and EFTR groups during a mean follow-up of 10.9 and 23.8 months, respectively.

CONCLUSIONS

The treatment efficacy between STER and EFTR for treating gastric GISTs was comparable, and a large-scale, randomized study is necessary for a more confirmed conclusion.

Percutaneous transgastric endoscopic tube ileostomy in a porcine survival model

AIM

To introduce natural orifice transgastric endoscopic surgery (NOTES) tube ileostomy using pelvis-directed submucosal tunneling endoscopic gastrostomy and endoscopic tube ileostomy.

METHODS

Six live pigs (three each in the non-survival and survival groups) were used. A double-channeled therapeutic endoscope was introduced perorally into the stomach. A gastrostomy was made using a 2-cm transversal mucosal incision following the creation of a 5-cm longitudinal pelvis-directed submucosal tunnel. The pneumoperitoneum was established via the endoscope. In the initial three operations of the series, a laparoscope was transumbilically inserted for guiding the tunnel direction, intraperitoneal spatial orientation and distal ileum identification. Endoscopic tube ileostomy was conducted by adopting an introducer method and using a Percutaneous Endoscopic Gastrostomy Catheter Kit equipped with the Loop Fixture. The distal tip of the 15 Fr catheter was placed toward the proximal limb of the ileum to optimize intestinal content drainage. Finally, the tunnel entrance of the gastrostomy was closed using nylon endoloops with the aid of a twin grasper. The gross and histopathological integrity of gastrostomy closure and the abdominal wall-ileum stoma tract formation were assessed 1 wk after the operation.

RESULTS

Transgastric endoscopic tube ileostomy was successful in all six pigs, without major bleeding. The mean operating time was 71 min (range: 60-110 min). There were no intraoperative complications or hemodynamic instability. The post-mortem, which was conducted 1-wk postoperatively, showed complete healing of the gastrostomy and adequate stoma tract formation of ileostomy.

CONCLUSION

Transgastric endoscopic tube ileostomy is technically feasible and reproducible in an animal model, and this technique is worthy of further improvement.