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

Novel Sequence of Endoscopic Therapy for the Management of Colonic Adenocarcinoma and Surrounding Adenoma

An 80-year-old man with a history of an orthotopic heart transplant was found to have a 25 × 40 mm centrally ulcerated mass at the hepatic flexure during evaluation of anemia. Owing to comorbidities, the patient was deemed to be a poor surgical candidate and was referred to the advanced endoscopy team to explore palliative and potentially curative options. We present a novel sequence of intervention involving full-thickness resection with subsequent morcellation clean-up to achieve complete endoscopic removal of a neoplastic lesion.

The factors influencing the accuracy of pre-operative endoscopic ultrasonography assessment in endoscopic treatments for gastrointestinal tumors

BACKGROUND

This retrospective study aimed to evaluate the factors influencing the accuracy of Endoscopic Ultrasonography (EUS) as a preoperative assessment for gastrointestinal tumors.

METHODS

A total of 261 patients with 264 gastrointestinal tumors were enrolled in the study. The parameters of the gastrointestinal lesions examined under EUS and their pathology were recorded and analyzed.

RESULTS

The accuracy of EUS for detecting intramucosal lesions and subepithelial lesions (SELs) were 83.6% and 91.4%, respectively. One hundred and ninety-four (73.5%) lesions originated from the mucous layer, as determined by pre-operation EUS examinations. The accuracy of EUS in predicting the correct T stage for intramucosal lesions in the gastric region, esophagus, and colorectum was 77%, 71.8%, and 84.6%, respectively. According to the Paris endoscopic classification, the distribution of macroscopic patterns was different between the EUS-pathology conformity and nonconformity groups (p = 0.018). In the nonconformity group, 48.6% of erosive lesions were classified as 0-IIc, 0-IIa + IIc, 0-IIc + IIa or 0-III macroscopic patterns compared with 26% patients in the conformity group (p = 0.025). Univariate analyses demonstrated that ulcerative lesions (OR = 7.516, 95% Confidence Interval [CI] 2.574-21.952, p < 0.001), location at the cardia of the stomach (OR = 3.619, 95%CI 1.076-12.168, p = 0.038), malignant tumor (OR = 2.920, 95%CI 1.339-6.368, p = 0.007) were significantly associated with EUS inaccuracy. Multivariate logistic regression analyses showed that ulcer was an independent risk factor associated with EUS inaccuracy, with odds ratios of 5.094 (95% CI: 1.641-15.807, p = 0.005).

CONCLUSIONS

Our findings suggested that EUS is a reliable and easy-to-use diagnostic tool in decision-making regarding appropriate endoscopic treatment for gastrointestinal tumors. However, the diagnostic accuracy of EUS appeared questionable in the presence of ulceration.

Efficacy and Safety of Small Bowel Submucosal Tumors Treated by Endoscopic Submucosal Dissection or Endoscopic Full-thickness Resection During Single-balloon Enteroscopy: Prospective Data From a Single-center Study

BACKGROUND AND OBJECTIVES

Single-balloon enteroscopy (SBE) is a safe and effective modality for the diagnosis and therapeutic treatment of small bowel disorders. However, the efficacy and safety of treating small bowel submucosal tumors (SMTs) with endoscopic submucosal dissection (ESD) or endoscopic full-thickness resection (EFTR) during SBE have not been determined. Hence, the primary aim of this study was to prospectively evaluate the therapeutic yield of SBE in patients with SMTs.

PATIENTS AND METHODS

Twenty-one patients with SMTs were enrolled in this study. Regarding the sex distribution, there were 12 men (57.1%) and 9 women (42.9%). Regarding the age distribution, 42.9% of the patients were 60 years old or older and 57.1% of the patients were under 60 years old. The preoperative characteristics of SMTs were summarized and analyzed, the complete resection incidence of SMTs was determined, and the incidence of postoperative complications was collected. ESD-related and EFTR-related complications and the duration of follow-up after leaving hospital were also summarized and analyzed. The efficacy and safety of SMTs treated by ESD or EFTR during SBE were calculated as percentages.

RESULTS

Among the 21 patients, 10 (47.6%) underwent EFTR and 11 (52.4%) underwent ESD. The mean diameter of SMTs was 113.50 mm (range: 80 to 160 mm). Anterograde and retrograde SBE were conducted in 11 and 10 patients, respectively. The mean follow-up time was 49.3 days (range: 6.0 to 129 d). The complete resection rate of SMTs was 100%. The complete suture rate of SMTs wound was 100%. The SMTs pathology of all patients showed that the margin-negative (R0) resection was 100%. The incidence of physical discomfort complications (ie, infection/fever, abdominal pain, and abdominal distension) of ESD and EFTR was 5 (23.8%) on day 1, 1 (4.8%) on day 2, and 1 (4.8%) on day 3 after operation. Only 1 (4.8%) patient with EFTR had abdominal pain on the sixth day after leaving hospital, and the visual analog scale/score was 1 point, meaning the pain was easily tolerated by the patient. Twenty (95.2%) patients had no abdominal discomfort after leaving hospital. No patients needed additional surgery because of complications after ESD or EFTR during SBE.

CONCLUSIONS

This preliminary study showed that SMTs can be safely and effectively treated by ESD or EFTR during SBE, particularly SMTs <160 mm in diameter.

Endoscopic Full Thickness Resection: A Systematic Review

Background Endoscopic full thickness resection (EFTR) is an emerging therapeutic option for resecting subepithelial lesions (SELs) and epithelial neoplasms. We aimed to systematically review the techniques, applications, outcomes, and complications of EFTR.

Methods A systematic literature search was performed using PubMed. All relevant original research articles involving EFTR were included for the review along with case report/series describing novel/rare techniques from 2001 to February 2022.

Results After screening 7,739 citations, finally 141 references were included. Non-exposed EFTR has lower probability of peritoneal contamination or tumor seeding compared with exposed EFTR. Among exposed EFTR, tunneled variety is associated with lower risk of peritoneal seeding or contamination compared with non-tunneled approach. Closure techniques involve though the scope (TTS) clips, loop and clips, over the scope clips (OTSC), full thickness resection device (FTRD), and endoscopic suturing/plicating/stapling devices. The indications of EFTR range from esophagus to rectum and include SELs arising from muscularis propria (MP), non-lifting adenoma, recurrent adenoma, and even early gastric cancer (EGC) or superficial colorectal carcinoma. Other indications include difficult locations (involving appendicular orifice or diverticulum) and full thickness biopsy for motility disorders. The main limitation of FTRD is feasibility in smaller lesions (<20–25 mm), which can be circumvented by hybrid EFTR techniques. Oncologic resection with lymphadencetomy for superficial GI malignancy can be accomplished by hybrid natural orifice transluminal endoscopic surgery (NOTES) combining EFTR and NOTES. Bleeding, perforation, appendicitis, enterocolonic fistula, FTRD malfunction, peritoneal tumor seeding, and contamination are among various adverse events. Post OTSC artifacts need to be differentiated from recurrent/residual lesions to avoid re-FTRD/surgery.

Conclusion EFTR is safe and effective therapeutic option for SELs, recurrent and non-lifting adenomas, tumors in difficult locations and selected cases of superficial GI carcinoma.

Endoscopic Full-Thickness Resection for Colorectal Lesions: A Systematic Review and Meta-Analysis

INTRODUCTION

Endoscopic full-thickness resection (EFTR) with an over-the-scope full-thickness resection device is a relatively new technique for the resection of colorectal lesions. Multiple centers have published the results of case series and observational cohorts regarding the use of this technique for managing difficult polyps. This study aims to aggregate the results of these studies to determine the effectiveness and safety of this technique in the resection of these technically challenging colonic lesions.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched. Articles were included if they reported technical success rate for EFTR of colonic lesions. The primary outcome was technical success rate and secondary outcomes included rate of R0 resection and overall 30-d morbidity. DerSimonian and Laird random-effects meta-analysis of proportions was used to generate effect sizes for pooled outcomes.

RESULTS

From 2211 citations, 21 studies with 1539 patients (mean age 67.2 y, 39.5% female) undergoing 1551 procedures were included. Difficult to resect benign lesions were the most commonly excised lesions (hyperplastic: 35.9%; adenomas: 30.2%), followed by T1 adenocarcinomas (25.6%) and neuroendocrine tumors (6.1%). Technical success rate was 89% (95% confidence interval [CI] 87-92), and R0 resection rate was 79% (95% CI 76-82). Mean procedure time was 53.5 min and mean specimen size was 17.5 mm. Overall 30-d morbidity was 11% (95% CI 7-13), and incidences of perforation and postpolypectomy bleeding were 2% (95% CI 1-2) and 5% (95% CI 3-7), respectively. Lesion recurrence at 3-mo follow-up was 8%.

CONCLUSIONS

EFTR requires further large sample size, comparative studies with reporting of long-term oncologic data. However, preliminary findings indicate that it is a safe and effective technique with high rates of technical success and acceptable rates of R0 resection when employed by experienced endoscopists for high-risk colonic lesions.

Colon Sparing Endoscopic Full-Thickness Resection for Advanced Colorectal Lesions: Is It Time for Global Adoption?

The majority of colon lesions are <10 mm in size and are easily resected by endoscopists with appropriate basic training. Lesions ≥10 mm in size are difficult to remove technically and are associated with higher rates of incomplete resection. Currently, the main endoscopic approaches include endoscopic mucosal resection (EMR) for lesions without submucosal invasion, and endoscopic submucosal dissection (ESD) for relatively larger lesions involving the superficial submucosal layer. Both of these approaches have limitations, EMR cannot reliably ensure complete resection for larger tumors and recurrence is a key limitation. ESD reliably provides complete resection and an accurate pathological diagnosis but is associated with risk such as perforation or bleeding. In addition, both EMR and ESD may be ineffective in treating subepithelial lesions that extend beyond the submucosa. Endoscopic full-thickness resection (EFTR) is an emerging innovative endoscopic therapy which was developed to overcome the limitations of EMR and ESD. Advantages include enabling a transmural resection, complete resection of complex colorectal lesions involving the mucosa to the muscularis propria. Recent studies comparing EFTR with current resection techniques and radical surgery for relatively complicated and larger lesion have provided promising results. If the current trajectory of research and development is maintained, EFTR will likely to become a strong contender as an alternative standard of care for advanced colonic lesions. In the current study we aimed to address this need, and highlighted the areas of future research, while stressing the need for multinational collaboration provide the steppingstone(s) needed to bring EFTR to the mainstream.

New Applications for Submucosal Tunneling in Third Space Endoscopy: A Comprehensive Review

Third space endoscopy (TSE), a type of natural orifice transluminal endoscopic surgery, was first introduced a decade ago, and since then, has revolutionized the field of therapeutic endoscopy. TSE involves tunneling into the submucosal space between the intestinal mucosa and the muscularis propria. By accessing this "third space," endoscopists can perform minimally invasive myotomies, resections, and dissections while maintaining the mucosa and preventing full-thickness perforation. TSE procedures can be used to treat motility disorders as well as neoplasms throughout the gastrointestinal tract, which were traditionally conditions that would require open or laparoscopic surgery. The main TSE procedures include peroral endoscopic myotomy, gastric peroral endoscopic myotomy, Zenker peroral endoscopic myotomy, submucosal tunneling for endoscopic resection, endoscopic submucosal tunnel dissection, peroral endoscopic tunneling for restoration of the esophagus, and per-rectal endoscopic myotomy. Some of those procedures have now been accepted as viable alternative to surgical techniques due to their limited invasiveness, safety and cost. This review will explore the different techniques recently added to our arsenal while describing their potential efficacy and limitations.

State of the Art in Endoscopic Therapy for the Management of Gastroenteropancreatic Neuroendocrine Tumors

OPINION STATEMENT

Gastroenteropancreatic neuroendocrine neoplasms (GEP NENs) comprise a heterogeneous group of slow growing tumors arising from the neuroendocrine cells of the gastrointestinal (GI) tract. Although they are considered relatively rare, their incidence is rising and it is believed that the more frequent use of endoscopy and imaging studies have at least in part contributed to the increased diagnosis especially of localized neoplasms. The management of these neoplasms should be guided by a multidisciplinary NEN team following appropriate staging investigations. Localized neoplasms of the GI tract may be suitable for endoscopic therapy, while patients with pancreatic NENs, unsuitable for surgery, should be considered for endoscopic ultrasound (EUS)-guided ablation. In this review, we discuss the evidence regarding endoscopic resection of luminal NENs and EUS-guided therapy of pancreatic NENs. The efficacy, safety, and other longer-term outcomes of these techniques are summarized. In conclusion, this review of endoscopic therapies for localized NENs may be a useful guide for NEN clinicians and endoscopists who are considering these therapeutic options for the management of focal GEP NENs.

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.

Risk Factors for Fever After Esophageal Endoscopic Submucosal Dissection and Its Derived Technique

Background

Fever is one of the postoperative adverse events of endoscopic submucosal dissection and its derived technique, but the probability and risk factors of postoperative fever are still unclear. The aim of the current study was to investigate the incidence and risk factors of postoperative fever after esophageal lesion removal.

Methods

We conducted a retrospective study of 446 patients who underwent esophageal endoscopic submucosal dissection and its derived technique between January 2014 and January 2020. Cases included in this study were divided into fever and non-fever groups.

Results

Postoperative fever developed in 135 patients (30.3%). The median (range) highest fever temperature was 38 (37.8–38.4)°C, the median (range) duration of fever was 1 (1–2) day, and 127 (94.1%) patients developed fever within 24 h after operation. Through logistic regression analysis, factors associated with postoperative fever were age (OR: 1.740, 95% CI: 1.005–3.013, p = 0.048), lesion size (OR: 2.007, 95% CI: 1.198–3.362, p = 0.008), operation time (OR: 3.007, 95% CI: 1.756–5.147, p < 0.001) and nasogastric tube placement (OR: 1.881, 95% CI: 1.165–3.037, p = 0.010), while prophylactic antibiotics (OR: 0.181, 95% CI: 0.082–0.401, p < 0.001) were negatively associated with fever.

Conclusions

Age ≥52 years old, lesion size ≥19 mm, operation time ≥37 min, and nasogastric tube placement are risk factors for postoperative fever after esophageal endoscopic submucosal dissection and its derived technique, prophylactic antibiotic use after operation may help reduce fever rate. Attention should be paid to such patients to minimize the risk of postoperative fever.

The therapeutic effect of the digestive endoscopy tunneling technique on upper gastrointestinal muscularis propria tumors

OBJECTIVE

To analyze the therapeutic effect of digestive endoscopy tunneling technology on upper gastrointestinal muscularis propria tumors.

METHODS

A total of 120 patients with upper gastrointestinal tumors in the muscularis propria treated in our hospital in the past two years were recruited as the study cohort. They were treated using the digestive endoscopic tunneling technique, specifically, endoscopic submucosal tunneling tumor resections, and their clinical data, surgical conditions, pathological results, incidences of complications (CR), and anxiety scores were recorded. A postoperative follow-up was conducted on the patients.

RESULTS

A total of 122 tumors were removed from 120 patients, including two patients who had two tumors each. The largest diameter among the tumors was 4.2 cm, and the average diameter was (2.01±1.56) cm. There were 86 tumors located in the superficial layer of the muscularis propria and 36 pieces in the deep layer. No significant differences were found in the patients' clinical data (P > 0.05). The 120 patients all successfully completed their operations. The operation times ranged between 26 min and 158 min. The en bloc resection rate was 95.8%, and the average postoperative hospital stay was 3.8 days. The pathological diagnoses showed that there were 72 leiomyomas, accounting for 59.0% of the total, and 44 stromal tumors, accounting for 36.1%. There were 2 glomus tumor cases, accounting for 1.6%, and 4 nerve sheath tumor cases, accounting for 3.3%. No patient had delayed gastrointestinal bleeding or mucosal perforations. The probability of subcutaneous emphysema and pneumothorax was 1.7%, the probability of pneumoperitoneum was 0.8%, the probability of retrosternal pain was 10.0%, and the total incidence of CR was 14.2%. No tumor recurrence or residual phenomenon was found at the 3, 6, or 12 month follow ups after the treatment, and the patients' satisfaction rate was as high as 98.3%. Their anxiety scores also decreased significantly over time (P < 0.001).

CONCLUSION

Digestive endoscopy tunnel technology can effectively improve the surgical success rate of patients with upper gastrointestinal muscularis propria tumors, reduce the probability of CR, and reduce patients' psychological pressure. It has significant effects in the treatment of upper gastrointestinal muscularis propria tumors and should be widely applied in clinical practice.

Advancing flexible endoscopy to natural orifice transluminal endoscopic surgery

PURPOSE OF REVIEW

This review is an update on the recent advancements and clinical applications of flexible endoscopy in the context of natural orifice translumenal endoscopic surgery (NOTES). We focus on recent developments in gastrointestinal luminal and transluminal NOTES.

RECENT FINDINGS

NOTES has evolved from a hybrid approach utilizing a laparoscopic assistant to pure NOTES without laparoscopic assistance. Current experimental and clinical studies focus on the implementation of new minimally invasive approaches as well as on the training in the use of these procedures. In recent years, flexible endoscopic-NOTES and endoluminal surgery have increasingly reported favorable results in preclinical and experimental settings using flexible endoscopic cholecystectomy, cholecystolithotomy, and appendectomy. Additionally, flexible endoscopic lymphadenectomy and thyroidectomy are among the new interventions that are opening new frontiers for endoscopists to explore.

SUMMARY

Flexible endoscopy has paved way to new frontiers for endoscopists and surgeons. As the armamentarium of interventional endoscopy increases and the ability of endoscopists to perform advanced interventions safely fosters an inevitable step forward that will involve the integration of new technology with innovative thinking.

A Narrative Review of update in per oral endoscopic myotomy (POEM) and endoscopic esophageal surgery

The field of endoscopic esophageal surgery is based on the concept of natural orifice transluminal endoscopic surgery (NOTES). Submucosal space surgery or third space surgery with the use of flexible endoscopy allows for decreased morbidity and hospital length of stay with equivalent outcomes for patients. In the case of achalasia, per oral endoscopic myotomy (POEM) allows for management of refractory cases in setting of previous Heller Myotomy or in patients whom laparoscopic or thoracoscopic surgery is contraindicated. Lastly, POEM more directly divides circular muscular layer of esophagus without destroying surrounding structures that exist to prevent reflux. The innovations in endoscopic surgery began in the animal lab with experiments in the porcine model to develop a way to access the peritoneal cavity through an entry point in the gastric mucosa. Over the last 10 years, the biggest treatment innovations in endoscopy have focused on management of achalasia with the use of POEM. POEM became possible as technology was developed that revolutionized the use of flexible technology and the methods of mucosal closure. In addition to benign esophageal disease, endoscopic methods improved in management of esophageal malignancy with endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD). The innovations of endoscopic surgery have been developed through the utilization of the submucosal space as a method to ensure adequate closure of the mucosal entry point into the peritoneal cavity. The goal of this review paper is to explore POEM and other techniques in endoscopic esophageal surgery for the management of esophageal diverticulum, submucosal tumors, gastroparesis, and gastrointestinal esophageal reflux disease.

Comparison of Endoscopic Techniques in the Management of Type I Gastric Neuroendocrine Neoplasia: A Systematic Review

BACKGROUND

Endoscopic resection is considered the treatment of choice for type I gastric neuroendocrine neoplasia (gNEN) given its indolent behaviour; however, the favoured endoscopic technique to remove these tumours is not well established.

AIMS

This systematic review is aimed at investigating the best endoscopic management for type I gNEN.

METHODS

PubMed Central/Medline and Scopus were systematically searched for records up to August 31, 2020.

RESULTS

After screening the 675 retrieved records, 6 studies were selected for the final analysis. The main endoscopic resection techniques described were endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Overall, 112 gNENs were removed by EMR and 77 by ESD. Both techniques showed similar results for complete and en bloc resection (97.4% and 98.7%; 92.3% and 96.3% with ESD and EMR, respectively). ESD was associated with a higher rate of complications than EMR (11.7% vs. 5.4%), but this difference was not statistically significant (p = 0.17). The rates of recurrence during follow-up were 18.2% and 11.5% for EMR and ESD, respectively.

CONCLUSIONS

To date, there are no sufficient data showing superiority of a given endoscopic technique over others. Both ESD and EMR seem to be effective in the management of type I gNEN, with a relatively low rate of recurrence.

Peroral endoscopic tumor resection (POET) with preserved mucosa technique for management of upper gastrointestinal tract subepithelial tumors

BACKGROUND

Third space endoscopy technique facilitates therapeutic endoscopy in subepithelial space. This study aimed to investigate peroral endoscopic tumor resection (POET) with preserved mucosa technique for upper gastrointestinal tract subepithelial tumors (UGI-SETs) removal.

METHODS

Between February 2011 and December 2019, consecutive patients with SETs of esophagus and stomach who underwent POET for enlarging size during follow-up, malignant endoscopic ultrasound features or by patient's request were enrolled. Demographic, endoscopic and pathological data were analyzed retrospectively.

RESULTS

Totally 18 esophageal (mean ± SD age, 55.23 ± 4.15 year-old, 38.89% female) and 30 gastric (52.65 ± 2.43 year-old, 53.33% female) SETs in 47 patients (one with both esophageal and gastric lesions) were resected. The mean (± SD) endoscopic/pathological tumor size, procedure time, en-bloc/complete resection rate, and hospital stays of esophageal and gastric SET patients were 12.36 (± 7.89)/11.86 (± 5.67) and 12.57 (± 6.25)/12.35 (± 5.73) mm, 14.86 (± 6.15) and 38.21 (± 15.29) minutes, 88.89%/94.44% and 86.77%/93.30%, and 4.14 (± 0.21) and 4.17 (± 0.20) days, respectively. The overall complication rate was 18.75%, including 6 self-limited fever and 3 pneumoperitoneum relieved by needle puncture. There was no mortality or recurrence reported with mean follow-up period of 23.74 (± 4.12) months.

CONCLUSIONS

POET is a safe and efficient third space endoscopic resection technique for removal of UGI-SETs less than 20 mm. Long term data are warranted to validate these results.

Endoscopic Full Thickness Resection for Gastrointestinal Tumors - Challenges and Solutions

Standard polypectomy, endoscopic mucosal resection, and endoscopic submucosal dissection (ESD) are established techniques for the treatment of gastrointestinal tumors. However, resection of submucosal tumors via ESD often results in low rates of microscopically margin-negative (R0) resection and high rates of perforation. Endoscopic full thickness resection (EFTR) overcomes this adverse event and aids in the therapeutic management of complex tumors.

Multiple techniques for EFTR have been developed, each with its own advantages and disadvantages. Submucosal tunneling and non-exposed techniques are generally preferable, because the layer of overlying intact mucosa reduces the incidence of intraperitoneal contamination by the gastric fluid and dissemination of the tumor cells. However, adoption of EFTR by endoscopists in clinical practice remains low. The major challenge seems to be the technical difficulty in performing laparoscopic and/or endoscopic suturing using the currently available instruments.

We developed a novel robotic endoscopic platform with suturing capabilities to overcome the technical challenges of suturing. This platform allows easy maneuvering and triangulation of the instruments, thus facilitating endoscopic suturing using robotic arms. Our studies have demonstrated that this robotic endoscopic platform with suturing capabilities is an effective and safe method for performing EFTR with endoscopic suturing.