Effectiveness and safety of stag beetle knife (SB knife) in management of Zenker's diverticulum: a systematic review and meta-analysis

Stag Beetle Knife (SB Knife) is increasingly being utilized for Zenker's Diverticulectomy (ZD). Our study assessed the effectiveness and safety of the SB Knife for the management of ZD. Ovid EBM reviews, Ovid Embase, Ovid Medline, ClinicalTrials.gov, Scopus, and Web of Science were searched to identify studies that utilized SB knife for ZD. Pooled proportions (PP) were calculated using the random-effects model. Heterogeneity was evaluated using I2 statistics. A total of 7 studies with 268 patients were included in the final analysis. Dysphagia and regurgitation were the most common clinical symptoms. The mean size of the ZD was 2.8 ± 0.7 cm and 28 (of 148) patients had undergone previous treatments. The PP of technical success was 98% (95% CI: 92.3-99.5; I20) with a mean procedure duration of 26.2 ± 8.3 minutes. The PP of clinical response at first follow-up and relapse after index procedure was 87.9% (95% CI: 81.6-92.3; I219) and 13.5% (95% CI: 9.6-18.6; I22), respectively. At final follow-up, the PP of clinical remission was 96.2% (95% CI: 91-98.4; I230.6) while the PP of procedure failure was 3.6% (95% CI: 1.6-8.1; I20). No severe adverse events (AEs) were noted while using the SB Knife. However, the PP of intraprocedural and postprocedural AEs was 13.2% (95% CI: 9.6-17.8; I20) and 9.3% (95% CI: 5.7-14.9; I2 < 20.9), respectively. SB Knife is highly safe and effective for Zenker's Diverticulectomy with a failure rate of only 3.6%.

Outcomes after per-oral endoscopic myotomy for Zenker's diverticula (Z-POEM) and correlation with impedance planimetry (FLIP)

INTRODUCTION

Zenker's diverticulum (ZD) is a false pulsion diverticulum of the cervical esophagus. It is typically found in older adults and manifests with dysphagia. The purpose of this study is to describe our experience with Per-oral endoscopic myotomy for Zenker's (Z-POEM) and intraoperative impedance planimetry (FLIP).

METHODS

We performed a single institution retrospective review of patients undergoing Z-POEM in a prospective database between 2014 and 2022. Upper esophageal sphincter (UES) distensibility index (DI, mm2/mmHg) was measured by FLIP before and after myotomy. The primary outcome was clinical success. Secondary outcomes included technical failure, adverse events, and quality of life as assessed by the gastroesophageal health-related quality of life (GERD-HRQL), reflux severity index (RSI), and dysphagia score. A statistical analysis of DI was done with the paired t-test (p < 0.05).

RESULTS

Fifty-four patients underwent Z-POEM, with FLIP measurements available in 30 cases. We achieved technical success and clinical success in 54/54 (100%) patients and 46/54 patients (85%), respectively. Three patients (6%) experienced contained leaks. Three patients were readmitted: one for aforementioned contained leak, one for dysphagia, and one post-operative pneumonia. Three patients with residual dysphagia underwent additional endoscopic procedures, all of whom had diverticula > 4 cm. Following myotomy, mean DI increased by 2.0 ± 1.7 mm2/mmHg (p < 0.001). In those with good clinical success, change in DI averaged + 1.6 ± 1.1 mm2/mmHg. Significant improvement was found in RSI and GERD-HRQL scores, but not dysphagia score.

CONCLUSION

Z-POEM is a safe and feasible for treatment of ZD. We saw zero cases of intraoperative abandonment. We propose that large diverticula (> 4 cm) are a risk factor for poor outcomes and may require additional endoscopic procedures. An improvement in DI is expected after myotomy, however, the ideal range is still not known.

Endoluminal treatment for Zenker's diverticulum - a population-based observational study

BACKGROUND

Zenker's diverticulum is a false diverticulum arising in the oesophago-pharyngeal junction. It may cause symptoms like dysphagia and regurgitation. In Central Norway, treatment is centralized to St. Olavs hospital, either as an endoscopic stapled oesophago-diverticulostomy procedure at the Department of Gastrointestinal Surgery or as laser diverticulostomy at the Department of Ear, Nose and Throat Surgery, depending on diverticulum size.

METHODS

Retrospective, population-based, study from 2001-2020 on patients treated for Zenker's diverticulum, at the time with a rigid endoscopic approach. Patients were identified through the in-hospital register for operations. The two treatment groups were compared on relevant pre-, intra-, and postoperative variables by review of the individual patient records.

RESULTS

78 consecutive patients, 36 at Dept. of Ear, Nose and Throat Surgery and 42 at Dept. of Gastrointestinal Surgery, were treated with a total of 104 interventions. Crude incidence for a surgery-demanding Zenker's diverticulum was 0.57 per 100 000 per year. The Dept. of Ear, Nose and Throat Surgery administered significantly less often prophylactic antibiotics than the Dept. of Gastrointestinal Surgery (p < 0.001), administered more frequently intraoperative dexamethasone (p < 0.001), and had significantly more postoperative infections (19.6% vs 3.4%, p = 0.01). No procedure-related mortality was registered. Although no standardized follow-up took place, at a median of 119 months elapsed, observed clinical recurrence was 35% for the endostapler treatment and 51% for the laser treatment procedure.

CONCLUSION

Both rigid endoscopic stapled oesophago-diverticulostomy and laser diverticulostomy are safe treatments for Zenker's diverticulum, however with a substantial risk of recurrence.

Comparing Open Versus Rigid Endoscopic and Flexible Endoscopic Techniques for the Treatment of Zenker's Diverticulum

OBJECTIVE

To describe the outcomes of patients undergoing open stapler versus transoral rigid and flexible endoscopic therapies for symptomatic Zenker's diverticulum.

STUDY DESIGN

Single institution retrospective review.

SETTING

Tertiary care academic hospital.

METHODS

We retrospectively evaluated the outcomes of 424 consecutive patients who underwent Zenker's diverticulotomy via an open stapler, rigid endoscopic CO2 laser, rigid endoscopic stapler, rigid endoscopic harmonic scalpel, or flexible endoscopic technique from January 2006 to December 2020.

RESULTS

A total of 424 patients (173 females, mean age 73.1 ± 11.2 years) from a single institution were included. A total of 142 patients (33%) underwent endoscopic laser treatment, 33 (8%) underwent endoscopic harmonic scalpel, 92 (22%) underwent endoscopic stapler, 70 (17%) underwent flexible endoscopic, and 87 (20%) underwent open stapler. All open and rigid endoscopic procedures and most of the flexible endoscopic procedures (65%) were performed under general anesthesia. The flexible endoscopic group had a higher percentage of procedure-related perforation, defined as subcutaneous emphysema or contrast leak on imaging (14.3%). The recurrence rates were higher in the harmonic stapler, flexible endoscopic, and endoscopic stapler groups at 18.2%, 17.1%, and 17.4%, respectively, and lower in the open group (1.1%). Length of hospital stay and return to oral intake were similar among groups.

CONCLUSION

The flexible endoscopic technique was associated with the highest rate of procedure-related perforation, while the endoscopic stapler had the lowest number of procedural complications. Recurrence rates were higher among the harmonic stapler, flexible endoscopic, and endoscopic stapler groups and lower in the endoscopic laser and open groups. Prospective comparative studies with long-term follow-up are needed.

Concurrent Killian-Jamieson and Zenker's Diverticula

Pharyngoesophageal diverticula are rare causes of dysphagia. Zenker's diverticulum is the most common type, followed by Killian-Jamieson diverticulum. A 44-year-old male presented to our clinic with a longstanding history of dysphagia and globus sensation. Bilateral pharyngoesophageal diverticula were confirmed by imaging CT and esophagogastroscopy. He underwent transcervical resection, and a right Killian-Jamieson diverticulum was observed during surgery. The left diverticulum was found to originate above the cricopharyngeus muscle and was labeled as Zenker's diverticulum. Bilateral pharyngoesophageal diverticula are rare, and physicians should be aware of the variable clinical presentations and management options for pharyngoesophageal diverticula.

Flexible Endoscopy Versus Rigid Endoscopy or Surgery for the Management of Zenker's Diverticulum: A Systematic Review and Meta-Analysis

Zenker's diverticulum treatment options range from endoscopic rigid or flexible procedures to surgery. There are limited studies available comparing these techniques. Frequently, the choice of treatment depends on the physician's preference or experience, as well as the institution's resources and capacity. Therefore, this study aims to define the best approach based on the highest efficacy and the lowest severe adverse events. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive search was performed. Only comparative studies were included, analyzing flexible endoscopy versus rigid endoscopy or surgery. The outcomes analyzed were clinical and technical success, severe adverse events, length of stay, and duration of the procedure. Analysis was performed using Review Manager 5.4.1 (RevMan 5.4, The Cochrane Collaboration, The Nordic Cochrane Centre, Copenhagen, Denmark). Eight retrospective cohort studies met the inclusion criteria. A total of 1281 patients were identified, 492 underwent flexible endoscopy, 453 underwent rigid endoscopy, and 336 underwent surgery. There was no difference in clinical success [risk difference (RD), 0.07 (95% CI -0.05 to 0.19%); P = 0.26], technical success [RD, 0.07 (95% CI -0.03 to 0.16); P = 0.18], severe adverse events [RD, -0.03 (95% CI -0.13 to 0.07; P = 0.052), perforation [RD, 0.07 (95% CI -0.04 to 0.19); P = 0.22] or procedure time [mean difference (MD), - 10.03 (95% CI -26.93 to 6.88); P = 0.24). There was lower length of stay with flexible endoscopy compared to the other approaches [MD, -1.98 (95% CI -3.56 to -0.40); P = 0.001]. Based on the current evidence, the three main techniques are effective for the treatment of Zenker's diverticulum. Although there was no significant difference in the safety of each technique in this meta-analysis, this result should be interpreted cautiously due to the limited data and the risk of vies between the techniques, considering that the results tend to favor flexible endoscopy, mainly explained by the newer and safer devices. Length of stay is lower with flexible endoscopy versus the other techniques, which can be beneficial considering the geriatric populations where Zenker's diverticulum mainly occurs.

Postoperative Complications and Reoperative Surgery in the Treatment of Patients With Zenker Diverticulum

Importance

The association of the surgical approach, surgical specialty, and other factors with the outcomes of surgical treatment of Zenker diverticulum (ZD) have been debated in the literature.

Objectives

To explore the outcomes of 3 different surgical methods used in the management of ZD and determine the associations between patient characteristics, such as preoperative comorbidities and treatment outcomes.

Design, Setting, and Participants

This retrospective, population-based cohort study examined patient records of patients who underwent surgical treatment for ZD from the Care Register for Healthcare database in Finland between January 1996 and December 2015. Data review and analysis were completed in 2021.

Exposure

Surgical treatment for ZD.

Main Outcome and Measures

Complications of surgical procedures used in the management of ZD.

Results

In this study, 1044 patients (median [IQR] age, 70.0 [22.0-98.0] years; 416 female individuals [39.8%]) surgically treated for ZD were identified. Most patients (606 [58.0%]) had no preoperative comorbidities. A total of 67 (6.4%) complications were recorded, with a mortality rate of 0.9%. The likelihood of complications was associated with patient age (t [1042] = 2.28; Cohen d, 0.29; 95%, CI 0.04, 0.54), surgical approach (Cramer V = 0.14 [95% CI 0.07-0.21]), and surgical specialty (Cramer V, 0.16; 95% CI, 0.06-0.28). The median (IQR) length of stay in association with the primary surgical intervention was 3.0 (0-85.0) days. Length of stay was associated with patient age (Cramer V, 0.14; 95% CI, 0.06-0.25), especially in patients older than 90 years, surgical approach (F [2, 466.2] = 26.9; ηp2 = 0.08; 95% CI, 0.05-0.11), and surgical specialty (F [4, 22.1] = 11.0; ηp2 = 0.07; 95% CI, 0.04-0.10). Reoperation was associated with the initial surgical approach (Cramer V, 0.18; 95% CI, 0.12-0.23) and surgical specialty (Cramer V, 0.14; 95% CI, 0.09-0.21).

Conclusions and Relevance

The results of this cohort study suggest that the outcomes of surgical management depended on the surgical approach, surgical specialty, and patient age. Overall, surgical treatment may be considered safe and may be considered for all patients with symptomatic ZD.

A cooperative approach for treatment of Zenker's diverticulum

BACKGROUND

Symptomatic Zenker's diverticulum management has evolved from an open intervention to an endoscopic management. At our center, both an otolaryngologist and a gastroenterologist are present in the operating room when treating these lesions. An intra-procedural consensus is reached to undergo either rigid endoscopy or flexible endoscopic diverticulotomy with ENT guidance. We evaluated the real-world efficacy with a cooperative gastroenterology-otolaryngology approach.

METHODS

Single-center retrospective study of patients who underwent a cooperative endoscopic diverticulotomy by a gastroenterologist and otolaryngologist at Cleveland Clinic Florida between 2012 and 2019. Demographic and clinical data, intra-procedural findings/complications, post-procedural symptoms, recurrence rate, and reintervention variables were extracted. Patients included in the study were > 17 years old, with symptomatic confirmed typical single Zenker's diverticulum.

RESULTS

63 subjects were identified. Patients were predominantly males (63.5%) and white (84.1%), with mean age 73.5 years (53-95). Most subjects presented dysphagia (98.4%), mostly to solids (79.4%). Other demographic and clinical data are described in Table 1. The diverticula had a mean size of 36.3 mm. In 30.1% of the cases food debris was found during the procedure. The mean procedure length was 38.4 minutes. All cases were performed as outpatient. Technical success was achieved in all cases. Patients were followed for a mean of 3.24 months post-procedure. Clinical success was achieved in 92% subjects. One intra-procedural perforation was treated with endoclip. Table 1 Pre-procedural demographic and clinical variables in patients undergoing Zenker's diverticulum cooperative approach Variable Value (n = 63) Sex, n (%)  Male  Female 40 (63.5) 23 (36.5) Ethnicity/Race, n (%)  Non-Hispanic White  Hispanic  Black 53 (84.1) 7 (11.1) 3 (4.8) Smoking status, n (%)  Never  Former  Active 29 (46.0) 26 (41.3) 8 (10.7) Previous intervention for Zenker's diverticulum, n (%) 12 (19.1) Dysphagia, n (%)  Only to solids  Only to liquids  Both solids and liquids 50 (79.4) 0 (0) 12 (19.0) Regurgitation of food, n (%)  Chronic cough, n (%) 13 (20.6)  Halitosis, n (%) 9 (14.3) CONCLUSION: A cooperative endoscopic approach by gastroenterology and otolaryngology for symptomatic Zenker's diverticulum management offered excellent technical and clinical success. This approach proved to be safe and effective.

Results of laser surgery in the treatment of Zenker's diverticulum

INTRODUCTION

Zenker's diverticulum is an uncommon pathology of the upper oesophageal sphincter whose most frequent symptoms are the association of dysphagia and regurgitation. It is more frequent in advanced ages, and its treatment of choice is surgery in symptomatic cases.

METHOD

A retrospective descriptive study was performed of 27 patients operated in the Otorhinolaryngology service of the Hospital Universitario de Cabueñes between 2007 and 2019 using laser endoscopic surgery.

RESULTS

27 patients were operated, 70.4% male and 29.6% female, with a mean age of 67 years (range between 30 and 91). The most frequent symptom at diagnosis was dysphagia. No intraoperative complications were observed. One patient (3.7%) presented post-surgical fever, and another patient (3.7%) had a serious complication due to oesophageal perforation secondary to postsurgical emesis. The median hospital stay was 5 days, and the median oral intake was 4 days. Recurrence was observed in 6 patients (22.2%), 4 (14.8%) requiring a second intervention, which was performed using the same technique.

DISCUSSION AND CONCLUSIONS

The surgical treatment of Zenker's diverticulum has advanced in recent decades, with endoscopic treatment currently being the choice. Among the surgical options, endoscopic CO2 laser surgery is an effective and safe alternative, although possible complications must be considered. It is also an effective alternative for the treatment of recurrences.

Pharyngeal Pouch Surgery in Octo- and Nonagenarians is Safe and Effective: A Multicentre Comparative Cohort Study

BACKGROUND

Surgery is the only effective treatment strategy for a symptomatic pharyngeal pouch. However, octo- and nonagenarians are often denied referral to a surgeon because of perceived increased risks. Here, we compare the outcomes of pharyngeal pouch surgery in octo- and nonagenarians with patients under 80 years-of-age and determine the factors which predict post-operative complications and improvement in swallowing.

METHODS

Analysis of a prospectively maintained database of patients who underwent pharyngeal pouch surgery across seven hospitals over 15 years.

RESULTS

In total, 113 patients (≥80 years-of-age: 27, <80 years-of-age: 86) underwent endoscopic or open pharyngeal pouch surgery. Despite more comorbidities and a longer hospital stay (median: one extra day), patients ≥80 years-of-age had comparable operative time, complication profile, intensive care admission, emergency reoperation, and revisional pouch surgery as their younger counterparts. Furthermore, the severity of complications was not significantly different between the two age cohorts. No surgical mortality was recorded. Multivariate analysis demonstrated that diverticulectomy combined with cricopharyngeal myotomy independently predicted higher rates of complications (OR: 4.53, 95% CI: 1.43-14.33, p = 0.010), but also greater symptomatic improvement (OR: 4.36, 95% CI: 1.50-12.67, p = 0.007). Importantly, a greater proportion of octo- and nonagenarians experienced improved swallowing than patients <80 years-of-age (96.3% vs. 74.4%, p = 0.013). Moreover, advanced age was not predictive of post-operative complications on multivariate analysis.

CONCLUSIONS

Pharyngeal pouch surgery in octo- and nonagenarians is safe and effective. Surgical correction in this age group alleviates symptoms and improves quality-of-life for most patients. These patients should not be denied surgery on the basis of advanced age alone.

Secondary tracheoesophageal puncture with the blind technique: 10 years' experience

PROPOSE

The aim of the present article is to propose an alternative technique to the traditional secondary tracheoesophageal puncture (TEP) for voice rehabilitation after total laryngectomy, describing the procedure step-by-step, analyzing the complications and long-term results.

METHODS

A retrospective study was conducted on patients who underwent secondary TEP with the blind technique using a rigid hysterometer. The main steps in this technique are described and illustrated. Patient demographics and surgical outcomes were assessed.

RESULTS

Thirty-two patients were enrolled in this study. In all but one case, risk factors that could hinder rigid esophagoscopy were identified (37.5% neopharyngeal/esophageal post-surgical issues, 81.3% prior radiotherapy, 21.9% cervical arthrosis, and 12.5% prior coloplasty or gastric transposition). No intra- or postoperative surgical complications were noted.

CONCLUSION

The blind technique offers an alternative method to perform a secondary TEP safely and efficiently in patients with unfavorable anatomical or clinical conditions, lowering the risk of procedure-related complications.

Results of laser surgery in the treatment of Zenker's diverticulum

INTRODUCTION

Zenker's diverticulum is an uncommon pathology of the upper oesophageal sphincter whose most frequent symptoms are the association of dysphagia and regurgitation. It is more frequent in advanced ages, and its treatment of choice is surgery in symptomatic cases.

METHOD

A retrospective descriptive study was performed of 27 patients operated in the Otorhinolaryngology service of the Hospital Universitario de Cabueñes between 2007 and 2019 using laser endoscopic surgery.

RESULTS

27 patients were operated, 70.4% male and 29.6% female, with a mean age of 67 years (range between 30 and 91). The most frequent symptom at diagnosis was dysphagia. No intraoperative complications were observed. One patient (3.7%) presented post-surgical fever, and another patient (3.7%) had a serious complication due to oesophageal perforation secondary to postsurgical emesis. The median hospital stay was 5 days, and the median oral intake was 4 days. Recurrence was observed in 6 patients (22.2%), 4 (14.8%) requiring a second intervention, which was performed using the same technique.

DISCUSSION AND CONCLUSIONS

The surgical treatment of Zenker's diverticulum has advanced in recent decades, with endoscopic treatment currently being the choice. Among the surgical options, endoscopic CO2 laser surgery is an effective and safe alternative, although possible complications must be considered. It is also an effective alternative for the treatment of recurrences.

Flexible endoscopic treatment for Zenker's diverticulum: from the lumen to the third space

Zenker’s diverticulum (ZD) is a rare outpouching of the esophageal mucosa herniating posteriorly through Killian’s triangle. Treatments of ZD aim to dissect the cricopharyngeal muscle to remove the underlying dysfunctional condition. In the last decade, a septotomy performed utilizing a flexible endoscope has been reported as a safe and effective alternative to both open surgery and rigid endoscopic diverticulotomy. More recently, Li et al described a novel endoscopic technique to treat ZD, named “submucosal tunneling endoscopic septum division”, inspired by the peroral endoscopic myotomy (POEM) procedure developed for achalasia. Subsequently, the term Z-POEM was introduced and has become the most frequently used acronym to define the tunneling technique for ZD. This article describes the flexible therapeutic endoscopic strategies for treating ZD, including the novel third space approach, which seems to show promising potential in terms of clinical efficacy and safety.

Per Oral Zenker Diverticulotomy

Zenker diverticulum (ZD) is a rare but treatable surgical disease affecting the elderly. This article reviews current available evidence and management of ZD, which includes open surgical, rigid endoscopic, and flexible endoscopic diverticulotomy with common goal of complete division of cricopharyngeus muscle. Careful patient selection and operative intervention tailored to patient characteristics is important when evaluating patients for operative intervention for ZD. Described in detail is a novel flexible endoscopic approach using submucosal tunneling technique to perform cricopharyngeal myotomy, also called per oral endoscopic myotomy, which is demonstrated to be safe and effective in the management of ZD with low morbidity.

Endoscopic mucosal incision and muscle interruption (MIMI) for the treatment of Zenker's diverticulum

BACKGROUND

In peroral endoscopic myotomy for Zenker's diverticulum (Z-POEM), the cricopharyngeus muscle is divided within a submucosal tunnel started in the hypopharynx. We aimed to evaluate the safety and preliminary outcomes in patients who underwent a modified version of the Z-POEM where the tunnel is made directly overlying the cricopharyngeus, the mucosal incision and muscular interruption (MIMI) approach, and to compare these with patients who underwent a non-tunneled flexible endoscopic approach.

METHODS

All patients with ZD who were treated by flexible endoscopy at our institution between January 2015 and February 2020 were identified by a retrospective chart review. Dysphagia symptoms were assessed using a validated scoring system.

RESULTS

Nineteen patients with ZD underwent MIMI (mean age 76.1 years, 68.1% male) and seven patients underwent non-tunneled flexible endoscopic approach (mean age 64.4 years, 85.7% male) during the study period. Mean ZD size was 2.8 cm in the MIMI group and 1.9 cm in the non-tunneled group (p = 0.03). Clinical success was achieved in 17/19(89.5%) MIMI patients and 7/7(100%) of non-tunneled flexible endoscopic patients (p = 0.101). Dysphagia scores improved in both groups, although this difference was only significant in the MIMI group (p ≤ 0.001). Recurrence occurred in 2/17(11.7%) MIMI patients and 3/7(42.9%) non-tunneled flexible endoscopic patients (p = 0.096). There were 4 complications, including one pharyngeal perforation requiring open surgical repair in a patient with a small ZD with an associated cricopharyngeal bar in the MIMI group. Median length of follow-up was 290 [142; 465] days in the MIMI group and 1056 [258; 1206] days in the non-tunneled group (p = 0.094).

CONCLUSIONS

MIMI is a technically feasible and effective treatment for ZD. Care should be taken in patients with a cricopharyngeal bar and small ZD, as this may increase the risk of perforation. Larger studies with long-term follow-up are needed to determine if MIMI reduces the risk of symptom recurrence when compared to non-tunneled flexible endoscopic approaches.

Flexible Endoscopic Zenker's Diverticulotomy with an Articulating Bipolar Energy Sealer

The surgical management of Zenker's diverticula is performed through open or endoscopic approaches. The purpose of this report is to review our early experience with flexible endoscopic diverticulotomy with an articulating bipolar energy sealer for cricopharyngeal and diverticular wall division in a series of 5 patients where transoral rigid access was not possible. In addition to technical details, safety and efficacy data are included. The average diverticulum size was 2.5 cm. All patients reported symptom resolution, and there were no surgical complications. Liquid diet was initiated on postoperative day 1 for all patients and solids on day 11.8 ± 14.4 (mean ± SD) per protocol. Results demonstrate that treatment of Zenker's diverticula can safely and successfully be performed with flexible endoscopic visualization and utilization of an articulating bipolar energy sealer to perform diverticulotomy in a population of patients where transoral diverticulotomy would not otherwise be feasible due to anatomic constraints. Early results support obtaining further experience to study this technology as an alternative to open surgery, especially when visualization and access are suboptimal with rigid endoscopy.