Third Space Endoscopy: Lessons Learnt From a Decade of Submucosal Endoscopy

Peroral endoscopic tumor resection for an esophageal leiomyoma using a novel therapeutic thin endoscope

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Prevention, detection and management of adverse events of third-space endoscopy

Third space endoscopy (TSE) or sub-mucosal endoscopy using a mucosal flap valve (SEMF) enables the endoscopist to operate in the deeper layers of the gastrointestinal tract or gain access to the mediastinal/peritoneal cavity for natural orifice transoral endoscopic surgery (NOTES). TSE procedures are essentially endoscopic surgical procedures with a variable learning curve. Adverse events (AEs) during TSE are specific and follow a certain pattern across the spectrum of TSE procedures. These can be broadly categorized according to either type of AE, time of presentation relative to the procedure or according to degree of severity. Three major categories of AEs encountered during TSE include insufflation related AEs, mucosal injuries (MIs) and bleeding. Other relevant AEs include infectious complications, aspiration pneumonia, post-procedural chest/abdominal pain, atelectasis, cardiac arrhythmias, pleural effusion and pulmonary embolism. Reported incidence of AEs during TSE procedures varies according to the type and complexity of procedure. Acquaintance regarding potential risk factors, technical tips and precautions, alarm signs for early recognition, assessment of degree of severity, morphological characterization of AEs and finally, expeditious selection of appropriate management strategy are crucial and imperative for successful clinical outcomes. The current review discusses the current evidence and practical guidelines for prevention, early detection and management of TSE-related AEs.

Efficacy and safety of piecemeal submucosal tunneling endoscopic resection for giant esophageal leiomyoma

BACKGROUND AND AIMS

Giant esophageal leiomyoma usually requires a thoracotomy or thoracoscopic surgery, which is more invasive than an endoscopic treatment. The purpose of this study is to evaluate the efficacy and safety of piecemeal submucosal tunneling endoscopic resection (P-STER) for giant leiomyoma originating from the muscularis propria (MP) layer of the esophagus.

METHODS

This is a retrospective study. Patients with giant esophageal leiomyoma (transverse diameter ≥ 3 cm) who underwent P-STER were enrolled from November 2012 to May 2023. Clinical data and results were investigated.

RESULTS

A total of 16 patients were enrolled for analysis. The lesion mean transverse diameter and longitudinal diameter were 4.22 ± 1.20 cm and 6.20 ± 1.57 cm, respectively. Our mean operation time was 195.38 ± 84.99 min. The mean number of piecemeal resected was 4.31 ± 2.36. An adverse event noted was an esophageal fistula that occurred in one case (6.25%) and was treated conservatively. The mean length of hospital stay was around 11.81 ± 7.30 days. The mean total hospitalization cost was U.S. dollars (USD) $5976.50 ± 2866.39. No recurrence or metastasis was found during the follow-up period.

CONCLUSIONS

P-STER can be an effective and safe treatment for giant leiomyoma originating from the MP layer of the esophagus.

Recent advances in endoscopic management of gastric neoplasms

The development and clinical application of new diagnostic endoscopic technologies such as endoscopic ultrasonography with biopsy, magnification endoscopy, and narrow-band imaging, more recently supplemented by artificial intelligence, have enabled wider recognition and detection of various gastric neoplasms including early gastric cancer (EGC) and subepithelial tumors, such as gastrointestinal stromal tumors and neuroendocrine tumors. Over the last decade, the evolution of novel advanced therapeutic endoscopic techniques, such as endoscopic mucosal resection, endoscopic submucosal dissection, endoscopic full-thickness resection, and submucosal tunneling endoscopic resection, along with the advent of a broad array of endoscopic accessories, has provided a promising and yet less invasive strategy for treating gastric neoplasms with the advantage of a reduced need for gastric surgery. Thus, the management algorithms of various gastric tumors in a defined subset of the patient population at low risk of lymph node metastasis and amenable to endoscopic resection, may require revision considering upcoming data given the high success rate of en bloc resection by experienced endoscopists. Moreover, endoscopic surveillance protocols for precancerous gastric lesions will continue to be refined by systematic reviews and meta-analyses of further research. However, the lack of familiarity with subtle endoscopic changes associated with EGC, as well as longer procedural time, evolving resection techniques and tools, a steep learning curve of such high-risk procedures, and lack of coding are issues that do not appeal to many gastroenterologists in the field. This review summarizes recent advances in the endoscopic management of gastric neoplasms, with special emphasis on diagnostic and therapeutic methods and their future prospects.

Invasive CO 2 monitoring with arterial line compared to end tidal CO 2 during peroral endoscopic myotomy

Background and study aims  Peroral endoscopic myotomy (POEM) has become a recognized treatment for achalasia. The technique requires CO 2 insufflation. It is estimated that the partial pressure of CO 2 (PaCO 2 ) is 2 to 5 mm Hg higher than the end tidal CO 2 (etCO 2 ), and etCO 2 is used as a surrogate for PaCO 2 because PaCO 2 requires an arterial line. However, no study has compared invasive and noninvasive CO 2 monitoring during POEM. Patients and methods  Seventy-one patients who underwent POEM were included in a prospective comparative study. PaCO 2 plus etCO 2 was measured in 32 patients (invasive group) and etCO 2 only in 39 matched patients (noninvasive group). Pearson correlation coefficient (PCC) and Spearman's Rho were used to calculate the correlation between PaCO 2 and ETCO 2 . Results  PaCO 2 and ETCO 2 were strongly correlated: PCC R value: 0.8787 P  ≤ 0.00001, Spearman's Rho R value: 0.8775, P  ≤ 0.00001. Within the invasive group, the average difference between PaCO 2 and ETCO 2 was 3.39 mm Hg (median 3, standard deviation 3.5), within the 2- to 5-mm Hg range. The average procedure time (scope in to scope out) was increased 17.7 minutes ( P  = 0.044) and anesthesia duration was 46.3 minutes. Adverse events (AEs) included three hematomas and one nerve injury in the invasive group and one pneumothorax in the noninvasive group. There were no differences in AE rates between the groups (13 % vs 3 % P  = 0.24). Conclusions  Universal PaCO 2 monitoring contributes to increased procedure and anesthesia times without any decrease in AEs in patients undergoing POEM. CO 2 monitoring with an arterial line should only be performed in patients with major cardiovascular comorbidities; in all other patients, ETCO 2 is an appropriate tool.

Indications and Outcomes of Per Oral Endoscopic Myotomy from Mouth to Anus

Third space endoscopy or submucosal endoscopy using a mucosal flap valve allows secure access to the submucosal and deeper layers of the gastrointestinal tract without the risk of a full-thickness perforation. This allows the performance of submucosal tunneling and myotomy for spastic segments of the gastrointestinal tract. Per oral endoscopic myotomy (POEM) has been described for the treatment of achalasia cardia and other spastic esophageal disorders and is widely implemented. Endoscopic pyloromyotomy (G-POEM) has been performed for the treatment of refractory gastroparesis. Z-POEM for Zenker's diverticulum, D-POEM for epiphrenic diverticulum, and per-rectal endoscopic myotomy for treatment of Hirschsprung's disease are described..

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.

Modified submucosal tunneling endoscopic resection for postcricoid esophageal subepithelial tumor

Video 1Technique of submucosal tunneling and endoscopic resection for a postcricoid subepithelial esophageal tumor. After surface marking and submucosal elevation, the mucosa was incised. The subepithelial tumor was dissected from the mucosal aspect and enucleated from the muscle layer. En bloc resection was achieved with an intact capsule. The mucosal incision was closed with endoclips.

Gastroesophageal Reflux after Peroral Endoscopic Myotomy: Myth or Reality?

Peroral endoscopic myotomy (POEM) is an accepted treatment for achalasia cardia (AC), and results are comparable to those of laparoscopic Heller myotomy (LHM). In recent years, several reports have confirmed higher incidence of gastroesophageal reflux (GER) following POEM. This review evaluates the current evidence regarding post-POEM GER, critically examines the potential contributing factors responsible for GER, limitations of the current available functional testing, and precautions and preventive measures, and provides future directions for research. Factors conclusively contributing to increased post-POEM GER include injury to the sling fibers of the lower esophageal sphincter, length of gastric myotomy > 2 cm, and others. Historically, these same factors have been implicated for development of GER after surgical (laparoscopic) myotomy. Although less invasive, optimal technique of POEM may be important to control post-POEM GER. Most post-POEM GER occurs during the immediate post-POEM period, is mild, and is easily treatable using proton-pump inhibitors. GER incidence plateaus at 2 years and is comparable to that after LHM. Patients should therefore be prescribed proton-pump inhibitors for at least 2 years. Antireflux procedures (ARPs) are infrequently required in these patients as the incidence of refractory GER is low. Novel ARPs have been recently described and are currently under evaluation. Conclusive diagnosis of GER is a clinical challenge. Most patients are asymptomatic, and GER is diagnosed only on abnormal esophageal acid exposure (EAE). Studies have demonstrated that current measures to diagnose GER are inadequate, inaccurate, and cannot differentiate between true GER and abnormal EAE due to food fermentation in the distal esophagus. The Lyon Consensus criteria should be implemented for confirmation of diagnosis of GER. Finally, the review recommends an evidence-based clinical algorithm for evaluation and management of post-POEM GER and provides guidelines for future research in this field.

Single-session endoscopic fundoplication after peroral endoscopic myotomy (POEM+F) for prevention of post gastroesophageal reflux - 1-year follow-up study

BACKGROUND

Peroral endoscopic myotomy (POEM) is an established treatment for achalasia cardia; however, post-POEM gastroesophageal reflux (GER) remains a significant problem. Concomitant endoscopic fundoplication following POEM (POEM + F) was recently described to reduce post-POEM GER. This single-center study reports short-term outcomes of POEM + F.

METHODS

This was a retrospective analysis of a prospectively maintained database of patients undergoing POEM + F. Abstracted data included demographics, achalasia type, pre-POEM Eckardt score, prior therapy, follow-up. Follow-up assessment was 3-monthly for 1 year and included post-POEM Eckardt score, GerdQ score, wrap integrity and esophagitis on esophagogastroduodenoscopy, and pH studies. GER was defined according to Lyon Consensus.

RESULTS

25 patients underwent POEM + F (mean age 40.1 years [standard deviation (SD) 13.7]; 12 females). POEM + F was technically successful in 23/25 (92.0 %). Significant dysphagia improvement was seen in all 25 patients (mean pre- and post-POEM Eckardt scores 8.21 [SD 1.08] and 0.1 [SD 0.3], respectively; P = 0.001). Mean total procedure and fundoplication times were 115.6 (SD 27.2) minutes and 46.7 (SD 12.4) minutes, respectively; times reduced significantly after the initial five cases. Median follow-up was 12 months (interquartile range [IQR] 9-13). Intact wrap was seen in 19/23 (82.6 %). GER (abnormal esophageal acid exposure time [EAET]) was seen in 2/18 (11.1 %) and there was one reported GerdQ > 8. Borderline GER (asymptomatic grade A esophagitis, normal EAET) was identified in 4/22 (18.2 %). Three (12.0 %) minor delayed adverse events occurred but required no intervention. CONCLUSIONS : POEM + F was safe and reproducible. At 12 months' follow-up, incidence of post-POEM + F GER was low and acceptable.

Endoscopic diagnosis and management of gastric subepithelial lesions

PURPOSE OF REVIEW

The purpose of this manuscript is to provide an in-depth review of gastric subepithelial lesions (SELs) and describe the current approach to endoscopic diagnosis and management of these lesions.

RECENT FINDINGS

Gastric SELs are a relatively frequent finding on routine endoscopy (incidence 0.2-3%). A systematic approach to diagnosis and management is key because many SELs are of little consequence, while others carry a high risk of malignant transformation. Because esophagogastroduodenoscopy (EGD) cannot delineate depth of invasion or subepithelial appearance, endoscopic ultrasound (EUS) should be considered a first-line modality. Recent data suggest EUS-guided fine needle biopsy (FNB) may be superior to traditional fine needle aspiration (FNA) for the diagnosis of gastric SELs due to its ability to obtain histologic specimens for immunohistochemical staining. Alternative techniques for tissue sampling (combined with simultaneous resection) include submucosal resection, endoscopic submucosal dissection (ESD), submucosal tunnelling with endoscopic resection (STER) or endoscopic full-thickness resection (EFTR).

SUMMARY

This review details the endoscopic diagnosis and management of gastric SELs. Although EUS-guided sampling remains a first-line strategy (preferably with FNB), recent techniques including ESD, STER and EFTR have the potential to provide additional diagnostic and therapeutic options.