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

Third-space endoscopy: the final frontier

Over the years, our growing experience with endoscopic submucosal dissection along with technological advances has solidified our comfort and knowledge on working in the submucosa, also referred to as the "third space." Per-oral endoscopic myotomy (POEM) was the first prototype third-space endoscopy (TSE) procedure, demonstrating the feasibility and clinical utility of endoscopic esophagogastric myotomy via submucosal tunneling. The launch of POEM accelerated the evolution of TSE from a vanguard concept to an expanding field with a wide range of clinical applications. In this review, we discuss the status and future directions of multiple TSE interventions.

A Look into the Future of Endoscopic Submucosal Dissection and Third Space Endoscopy: The Role for Robotics and Other Innovation

Endoscopic resection has been widely applied especially in endoscopic submucosal dissection and third space endoscopy (TSE). Flexible endoluminal robotics allow performance of endoscopic submucosal dissection with exposure of the submucosal plane for precise dissection using two robotic arms. The introduction of TSE revolutionized the horizon of therapeutic endoscopy to the submucosal space beneath and beyond the mucosa. Advantages of TSE include avoidance of full thickness incision in gastrointestinal tract through the submucosal tunneling for performance of peroral endoscopic myotomy and submucosal tunneling endoscopic resection. In future, robotic-driven devices should be developed to enhance performance of complex endoluminal procedures and TSE.

Endoscopic adventitial dissection of a rectal GI stromal cell tumor

Video 1Demonstration of endoscopic adventitial dissection.

Efficacy and safety of gastric peroral endoscopic myotomy (G-POEM) for refractory gastroparesis: 3-year follow up results

BACKGROUND/PURPOSE

Gastroparesis is a common but easily overlooked disease. Gastric peroral endoscopic myotomy (G-POEM) is one of the third-space endoscopy techniques to treat gastroparesis. In this study, we aimed to evaluate the efficacy and safety of G-POEM for patients with refractory gastroparesis.

METHODS

Between December 2017 and 2020, we consecutively enrolled patients with gastroparesis who failed after the administration of several kinds of medication and repeated admission for nutritional support. All patients underwent gastric emptying scintigraphy and answered a questionnaire on Gastroparesis Cardinal Symptom Index (GCSI). Demographic data, endoscopic procedure, and post procedural outcome were analyzed.

RESULTS

A total of 11 (9 women and 2 men) patients with refractory gastroparesis (nine with diabetes mellitus, one systemic lupus erythematosus, and one idiopathic) were enrolled. The mean (±standard deviation (SD)) procedure time was 61.82 (±18.99) min with technical and clinical success rates of 100% and 81.82%, respectively. A statistically significant improvement was observed in the clinical severity (mean GCSI score 36.00 vs. 14.73, p < 0.0001) and gastric emptying time (mean T_1/2 341.92 vs. 65.92 min, p = 0.016) after G-POEM. Hospital stay was 7.18 (±4.49) days without mortality. Complications included 4 (36.36%) patients with self-limited postprocedural abdominal pain and 3 (27.27%) patients with intra-procedural pneumoperitoneum. During the mean follow-up period of 554.36 days, one (9.09%) patient had relapsed clinical symptoms after 6 months.

CONCLUSIONS

G-POEM is an efficient and safe pylorus-directed endoscopic therapy for refractory gastroparesis with promising results.

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.

Parapneumonic Effusion and Tension Pneumothorax after Diverticular Peroral Endoscopic Myotomy in a Woman with Large Epiphrenic Diverticulum: A Case Report and Literature Review

Esophageal diverticula (ED) represents a group of rare conditions that warrant intervention when they are symptomatic or coexisting with pulmonary disorders. Few literature reviews have described this patient entity or discussed the postoperative outcome. Therefore, I present the case of a 59-year-old woman with symptoms of dysphagia who was significantly underweight, which was conducive to the diagnosis of symptomatic ED. Because she was a poor candidate for surgery, she received a diverticular peroral endoscopic myotomy. She subsequently developed parapneumonic effusion and tension pneumothorax after the procedure. She was finally discharged on postoperative day 23. I also performed the first known comprehensive literature review of 34 published cases (including my patient) from PubMed and have addressed the demography, intervention, and prognosis for symptomatic ED after the procedure. Prompt treatment as well as prognostic measurement are crucial to successful outcomes.

Flexible endoscopic strategies for the difficult esophageal stricture

PURPOSE OF REVIEW

Benign strictures of the esophagus, caused by various causes, are frequently encountered in clinical practice. Although endoscopic dilation is still the standard and first-line therapy, complex and difficult esophageal strictures are still encountered and remain a challenge to endoscopists. The main scope of this review article is to offer a closer look at the different endoscopic modalities and approaches to complex and difficult esophageal strictures.

RECENT FINDINGS

In the past few years, endoscopic dilatation, stents including self-expandable and biodegradable types, incisional therapy, and pharmacological treatments have been utilized in the prevention and management of refractory and recurrent esophageal strictures. Meanwhile, more recent techniques such as the BougieCap, percutaneous transgastric endoscopic myotomy, through-the-scope stents, radial incision and cutting, etc. have been developed as alternative methods. A number of studies utilizing these newer methods have shown promising results in the treatment of complex and difficult esophageal strictures.

SUMMARY

Endoscopic treatment of refractory, complex and difficult esophageal strictures still remains to be a challenge for many endoscopists. While balloon or bougie dilatation still remains to be the first-line approach, other techniques have emerged as treatment alternatives and may become adjunct therapy to endoscopic dilatation.

Feasibility of using an led-probe in third-space endoscopy: a clinical study

BACKGROUND

Third-space endoscopy is a novel, safe, and effective method for treating different gastrointestinal conditions. However, several failed endoscopic procedures are attributed to incomplete myotomy. Lighting devices are used to prevent organic injuries. We aimed to investigate the feasibility of using a hand-made LED-probe (LP) in third-space procedures.

METHODS

This prospective study was conducted in a tertiary-care center in Mexico between December 2016 and January 2019. We included peroral endoscopic myotomy (POEM) and gastric peroral endoscopic myotomy(G-POEM) procedures. Pseudoachalasia, peptic ulcer, normal gastric emptying scintigraphy (GES) and prepyloric tumors were excluded. LP was used to guide or confirm procedures. Clinical and procedural characteristics were recorded and analyzed.

RESULTS

Seventy third-space procedures were included (42POEM,28G-POEM), with an average patient age of 46.7 ± 14.3 and 43.7 ± 10.1 years, respectively. For the POEM and G-POEM groups, respectively, 18/42(42.9%) and 13/28(46.7%) patients were males; median procedure times were 50 (interquartile range [IQR]: 38-71) and 60(IQR: 48-77) min, median LP placement times were 5(IQR: 4-6) and 6(IQR: 5-7) min, mild adverse events occurred in 4(9.4%) and 4(14.2%) of cases, and clinical success at 6 months occurred in 100 and 85.7% of cases. Integrated relaxation pressure (IRP) improved from 27.3 ± 10.8 to 9.5 ± 4.1 mmHg (p < 0.001); retention percentage at 4 h also improved. LP was successfully placed and adequate myotomy confirmed including 14.2 and 17.8% of POEM and G-POEM difficult patients.

CONCLUSIONS

Using an LP is promising and allows guiding during third-space procedures either for submucosal tunnel creation or myotomy confirmation, with excellent safety and efficacy in clinical practice.