Safety and Feasibility of Per-Oral Pyloromyotomy as Augmentative Therapy after Prior Gastric Electrical Stimulation for Gastroparesis

Gastroparesis: An Evidence-Based Review for the Bariatric and Foregut Surgeon

Gastroparesis is a gastric motility disorder characterized by delayed gastric emptying. It is a rare disease and difficult to treat effectively; management is a dilemma for gastroenterologists and surgeons alike. We conducted a systematic review of the literature to evaluate current diagnostic tools as well as treatment options. We describe key elements in the pathophysiology of the disease, in addition to current evidence on treatment alternatives, including nutritional considerations, medical and surgical options, and related outcomes.

Targeting the pylorus in gastroparesis: From physiology to endoscopic pyloromyotomy

BACKGROUND

The pylorus plays a key role in the control of gastric content outflow. Impairment of pyloric physiology has been observed in gastroparesis, particularly when associated with diabetes mellitus or opioid intake or after antireflux surgery. New tools have been developed to identify pyloric dysfunction in routine care, including functional luminal impedance planimetry (FLIP). As such, a new therapeutic strategy targeting the pylorus, namely endoscopic pyloromyotomy (G-POEM), has received increasing attention and emerged as a promising treatment for gastroparesis.

PURPOSE

The present review details the involvement of the pyloric pathophysiology in gastroparesis, as well as clinical results of G-POEM according to the current literature.

ACG Clinical Guideline: Gastroparesis

Gastroparesis is characterized by symptoms suggesting retention of food in the stomach with objective evidence of delayed gastric emptying in the absence of mechanical obstruction in the gastric outflow. This condition is increasingly encountered in clinical practice. These guidelines summarize perspectives on the risk factors, diagnosis, and management of gastroparesis in adults (including dietary, pharmacological, device, and interventions directed at the pylorus), and they represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence for these guidelines was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation process. When the evidence was not appropriate for Grading of Recommendations, Assessment, Development, and Evaluation, we used expert consensus to develop key concept statements. These guidelines should be considered as preferred but are not the only approaches to these conditions.

Gastric Electrical Stimulation: Role and Clinical Impact on Chronic Nausea and Vomiting

Gastric electrical stimulation (GES) is currently used as an alternative treatment for medically refractory gastroparesis. GES has been initially developed to accelerate gastric motility, in order to relieve the symptoms of the patients. Subsequent studies, unfortunately, failed to demonstrate the acceleration of gastric emptying using high-frequency stimulation – low energy stimulation although the technique has shown a clinical impact with a reduction of nausea and vomiting for patients with gastroparesis. The present review details the clinical efficacy of GES in gastroparesis as well as its putative mechanisms of action.

POEM, GPOEM, and ZPOEM

Our tripartite narrative review discusses Peroral Endoscopic Myotomy (POEM), gastric POEM (GPOEM) and POEM for Zenker's diverticula (ZPOEM). POEM is the prototypical procedure that launched the novel "3rd space endoscopy" field of advanced endoscopy. It revolutionized achalasia therapy by offering a much less invasive version of the prior gold standard, the laparoscopic Heller myotomy (HM). We review in detail indications, outcomes, technique variations and comparative data between POEM and HM particularly with regard to the hotly debated issue of GERD. We then proceed to discuss two less illustrious but nevertheless important offshoots of the iconic POEM procedure: GPOEM for gastroparesis and ZPOEM for the treatment of hypopharyngeal diverticula. For GPOEM, we discuss the rationale of pylorus-directed therapies, briefly touch on GPOEM technique variations and then focus on the importance of proper patient selection and emerging data in this area. On the third and final part of our review, we discuss ZPOEM and expound on technique variations including our "ultra-short tunnel technique". Our review emphasizes that, despite the superiority of endoscopy over surgery for the treatment of hypopharyngeal diverticula, there is no clear evidence yet of the superiority of the newfangled ZPOEM technique compared to the conventional endoscopic myotomy technique practiced for over two decades prior to the advent of ZPOEM.

Gastroparesis

Gastroparesis is characterized by symptoms suggestive of, and objective evidence of, delayed gastric emptying in the absence of mechanical obstruction. This review addresses the normal emptying of solids and liquids from the stomach and details the myogenic and neuromuscular control mechanisms, including the specialized function of the pyloric sphincter, that result in normal emptying, based predominantly on animal research. A clear understanding of fundamental mechanisms is necessary to comprehend derangements leading to gastroparesis, and additional research on human gastric muscles is needed. The section on pathophysiology of gastroparesis considers neuromuscular diseases that affect nonsphincteric gastric muscle, disorders of the extrinsic neural control, and pyloric dysfunction that lead to gastroparesis. The potential cellular basis for gastroparesis is attributed to the effects of oxidative stress and inflammation, with increased pro-inflammatory and decreased resident macrophages, as observed in full-thickness biopsies from patients with gastroparesis. Predominant diagnostic tests involving measurements of gastric emptying, the use of a functional luminal imaging probe, and high-resolution antral duodenal manometry in characterizing the abnormal motor functions at the gastroduodenal junction are discussed. Management is based on supporting nutrition; dietary interventions, including the physical reduction in particle size of solid foods; pharmacological agents, including prokinetics and anti-emetics; and interventions such as gastric electrical stimulation and pyloromyotomy. These are discussed briefly, and comment is added on the potential for individualized treatments in the future, based on optimal gastric emptying measurement and objective documentation of the underlying pathophysiology causing the gastroparesis.

Endoscopic Equipment-From Simple to Advanced

Flexible endoscopic procedures, such as esophagogastroduodenoscopies and colonoscopies, allow for diagnosis and treatment of numerous gastrointestinal disorders. Advanced endoscopic procedures, such as endoscopic ultrasounds, endoscopic retrograde cholangiopancreatography, and balloon enteroscopies, offer therapeutic options that are minimally invasive and effective. As technology advances, the equipment and tools in an endoscopist's armamentarium continue to grow. This article highlights key endoscopic equipment and supplies, from simple to advanced.

Feasibility, safety, and long-term efficacy of gastric peroral endoscopic myotomy (G-POEM) for postsurgical gastroparesis: a single-center and retrospective study of a prospective database

BACKGROUND

Postsurgical gastroparesis is recognized as a gastrointestinal dysfunction syndrome following foregut surgery. Gastric peroral endoscopic myotomy (G-POEM) is suggested as a minimally invasive therapy for gastroparesis. But the long-term efficacy and safety of G-POEM in treating postsurgical gastroparesis are rarely explored.

METHODS

The primary outcomes included the symptomatic improvement based on gastroparesis cardinal symptoms index (GCSI) and the improvement of gastric emptying. The secondary outcomes included the improvement of gastroesophageal reflux symptoms and complications of G-POEM.

RESULTS

The severity of postsurgical gastroparesis was not associated with the onset time and the course of the disease. G-POEM significantly reduced GCSI throughout the follow-up period (p < 0.0001). For different anastomotic site, a significant improvement of GCSI was found at 6 month post-G-POEM (F_4,165 = 74.18, p < 0.0001). Subscale analysis of GCSI showed that nausea/vomiting, post-prandial fullness/early satiety, and bloating were improved significantly at 6-month post-G-POEM (p < 0.0001, respectively). Half-emptying and whole-emptying time were significantly shortened in patients with different anastomotic site post-G-POEM (half-emptying time: F_3,174 = 65.44, p < 0.0001; whole-emptying time: F_3,174 = 54.85, p < 0.0001). The emptying of ioversol was obviously accelerated after G-POEM. GCSI wasn't related to pyloric length, pyloric diameter, and thickness of pyloric wall. GERDQ was also used to evaluate the clinical efficacy of G-POEM. For each time points, GERDQ didn't differ significantly in patients with different anastomotic site (F_4,104 = 0.8075, p = 0.5231). For patients with different anastomotic site, GERDQ was improved significantly at different time points (F_4,104 = 59.11, p < 0.0001). The higher the esophageal anastomotic site was, the faster G-POEM improved the symptoms of gastroesophageal reflux. No one required re-hospitalization for any complication.

CONCLUSION

G-POEM is a minimally invasive therapy with long-term effectiveness and safety in treating postsurgical gastroparesis.