Applying the Functional Luminal Imaging Probe to Esophageal Disorders

Functional Lumen Imaging Probe Panometry

Functional lumen imaging probe (FLIP) Panometry has emerged as a valuable tool for evaluating esophageal function by measuring mechanical properties and motor patterns of the esophagus during volumetric distension. Unlike high-resolution manometry, FLIP can be performed during endoscopy, providing real-time assessment of esophageal distensibility, esophagogastric junction opening, and esophageal contractile response patterns. This review summarizes the technical aspects, standardized protocol, and interpretation of FLIP studies. Clinical applications are discussed across various esophageal disorders, including achalasia, esophageal motility disorders, and eosinophilic esophagitis, as well as its role in guiding surgical interventions and assessing treatment outcomes.

Post-bariatric Surgery Changes in Secondary Esophageal Motility and Distensibility Parameters

INTRODUCTION

Despite the increasing number of bariatric procedures over the recent years, the physiological changes in secondary esophageal motility and distensibility parameters after surgery remain unknown.

METHODS

This is a retrospective, single-center cohort study comparing esophageal planimetry and gastroesophageal junction (GEJ) distensibility in post-bariatric surgery patients (Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), and conversion/revisional patients (DH)) and native-anatomy patients with obesity (NAC). Distensibility refers to the area achieved with a certain amount of pressure, and secondary peristalsis represents the esophageal response to an intended obstruction. Patients with pre-surgical dysmotility symptoms were excluded from the study.

RESULTS

From November 2018 to January 2023, 167 patients were evaluated and eligible for this study (RYGB = 87, SG = 33, NAC = 22, DH = 25). In NAC cohort, 17/22 (77%) patients presented normal motility patterns compared to 35/87 (40%) RYGB, 12/33 (36%) SG, and 5/25 (20%) DH (p < 0.05 for all comparisons). The most common abnormal motility pattern for all three bariatric cohorts was absent contractions. DH patients generally had the highest mean maximum distensibility index averages, followed by SG, RYGB, and NAC.

CONCLUSION

Bariatric surgery affects esophageal and GEJ physiology, and it is associated with higher rates of secondary dysmotility. DH patients have even higher rates of dysmotility. Further studies assessing clinical data and their correlation with manometric and pH-metric findings are needed.

Role of short interval FLIP panometry in predicting long-term outcomes after per-oral endoscopic myotomy

BACKGROUND

The Eckardt score (ES) is used to assess symptom response to Per-Oral Endoscopic Myotomy (POEM), but reliable methods to assess physiologic success are needed. Functional lumen imaging probe (FLIP) panometry has a potential role in post-POEM follow-up to predict long-term outcomes. The aim of this study was to assess the correlation between clinical success and FLIP parameters following POEM to determine if short interval FLIP could predict long-term outcomes.

METHODS

This was a prospective study of adult patients who underwent POEM with short interval follow-up FLIP between 11/2017 and 3/2020. Clinical success was defined as post-procedure ES ≤ 3. Physiologic success was based on an esophago-gastric junction distensibility index (EGJ-DI) > 2.8 mm2/mmHg on FLIP.

RESULTS

47 patients (55% female, mean age 55 years) were included in the study. Clinical success after POEM was seen in 45 (96%) patients (mean ES 6.5 ± 2.2 pre and 0.83 ± 1.0 post-POEM, p < 0.001). Physiologic success was noted in 43 (91.5%) patients (mean EGJ-DI 6.1 mm2/mmHg ± 2.5). Among 4 patients not meeting criteria for physiologic success, EGJ-DI was 2.5-2.6. There was no correlation between post-POEM EGJ-DI and ES in the short term or long term. Significant reflux esophagitis was seen in 6 (12.8%) patients with no difference in mean EGJ-DI with vs without esophagitis (5.9 vs 6.1, p = 0.44).

CONCLUSION

Post-POEM endoscopy with FLIP is useful to both assess EGJ physiology and to examine for reflux esophagitis. Short interval FLIP has limited utility to predict long-term patient outcomes or risk of acid reflux.

Development and Evaluation of a Flexible PVDF-Based Balloon Sensor for Detecting Mechanical Forces at Key Esophageal Nodes in Esophageal Motility Disorders

Prevailing methods for esophageal motility assessments, such as perfusion manometry and probe-based function imaging, frequently overlook the intricate stress fields acting on the liquid-filled balloons at the forefront of the probing device within the esophageal lumen. To bridge this knowledge gap, we innovatively devised an infusible flexible balloon catheter, equipped with a quartet of PVDF piezoelectric sensors. This design, working in concert with a bespoke local key-node analytical algorithm and a sensor array state analysis model, seeks to shed new light on the dynamic mechanical characteristics at pivotal esophageal locales. To further this endeavor, we pioneered a singular closed balloon system and a complementary signal acquisition and processing system that employs a homogeneously distributed PVDF piezoelectric sensor array for the real-time monitoring of dynamic mechanical nuances in the esophageal segment. An advanced analytical model was established to scrutinize the coupled physical fields under varying degrees of balloon inflation, thereby facilitating a thorough dynamic stress examination of local esophageal nodes. Our rigorous execution of static, dynamic, and simulated swallowing experiments robustly substantiated the viability of our design, the logical coherence of our esophageal key-point stress analytical algorithm, and the potential clinical utility of a flexible esophageal key-node stress detection balloon probe outfitted with a PVDF array. This study offers a fresh lens through which esophageal motility testing can be viewed and improved upon.

Eosinophilic Esophagitis-What Do We Know So Far?

Eosinophilic esophagitis is a Th-2 antigen-mediated disease in which there is an influx of eosinophils to all layers of the esophagus, triggering an inflammatory response. Chronic inflammatory process causes esophageal remodeling, leading to difficulties in swallowing. Food impaction, heartburn, and chest pain are other characteristic (but not pathognomonic) symptoms in adults. Although the disease has only been described since in the early 1970s, its incidence and prevalence are rapidly growing, especially in Western countries. According to the diagnostic guidelines, there should be at least 15 eosinophils visible per high-power field in biopsies obtained from different sites in the esophagus upon endoscopy with relevant esophageal symptoms. Other diseases that can cause esophageal eosinophilia should be ruled out. Eosinophilic esophagitis treatment may be challenging; however, new methods of management have recently emerged. The currently used proton pump inhibitors, topical corticosteroids, and elimination diet are combined with biological treatment. New methods for disease diagnostics and clinical course assessment are also available. This review presents current knowledge about the disease, supported by the latest research data.

Role of functional luminal imaging probe in the management of postmyotomy clinical failure

BACKGROUND AND AIMS

A small percentage of patients with esophageal dysmotility disorders (EDDs) fail to improve or relapse after management by laparoscopic Heller myotomy (LHM) and peroral endoscopic myotomy (POEM). In this study, we aimed to describe the role of functional luminal imaging probe (FLIP) in identifying patients who might benefit from lower esophageal sphincter (LES)-directed retreatment.

METHODS

This was a retrospective study at 6 tertiary care centers (United States, 4; Europe, 1; Asia, 1) between January 2015 and April 2021 involving patients with prior failed myotomy. The primary outcome was the impact of the use of FLIP on the management of patients with prior failed myotomy.

RESULTS

One hundred twenty-three patients (62 women [50%]; mean age, 53 ± 21.1 years) who underwent LHM (n = 53, 43%) or POEM (n = 70, 57%) for the management of achalasia (n = 98) or other EDDs (n = 25) had clinical failure at a median time of 10.8 months (interquartile range, .8-17.3) postprocedure. Twenty-nine patients had apposing "abnormal" diagnoses in terms of integrated relaxation pressure (IRP) >15 mm Hg on HRM and distensibility index (DI) <2.8 mm²/mm Hg on FLIP, with ultimate change in management noted in 15 patients (10 directed toward conservative management, 5 directed toward LES-directed retreatment). The impact of FLIP on both diagnosis and management was noted in 15 of 29 patients (52%). In the subgroup analysis of 44 patients who underwent LES-directed retreatment, clinical success was highest among patients with both abnormal IRP and DI (21/25 [84%]) versus patients with only abnormal IRP (8/14 [57%]) or only abnormal DI (3/5 [60%], P = .04), with DI at 40-mL distension volume on FLIP identified as an independent predictor of clinical success (odd ratio, 1.51; 95% confidence interval, 1.02-2.1; P = .03).

CONCLUSIONS

The finding of this study further suggests the important role of using FLIP in addition to HRM in evaluating patients with clinical failure postmyotomy.

Pathophysiology of Pediatric Gastroesophageal Reflux Disease: Similarities and Differences With Adults

Gastroesophageal reflux (GOR) is defined as "the passage of gastric contents into the esophagus with or without regurgitation and vomiting" and gastroesophageal reflux disease (GORD) is defined "when GOR leads to troublesome symptoms affecting the daily functioning and/or complications." This definition was first developed in 2006 by the Montreal consensus group (1) and later on adopted by pediatric gastroenterology societies such as ESPGHAN and NASPGHAN in 2009 (2). The definition of gastroesophageal reflux reveals little about its pathophysiology and is focused on symptomatology. In this way, it acts as an umbrella term for the multifactorial causes of the disease and the various phenotypes encountered; from functional heartburn to hypersensitive esophagus and nonerosive reflux disease, to erosive esophagitis and Barrett's esophagus. This article is devoted to the pathophysiology of pediatric GORD in comparison to adult GORD and is divided in 2 parts. In the first part, we will systematically describe the different mechanisms for the generation and clearance of reflux events, while on the second part we will discuss the mechanisms involved in symptoms generation. Finally, we will discuss the similarities and differences between pediatric and adult GORD.

Do resistance exercises during biofeedback therapy enhance the anal sphincter and pelvic floor muscles in anal incontinence?

AIM

To determine if a biofeedback therapy that includes concentric resistance exercise for the anal sphincter muscles can improve muscle strength/function and improve AI symptoms compared to the traditional/non-resistance biofeedback therapy.

BACKGROUND

Biofeedback therapy is the current gold standard treatment for patients with anal incontinence (AI). Lack of resistance exercise biofeedback programs is a limitation in current practice.

METHODS

Thirty-three women with AI (mean age 60 years) were randomly assigned to concentric (resistance) or isometric (non-resistance) biofeedback training. Concentric training utilized the Functional Luminal Imaging Probe to provide progressive resistance exercises based on the patient's ability to collapse the anal canal lumen. Isometric training utilized a non-collapsible 10 mm diameter probe. Both groups performed a biofeedback protocol once per week in the clinic for 12 weeks and at home daily. High definition anal manometry was used to assess anal sphincter strength; symptoms were measured using FISI and UDI-6. 3D transperineal ultrasound imaging was used to assess the anal sphincter muscle integrity.

RESULTS

Concentric and isometric groups improved FISI and UDI-6 scores to a similar degree. Both the concentric and isometric groups showed small improvement in the anal high-pressure zone; however, there was no difference between the two groups. Ultrasound image analysis revealed significant damage to the anal sphincter muscles in both patient groups.

CONCLUSIONS

Concentric resistance biofeedback training did not improve the anal sphincter muscle function or AI symptoms beyond traditional biofeedback training. Anal sphincter muscle damage may be an important factor that limits the success of biofeedback training.

Pathophysiology of Dysphagia in Eosinophilic Esophagitis: Causes, Consequences, and Management

Eosinophilic esophagitis (EoE) is a leading cause of food bolus impaction in children and adults. The mechanism of dysphagia in EoE, particularly non-obstructive dysphagia, remains incompletely understood. While fibrostenotic processes appear to be critical in the development of dysphagia, somatosensory dysfunction and dysmotility also contribute. This review considers potential mechanisms of dysphagia and evaluates the utility of current and future treatment strategies in this context.

The Outcomes of Performing Partial Fundoplication Based on Endoflip Versus Manometric Findings

BACKGROUND

The surgical management of gastroesophageal reflux disease (GERD) involves extensive diagnostic studies and sophisticated surgical techniques. The workup should be comprehensive and purposeful. High resolution impedance manometry (HRIM) provides valuable information regarding peristalsis and lower esophageal sphincter relaxation. The disadvantages of HRIM such as intolerance or inability to pass the catheter led to its selective use or even omission especially in laparoscopic hiatal hernia repair with partial fundoplication. This pragmatic approach risks missing motility disorders in patients with secondary reflux symptoms related to achalasia or scleroderma. Endolumenal functional lumen imaging probe (endoFLIP) can fill this void as it evaluates the dynamics of the esophagogastric junction under sedation. This study aims to compare the outcomes of preoperative use of HRIM vs endoFLIP for laparoscopic repair of hiatal hernia with partial fundoplication.

METHODS

This is a retrospective cohort study for consecutive patients who underwent antireflux surgery with partial fundoplication between July 2018 and February 2021. Preoperative and postoperative outcomes were compared between two cohorts of patients: those with preoperative HRIM and those with preoperative endoFLIP.

RESULTS

A total of 72 patients were evaluated, 41 had preoperative HRIM and 31 had endoFLIP. There was no statistically significant difference in their age, sex, BMI, duration of GERD symptoms, or proton pump inhibitors use. The endoscopic findings of esophagitis, hiatal hernia, and Hill's grade were comparable. There was no difference in the American Society of Anesthesiology classification or the choice of antireflux surgery. The improvement of postoperative GERD scores and dysphagia subscore was similar between the two groups.

CONCLUSION

Performing partial fundoplication based on endoFLIP evaluation of the dynamics of the esophagogastric junction is safe and does not increase postoperative dysphagia compared to preoperative manometric use. Randomized prospective studies are needed to confirm the findings of this study.

Teaching EndoFLIP Impedance Planimetry to Practicing Endoscopists: An "Into the Fire" Approach to Simulation

Background. There are growing interests from practicing endoscopists to implement the functional lumen imaging probe (FLIP) impedance planimetry system. We present a simulation-based curriculum using an "into the fire" approach with hands-on pre- and post-tests to teach the use of this technology. Methods. The curriculum consists of a series of pre-tests, didactic content, mentored hands-on instructions, and post-tests. Pre- and post-testing included a knowledge-based written test, a confidence survey, and an assessment form specific to the hands-on performance of FLIP. Result. Twenty-two practicing physicians completed the curriculum. After course completion, participants had improved knowledge-based written test scores from 6.8±1.7 to 8.9±0.9 (P<0.001), confidence scores from 10.0±5.9 to 22.1±2.6 (P<0.001), and hands-on performance score from 11.4±3.4 to 23.1±2.0 (P<0.001) with significant improvement in all components of the hands-on skills. Conclusion. Our simulation curriculum is effective in improving confidence, knowledge, and technical proficiency when teaching the use of FLIP to practicing physicians.

Optional Management of Achalasia in 2021: Dilatation or Myotomy

Achalasia cardia is a primary motility disorder of the esophagus, defined by lack of normal esophageal peristalsis along with inadequate relaxation of lower esophageal sphincter . The mainstay of management in achalasia includes pneumatic dilatation, Heller’s myotomy and peroral endoscopic myotomy (POEM). Pneumatic dilatation and Heller’s myotomy have gained maturity over several decades. The current best practice with regard to pneumatic dilatation is graded and on-demand dilatation in appropriately selected cases with type I and II achalasia. Laparoscopic Heller’s myotomy plus partial fundoplication is minimally invasive with reduced postoperative reflux and has virtually replaced open Heller’s myotomy with or without fundoplication. The subtyping of achalasia using high-resolution manometry bears prognostic significance and may help in choosing appropriate therapeutic modality in these patients. Since all the three modalities are effective for type I and II achalasia, the choice among these depends on the availability, expertise, and patient’s preferences. On the other hand, POEM is more effective than pneumatic dilatation and Heller’s myotomy and, therefore, preferred in type III achalasia. Although POEM is effective across the spectrum of esophageal motility disorders, the incidence of gastroesophageal reflux is high and needs to be considered while choosing among various options in these patients. In cases with failed POEM, redo POEM appears to be effective in alleviating symptoms.

Bowel stiffness associated with histopathologic scoring of stenosis in patients with Crohn's disease

BACKGROUND AND AIMS

Intestinal stenosis is a common complication of Crohn's Disease (CD). Stenosis is associated with alteration of bowel mechanical properties. This study aims to quantitate the mechanical properties of the intestinal stenosis and to explore associations between histology and mechanical remodeling at stenotic intestinal sites in CD patients.

METHODS

Intestinal segments from stenotic sites were studied in vitro from 19 CD patients. A luminal catheter with a bag was used to stepwise pressurize the intestinal segments from 0-100 cmH₂O with 10 cmH₂O increments. B-mode ultrasound images were obtained at the narrowest part of the stenosis at each pressure level and morphometric parameters were obtained from ultrasound images. The mechanical behavior of the stenotic tissue were characterized by using an isotropic three dimensional strain energy function in Demiray model form, the mechanical constants were obtained by fitting the model to the recorded intraluminal pressure and the inner radius of the stenotic segment of the small bowel. Grading scores were used for histological analysis of inflammation, fibrosis, muscular hypertrophy and adipocyte proliferation in the intestinal layers. The collagen area fraction in intestinal layers was also calculated. Associations between histological and the mechanical constants (stiffness) were analyzed.

RESULTS

Chronic inflammation was mainly located in mucosa whereas fibrosis was found in submucosa. The mechanical remodeling was performed with changed mechanical constants ranged between 0.35-13.68kPa. The mechanical properties changes were associated mainly with chronic inflammation, fibrosis and combination of inflammation and fibrosis (R>0.69, P<0.001). Furthermore, the mechanical properties correlated with the collagen fraction in submucosa and muscular layers (R>0.53, P<0.05).

CONCLUSIONS

We quantitated the intestinal stenosis stiffness. Associations were found between bowel mechanical remodeling and histological changes at the stenotic site in CD patients.

STATEMENT OF SIGNIFICANCE

Although intestinal ultrasonography, CT and MRI can be used to diagnose Crohn's Disease (CD)-associated bowel strictures, these techniques may not have sufficient accuracy and resolution to differentiate predominantly inflammatory strictures from predominantly fibrotic strictures. The present study aims to quantitate the mechanical remodeling of intestinal stenosis and to explore the associations between histological parameters and mechanical properties at the intestinal stenotic sites in CD patients. For the first time, we quantitatively demonstrated that the mechanical properties of the intestinal wall in CD stenosis are associated with the chronic inflammation, fibrosis and collagen fraction in the intestinal layers. The results of this study may facilitate design and development of artificial biomaterials for gastrointestinal organs. The potential clinical implication of this study is that the histological characteristics in patients with CD can be predicted clinically by means of inflammation and fibrosis assessment in conjunction with tissue stiffness measurement.

Advanced Endoscopic Evaluation of Gastroesophageal Reflux Disease in Morbidly Obese Patients in a Rural Setting

INTRODUCTION

Obesity is a known risk factor for gastroesophageal reflux disease (GERD). Morbidly obese patients in rural areas are usually referred to the local surgeon for endoscopic evaluation. This situation poses significant challenges given the increased risk for perioperative complications due to anatomical and metabolic factors. This study aims to evaluate the safety of performing GERD diagnostic workup studies in a rural setting.

METHODS

Institutional review board approval was obtained for a retrospective chart review of patients who presented with GERD symptoms to a rural antireflux clinic between August 2015 and October 2020. Patients were included if their body mass index (BMI) was over 35 with comorbidities or over 40 kg/m² who underwent upper gastrointestinal endoscopy with or without concomitant placement of wireless pH probe and/or functional luminal imaging probe.

RESULTS

A total of 117 patients met the inclusion criteria. There were 94 (80.3%) females and 23(19.7%) males. The average age was 56.0 ± 13.4 years. The average BMI was 40.4 (35-66.4). Proton pump inhibitor use was noted in 97/117 (82.9%) with an average duration of 12.0 ± 9.2 years. The average GERD-Health Related Quality of Life, Reflux Symptom Index and GERD Symptom Score (GERSS) were 29.8 ± 20, 24.5 ± 14.2 and 21.3 ± 15.4 respectively. There were no procedural complications. All the endoscopic examinations were successfully completed and patients were discharged.

CONCLUSION

Performing diagnostic studies for GERD for morbidly obese patients in critical access hospitals is safe. Patient selection, proper training and adequate preparation are critical prerequisites for good outcomes.

Understanding the relationship between esophageal motor disorders and reflux disease

INTRODUCTION

The management of gastro-esophageal reflux disease (GERD) patients is often complex as the clinical presentation is heterogeneous and the mechanisms underlying symptoms are multifactorial. In the past decades, investigations conducted with conventional manometry and, above all, the more accurate high resolution manometry (HRM), helped us in exploring the field of esophageal motility and in understanding the link between motor features and GERD pathogenesis.

AREAS COVERED

Several studies carried out with conventional manometry and HRM have confirmed a relevant role of esophageal motor function in GERD pathogenesis. In particular, HRM studies have shown a direct correlation between impaired esophageal body motility, disruption of the esophagogastric junction and reflux burden. These findings impact the clinical and therapeutical management of GERD patients. Moreover, HRM findings might be helpful in evaluating patients with proton pump inhibitor (PPI) resistance and inconclusive evidences of GERD.

EXPERT OPINION

The relationship between esophageal motility and GERD pathogenesis needs to be further evaluated by multicenter outcome studies involving a large number of GERD patients and healthy controls. However, other more promising areas could be progressed.