Comparison of esophagogastric junction distensibility changes during POEM and Heller myotomy using intraoperative FLIP

Esophageal impedance planimetry during per-oral endoscopic myotomy guides myotomy extent

INTRODUCTION

Peroral endoscopic myotomy (POEM) is the standard treatment for achalasia. Functional luminal imaging probe (FLIP) technology enables objective measurement of lower esophageal sphincter (LES) geometry, with literature linking specific values to improved post-POEM outcomes. Our study assesses FLIP's intraoperative use in evaluating myotomy extent in real-time.

METHODS

Retrospective data from all patients undergoing POEM with intraoperative FLIP measurements were extracted from June 2020 to January 2023. The primary endpoint was intraoperative FLIP measurements, management changes, and symptom improvement (Eckardt score).

RESULTS

Fourteen patients (age 56 ± 14 years, BMI 28 ± 7 kg/m2) were identified. Most patients were female (64%). Predominantly, patients presented with type II achalasia (50%). FLIP measurements were taken before and after myotomy, demonstrating increases in mean distensibility index (DI) 1.6 ± 1. 4 to 5.4 ± 2.1 mm2/mmHg (p < 0.05) and mean diameter (Dmin) 6 ± 1.8 to 10.9 ± 2.3 mm (p < 0.05) at 50 ml balloon fill. Additional myotomy was performed in one patient when an inadequate increase in FLIP values were noted. Mean operative time was 98 ± 28 min, and there were no intraoperative complications. At the 30-day follow-up, median Eckardt score decreased from mean a preoperative score of 7 ± 2 to a post-operative mean of 2 ± 3, with 10 patients (78%) having a score ≤ 2. In total, four patients experienced symptom recurrence, with repeat FLIP values revealing a significant decrease in DI from 7 ± 2.2 post-POEM to 2.5 ± 1.5 at recurrence. FLIP technology identified LES pathology in 3 out of 4 (75%) patients, facilitating referral to LES-directed therapy.

CONCLUSION

Our study adds to the literature supporting the use of FLIP technology during the POEM procedure, with most patients achieving ideal values after a standard-length myotomy. This suggests the potential benefits of shorter myotomies guided by FLIP to achieve comparable outcomes and reduce postoperative GERD risk. Collaborative standardization of study designs and outcome measures is crucial for facilitating prospective trials and cross-setting outcome comparisons.

Early outcomes following EndoFLIP-tailored peroral endoscopic myotomy (POEM): the establishment of POEM services in two UK centers

Peroral endoscopic myotomy (POEM) is a safe and effective minimally invasive treatment for achalasia. Postoperative reflux rates remain high. The functional luminal imaging probe (FLIP) allows intraoperative measurement of lower esophageal distensibility during POEM. In theory, this enables a tailoring of myotomies to ensure adequate distensibility while minimizing postoperative reflux risk. Two prospectively collected POEM databases were analyzed from two UK tertiary upper GI centers. The operators in each center used FLIP measurements to ensure adequate myotomy. Outcome measures included Eckardt score (where <3 indicated clinical success) and proton-pump inhibitor use (PPI), collected at the first postoperative appointment. Length of stay was recorded as were complications. In all, 142 patients underwent POEM between 2015 and 2019. Overall, 90% (128/142) had postoperative Eckardt scores of <3 at 6 weeks. Clinical success improved to 93% (66/71) in the latter half of each series with a significantly higher rate of complete symptom resolution (53 versus 26%, P = 0.003). In all, 79% of the poor responders had previous interventions compared with 55% of responders (P = 0.09). Median post-myotomy distensibility index was 4.0 mm2/mmHg in responders and 2.9 in nonresponders (P = 0.16). Myotomy length of <7 cm was associated with 93% clinical success and 40% post op PPI use compared with 60% PPI use with longer myotomies. There were two type IIIa, two type IIIb, and one IV Clavien-Dindo complications. This is the largest series of endoluminal functional lumen imaging probe (EndoFLIP)-tailored POEM in the UK to date. The shorter myotomies, allowed through EndoFLIP tailoring, remained clinically effective at 6 weeks. Complete symptom response rates improved in the latter half of each series. More data will be needed from high-volume collaborations to decipher optimal myotomy profiles based on EndoFLIP parameters.

Virtual disease landscape using mechanics-informed machine learning: Application to esophageal disorders

Esophageal disorders are related to the mechanical properties and function of the esophageal wall. Therefore, to understand the underlying fundamental mechanisms behind various esophageal disorders, it is crucial to map mechanical behavior of the esophageal wall in terms of mechanics-based parameters corresponding to altered bolus transit and increased intrabolus pressure. We present a hybrid framework that combines fluid mechanics and machine learning to identify the underlying physics of various esophageal disorders (motility disorders, eosinophilic esophagitis, reflux disease, scleroderma esophagus) and maps them onto a parameter space which we call the virtual disease landscape (VDL). A one-dimensional inverse model processes the output from an esophageal diagnostic device called the functional lumen imaging probe (FLIP) to estimate the mechanical "health" of the esophagus by predicting a set of mechanics-based parameters such as esophageal wall stiffness, muscle contraction pattern and active relaxation of esophageal wall. The mechanics-based parameters were then used to train a neural network that consists of a variational autoencoder that generated a latent space and a side network that predicted mechanical work metrics for estimating esophagogastric junction motility. The latent vectors along with a set of discrete mechanics-based parameters define the VDL and formed clusters corresponding to specific esophageal disorders. The VDL not only distinguishes among disorders but also displayed disease progression over time. Finally, we demonstrated the clinical applicability of this framework for estimating the effectiveness of a treatment and tracking patients' condition after a treatment.

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.

Changes in Distensibility Index During an Incremental POEM Myotomy

BACKGROUND

A longer myotomy for the treatment of achalasia is associated with worse gastroesophageal reflux disease despite palliating dysphagia. Recently, clinical outcomes have been correlated to the distensibility of the distal esophagus, which is measured intra-operatively using an endoscopic functional luminal image probe (EndoFLIP). We aimed to determine the minimum per oral endoscopic myotomy (POEM) length to allow for adequate distensibility index (DI).

METHODS

A 6-cm myotomy conducted in 2-cm increments during POEM was performed for patients with achalasia I and II from 2017 to 2019. The EndoFLIP was used to measure the DI intra-operatively: (1) prior to intervention, (2) following creation of the submucosal tunnel, (3) following transection of the high-pressure zone (HPZ), (4) following the distal extension, and (5) following the proximal esophageal extension.

RESULTS

A total of 16 patients underwent POEM. Ages ranged from 21 to 78 years, 10 were male, and 13 had type II achalasia. The median DI was 2.7 (1.4-3.6) mm²/mmHg prior to intervention; 2.4 (1.4-3.3) mm²/mmHg following the submucosal tunnel; 3.2 (1.6-4.4) mm²/mmHg following transection of the HPZ; 3.8 (2.6-4.5) mm²/mmHg following the gastric extension; and 4.5 (3.3-7.1) mm²/mmHg following the proximal extension. Our target range DI was achieved for 50% of patients after transection of the HPZ.

CONCLUSIONS

Distensibility changed with each myotomy increment and fell within the target range for most patients following a 2-4-cm myotomy. This suggests that a shorter myotomy may be appropriate for select patients, and the use of the EndoFLIP intra-operatively may allow for a tailored myotomy length.

The Utility of Functional Luminal Imaging Probes Measurements to Diagnose Dysmotility and Their Relationship to Impaired Bolus Clearance

BACKGROUND

Functional luminal imaging probes (FLIP) have been used by multiple centers to assess esophagogastric junction (EGJ) function in patients at risk for esophageal obstruction but its role in diagnosing peristaltic disorders is less well studied. In particular, there are no studies comparing the sensitivity of FLIP to diagnose motility abnormalities and impaired bolus transit by high-resolution esophageal manometry with impedance.

METHODS

We prospectively recruited 42 patients undergoing high-resolution esophageal manometry with impedance (HRIM) who also underwent FLIP between 2018 and 2020. HRIM parameters were analyzed using Swallow Gateway software to determine peristaltic and lower esophageal sphincter pressure measurements as well as bolus flow parameters. FLIP tracings were analyzed for the presence of repetitive antegrade contractions (RACs), EGJ distensibility, and associated parameters.

RESULTS

Forty-two patients were included (11 controls, 7 achalasia, 16 fundoplication, 8 dysmotility). The mean age of patients was 10.1 ± 0.9 years. There were significant differences in bolus flow parameters across diagnosis with longer bolus presence (BPT) in control patients compared with fundoplication and dysmotility patients. There was a significant correlation between EGJ diameter, EGJ distensibility and bolus flow time (BFT) for solid foods (r2 > 0.518, P < 0.02). The presence of RACs and EGJ relaxation during RACs was associated with a greater BFT and BPT across textures (P < 0.05). Forty-two percentage of patients with absent RACs, however, had clear peristalsis by HRIM.

CONCLUSIONS

The presence of RACs and EGJ relaxation by FLIP correlate with improved bolus flow. Patients with an absence of RACs need HRIM to confirm any diagnoses of dysmotility.

Functional Luminal Imaging Probe in the Management of Pediatric Esophageal Disorders

BACKGROUND

Functional luminal imaging probe (FLIP) measures pressure-geometry relationships of digestive luminal space. When used in esophageal disorders, it provides several luminal parameters that help better understand the pathophysiology. Data about the potential utility of FLIP in pediatrics are scarce and there is no standardized use in children. We aim to describe the use of FLIP in our center, its safety, feasibility, and clinical impact in esophageal disorders in children.

METHODS

Consecutive FLIP recordings performed at the Centre Hospitalier Universitaire-Sainte-Justine, Montréal, Canada between February 2018 and January 2021 were extracted. A chart review was conducted for demographics and medical history. Symptomatology after the procedure was evaluated with validated dysphagia scores.

KEY RESULTS

Nineteen patients were included (11 girls, median age 16 years, range 3.2-19.6) with achalasia (n = 5), post-Heller's myotomy dysphagia (n = 3), esophagogastric junction outflow obstruction (n = 3), congenital esophageal stenosis (n = 2); post-esophageal atresia repair stricture (n = 3), and post-fundoplication dysphagia (n = 3). There was no significant correlation between integrated relaxation pressure measured with high resolution manometry and distensibility index (DI). The use of FLIP made it possible to differentiate between dysphagia related to an esophageal obstruction (DI < 2.8 mm2/mmHg) and dysphagia without major motility disorder (DI > 2.8 mm2/mmHg) that guided the indication for dilation. FLIP led to a change in management in 47% of the patients. Forty-seven percent of the patients were symptom free at the time of the evaluation.

CONCLUSIONS INFERENCES

FLIP provides key esophageal luminal values and therefore can play an important role in pediatric esophageal disorders management.

Devices for esophageal function testing

BACKGROUND AND AIMS

Esophageal function testing is an integral component of the evaluation of refractory GERD and esophageal motility disorders. This review summarizes the current technologies available for esophageal function testing, including the functional luminal imaging probe (FLIP), high-resolution esophageal manometry (HRM), and multichannel intraluminal impedance (MII) and pH monitoring.

METHODS

We performed a MEDLINE, PubMed, and MAUDE database literature search to identify pertinent clinical studies through March 2021 using the following key words: esophageal manometry, HRM, esophageal impedance, FLIP, MII, and esophageal pH testing. Technical data were gathered from traditional and web-based publications, proprietary publications, and informal communications with pertinent vendors. The report was drafted, reviewed, and edited by the American Society for Gastrointestinal Endoscopy Technology Committee and approved by the Governing Board of the American Society for Gastrointestinal Endoscopy.

RESULTS

FLIP is a high-resolution impedance planimetry system used for pressure and dimension measurement in the esophagus, pylorus, and anal sphincter. FLIP provides complementary information to HRM for esophageal motility disorders, especially achalasia. The Chicago classification, based on HRM data, is a widely adopted algorithmic scheme used to diagnose esophageal motility disorders. MII detects intraluminal bolus movement and, combined with pH measurement or manometry, provides information on acid and non-acid gastroesophageal reflux and bolus transit in patients with refractory GERD and for preoperative evaluation for anti-reflux procedures.

CONCLUSIONS

Esophageal function testing techniques (FLIP, HRM, and MII-pH) have diagnostic and prognostic value in the evaluation of esophageal motility disorders and refractory GERD. Newer technologies and classification systems have enabled an increased understanding of these diseases.

Comparison of preoperative, intraoperative, and follow-up functional luminal imaging probe measurements in patients undergoing myotomy for achalasia

BACKGROUND AND AIMS

The functional luminal imaging probe (FLIP) is a novel catheter-based device that measures esophagogastric junction (EGJ) distensibility index (DI) in real time. Previous studies have demonstrated DI to be a predictor of post-treatment clinical outcomes in patients with achalasia. We sought to evaluate EGJ DI in patients with achalasia before, during, and after peroral endoscopic myotomy (POEM) and laparoscopic Heller myotomy (LHM) and to assess the correlation of DI with postoperative outcomes.

METHODS

DI (defined as the minimum cross-sectional area at the EGJ divided by distensive pressure) was measured at 4 time points in patients undergoing surgical myotomy for achalasia: (1) during outpatient preoperative endoscopy (preoperative DI), (2) at the start of each operation after the induction of anesthesia (induction DI), (3) at the conclusion of each operation (postmyotomy DI), and (4) at routine follow-up endoscopy 12 months postoperatively (follow-up DI). Routine Eckardt symptom score, endoscopy, timed barium esophagram, and pH study were obtained 12 months postoperatively.

RESULTS

Forty-six patients (35 POEM, 11 LHM) underwent FLIP measurements at all 4 time points. Preoperative and induction mean DI were similar for both groups (POEM, 1 vs .9 mm²/mm Hg; LHM, 1.7 vs 1.5 mm²/mm Hg). POEM resulted in a significant increase in DI (induction .9 vs postmyotomy 7 mm²/mm Hg, P < .001). There was a subsequent decrease in DI in the follow-up period (postmyotomy 7 vs follow-up 4.8 mm²/mm Hg, P < .01), but DI at follow-up was still significantly improved from preoperative values (P < .001). For LHM patients, DI also increased as a result of surgery (induction 1.5 vs postmyotomy 5.9 mm²/mm Hg, P < .001); however, the increase was smaller than in POEM patients (DI increase 4.4 vs 6.2 mm²/mm Hg, P < .05). After LHM, DI also decreased in the follow-up period, but this change was not statistically significant (5.9 vs 4.4 mm²/mm Hg, P = .29). LHM patients with erosive esophagitis on follow-up endoscopy had a significantly higher postmyotomy DI compared with those without esophagitis (9.3 vs 4.8 mm²/mm Hg, P < .05).

CONCLUSIONS

EGJ DI improved dramatically as a result of both POEM and LHM, with POEM resulting in a larger increase. Mean DI decreased at intermediate follow-up but remained well above previously established thresholds for symptom recurrence. DI at the conclusion of LHM was predictive of erosive esophagitis in the postoperative period, which supports the potential use of FLIP for calibration of partial fundoplication construction during LHM.

Impedance planimetry values for predicting clinical response following peroral endoscopic myotomy

BACKGROUND

There is growing interest in developing impedance planimetry as a tool to enhance the clinical outcomes for endoscopic and surgical management of achalasia. The primary aim of this study was to determine whether impedance planimetry measurements can predict clinical response and reflux following peroral endoscopic myotomy (POEM).

METHODS

A multicenter cohort study of patients with achalasia undergoing POEM was established from prospective databases and retrospective chart reviews. Patients who underwent impedance planimetry before and after POEM were included. Clinical response was defined as an Eckardt score of ≤ 3. Tenfold cross-validated area under curve (AUC) values were established for the different impedance planimetry measurements associated with clinical response and reflux development.

RESULTS

Of the 290 patients included, 91.7 % (266/290) had a clinical response and 39.4 % (108/274) developed reflux following POEM. The most predictive impedance planimetry measurements for a clinical response were: percent change in cross-sectional area (%ΔCSA) and percent change in distensibility index (%ΔDI), with AUCs of 0.75 and 0.73, respectively. Optimal cutoff values for %ΔCSA and %ΔDI to determine a clinical response were a change of 360 % and 272 %, respectively. Impedance planimetry values were much poorer at predicting post-POEM reflux, with AUCs ranging from 0.40 to 0.62.

CONCLUSION

Percent change in CSA and distensibility index were the most predictive measures of a clinical response, with a moderate predictive ability. Impedance planimetry values for predicting reflux following POEM showed weak predictive capacity.

Insights into the endoscopic management of esophageal achalasia

Achalasia is a primary esophageal motility disorder characterized by the loss of inhibitory neurons in the myenteric plexus, resulting in impaired relaxation of the esophagogastric junction. Achalasia is an incurable disease, and the treatment modalities are aimed at disruption of the esophagogastric junction and vary widely from pharmacological to endoscopic to surgical. Traditional endoscopic therapy includes pneumatic dilation, botulinum toxin injection, and peroral endoscopic myotomy. This review aims to provide an overview of the endoscopic management of achalasia, while focusing on the utilization of peroral endoscopic myotomy and other novel approaches.

Intraoperative diagnosis and treatment of Achalasia using EndoFLIP during Heller Myotomy and Dor fundoplication

BACKGROUND

Manometry is the gold standard diagnostic test for achalasia. However, there are incidences where manometry cannot be obtained preoperatively, or the results of manometry is inconsistent with the patient's symptomatology. We aim to determine if intraoperative use of EndoFLIP can provide a diagnosis of achalasia and provide objective information during Heller myotomy and Dor fundoplication.

METHODS

To determine the intraoperative diagnostic EndoFLIP values for patients with achalasia, we determined the optimal cut-off points of the distensibility index (DI) between patients with a diagnosis of achalasia and patients with a diagnosis of hiatal hernia. To evaluate the usefulness of EndoFLIP values during Heller myotomy and Dor fundoplication, we obtained a cohort of patients with EndoFLIP values obtained after Heller myotomy and after Dor fundoplication as well as Eckardt score before and after surgery.

RESULTS

Our analysis of 169 patients (133 hiatal hernia and 36 achalasia) showed that patients with DI < 0.8 have a >99% probability of having achalasia, while DI > 2.3 have a >99% probability of having hiatal hernia. Patients with a DI 0.8-1.3 have a 95% probability of having achalasia, and patients with a DI of 1.4-2.2 have a 94% probability of having a hiatal hernia. There were 40 patients in the cohort to determine objective data during Heller myotomy and Dor fundoplication. The DI increased from a median of 0.7 to 3.2 after myotomy and decreased to 2.2 after Dor fundoplication (p < 0.001). The median Eckardt score went down from a median of 4.5 to 0 (p < 0.001).

CONCLUSIONS

Our study shows that intraoperative use of EndoFLIP can facilitate the diagnosis of achalasia and is used as an adjunct to diagnose achalasia when symptoms are inconsistent. The routine use of EndoFLIP during Heller myotomy and Dor fundoplication provides objective data during the operation in a group of patients with excellent short-term outcomes.

Estimation of mechanical work done to open the esophagogastric junction using functional lumen imaging probe panometry

In this study, we quantify the work done by the esophagus to open the esophagogastric junction (EGJ) and create a passage for bolus flow into the stomach. Work done on the EGJ was computed using functional lumen imaging probe (FLIP) panometry. Eighty-five individuals underwent FLIP panometry with a 16-cm catheter during sedated endoscopy including asymptomatic controls (n = 14), 45 patients with achalasia (n = 15 each, three subtypes), those with gastroesophageal reflux disease (GERD; n = 13), those with eosinophilic esophagitis (EoE; n = 8), and those with systemic sclerosis (SSc; n = 5). Luminal cross-sectional area (CSA) and pressure were measured by the FLIP catheter positioned across the EGJ. Work done on the EGJ (EGJW) was computed (millijoules, mJ) at 40-mL distension. Additionally, a separate method was developed to estimate the "work required" to fully open the EGJ (EGJROW) when it did not open during the procedure. EGJW for controls had a median [interquartile range (IQR)] value of 75 (56-141) mJ. All achalasia subtypes showed low EGJW compared with controls (P < 0.001). Subjects with GERD and EoE had EGJW 54.1 (6.9-96.3) and 65.9 (10.8-102.3) mJ, similar to controls (P < 0.08 and P < 0.4, respectively). The scleroderma group showed low values of EGJW, 12 mJ (P < 0.001). For patients with achalasia, EGJROW was the greatest and had a value of 210.4 (115.2-375.4) mJ. Disease groups with minimal or absent EGJ opening showed low values of EGJW. For patients with achalasia, EGJROW significantly exceeded EGJW values of all other groups, highlighting its unique pathophysiology. Balancing the relationship between EGJW and EGJROW is potentially useful for calibrating achalasia treatments and evaluating treatment response.NEW & NOTEWORTHY Changes in pressure and diameter occur at the EGJ during esophageal emptying. Similar changes can be observed during FLIP panometry. Data from healthy and diseased individuals were used to estimate the mechanical work done on the EGJ during distension-induced relaxation or, in instances of failed opening, work required to open the EGJ. Quantifying these parameters is potentially valuable to calibrate treatments and gauge treatment efficacy for subjects with disorders of EGJ function, especially achalasia.

Advances and caveats in modern achalasia management

Achalasia is a rare esophageal motility disorder characterized by the incomplete relaxation of the lower esophageal sphincter (LES) and impaired peristaltic activity. The advent of high-resolution manometry (HRM) and the rapidly evolving role of therapeutic endoscopy have revolutionized the approach to the diagnosis and management of achalasia patients in the last decade. With advances in HRM technology and methodology, fluoroscopy and EndoFlip, achalasia can be differentiated into therapeutically meaningful phenotypes with a high degree of accuracy. Further, the newest treatment option, per-oral endoscopic myotomy (POEM), has become a staple therapy following the last 10 years of experience, and recent randomized trials appear to show no difference between POEM, graded pneumatic dilatation and surgical Heller myotomy in terms of short- and long-term efficacy or complication rate. On the other hand, how treatment outcomes are measured as well as the risk of reflux following therapy remain areas of contention. This review aims to summarize the recent advancements in achalasia testing and therapy, describes the recent randomized clinical trials as well as their potential setbacks, and touches on the future of personalizing achalasia treatment.

Use of the Functional Lumen Imaging Probe in Clinical Esophagology

The functional lumen imaging probe (FLIP) measures luminal dimensions using impedance planimetry, performed most often during sedated upper endoscopy. Mechanical properties of the esophageal wall and opening dynamics of the esophagogastric junction (EGJ) can be objectively evaluated in esophageal motor disorders, eosinophilic esophagitis, esophageal strictures, during esophageal surgery and in postsurgical symptomatic states. Distensibility index, the ratio of EGJ cross sectional area to intraballoon pressure, is the most useful FLIP metric. Secondary peristalsis from balloon distension can be displayed topographically as repetitive anterograde or retrograde contractile activity in the esophageal body, similar to high-resolution manometry. Real-time interpretation and postprocessing of FLIP metadata can complement the identification of esophageal outflow obstruction and achalasia, especially when findings are inconclusive from alternate esophageal tests in symptomatic patients. FLIP can complement the diagnosis of achalasia when manometry and barium studies are inconclusive or negative in patients with typical symptoms. FLIP can direct adequacy of disruption of the EGJ in achalasia when used during and immediately after myotomy and pneumatic dilation. Lumen diameter measured using FLIP in eosinophilic esophagitis and in complex strictures can potentially guide management. An abbreviated modification of the Grading of Recommendations Assessment, Development, and Evaluation was used to determine the quality of available evidence and recommendations regarding FLIP utilization. FLIP metrics that are diagnostic or suggestive of an abnormal motor pattern and metrics that define normal esophageal physiology were developed by consensus and are described in this review.

Using a standardized intra-operative endoflip protocol during fundoplication to identify factors that affect distensibility

INTRODUCTION

The Endoluminal Functional Lumen Imaging Probe (Endoflip) can be used to provide objective measurements of the gastroesophageal junction during fundoplication, and recent publications have suggested that this device could improve surgical outcomes. However, the impact of operative variables has not been clearly reported. The aim of this study is to determine the effect of these variables on functional lumen imaging probe (FLIP) measurements.

METHODS

Following implementation of a standardized operative FLIP protocol, all data were collected prospectively and entered into a quality database. This database was queried for patients undergoing hiatal hernia repair and fundoplication. The protocol utilized various balloon volumes (30 and 40 ml), patient positions (flat and reverse Trendelenburg) and amounts of insufflation (15 mmHg pneumoperitoneum and no pneumoperitoneum).

RESULTS

Between August 2018 and February 2020, 97 fundoplications were performed by a single surgeon. Multivariable analysis without interactions demonstrated that a 40 ml volume fill resulted in significantly higher minimum diameter (Dmin), cross-sectional area (CSA), intra-balloon pressure (IBP) and distensibility index (DI) compared to a 30 ml volume fill (p < 0.001). While reverse Trendelenburg positioning resulted in a significantly higher Dmin, IBP and CSA compared to the flat position (all p < 0.05), there was little impact of positioning on DI. Lastly, pneumoperitoneum significantly increased IBP (p < 0.001) but did not affect Dmin (p = 0.697) or CSA (p = 0.757), which resulted in a significant decrease in DI (p < 0.001) when compared to measurements without pneumoperitoneum. Multivariable analysis allowing for interactions demonstrated significant two-way interactions between balloon volume and pneumoperitoneum (p = 0.047), as well as patient position and pneumoperitoneum (p < 0.001).

CONCLUSION

Surgeons should consider balloon volume and the presence or absence of pneumoperitoneum when interpreting distensibility during or after fundoplication. Additionally, we suggest a formal standardized protocol for FLIP measurements to utilize a 40 ml volume fill in reverse Trendelenburg without pneumoperitoneum.

ACG Clinical Guidelines: Clinical Use of Esophageal Physiologic Testing

Esophageal symptoms are common and may indicate the presence of gastroesophageal reflux disease (GERD), structural processes, motor dysfunction, behavioral conditions, or functional disorders. Esophageal physiologic tests are often performed when initial endoscopic evaluation is unrevealing, especially when symptoms persist despite empiric management. Commonly used esophageal physiologic tests include esophageal manometry, ambulatory reflux monitoring, and barium esophagram. Functional lumen imaging probe (FLIP) has recently been approved for the evaluation of esophageal pressure and dimensions using volumetric distension of a catheter-mounted balloon and as an adjunctive test for the evaluation of symptoms suggestive of motor dysfunction. Targeted utilization of esophageal physiologic tests can lead to definitive diagnosis of esophageal disorders but can also help rule out organic disorders while making a diagnosis of functional esophageal disorders. Esophageal physiologic tests can evaluate obstructive symptoms (dysphagia and regurgitation), typical and atypical GERD symptoms, and behavioral symptoms (belching and rumination). Certain parameters from esophageal physiologic tests can help guide the management of GERD and predict outcomes. In this ACG clinical guideline, we used the Grading of Recommendations Assessment, Development and Evaluation process to describe performance characteristics and clinical value of esophageal physiologic tests and provide recommendations for their utilization in routine clinical practice.

The use of impedance planimetry (Endoscopic Functional Lumen Imaging Probe, EndoFLIP® ) in the gastrointestinal tract: A systematic review

BACKGROUND AND PURPOSE

The EndoFLIP® system is a method of delineating impedance and was first designed to investigate the characteristics of the esophago-gastric junction. In the last decade, its use was widened to investigate other sphincteric and non-sphincteric systems of the gastrointestinal tract. The objective of the present systematic review was to summarize the available data in literature on the use of the EndoFLIP® system in the gastrointestinal tract, including sphincteric and non-sphincteric regions. We performed a systematic review in accordance with recommendations for systematic review using PRISMA guidelines without date restriction, until June 2020, using MEDLINE-PubMed, Cochrane Library, and Google Scholar databases. Only articles written in English were included in the present review. Five hundred and six unique citations were identified from all database combined. Of those, 95 met the inclusion criteria. There was a lack of standardization among studies in terms of anesthetic drugs use, probe placement, and inflation protocol. In most cases, only small cohorts of patients were included. Most studies investigated the EGJ, with a potential use of the EndoFLIP® to identify a subgroup of patients with achalasia and for intraoperative assessment of treatment efficacy in achalasia. However, the use of EndoFLIP® in the esophageal body (esophageal panometry), other esophageal diseases (gastro-esophageal reflux disease, eosinophilic esophagitis), and other sphincter regions (anal canal, pylorus) will need further confirmatory studies. The EndoFLIP® system provides detailed geometric data of the gastrointestinal lumen but further works are needed to determine its use in clinical practice.

Esophageal Functional Lumen Imaging Probe (FLIP): How Can FLIP Enhance Your Clinical Practice?

Recent innovations in esophageal diagnostic testing have enhanced gastroenterology clinical practice by facilitating more nuanced and advanced evaluation of esophageal symptoms. Among these pivotal advances is the FDA-approved functional lumen imaging probe (FLIP), which utilizes impedance planimetry via volumetric distension of a catheter-mounted balloon at the time of sedated upper endoscopy, to acquire esophageal dimensions and pressures. In real time, FLIP can display cross-sectional areas (CSA) and distensibility indices (ratios of CSA to intra-balloon pressures) throughout the esophagus, most notably at the esophagogastric junction, as well as secondary peristaltic esophageal body contractile patterns. As the use of FLIP has progressively spread and permeated into the practice of clinical gastroenterology since its introduction, increasing data on and experiences with its applications have accumulated to guide its utility in clinical practice. In this current review developed for gastroenterologists and foregut surgeons across clinical practice, we provide an introduction to FLIP technology and metrics and discuss the clinical scenarios in which performance of or referral for FLIP may be helpful in the evaluation and management of patients with commonly encountered esophageal symptoms and disorders. Specifically, we discuss the potential applications and limitations of FLIP as a complementary diagnostic modality in patients with non-obstructive dysphagia, established or suspected achalasia spectrum disorders, eosinophilic esophagitis, gastroesophageal reflux disease and those undergoing esophageal surgery.

The functional lumen imaging probe in gastrointestinal disorders: the past, present, and future

The functional lumen imaging probe (FLIP) is a diagnostic tool that utilizes impedance planimetry to allow the assessment of luminal diameter and distensibility. It has been used primarily in esophageal diseases, in particular, in the assessment of achalasia, esophagogastric junction outflow obstruction, and eosinophilic esophagitis (EoE). The usage and publications have increased over the past decade and it is now an essential tool in the armamentarium of the esophagologist. Indications are emerging outside of the esophagus, in particular with regard to gastroparesis. Our paper will review the history of FLIP, optimal current usage, data for key esophageal disorders (including achalasia, reflux, and EoE), data for nonesophageal disorders, and our sense as to whether FLIP is ready for prime time, as well as gaps in evidence and suggestions for future research.

Intraoperative use of FLIP is associated with clinical success following POEM for achalasia

BACKGROUND

Esophagogastric junction distensibility index (DI), measured using the functional luminal imaging probe (FLIP), correlates with symptomatic outcomes after interventions for achalasia. The objective of this study was to determine if the intraoperative measurement of DI using FLIP was associated with improved clinical outcomes following per-oral endoscopic myotomy (POEM) for achalasia when compared with procedures in which FLIP was not utilized.

METHODS

Patients undergoing POEM from 2012 to 2017 at a single institution by a single surgeon were studied. Use of FLIP during this time period was based on catheter and technician availability, resulting in two patient cohorts. In patients in whom FLIP was used, operative video recordings were reviewed to determine when DI measurements led to the performance of additional myotomy. Postoperative Eckardt symptom scores (ES) at 12 months and postoperative physiologic studies were compared between patients with and without intraoperative FLIP. Associations were assessed using Mann-Whitney U and Chi-square tests.

RESULTS

143 patients were included in the analysis (61 with intraoperative FLIP and 82 without FLIP). Video recordings were available for 85% of the FLIP cohort. Review of these operative recordings revealed that 65% of patients who underwent FLIP had additional myotomy performed following the initial postmyotomy FLIP measurement. At 12 months after POEM, the FLIP cohort had significantly more clinical successes (defined as ES ≤ 3) than patients in whom FLIP was not used (93% vs. 81%, p < 0.05).

CONCLUSIONS

Use of intraoperative FLIP during POEM resulted in the surgeon performing additional myotomy in over half of cases and was associated with improved clinical outcomes. This study demonstrates the potential for a FLIP-tailored myotomy to improve outcomes in patients undergoing surgical myotomy for achalasia.

Intraoperative FLIP distensibility during POEM varies according to achalasia subtype

BACKGROUND

The functional luminal imaging probe (FLIP) can be used to measure the esophagogastric junction distensibility index (DI) during myotomy for achalasia and increased DI has been shown to predict superior clinical outcomes. The objective of this study was to determine if the intraoperative DI and the changes produced by per oral endoscopic myotomy (POEM) differed between achalasia subtypes.

METHODS

FLIP measurements were performed during POEM for achalasia at a single institution. DI (defined as the minimum cross-sectional area (CSA) at the EGJ divided by distensive pressure) was measured at three time points: after induction of anesthesia, after submucosal tunneling, and after myotomy. Measurements were reported at the 40 mL fill volume for the 8 cm FLIP (EF-325) and at the 60 mL fill volume for the 16 cm FLIP (EF-322). Measurements were compared using chi-square and Kruskal-Wallis tests.

RESULTS

142 patients had intraoperative FLIP performed during POEM for achalasia between 2012 and 2019 (30 type I, 68 type II, 27 type III, and 17 variant). Patients with type I achalasia had a significantly higher induction DI (median 1.7 mm²/mmHg) than type II (0.8 mm²/mmHg), type III (0.9 mm²/mmHg), and variants (1.1 mm²/mmHg; p < 0.001). These differences persisted after submucosal tunneling and final DI after myotomy was also significantly higher in type I patients (median 8.0 mm²/mmHg) compared to type II (5.8 mm²/mmHg), type III (3.9 mm²/mmHg), and variants (5.4 mm²/mmHg; p < 0.001). Achalasia subtypes were found to have similar CSA at all time points, whereas pressure differed with type I having the lowest pressure and type III the highest.

CONCLUSION

The DI at each operative step during POEM was found to differ significantly between achalasia subtypes. These differences in DI were due to pressure, as CSA was similar between subtypes. Achalasia subtype should be accounted for when using FLIP as an intraoperative calibration tool and in future studies examining the relationship between DI and clinical outcomes.

Impedance in the evaluation of the esophagus

The aim of this paper is to review esophageal electrical impedance technologies and to discuss the use of these technologies for physiological measurements, diagnostics, and therapy of esophageal disease. In order to develop a better understanding of the pathophysiology of and improve the diagnosis of esophageal disorders, such as gastroesophageal reflux disease (GERD) and achalasia, several new diagnostic tests, including intraluminal impedance, esophageal mucosal impedance, and the functional luminal imaging probe, have been developed. These technologies have proven valuable for assessment of the esophagus in recent years. They provide information on esophageal flow properties, mucosal integrity, lumen shape, and distensibility in esophageal disorders, in particular for GERD and achalasia. Despite their promise and novel clinical studies, the potential of these technologies has been far from realized. New multidisciplinary approaches will contribute to our understanding and interpretation of esophageal impedance data and disease mechanisms.

Clinical usefulness of esophagogastric junction distensibility measurement in patients with achalasia before and after peroral endoscopic myotomy

BACKGROUND/AIMS

This study aimed to determine the clinical efficacy of measuring the esophagogastric junction (EGJ) distensibility index (DI) in patients with achalasia before and after peroral endoscopic myotomy (POEM).

MATERIALS AND METHODS

Retrospective data were collected from 195 patients who underwent POEM from November 2014 to November 2017 at our clinic. The Eckardt score, high-resolution manometry, and EGJ distensibility were measured before and six months after POEM. Treatment failure was defined as a postprocedure Eckardt score >3 or patients who underwent repeat POEM.

RESULTS

The DI (mm2/mmHg) before and after POEM was 3.42±3.55 and 11.57±6.64, respectively (p<0.01). There was no difference in the DI between achalasia subtypes I, II, and III (11.45±6.24 versus 15.49±11.53 versus 13.27±9.49, p=0.22) or previous treatment history (15.39±10.85 versus 11.10±7.25, p=0.20). The DI was higher in patients with reflux esophagitis after POEM, but the difference was not significant (13.59±7.15 versus 12.54±10.9, p=0.571).

CONCLUSION

This study showed that EGJ distensibility measurement is useful to assess post-POEM outcomes. These findings suggest that the functional lumen imaging probe may be a useful method for assessing clinical efficacy of POEM in patients with achalasia. However, this is a costly procedure that requires experience.

Intraoperative use of a functional lumen imaging probe during peroral endoscopic myotomy in patients with achalasia: A single-institute experience and systematic review

Aim

The functional lumen imaging probe (FLIP) is a recently developed technique to evaluate the esophagogastric junction (EGJ) distensibility. Unlike timed barium esophagogram (TBE) and high-resolution manometry (HRM), FLIP can be used during peroral endoscopic myotomy (POEM). The aim of this study was to evaluate the association of intraoperative FLIP parameters with clinical outcomes as recorded in a single-center database and to investigate a systematic review of literatures.

Methods

We reviewed consecutive patients diagnosed with achalasia and scheduled for POEM between June 2016 and March 2019 in our tertiary referral hospital. All patients underwent intraoperative FLIP assessment during POEM. The final FLIP measurements were compared between the patients with good and poor clinical response. We comprehensively reviewed studies evaluating whether intraoperative FLIP measurements reflected clinical outcomes.

Results

We evaluated 23 patients with achalasia who underwent intraoperative FLIP before and after POEM. Two exhibited poor clinical responses after 3 months (Eckardt scores = 3). The final distensibility index (DI) did not differ significantly between good and poor responders (5.01 [4.52] vs. 4.91 [3.63–6.20] mm²/mmHg at a balloon distension of 50-mL, median [IQR], P = 0.853). The final DI did not differ significantly between post-POEM reflux esophagitis and non-reflux esophagitis groups (6.20 [5.15] vs. 4.23 [1.79] mm²/mmHg at a balloon distension of 50-mL, median [IQR], P = 0.075).

Conclusions

A systematic review of both prospective and retrospective studies including our data indicated that the final intraoperative FLIP measurements did not differ significantly between good and poor responders. Further study with more patients is necessary to explore whether FLIP can predict short- and long-term clinical responses.

Functional Luminal Imaging Probe Assessment in Postfundoplication Patients Changes Management Beyond Manometry

OBJECTIVES

Fundoplication is a commonly performed pediatric surgery but the surgery can result in nonspecific symptoms that merit further evaluation. The goal of this study was to determine the utility of Functional Luminal Imaging Probe (FLIP) compared with high-resolution manometry with impedance (HRIM) in the evaluation of fundoplication symptoms.

METHODS

We reviewed the FLIP and HRIM tracings of symptomatic fundoplication patients. We compared FLIP results of fundoplication patients to those of pediatric achalasia and control patients. We also compared the role of FLIP to HRIM in clinical decision-making and clinical outcomes.

RESULTS

EGJ distensibilities of fundoplication patients ranged from 0.6 to 8.2 mm/mmHg. Because of the different pediatric patient sizes (8.9--73.5 kg), balloon size inflations varied but, after adjusting balloon fill volume by weight, there was a linear relationship between inflation and distensibility. When compared with control patients and achalasia patients, distensibilities of fundoplication patients were lower than control patients and higher than achalasia patients (P = 0.0001). Patients who had an EGJ intervention had a mean EGJ distensibility of 2.3 ± 1.1 mm/mmHg compared with 5.1 ± 1.6 mm/mmHg in medically managed patients (P = 0.0001). Patients who had an esophagogastric junction (EGJ) intervention had a mean IRP of 13.9 ± 6.1 mmHg compared with medically managed patients who had a mean IRP of 9.9 ± 3.9 mmHg (P = 0.3).

CONCLUSIONS

We show FLIP may provide additional insight into EGJ physiology in symptomatic fundoplication patients and complements HRIM.

Three-Dimensional High-Resolution Esophageal Manometry Study of the Esophagogastric Junction in Patients with Achalasia

BACKGROUND

A novel three-dimensional high-resolution esophageal manometry provides a dynamic 360° representation of the pressure at the esophagogastric junction.

AIMS

To describe the three-dimensional high-resolution esophageal manometry patterns of achalasia.

METHODS

We retrospectively included all consecutive patients who underwent three-dimensional high-resolution esophageal manometry before and after treatment (pneumatic dilatation or per-oral endoscopic myotomy) for achalasia between November 2016 and July 2017. The distribution of the pressures at the esophagogastric junction on three-dimensional high-resolution esophageal manometry was determined.

RESULTS

Eighteen patients were included. Mean integrated relaxation pressure was 20.7 mmHg, and median (range) Eckardt score was 7 (4-10). Nine patients were treated by pneumatic dilatation and seven by myotomy. Nine patients underwent three-dimensional high-resolution esophageal manometry after treatment. Before treatment, the esophagogastric junction pressure distribution was best observed at end expiration and during the 4 s of the integrated relaxation pressure measurement. During the integrated relaxation pressure, the lower esophageal sphincter was asymmetric in 12 patients with a high-pressure zone between the left and the posterior side of the esophagogastric junction. After treatment, five patients had a residual high-pressure point on the left or the posterior side of the esophagogastric junction.

CONCLUSIONS

Three-dimensional high-resolution esophageal manometry allows a simple assessment of the pressure topography at the EGJ. In patients with achalasia, we found the esophagogastric junction pressure to be asymmetric with a peak pressure on the greater curvature side. Three-dimensional high-resolution esophageal manometry has the potential to guide initial and redo treatments.

Using Impedance Planimetry (EndoFLIP) to Evaluate Myotomy and Predict Outcomes After Surgery for Achalasia

BACKGROUND

The functional lumen imaging probe (FLIP) is an innovative tool that uses impedance planimetry to assess esophageal geometry in real time. It has been used to diagnose achalasia and evaluate treatment failure after laparoscopic Heller myotomy (LHM) and peroral endoscopic myotomy (POEM). We hypothesize that impedance planimetry can be utilized intra-operatively to assess adequacy of myotomy and assist in predicting patient outcomes.

METHODS

A prospectively maintained patient database at a single center was queried. Seventy-seven patients with achalasia underwent POEM or LHM by a single surgeon. The FLIP was used to measure cross-sectional area (CSA), minimum diameter (D_min), balloon pressure, and distensibility index (DI) of the lower esophageal sphincter (LES) before and after the procedure. Clinical outcomes were measured up to 2 years after treatment.

RESULTS

Post-operative CSA, D_min, balloon pressure, and DI values were significantly different from pre-operative values (p < 0.001). Patients with a post-operative Eckardt score ≥ 3 were significantly more likely to have a final DI ≤ 3.1 mm²/mmHg (p = 0.014) or a change in DI ≤ 3.0 mm²/mmHg (p = 0.010). Additionally, a final CSA > 96 mm² or D_min > 11.0 mm was predictive of worse reflux at 2 years (p = 0.01).

CONCLUSION

Impedance planimetry using the FLIP can offer intra-operative feedback about the geometry of the LES. The most useful parameters in predicting patient outcomes have yet to be clearly defined, but our results demonstrate that final DI and CSA are predictive of post-operative treatment response.

Epiphrenic diverticula: An added source of complexity in achalasia management

Epiphrenic (pulsion) esophageal diverticula can occur in the setting of underlying esophageal motility disorders such as achalasia and present a unique management challenge to the gastroenterologist. Asymptomatic diverticula do not require treatment, but symptomatic diverticula require therapy targeted to the underlying esophageal motility disorder, or else the diverticula will recur. Generally, laparoscopic or combined laparoscopic/thoracoscopic myotomy, diverticulectomy, and anterior fundoplication are required. However, therapeutic options for epiphrenic diverticula are evolving as peroral endoscopic myotomy (POEM) becomes more commonplace. We review two cases of achalasia complicated by epiphrenic diverticula at our institution. In the first case, type II achalasia was identified and the patient underwent laparoscopic myotomy. In the second case, type III achalasia was present and the patient underwent successful POEM. We discuss the presentation, pathophysiology, and management of epiphrenic diverticula as well as the expanding role for POEM in diverticula.

Use of Impedance Planimetry (Endoflip) in Foregut Surgery Practice: Experience of More than 400 Cases

BACKGROUND

We provide a comprehensive report of our institution's experience with the endoluminal functional lumen imaging probe (Endoflip) impedance planimetry system, a device that can be used intraoperatively to objectively evaluate the distensibility of any sphincter of the gastrointestinal tract. We aim to describe the variety of ways in which the Endoflip can be used in a foregut surgeon's practice.

STUDY DESIGN

This is a retrospective review of a prospectively maintained quality database of all patients in which the functional lumen imaging probe (FLIP) system was used between February 2013 and June 2019.

RESULTS

During the study period, 402 FLIP cases were performed: 226 fundoplications, 94 peroral endoscopic myotomies, 15 peroral pyloromyotomies, 12 antireflux mucosectomies, 11 magnetic sphincter augmentations, 9 laparoscopic Heller myotomies, 8 pre-esophagectomy esophagogastroduodenoscopies (EGDs), 4 diagnostic EGDs, 8 endoscopic Zenker's diverticulotomies, 5 post-peroral endoscopic myotomy EGDs, 8 EGDs with dilations, and 2 transoral incisional fundoplications.

CONCLUSIONS

Within a foregut surgeon's practice, the FLIP can be used to measure the upper esophageal sphincter, lower esophageal sphincter, and pylorus in a variety of clinical scenarios and settings.

Functional lumen imaging probe in gastrointestinal motility diseases

Dysfunction of gastrointestinal (GI) sphincters, including the lower esophageal sphincter (LES) at the esophagogastric junction (EGJ) and the pyloric sphincter, plays a vital role in GI motility disorders, such as achalasia, gastroesophageal reflux disease (GERD), gastroparesis, and fecal incontinence. Using multi-detector high-resolution impedance planimetry, the functional luminal imaging probe (FLIP) system measures simultaneous data on tissue distensibility and luminal geometry changes in the sphincter in a real-time manner. In this review we focus on the emerging data on FLIP, which can be used as an innovative diagnostic method during endoscopic or surgical procedures in GI motility disorders. Subsequent large, prospective, standardizing studies are needed to validate these findings before it can be put to routine clinical use.

Difficult peroral endoscopic myotomy: definition and management strategies

Introduction: Peroral endoscopic myotomy (POEM) has been established as an alternative endoscopic method for the treatment of achalasia, and several studies have confirmed its relatively long-term efficacy. Although most of the POEM procedures can be smoothly completed, technical difficulties do arise during the treatment of some patients, which may lead to prolonged procedure duration, increased procedure-related complications, or even aborted POEM.Area covered: In the present review, we provide a comprehensive review of difficult POEM, focusing on its definition, risk factors, and intraoperative management strategies. The present review is expected to provide tips for not so experienced operators who perform POEM.Expert commentary: Submucosal fibrosis and sigmoid-type esophagus are associated with difficult POEM. Sometimes, the following may also be associated with difficult POEM: previous endoscopic or surgical treatments, spastic esophageal disorders (type III achalasia, distal esophageal spasm, and hypercontractile esophagus), achalasia with diverticulum or situs inversus. For operators who begin to perform POEM, I suggest an exclusion of patients with severe submucosal fibrosis or sigmoid-type esophagus, and begin to perform POEM for these patients when they have completed at least 50 cases of 'easy POEM' and the proposed management strategies may be helpful.

Intraoperative assessment of esophageal motility using FLIP during myotomy for achalasia

BACKGROUND

The functional luminal imaging probe (FLIP) can evaluate esophagogastric junction (EGJ) distensibility and esophageal peristalsis in real time. FLIP measurements performed during diagnostic endoscopy can accurately discriminate between healthy controls and patients with achalasia based on EGJ-distensibility and distinct motility patterns termed repetitive antegrade contractions (RACs) and repetitive retrograde contractions (RRCs). We sought to evaluate real-time motility changes in patients undergoing surgical myotomy for achalasia.

METHODS

FLIP measurements using a stepwise volumetric distention protocol were performed at three time points during assessment and performance of laparoscopic Heller myotomy and POEM: (1) During preoperative outpatient endoscopy, (2) Intraoperatively following induction of anesthesia, and (3) Intraoperatively after myotomy completion. EGJ-distensibility, contractility, RACs, and RRCs were measured.

RESULTS

FLIP measurements were performed in 32 patients. The EGJ-distensibility index was similar between the preoperative and initial operative measurements (1.1 vs 1.4 mm²/mmHg, p = NS). There was a significant increase in distensibility following surgical myotomy (1.4 to 4.7 mm²/mmHg, p < 0.01). Intraoperative contractile patterns varied between achalasia subtypes. Contractility was seen in < 20% of assessments in patients with types I and II achalasia. Type III patients demonstrated contractility in 100% of assessments, with 70% exhibiting RRCs and 60% RACs. There was a reduction in the frequency of RRC presence (70% to 20%), and contractile vigor (80% to 0% of patients with lumen occluding contractions) in type III patients following surgical myotomy.

CONCLUSIONS

This first report of real-time intraoperative measurement of esophageal motility using FLIP demonstrates the feasibility of such assessments during surgical myotomy for achalasia. Patients with type I and II achalasia exhibited rare intraoperative contractility, while the presence of motility was the norm in those with type III. Patients with type III achalasia demonstrated an immediate reduction in repetitive contraction motility patterns and contractile vigor following myotomy.

Bridging the Gap between Advancements in the Evolution of Diagnosis and Treatment towards Better Outcomes in Achalasia

Over the past few decades, there was an encouraging breakthrough in bridging the gap between advancements in the evolution of diagnosis and treatment towards a better outcome in achalasia. The purpose of this review is to provide updated knowledge on how the current evidence has bridged the gap between advancements in the evolution of diagnosis and treatment of esophageal achalasia. The advent of high-resolution manometry and standardization based on the Chicago classification has increased early recognition of the disease. These 3 clinical subtypes of achalasia can predict the outcomes of patients, and the introduction of POEM has revolutionized the choice of treatment. Previous evidence has shown that laparoscopic Heller myotomy (LHM) and anterior fundoplication were considered the most durable treatments for achalasia. Based on the current evidence, POEM has been evolving as a promising strategy and is effective against all 3 types of achalasia, but the efficacy of POEM is based on short- and medium-term outcome studies from a limited number of centers. Types I and II achalasia respond well to POEM, LHM, and PD, while most studies have shown that type III achalasia responds better to POEM than to LHM and PD. In general, among the 3 subtypes of achalasia, type II achalasia has the most favorable outcomes after medical or surgical therapies. The long-term efficacy of POEM is still unknown. The novel ENDOFLIP measures the changes in intraoperative esophagogastric junction dispensability, which enables a quantitative assessment of luminal patency and sphincter distension; however, this technology is in its infancy with little data to date supporting its intraoperative use. In the future, identifying immunomodulatory drugs and the advent of stem cell therapeutic treatments, including theoretically transplanting neuronal stem cells, may achieve a functional cure. In summary, it is important to identify the clinical subtype of achalasia to initiate target therapy for these patients.

Exploring pyloric dynamics in stenting using a distensibility technique

BACKGROUND

Perforated duodenal ulcers can be treated with a covered stent. Stent migration is a severe complication, sometimes requiring surgery. Pyloric physiology during stent treatment has not been studied and mechanisms for migration are unknown. The aim of this study was to investigate the pyloric response to distention, mimicking stent treatment, using the EndoFLIP.

METHODS

A nonsurvival study in five pigs was carried out, followed by a pilot study in one volunteer. Animals were gastroscoped during anaesthesia and the EndoFLIP was placed straddling the pylorus. Baseline distensibility readings were performed at stepwise balloon distentions to 20, 30, 40, and 50 mL, measuring pyloric cross-sectional area and pressure. Measurements were repeated after administration of a prokinetic drug and after a liquid meal. In the human study, readings were performed in conscious sedation at baseline and after stimulation with metoclopramide.

KEY RESULTS

During baseline readings, the pylorus was shown to open more with increasing distention together with higher amplitude motility waves. Reaching maximum distention-volume (50 mL), pyloric pressure increased significantly (P = 0.016), and motility waves disappeared. After prokinetic stimulation, the pressure decreased and the motility waves increased in frequency and amplitude. After food stimulation, the pressure stayed low and the motility showed increase in amplitude. During both tests, the pylorus showed higher pressure and lack of motility waves at maximum probe distention.

CONCLUSIONS AND INFERENCES

The pylorus seems to act as a sphincter at low distention but when further dilated starts acting as a pump. Fully distended the pyloric motility disappears and the pressure remains high, suggesting that a stent with high-radial force might show less migration.

Management of achalasia cardia: Expert consensus statements

Achalasia cardia (AC) is a frequently encountered motility disorder of the esophagus resulting from an irreversible degeneration of neurons. Treatment modalities are palliative in nature, and there is no curative treatment available for AC as of now. Significant advancements have been made in the management of AC over last decade. The introduction of high resolution manometry and per-oral endoscopic myotomy (POEM) has strengthened the diagnostic and therapeutic armamentarium of AC. High resolution manometry allows for the characterization of the type of achalasia, which in turn has important therapeutic implications. The endoscopic management of AC has been reinforced with the introduction of POEM that has been found to be highly effective and safe in palliating the symptoms in short-term to mid-term follow-up studies. POEM is less invasive than Heller's myotomy and provides the endoscopist with the opportunity of adjusting the length and orientation of esophageal myotomy according to the type of AC. The management of achalasia needs to be tailored for each patient, and the role of pneumatic balloon dilatation, POEM, or Heller's myotomy needs to be revisited. In this review, we discuss the important aspects of diagnosis as well as management of AC. The statements presented in the manuscript reflect the cumulative efforts of an expert consensus group.

What Is the Future of Impedance Planimetry in Gastroenterology?

The gastrointestinal (GI) tract is efficient in transporting ingested material to the site of delivery in healthy subjects. A fine balance exists between peristaltic forces, the mixing and delivery of the contents, and sensory signaling. This fine balance is easily disturbed by diseases. It is mandatory to understand the pathophysiology to enhance our understanding of GI disorders. The inaccessibility and complex nervous innervation, geometry and mechanical function of the GI tract make mechanosensory evaluation difficult. Impedance planimetry is a distension technology that assesses luminal geometry, mechanical properties including muscle dynamics, and processing of nociceptive signals from the GI tract. Since standardized models do not exist for GI muscle function in vivo, models, concepts, and terminology must be borrowed from other medical fields such as cardiac mechanophysiology. The review highlights the impedance planimetric technology, muscle dynamics assessment, and 3 applied technologies of impedance planimetry. These technologies are the multimodal probes that assesses sensory function, the functional luminal imaging probe that dynamically measures the geometry of the lumen it distends, and Fecobionics that is a simulated feces providing high-resolution measurements during defecation. The advanced muscle analysis and 3 applied technologies can enhance the quality of future interdisciplinary research for gaining more knowledge about mechanical function, sensory-motor disorders, and symptoms. This is a step in the direction of individualized treatment for GI disorders based on diagnostic subtyping. There seems to be no better alternatives to impedance planimetry, but only the functional luminal imaging probe is currently commercially available. Wider use depends on commercialization of the multimodal probe and Fecobionics.

Systematic Review and Meta-Analysis of Perioperative Outcomes of Peroral Endoscopic Myotomy (POEM) and Laparoscopic Heller Myotomy (LHM) for Achalasia

AIMS AND OBJECTIVES

Laparoscopic Heller myotomy (LHM) is the preferred surgical method for treating achalasia. However, peroral endoscopic myotomy (POEM) is providing good short-term results. The objective of this systematic review and meta-analysis was to compare the safety and efficacy of LHM and POEM.

MATERIALS AND METHODS

A search of PubMed, Cochrane database, Medline, Embase, Science Citation Index, and current contents for English-language articles comparing LHM and POEM between 2007 and 2016 was performed. Variables analyzed included prior endoscopic treatment, prior medical treatment, prior Heller myotomy, operative time, overall complications rate, postoperative gastroesophageal reflux disease (GERD), length of hospital stay, postoperative pain score, and long-term GERD.

RESULTS

Seven trials consisting of 483 (LHM=250, POEM=233) patients were analyzed. Preoperative variables, for example, prior endoscopic treatment [odds ratio (OR), 1.32; 95% confidence interval (CI), 0.23-4.61; P=0.96], prior medical treatment [weighted mean difference (WMD), 1.22; 95% CI, 0.52-2.88; P=0.65], and prior Heller myotomy (WMD, 0.47; 95% CI, 0.13-1.67; P=0.25) were comparable. Operative time was 26.28 minutes, nonsignificantly longer for LHM (WMD, 26.28; 95% CI, -11.20 to 63.70; P=0.17). There was a comparable overall complication rate (OR, 1.25; 95% CI, 0.56-2.77; P=0.59), postoperative GERD rate (OR, 1.27; 95% CI, 0.70-2.30; P=0.44), length of hospital stay (WMD, 0.30; 95% CI, -0.24 to 0.85; P=0.28), postoperative pain score (WMD, -0.26; 95% CI, -1.58 to 1.06; P=0.70), and long-term GERD (WMD, 1.06; 95% CI, 0.27-4.1; P=0.08) for both procedures. There was a significantly higher short-term clinical treatment failure rate for LHM (OR, 9.82; 95% CI, 2.06-46.80; P<0.01).

CONCLUSIONS

POEM compares favorably to LHM for achalasia treatment in short-term perioperative outcomes. However, there was a significantly higher clinical treatment failure rate for LHM on short-term postoperative follow-up. Presently long-term postoperative follow-up data for POEM beyond 1 year are unavailable and eagerly awaited.

An Update on Current Management Strategies for Achalasia and Future Perspectives

The last decade has seen growing insight into the pathophysiology of achalasia, and current treatments decreasing the resting pressure in the lower esophageal sphincter by endoscopic (botulinum toxin injection, pneumatic dilation, peroral endoscopic myotomy) or surgical means (Heller myotomy). Manometry is considered the gold standard to confirm the diagnosis of achalasia. Pneumatic dilation and laparoscopic Heller myotomy have similar effectiveness and are both more successful in patients with type II achalasia. Laparoscopic myotomy when combined with partial fundoplication is an effective surgical technique and has been considered the operative procedure of choice until recently. Peroral endoscopic myotomy is an emerging therapy with promising results since it offers a minimally invasive and efficacious option especially in type III achalasia. However, it remains to be determined if peroral endoscopic myotomy offers long-term efficacy.

[Surgical treatment of achalasia - endoscopic or laparoscopic? : Proposal for a tailored approach]

Primary idiopathic achalasia is the most common form of the rare esophageal motility disorders. A curative therapy which restores the normal motility does not exist; however, the therapeutic principle of cardiomyotomy according to Ernst Heller leads to excellent symptom control in the majority of cases. The established standard approach is Heller myotomy through the laparoscopic route (LHM), combined with Dor anterior fundoplication for reflux prophylaxis/therapy. At least four meta-analyses of randomized controlled trials (RCTs) have demonstrated superiority of LHM over pneumatic dilation (PD); therefore, LHM should be used as first line therapy (without prior PD) in all operable patients. Peroral endoscopic myotomy (POEM) is a new alternative approach, which enables Heller myotomy to be performed though the endoscopic submucosal route. The POEM procedure has a low complication rate and also leads to good control of dysphagia but reflux rates can possibly be slightly higher (20-30%). Long-term results of POEM are still scarce and the results of the prospective randomized multicenter trial POEM vs. LHM are not yet available; however, POEM seems to be the preferred treatment option for certain indications. Within the framework of the tailored approach for achalasia management of POEM vs. LHM established in Würzburg, we recommend long-segment POEM for patients with type III achalasia (spasmodic) and other hypercontractile motility disorders and potentially type II achalasia (panesophageal compression) with chest pain as the lead symptom, whereas LHM can also be selected for type I. For sigmoid achalasia, especially with siphon-like transformation of the esophagogastric junction, simultaneous hiatal hernia and epiphrenic diverticula, LHM is still the preferred approach. The choice of the procedure for revisional surgery in case of recurrent dysphagia depends on the suspected mechanism (morphological vs. functional/neuromotor).

Editorial: Assessing Esophageal Function in Achalasia: The Old and the New

Achalasia is currently diagnosed according to the Chicago Classification v3.0 using high-resolution manometry and treatment focuses on disruption of the esophagogastric junction. A paper in this issue examines the utility of a timed barium esophagram with a 13 mm tablet challenge in differentiating achalasia from other diagnoses, finding 100% sensitivity. However, a large proportion of patients with non-achalasia dysphagia are also identified. Another paper in this issue proposes utilizing intraprocedure functional luminal imaging probe measurement during pneumatic dilation as a guide for upsizing dilations. This appears promising, but prospective validation is necessary before this becomes standard of care.

Achalasia: It Is Not All Black and White

PURPOSE OF REVIEW

This review aims to shed light on subtleties of achalasia diagnosis, including potential pitfalls that may lead to errors. Optimal methods for assessment of disease severity and the relationship between achalasia and other motility disorders will also be reviewed with an emphasis on recent findings from the literature.

RECENT FINDINGS

Adjunctive testing with viscous substances or larger water volumes should be used routinely as it improves the accuracy of achalasia diagnosis. Chronic opiate use can mimic achalasia. The timed barium swallow remains the best test for assessments of disease severity and prognostication, but the functional lumen-imaging probe, a newer tool which measures esophagogastric junction distensibility using impedance planimetry, is emerging as a potentially more powerful tool for these purposes. Functional esophagogastric junction outflow obstruction is possibly part of the achalasia spectrum. By addressing the potential pitfalls described, and through routine and standardized use of the diagnostic tools mentioned herein, the accuracy of diagnosis, severity assessment, and prognostication of achalasia can be improved.

Consistency and effect of body position change on measurement of upper and lower esophageal sphincter geometry using impedance planimetry in a canine model

The EndoFLIP (Endolumenal Functional Lumen Imaging Probe, Crospon Inc, Galway, Ireland) device uses the technique of impedance planimetry to evaluate dimensions and distensibility of the upper and lower esophageal sphincter. The null hypotheses for this study were that EndoFLIP variables would be stable between anesthestic episodes and would not be affected by body position when evaluating the upper and lower esophageal sphincters in healthy dogs. During each of three consecutive general anesthesia episodes administered to eight healthy adult research colony dogs with a standardized protocol, the EndoFLIP catheter was positioned to measure cross-sectional area, intrabag pressure, upper and lower esophageal sphincter length at two different balloon fill volumes (30 and 40 mL) and two body positions (lateral and dorsal recumbency). From these measured variables, a distensibility index was also calculated. Mixed effect analysis of variance was used to evaluate the fixed marginal and interaction effects of anesthesia episode, body position, and balloon volume on measured and calculated variables. For the upper esophageal sphincter significant interactions were present between anesthetic episode and body position for all variables except intrabag pressure; adjusting for body position significant differences were present between anesthetic episodes for all variables except distensibility index; adjusting for anesthetic episode cross-sectional area, intrabag pressure, upper esophageal sphincter length and distensibility index were all affected by body position. For the lower esophageal sphincter distensibility index was the only variable where a significant interaction between anesthesia episode and body position occurred; cross-sectional area, intrabag pressure, and lower esophageal length were not significantly affected by anesthesia episode when adjusting for body position; distensibility index was the only variable significantly affected by body position. Measurements of the geometry of the lower esophageal sphincter as measured by the EndoFLIP device were consistent under conditions of general anesthesia. Similar measurements taken at the upper esophageal sphincter displayed greater variability between anesthetic episodes and were affected to a greater extent by body position. Body position should be standardized in studies using the EndoFLIP to assess geometric and functional characteristics of the upper and lower esophageal sphincters.

Application of the Functional Lumen Imaging Probe to Esophageal Disorders

OPINION STATEMENT

The functional luminal imaging probe (FLIP) provides a novel method to evaluate esophageal physiology and function in both health and disease. FLIP enables assessment of a previously underexplored component of esophageal function, distensibility, by utilizing high-resolution impedance planimetry to evaluate the relationship of the esophageal luminal geometry with pressure during controlled volumetric distension. Recent studies have described the potential utility of FLIP to evaluate the severity and effectiveness of therapy for esophageal diseases including achalasia, gastroesophageal reflux disease, and eosinophilic esophagitis. This review summarizes these emerging clinical applications of FLIP in the evaluation and management of esophageal diseases.

Functional Lumen Imaging Probe for the Management of Esophageal Disorders: Expert Review From the Clinical Practice Updates Committee of the AGA Institute

The functional luminal imaging probe is a Food and Drug Administration-approved measurement tool used to measure simultaneous pressure and diameter to guide management of various upper gastrointestinal disorders. Additionally, this tool is also approved to guide therapy during bariatric procedures and specialized esophageal surgery. Although it has been commercially available since 2009 as the endolumenal functional lumen imaging probe (EndoFLIP), the functional luminal imaging probe has had limited penetrance into clinical settings outside of specialized centers. This is primarily because of a paucity of data supporting its utility in general practice and a lack of standardized protocols and data analysis methodology. However, data are accumulating that are providing guidance regarding emerging applications in the evaluation and management of foregut disorders. This clinical practice update describes the technique and reviews potential indications in achalasia, eosinophilic esophagitis, and gastroesophgeal reflux disease. Best Practice Advice 1: Clinicians should not make a diagnosis or treatment decision based on functional lumen imaging probe (FLIP) assessment alone. Best Practice Advice 2: FLIP assessment is a complementary tool to assess esophagogastric junction opening dynamics and the stiffness of the esophageal wall. Best Practice Advice 3: Utilization should follow distinct protocols and analysis paradigms based on the disease state of interest. Best Practice Advice 4: Clinicians should not utilize FLIP in routine diagnostic assessments of gastroesophageal reflux disease. Best Practice Advice 5: FLIP should not be used to diagnose eosinophilic esophagitis but may have a role in severity assessment and therapeutic monitoring.