Outcomes after per-oral endoscopic myotomy for Zenker's diverticula (Z-POEM) and correlation with impedance planimetry (FLIP).

INTRODUCTION: Zenker's diverticulum (ZD) is a false pulsion diverticulum of the cervical esophagus. It is typically found in older adults and manifests with dysphagia. The purpose of this study is to describe our experience with Per-oral endoscopic myotomy for Zenker's (Z-POEM) and intraoperative impedance planimetry (FLIP). METHODS: We performed a single institution retrospective review of patients undergoing Z-POEM in a prospective database between 2014 and 2022. Upper esophageal sphincter (UES) distensibility index (DI, mm2/mmHg) was measured by FLIP before and after myotomy. The primary outcome was clinical success. Secondary outcomes included technical failure, adverse events, and quality of life as assessed by the gastroesophageal health-related quality of life (GERD-HRQL), reflux severity index (RSI), and dysphagia score. A statistical analysis of DI was done with the paired t-test (p < 0.05). RESULTS: Fifty-four patients underwent Z-POEM, with FLIP measurements available in 30 cases. We achieved technical success and clinical success in 54/54 (100%) patients and 46/54 patients (85%), respectively. Three patients (6%) experienced contained leaks. Three patients were readmitted: one for aforementioned contained leak, one for dysphagia, and one post-operative pneumonia. Three patients with residual dysphagia underwent additional endoscopic procedures, all of whom had diverticula > 4 cm. Following myotomy, mean DI increased by 2.0 ± 1.7 mm2/mmHg (p < 0.001). In those with good clinical success, change in DI averaged + 1.6 ± 1.1 mm2/mmHg. Significant improvement was found in RSI and GERD-HRQL scores, but not dysphagia score. CONCLUSION: Z-POEM is a safe and feasible for treatment of ZD. We saw zero cases of intraoperative abandonment. We propose that large diverticula (> 4 cm) are a risk factor for poor outcomes and may require additional endoscopic procedures. An improvement in DI is expected after myotomy, however, the ideal range is still not known.

Endoscopic impedance planimetry versus high-resolution manometry (HRM) for pre-operative motility evaluation in anti-reflux surgery.

INTRODUCTION: Pre-operative evaluation of patients with gastroesophageal reflux disease (GERD) includes assessment of esophageal motility. High-resolution manometry (HRM) is the gold standard; endoscopic impedance planimetry (IP) with Endoflip 2.0 is increasingly utilized in esophageal disorders of motility. We hypothesized that normal IP motility would correlate with normal HRM motility and tested this in a prospective cohort study. METHODS: Patients presenting for surgical evaluation of GERD between 9/2020 and 10/2021 were prospectively enrolled under an IRB-approved protocol. Patients with prior esophageal/gastric surgery, known motility disorders, or large paraesophageal hernias were excluded. All underwent HRM and IP, with normal motility defined by Chicago 3.0 classification for HRM and the presence of repetitive antegrade contractions for IP. Logistic regression and t test were used to analyze the data; p value < 0.05 was considered significant. RESULTS: Of 63 patients enrolled, 48 completed both IP and HRM testing. The cohort was 50% male with a median age of 52.5 [42.0, 66.0] years, mostly ASA class 1-2 (75.1%, n = 36) and had an average BMI of 31.4 ± 6.3 kg/m2. Normal motility tracings were in 62.5% of IP and 75% of HRM tests. Using HRM as the gold standard, IP detected normal motility with a sensitivity of 65.8% and a specificity of 50% (positive predictive value 83.3%, negative predictive value 27.8%). Normal IP was not statistically significant in predicting normal HRM (OR 3.182, 95% CI 0.826-12.262, p = 0.0926). Tolerability of IP was significantly better than HRM with lower rates of discomfort (10.9% vs. 93.4%, p < 0.0001) and higher willingness to repeat testing (100% vs. 47.8%, p < 0.0001). CONCLUSION: Esophageal motility testing with Endoflip 2.0 is well tolerated by patients. The low specificity (50%), poor negative predictive value (27.8%), and lack of statistically significant concordance between IP and HRM raises concern for the reliability of this test as a stand-alone replacement for HRM in the pre-operative evaluation for GERD.

Impedance planimetry during per-oral endoscopic myotomy is associated with decreased inadvertent capnoperitoneum.

BACKGROUND: Per-oral endoscopic myotomy (POEM) has become an accepted minimally invasive alternative to Heller myotomy for the treatment of achalasia and other disorders of esophageal dysmotility. One associated adverse event is the inadvertent creation of capnoperitoneum. A proposed mechanism is that extension of the submucosal tunnel below the esophageal hiatus and onto the gastric wall leads to transmural perforation. We hypothesized that the use of impedance planimetry with the endoscopic functional luminal imaging probe (EndoFLIP) more accurately identifies the esophagogastric junction and helps to better define the myotomy's ideal limits, thus lowering the incidence of inadvertent capnoperitoneum. METHODS: This is a single-center, retrospective review of consecutive POEM cases from 06/11/2011 to 08/08/2022, with EndoFLIP introduced in 2017. Patient and procedural characteristics, including the incidence of clinically significant capnoperitoneum and decompression, were analyzed using univariate and multivariable linear regression statistics. RESULTS: There were 140 POEM cases identified, 74 (52.9%) of which used EndoFLIP. Clinically significant capnoperitoneum was encountered in 26 (18.6%) cases, with no differences in patient characteristics between those who had capnoperitoneum and those who did not. There was a decreased incidence of capnoperitoneum in cases using EndoFLIP compared to those without (n = 6, 23% vs n = 20, 77%, p = 0.001), with zero instances in the final 56 cases. After adjusting for potentially confounding factors, EndoFLIP use was associated with a - 15.93% (95% confidence interval - 30.68%, - 1.18%) decrease in procedure duration. CONCLUSIONS: The routine use of EndoFLIP during POEM was associated with decreased incidence of clinically significant capnoperitoneum, potentially due to improved myotomy tailoring and decreased duration of insufflation with shorter procedure times.

The effect of per-oral endoscopic myotomy by achalasia subtype as measured by impedance planimetry.

BACKGROUND: Achalasia is an esophageal motility disorder with three subtypes based on manometry that can treated with per-oral endoscopic myotomy (POEM). With the advent of impedance planimetry (EndoFLIP®), we hypothesized the three achalasia subtypes would have different pre-POEM EndoFLIP® diameter and distensibility index (DI) measurements but would be similar after POEM. METHODS: A single-institution, retrospective review of consecutive POEM cases by a single surgeon-endoscopist team from 04/07/2017 to 08/28/2023. Patients with a diagnosis of achalasia were stratified into type 1, 2, or 3 based on pre-POEM manometry. Patient characteristics, Eckardt scores, and pre-and-post-POEM diameter and DI were compared by subtype with descriptive, univariate, and multivariable linear regression statistics. RESULTS: Sixty-four patients met inclusion criteria, of whom 9(14.1%) had Type 1, 36(56.3%) had Type 2, and 19(29.7%) had Type 3. There were no differences between Types with respect to median pre-POEM Eckardt scores (9[IQR:7-9) vs. 8[IQR:6-9] vs. 7[IQR:5-8], p = 0.148), median post-POEM Eckardt scores (0[IQR:0-1] vs. 0[IQR:0-0] vs. 0[IQR0-0.5], p = 0.112). EndoFLIP® data revealed variation in median pre-POEM diameter and DI between Subtypes (6.9[IQR:6-8.5] vs. 5.5[IQR:5-6.8] vs. 5[IQR:5-6.1], p = 0.025 and 1.8[IQR:1.3-3.2] vs. 0.9[IQR:0.6-1.6] vs. 0.6[IQR:0.5-0.8], p = 0.003, respectively), but not in the change in diameter or DI post-POEM (5.1[IQR:4.3-5.9] vs. 5.1[IQR:4.1-7.1] vs. 5.9[IQR:5-6.4], p = 0.217 and 3.9[IQR:2.5-4.7] vs. 3.4[IQR:2.4-4.7] vs. 2.7[IQR:2.3-3.7], p = 0.461, respectively). However, after adjusting for potentially confounding factors, pre- or post-POEM diameter and DI did not demonstrate statistically significant differences among subtypes. CONCLUSIONS: Achalasia subtypes did not demonstrate different pre-POEM diameters or DI as measured by EndoFLIP® nor are there differences after POEM completion. While achalasia subtypes may have slightly different pathophysiology based on manometry findings, similar pre- and post-POEM impedance planimetry findings, along with similar Eckardt scores, support the use of POEM in the treatment of any achalasia subtype.

Impedance planimetry (EndoFLIPTM) and surgical outcomes after Hill compared to Toupet fundoplication.

INTRODUCTION: Endoluminal functional lumen imaging probe (EndoFLIP) provides a real-time assessment of gastroesophageal junction (GEJ) compliance during fundoplication. Given the limited data on EndoFLIP measurements during the Hill procedure, we investigated the impact of the Hill procedure on GEJ compliance compared to Toupet fundoplication. METHODS: Patients who underwent robotic Hill or Toupet fundoplication with intraoperative EndoFLIP between 2017 and 2022 were included. EndoFLIP measurements of the GEJ included cross sectional surface area (CSA), intra-balloon pressure, high pressure zone length (HPZ), distensibility index (DI), and compliance. Subjective reflux symptoms, gastroesophageal reflux disease-health related quality of life (GERD-HRQL) score, and dysphagia score were assessed pre-operatively as well as at short- and longer-term follow-up. RESULTS: One-hundred and fifty-four patients (71.9%) had a Toupet fundoplication while sixty (28%) patients underwent the Hill procedure. The CSA [27.7 ± 10.9 mm2 vs 42.2 ± 17.8 mm2, p < 0.0001], pressure [29.5 ± 6.2 mmHg vs 33.9 ± 8.5 mmHg, p = 0.0009], DI [0.9 ± 0.4 mm2/mmHg vs 1.3 ± 0.6 mm2/mmHg, p = 0.001], and compliance [25.9 ± 12.8 mm3/mmHg vs 35.4 ± 13.4 mm3/mmHg, p = 0.01] were lower after the Hill procedure compared to Toupet. However, there was no difference in post-fundoplication HPZ between procedures [Hill: 2.9 ± 0.4 cm, Toupet: 3.1 ± 0.6 cm, p = 0.15]. Follow-up showed no significant differences in GERD-HRQL scores, overall dysphagia scores or atypical symptoms between groups (p > 0.05). CONCLUSION: The Hill procedure is as effective to the Toupet fundoplication in surgically treating gastroesophageal reflux disease (GERD) despite the lower CSA, DI, and compliance after the Hill procedure. Both procedures led to DI < 2 mm2/mmHg with no significant differences in dysphagia reporting (12-24) months after the procedure. Further studies to elucidate a cutoff value for DI for postoperative dysphagia development are still warranted.

Using impedance planimetry to define the end of a peroral endoscopic myotomy.

INTRODUCTION: Peroral endoscopic myotomy (POEM) is a minimally invasive endoscopic option for management of achalasia. Adequate distal myotomy is necessary for relief of symptoms, but when too long may also increase risk of reflux. The objective of this study is to evaluate clinical outcomes after POEM and final length of gastric myotomy using impedance planimetry (EndoFLIP). METHODS: A retrospective review of 34 consecutive patients undergoing POEM with EndoFLIP were included. EndoFLIP measurements, including esophagogastric junction distensibility index (DI), minimum diameter (Dmin), and cross-sectional area (CSA) were recorded at 30- and 40-mL balloon-fill pre- and post- myotomy. The myotomy was considered complete when DI ≥ 3.4 mm2/mmHg. Postoperative Eckardt score (ES) was determined at initial postoperative visit and most recent follow-up. Linear and logistic regression were used to evaluate the association between gastric myotomy length and post-myotomy EndoFLIP measurements on postoperative ES and GERD. Wilcoxon rank-sum test was used to compare gastric myotomy lengths and EndoFLIP parameters in relation to clinical success and development of GERD, and paired t-test to compare EndoFLIP measurements and ES pre- and post-myotomy. RESULTS: Final length of gastric myotomy measured 1 cm in 1 (2.9%), 1.5 cm in 11 (32.4%), 2.0 cm in 19 (55.9%), and 2.5 cm in 3 (8.8%) patients. Mean preoperative ES was 6.6 ± 2.2. All patients achieved ES < 3 postoperatively, which was maintained in 88.5% of patients at a median of 7.5 months of follow-up. Gastric myotomy length and post-myotomy EndoFLIP values were not associated with postoperative Eckardt scores or GERD. DISCUSSION: Early and late symptom relief was achieved in 100 and 88.5% of patients, respectively, at a gastric myotomy length of 1-2.5 cm. Using EndoFLIP to define a completed myotomy at DI of 3.4 mm2/mmHg yielded variable lengths of gastric myotomy.

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.

Tailoring the wrap: intraoperative functional lumen imaging probe (FLIP) during hiatal hernia repair.

INTRODUCTION: The introduction of the functional lumen imaging probe (FLIP) has provided objective, real-time feedback on the geometric variations with each component of a hiatal hernia repair (HHR). The utility of this technology in altering intraoperative decision-making has been scarcely reported. Herein, we report a single-center series of intraoperative FLIP during HHR. METHODS: A retrospective review of electronic medical records between 2020 and 2022 was conducted and all patients undergoing non-recurrent HHR with FLIP were queried. Patient and hernia characteristics, intraoperative FLIP values and changes in decision-making, as well as early post-operative outcomes were reported. Both diameter and distensibility index (DI) were measured at 40 ml and 50 ml balloon inflation after hiatal dissection, after hiatal closure, and after fundoplication when indicated. RESULTS: Thirty-three patients met inclusion criteria. Mean age was 62 ± 14 years and mean BMI was 28 ± 6 kg/m2. The majority (53%) were type I hiatal hernias. The largest drop in DI occurred after hiatal closure, with minimal change seen after fundoplication (mean DI of 4.3 ± 2. after completion of HH dissection, vs 2.7 ± 1.2 after hiatal closure and 2.3 ± 1 after fundoplication when performed). In 13 (39%) of cases, FLIP values directly impacted intraoperative decision-making. Fundoplication was deferred in 4/13 (31%) patients, the wrap was loosened in 2/13 (15%); the type of fundoplication was altered to achieve adequate anti-reflux values in 2/13 (15%) patients, and in 1/13 (3%) the wrap was tightened. CONCLUSION: FLIP measurements can be used intraoperatively to guide decision-making and alter management plan based on objective values. Long-term outcomes and further prospective studies are required to better delineate the value of this technology.

Esophagogastric junction compliance on impedance planimetry (EndoFLIP™) following peroral endoscopic myotomy (POEM) predicts improvement in postoperative eckardt score.

BACKGROUND: Peroral endoscopic myotomy (POEM) is a mainstay of treatment for achalasia. Tailored myotomy based on compliance, as measured with impedance planimetry (FLIP), has yet to be described. In this study we describe the associations between Eckardt score, postoperative GERD, and compliance. METHODS: A retrospective review of a prospectively maintained database was performed, evaluating patients who underwent POEM and intraoperative FLIP between January 2019 and November 2021. Group comparisons were made using two-tailed Wilcoxon rank-sum and Fisher's exact tests. Spearman's correlation coefficients (r) were used to assess the relationship between compliance and outcomes, all with two-tailed statistical significance of p < 0.05. RESULTS: Thirty five patients underwent POEM with intraoperative FLIP. At a 30 mL and 40 mL fill, respectively, compliance increased by 80% (180 ± 152%) and 77% (177 ± 131%) from pre to post myotomy. Mean Eckardt score improved from 5.5 ± 2.6 preoperatively to 1.3 ± 1.6 and 1.8 ± 1.9 at first and second follow up, respectively. Median times to first and second follow up were 22 days (IQR 16-23) and 65 days (IQR 58-142). A higher compliance at 40 mL fill was moderately associated with lower Eckardt score at first (r = -0.49, p = 0.012) and second (r = -0.64, p = 0.014) follow up. Post myotomy compliance ≥ 125 mm3/mmHg at 40 mL fill was associated with lower Eckardt scores, < 3, at first (0.4 ± 0.5 vs 1.8 ± 1.3, p = 0.008) and second (0.4 ± 0.5, vs 2.0 ± 1.4, p = 0.027) follow up. Compliance ≥ 125 mm3/mmHg performed better than previously defined ideal ranges of DI and CSA in predicting postoperative Eckardt scores. Compliance was not significantly associated with development of postoperative GERD. CONCLUSIONS: A target post myotomy compliance of ≥ 125 mm3/mmHg at a 40 mL fill is associated with normal Eckardt scores at first and second postoperative visits, and performs better than previously defined ideal ranges of DI and CSA in predicting post-operative Eckardt scores. Compliance is a poor predictor of developing GERD after POEM.

Endoscopic severity of gastric sleeve stenosis can be quantified using impedance planimetry.

BACKGROUND: Gastric sleeve stenosis (GSS) is an adverse event following sleeve gastrectomy for which objective tools are needed for diagnosis and treatment. Endoscopic treatment with serial pneumatic balloon dilation may relieve symptoms and prevent the need for conversion to Roux-en-Y gastric bypass. Endoluminal functional impedance planimetry (EndoFLIP) is an endoscopic tool that measures luminal diameter and distensibility indices (DI) and could be used to characterize severity of GSS. METHODS: This was a retrospective analysis of a prospective database of patients referred for symptoms suggestive of GSS. Severity was determined at each endoscopy by a bariatric endoscopist blinded to EndoFLIP measurements. Successive pneumatic balloon dilations were performed until symptoms resolved; failure was defined as referral for conversion. EndoFLIP measurements of stenosis diameter and DI were obtained pre- and post-dilation. Primary outcomes were pre- and post-dilation luminal diameter and DI of GSS. Secondary outcomes were endoscopic severity of GSS, patient characteristics, and need for surgical revision. RESULTS: 26 patients were included; 23 (85%) were female. Mean age was 45.3 (± 9.9) years. Mean number of dilations was 2.4 (± 1.3) and 10 (38%) patients were referred for conversion. Mild, moderate, and severe GSS was found in 10 (38%), 6 (23%), and 10 (38%) patients, respectively. Moderate and severe GSS underwent more dilations (2.5 ± 1.0 and 3.2 ± 1.6) than mild GSS (1.8 ± 0.8) and were more likely to be referred for conversion. Both pre- and post-dilation diameters were significantly larger in mild versus moderate or severe GSS. Additionally, pre- and post-dilation DI at 30 ml were significantly higher for mild compared to moderate and severe GSS. DISCUSSION: EndoFLIP measurements correlate well with endoscopic assessment of GSS. While more data are needed to determine ideal balloon size and threshold measurements, our results suggest EndoFLIP may help expedite diagnosis and treatment of GSS.

Target distensibility index on impedance planimetry during fundoplication by choice of wrap and choice of bougie.

INTRODUCTION: Impedance planimetry (FLIP) provides objective feedback to optimize fundoplication outcomes. Ideal FLIP ranges for differing wraps and bougies have not yet been established. We report FLIP measurements during fundoplication grouped by choice of wrap and bougie with associated outcomes. METHODS: A retrospective review of a prospective gastroesophageal database was performed for all Nissen or Toupet fundoplication with intraoperative FLIP using an 8-cm catheter, 30-mL and/or 40-mL fill and/or 16-cm catheter, 60-mL fill. Surgeons used no bougie, the FLIP balloon as bougie, or a hard bougie. Outcomes included perioperative data, Reflux Symptom Index, GERD-HRQL, Dysphagia scores, need for dilation, postoperative EGD findings, and hernia recurrence. Group comparisons were made using two-tailed Kruskal-Wallis and Fisher's exact tests. RESULTS: Between 2016 and 2022, 333 patients underwent fundoplication and intraoperative FLIP. Procedures included Toupet with hard bougie (TFHB, N = 147), Toupet with FLIP bougie (TFFB, N = 69), Toupet without bougie (TFNB, N = 78), Nissen with hard bougie (NFHB, n = 20), or Nissen with FLIP bougie (NFFB, N = 19). FLIP measurements at 30-mL/40-mL fills varied significantly between groups, notably distensibility index at crural closure (CCDI) and post-fundoplication (FDI). No significant differences in FLIP measurements were seen between those who developed poor postoperative outcomes and those who did not, including when grouping by choice of wrap and bougie. At a 40-mL fill, abnormal motility patients with CCDI > 3.5 mm2/mmHg developed zero postoperative dysphagia. TFFB abnormal motility patients with CCDI > 3.5 mm2/mmHg or FDI > 3.6 mm2/mmHg developed zero postoperative dysphagia. CONCLUSION: Intraoperative FLIP measurements vary by fundoplication and bougie choice. A CCDI > 3.5 mm2/mmHg (40 mL fill) should be sought in abnormal motility patients, regardless of wrap or bougie, to avoid postoperative dysphagia. TFFB abnormal motility patients with FDI > 3.6 mm2/mmHg (40 mL fill) also developed zero postoperative dysphagia. FDI > 6.2 mm2/mmHg (40 mL fill) was seen in all postoperative hernia recurrences.

The impact of pneumoperitoneum on esophagogastric junction distensibility during anti-reflux surgery.

OBJECTIVE: We aimed to quantify the contribution of pneumoperitoneum on compliance of the esophagogastric junction (EGJ) during anti-reflux surgery. BACKGROUND: Compliance of the EGJ is reduced with anti-reflux surgery. EndoFLIP® planimetry can be used to assess dynamic changes of EGJ compliance intraoperatively. It is unclear how pneumoperitoneum impacts intraoperative measurements by EndoFLIP® and the implications thereof on validity of the results. Therefore, determining variability in EndoFLIP® measurements based on pneumoperitoneum is warranted to establish guidelines to interpret clinical outcomes. METHODS: Primary anti-reflux surgery was performed on 39 consecutive patients with pathologic reflux. Intraoperative EGJ measurements including distensibility index (DI), cross-sectional area (CSA), and intrabag pressure were collected using EndoFLIP® at 0, 10, and 15 mmHg of intraperitoneal pressure. Data were acquired pre-procedure, post-hiatal hernia repair, and post-LES augmentation with fundoplications. RESULTS: Patients underwent Nissen (13.2%), Toupet (68.4%), LINX (10.5%), or Hill-fundoplications (7.9%). There was no difference between 0 and 10 mmHg of pneumoperitoneum in CSA, pressure, or DI measurements pre-procedure; however, there was a difference between 0 and 15 mmHg in pressure (p = 0.016) and DI (p = 0.023) measurements. After LES augmentation, 10 mmHg intraperitoneal pressure reduced DI, though the absolute difference is small (2.0 vs. 1.5 mm2/mmHg, p = 0.002). CONCLUSION: Pneumoperitoneum affected EGJ distensibility at 15 mmHg, but not 10 mmHg, of insufflation prior to anti-reflux procedures. After anti-reflux surgery, there was a significant variance between 0 and 10 mmHg of pneumoperitoneum in pressure and distensibility. The change in pressure appears linear and needs to be considered if procedural modifications are performed based on intraoperative findings and when evaluating clinical outcomes.

Impedance planimetry (EndoFLIP™) reveals changes in gastroesophageal junction compliance during fundoplication.

INTRODUCTION: Compliance is the ability of a hollow organ to dilate and increase volume with an increase in pressure, an accurate representation of food bolus transit through the gastroesophageal junction (GEJ). Impedance planimetry system can calculate compliance (change in volume over pressure) and distensibility (cross-sectional area over pressure) of the GEJ. We aim to describe the changes in compliance during anti-reflux surgery and hypothesize that compliance is a better predictor of patient outcomes than distensibility (DI). METHODS AND PROCEDURES: A review of a prospectively maintained quality database was performed. Patients with FLIP measurements during laparoscopic fundoplication between August 2018 and June 2021 were included. GEJ compliance and DI were measured after hernia reduction, cruroplasty, and fundoplication. Patient-reported outcomes were collected through standardized surveys up to 2 years after surgery. A scatter plot was used to identify a correlation between compliance and DI. Comparisons of measurements between time points were made using paired t-tests. Spearman's correlation coefficients (ρ), Wilcoxon rank-sum, and chi-square tests were used to evaluate associations between measurements and outcomes. RESULTS: One hundred and forty-four patients underwent laparoscopic fundoplication. Compliance is strongly associated with DI (r = 0.96), and a comparison of measurements showed similar trends at specific time points during the operation. After hernia reduction, compliance at the GEJ was 168 ± 74 mm3/mmHg, cruroplasty 79 ± 39 mm3/mmHg, and fundoplication 90 ± 33 mm3/mmHg (all comparisons p < 0.05). GEJ compliance of 80-92 mm3/mmHg after fundoplication was associated with the best patient-reported outcome scores. A compliance of ≤ 79 mm3/mmHg had the highest percentage of patients who reported dysphagia. CONCLUSIONS: Compliance and DI are strongly associated displaying the same directional change during anti-reflux surgery. GEJ compliance of 80-92 mm3/mmHg revealed the best patient-reported outcome scores, and avoiding a compliance ≤ 79 mm3/mmHg may prevent postoperative dysphagia. Therefore, GEJ compliance is an underutilized FLIP measurement warranting further investigation.

Significant changes in impedance planimetry (EndoFLIP™) measurements after peroral pyloromyotomy for delayed gastric emptying.

BACKGROUND: The endoluminal functional lumen imaging probe (FLIP) can be used to obtain real-time measurements of the diameter (Dmin), cross-sectional area (CSA), and distensibility of the pylorus before and after peroral pyloromyotomy (POP), an emerging endoscopic treatment for delayed gastric emptying. Our study aims to report our single-center experience in performing POP with FLIP measurements before and after pyloromyotomy. METHODS: A retrospective review of a prospectively maintained gastroesophageal database was performed. Demographic and perioperative data, including intraoperative FLIP measurements of the pylorus before and after POP, were analyzed. Measurements were compared using paired t tests. RESULTS: Thirty-four patients underwent POP between February 2017 and July 2020. Twenty-three (67.7%) patients were male and the average age was 59 years. The etiology of delayed gastric emptying was post-vagotomy in 22 patients, idiopathic gastroparesis in 7 patients, and diabetic gastroparesis in 5 patients. There were no significant differences in pre-myotomy or post-myotomy FLIP measurements when comparing the post-vagotomy versus the gastroparesis groups. There were significant increases in Dmin, CSA, and distensibility index when comparing pre-myotomy and post-myotomy readings for all patients (all p < 0.001). At follow-up, 64.7% of patients reported resolution of all symptoms. CONCLUSION: POP is an effective intervention in patients with delayed gastric emptying. Significant changes in FLIP measurements before and after POP suggest that FLIP may be a useful adjunct in guiding the management of delayed gastric emptying.

Crural closure, not fundoplication, results in a significant decrease in lower esophageal sphincter distensibility.

INTRODUCTION: The esophagogastric junction (EGJ) is a complex anti-reflux barrier whose integrity relies on both the intrinsic lower esophageal sphincter (LES) and extrinsic crural diaphragm. During hiatal hernia repair, it is unclear whether the crural closure or the fundoplication is more important to restore the anti-reflux barrier. The objective of this study is to analyze changes in LES minimum diameter (Dmin) and distensibility index (DI) using the endoluminal functional lumen imaging probe (FLIP) during hiatal hernia repair. METHODS: Following implementation of a standardized operative FLIP protocol, all data were collected prospectively and entered into a quality database. This data were reviewed retrospectively for all patients undergoing hiatal hernia repair. FLIP measurements were collected prior to hernia dissection, after hernia reduction, after cruroplasty, and after fundoplication. Additionally, subjective assessment of the tightness of crural closure was rated by the primary surgeon on a scale of 1 to 5, 1 being the loosest and 5 being the tightest. RESULTS: Between August 2018 and February 2020, 97 hiatal hernia repairs were performed by a single surgeon. FLIP measurements collected using a 40-mL volume fill without pneumoperitoneum demonstrated a significant decrease in LES Dmin (13.84 ± 2.59 to 10.27 ± 2.09) and DI (6.81 ± 3.03 to 2.85 ± 1.23 mm2/mmHg) after crural closure (both p < 0.0001). Following fundoplication, there was a small, but also statistically significant, increase in both Dmin and DI (both p < 0.0001). Additionally, subjective assessment of crural tightness after cruroplasty correlated well with DI (r = - 0.466, p < 0.001) and all patients with a crural tightness rating ≥ 4.5 (N = 13) had a DI < 2.0 mm2/mmHg. CONCLUSION: Cruroplasty results in a significant decrease in LES distensibility and may be more important than fundoplication in restoring EGJ competency. Additionally, subjective estimation of crural tightness correlates well with objective FLIP evaluation, suggesting surgeon assessment of cruroplasty is reliable.

Impedance planimetry (EndoFLIP™) after magnetic sphincter augmentation (LINX®) compared to fundoplication.

INTRODUCTION: Functional luminal imaging probe (FLIP) use during laparoscopic fundoplication (LF) for gastroesophageal reflux disease is well described. However, there is a lack of data on FLIP measurements during magnetic sphincter augmentation (MSA). This study aims to report our institutional experience in performing FLIP during MSA and to compare these measurements to those obtained during Nissen and Toupet fundoplication. METHODS AND PROCEDURES: A retrospective review of a prospectively maintained quality database was performed. Patients who underwent MSA or LF and had FLIP measurements between April 2018 and June 2021 were included. FLIP measurements at the gastroesophageal junction (GEJ) were recorded without pneumoperitoneum at 40 mL balloon fill after hernia reduction, cruroplasty, and MSA or fundoplication. Reflux symptom index (RSI), GERD-HRQL, and dysphagia score were collected up to 2 years. Group comparisons were made using two-tailed Wilcoxon rank-sum and χ2 tests, with statistical significance of p < 0.05. RESULTS: Twenty-seven patients underwent MSA and 100 patients underwent LF (66% Toupet, 34% Nissen). Type III hiatal hernia was present in 3.7% of MSA patients versus over 50% for fundoplication patients. Minimum diameter, cross-sectional area, and distensibility index (DI) were lower after MSA device placement compared to Nissen or Toupet fundoplication (p < 0.05). Postoperative follow-up showed no differences in RSI, GERD-HRQL, and dysphagia score between MSA and Nissen fundoplication (p > 0.05). CONCLUSION: Intraoperative impedance planimetry provided objective information regarding the geometry of the GEJ during MSA. The ring of magnetic beads restores the anti-reflux barrier and transiently opens with food bolus and belching. The magnetic force of the beads may explain why the DI after MSA is lower yet postoperative quality of life is no different than Nissen fundoplication.

Quantifying physiologic parameters of the gastroesophageal junction during re-operative anti-reflux surgery.

BACKGROUND: Hiatal hernia re-approximation during index anti-reflux surgery (ARS) contributes approximately 80% of overall change in distensibility index (DI) and, potentially, compliance of the gastroesophageal (GEJ), while sphincter augmentation contributes approximately 20%. Whether this is seen in re-operative ARS is unclear. We quantify the physiologic parameters of the GEJ at each step of robotic re-operative ARS and compare these to index ARS. METHODS: Robotic ARS with hiatal hernia repair was performed on 195 consecutive patients with pathologic reflux utilizing EndoFLIP™, of which 26 previously had ARS. Intra-operative GEJ measurements, including cross-sectional area (CSA), pressure, DI, and high-pressure zone (HPZ) length were collected pre-repair, post-diaphragmatic re-approximation, post-mesh placement, and post-lower-esophageal sphincter (LES) augmentation. RESULTS: Both cohorts were similar by sex and BMI and underwent similar procedures. The re-operative cohort was older (60.6 ± 15.3 vs. 52.7 ± 16.2 years, p = 0.03), had more frequent pre-operative dysphagia (69.2% vs. 42.6%, p = 0.01) and esophageal dysmotility on barium swallow (75.0% vs. 35.0%, p < 0.001) but lower rates of hiatal hernia on endoscopy (30.8% vs. 68.7%, p < 0.001) compared to index procedures. Among the re-operative cohort, the CSA decreased by 34 (IQR - 80, - 15) mm2 and DI 1.1 (IQR - 2.4, - 0.6) mm2/mmHg (both p < 0.001). Pressure increased by 11.2 (IQR 4.7, 14.9) mmHg and HPZ by 1.5 (1,2) cm (both p < 0.001). These changes were similar to those seen in index ARS. Diaphragmatic re-approximation contributed to a greater percentage of overall change to the GEJ than did the augmentation procedure, with 72% of the change in DI occurring during hiatal closure, similar to that seen during index ARS. CONCLUSIONS: During re-operative ARS, dynamic intra-operative monitoring can quantify the effects of each operative step on GEJ physiologic parameters. Diaphragmatic re-approximation appears to have a greater effect on GEJ physiology than does LES-sphincter augmentation during both index and re-operative ARS.

Changes in impedance planimetry (EndoFLIP) measurements at follow-up after peroral endoscopic myotomy (POEM).

BACKGROUND: Numerous studies show changes in functional lumen imaging probe (FLIP) measurements after myotomy during peroral endoscopic myotomy (POEM), but few report on FLIP measurements at follow-up esophagogastroduodenoscopy (EGD). The purpose of this study was to compare perioperative FLIP measurements to those at follow-up EGD. METHODS: Patients who underwent POEM with FLIP in the operating room and POEM patients who had EGD with FLIP at follow-up were included. FLIP measurements, including diameter (Dmin), pressure, cross-sectional area (CSA), and distensibility index (DI), were analyzed at a 30-mL balloon fill. Differences between measurements at different timepoints were assessed using a two-tailed Wilcoxon signed-rank test. RESULTS: A total of 97 patients who underwent POEM and 28 who underwent EGD with FLIP were analyzed. The average age was 63 ± 18 years and 46.4% of the patients were male. Mean preoperative Eckardt score was 6.5 ± 4.8, decreasing to 1.6 ± 2.0 at follow-up. EGDs were performed at a median of 15 months after surgery. When compared to mean measurements obtained post-myotomy, at the time of EGD, pressure was found to be significantly lower (p = 0.007) and DI significantly higher (p = 0.045). Of the patients who underwent EGD, 70.8% had an increase in DI, 55.6% had evidence of reflux esophagitis, and 81.0% met diagnostic criteria for reflux on esophageal pH monitoring. However, there was no correlation with the development of esophagitis or reflux and increase or decrease in DI at follow-up. CONCLUSIONS: There are significant changes in FLIP measurements between the time of surgery and at follow-up EGD. These results suggest that esophageal remodeling may cause changes in lower esophageal sphincter geometry after POEM and postoperative FLIP targets immediately post-myotomy may need to be adjusted to account for these changes.

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.

Experience-based expert consensus on the intra-operative usage of the Endoflip impedance planimetry system.

INTRODUCTION: The Endoluminal Functional Lumen Imaging Probe (Endoflip™) is a balloon-based catheter that provides real-time, objective feedback regarding the distensibility of any sphincter in the gastrointestinal tract. Usage of the Functional Lumen Imaging Probe (FLIP) has not been standardized, which has limited the interpretation and generalizability of published data. The purpose of this consensus statement is to provide a standardized protocol for obtaining FLIP measurements in order to create a more uniform approach to data collection. METHODS: Five expert foregut surgeons, all of whom utilize the FLIP system in their daily practice, convened on March 19, 2019, to create a standardized protocol for obtaining FLIP measurements during hiatal hernia repair and fundoplication, magnetic sphincter augmentation, laparoscopic Heller myotomy, and peroral endoscopic myotomy. Existing literature was presented and reviewed. Each step of the protocol was discussed in detail until a unanimous consensus was reached. RESULTS: A standardized protocol was developed for obtaining FLIP measurements during hiatal hernia repair and fundoplication, magnetic sphincter augmentation, laparoscopic Heller myotomy, and peroral endoscopic myotomy. CONCLUSION: The FLIP impedance planimetry system is the only technology available that provides surgeons an objective way to assess the tightness of a fundoplication or adequacy of a myotomy during an operation. While considerable research remains to correlate FLIP measurements to patient outcomes, this consensus statement will provide standardization of data collection among FLIP users that will enhance the understanding of future study results.