Magnetic Sphincter Augmentation for Laryngopharyngeal Reflux: An Assessment of Efficacy and Predictors of Outcome.

INTRODUCTION: Magnetic sphincter augmentation (MSA) is an effective treatment for typical reflux symptoms, but data on its impact on laryngopharyngeal reflux (LPR) is limited. This study aimed to determine the efficacy of MSA for LPR and to identify predictors of outcome. METHODS: This was a retrospective review of 775 patients who underwent MSA between 2013 and 2021. LPR was defined as presence of atypical reflux symptoms and a reflux symptom index (RSI) score >13. Favorable outcome was defined as primary symptom resolution, freedom from proton pump inhibitors, and five-point improvement or RSI score normalization. Preoperative clinical, high-resolution manometry, and impedance-pH data were analyzed for impact on favorable outcome using univariate followed by multivariable analysis. RESULTS: There were 128 patients who underwent MSA for LPR. At a mean (SD) follow-up of 13 (5.4) months, favorable outcome was achieved by 80.4% of patients, with median (IQR) RSI score improving from 29 (22-35) to 9 (4-17), (P < 0.001). Independent predictors of favorable outcome on multivariable analysis included LPR with typical reflux symptoms [OR (95% CI): 8.9 (2.3-31.1), P = 0.001], >80% intact swallow on high-resolution manometry [OR (95% CI): 3.8 (1.0-13.3), P = 0.035], upper esophageal sphincter (UES) resting pressure >34 mmHg [OR (95% CI): 4.1 (1.1-14.1), P = 0.027] and short total proximal acid clearance time [OR (95% CI): 1.1 (1.0-1.1), P = 0.031]. Impedance parameters including number of LPR events, full column reflux and proximal acid exposure events were similar between outcome groups (P > 0.05). CONCLUSION: MSA is an effective surgery for patients with LPR. Patients with concomitant typical reflux symptoms, normal esophageal body motility, and competent UES benefit the most from surgery. Individual impedance-pH parameters were not associated with outcome.

Impact of Change in Sizing Protocol on Outcome of Magnetic Sphincter Augmentation.

OBJECTIVE: To evaluate and compare magnetic sphincter augmentation (MSA) device sizing protocols on postoperative outcomes and dysphagia. SUMMARY BACKGROUND DATA: Among predictors of dysphagia after MSA, device size is the only factor that may be modified. Many centers have adopted protocols to increase device size. However, there is limited data on the impact of MSA device upsizing protocols on the surgical outcomes. METHODS: Patients who underwent MSA were implanted with 2 or 3-beads above the sizing device's pop-off point (POP). Clinical and objective outcomes >1-year after surgery were compared between patients implanted with POP+2-vs-POP+3 sizing protocols. Multiple subgroups were analyzed for benefit from upsizing. Pre- and postoperative characteristics were compared between size patients received, regardless of protocol. RESULTS: A total of 388 patients were implanted under POP+2 and 216 under POP+3. At a mean of 14.2(7.9) months pH normalization was 73.6% and 34.1% required dilation, 15.9% developed persistent dysphagia, and 4.0% required removal. Sizing protocol had no impact on persistent dysphagia ( P =0.908), pH normalization ( P =0.822), or need for dilation ( P =0.210) or removal ( P =0.191). Subgroup analysis found that upsizing reduced dysphagia in patients with <80 percent peristalsis (10.3-vs-31%, P =0.048) or DCI >5000 (0-vs-30.4%, P =0.034). Regardless of sizing protocol, as device size increased there was a stepwise increase in percent male sex ( P <0.0001), BMI>30 ( P <0.0001), and preoperative hiatal hernia>3 cm ( P <0.0001), LA grade C/D esophagitis ( P <0.0001), and DeMeester score ( P <0.0001). Increased size was associated with decreased pH-normalization ( P <0.0001) and need for dilation ( P =0.043) or removal ( P =0.014). CONCLUSIONS: Upsizing from POP+2 to POP+3 does not reduce dysphagia or affect other MSA outcomes; however, patients with poor peristalsis or hypercontractile esophagus do benefit. Regardless of sizing protocol, preoperative clinical characteristics varied among device sizes, suggesting size is not a modifiable factor, but a surrogate for esophageal circumference.

Esophageal body adaptation to Nissen fundoplication: Increased esophagogastric outflow resistance yields delayed and sustained peristaltic contractions without increased amplitude.

BACKGROUND: Improvement in lower esophageal sphincter (LES) competency after laparoscopic Nissen fundoplication (LNF) is well established, yet esophageal body physiology data are limited. We aimed to describe the impact of LNF on whole esophagus physiology using standard and novel manometric characteristics. METHODS: A cohort of patients with an intact fundoplication without herniation and no postoperative dysphagia were selected and underwent esophageal manometry at one-year after surgery. Pre- and post-operative manometry files were reanalyzed using standard and novel manometric characteristics and compared. KEY RESULTS: A total of 95 patients were included in this study. At 16.1 (8.7) months LNF increased LES overall and abdominal length and resting pressure (p < 0.0001). Outflow resistance (IRP) increased [5.8 (3-11) to 11.1 (9-15), p < 0.0001] with a 95th percentile of 20 mmHg in this cohort of dysphagia-free patients. Distal contractile integral (DCI) also increased [1177.0 (667-2139) to 1321.1 (783-2895), p = 0.002], yet contractile amplitude was unchanged (p = 0.158). There were direct correlations between pre- and post-operative DCI [R: 0.727 (0.62-0.81), p < 0.0001] and postoperative DCI and postoperative IRP [R: 0.347 (0.16-0.51), p = 0.0006]. Contractile front velocity [3.5 (3-4) to 3.2 (3-4), p = 0.0013] was slower, while distal latency [6.7 (6-8) to 7.4 (7-9), p < 0.0001], the interval from swallow onset to proximal smooth muscle initiation [4.0 (4-5) to 4.4 (4-5), p = 0.0002], and the interval from swallow onset to point when the peristaltic wave meets the LES [9.4 (8-10) to 10.3 (9-12), p < 0.0001] were longer. Esophageal length [21.9 (19-24) to 23.2 (21-25), p < 0.0001] and transition zone (TZ) length [2.2 (1-3) to 2.5 (1-4), p = 0.004] were longer. Bolus clearance was inversely correlated with TZ length (p = 0.0002) and time from swallow onset to proximal smooth muscle initiation (p < 0.0001). Bolus clearance and UES characteristics were unchanged (p > 0.05). CONCLUSIONS & INFERENCES: Increased outflow resistance after LNF required an increased DCI. However, this increased contractile vigor was achieved through sustained, not stronger, peristaltic contractions. Increased esophageal length was associated with increased TZ and delayed initiation of smooth muscle contractions.

Gas-Bloat Syndrome after Magnetic Sphincter Augmentation: Incidence, Natural History, Risk Factors, and Impact on Surgical Outcomes Over Time.

BACKGROUND: The notion that gas-bloat syndrome (GBS) after magnetic sphincter augmentation (MSA) is less detrimental has not been substantiated by data. This study aimed to identify the incidence, natural history, risk factors, and impact on outcomes of GBS after MSA. STUDY DESIGN: Records of patients who underwent MSA at our institution were reviewed. GBS was defined as a score of 4 or more on the gas bloat-specific item within the GERD health-related quality-of-life (GERD-HRQL) questionnaire. Preoperative clinical and objective testing data were compared between those with and without GBS at 1 year using univariate followed by multivariable analysis. GBS evolution over time and its impact on outcomes were assessed in those with 1- and 2-year follow-up. RESULTS: A total of 489 patients underwent MSA. At a mean (SD) follow-up of 12.8 (2.1) months, patient satisfaction was 88.8%, 91.2% discontinued antisecretory medications, and 74.2% achieved DeMeester score normalization.At 1 year, 13.3% of patients developed GBS, and had worse GERD-HRQL scores and antisecretory medication use and satisfaction (p < 0.0001). DeMeester score normalization was comparable (p = 0.856). Independent predictors of GBS were bloating (odds ratio [OR] 1.8, p = 0.043), GERD-HRQL score greater than 30 (OR 3, p = 0.0010), and MSA size 14 or less beads (OR 2.5, p = 0.004). In a subgroup of 239 patients with 2-year follow-up, 70.4% of patients with GBS at 1 year had resolution by 2 years. The GERD-HRQL total score improved when GBS resolved from 11 (7 to 19) to 7 (4 to 10), p = 0.016. Patients with persistent GBS at 2 years had worse 2-year GERD-HRQL total scores (20 [5 to 31] vs 5 [3 to 12], p = 0.019). CONCLUSIONS: GBS affects 13.3% of patients at 1 year after MSA and substantially diminishes outcomes. However, GBS resolves spontaneously with quality-of-life improvement. Patients with preoperative bloating, high GERD-HRQL scores, or small MSA devices are at greatest risk of this complication.

Chevalier Jackson: father of endoscopic surgery, and champion of women in medicine, social justice, and public health.

BACKGROUNDS: Chevalier Jackson (1865-1958) was a pioneering force in the medical world, whose extraordinary contributions to surgery and public health have left an indelible impact. He developed the endoscope and perfected the bronchoscope, and his mastery of these tools enabled him to transform the prognosis of foreign body aspiration from 98% mortality to 98% survival. He was also a passionate advocate of public health chairing the national committee on lye legislation, which culminated in the Caustic Poison Act, responsible for poison and antidote labels. Yet Jackson's accomplishments were not limited to these. The aim of this manuscript was to shed light on Chevalier Jackson's lesser-known contributions to surgical science and culture, and to celebrate and honor the life of this remarkable surgeon. METHODS: Digital and physical historical records from the National Library of Medicine, Smithsonian Institution, Heinz History Center in Pittsburgh PA, and Sunrise Mill Museum, Montgomery County PA were reviewed for Chevalier Jackson's scientific, cultural, and social contributions to the field of surgery. RESULTS: Among his lesser-known contributions, Chevalier Jackson was the first to describe erosive esophagitis. He developed the first standardized tracheotomy procedure, still in use today. He was ahead of his time in many ways, pioneering a multidisciplinary approach to medicine, advocating for patient-centered care, and advancing the inclusion of women in the medical profession. CONCLUSION: Chevalier Jackson's legacy extends far beyond the tools and techniques he invented. He was a champion of social justice, a protector of patients, and an inspiration to medical professionals across the globe.

The Utility of Symptom Association Probability (SAP) in Predicting Outcome After Laparoscopic Fundoplication in Patients with Abnormal Esophageal Acid Exposure.

INTRODUCTION: Abnormal DeMeester score on pH monitoring is a well-established predictor of favorable outcome after antireflux surgery (ARS). Esophageal pH monitoring also facilitates analysis of the temporal association between symptoms and reflux episodes. This association can be expressed with several symptom-reflux association indices with symptom association probability (SAP) being the most reliable. SAP is often used as an adjunct to DeMeester score during preoperative assessment of patients seeking ARS. However, data on the utility of SAP in predicting ARS outcome is limited. The aim of this study was to determine the utility of SAP as an adjunct to DeMeester score in predicting outcomes after fundoplication. METHODS: Records of patients who underwent primary fundoplication from 2015 to 2021 were reviewed. Patients with a preoperative DeMeester score >14.7 on Bravo pH monitoring were included. A SAP >95% was considered SAP-positive. Favorable outcome was defined as freedom from proton pump inhibitors (PPIs) and patient satisfaction at 1 year postoperatively. Outcomes were compared based on the presence and number of SAP-positive symptoms, individual typical and atypical SAP-positive symptoms, and within demographic, clinical, and reflux severity subgroups. RESULTS: The final study population consisted of 597 patients (71.4% female) with a median (IQR) age of 59.0 (49-67). At a mean (SD) follow-up of 10.5 (8) months, 82.0% patients achieved favorable outcome (satisfaction and freedom from PPI), freedom from PPI was 91.7%, and satisfaction was 87.4%. SAP was positive in 430 (72.0%) patients, of which 221 (37.0%) had one SAP-positive symptom, 164 (27.5%) had two SAP-positive symptoms, and 45 (7.5%) had all three SAP-positive symptoms. There was no association between having at least one SAP-positive symptom and favorable outcome (p=0.767). There was no difference in favorable outcome between patients with one, two, or all SAP-positive symptoms (0.785). Outcomes were comparable for SAP-positive typical (p=0.873) and atypical symptoms (p=1.000) and all individual symptoms (p>0.05). Outcomes were also comparable within all subgroups (p>0.05). CONCLUSION: Symptom association probability with an abnormal DeMeester score did not enhance the prediction of antireflux surgery outcome. These findings suggest that SAP should not be used in surgical decision-making in patients with objective evidence of reflux.

Need for frequent dilations after magnetic sphincter augmentation: an assessment of associated factors and outcomes.

BACKGROUND: Dysphagia is the most common complaint after magnetic sphincter augmentation (MSA), with nearly one-third of patients requiring at least one dilation following MSA. A subset of patients require frequent dilations, but there is a paucity of data on the characteristics of this population. This study aimed to identify predictors of the need for frequent dilations within the first year after implant and to assess these patients' outcomes. METHODS: This is a retrospective review of prospectively collected data of patients who underwent MSA over an 8-year period. Frequent dilations were defined as 2 or more dilations within 1 year of surgery. Patients completed baseline and 1-year postoperative GERD-HRQL questionnaires and objective physiology testing. Baseline demographic, clinical characteristics, and objective testing data were compared between patients who did and did not require frequent dilations. RESULTS: A total of 697 (62.7% female) patients underwent MSA, with 62 (8.9%) patients requiring frequent dilation. At a mean (SD) of 12.3 (3.4) months follow-up, the frequent dilation group had higher median GERD-HRQL total scores (21.0 vs. 5.0, p < 0.001), PPI use (20.8% vs.10.1%, p = 0.023), dissatisfaction (46.7% vs. 11.6%, p < 0.001), and device removal (25.8% vs. 2.2%, p < 0.001) rates. Acid normalization was comparable (p = 0.997). Independent predictors of frequent dilation included preoperative odynophagia (OR 2.85; p = 0.001), IRP > 15 mmHg (OR 2.88; p = 0.006), and > 30% incomplete bolus clearance (OR 1.94; p = 0.004). At a mean (SD) of 15.7 (10.7) months, 28 (45.1%) patients underwent device removal after frequent dilation. Independent predictors of device removal after frequent dilation within 5 years of surgery were preoperative odynophagia (OR 7.18; p = 0.042), LES resting pressure > 45 mmHg (OR 28.5; p = 0.005), and ≥ 10% failed swallows (OR 23.5; p < 0.001). CONCLUSIONS: The need for frequent dilations after MSA is a marker for poor symptom control, dissatisfaction, and device removal. Patients with preoperative odynophagia, high LES pressures, and poor esophageal motility should be counseled of their risk for these poor outcomes.

The impact of delayed gastric emptying as measured by gastric emptying scintigraphy on the outcome of magnetic sphincter augmentation.

INTRODUCTION: The impact of delayed gastric emptying (DGE) on the outcome of anti-reflux surgery (ARS) is controversial. There is concern that poor gastric emptying diminishes outcomes. Magnetic sphincter augmentation (MSA) may have a comparatively mild impact on gastric physiology, but the relationship between DGE and MSA outcomes is unknown. This study aims to evaluate the relationship between objective DGE and MSA outcomes over time. METHODS: Patients who completed gastric emptying scintigraphy (GES) prior to MSA between 2013 and 2021 were included. DGE was defined as a 4 h retention > 10% or half emptying time > 90 min on GES. Outcomes were compared between DGE and normal gastric emptying (NGE) groups at 6 months, 1 and 2 years. Sub-analysis of patients with severe (> 35%) DGE and correlation analysis between 4-h retention and symptom and acid-normalization were performed. RESULTS: The study population consisted of 26 (19.8%) patients with DGE and 105 with NGE. DGE was associated with more 90-days readmissions (18.5 vs 2.9%, p = 0.009). At 6 months patients with DGE had higher median (IQR) GERD-HRQL total [17.0(10-29) vs 5.5(3-16), p = 0.0013], heartburn [1(1-3) vs 0(0-1), p = 0.0010) and gas-bloat [4(2-5) vs 2(1-3), p = 0.033] scores. Outcomes at 1 and 2 years follow-up were comparable (p > 0.05). From 6 months to 1-year the gas-bloat score decreased from 4(2-5) to 3(1-3), p = 0.041. Total and heartburn scores decreased, but not significantly. Severe DGE (n = 4) patients had lower antiacid medication freedom at 6 months (75 vs 87%, p = 0.014) and 1-year (50 vs 92%, p = 0.046). There were non-significant trends for higher GERD-HRQL scores, dissatisfaction, and removal rates in severe DGE at 6 months and 1-year. There was a weak correlation between 4-h retention and 6-month GERD-HRQL total score [R = 0.253, 95%CI (0.09-0.41), p = 0.039], but not acid-normalization (p > 0.05). CONCLUSION: Outcomes after MSA are diminished early on in patients with mild-to-moderate DGE, but comparable by 1 year and durable at 2 years. Severe DGE outcomes may be suboptimal.

Ineffective esophageal motility: The impact of change of criteria in Chicago Classification version 4.0 on predicting outcome after magnetic sphincter augmentation.

BACKGROUND: The most recent update of the Chicago Classification (CCv4.0) attempts to provide a more clinically relevant definition for ineffective esophageal motility (IEM). The impact of this new definition on predicting outcome after antireflux surgery is unknown. The aim of this study was to compare utility of IEM diagnosis based on CCv4.0 to CCv3.0 in predicting surgical outcome after magnetic sphincter augmentation (MSA) and to assess any additional parameters that hold value in future definitions. METHODS: Records of 336 patients who underwent MSA at our institution between 2013 and 2020 were reviewed. Preoperative manometry files were re-analyzed using both Chicago Classification version 3.0 (CCv3.0) and CCv4.0 definitions of IEM. The utility of each IEM definition in predicting surgical outcome was then compared. Individual manometric components and impedance data were also assessed. KEY RESULTS: Immediate dysphagia was reported by 186 (55.4%) and persistent dysphagia by 42 (12.5%) patients. CCv3.0 IEM criteria were met by 37 (11%) and CCv4.0 IEM by 18 (5.4%) patients (p = 0.011). CCv3.0 and CCv4.0 IEM were equally poor predictors of immediate (AUC = 0.503 vs. 0.512, p = 0.7482) and persistent (AUC = 0.519 vs. 0.510, p = 0.7544) dysphagia. The predicted dysphagia probability of less than 70% bolus clearance (BC) was 17.4%, higher than CCv4.0 IEM at 16.7%. When BC was incorporated into CCv4.0 IEM criteria, the probability increased significantly to 30.0% (p = 0.0042). CONCLUSIONS & INFERENCES: The CCv3.0 and CCv4.0 of IEM are poor predictors of dysphagia after MSA. Adding BC to the new definition improves its predictive utility and should be considered in future definitions.

Acute superior mesenteric artery syndrome with complete foregut obstruction following Nissen fundoplication.

INTRODUCTION AND IMPORTANCE: Superior mesenteric artery syndrome (SMAS) is a rare but severe condition characterized by acute angulation of the aortomesenteric axis. It can result in compression and obstruction of the third part of the duodenum leading to life-threatening dilation and perforation of the proximal duodenum and stomach. PRESENTATION OF CASE: We report a rare case of a patient with postural abnormality secondary to multiple sclerosis and a borderline but normal aortomesenteric axis who developed SMAS following a paraesophageal hernia repair with Nissen fundoplication complicated by massive gastric dilation and perforation secondary due to a closed-loop-like foregut obstruction. The patient was managed with emergent damage control surgery and washout with delayed duodenojejunostomy for SMAS. CLINICAL DISCUSSION: SMAS with partial obstruction can mimic common complications after Nissen fundoplication such as gas-bloat syndrome. SMAS with complete obstruction is a life-threatening surgical emergency. Postoperative weight loss, large hiatal hernia reduction, gas-bloat syndrome and postural changes in this patient may have contributed to an altered aortomesenteric axis and promoted the development of SMAS. Identifying possible predisposing factors should heighten vigilance and prompt radiological evaluation and surgical management to prevent life-threatening complications. CONCLUSION: SMAS after Nissen fundoplication is a potentially life-threatening complication that presents with non-specific symptoms mimicking common complications like gas-bloat syndrome. A high index of suspicious should prompt early radiological evaluation in patients with predisposing factors.

Predictors of favorable outcome after pyloroplasty for gastroparesis: should response to pyloric dilation or Botox injection be used as a marker of surgical outcome?

INTRODUCTION: Pyloroplasty and gastric peroral endoscopic myotomy (G-POEM) are effective surgeries for gastroparesis. The primary aim of this study was to evaluate outcomes of pyloroplasty and G-POEM in patients with gastroparesis and determine factors associated with favorable outcome. The secondary aim was to assess the utility of clinical response to preoperative pyloric dilation or botulinum toxin injection (Botox) on surgical outcome, a factor conventionally used as a favorable marker. METHODS: There were 204 patients who underwent pyloroplasty (n = 177) or G-POEM (n = 27) for gastroparesis at our institution from 2014 to 2021. Demographic and clinical parameters were analyzed to assess their impact on surgical outcome. A subgroup of patients who had pyloric dilation or Botox injection were assessed separately. Favorable outcome was defined as patient reported complete resolution of the predominant gastroparesis symptom. RESULTS: Favorable outcome was achieved in 78.4% of patients (pyloroplasty: 79.7% and G-POEM: 70.4%, p = 0.274). Among 61 patients where pre- and postoperative gastric emptying studies (GES) were available, mean 4-hour retention significantly improved from 33.5 to 15.0% (p < 0.001) and 77.0% of patients achieved normalization. Favorable outcome was not significantly impacted by etiology of gastroparesis (p = 0.120), GERD (p = 0.518), or primary gastroparesis symptom (p = 0.244). Age ≥ 40 was a significant predictor of favorable surgical outcome on multivariate analysis [OR: 2.476 (1.224-5.008), p = 0.012]. Among the patients who had preoperative dilation (n = 82) or Botox injection (n = 46), response to these interventions was not a predictor of favorable surgical outcome (p = 0.192 and 0.979, respectively). However, preoperative Botox injection, regardless of response to injection, was associated with favorable surgical outcome [OR: 3.205 (CI 1.105-9.299), p = 0.032]. CONCLUSION: Symptomatic improvement after pyloroplasty or G-POEM is independent of etiology of gastroparesis, GERD, and primary symptom. Response to dilation or Botox are not markers of response to surgery. However, patients who receive Botox are 3.2 times more likely to improve postoperatively.

Impact of Objective Colonic and Whole Gut Motility Data as Measured by Wireless Motility Capsule on Outcomes of Antireflux Surgery.

BACKGROUND: Studies show higher rates of dissatisfaction with antireflux surgery (ARS) outcomes in patients with chronic constipation. This suggests a relationship between colonic dysmotility and suboptimal surgical outcome. However, due to limitations in technology, there is no objective data available examining this relationship. The wireless motility capsule (WMC) is a novel technology consisting of an ingestible capsule equipped with pH, temperature, and pressure sensors, which provide information regarding regional and whole gut transit times, pH and motility. The aim of this study was to assess the impact of objective regional and whole gut motility data on the outcomes of ARS. STUDY DESIGN: This was a retrospective review of patients who underwent WMC testing before ARS. Transit times, motility, and pH data obtained from different gastrointestinal tract regions were used in analysis to determine factors that impact surgical outcome. A favorable outcome was defined as complete resolution of the predominant reflux symptom and freedom from antisecretory medications. RESULTS: The final study population consisted of 48 patients (fundoplication [n = 29] and magnetic sphincter augmentation [n = 19]). Of those patients, 87.5% were females and the mean age ± SD was 51.8 ± 14.5 years. At follow-up (mean ± SD, 16.8 ± 13.2 months), 87.5% of all patients achieved favorable outcomes. Patients with unfavorable outcomes had longer mean whole gut transit times (92.0 hours vs 55.7 hours; p = 0.024) and colonic transit times (78.6 hours vs 47.3 hours; p = 0.028), higher mean peak colonic pH (8.8 vs 8.15; p = 0.009), and higher mean antral motility indexes (310 vs 90.1; p = 0.050). CONCLUSIONS: This is the first study to demonstrate that objective colonic dysmotility leads to suboptimal outcomes after ARS. WMC testing can assist with preoperative risk assessment and counseling for patients seeking ARS.

Magnetic sphincter augmentation and high-resolution manometry: impact of biomechanical properties on esophageal motility and clinical significance for selection and outcomes.

Magnetic sphincter augmentation (MSA)was introduced as an alternative to laparoscopic Nissen fundoplication (LNF). This reproducible, outpatient procedure addresses the etiology of gastroesophageal reflux disease by implanting a ring of magnetic beads across the esophagogastric junction (EGJ). MSA is designed to resist effacement of the lower esophageal sphincter (LES) and, similar to LNF, results in restoration of anti-reflux barrier competency by increasing overall length, intraabdominal length and resting pressure of the sphincter. However, the novel use of magnets to augment the physiology of the LES poses unique challenges to the physiology of the EGJ and esophagus. These impacts are best revealed through manometry. The degree of restrictive forces at the EGJ, as measured by intrabolus pressure and integrated relaxation pressure, is higher after MSA compared with LNF. In addition, contrary to the LNF, which retains neurohormonal relaxation capability during deglutition, the magnetic forces remain constant until forcibly opened. Therefore, the burden of overcoming EJG resistance is placed solely on the esophageal body contractile force, as measured by distal contractile integral and distal esophageal amplitude. The main utility of preoperative manometry is in determining whether a patient's esophagus has sufficient contractility or peristaltic reserve to adapt to the challenge of an MSA. Manometric thresholds predictive of MSA outcomes deviate from those used to define named Chicago Classification motility disorders. Therefore, individual preoperative manometric characteristics should be analyzed to aid in risk stratification and patient selection prior to MSA.

GERD after Peroral Endoscopic Myotomy: Assessment of Incidence and Predisposing Factors.

BACKGROUND: Peroral endoscopic myotomy (POEM) is an effective intervention for achalasia, but GERD is a major postoperative adverse event. This study aimed to characterize post-POEM GERD and identify preoperative or technical factors impacting development or severity of GERD. STUDY DESIGN: This is a retrospective review of patients who underwent POEM at our institution. Favorable outcome was defined as postoperative Eckardt score of 3 or less. Subjective GERD was defined as symptoms consistent with reflux. Objective GERD was based on a DeMeester score greater than 14.7 or Los Angeles grade C or D esophagitis. Severe GERD was defined as a DeMeester score greater than 50.0 or Los Angeles grade D esophagitis Preoperative clinical and objective data and technical surgical elements were compared between those with and without GERD. Multivariate logistic analysis was performed to identify factors associated with each GERD definition. RESULTS: A total of 183 patients underwent POEM. At a mean ± SD follow-up of 21.7 ± 20.7 months, 93.4% achieved favorable outcome. Subjective, objective, and severe objective GERD were found in 38.8%, 50.5%, and 19.2% of patients, respectively. Of those with objective GERD, 24.0% had no reflux symptoms. Women were more likely to report GERD symptoms (p = 0.007), but objective GERD rates were similar between sexes (p = 0.606). The independent predictors for objective GERD were normal preoperative diameter of esophagus (odds ratio [OR] 3.4; p = 0.008) and lower esophageal sphincter (LES) pressure less than 45 mmHg (OR 1.86; p = 0.027). The independent predictors for severe objective GERD were LES pressure less than 45 mmHg (OR 6.57; p = 0.007) and obesity (OR 5.03; p = 0.005). The length of esophageal or gastric myotomy or indication of procedure had no impact on the incidence or severity of GERD. CONCLUSION: The rate of pathologic GERD after POEM is higher than symptomatic GERD. A nonhypertensive preoperative LES is a predictor for post-POEM GERD. No modifiable factors impact GERD after POEM.

Long-term clinical and functional results of magnetic sphincter augmentation.

Magnetic sphincter augmentation (MSA) was introduced in 2007 as an alternative surgical procedure for patients with gastroesophageal reflux disease (GERD). The majority of data since MSA's introduction has focused on short and intermediate-term results, demonstrating safety and high efficacy in terms of reflux symptom control, freedom from proton pump inhibitor use and normalization of distal esophageal acid exposure. However, GERD is a chronic condition that demands a long-term solution. Limited available data from studies reporting outcomes at 5 years or later following MSA demonstrate that the promising short- and mid-term efficacy and safety profile of MSA remains relatively constant in the long term. Compared with Nissen fundoplication, MSA has a much lower rate of gas-bloat and inability to belch at a short-term follow-up, a difference that persists in the long-term. The most common complaint after MSA at a short-term follow-up is dysphagia. However, limited data suggest dysphagia rates largely decrease by 5 years. Dysphagia is the most common indication for dilation and device removal in both early- and long-term studies. However, the overall rates of dilation and removal are similar in short- and long-term reports, suggesting the majority of these procedures are performed in the short-term period after device implantation. The indications and standard practices of MSA have evolved over time. Long-term outcome data currently available are all from patient cohorts who were selected for MSA under early restricted indications and outdated regimens. Therefore, further long-term studies are needed to corroborate the preliminary, yet encouraging long-term results.

Experimental Modal Analysis of an In-situ Clavicle.

Clavicle fractures are widespread, and the understanding of their mechanism of occurrence via dynamic loading is important for prevention and design of protection systems. The proposed work will find the natural frequencies and mode shapes of the human clavicles in-situ, by employing experimental modal analysis (EMA) techniques on cadaver clavicles. The clavicle response to impact depends on mechanical energy transmission to the bone and requires an understanding of bone modal characteristics (natural frequencies and mode shapes), as well as the frequency content of the impact force. These dynamic forces include blunt trauma (sport injury or gun stock impact) or falls (i.e. motorcycle accidents) and exhibit a wide frequency spectrum. Clavicle modes are not well understood, and while researchers performed whole body or individual clavicle EMA, no in-situ EMA has been reported. Since an in-situ clavicle features its natural boundary conditions, mode estimation via EMA was more accurate than one performed for an isolated clavicle.The clavicle EMA used instrumented excitation sources (i.e. impact hammer) and sensors (i.e. triaxial accelerometers). The accelerometer responses gathered at several locations along the cadaver clavicle bone and the exciting force was recorded and through time-frequency transformations, the natural frequencies and mode shapes were identified. Mode shape visualization was performed in ModalView software. While material properties of cadaver clavicles may be influenced by embalming, the results, which include natural frequencies, modes and damping constants, would be more relevant than those obtained for isolated clavicles. These results would be used to design protection systems, define global material properties, and calibrate existing analytical models.

EVIDENCE-BASED CURRICULAR CONTENT IMPROVES STUDENT KNOWLEDGE AND CHANGES ATTITUDES TOWARDS TRANSGENDER MEDICINE.

OBJECTIVE: Previous studies have demonstrated that the addition of transgender medicine content to a medical school curriculum increased students' comfort and willingness to treat transgender patients. We aimed to demonstrate that (1) evidence-based curricular content would improve knowledge of and change attitudes towards transgender medicine, and (2) students would consider cross-sex hormone therapy a legitimate treatment option for transgender patients. METHODS: Curricular content with a focus on the biologic evidence for the durability of gender identity was added to the first-year medical program at Boston University School of Medicine. Immediately before and after exposure to the content, students were presented with an assessment of their knowledge of the etiology of gender identity. RESULTS: Immediately following exposure to the content, a significant number of students changed their answer regarding the etiology of gender identity so that the number of correct responses increased from 63% (n = 56) to 93% (n = 121) (P<.001). For transgender treatment, the number of correct responses increased from 20% (n = 56) before exposure to the content to 50% (n = 121) following exposure (P<.001). CONCLUSION: The addition of transgender medicine content to a medical school curriculum with a focus on the biologic evidence for a durable gender identity is an effective means of educating students about the etiology of gender identity and the appropriateness of cross-sex hormone therapy as a treatment for transgender patients.