Assessment of biomechanical behavior of immature non-vital incisors with various treatment modalities by means of three-dimensional quasi-static finite element analysis.

The objectives of this study were to evaluate the stress distribution and risk of fracture of a non-vital immature maxillary central incisor subjected to various clinical procedures using finite element analysis (FEA). A three-dimensional model of an immature central incisor was developed, from which six main models were designed: untreated immature tooth (C), standard apical plug (AP), resin composite (RC), glass-fibre post (GFP), regeneration procedure (RET), and regeneration with induced root maturation (RRM). Mineral trioxide aggregate (MTA) or Biodentine® were used as an apical or coronal plug. All models simulated masticatory forces in a quasi-static approach with an oblique force of 240 Newton at a 120° to the longitudinal tooth axis. The maximum principal stress, maximum shear stress, risk of fracture, and the strengthening percentage were evaluated. The mean maximum principal stress values were highest in model C [90.3 MPa (SD = 4.4)] and lowest in the GFP models treated with either MTA and Biodentine®; 64.1 (SD = 1.7) and 64.0 (SD = 1.6) MPa, respectively. Regarding the shear stress values, the dentine tooth structure in model C [14.4 MPa (SD = 0.8)] and GFP models [15.4 MPa (SD = 1.1)] reported significantly higher maximum shear stress values compared to other tested models (p < 0.001), while no significant differences were reported between the other models (p > 0.05). No significant differences between MTA and Biodentine® regarding maximum principal stress and maximum shear stress values for each tested model (p > 0.05). A maximum strain value of 4.07E-03 and maximum displacement magnitude of 0.128 mm was recorded in model C. In terms of strengthening percentage, the GFP models were associated with the highest increase (22%). The use of a GFP improved the biomechanical performance and resulted in a lower risk of fracture of a non-vital immature maxillary central incisor in a FEA model.

Distension contraction plots of pharyngeal/esophageal peristalsis: next frontier in the assessment of esophageal motor function.

Esophageal peristalsis consists of initial inhibition (relaxation) followed by excitation (contraction), both of which move sequentially in the aboral direction. Initial inhibition results in receptive relaxation and bolus-induced luminal distension, which allows propulsion by the contraction with minimal resistance to flow. Similar to the contraction wave, luminal distension has unique waveform characteristics in normal subjects; both are modulated by bolus volume, bolus viscosity, and posture, suggesting a possible cause-and-effect relationship between the two. Distension contraction plots in patients with dysphagia with normal bolus clearance [high-amplitude esophageal contractions (HAECs), esophagogastric junction outflow obstruction (EGJOO), and functional dysphagia (FD)] reveal two major findings: 1) unlike normal subjects, there is luminal occlusion distal to bolus during peristalsis in certain patients, i.e., with type 3 achalasia and nonobstructive dysphagia; and 2) bolus travels through a narrow lumen esophagus during peristalsis in patients with HAECs, EGJOO, and FD. Aforementioned findings indicate a relative dynamic obstruction to the bolus flow during peristalsis and reduced distensibility of esophageal wall in the bolus segment of the esophagus. We speculate that a normal or supernormal contraction wave pushing bolus against resistance is the mechanism of dysphagia sensation in significant number of patients. Representations of distension and contraction, combined with objective measures of flow timing and distensibility are complementary to the current scheme of classifying esophageal motility disorders based solely on the characteristics of contraction phase of peristalsis. Better understanding of the distensibility of the bolus-containing segment of the esophagus during peristalsis will lead to the development of novel medical and surgical therapies in the treatment of dysphagia in significant number of patients.

Quality of life assessment in esophageal atresia patients: a systematic review focusing on long-gap esophageal atresia.

BACKGROUND: Children born with esophageal atresia (EA) have inherent abnormalities in esophageal motility which may impact upon patient and family Quality of Life (QoL). Currently, paucity of data exists for long-term outcomes of long-gap EA. We aimed to: (1) summarize QoL tools reported in the literature, focusing upon studies involving long-gap EA patients, and (2) compare QoL for long-gap versus non-long-gap EA patients. METHOD: We performed a systematic review of Cochrane Register of Controlled Trials, PubMed, EMBASE, and Ovid databases (January 1980-May 2018) in accordance with the PRISMA protocol. RESULT: Six studies were identified (536 patients total), and 419/536 (78%) patients completed QoL assessment. Response rates ranged from 29% to 100%. Median study size was 86 (range 8-159). Esophageal atresia type was described in 477 patients, and 74/477 (16%) were long-gap. Common assessment tools were Gastrointestinal Quality of Life Index and 36-Item Short-Form Health Survey. Compared with healthy individuals, long-gap EA patients suffered more gastrointestinal symptoms. There were no significant differences in QoL outcomes between long-gap and non-long-gap EA patients. CONCLUSION: Current literature suggests no significant difference in QoL outcomes between long-gap and non-long-gap EA patients. However, due to questionnaire variability and range of response rates, the data should be interpreted with care. LEVEL OF EVIDENCE: Level II.

How to select patients for antireflux surgery? The ICARUS guidelines (international consensus regarding preoperative examinations and clinical characteristics assessment to select adult patients for antireflux surgery).

OBJECTIVE: Antireflux surgery can be proposed in patients with GORD, especially when proton pump inhibitor (PPI) use leads to incomplete symptom improvement. However, to date, international consensus guidelines on the clinical criteria and additional technical examinations used in patient selection for antireflux surgery are lacking. We aimed at generating key recommendations in the selection of patients for antireflux surgery. DESIGN: We included 35 international experts (gastroenterologists, surgeons and physiologists) in a Delphi process and developed 37 statements that were revised by the Consensus Group, to start the Delphi process. Three voting rounds followed where each statement was presented with the evidence summary. The panel indicated the degree of agreement for the statement. When 80% of the Consensus Group agreed (A+/A) with a statement, this was defined as consensus. All votes were mutually anonymous. RESULTS: Patients with heartburn with a satisfactory response to PPIs, patients with a hiatal hernia (HH), patients with oesophagitis Los Angeles (LA) grade B or higher and patients with Barrett's oesophagus are good candidates for antireflux surgery. An endoscopy prior to antireflux surgery is mandatory and a barium swallow should be performed in patients with suspicion of a HH or short oesophagus. Oesophageal manometry is mandatory to rule out major motility disorders. Finally, oesophageal pH (±impedance) monitoring of PPI is mandatory to select patients for antireflux surgery, if endoscopy is negative for unequivocal reflux oesophagitis. CONCLUSION: With the ICARUS guidelines, we generated key recommendations for selection of patients for antireflux surgery.

Piecemeal Deglutition and the Implications for Pressure Impedance Dysphagia Assessment in Pediatrics.

OBJECTIVES: High-resolution impedance manometry (HRIM) enables biomechanical swallow assessment. Piecemeal deglutition (PD) defines swallowing of a single bolus in 2 or more portions. We investigated PD sequences on HRIM recordings to ascertain appropriate swallow selection for analysis and to determine the impact of PD on swallow function measures. METHODS: Pharyngo-esophageal motility and bolus flow were assessed in 27 children (19 M, mean age 15 months) with repaired esophageal atresia and trachea-esophageal fistula, but who were asymptomatic of oropharyngeal dysphagia. A consistent volume of between 2 and 5 mL saline boluses was given to each patient. Retrospectively, PD sequences were defined based on the number of swallows required to clear the bolus from the oral cavity: pattern A = 1-2 swallows; pattern B = 3 swallows; and pattern C = 4+ swallows. The largest bolus volume swallowed was noted as the dominant swallow in each pattern. Pressure Flow Analysis defined contractility, distension and flow timing metrics. Data were averaged for each PD pattern, and compared with dominant swallows from each pattern. RESULTS: PD pattern B (43.7%) was the most prevalent across the cohort. PD patterns were similarly distributed across age groups (G1: <1 years, G2: 1-4 years). Differences in upper esophageal sphincter distension and pharyngeal flow timing measures were, however, seen in relation to both age and PD pattern, whereby a larger pharynx in older children elicited greater distension for a longer latency, and for larger volumes. CONCLUSIONS: PD reduces bolus volume, and biomechanical swallow measures are impacted. PD is a necessary consideration for accurate HRIM analysis of swallow function. Selection of dominant swallows from a PD sequence provides a swallow profile which best represents a child's swallow function, and should always be reported and interpreted in context of the PD sequence observed.

Pressure-Flow Analysis for the Assessment of Pediatric Oropharyngeal Dysphagia.

OBJECTIVES: To determine which objective pressure-impedance measures of pharyngeal swallowing function correlated with clinically assessed severity of oropharyngeal dysphagia (OPD) symptoms. STUDY DESIGN: Forty-five children with OPD and 34 control children without OPD were recruited and up to 5 liquid bolus swallows were recorded with a solid-state high-resolution manometry with impedance catheter. Individual measures of pharyngeal and upper esophageal sphincter (UES) function and a swallow risk index composite score were derived for each swallow, and averaged data for patients with OPD were compared with those of control children without OPD. Clinical severity of OPD symptoms and oral feeding competency was based on the validated Dysphagia Disorders Survey and Functional Oral Intake Scale. RESULTS: Those objective measures that were markers of UES relaxation, UES opening, and pharyngeal flow resistance differentiated patients with and without OPD symptoms. Patients demonstrating abnormally high pharyngeal intrabolus pressures and high UES resistance, markers of outflow obstruction, were most likely to have signs and symptoms of overt Dysphagia Disorders Survey (OR 9.24, P = .05, and 9.7, P = .016, respectively). CONCLUSION: Pharyngeal motor patterns can be recorded in children by the use of HRIM and pharyngeal function can be defined objectively with the use of pressure-impedance measures. Objective measurements suggest that pharyngeal dysfunction is common in children with clinical signs of OPD. A key finding of this study was evidence of markers of restricted UES opening.

Pressure flow analysis in the assessment of preswallow pharyngeal bolus presence in Dysphagia.

Objectives. Preswallow pharyngeal bolus presence is evident in patients with oropharyngeal dysphagia. Pressure flow analysis (PFA) using high resolution manometry with impedance (HRMI) with AIMplot software is a method for objective interpretation of pharyngeal and upper esophageal sphincter (UES) pressures and bolus flow patterns during swallowing. This study aimed to observe alterations in PFA metrics in the event of preswallow pharyngeal bolus presence as seen on videofluoroscopy (VFSS). Methods. Swallows from 40 broad dysphagia patients and 8 controls were recorded with a HRMI catheter during simultaneous VFSS. Evidence of bolus presence and level reached prior to pharyngeal swallow onset was recorded. AIMPlot software derived automated PFA functional metrics. Results. Patients with bolus movement to the pyriform sinuses had a higher SRI, indicating greater swallow dysfunction. Amongst individual metrics, TNadImp to PeakP was shorter and flow interval longer in patient groups compared to controls. A higher pharyngeal mean impedance and UES mean impedance differentiated the two patient groups. Conclusions. This pilot study identifies specific altered PFA metrics in patients demonstrating preswallow pharyngeal bolus presence to the pyriform sinuses. PFA metrics may be used to guide diagnosis and treatment of patients with oropharyngeal dysphagia and track changes in swallow function over time.

Objective assessment of swallow function in children with suspected aspiration using pharyngeal automated impedance manometry.

OBJECTIVES: The purpose of the present study was to apply a new method, pharyngeal automated impedance manometry (AIM), as an objective assessment tool of swallow function relevant to aspiration, in a cohort of paediatric patients with dysphagia. METHODS: We studied 20 children (mean age 6 years [5 months to 13.4 years]) referred for videofluoroscopy to assess aspiration risk with simultaneous manometry-impedance. Fluoroscopic evidence of aspiration was scored using a validated aspiration-penetration score. Pressure-flow profiles were analysed using AIM analysis measuring peak pressure, pressure at nadir impedance, time from nadir impedance to peak pressure, and flow interval. These variables were combined into a swallow risk index (SRI). RESULTS: Six of 20 children presented with deglutitive aspiration during videofluoroscopic assessment of swallowing. Of 58 liquid swallows analysed, in 9 aspiration was observed. Multiple logistic regression identified longer flow interval (P < 0.05), higher SRI (P < 0.05) and increased pressure in the upper oesophageal sphincter during maximal bolus flow (P < 0.05) to be the dominant risk variables predictive of aspiration in children. Each of these nonradiologically derived pressure-flow variables correlated with higher aspiration scores on videofluoroscopy (P < 0.01). CONCLUSIONS: We present novel, preliminary findings in children with deglutitive aspiration, suggesting that pharyngeal AIM can detect alterations in pressure-flow characteristics of swallowing that predispose to aspiration risk.

A novel method for the nonradiological assessment of ineffective swallowing.

OBJECTIVES: This validation study evaluates a new manometry impedance-based approach for the objective assessment of pharyngeal function relevant to postswallow bolus residue. METHODS: We studied 23 adult and pediatric dysphagic patients who were all referred for a videofluoroscopy, and compared these patients with 10 adult controls. The pharyngeal phase of swallowing of semisolid boluses was recorded with manometry and impedance. Fluoroscopic evidence of postswallow bolus residue was scored. Pharyngeal pressure impedance profiles were analyzed. Computational algorithms measured peak pressure (Peak P), pressure at nadir impedance (PNadImp), time from nadir impedance to PeakP (PNadImp-PeakP), the duration of impedance drop in the distal pharynx (flow interval), upper esophaghageal sphincter (UES) relaxation interval (UES-RI), nadir UES pressure (NadUESP), UES intrabolus pressure (UES-IBP), and UES resistance. A swallow risk index (SRI) was derived by the formula: SRI=(FI × PNadImp)/(PeakP × (TNadImp-PeakP+1)) × 100. RESULTS: In all, 76 patient swallows (35 with residue) and 39 control swallows (12 with residue) were analyzed. Different functional variables were found to be altered in relation to residue. In both controls and patients, flow interval was longer in relation to residue. In controls, but not patients, residue was associated with an increased PNadImp (suggestive of increased pharyngeal IBP). Controls with residue had increased UES-IBP, NadUESP, and UES resistance compared with patients with residue. Residue in patients was related to a prolonged UES-RI. The SRI was elevated in relation to residue in both controls and patients and an average SRI of 9 was optimally predictive of residue (sensitivity 75% and specificity 80%). CONCLUSIONS: We present novel findings in control subjects and dysphagic patients showing that combined manometry and impedance recordings can be objectively analyzed to derive pressure-flow variables that are altered in relation to the bolus residual and can be combined to predict ineffective pharyngeal swallowing.

Assessment of intraluminal impedance for the detection of pharyngeal bolus flow during swallowing in healthy adults.

Intraluminal impedance, a nonradiological method for assessing bolus flow within the gut, may be suitable for investigating pharyngeal disorders. This study evaluated an impedance technique for the detection of pharyngeal bolus flow during swallowing. Patterns of pharyngoesophageal pressure and impedance were simultaneously recorded with videofluoroscopy in 10 healthy volunteers during swallowing of liquid, semisolid, and solid boluses. The timing of bolus head and tail passage recorded by fluoroscopy was correlated with the timing of impedance drop and recovery at each recording site. Bolus swallowing produced a drop in impedance from baseline followed by a recovery to at least 50% of baseline. The timing of the pharyngeal and esophageal impedance drop correlated with the timing of the arrival of the bolus head. In the pharynx, the timing of impedance recovery was delayed relative to the timing of clearance of the bolus tail. In contrast, in the upper esophageal sphincter (UES) and proximal esophagus, the timing of impedance recovery correlated well with the timing of clearance of the bolus tail. Impedance-based estimates of pharyngoesophageal bolus clearance time correlated with true pharyngoesophageal bolus clearance time. Patterns of intraluminal impedance recorded in the pharynx during bolus swallowing are therefore more complex than those in the esophagus. During swallowing, mucosal contact between the tongue base and posterior pharyngeal wall prolongs the duration of pharyngeal impedance drop, leading to overestimation of bolus tail timing. Therefore, we conclude that intraluminal impedance measurement does not accurately reflect the bolus transit in the pharynx but does accurately reflect bolus transit across the UES and below.

Is the correction factor used in the breath test assessment of gastric emptying appropriate for use in infants?

OBJECTIVES: The gastric emptying breath test (GEBT) is now routinely used in many centers. Validation studies in adults have shown that although there is a linear correlation between the GEBT and scintigraphy, the GEBT overestimates gastric half emptying time (GEt1/2) by a constant of approximately 60 minutes because of postgastric processing. It is therefore conventional to apply a "correction factor" to the GEBT result. Because = no similar validation studies have been performed in infants, the aim of this study was to directly characterize the postgastric processing of 13C octanoic acid in infants to assess the suitability of the standard correction factor for use in infants. METHODS: The pattern of breath 13CO2 excretion after separate infusion of 13C octanoic acid into either the stomach or the duodenum was measured in 13 healthy preterm infants (6 male, 7 female). The raw 13CO2 half excretion time after intragastric (GEt1/2 raw) and intraduodenal (DEt1/2 raw) administration of C octanoic acid was calculated, and the difference between GEt1/2 raw and DEt1/2 raw (i.e., GEt1/2 raw - DEt1/2 raw) was directly compared with GEt1/2 corrected, derived by applying the standard correction factor to GEt1/2 raw. RESULTS: Values for GEt1/2 raw - DEt1/2 raw correlated significantly with GEt1/2 corrected. CONCLUSION: Our results show that the standard correction factor is appropriate for performing the GEBT in preterm infants.