Pathophysiology of swallowing following oropharyngeal surgery for obstructive sleep apnea syndrome

Corticosteroid Effects on Upper Esophageal Sphincter Function in Anterior Cervical Discectomy and Fusion: A Study Using High-Resolution Impedance Manometry

BACKGROUND

The aim of our study was to explore the effect of local corticosteroids on dysphagia in patients undergoing anterior cervical discectomy and fusion (ACDF). To address a gap in the limited research on this topic, we utilized high-resolution impedance manometry (HRIM) and the Eating Assessment Tool-10 (EAT-10) questionnaire to assess the effects on key swallowing muscles, including the upper esophageal sphincter (UES).

METHODS

We randomly assigned patients undergoing ACDF to either the corticosteroid group or the saline solution group. Patients received 10 mg of local triamcinolone or saline solution prevertebrally at the cervical spine level before wound closure. Swallowing function preoperatively and at 1 month postoperatively were compared between the groups with use of HRIM parameters (e.g., UES relaxation, UES opening extent, intrabolus pressure, and pharyngeal contraction) and EAT-10 scores. Patients were also followed for postoperative complications and mortality within 12 months after surgery.

RESULTS

Thirty patients completed the study. The median age was 55 years in the corticosteroid group and 57 years in the saline group, and each group had 8 female patients. All participants were Taiwanese. We found no significant difference in median preoperative UES relaxation pressure between the corticosteroid and saline solution groups (33.8 and 31.3 mm Hg, respectively; p = 0.54). Postoperatively, the corticosteroid group had significantly lower median UES relaxation pressure than the saline solution group (24.5 versus 33.6 mm Hg; p = 0.01). Before and after surgery, all other HRIM parameters and EAT-10 scores were similar between the groups, with the corticosteroid group demonstrating median pre- and postoperative EAT-10 scores of 0 and 4, respectively, and the saline solution group demonstrating scores of 2 and 3, respectively. There were no adverse events.

CONCLUSIONS

The findings suggest that local corticosteroids may reduce UES relaxation pressure at 1 month after ACDF, potentially enhancing UES opening. Further research is required to verify our findings.

LEVEL OF EVIDENCE

Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Complications and side effects after barbed pharyngoplasty: a systematic review

BACKGROUND

Recently, the use of barbed pharyngoplasty (BP) has become widespread in snoring and obstructive sleep apnoea (OSA) palatal surgery, but there are no studies regarding the short- and long-term complications resulting from these different techniques. This systematic review aimed to report the complications and side effects of different BP techniques.

METHODS

An electronic search was performed on PubMed/MEDLINE, Google Scholar, and Ovid databases. The PRISMA statement was followed. Databases were searched from inception through September 2, 2021.

RESULTS

We included 14 prospective clinical studies consisting of 769 patients aged 23 to 81 years. The associated intra-operative complications of BP were as follows: partial thread extrusion (2.9%), self-limited bleeding (2.9%), broken needle (1.0%), and suture rupture (1.0%). Short-term complications were as follows: thread/knot extrusion (12.4%), dysphagia (5.6%), bleeding (1.5%), velopharyngeal insufficiency (1.5%), anterior pharyngoplasty dehiscence (1.2%), tonsillar haemorrhage (1.0%), excessive postnasal discharge (1.0%), barbed suture failure (0.5%), acute infection (0.2%), mucosal granulomas (0.2%), chipped tooth caused by mouth gag displacement (0.2%), and fibrous scar (0.2%). Long-term complications were as follows: foreign body sensation (7.8%), sticky mucus in throat (5.9%), dysphagia (3.6%), rhinolalia (3.1%), throat phlegm (1.1%), nose regurgitation (0.8%), dry throat (0.6%), and throat lump (0.3%).

CONCLUSION

BP is a safe technique free of significant side effects and major complications. However, in this review, patients undergoing BP were very heterogeneous in terms of characteristics of patients chosen and severity of diseases, surgical technique used (myoresective vs non-myoresective), time of follow-up, and mono level vs multilevel surgery. More studies on a larger scale with long-term follow-up are needed to confirm these promising results.

Functional Outcomes of Swallowing Following Surgery for Obstructive Sleep Apnea

OBJECTIVE

Identification and evaluation of swallowing dysfunction in patients undergoing upper airway surgery for obstructive sleep apnea (OSA) is limited. This study evaluated subjective swallowing function pre and postoperatively in patients undergoing multi-level reconstructive pharyngeal sleep surgery.

METHODS

A retrospective analysis of prospectively-administered Eating Assessment Tool (EAT-10) scores was conducted among adult patients undergoing surgery for OSA at a tertiary sleep surgery center. Preoperative and 1, 3, and 6-month postoperative time points were assessed. Patients were subdivided into two groups based on the degree of upper airway reconstruction performed. All patients underwent uvulopalatopharyngoplasty +/-tonsillectomy and tongue-base reduction. Patients undergoing Phase 1 reconstructive surgery additionally underwent tongue-base advancement procedures.

RESULTS

A total 100 patients underwent airway reconstructive surgery. Forty-one patients underwent Phase 1 surgery; 59 patients underwent Mini-Phase 1 surgery. Neither group demonstrated preoperative dysphagia. Both groups experienced significant subjective dysphagia at 1-month postoperatively, which was greater among Phase 1 patients (mean EAT-10 14.8; SD 10.4) versus Mini-Phase 1 patients (mean EAT-10 6.7; SD 7.5) (p < 0.001). Swallowing function among both groups normalized by 3 and 6 months postoperatively. Phase 1 patients with pre-operative dysphagia (mean EAT-10 9.6; SD 5) demonstrated initial worsening of their swallowing postoperatively; however, reported improved swallowing versus pre-operative levels by 6 months postoperatively (mean EAT-10 3.6; SD 4.3) (p = 0.03).

CONCLUSION

Pharyngeal surgery resulted in no significant, persistent adverse change in swallowing function. Among both groups, significant subjective dysphagia was reported at 1 month postoperatively, yet returned to preoperative levels by 6 months postoperatively. OSA patients with pre-existing dysphagia undergoing Phase 1 surgery trended towards improved swallowing function postoperatively.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:199-204, 2023.

Swallowing biomechanics before and following multi-level upper airway surgery for obstructive sleep apnea

STUDY OBJECTIVES

The effect of contemporary multi-level upper airway surgery for obstructive sleep apnea on swallowing is unclear. This study assessed the biomechanical swallowing function in participants with obstructive sleep apnea pre- and post-modified uvulopalatopharyngoplasty and coblation channeling of the tongue.

METHODS

In this prospective, longitudinal study, adults diagnosed with moderate-severe obstructive sleep apnea who underwent modified uvulopalatopharyngoplasty and coblation channeling of the tongue surgery had swallowing biomechanics assessed using high-resolution pharyngeal manometry and analyzed with swallowgateway.com. Symptomatic swallowing difficulty was evaluated using the Sydney Swallow Questionnaire (≥ 234). General linear mixed-model analysis was conducted to evaluate the difference pre- and post-modified uvulopalatopharyngoplasty and coblation channeling of the tongue. Data are presented as mean [95% confidence intervals].

RESULTS

High-resolution pharyngeal manometry assessments were conducted in 10 participants (7 men; median age 50 [interquartile range 36-65]) preoperatively and repeated postoperatively at 9 months [interquartile range 6-13]. Self-reported dysphagia was unchanged following surgery (Sydney Swallow Questionnaire =149 [53, 447] to 168 [54, 247]; P = .093). High-resolution pharyngeal manometry outcomes indicated reduced mesopharyngeal pressures (148 [135, 161] to 124 [112, 137] mm Hg s cm; P = .011), reduced hypopharyngeal pressures (113 [101, 125] to 93 [84, 102] mm Hg s cm; P = 0.011), and reduced upper esophageal sphincter relaxation pressure (5 [4, 6] to 2 [1,3] mm Hg; P = 0.001) but no change to velopharyngeal pressures (135 [123, 147] to 137 [117, 157] mm Hg s cm; P = .850) postsurgery.

CONCLUSIONS

Modified uvulopalatopharyngoplasty may have less implications on the swallow mechanism than previously suspected. In contrast, the reduction in mesopharyngeal contractile pressures associated with coblation channeling of the tongue, although within normal limits, may affect bolus propulsion. Biomechanical alterations were insufficient to worsen self-reported swallowing function.

CITATION

Schar MS, Omari TI, Woods CW, et al. Swallowing biomechanics before and following multi-level upper airway surgery for obstructive sleep apnea. J Clin Sleep Med. 2022;18(4):1167-1176.

Variables influencing manometric parameters of deglutitive and non-deglutitive upper esophageal sphincter: A study of 89 asymptomatic participants

BACKGROUND

High-resolution manometry overcomes limitations imposed by axial and radial asymmetry as well as swallow and respiration-induced movement of the upper esophageal sphincter (UES), allowing for its reliable use in evaluation of dysphagic and reflux patients. The aim of this study was to determine normative values and their variability across position, sex, age, height, weight, BMI, and volume for clinically relevant deglutitive and non-deglutitive UES parameters.

METHODS

We studied 89 asymptomatic volunteers age 19-90 years, (45 female) during 3-10 repetitions of dry, 5 and 10 ml water swallows at 30-s intervals using high-resolution manometry.

KEY RESULTS

Upper esophageal sphincter high-pressure zone was longer in men than women and in supine than upright position. UES basal contractile integral and mean basal pressure were higher in supine compared to upright; higher in men than women, inversely correlated with age, correlated positively with height and with weight in the supine position only. UES relaxation duration was longer in upright than in supine position but not affected by age, sex, height, weight, or BMI. It was longer with 5 and 10 ml compared with dry swallows. UES minimum/nadir relaxation and mean relaxation pressures were lower in upright than supine position, increased with increase in age and were higher in men than women.

CONCLUSIONS AND INFERENCES

Position, sex, age, height, weight, and volume affect some deglutitive and non-deglutitve UES manometric parameters. BMI does not affect the studied manometric parameters. These effects should be taken into consideration in clinical evaluation of UES.

Effect of Topical Nasal Anesthetic on Comfort and Swallowing in High-Resolution Impedance Manometry

OBJECTIVES/HYPOTHESIS

Use of topical nasal anesthetic (TNA) is common in high-resolution impedance manometry (HRIM). This study investigated the effect of TNA on swallowing and procedure tolerability during HRIM with a 4.2-mm catheter, a more commonly used catheter size with impedance capabilities.

STUDY DESIGN

Randomised experimental study with blinding of participants.

METHODS

Twenty healthy participants (mean age = 33 years, 16 female) were randomized to undergo HRIM using the ManoScan™ ESO Z 4.2-mm catheter twice, 1 week apart, under two conditions: with TNA (viscous lidocaine) and with placebo. Analyses included esophageal data of three saliva, three saline (5 mL), and three bread swallows (2 cm × 2 cm) performed while reclined 45°, and pharyngeal data under the same conditions while seated upright. Pharyngeal and upper esophageal sphincter (UES) HRIM parameters were analyzed using the Swallow Gateway analysis platform. Visual analogue scale (VAS) scores rating procedural comfort were analyzed.

RESULTS

There were no significant physiological differences in pharyngeal and UES parameters between conditions. There were also no significant differences in VAS scores under placebo (mean = 54.8, standard deviation (SD) = 19.3) and TNA (mean = 60.0, SD = 21.9) (t[19] = -0.9, P = .4) conditions; however, there was a significant difference in the first versus second session (t[19]) = 5.1, P < .05).

CONCLUSIONS

TNA did not improve comfort, but it also did not significantly affect swallowing behavior. There was, however, a practice effect regardless of TNA use with improved tolerance of the 4.2-mm catheter and likely more natural swallowing behavior during the second session of HRIM.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Pharyngo-Esophageal Modulatory Swallow Responses to Bolus Volume and Viscosity Across Time

Objectives/Hypothesis

Modulation of the pharyngeal swallow to bolus volume and viscosity is important for safe swallowing and is commonly studied using high‐resolution pharyngeal manometry (HRPM). Use of unidirectional pressure sensor technology may, however, introduce variability in swallow measures and a fixed bolus administration protocol may induce time and order effects. We aimed to overcome these limitations and to investigate the effect of time by repeating randomized measurements using circumferential pressure sensor technology.

Study Design

Sub‐set analysis of data from the placebo arm of a randomized, repeated measures trial.

Methods

HRPM with impedance was recorded using a solid‐state catheter with 36 circumferential pressure sensors and 18 impedance segments straddling from hypopharynx to stomach. Testing included triplicates of 5, 10, and 20 ml thin liquid and 10 ml thick liquid boluses, the order of the thin liquid boluses was randomized. The swallow challenges were repeated approximately 10 minutes after finishing the baseline measurement.

Results

We included 19 healthy adults (10/9 male/female; age 24.5 ± 4.1 year). Intrabolus pressure, all upper esophageal sphincter (UES) opening and relaxation metrics, and flow timing metrics increased with larger volumes. A thicker viscosity decreased UES relaxation time, UES basal pressure, and flow timing metrics, whereas UES opening extent increased. Pre‐swallow UES basal pressure and post‐swallow UES contractile integral decreased over time.

Conclusion

Using circumferential pressure sensor technology, the effects of volume and viscosity were largely consistent with previous reports. UES contractile pressures reduced over time. The growing body of literature offers a benchmark for recognizing aberrant pharyngo‐esophageal motor responses.

Level of Evidence

3 Laryngoscope, 132:1817–1824, 2022

Altered swallowing biomechanics in people with moderate-severe obstructive sleep apnea

STUDY OBJECTIVES

Dysphagia is a common but under-recognized complication of obstructive sleep apnea (OSA). However, the mechanisms remain poorly described. Accordingly, the aim of this study was to assess swallowing symptoms and use high-resolution pharyngeal manometry (HRPM) to quantify swallowing biomechanics in patients with moderate-severe OSA.

METHODS

Nineteen adults (4 female, mean age 46±26-68y) with moderate-severe OSA underwent HRPM testing with 5,10 & 20 ml volumes of thin and extremely thick liquids. Data were compared to 19 age- and sex-matched healthy controls (mean age 46±27-68y). Symptomatic dysphagia was assessed using the Sydney Swallow Questionnaire (SSQ). Swallow metrics were analyzed using the online application swallowgateway.com. General linear mixed model analysis was performed to investigate potential differences between people with moderate-severe OSA and controls. Data presented are means (95% CI).

RESULTS

26% (5/19) of the OSA group but none of the controls reported symptomatic dysphagia (SSQ>234). Compared to healthy controls, the OSA group had increased upper esophageal sphincter (UES) relaxation pressure (-2 [-1] vs. 2 [1]mmHg, F = 32.1, p <0.0001), reduced UES opening (6 vs. 5mS, F = 23.6, p<0.0001) and increased hypopharyngeal intrabolus pressure (2 [1] vs 7 [1]mmHg, F= 19.0, p <0.05). Additionally, upper pharyngeal pressures were higher, particularly at the velopharynx (88 [12] vs. 144 [12]mmHg.cm.s, F = 69.6, p<0.0001).

CONCLUSIONS

HRPM identified altered swallowing biomechanics in people with moderate-severe OSA, which is consistent with a subclinical presentation. Potential contributing mechanisms include UES dysfunction with associated upstream changes of increased hypopharyngeal distension pressure and velopharyngeal contractility.

Modulation of pharyngeal swallowing by bolus volume and viscosity

Oropharyngeal swallowing involves complex neuromodulation to accommodate changing bolus characteristics. The pressure events during deglutitive pharyngeal reconfiguration and bolus flow can be assessed quantitatively using high-resolution pharyngeal manometry with impedance. An 8-French solid-state unidirectional catheter (32 pressure sensors, 16 impedance segments) was used to acquire triplicate swallows of 3 to 20 ml across three viscosity levels using a Standardized Bolus Medium (SBMkit) product (Trisco, Pty. Ltd., Australia). An online platform (https://swallowgateway.com/; Flinders University, South Australia) was used to semiautomate swallow analysis. Fifty healthy adults (29 females, 21 males; mean age 46 yr; age range 19-78 yr old) were studied. Hypopharyngeal intrabolus pressure, upper esophageal sphincter (UES) maximum admittance, UES relaxation pressure, and UES relaxation time revealed the most significant modulation effects to bolus volume and viscosity. Pharyngeal contractility and UES postswallow pressures elevated as bolus volumes increased. Bolus viscosity augmented UES preopening pressure only. We describe the swallow modulatory effects with quantitative methods in line with a core outcome set of metrics and a unified analysis system for broad reference that contributes to diagnostic frameworks for oropharyngeal dysphagia.NEW & NOTEWORTHY The neuromodulation of the healthy oropharyngeal swallow response was described in relation to bolus volume and viscosity challenges, using intraluminal pressure and impedance topography methods. Among a wide range of physiological measures, those indicative of distension pressure, luminal opening, and flow timing were most significantly altered by bolus condition, and therefore can be considered to be potential markers of swallow neuromodulation. The study methods and associated findings inform a diagnostic framework for swallow assessment in patients with oropharyngeal dysphagia.

Different barbed pharyngoplasty techniques for retropalatal collapse in obstructive sleep apnea patients: a systematic review

BACKGROUND

The use of barbed sutures (BS) for the treatment of retropalatal collapse and vibration in patients suffering from snoring and obstructive sleep apnea (OSA) has significantly increased in the last few years. Many surgeons have discovered the advantages and unique properties of the BS and allowed the popular surgical pharyngoplasty techniques to be updated and improved.

METHODS

A systematic review was performed to identify all the clinical studies concerning the different barbed pharyngoplasty (BP) techniques used for the treatment of palatal collapse in snoring and OSA patients. A qualitative analysis of data extracted was conducted.

RESULTS

We included 12 studies of which 10 are prospective and 2 retrospective: 9 single-arm studies on the efficacy of a specific BP technique, 1 randomized clinical trial on the comparison between BP and control groups, and 2 studies on the correlation between two different BP techniques. To date, in the literature, 5 different types of BP techniques have been described: barbed snore surgery, barbed reposition pharyngoplasty, barbed expansion sphincter pharyngoplasty, barbed suture suspension, and barbed soft palate posterior webbing flap pharyngoplasty. All the studies showed an overall improvement in the primary efficacy parameters investigated (apnea-hypopnea index, oxygen desaturation index, and Epworth sleepiness scale) in each of the surgical techniques performed without any major complications.

CONCLUSIONS

Given the extreme heterogeneity of the studies analyzed, it is necessary to perform more randomized and control studies on large samples aimed to define the best BP technique based on its effectiveness, surgical success rate, patient's compliance, and complications.

Palatopharyngoplasty and Palatal Anatomy and Phenotypes for Treatment of Sleep Apnea in the Twenty-first Century

Successful palatopharyngoplasty is critical for successful sleep apnea surgery. Traditional uvulopalatopharyngoplasty was primarily excisional, whereas newer techniques, such as expansion sphincterpharyngoplasty, are more reconstructive. Studies of flow dynamics even demonstrate that the effectiveness of maxillofacial surgery is significantly mediated through stiffening and enlargement of the lateral retropalatal and pharyngeal airway. The current modified technique of uvulopalatopharyngoplasty/expansion sphincteroplasty aims to maximize relocation and tension on the palatopharyngeus muscle, opening the retropalatal airway and the palatal genu, and minimizing tension on the final mucosal closure.

Obstructive sleep apnea syndrome (OSAS) and swallowing function-a systematic review

OBJECTIVES

The purpose of this systematic review was to summarize and qualitatively analyze published evidence elucidating the prevalence of dysphagia and detail alterations in swallowing function in patients with OSAS.

METHODS

Computerized literature searches were performed from four search engines. The studies were selected based on the inclusion and exclusion criteria. The studies were screened using Covidence (Cochrane tool) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards (PRISMA-2009). A total 2645 studies were initially retrieved, of which a total of 17 studies met inclusion criteria. Two reviewers, blinded to each other, evaluated level and strength of evidence using the Oxford Centre for Evidence-based Medicine Levels of Evidence and QualSyst, respectively.

RESULTS

Dysphagia prevalence ranged from 16 to 78% among the eligible studies. Studies varied in operational definitions defining swallowing dysfunction (dysphagia) and method used to assess swallowing function. Approximately 70% of eligible studies demonstrated strong methodological quality. The majority of studies (n = 11; 65%) reported pharyngeal swallowing impairments in patients with OSAS, including delayed initiation of pharyngeal swallow and penetration/aspiration.

CONCLUSION

This systematic review describes swallowing function in patients with OSAS. However, due to the variability in defining OSAS and dysphagia, in the assessment method used to determine dysphagia, and heterogeneity of study designs, true prevalence is difficult to determine. Clinicians involved in the management of OSAS patients should employ validated assessment measures to determine if swallow dysfunction is present.

High-resolution esophageal manometry in pediatrics: Effect of esophageal length on diagnostic measures

BACKGROUND

High-resolution esophageal manometry (HREM), derived esophageal pressure topography metrics (EPT), integrated relaxation pressure (IRP), and distal latency (DL) are influenced by age and size. Combined pressure and intraluminal impedance also allow derivation of metrics that define distension pressure and bolus flow timing. We prospectively investigated the effects of esophageal length on these metrics to determine whether adjustment strategies are required for children.

METHODS

Fifty-five children (12.3 ± 4.5 years) referred for HREM, and 30 healthy adult volunteers (46.9 ± 3.8 years) were included. Studies were performed using the MMS system and a standardized protocol including 10 × 5 mL thin liquid bolus swallows (SBM kit, Trisco Foods) and analyzed via Swallow Gateway (www.swallowgateway.com). Esophageal distension pressures and swallow latencies were determined in addition to EGJ resting pressure and standard EPT metrics. Effects of esophageal length were examined using partial correlation, correcting for age. Adult-derived upper limits were adjusted for length using the slopes of the identified linear equations.

KEY RESULTS

Mean esophageal length in children was 16.8 ± 2.8 cm and correlated significantly with age (r = 0.787, P = .000). Shorter length correlated with higher EGJ resting pressure and 4-s integrated relaxation pressures (IRP), distension pressures, and shorter contraction latencies. Ten patients had an IRP above the adult upper limit. Adjustment for esophageal length reduced the number of patients with elevated IRP to three.

CONCLUSIONS & INFERENCES

We prospectively confirmed that certain EPT metrics, as well as potential useful adjunct pressure-impedance measures such as distension pressure, are substantially influenced by esophageal length and require adjusted diagnostic thresholds specifically for children.

High-Resolution Pharyngeal Manometry and Impedance: Protocols and Metrics-Recommendations of a High-Resolution Pharyngeal Manometry International Working Group

High-resolution manometry has traditionally been utilized in gastroenterology diagnostic clinical and research applications. Recently, it is also finding new and important applications in speech pathology and laryngology practices. A High-Resolution Pharyngeal Manometry International Working Group was formed as a grass roots effort to establish a consensus on methodology, protocol, and outcome metrics for high-resolution pharyngeal manometry (HRPM) with consideration of impedance as an adjunct modality. The Working Group undertook three tasks (1) survey what experts were currently doing in their clinical and/or research practice; (2) perform a review of the literature underpinning the value of particular HRPM metrics for understanding swallowing physiology and pathophysiology; and (3) establish a core outcomes set of HRPM metrics via a Delphi consensus process. Expert survey results were used to create a recommended HRPM protocol addressing system configuration, catheter insertion, and bolus administration. Ninety two articles were included in the final literature review resulting in categorization of 22 HRPM-impedance metrics into three classes: pharyngeal lumen occlusive pressures, hypopharyngeal intrabolus pressures, and upper esophageal sphincter (UES) function. A stable Delphi consensus was achieved for 8 HRPM-Impedance metrics: pharyngeal contractile integral (CI), velopharyngeal CI, hypopharyngeal CI, hypopharyngeal pressure at nadir impedance, UES integrated relaxation pressure, relaxation time, and maximum admittance. While some important unanswered questions remain, our work represents the first step in standardization of high-resolution pharyngeal manometry acquisition, measurement, and reporting. This could potentially inform future proposals for an HRPM-based classification system specifically for pharyngeal swallowing disorders.

High-resolution manometry: what about the pharynx?

PURPOSE OF REVIEW

High-resolution pharyngeal manometry (HRPM) is a well tolerated, catheter-based, method for recording the pressures and bolus flow generated by the pharyngeal muscles during swallowing. Despite a body of published evidence and a critical mass of investigators in the field, there is a lack of consensus surrounding what biomechanical phenomena to measure. The purpose of this review is to provide some insights into the information on swallowing physiology that can be gathered using HRPM.

RECENT FINDINGS

HRPM literature has focused on measuring biomechanical phenomena that may be relevant to measure in relation to dysphagia research. This review focuses on the measurement of pharyngeal luminal occlusive forces, intrabolus distension pressure, bolus presence and bolus flow timing as key features of pharyngeal swallowing that require measurement and allow for derivation of the Swallow Risk Index, a global measure of swallow function indicative of swallowing functional reserve.

SUMMARY

HRPM allows objective derivation of measures of swallow function that may have value for diagnosis and research in relation to swallowing disorders. HRPM has demonstrated clinical applicability in specific patient populations and offers unique advantages that compliment current assessment methods.

The critical importance of pharyngeal contractile forces on the validity of intrabolus pressure as a predictor of impaired pharyngo-esophageal junction compliance

INTRODUCTION

Restrictive defects of the pharyngo-esophageal junction (PEJ) are common in both structural and neurological disorders and are amenable to therapies aiming to reduce outflow resistance. Intrabolus pressure (IBP) acquired with high-resolution manometry and impedance (HRMI) is an indicator of resistance and a marker of reduced PEJ compliance. Constraints and limitations of IBP as well as the optimal IBP parameter remain undefined.

AIMS

To determine: (i) the impact of peak pharyngeal pressure (PeakP) on the diagnostic accuracy of IBP for the detection of a restrictive defect at the PEJ and (ii) the optimal IBP parameter for this purpose.

METHODS

In 52 dysphagic patients previously treated for head and neck cancer. Five candidate IBP measures and PeakP were obtained with HRMI, as well as a presence of a stricture determined by a mucosal tear after endoscopic dilatation. Predictive values of IBP measures were evaluated by receiver operating characteristic (ROC) analysis for all patients and reiterated as patients with lowest PeakP were progressively removed from the cohort.

RESULTS

All IBP parameters had fair to good accuracy at predicting strictures. Intrabolus pressure measured at a discrete point of maximum admittance 1 cm above the maximal excursion of the upper esophageal sphincter had highest sensitivity (0.76) and specificity (0.78). When PeakP was at least 57 mm Hg both sensitivity and specificity improved to 0.9.

CONCLUSIONS

Pharyngeal propulsive force has substantial impact on the accuracy of IBP as a predictor of a PEJ stricture. When PeakP is ≥57 mm Hg, an elevated IBP is highly predictive of a restrictive defect at the PEJ.