Endoscopic dilatation improves long-term dysphagia following head and neck cancer therapies: a randomized control trial

Long-term pharyngeal dysphagia is a common complication following head and neck cancer (HNC) therapies. High-level evidence for pharyngoesophageal junction (POJ) dilatation as a treatment in this population is lacking. We aimed to evaluate the safety and efficacy of POJ dilatation in dysphagic HNC survivors. This single-center, single-blind, placebo-controlled trial (St George Hospital, Sydney, Australia) randomly assigned (1:1) HNC survivors with long-term dysphagia (≥12 months postcompleted HNC therapies) to receive either graded endoscopic dilatations or sham dilatation (placebo). Patients were blinded to intervention types. Two strata were used for permuted randomization: (1) HNC therapies (total laryngectomy vs. chemoradiation alone); (2) Prior POJ dilatation (nil vs. previous dilatation). The primary endpoint was a short-term clinical response in swallowing function (3 months), defined as (1) a decrease in Sydney Swallow Questionnaire score by ≥200 or a score ≤ ULN; and (2) satisfactory global clinical assessment. The secondary endpoints were dysphagia relapse and serious adverse events. This trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12617000707369). Between 13 January 2013 and 16 January 2017, 41 patients were randomly assigned to endoscopic dilatation (n = 21) or placebo (n = 20). The short-term response rate in the endoscopic dilatation group was 76% (n = 16), compared with 5% (n = 1) in the placebo group (P < 0.001). There were no serious adverse events. The finding of a mucosal tear postdilatation was associated strongly with clinical response (OR 13.4, 95% CI [2.4, 74.9], P = 0.003). Kaplan-Meier estimate of dysphagia relapse is 50% by 9.6 months (95% CI [6.0, 19.2]) from completion of dilatation. Endoscopic dilatation of the POJ is a safe and efficacious therapy for the treatment of long-term dysphagia in HNC survivors. Close follow-up and repeat dilatation are necessary given the high dysphagia relapse rate.

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.

Novel Intra-Procedural Distensibility Measurement Accurately Predicts Immediate Outcome of Pneumatic Dilatation for Idiopathic Achalasia

OBJECTIVES

Often 2-3 graduated pneumatic dilatations (PD) are required to treat achalasia as there is no current intra-procedural predictor of clinical response. Distensibility measurements using functional lumen imaging probe (FLIP) may provide an intra-procedural predictor of outcome. Our aim was to determine the optimal criterion for esophagogastric junction (EGJ) distensibility measurements during PD that predicts immediate clinical response.

METHODS

EGJ distensibility was prospectively measured using FLIP immediately pre- and post-PD. The EGJ distensibility index (EGJ-DI) was defined as a ratio of the narrowest cross-sectional area and the corresponding intra-bag pressure at 40 ml distension. Immediate and short-term clinical responses were defined as Eckardt score ≤3 assessed 2 weeks Post-PD and at 3-month follow-up, respectively.

RESULTS

In 54 patients, we performed thirty-seven 30 mm; twenty 35 mm and six 40 mm PDs. The short-term response rate to the graded PD was 93% (27/29) in newly diagnosed achalasia; 87% (13/15) and 70% (7/10) in those who had relapsed after previous PD and Heller's Myotomy, respectively. Among those demonstrating an immediate response, EGJ-DI increased by an average of 4.5 mm²/mmHg (95% CI (3.5, 5.5) (P<0.001). Within-subject Δ EGJ-DI was highly predictive of immediate clinical response with AUROC of 0.89 (95% CI [0.80, 0.98], P<0.001). An increment in EGJ-DI of 1.8 mm²/mmHg after a single PD predicts an immediate response with an accuracy of 87%.

CONCLUSIONS

FLIP-measured Δ EGJ-DI is a novel intra-procedural tool that accurately predicts immediate clinical response to PD in achalasia. This technique may potentially dictate an immediate mechanism to "step-up" dilator size within a single endoscopy session.

Inter-rater reliability and validity of automated impedance manometry analysis and fluoroscopy in dysphagic patients after head and neck cancer radiotherapy

BACKGROUND

Pharyngeal automated impedance manometry (AIM) analysis is a novel non-radiological method to analyze swallowing function based on impedance-pressure recordings. In dysphagic head and neck cancer patients, we evaluated the reliability and validity of the AIM-derived swallow risk index (SRI) and a novel measure of postswallow residue (iZn/Z) by comparing it against videofluoroscopy as the gold standard.

METHODS

Three blinded experts classified 88 videofluoroscopic swallows from 16 patients for aspiration and degree of postswallow residue. Pressure-impedance recordings of the patient and age-matched control swallows were analyzed using AIM by three observers who derived the SRI and iZn/Z. Intra-class correlation coefficients (ICC) were calculated for videofluoroscopic and AIM measures. Patient pressure/impedance measurements were compared with videofluoroscopy scores and control subjects to determine validity for detecting clinically relevant swallowing dysfunction.

KEY RESULTS

Agreement among observers assessing presence of penetration and aspiration was modest (ICC 0.57) for videofluoroscopy and good (ICC 0.71, 0.82) for AIM-derived SRI and iZn/Z. When compared with age-matched controls, the SRI was higher in patients with aspiration (mean diff. 28.6, 95% CI [55.85, 1.355], p < 0.05). The iZn/Z had moderate positive correlation with bolus residue on fluoroscopy (BRS score) (rs (86) = 0.4120, p < 0.0001) and was increased in both patients with aspiration (∆244 [419.7, 69.52; p < 0.05]) and penetration (∆240 [394.3, 85.77]; p < 0.05) compared to controls.

CONCLUSIONS & INFERENCES

AIM-based measures of swallowing function have better inter-rater reliability than comparable fluoroscopically derived measures. These measures are easily determined and objective markers of clinically relevant features of disordered swallowing following radiotherapy.

Correlation of esophageal pressure-flow analysis findings with bolus transit patterns on videofluoroscopy

Pressure-flow analysis quantifies the interactions between bolus transport and pressure generation. We undertook a pilot study to assess the interrelationships between pressure-flow metrics and fluoroscopically determined bolus clearance and bolus transport across the esophagogastric junction (EGJ). We hypothesized that findings of abnormal pressure-flow metrics would correlate with impaired bolus clearance and reduced flow across the EGJ. Videofluoroscopic images, impedance, and pressure were recorded simultaneously in nine patients with dysphagia (62-82 years, seven male) tested with liquid barium boluses. A 3.6 mm diameter solid-state catheter with 25 × 1 cm pressure/12 × 2 cm impedance was utilized. Swallowed bolus clearance was assessed using a validated 7-point radiological bolus transport scale. The cumulative period of bolus flow across the EGJ was also fluoroscopically measured (EGJ flow time). Pressure only parameters included the length of breaks in the 20 mmHg iso-contour and the 4 second integrated EGJ relaxation pressure (IRP4s). Pressure-flow metrics were calculated for the distal esophagus, these were: time from nadir impedance to peak pressure (TNadImp to PeakP) to quantify bolus flow timing; pressure flow index (PFI) to integrate bolus pressurization and flow timing; and impedance ratio (IR) to assess bolus clearance. When compared with controls, patients had longer peristaltic breaks, higher IRs, and higher residual EGJ relaxation pressures (break length of 8 [2, 13] vs. 2 [0, 2] cm, P = 0.027; IR 0.5 ± 0.1 vs. 0.3 ± 0.0, P = 0.019; IRP4s 11 ± 2 vs. 6 ± 1 mmHg, P = 0.070). There was a significant positive correlation between higher bolus transport scores and longer peristaltic breaks (Spearman correlation r = 0.895, P < 0.001) and with higher IRs (r = 0.661, P < 0.05). Diminished EGJ flow times correlated with a shorter TNadImp to PeakP (r = -0.733, P < 0.05) and a higher IR (r = -0.750, P < 0.05). Longer peristaltic breaks and higher IR correlate with failed bolus clearance on videofluoroscopy. The metric TNadImp to PeakP appears to be a marker of the period of time over which the bolus flows across the EGJ.

Low-resolution colonic manometry leads to a gross misinterpretation of the frequency and polarity of propagating sequences: Initial results from fiber-optic high-resolution manometry studies

BACKGROUND

High-resolution manometry catheters are now being used to record colonic motility. The aim of this study was to determine the influence of pressure sensor spacing on our ability to identify colonic propagating sequences (PS).

METHODS

Fiber-optic catheters containing 72-90 sensors spaced at 1 cm intervals were placed colonoscopically to the cecum in 11 patients with proven slow transit constipation, 11 patients with neurogenic fecal incontinence and nine healthy subjects. A 2 h section of trace from each subject was analyzed. Using the 1 cm spaced data as the gold standard, each data set was then sub-sampled, by dropping channels from the data set to simulate sensor spacing of 10, 7, 5, 3, and 2 cm. In blinded fashion, antegrade and retrograde PS were quantified at each test sensor spacing. The data were compared to the PSs identified in the corresponding gold standard data set.

KEY RESULTS

In all subject groups as sensor spacing increased; (i) the frequency of identified antegrade and retrograde PSs decreased (P < 0.0001); (ii) the ratio of antegrade to retrograde PSs increased (P < 0.0001); and (iii) the number of incorrectly labeled PSs increased (P < 0.003).

CONCLUSIONS & INFERENCES

Doubling the sensor spacing from 1 to 2 cm nearly halves the number of PSs detected. Tripling the sensor spacing from 1 to 3 cm resulted in a 30% chance of incorrectly labeling PSs. Closely spaced pressure recording sites (<2 cm) are mandatory to avoid gross misrepresentation of the frequency, morphology, and directionality of colonic propagating sequences.

Long-term outcome following pneumatic dilatation as initial therapy for idiopathic achalasia: an 18-year single-centre experience

BACKGROUND

Relapse after treatment for idiopathic achalasia is common and long-term outcome data are limited.

AIM

To determine the cumulative relapse rate and long-term outcome after pneumatic dilatation (PD) for achalasia in a tertiary referral centre.

METHODS

A retrospective study of 301 patients with achalasia treated with PD as first-line therapy. Short-term outcome was measured at 12 months. Long-term outcome was assessed in those who were in remission at 12 months by cumulative relapse rate and cross-sectional analysis of long-term remission rate regardless of any interval therapy, using a validated achalasia-specific questionnaire.

RESULTS

Eighty-two percent of patients were in remission 12 months following initial PD. Relapse rates thereafter were 18% by 2 years; 41% by 5 years and 60% by 10 years. Whilst 43% patients underwent additional treatments [PD (29%), myotomy (11%) or botulinum toxin (3%)] beyond 12 months, 32% of those who had not received interval therapy had relapsed at cross-sectional analysis. After a mean follow-up of 9.3 years, regardless of nature, timing or frequency of any interval therapy, 71% (79/111) patients were in remission. The perforation rate from PD was 2%. Chest pain had a poor predictive value (24%) for perforation.

CONCLUSIONS

Long-term relapse is common following pneumatic dilatation. While on-demand pneumatic dilatation for relapse yields a good response, one-third of relapsers neither seek medical attention nor receive interval therapy. Close follow-up with timely repeat dilatation is necessary for a good long-term outcome. Given the poor predictive value of chest pain for perforation, routine gastrografin swallow is recommended postdilatation.

Modulation of esophageal afferent pathways by 5-HT3 receptor inhibition

BACKGROUND

The study aims were to investigate whether neural pathways involving 5-HT3 receptors mediate: (i) distension-induced upper esophageal sphincter (UES) relaxation reflex, (ii) esophageal sensitivity to acid and electrical stimuli, and (iii) viserosomatic sensitization following acid exposure.

METHODS

In Study I, in a double-blind crossover trial (n = 9) esophageal sensory and pain thresholds to electrical stimulation were measured in the esophagus, midsternum, and the foot, before subjects were randomized to receive either Ondansetron (8 mg i.v.) or NaCl (0.9% w/v). HCl (0.15 mol L(-1)) was then infused into distal esophagus and electrical thresholds were reassessed. Following electrical sensory threshold testing, subjects received a second esophageal infusion of HCl to evaluate esophageal sensitivity to acid. In Study II (N = 10), frequencies of distension-induced UES relaxation responses were scored before and after treatment with Ondansetron and NaCl in a double-blind crossover trial.

KEY RESULTS

In Study I, ondansetron had no effect on esophageal sensitivity to HCl or acid-induced sensitization. However, blockade of 5-HT3 receptors did reduce midsternum somatic pain thresholds. Sixty minutes after esophageal acid exposure, pain thresholds were significantly lower in the ondansetron arm (mean Δ-1.36 ± 0.4 mA) when compared with NaCl (mean Δ-0.14 ± 0.58 mA) (P < 0.05). In Study II, 5-HT3 receptor blockade had no significant effect on UES relaxation reflex.

CONCLUSIONS & INFERENCES

This study does not support the hypothesis that in health, 5-HT3 receptors play a significant role in esophago-UES distention-induced relaxation reflex and esophageal sensitivity to acid or electrical stimulation. It does provide new evidence for involvement of 5-HT3 receptors in viscerosomatic sensitization.

Pancolonic motor response to subsensory and suprasensory sacral nerve stimulation in patients with slow-transit constipation

BACKGROUND

Sacral nerve stimulation (SNS) is emerging as a potential treatment for patients with constipation. Although SNS can elicit an increase in colonic propagating sequences (PSs), the optimal stimulus parameters for this response remain unknown. This study evaluated the colonic motor response to subsensory and suprasensory SNS in patients with slow-transit constipation.

METHODS

Patients with confirmed slow-transit constipation were studied. Either a water-perfused manometry catheter or a high-resolution fibre-optic manometry catheter was positioned colonoscopically to the caecum. A temporary electrode was implanted transcutaneously in the S3 sacral nerve foramen. In the fasted state, three conditions were evaluated in a double-blind randomized fashion: sham, subsensory and suprasensory stimulation. Each 2-h treatment period was preceded by a 2-h basal period. The delta (Δ) value was calculated as the frequency of the event during stimulation minus that during the basal period.

RESULTS

Nine patients had readings taken with a water-perfused catheter and six with a fibre-optic catheter. Compared with sham stimulation, suprasensory stimulation caused a significant increase in the frequency of PSs (mean(s.d.) Δ value - 1·1(7·2) versus 6·1(4·0) PSs per 2 h; P = 0·004). No motor response was recorded in response to subsensory stimulation compared with sham stimulation. Compared with subsensory stimulation, stimulation at suprasensory levels caused a significant increase in the frequency of PSs (P = 0·006).

CONCLUSION

In patients with slow-transit constipation, suprasensory SNS increased the frequency of colonic PSs, whereas subsensory SNS stimulation did not. This has implications for the design of therapeutic trials and the clinical application of the device.

Pancolonic spatiotemporal mapping reveals regional deficiencies in, and disorganization of colonic propagating pressure waves in severe constipation

BACKGROUND

The morphology, motor responses and spatiotemporal organization among colonic propagating sequences (PS) have never been defined throughout the entire colon of patients with slow transit constipation (STC). Utilizing the technique of spatiotemporal mapping, we aimed to demonstrate 'manometric signatures' that may serve as biomarkers of the disorder.

METHODS

In 14 female patients with scintigraphically confirmed STC, and eight healthy female controls, a silicone catheter with 16 recording sites spanning the colon at 7.5 cm intervals was positioned colonoscopically with the tip clipped to the cecum. Intraluminal pressures were recorded for 24 h.

KEY RESULTS

Pan-colonic, 24 h, spatiotemporal mapping identified for the first time in STC patients: a marked paucity of propagating pressure waves in the midcolon (P = 0.01), as a consequence of a significant (P < 0.0001) decrease in extent of propagation of PS originating in the proximal colon; an increase in frequency of retrograde PS in the proximal colon; a significant reduction in the spatiotemporal organization among PS (P < 0.001); absence of the normal nocturnal suppression of PS.

CONCLUSIONS & INFERENCES

Pancolonic, 24 h, spatiotemporal pressure mapping readily identifies characteristic disorganization among consecutive PS, regions of diminished activity and absent or deficient fundamental motor patterns and responses to physiological stimuli. These features are all likely to be important in the pathophysiology of slow transit constipation.

Bowel preparation affects the amplitude and spatiotemporal organization of colonic propagating sequences

BACKGROUND

Colonic manometry is performed using either colonoscopically assisted catheter placement, after bowel preparation, or nasocolonic intubation of the unprepared bowel. There has been little systematic evaluation of the effects of bowel cleansing upon colonic propagating pressure wave sequences.

METHODS

Eight healthy volunteers underwent nasocolonic placement of a water-perfused silicone catheter which recorded pressures at 16 recording sites each spaced 7.5 cm apart in the unprepared colon for 24 h. These measures were compared with those obtained in another eight healthy volunteers in whom the catheter was placed to the caecum at colonoscopy in the prepared colon.

KEY RESULTS

The colonic motor responses to meals and morning waking, and the normal nocturnal suppression did not differ between the two groups, nor were the overall frequency, regional dependence nor extent of propagating sequences (PS) influenced by bowel preparation. Bowel preparation did result in a significant increase in the frequency of high amplitude PS (22 +/- 7 vs 8 +/- 4 HAPS/24 h; P = 0.003). Additionally, a number of the measures of spatiotemporal organization among consecutive PS (linkage among sequences and predefecatory stereotypical patterning) were significantly altered by bowel preparation.

CONCLUSIONS & INFERENCES

The overall frequency of PSs, the colonic responses to physiological stimuli such a meal and morning waking and nocturnal suppression, are not influenced by prior bowel preparation. However, investigators wishing to study HAPS frequency, or the more complex spatiotemporal relationships among consecutive PSs, should control for bowel preparation when making comparisons among study groups.

Upregulation of the esophago-UES relaxation response: a possible pathophysiological mechanism in suspected reflux laryngitis

BACKGROUND

Inappropriate or excessive, non-swallow related, reflexive relaxation of the upper esophageal sphincter (UES) in response to esophageal distension may be the principal mechanism permitting retrograde trans-sphincteric flow during acid regurgitation. The neural pathways mediating reflexive UES relaxation in the human have received little attention. Patients with laryngitis demonstrate an increased acid reflux in the proximal esophagus. Such events, combined with an increased tendency for UES relaxation, might precipitate regurgitation into the pharynx. The aim was to determine whether the esophago-UES relaxation reflex induced by rapid esophageal distension is upregulated in patients with posterior laryngitis.

METHODS

In 21 healthy volunteers and 14 patients with posterior laryngitis, UES responses to rapid air insufflation were examined. UES responses were monitored with perfused manometry catheter with a oval sleeve sensor.

KEY RESULTS

The probability of triggering UES relaxation in response to the rapid esophageal air distension, for all volumes of insufflation, was higher in laryngitis (45%) than in health (17%). The minimum distension volume required to elicit an UES relaxation response was significantly lower in laryngitis patients when compared with controls. Patients who demonstrated a laryngoscopic response to a trial of omeprazole, were less likely to generate a distension-induced UES contractile response (5%) than patients who did not respond (23%).

CONCLUSIONS & INFERENCES

The threshold for esophageal distension-induced UES relaxation is reduced in patients with laryngitis when compared with controls. This finding supports the hypothesis that in this population, a hypersensitive belch-like response may be one contributory mechanism of regurgitation when triggered by an abrupt spontaneous gastro-esophageal reflux event.

Chronic constipation: overview and challenges

Despite its high prevalence and cost implications, our understanding of the pathophysiology of constipation remains primitive, and available therapies have limited efficacy. The purpose of this supplement is to address critically the reasons for the current lack of understanding and to propose avenues of future research to address these deficiencies.

Evidence for oesophageal visceral hypersensitivity and aberrant symptom referral in patients with globus

We tested the hypotheses that globus patients demonstrate oesophageal visceral hypersensitivity and aberrant viscerosomatic referral of oesophageal stimuli. Oesophageal visceral perception was assessed by oesophageal balloon distension and electrical stimulation in nine patients with globus and compared with 11 healthy controls. Oesophageal perception and pain thresholds were determined. Subjects recorded the area of thoracic viscerosomatic referral on a body map in response to each stimulus. All the patients reported their first sensation at balloon volumes between 2 and 6 mL whereas controls reported their first sensation at volumes between 3 and 14 mL (P = 0.03). All the patients reported pain at balloon volumes between 5 and 12 mL whereas controls experienced pain at volumes between 8 and 20 mL (P = 0.001). In response to electrical stimulation to the oesophagus patients and controls demonstrated comparable sensory thresholds. In response to oesophageal balloon distension seven of nine patients, but no controls, referred the sensation to the region at or above the suprasternal notch (P = 0.001). Similarly, significant differences in viscerosomatic referral pattern were observed in response to oesophageal electrical stimulation (P = 0.03). Patients with globus demonstrate oesophageal visceral hypersensitivity to mechanical distension. The differential responses to stretch and electrical stimuli may indicate that the hypersensitivity is a peripheral, rather than central, phenomenon. The aberrant referral of oesophageal sensations in response to both mechanical and electrical stimulation supports the hypothesis that referral of symptoms to the neck might be a central phenomenon.

Spatio-temporal analysis reveals aberrant linkage among sequential propagating pressure wave sequences in patients with symptomatically defined obstructed defecation

Available evidence implicates abnormal colonic contractility in patients suffering from constipation. Traditional analysis of colonic manometry focuses on the frequency, extent and amplitude of propagating sequences (PS). We tested the hypotheses that the spatio-temporal linkage among sequential PSs exists throughout the healthy human colon and is disrupted during constipation. In eight patients with severe constipation and eight healthy volunteers, we recorded colonic pressures from 16 regions (caecum-rectum) for 24 h. Sequential PSs were regionally linked if the two PSs originated from different colonic regions but the segments of colon traversed by each PS overlapped. In order to determine whether this linkage occurred by chance, a computer program was used to randomly rearrange all PSs in time. Data were re-analysed to compare regional linkage between randomly re-ordered PSs (expected) and the natural distribution of PSs (observed). In controls the observed regional linkage (82.5 +/- 9.0%) was significantly greater than the expected value (60.5 +/- 4.3%; P = 0.0001). In patients the observed and expected regional linkage did not differ. The (observed - expected) delta value of regional linkage in controls was significantly greater than in patients (21.7 +/- 8.5%vs-2.3 +/- 7.0%; P = 0.01). Regional linkage among sequential PSs in the healthy colon appears to be a real phenomenon and this linkage is lost in patients with constipation. Regional linkage may be important for normal colonic transit and loss of linkage might have pathophysiological relevance to and provide a useful biomarker of severe constipation.

In-vivo demonstration of a high resolution optical fiber manometry catheter for diagnosis of gastrointestinal motility disorders

Fiber optic catheters for the diagnosis of gastrointestinal motility disorders are demonstrated in-vitro and in-vivo. Single element catheters have been verified against existing solid state catheters and a multi-element catheter has been demonstrated for localized and full esophageal monitoring. The multi-element catheter consists of a series of closely spaced pressure sensors that pick up the peristaltic wave traveling along the gastrointestinal (GI) tract. The sensors are spaced on a 10 mm pitch allowing a full interpolated image of intraluminal pressure to be generated. Details are given of in-vivo trials of a 32-element catheter in the human oesophagus and the suitability of similar catheters for clinical evaluation in other regions of the human digestive tract is discussed. The fiber optic catheter is significantly smaller and more flexible than similar commercially available devices making intubation easier and improving patient tolerance during diagnostic procedures.

Intraluminal impedance detects failure of pharyngeal bolus clearance during swallowing: a validation study in adults with dysphagia

Multichannel intraluminal impedance (MII) detects bolus flow through a healthy pharynx. The aim of this study was to determine whether the technique detects bolus flow and retention in patients with pharyngeal dysphagia; develop appropriate impedance-based criteria for assessing patients and to provide some preliminary insights into the clinical utility of the technique. Pharyngo-oesophageal pressure and impedance were recorded simultaneously with videofluoroscopy (VF) during swallows in six patients with dysphagia. Agreement, as to the presence or absence of bolus material, between the VF and MII was expressed using the Cohen's Kappa statistic. To test whether the impedance criteria for the detection of bolus passage in dysphagia could be improved, a Kappa statistic was calculated in an iterative process for a range of impedance values (100%-0%) defining bolus head entry and bolus tail clearance from the pharynx. Bolus presence according to the MII criteria previously derived by us in healthy controls demonstrated a modest correlation with VF when applied to this dysphagia population [0.37, 0.5 and 0.58 in the hypopharynx, upper oesophageal sphincter (UOS) and proximal oesophagus respectively]. In the patient population, the optimal impedance criteria were 50% for bolus head entry and 20% for bolus tail clearance. Adopting these criteria demonstrated enhanced agreement between VF and impedance; yielding Kappa coefficients of 0.42 in the hypopharynx, 0.54 in the UOS and 0.62 in the proximal oesophagus. With the adoption of appropriate criteria, pharyngeal impedance measurement can accurately detect bolus passage and failed or impaired clearance during swallowing in patients with dysphagia.

Proximal versus distal oesophageal motility as assessed by combined impedance and manometry

BACKGROUND

Regional differences in oesophageal motility have been shown in primary peristalsis, but it is unclear whether such differences occur in secondary peristalsis. We investigated whether oesophageal motor function differs between the proximal and distal oesophagus.

METHODS

Eleven healthy subjects were studied with combined impedance and manometry. Saline and solid agar boluses of 5 ml were applied for primary peristalsis, and secondary peristalsis was stimulated by rapid mid-oesophageal injections of saline. Impedance tracings were analysed and compared for bolus presence time, bolus transit time in the proximal and distal oesophagus.

RESULTS

Most of the manometric parameters were not significantly different between the proximal and distal oesophagus. Bolus presence time was longer in the distal oesophagus for both primary peristalsis and secondary peristalsis (p<0.001). The proximal bolus transit time was shorter than the distal bolus transit time during saline and solid swallows (p<0.001). Bolus transit time and bolus presence time were shorter for primary peristalsis than secondary peristalsis induced by saline injection.

CONCLUSION

Our data demonstrated that the impedance technique can successfully detect functional differences between the proximal and distal oesophagus, and such differences were still noticeable when the oesophagus was directly stimulated by saline injection.

Determinants of postprandial flow across the human ileocaecal junction: a combined manometric and scintigraphic study

The relationships between ileocolonic motor patterns and flow have not been defined in humans. Utilizing simultaneous ileocolonic manometry and scintiscanning, we aimed to examine this relationship and test the hypotheses that ileal propagating sequences (PSs) underlie caecal filling, that caecal filling is a stimulus for proximal colonic PSs and that the ileocolonic junction (ICJ) regulates flow between the small and large bowel. In six healthy volunteers, a 5-m-long nasocolonic manometry catheter was positioned such that 16 recording sites, spaced at 7.5-cm intervals, spanned the ileum and proximal colon. Subjects were positioned under a gamma camera 30 MBq of (99m)Tc sulphur colloid was instilled, 22.5 cm proximal to the ICJ. Isotopic images were recorded (10 s per frame) and synchronized with the manometric trace. We identified 171 ileal PSs, 47 caecal PSs and 117 discrete episodes of caecal filling. Of the 117 episodes of caecal filling, 72% were associated temporally with ileal PSs. Conversely, 87% of ileal PSs were associated with caecal filling. Of the PSs originating in the caecum, 90% were temporally associated with caecal filling. We conclude that ileal PSs are highly propulsive and are the major determinant of episodic caecal filling and that caecal filling may be a major stimulus for caecal propagating sequences.

Identification of impaired oesophageal bolus transit and clearance by secondary peristalsis in patients with non-obstructive dysphagia

Impaired secondary peristalsis has been shown in non-obstructive dysphagia (NOD). The relationship between such changes and alterations in bolus transport has not been studied. The aim of this study was to evaluate the integrity and characteristics of oesophageal bolus transit by secondary peristalsis in NOD patients with multichannel intraluminal impedance (MII). Eleven healthy volunteers and 10 consecutive patients underwent combined MII recording and manometry. Secondary peristalsis was stimulated by mid-oesophageal injections of saline. Values for bolus presence time at each of the recording sites and bolus transit time were calculated. Bolus transit was considered to be complete when impedance defined complete bolus clearance at all recording sites. Secondary peristaltic responses were triggered significantly less frequently in patients with NOD than in controls (P < 0.001). The proportion of secondary peristalsis demonstrating complete bolus transit was lower in NOD patients than in controls (P < 0.001). Oesophageal bolus transit time by secondary peristalsis was longer in NOD patients than in controls (P = 0.005), as was bolus presence time at each of the recording sites (P < 0.05). When compared with controls, NOD patients demonstrated a higher proportion of incomplete bolus transit in response to normal secondary peristalsis (P < 0.001). Abnormal bolus transit occurred more often associated with ineffective and synchronous responses than normal responses in both groups studied (P < 0.001). Multichannel intraluminal impedance identifies functional defects of oesophageal bolus clearance by secondary peristalsis in NOD patients and such defects are characterized by a longer oesophageal dwell and a prolonged clearance time.

Twenty-four hour spatiotemporal mapping of colonic propagating sequences provides pathophysiological insight into constipation

Colonic propagating sequences (PS)s are a major determinant of luminal propulsion. A global appreciation of spatiotemporal patterning of PSs requires evaluation of 24 h pan-colonic recordings, a difficult task given that PSs are relatively infrequent events that are not uniformly distributed throughout the colon. Here we developed a means of space-time-pressure 'mapping' in a condensed format, 24 h of colonic recording in such a manner that readily permits an overall view of colonic antegrade and retrograde colonic PSs within a single figure. Such graphical representation readily permits appreciation and identification of aberrant patterns in severe constipation and may be an important clinical and research tool in the assessment of colonic motor disorders.

Differences in oesophageal bolus transit between patients with and without erosive reflux disease

BACKGROUND

We determined any difference in oesophageal function between reflux patients with and without erosive esophagitis by the application of concurrent manometry and impedance.

METHODS

Twenty patients with erosive esophagitis, 20 patients with non-erosive reflux disease, and 15 controls were included in this study. All subjects underwent studies with a catheter containing four impedance-measuring segments and five solid-state pressure transducers. Each subject received 10 liquid and 10 viscous boluses to be swallowed.

RESULTS

Healthy controls had greater distal oesophageal peristaltic amplitude than both patient groups (p < 0.05). Normal oesophageal peristalsis was found more frequently in healthy controls than either of the patient groups (p < 0.05). Patients with erosive esophagitis exhibited a lower percentage of complete bolus transit compared to healthy controls and non-erosive reflux disease patients (both p < 0.05). Patients with erosive esophagitis had a longer total bolus transit time compared to healthy controls and non-erosive reflux disease patients (both p < 0.05).

CONCLUSIONS

Erosive esophagitis is characterized by longer oesophageal bolus transit and fewer complete bolus transit than non-erosive reflux disease. The noted differences in oesophageal bolus transit may reflect a continuum of dysfunction secondary to increasing oesophageal mucosal damage.

Optimal criteria for detecting bolus passage across the pharyngo-oesophageal segment during the normal swallow using intraluminal impedance recording

The impedance criteria for the detection of the arrival of bolus head and clearance of bolus tail in the pharynx have not been defined, and may differ from accepted criteria used in the oesophagus. Our aim was to define the optimal impedance criteria that most accurately defined passage of the swallowed bolus moving through the pharyngo-oesophageal segment. In eight healthy volunteers, an assembly incorporating seven impedance-measuring segments was positioned across the pharyngo-oesophageal segment, and subjects swallowed liquid and semisolid radio-opaque boluses (2-20 mL) while impedance was simultaneously recorded with videofluoroscopic images. To derive the optimal criteria, in an iterative process we correlated impedance defined bolus presence with fluoroscopy (Cohen's Kappa) for a range of impedance cut-off values from 100% to 0% for both the initial fall, and recovery of impedance. Bolus presence in the pharynx, as determined by the 'standard' criteria (50% drop and recovery to 50% of baseline), correlated very modestly with videofluoroscopy (kappa approximately 0.35). The criteria that most accurately defined bolus passage varied between pharyngeal regions. Threshold (% of baseline) for bolus head entry into the region ranged from 71% to 80%. Threshold for bolus tail clearance varied from nadir to 19%. Correlation of impedance with videofluoroscopy improved to kappa approximately 0.6 with the above criteria. The impedance criteria defining bolus presence across the pharyngo-oesophageal segment differ from those adopted in the oesophagus. Pharyngeal impedance provides an accurate, non-radiological indicator of bolus transit through the pharynx.

Proximal colonic propagating pressure waves sequences and their relationship with movements of content in the proximal human colon

Abnormal colonic motor patterns have been implicated in the pathogenesis of severe constipation. Yet in health, the mechanical link between movement of colonic content and regional pressures have only been partially defined. This is largely due to current methodological limitations. Utilizing a combination of simultaneous colonic manometry, high-resolution scintigraphy and a quantitative technique for detecting discrete episodic flow, our aim was to examine the propulsive properties of colonic propagating sequences (PS) in the healthy colon. In six healthy volunteers a nasocolonic manometry catheter was positioned to record colonic pressures at 7.5 cm intervals from terminal ileum to the splenic flexure. With subjects positioned under a gamma camera, 30 MBq of (99m)Tc sulfur colloid was instilled into the terminal ileum, 22.5 cm proximal to the ileocolonic junction. Isotopic images were recorded (10 s/frame) and synchronized with the manometric trace. In the proximal colon we identified 137 antegrade PSs, of which 93% were deemed to be associated temporally with movements of luminal content. Low amplitude PSs, with component pressure waves between 2 mmHg and 5 mmHg, were as likely to be associated with colonic movements as higher amplitude PSs. As such there was no correlation between the amplitude of the PS and the temporal relationship with colonic movements. Within the proximal colon, 24 retrograde PSs were identified, 23 of which were associated with retrograde movements of colonic content. We conclude that proximal colonic PSs are highly propulsive and are a major determinant of proximal colonic flow.

Sacral nerve stimulation induces pan-colonic propagating pressure waves and increases defecation frequency in patients with slow-transit constipation

OBJECTIVE

Colonic propagating sequences are important for normal colonic transit and defecation. The frequency of these motor patterns is reduced in slow-transit constipation. Sacral nerve stimulation (SNS) is a useful treatment for fecal and urinary incontinence. A high proportion of these patients have also reported altered bowel function. The effects of SNS on colonic propagating sequences in constipation are unknown. Our aims were to evaluate the effect of SNS on colonic pressure patterns and evaluate its therapeutic potential in severe constipation.

METHOD

In eight patients with scintigraphically confirmed slow-transit constipation, a manometry catheter (16 recording sites at 7.5 cm intervals) was positioned colonoscopically and the tip fixed in the caecum. Temporary electrodes (Medtronic) were implanted in the S2 and S3 sacral nerve foramina under general anaesthesia. In the fasted state, 14 Hz stimulation was administered and four sets of parameters (pulse width 300 or 400 micros; S2 and S3) were tested in four 2-h epochs, in random order, over 2 days. Patients were then discharged home with the sacral wires in situ and a 3-week trial stimulation commenced during which patients completed a daily stool diary.

RESULTS

When compared with basal activity, electrical stimulation to S3 significantly increased pan-colonic antegrade propagating sequence (PS) frequency (5.4 +/- 4.2 vs 11.3 +/- 6.6 PS/h; P=0.01). Stimulation at S2 significantly increased retrograde PSs (basal 2.6 +/- 1.8 vs SNS 5.6 +/- 4.8 PS/h; P=0.03). During the subsequent three-week trial (continuous stimulation), six of eight reported increased bowel frequency with a reduction in laxative usage.

CONCLUSION

These data demonstrate that SNS induces pan-colonic propagating pressure waves and therefore shows promise as a potential therapy for severe refractory constipation.

Validation of a semi-automated scintigraphic technique for detecting episodic, real-time colonic flow

The relationships between the movement of colonic content and regional pressures have only been partially defined. During the analysis of a combined colonic scintigraphic and manometric study, a quantitative technique for determining discrete, episodic, real-time colonic flow was developed. Our aim was to validate this technique through the construction of a computer-generated phantom model of known antegrade and retrograde motility. The anthropoid phantom was rasterized into a 6-mm voxel model to create a 3D voxel phantom of the colon with four distinct colonic segments. Associating a time/activity curve with each segment simulated dynamic behaviour. Activity in the model was based on data obtained from human colonic scintigraphic recordings using 30 MBq of (99m)Tc sulphur colloid. The flow was simulated by modifying the input time/activity functions to represent episodes of net flow of 2%, 5% or 10% of segmental content. Our quantitative technique was applied to the phantom model to measure the accuracy with which simulated flows were detected. Our quantitative technique proved to be a sensitive and specific means of detecting the presence and the magnitude of discrete episodes of colonic flow and therefore, should improve our ability to correlate colonic flow and motor patterns.

Removal of tonic nitrergic inhibition is a potent stimulus for human proximal colonic propagating sequences

Propagating sequences (PS) are important in colonic propulsion and defecation, yet the triggers of these motor patterns are not understood. Nonadrenergic noncholinergic neurones are believed to modulate smooth muscle in the gastrointestinal tract via the ubiquitous inhibitory neurotransmitter nitric oxide (NO). In the mouse colon periods of quiescence correlate with an increase in the release of NO. We investigated the colonic response to NO synthase inhibition in the conscious human subject. Intravenous infusion of saline or N(G)-monomethyl-L-arginine (L-NMMA; 3 or 6 mg kg(-1) h(-1)) occurred in random order in six healthy volunteers in whom a 5 m long nasocolonic manometry catheter was positioned such that 16 recording sites, at 7.5-cm intervals, spanned the terminal ileum and colon. L-NMMA infusion at 3 mg kg(-1) h(-1), but not 6 mg kg(-1) h(-1) significantly (P = 0.02) increased proximal colonic PS frequency (2.0 +/- 1.9 vs 11.7 +/- 7.0 PS h(-1)) and non-propagating motor activity (5,296 +/- 2,750 vs 6,362 +/- 1,275 mmHg s). We conclude that blockade of NO synthesis has a stimulatory effect on the frequency of proximal colonic PS. This suggests removal of tonic nitrergic inhibition of the colon might be a physiological stimulus for propagating activity.

Predictors of outcome in an open label, therapeutic trial of high-dose omeprazole in laryngitis

BACKGROUND

Gastroesophageal reflux is implicated in some cases of laryngitis. There are no established predictors of response to acid suppression therapy in suspected reflux laryngitis.

AIM

In a population with laryngitis, the aim is to determine whether (a) omeprazole 20 mg tds (3 months) improves symptoms and laryngitis, and (b) the outcome in response to potent acid suppression can be predicted by esophageal and/or pharyngeal parameters during ambulatory pH monitoring or by other pretreatment variables.

METHODS

From the 70 consecutive patients with laryngitis screened, 20 patients met the inclusion criteria (dysphonia >3 months; laryngoscopically demonstrated laryngitis); and 50 patients were excluded because of one or more criteria indicating alternative causes for laryngeal injury. The primary outcome measure was improvement of at least one level in a 4-point laryngitis grading at 3 months. Twenty-four-hour dual, pharyngo-esophageal pH monitoring was performed at baseline. Secondary outcomes (symptom questionnaire; computerized voice analysis) were measured at baseline, and at 6 and 12 wk.

RESULTS

Response rates at 6 and 12 wk were 47% and 63%, respectively. GERD symptoms (heartburn (p= 0.03) and regurgitation (p= 0.0001)) improved. However, neither baseline GERD symptoms nor endoscopic findings predicted laryngoscopic or symptomatic response. Neither baseline laryngitis grade (p= 0.46) nor esophageal acid exposure on pH testing (p= 0.3) predicted outcome. Four of 20 patients demonstrated pharyngeal regurgitation on pH testing, all four of whom responded to potent acid suppression (p= 0.2). Computerized voice measures were not predictive of outcome, although fundamental frequency (Fo) was inversely related to baseline laryngoscopic grade.

CONCLUSION

In a carefully defined population of patients with laryngitis (a) 63% have a laryngoscopic response to 3 months of potent acid suppression without significant improvement in laryngeal symptoms; (b) neither voice measures, esophageal acid exposure time, symptoms nor severity of laryngitis predict outcome; and (c) although numbers were small, all patients with a positive pharyngeal pH study responded to therapy and pharyngeal pH-metry may prove useful; (4) available evidence supports an empiric trial of high-dose proton pump inhibitors (PPI), for at least 12 wk, as the initial diagnostic step for suspected reflux laryngitis.

Oropharyngeal Scintigraphy: A Reliable Technique for the Quantitative Evaluation of Oral–Pharyngeal Swallowing

A valid and reliable technique to quantify the efficiency of the oral-pharyngeal phase of swallowing is needed to measure objectively the severity of dysphagia and longitudinal changes in swallowing in response to intervention. The objective of this study was to develop and validate a scintigraphic technique to quantify the efficiency of bolus clearance during the oral-pharyngeal swallow and assess its diagnostic accuracy. To accomplish this, postswallow oral and pharyngeal counts of residual for technetium-labeled 5- and 10-ml water boluses and regional transit times were measured in 3 separate healthy control groups and in a group of patients with proven oral-pharyngeal dysphagia. Repeat measures were obtained in one group of aged (> 55yr) controls to establish test-retest reliability. Scintigraphic transit measures were validated by comparison with radiographic temporal measures. Scintigraphic measures in those with proven dysphagia were compared with radiographic classification of oral vs. pharyngeal dysfunction to establish their diagnostic accuracy. We found that oral ( p = 0.04), but not pharyngeal, isotope clearance is swallowed bolus-dependently. Scintigraphic transit times do not differ from times derived radiographically. All scintigraphic measures have extremely good test-retest reliability. The mean difference between test and retest for oral residual was -1% (95% CI -3%-1%) and for pharyngeal residual it was -2% (95% CI -5%-1%). Scintigraphic transit times have very poor diagnostic accuracy for regional dysfunction. Abnormal oral and pharyngeal residuals have positive predictive values of 100% and 92%, respectively, for regional dysfunction. We conclude that oral-pharyngeal scintigraphic clearance is highly reliable, bolus volume-dependent, and has a high predictive value for regional dysfunction. It may prove useful in assessment of dysphagia severity and longitudinal change.

Biomechanics, diagnosis, and treatment outcome in inflammatory myopathy presenting as oropharyngeal dysphagia

AIMS

In patients with inflammatory myopathy and dysphagia, our aims were to determine: (1) the diagnostic utility of clinical and laboratory indicators; (2) the biomechanical properties of the pharyngo-oesophageal segment; (3) the usefulness of pharyngeal videomanometry in distinguishing neuropathic from myopathic dysphagia; and (4) clinical outcome.

METHODS

Clinical, laboratory, and videomanometric assessment was performed in 13 patients with myositis and dysphagia, in 17 disease controls with dysphagia (due to proven CNS disease), and in 22 healthy age matched controls. The diagnostic accuracy of creatine kinase (CPK), erythrocyte sedimentation rate, antinuclear antibody, and electromyography (EMG) were compared with the gold standard muscle biopsy. The biomechanical properties of the pharyngo-oesophageal segment were assessed by videomanometry.

RESULTS

Mean time from dysphagia onset to the diagnosis of myositis was 55 months (range 1-180). One third had no extrapharyngeal muscle weakness; 25% had normal CPK, and EMG was unhelpful in 28%. Compared with neurogenic controls, myositis patients had more prevalent cricopharyngeal restrictive disorders (69% v 14%; p=0.0003), reduced upper oesophageal sphincter (UOS) opening (p=0.01), and elevated hypopharyngeal intrabolus pressures (p=0.001). Videomanometric features favouring a myopathic over a neuropathic aetiology were: preserved pharyngeal swallow response, complete UOS relaxation, and normal swallow coordination. The 12 month mortality was 31%.

CONCLUSIONS

The notable lack of supportive clinical signs and significant false negative rates for laboratory tests contribute to the marked delay in diagnosis. The myopathic process is strongly associated with restricted sphincter opening suggesting that cricopharyngeal disruption is a useful adjunct to immunosuppressive therapy. The condition has a poor prognosis.

Esophageal pneumatic dilation for postfundoplication dysphagia: safety, efficacy, and predictors of outcome

OBJECTIVE

Persistent dysphagia occurs in 5-10% of patients after fundoplication. The cause is obscure in most cases, and the management has not been well established. The aim of this study is to evaluate the clinical outcomes and the predictors of success for esophageal pneumatic dilations in patients with dysphagia after fundoplication.

METHODS

We retrospectively reviewed 14 patients who underwent pneumatic dilation for persistent postfundoplication dysphagia. All patients had esophageal manometry before dilations.

RESULTS

There were nine responders to pneumatic dilations (30-40-mm balloons). The nadir lower esophageal sphincter (LES) relaxation pressure was the only significant predictor for successful dilation and was higher among the responders than nonresponders (median 10 mm Hg vs 5 mm Hg). All six of 14 patients with nadir LES pressure > or = 10 mm Hg had a good response. There was no significant difference in the LES basal pressure between the responders and nonresponders (median 20 mm Hg vs 12 mm Hg). The median distal peristaltic amplitude (74 mm Hg vs 69 mm Hg), percent of failed peristalsis (8% vs 45%), and ramp pressure (19 mm Hg vs 17 mm Hg) did not differ significantly between the responders and nonresponders. No perforations occurred.

CONCLUSIONS

Pneumatic dilation is a reasonably safe and effective treatment for patients with postfundoplication dysphagia. Raised nadir LES relaxation pressure seems to be a useful predictor of successful outcome.

The proximal colonic motor response to rectal mechanical and chemical stimulation

We aimed to determine whether rectal distension and/or infusion of bile acids stimulates propagating or nonpropagating activity in the unprepared proximal colon in 10 healthy volunteers using a nasocolonic manometric catheter (16 recording sites at 7.5-cm spacing). Sensory thresholds and proximal colonic motor responses were assessed following rectal distension by balloon inflation and rectal instillation of chenodeoxycholic acid. Maximum tolerated balloon volume and the volume that stimulated a desire to defecate were both significantly (P < 0.01) reduced after rectal chenodeoxycholic acid. The frequency of colonic propagating pressure wave sequences decreased significantly in response to initial balloon inflations (P < 0.05), but the frequency doubled after subsequent chenodeoxycholic acid infusion (P < 0.002). Nonpropagating activity decreased after balloon inflation, was not influenced by acid infusion, and demonstrated a further decrease in response to repeat balloon inflation. We concluded that rectal chenodeoxycholic acid in physiological concentrations is a potent stimulus for propagating pressure waves arising in the proximal colon and reduces rectal sensory thresholds. Rectal distension inhibits all colonic motor activity.

Space-time pressure structure of pharyngo-esophageal segment during swallowing

We applied high-resolution manometry with spatiotemporal data interpolation and simultaneous videofluoroscopy to normal pharyngeal swallows to correlate specific features in the space-time intraluminal pressure structure with physiological events and normal deglutitive transsphincteric bolus flow to define normal biomechanical properties of the pharyngo-esophageal (PE) segment. Pressures were recorded by microperfused catheter, and the two-dimensional space-time data sets were plotted as isocontours. On these were superimposed bolus trajectories, anatomic segment movements, and hyo-laryngeal trajectories from concurrent videofluoroscopy. Correlation of the highly reproducible space-time-pressure structure with radiographic images confirmed that primary deglutitive PE segment functions (pressure profile, laryngeal elevation, axial sphincter motion, timing of relaxation, contraction) are accurately discernible from single isocontour pressure visualization. Pressure during bolus flow was highly dependent on axial location within PE segment and time instant. The intrabolus pressure domain, corresponding to the space-time region between bolus head and tail trajectories, demonstrated significant bolus volume dependence. High-resolution manometry accurately, comprehensively, and highly reproducibly depicts the PE segment space-time-pressure structure and specific physiological events related to upper esophageal sphincter opening and transsphincteric flow during normal swallowing. Intrabolus pressure variations are highly dependent on position within the PE segment and time.

Prolonged multi-point recording of colonic manometry in the unprepared human colon: providing insight into potentially relevant pressure wave parameters

OBJECTIVES

To determine the feasibility of and derive normative data for prolonged, 24-h, multipoint, closely spaced, water perfused manometry of the unprepared human colon.

METHODS

In 14 healthy volunteers, 24-h recordings were made using a water perfused, balloon-tipped, 17 lumen catheter which was passed pernasally and positioned so that 16 recording sites spanned the colon at 7.5 cm intervals from cecum to rectum. The area under the pressure curve and propagating pressure wave parameters were quantified for the 16 regions. High amplitude propagating sequences were defined as were rectal motor complexes.

RESULTS

Nasocolonic recording was well tolerated and achievable. Propagation sequences, including high amplitude propagating sequences, originated in the cecum (0.32 +/- 0.05/h) more frequently than in other regions and the extent of propagation correlated significantly with proximity of the site of sequence origin to the cecum (p < 0.001). Propagation velocity of propagating sequences was greater than high amplitude propagating sequences (p = 0.0002) and region-dependent, unlike high amplitude propagating sequences (p < 0.01). The frequency of propagating sequences did not increase after the meal, but frequency of high amplitude propagating sequences was increased significantly by the meal (p < 0.01). Rectal motor complexes were seen throughout the colon with no apparent periodicity.

CONCLUSIONS

Prolonged, multipoint, perfusion manometry of the unprepared colon provides improved spatial resolution of colonic motor patterns and confirms the diurnal and regional variations in propagating pressure waves detected in the prepared colon. The study demonstrates differences between high amplitude propagating sequences and propagating sequence parameters that may have functional significance; and also, that the rectal motor complex is a ubiquitous pan colonic motor pattern.

Diagnosis and management of cricopharyngeal achalasia and other upper esophageal sphincter opening disorders

Recent literature on disorders of the upper esophageal sphincter is reviewed, including discussion of advances in measurement, diagnosis, treatment, and management. The etiology of upper esophageal sphincter disorders is summarized, along with its pathophysiology, with reference to gastroesophageal reflux disease. Medical and surgical options for improving pharyngeal clearance and minimizing aspiration are also discussed, as is the use of percutaneous esophageal gastrostomy feeding tubes.

Spatial and temporal organization of pressure patterns throughout the unprepared colon during spontaneous defecation

OBJECTIVE

The aim of this study was to examine colonic motor events associated with spontaneous defecation in the entire unprepared human colon under physiological conditions.

METHODS

In 13 healthy volunteers a perfused, balloon-tipped, 17-lumen catheter (outer diameter, 3.5 mm; intersidehole spacing, 7.5 cm) was passed pernasally and positioned in the distal unprepared colon.

RESULTS

In the hour before spontaneous defecation, there was an increase in propagating sequence frequency (p = 0.04) and nonpropagating activity when compared to basal conditions (p < 0.0001). During this hour the spatial and temporal relationships among propagating sequences demonstrated a biphasic pattern. Both the early (proximal) and late (distal) colonic phases involved the whole colon and were characterized by respective antegrade and retrograde migration of site-of-origin of arrays of propagating sequences. There was a negative correlation between propagating sequence amplitude and the time interval from propagating sequence to stool expulsion (p = 0.008).

CONCLUSIONS

The colonic motor correlate of defecation is the colonic propagating sequence, the frequency and amplitude of which begin to increase as early as 1 h before stool expulsion. During the preexpulsive phase, the spatial and temporal relationship among the sites of origin of individual propagating sequences demonstrate a stereotypic anal followed by orad migration, which raises the possibility of control by long colocolonic pathways.

Development and validation of a self-report symptom inventory to assess the severity of oral-pharyngeal dysphagia

BACKGROUND & AIMS

The aim of this study was to develop and evaluate the validity and reliability of a self-report inventory to measure symptomatic severity of oral-pharyngeal dysphagia.

METHODS

Test-retest reliability and face, content, and construct validity of a prototype visual analogue scale inventory were assessed in 45 patients who had stable, neuromyogenic dysphagia.

RESULTS

Normalized scores varied over time by -0.5% +/- 17.6% (95% confidence interval, -9.2% to 8.2%). Factor analysis identified a single factor (dysphagia), to which 18 of 19 questions contributed significantly, that accounted for 56% of total variance (P < 0.0001). After deletion of 2 questions with poor face validity and patient compliance, this proportion increased to 59%; mean test-retest change was -2% (95% confidence interval, -11% to 7%); and total score correlated highly with an independent global assessment severity score (r = 0.7; P < 0.0001). A mean 70% reduction in score (P < 0.0001) was observed after surgery in patients with Zenker's diverticulum (discriminant validity).

CONCLUSIONS

Applied to patients with neuromyogenic dysphagia, the 17-question inventory shows strong test-retest reliability over 2 weeks as well as face, content, and construct validity. Discriminant validity (responsiveness) has been demonstrated in a population with a correctable, structural cricopharyngeal disorder. Responsiveness of the instrument to treatment in neuromyogenic dysphagia remains to be quantified.

Neurogenic pathways mediating ascending and descending reflexes at the porcine ileocolonic junction

We studied the pharmacology of the neural pathways mediating the responses of ileo- and coloileo-colonic junction (ICJ) to regional distension in ten anaesthetized pigs. Using manometric pullthroughs and a sleeve sensor, we found the ICJ demonstrated sustained tone that was resistant to tetrodotoxin. Ileal distension decreased ICJ pressure by 22.2 ¿ 10.1% (11.9 ¿ 2.7-10.1 ¿ 2.6 mmHg; P=0.002) and colonic distension augmented ICJ pressure by 23.5 ¿ 8.6% (12.8 ¿ 1.5-15.6 ¿ 2.1 mmHg; P=0.02). Bethanecol and Nw-nitro-L-arginine methyl ester (L-NAME) increased ICJ pressure (P=0.002, P=0.01, respectively). Sodium nitroprusside and isoproterenol reduced ICJ pressure (P=0.004, P=0.02, respectively). In the presence of L-NAME, the early inhibitory ileo-ICJ response was abolished, while early and late inhibitory responses were abolished by further addition of propranolol but not by the addition of hexamethonium, atropine, prazosin or yohimbine. The excitatory colo-ICJ response was replaced by inhibition in the presence of L-NAME. We concluded that: (1) the porcine ICJ displays myogenic tone which is influenced by excitatory muscarinic and inhibitory nitrergic and beta adrenergic pathways (2) an inhibitory ileo-sphincteric reflex mediated by nitrergic and beta adrenergic postganglionic neural pathways (3) both excitatory and inhibitory neurogenic colo-sphincteric reflexes exist, and the excitatory pathway involves nitrergic neurotransmission.

Relationships between spatial patterns of colonic pressure and individual movements of content

The aim of this study was to examine the relationship between colonic pressure waves and movement of content. In 11 healthy subjects, pressures were recorded at 10-cm intervals from cecum to rectum for 32 h. In six subjects, transit was simultaneously measured for 8 h after direct cecal instillation of 1.5 mCi of (99m)Tc sulfur colloid. Thirty-two percent of isotope movements were related to nonpropagating activity and twenty-eight percent to propagating sequences. The extent of isotope movement related to propagating sequences (25.1 +/- 2.1 cm) was greater than that due to nonpropagating activity (12.8 +/- 0.7 cm; P = 0.0001). Propagating sequences originated significantly more frequently (P = 0.004) and propagated further (P = 0.0006) in the proximal compared with the distal colon. Only 36% of propagating sequences were propulsive of content, and compared with nonpropulsive sequences, these propagated further (41 +/- 6 vs. 27 +/- 2 cm; P < 0.05) and had a higher probability of originating proximally (P = 0.0003), a higher pressure wave amplitude (50 +/- 5 vs. 34 +/- 4 mmHg; P = 0.0001), and slower velocity (2.2 +/- 0.3 vs. 3.6 +/- 0.47 cm/s; P = 0.02). We conclude that most movements of colonic content are related to pressure waves. There is marked regional variation in the prevalence, velocity, and extent of propagation of propagating pressure wave sequences, which are an important mechanism for transporting content over long distances. The effectiveness of transport by a propagating sequence is influenced by its site of origin, amplitude, and velocity.

Cricopharyngeal myotomy does not increase the risk of esophagopharyngeal acid regurgitation

OBJECTIVE

It is not known whether cricopharyngeal myotomy predisposes to esophagopharyngeal regurgitation. Using ambulatory, dual pharyngeal, and esophageal pH monitoring before and after cricopharyngeal myotomy, our aim was to determine the effect, if any, of myotomy on the frequency of esophagopharyngeal acid regurgitation.

METHODS

We studied prospectively 18 patients who underwent cricopharyngeal myotomy for pharyngeal dysphagia (10 Zenker's, eight neurogenic dysphagia), of whom 17 agreed to undergo dual pH monitoring preoperatively, and 10 who agreed to both pre- and postoperative monitoring.

RESULTS

Symptoms of gastroesophageal reflux disease were present in 30%. Cricopharyngeal myotomy significantly reduced basal upper esophageal sphincter pressure by 49%, from 37+/-5 mm Hg to 19+/-3 mm Hg (p = 0.007). Esophagopharyngeal regurgitation was a rare event and the frequency of it did not differ between patients and healthy controls. Preoperatively, three regurgitation events in two patients did not differ from the postoperative frequency of a total of two events in the same two patients.

CONCLUSIONS

Increased esophageal acid exposure is common and esophagopharyngeal regurgitation is rare in unselected patients undergoing cricopharyngeal myotomy for pharyngeal dysphagia. Myotomy does not increase the frequency of esophagopharyngeal acid regurgitation in such patients.

Esophagopharyngeal acid regurgitation: dual pH monitoring criteria for its detection and insights into mechanisms

BACKGROUND & AIMS

A valid technique for the detection of esophagopharyngeal acid regurgitation would be valuable to evaluate suspected reflux-related otolaryngologic and respiratory disorders. The aim of this study was to derive pH criteria that optimally define esophagopharyngeal acid regurgitation and to examine patterns of regurgitation.

METHODS

In 19 healthy controls and 15 patients with suspected regurgitation, dual or quadruple pH sensors were used to monitor pharyngeal and esophageal pH. For each combination of the 2 variables, DeltapH and nadir pH, proportions of pH decreases that occurred during or independent of esophageal acidification were calculated to determine the likelihood that an individual pharyngeal pH decrease was a candidate regurgitation event or a definite artifact.

RESULTS

Overall, 92% of pharyngeal pH decreases of 1-2 pH units and 66% of pH decreases of this magnitude reaching a nadir pH of <4 were artifactual. Optimal criteria defining a pharyngeal acid regurgitation event were a pH decrease that occurred during esophageal acidification, had a DeltapH of >2 units, and reached a nadir of <4 units in less than 30 seconds. Regurgitation occurred more frequently in subjects in an upright (32 of 35) than in a supine (3 of 35 events; P </= 0.0001) position and was more frequently abrupt (synchronous with esophageal acidification) than delayed (P </= 0.05).

CONCLUSIONS

Accepted criteria for gastroesophageal reflux are not applicable to the detection of esophagopharyngeal acid regurgitation, and most regurgitation occurs abruptly and in upright position.

Relationship between terminal ileal pressure waves and propagating proximal colonic pressure waves

The relationship between propagating distal ileal and proximal colonic motor patterns has not been systematically examined in humans. Our aim was to define the relationships, if any, between prolonged propagating contractions or discrete clustered contractions and cecal propagating sequences using multiple manometric recording sites spanning the distal ileum and unprepared colon. In 14 healthy volunteers, a 17-lumen-perfused silicon catheter was positioned pernasally such that at least three recording sites lay in the ileum and the remainder in the colon. Intersidehole distance was 7.5 cm. In 271 h of recording, 30% of the terminal ileal propagating events was temporally associated with cecal propagating sequences. Significantly more prolonged propagating contractions (11 of 24, 46%; P = 0.02) were associated with cecal propagating sequences than were associated with ileal discrete clustered contractions (4 of 26, 15%). This trend was more pronounced at night. Of 159 cecal propagating sequences, 15 (9%) were preceded by an ileal propagating event. The remaining 91% was preceded by increased nonpropagating activity commencing 2 min before the cecal propagating sequence (P = 0.0002). We conclude that distal ileal propagating motor patterns are one stimulus for cecal propagating sequences, with the association being stronger for prolonged propagating contractions than for discrete clustered contractions.

Basal pressure patterns and reflexive motor responses in the human ileocolonic junction

This study aimed to determine whether a sustained high-pressure zone exists at the human ileocolonic junction (ICJ) and whether the motor responses of ICJ are consistent with sphincteric function. In 10 subjects with temporary ileostomies, a high-pressure zone was identified using a manometric pull-through with a mean pressure of 9. 7 +/- 3.2 mmHg and length of 4.8 +/- 1.2 cm. Prolonged recordings using a sleeve sensor confirmed sustained tone in the ICJ and superimposed phasic pressure waves (4-8 counts/min) occupying 35% of fasted state. A meal increased ICJ tone (P = 0.0001) and the proportion of time occupied by phasic activity to 50% (P = 0.013). Terminal ileal propagating pressure wave sequences inhibited ICJ phasic activity, and sequences not extending to the cecum reduced ICJ tone (9.0 +/- 7.2 to 5.6 +/- 6.3 mmHg; P = 0.04). Cecal distension increased ICJ tone (8.9 +/- 4.4 mmHg to 11.7 +/- 4.9 mmHg; P = 0.005). The ICJ response to ileal distension was variable and depended on resting tone at the time of distension. We conclude that the human ICJ has sustained tone with superimposed phasic activity. Tone is augmented by cecal distension or a meal and is inhibited by ileal propagating pressure waves. Response to ileal distension is variable but suggests control by descending excitatory and inhibitory pathways.

Investigative techniques in the assessment of oral-pharyngeal dysphagia

Oral-pharyngeal dysphagia is a common problem with a high morbidity and mortality. In general, it is not managed as well as esophageal dysphagia by gastroenterologists. A number of techniques are now available for the assessment of oral-pharyngeal dysphagia. However, a careful clinical assessment followed by a video barium swallow is all that is required for the diagnosis and management in the majority of patients. Pharyngeal manometry is likely to play an increasingly important role in the assessment of difficult or atypical cases in whom it can provide functional information not achievable with videoradiography alone. Videolaryngoscopy is a quick and simple way of detecting structural lesions and of assessing deglutitive airway protection. Videolaryngoscopy is non-invasive and easily performed in an office setting. Ultrasonography is a convenient way of assessing lingual function, but provides no more information than the video barium swallow. Pharyngeal scintigraphy is likely to assume a greater clinical relevance as a means of quantifying swallow efficiency and response to therapy.

Influence of altered tongue contour and position on deglutitive pharyngeal and UES function

The potential influence of altered lingual position and contour during the bolus loading phase of the swallow in mediating the swallowed bolus volume-dependent regulation of upper esophageal sphincter (UES) relaxation and opening was studied in 15 healthy volunteers using simultaneous videoradiography and manometry. A maxillary dental splint modulated tongue deformity during the early oral phase of deglutition. We examined the effect of the splint and swallowed bolus density on bolus volume-dependent changes in the timing of events in the swallow sequence and on hypopharyngeal intrabolus and midpharyngeal pressures. Peak mid-pharyngeal pressure (P = 0.001) and hypopharyngeal intrabolus pressure (P = 0.04) were significantly reduced by the splint. The normal volume-dependent earlier onset of sphincter relaxation and opening was preserved with the splint in situ. The splint significantly delayed the onset of hyoid motion and UES relaxation and opening without influencing transit times or total swallow duration. Alterations in tongue contour and position reduce intrabolus pressure and pharyngeal contraction without influencing normal bolus volume-dependent regulation of timing of UES relaxation and opening.

Predictors of outcome following cricopharyngeal disruption for pharyngeal dysphagia

The indications for, and predictors of outcome following cricopharyngeal disruption in pharyngeal dysphagia are not clearly defined. Our purpose was to examine the symptomatic response to cricopharyngeal disruption, by either myotomy or dilatation, in patients with oral-pharyngeal dysphagia and to determine pre-treatment manometric or radiographic predictors of outcome. Using simultaneous pharyngeal videoradiography and manometry, we studied 20 patients with pharyngeal dysphagia prior to cricopharyngeal dilatation (n = 11) or myotomy (n = 8), and 23 healthy controls. We measured peak pharyngeal pressure, hypopharyngeal intrabolus pressure, upper esophageal sphincter diameter, and coordination. Response rate to sphincter disruption was 65%. The extent of sphincter opening was significantly reduced in patients compared with controls (p = 0.004), but impaired sphincter opening was not a predictor of outcome. Increased hypopharyngeal intrabolus pressures (> 19 mmHg for 10 ml bolus; > 31 mmHg for 20 ml bolus) was a significant predictor of outcome (p = 0.01). Neither peak pharyngeal pressure nor incoordination were predictors of outcome. In pharyngeal dysphagia, hypopharyngeal intrabolus pressure, and not peak pharyngeal pressure, is a predictor of response to cricopharyngeal disruption. The relationship between intrabolus pressure and impaired sphincter opening is an indirect measure of sphincter compliance which helps predict therapeutic response.