A study of dysphagia symptoms and esophageal body function in children undergoing anti-reflux surgery

Abstract

Background: The role of high-resolution esophageal impedance manometry (HRIM) for establishing risk for dysphagia after anti-reflux surgery is unclear. We conducted a prospective study of children with primary gastroesophageal reflux (GER) disease, for whom symptoms of dysphagia were determined pre-operatively and then post-operatively and we examined for features that may predict post-operative dysphagia.

Methods: Thirteen children (aged 6.8-15.5 years) undergoing work-up prior to 360o Nissen fundoplication were included in the study. A dysphagia score assessed symptoms at pre-operative study and post-operatively (mean 1.4 years). A HRIM procedure recorded 5-ml liquid, 5-ml viscous and 2-cm solid boluses. We assessed esophageal motility, esophago-gastric junction (EGJ) morphology, EGJ contractility and pressure-flow variables indicative of bolus distension pressures and bolus clearance pressures. A composite pressure-flow index score was also derived.

Results: Pre-operative pressure-flow index was positively correlated with post-operative dysphagia score (viscous bolus r = 0.771, p < 0.005). Of three variables that comprise the pressure-flow index, the ramp pressure measured during bolus clearance was the main driver of the effect seen (viscous bolus r = 0.819, p < 0.005).

Conclusions: In order to mitigate symptoms in relation to anti-reflux surgery, dysphagia symptoms and esophageal function need to be pre-operatively assessed. In patients with normal motility, an elevated pressure-flow index may predict post-operative dysphagia.

Keywords: Gastroesophageal reflux; diagnosis; dysphagia; fundoplication.

Figures

Figure 1.

Derivation of pressure-flow metrics. Automated analysis was applied to each swallow within a region of interest (see inset Clouse plot, lower right). (a) A pressure topography iso-contour plot with superimposed lines showing the position of the nadir impedance (thick purple line; indicating peak distension) and contractile peak (thick red line) over time. The analyst fine-adjusted the landmarks, paying particular attention to the transition zone (TZ), the contractile deceleration point (CDP; yellow star) and crural diaphragm (CD). (b) Intrabolus distension pressure during bolus transport was determined by pressure at nadir impedance which was measured along the esophagus. The average distension pressure (DP) was determined within three anatomical regions approximating the different phases of bolus transport. These were accommodation (DPA, pressures proximal to TZ), compartmentalized transport (DPCT, pressures TZ to CDP) and esophageal emptying (DPE, pressures from CDP to CD). (c) Effectiveness of bolus clearance was determined from TZ to CDP based on the impedance ratio (IR = nadir impedance divided by impedance at contractile peak). A higher IR equates to less effective bolus clearance. (c) Bolus flow latencies and clearance pressures were determined based on the pressure and impedance recordings at the CDP level. Swallow to distension latency (SDL) was measured from swallow onset to nadir impedance and distension to contraction latency (DCL) from NI to luminal clearance/closure corresponding to recovery of impedance to 50% from baseline (see plot lower left). The ramp pressure (RP) was determined within the distal esophagus (sensors within distal 25% of the TZ to CDP length) and defined by the mean gradient of pressure change over time from maximum distension (NI) to luminal closure (see plot lower middle, note impedance presented relative to baseline and reversed in direction). Variables DCL, DPE and RP were combined to derive the pressure-flow index (PFI) composite score.

Figure 2.

Reflux monitoring findings in six patients investigated by pH or pH-MII probe pre- and post-operatively due to symptom recurrence. a) Total number of acid GER episodes, b) reflux index (%time pHt- and p-value shown. Total liquid GER data (in c) are incomplete for four patients due to pH-MII not being performed pre-operatively.

Figure 3.

Pre-operative recordings and pressure-flow data from example cases: Case 1 with pre-operative dysphagia that resolved post-operatively and Case 2 with significant persisting dysphagia. Tracings are based on recordings of 5-ml viscous bolus swallows. (a–e) Esophageal pressure topography of the distal esophagus with axial location of contractile deceleration point (CDP) marked. (b and f) Pressure (black) and impedance (purple) profiles over time at the level of the CDP. (c and g) Pressure (black) and the impedance relative to baseline (purple) for the period 1 s before to 0.5 s after the 30-mmHg iso-contour (the direction of impedance change is reversed compared to b and f; 100% is pre-swallow baseline, 0% is maximum distension and 50% defines luminal closure). Note that the impedance-defined luminal closure (50%) occurs relatively later in time for Case 2, resulting in greater clearance pressures being generated as the lumen closes. (d and h) The relationship between relative impedance (x axis) and pressure (y axis) over time. As seen in d, from Case 1, the lumen opens and then closes without any change in clearance pressure (known as isotonic contraction). As seen in h, from Case 2, the lumen opens and then closes with clearance pressures increasing (known as auxotonic contraction). (i) Bar charts of patient Dakkak scores and the average data for the relevant pressure-flow metrics derived for liquid and viscous bolus swallows. Note, markedly higher clearance pressures (RP and CP) for Case 2.