Restoration of normal distensive characteristics of the esophagogastric junction after fundoplication

Abstract

Objective: To study the mechanical characteristics of the esophagogastric junction (EGJ) of postfundoplication patients and compare them with previously reported data on normal subjects and GERD patients.

Methods: Eight normal subjects, 9 GERD patients, and 8 fundoplication patients were studied with concurrent manometry, fluoroscopy, and stepwise controlled barostat distention of the EGJ. The minimal barostat pressure required to open the EGJ during the interswallow period was determined. Thereafter, barium swallows were imaged in 5-mm Hg increments of intrabag pressure. EGJ diameter and length were measured at each pressure during deglutitive relaxation.

Results: EGJ opening diameter during deglutitive relaxation was on average 0.5 cm greater in GERD patients compared with normal subjects and fundoplication patients (P < 0.05). EGJ opening pressure and opening diameter were comparable between normal subjects and fundoplication patients; however, the EGJ length was 32% longer in fundoplication patients.

Conclusions: Fundoplication restores distensibility of the EGJ to a level similar to normal subjects. Since trans-EGJ flow is related to EGJ length and EGJ diameter, these findings suggest that retrograde flow through the EGJ would be decreased by both a reduction in diameter and an increase in length of the EGJ.

FIGURE 1. The combined manometry/barostat catheter. The sleeve sensor was used for baseline recordings of the EGJ high-pressure zone. The barostat bag was cylindrical in shape and infinitely compliant in vivo. The barostat pressure required to obtain a bag diameter of 2.75 cm ex vivo was <3 mm Hg. Thus, the barostat pressure and volume required to obtain luminal distention were dependent on the mechanical properties of the surrounding structures (EGJ) and not the elastic properties of the barostat bag.

FIGURE 2. Representative images of barostat distention during deglutitive relaxation in a normal subject (A), GERD patient with hiatal hernia (B), and fundoplication (C). The diameter of the EGJ at each distensive pressure was measured from digitized images during dilute barium swallows. The narrowest point was measured as this would be the limiting diameter for flow.

FIGURE 3. Mean basal LES pressure and opening pressure during the interswallow period. Mean basal LES pressure was significantly increased in normal subjects and fundoplication patients compared with GERD patients with hiatal hernia (P < 0.05). There was no significant difference in basal LES pressure between normal subjects and GERD patients. Opening pressure during the interswallow period was significantly increased in normal subjects and fundoplication patients compared with GERD patients with hiatal hernia (P < 0.05). There was no significant difference in EGJ opening pressure between normal subjects and GERD patients. An interesting phenomenon was that EGJ opening pressure during the interswallow period was lower than basal LES pressure. This is likely due to LES relaxation secondary to barostat bag distention in the distal esophagus.

FIGURE 4. EGJ opening during deglutitive relaxation. The EGJ diameter in GERD patients with hiatal hernia was typically 0.5 cm wider at each distensive pressure compared with normal subjects and fundoplication patients. There was no significant difference in the EGJ diameter at each pressure when normal subjects were compared with fundoplication patients. The threshold pressure required to obtain an EGJ opening diameter of 1 cm was significantly increased in GERD patients (6 mm Hg) compared with normal subjects (12.5 mm Hg) and fundoplication (13.5 mm Hg) patients (P < 0.05).