Mechanisms of esophago-pharyngeal acid regurgitation in human subjects.
UNLABELLED
Esophago-pharyngeal regurgitation is implicated in various otolaryngologic and respiratory disorders. The pathophysiological mechanisms causing regurgitation are still largely unknown.


AIM
To determine the principal mechanisms behind esophago-pharyngeal regurgitation.


METHODS
We studied 11 patients with extra-esophageal GORD symptoms in whom esophago-pharyngeal acid regurgitation had previously been demonstrated using ambulatory, dual (pharyngo-esophageal) pH metry (>2 episodes/day using previously validated pH-metric criteria). Patients underwent continuous, 24 hr, stationary monitoring of pharyngo-esophageal manometry and dual (pharyngeal and esophageal) pH recordings. They were intubated with a 14-channel manometric assembly incorporating 2 sleeve sensors monitoring the upper and lower esophageal sphincters simultaneously. A dual pH catheter recorded pH signals 2 cm above the UES midpoint and 7 cm above the LES midpoint.


RESULTS
A total of 32 episodes of spontaneous esophago-pharyngeal acid regurgitation were recorded. All episodes occurred in the upright posture and 91% occurred within 3 hrs post-prandium. All regurgitation events were associated with a relaxation of the UES, which were classified as transient non-swallow related relaxations in 29 (91%) and swallow-related in the remaining 3 (9%). Straining was an additional associated factor in 41% of regurgitation events, but strain alone was not sufficient to cause esophago-pharyngeal regurgitation.


CONCLUSION
Some form of active UES relaxation is necessary for regurgitation to occur. The dominant mechanism underlying esophago-pharyngeal acid regurgitation is the non-swallow related, transient UES relaxation.


LEVEL OF EVIDENCE
N/A.