The upper esophageal sphincter in the high-resolution manometry era.

Background The evaluation of the upper esophageal sphincter (UES) has been neglected during routine manometric tests for decades, mostly due to the limitations of the conventional manometry which were eventually overcome by high-resolution manometry (HRM). Methods This study reviewed the current knowledge of the manometric evaluation of the UES in health and disease in the HRM era. Results We found that HRM allowed more precise measurements, in addition to the parameters as compared to conventional manometry, but most of them still need confirmation of the clinical significance. The parameters used to evaluate the UES were extension, basal pressure, residual pressure, relaxation duration, relaxation time to nadir, recovery time, intrabolus pressure, and deglutitive sphincter resistance. UES may be affected by different diseases: achalasia (UES is hypertonic with impaired relaxation), gastroesophageal reflux disease (UES is short and hypotonic), globus (UES ranges from normal to impaired relaxation to hypertonic), neurologic diseases (stroke and Parkinson - UES is hypotonic in early-stage to impaired relaxation in end-stage disease), and Zenker's diverticulum (UES has impaired relaxation). Conclusion This review shows that UES dysfunction is part of several disease processes and that the study of the UES is possible and valuable with the aid of HRM.