[Morphology of cricopharyngeal muscle under suspension laryngeal endoscope]

To observe the morphologic features of cricopharyngeal muscle (CPM) under suspension laryngeal endoscope.

This prospective study was conducted on a series of 100 consecutive patients who undergone endoscopic microlaryngeal surgery with intubation general anesthesia. The suspension laryngoscope was introduced down to postcricoid area approaching esophageal inlet. By lifting the larynx with the laryngoscope, the mucosa-covered cricopharyngeal muscle was easily identified as the mound of tissue just at the posterior pharyngeal wall. The image of cricopharyngeal muscle under the laryngoscope was saved.

In 94 out of 100 patients, CPM could be visualized with laryngoscope. In the other 6 patients, both CPM and glottic could not be exposed because of cervical vertebra stiffness and obesity. According to the image of CPM under the laryngoscope, the shape of the CPM was divided into three types. It was named for flat type in which there was no mound of tissue visible at the posterior pharyngeal wall and esophageal cavity could be visible completely, semi-bar type in which there was a bar at the posterior pharyngeal wall and partial esophageal cavity could be visible and full-bar type in which the bar contact esophageal anterior wall and esophageal cavity could not be visible. There were 14(14.9%) patients as flat type, 59(62.8%) as semi-bar type and 21(22.3%) as full-bar type. No significant difference was found between adults group and the aged (≥ 65 years old) group (χ(2) = 1.224, P = 0.747) and reflux associated group and non-reflux associated group respectively (χ(2) = 5.252, P = 0.072).

The CPM could be well exposed in most of the patients with suspension laryngeal endoscope. It provides anatomy basis for endoscopic cricopharyngeal myotomy.