Variations of the anterior cricoid split: the effect on airway cross-sectional area in the rabbit

The anterior cricoid split (ACS) operation has been documented as a successful treatment for the difficult-to-extubate infant or child. The exact mechanism by which this operation is successful is still being investigated. In an effort to further elucidate the effect of the ACS procedure on the subglottic airway, four groups of rabbits were studied. Both size and shape of the subglottic area after surgical manipulation were evaluated, comparing control rabbits with ACS, anteroposterior cricoid split (A-PCS), and partial cricoid split with sparing of soft-tissue lining (partial ACS). The animals were sacrificed 4 weeks after surgery, and the larynxes were harvested. Analysis showed a significant enlargement of the subglottic lumen in all experimental groups as measured at the inner lamina of the cricoid cartilage. However, the true subglottic lumen was significantly enlarged only in the ACS group. Findings showed that true enlargement of the subglottic lumen was limited in all experimental groups to increased thickness in the soft-tissue lining of the subglottic lumen, which was most marked in the A-PCS group. A significant change in subglottic lumen shape occurred in the A-PCS group as well. These results suggest the A-PCS should be approached clinically with caution when a stent is not used.