The anterior cricoid split in puppies

The intrinsic response of the cricoid cartilage to vertical division

The explanation for the separation in the cricoid cartilage after the anterior cricoid split procedure has been a matter of speculation. Whether it is caused by extrinsic factors such as stenting, contraction of laryngeal muscles, fibrosis, or whether it is due to the intrinsic nature of the cricoid cartilage itself has yet to be defined. Whole organ in vitro cultures of juvenile gerbil cricoid cartilages were utilized to study the intrinsic response of cricoid cartilage to anterior vertical division. Our results showed the cricoid cartilage to immediately separate, and that separation to markedly increase during whole organ culture. These results suggest that while extrinsic factors may modify the gap after the anterior cricoid split procedure, the intrinsic nature of the cricoid cartilage itself results in the gap formation.

Expansion of the infant subglottis by external cricoid distraction: an animal model

A technique is described to expand the subglottis by anterior cricoid split (ACS) combined with external cricoid distraction (ECD) using a posterior belly of digastric muscle sling. This technique was used on 5-week-old rats that were killed 6 weeks after surgery, and the larynges were examined histologically and compared with those of rats who underwent ACS alone. Information was available from ten animals in the ECD group and five in the ACS alone group. Separation of the cut ends of the cricoid was found to be maintained in all animals after ECD, the gap having been filled by fibrous tissue lined by respiratory epithelium. A lesser degree of cricoid separation was seen in the animals that underwent ACS alone.

Independent effects of denervating the cricothyroid muscle and stenting on the anterior cricoid split: canine model

The anterior cricoid split (ACS) has gained in popularity since its introduction in 1980, for the treatment of the difficult to extubate child. The procedure allows a successful extubation and avoids a tracheotomy about 75% of the time. How the ACS allows extubation remains poorly understood. Animal research has shown that in the canine model the ACS results in a gap in the cricoid cartilage with a subjective increase in the subglottic space (Senders and Eisele, 1978). This gap in the cricoid cartilage develops whether or not an endotracheal tube stent is used. This experiment was designed to quantitatively evaluate the effect of the ACS on the subglottic space with or without the use of the stent, and to evaluate the effect of the cricothyroid muscle on the ACS procedure. The results show that the ACS does result in an increase in the subcricoid space, and that the use of an endotracheal tube stent does result in a larger increase. The cricothyroid muscle has a strong immediate effect on the gap in the cricoid cartilage, which is eliminated by sectioning the external laryngeal nerve. The long-term effects of sectioning the external laryngeal nerve on the gap in the cricoid cartilage were not conclusive.

The anterior cricoid split: the Children's Hospital of Philadelphia experience

The anterior cricoid split procedure (ACS) is an alternative to tracheotomy in selected infants with subglottic stenosis. From February 1983 to October 1987, 26 children underwent ACS at the Children's Hospital of Philadelphia. All children had subglottic stenosis. Six children had previously undergone tracheotomy. A successful outcome, allowing extubation or decannulation, correlated only with decreased pre-operative intubation time and was achieved in 73% of these patients. A failed ACS had little adverse affect on the subsequent management of these children.