Experimental validation of laryngotracheal growth and recurrent laryngeal nerve preservation after partial cricotracheal resection in a growing rabbit model

Methodological Approaches for Vocal Folds Experiments in Laryngology: A Scoping Review

OBJECTIVE

The aim of this study was to describe the methodological approaches adopted in experimental researches in laryngology intervention studies.

METHODS

The study was performed as a scoping review using the electronic databases Medline (PubMed), Web of Science, Embase, BioMed Central and SCOPUS. These databases were manually searched from 1995 (or its inception) until the most recently published articles in June 2022. The inclusion criteria were as follows: a) studies performed with animal models in voice and/or larynx therapy, intervention and/or surgery; b) studies with participant populations composed with animals; c) studies containing original research; d) studies performed with at least one objective measurement for treatment and or intervention; e) studies reporting at least one method of larynx intervention; and f) publications written in English, Spanish or Portuguese. The exclusion criteria were as follows: a) studies considering without any objective intervention and or treatment; b) studies without animal models; and c) studies that reviewed articles or books. These criteria were set to increase inter-study comparability.

RESULTS

There were found 26 studies that showed that in experimental laryngology. There were retrieved four main characteristics in the retrieved studies. It was observed five major groups of experimental models used for assessing vocal folds: dog (38.5%), rat/mouse (23,1%), pig (23.1%), rabbit (19.2%), human (11.5%), and sheep (3.8%). In addition, three characteristics were observed: sample (up to 20 subjects 88.5%), type of surgery/intervention (100%) and duration (up to 30 days 61.5%).

CONCLUSION

In experimental laryngology, the state of the art is grounded on mainly in dog, rat and pig in vocal folds assessment. Up to 20 subjects, surgery/intervention and experimental trial lasting no more than 30 days are frequent methodological approaches in this research field.

Minimally Invasive Neck Surgery: An Animal Model Study

Background: Minimally invasive surgery (MIS) is replacing conventional surgery as the "gold standard" in different surgical areas. Although cervical MIS is already accepted in the adult population, its use in children is still new and controversial. The natural obstacles to this approach are the absence of a natural cavity, with the inherent complications of creating one artificially, and the limited existing workspace especially in pediatric patients. All endoscopic techniques in the field of neck surgery try to live up to the high cosmetic expectations and the transoral cervical approach as a natural orifice surgery technique excels at it. Aim: Besides the goal of feasibility, we aim to report on the pitfalls of this approach, by using an experimental rabbit model for minimally invasive thyroidectomy. Materials and Methods: Transoral endoscopic thyroidectomies using a vestibular approach were performed in 10 anesthetized rabbits. All surgeries were video recorded. The surgical time, anatomy identified, difficulties, and intraoperative complications were documented. Results: Through one trocar in the vestibular area and two lateral stab incisions, it was possible to create a working space and to reach the peritracheal area. Total thyroidectomies were completed in the 10 animals with a mean operative time of 51 minutes. In all of them we were able to identify the fascial spaces of the neck and the major vessels. During surgery, the lack of space required surgical gestures to be very precise, soft, and gentle. There were 2 cases with a small amount of bleeding and one mild trachea laceration during the procedure, but none of them required suspension or conversion to an open procedure. Animals were euthanized immediately after the surgical procedure. Conclusions: The vestibular approach seems to be a feasible technique to access pediatric neck pathology. Despite the differences in the cervical anatomy, the limited workspace of the rabbit model perfectly matches the requirements of a pediatric training model.