Influence of age on resistance to distraction after tracheal anastomoses in dogs: An ex vivo study

Abstract

Objective: To determine the influence of age on the ability of tracheal anastomoses to sustain distraction in dogs.

Study design: Ex vivo study.

Sample population: Cadaveric canine tracheae (n = 16).

Methods: Tracheae were harvested from the cadavers of 8 immature and 8 adult dogs. Each trachea underwent end-to-end annular ligament anastomosis with a simple continuous pattern with 2-0 polypropylene on a taper cut needle. The constructs were tested to failure in distraction, with a tensiometer set at a drop head speed of 50 mm/min, as determined by preliminary testing. Failure was defined by tissue pullthrough or suture material failure. The force and elongation at failure were compared between age groups.

Results: The median age was 5.5 months (4-7.5 months) in immature dogs and 8.25 years in adult dogs (2-18 years) Tracheal anastomoses failed at lower forces (44.91 ± 59.03 N) but sustained more elongation (39.75 ± 5.45%) in immature dogs than in adult dogs (149.31 ± 45.36 N, P = .007 and 30.57 ± 7.19%, P = .0012, respectively). Tissue apposition was not achieved in 4 specimens each in immature and adult dogs, respectively.

Conclusions: The technique used for tracheal anastomoses in this study failed at lower loads but sustained more elongation when performed in immature dogs.

Clinical significance: Immature dogs may be able to withstand longer tracheal resection than adult dogs but reinforcement techniques seem mandatory to improve resistance to tension. Alternative anastomosis techniques should be considered to improve tissue apposition.