Breaking strength of native and sutured trachea. An experimental study on sheep trachea

Tracheal anastomoses are, even more so than other sutures, often only possible to prepare under tension and thus in danger of breakage. No information is available regarding native tracheae and freshly sutured tracheae. For this reason, our objective was to examine the tensile strength of native tracheae and compare it with freshly sutured specimens. Fresh tracheae were collected from the local slaughterhouse within 30 min of slaughter. With the help of a suitable holding device, 24 fresh tracheae were mounted on a material testing machine and stretched to breaking point, during which the force and distance required were recorded. The same study was carried out on each 10 freshly anastomosed tracheae using three different suturing techniques. The mean value of the maximum force required for native tracheae was 198 N. With continuous suturing (polypropylene), a mean value of 171 N was attained, and with single interrupted suturing (polydioxanone and polyglactin 910), 123 N, respectively, 108 N. Differences between the groups proved to be highly significant. With respect to the mechanical strain from traction, the continuous suture proved to be statistically identical to native tracheae, whereas single interrupted sutures revealed a considerably lower stability under burden. Therefore, the continuous suture is of advantage in respect of the mechanical strain from traction and the suture protection of tracheal anastomoses. Further studies with differing survival times in vivo with this method provide insight into the stability of tracheal anastomoses during the healing process.