Tracheal growth after resection and anastomosis in puppies.

Tracheal morphology, morphometric changes, and growth and histologic changes were studied in puppies submitted to tracheal resection and anastomosis. Fifteen mongrel puppies about 12 weeks old and weighing on an average 5.5 kg were operated under general anesthesia using fluothane. A median cervicotomy incision was made in ten puppies (experimental group, EG) and the proximal 14 tracheal rings were resected (average length 5.08 cm or about 35% to 38% of total tracheal length). One layer anastomosis was done using vicryl 4.0 maintaining the average tension of 1,450 g. Five puppies (control group, CG) were submitted to tracheal transection and anastomosis and the following parameters were studied. Tracheal morphology the trachea of the EG was a rounded triangle whereas in the CG it was oval in shape, there was increase in the intercartilageneous spaces in the EG, no granulation tissue was present, two mucous webs were seen in the EG and one in the CG. Morphometric changes average tracheal length EG 13 cm, CG 17.7 cm, intercartilagenous space EG 3.08 mm, CG 1.3 mm, intercricothyroid space EG 1.2 cm, CG 0.53 cm, sagittal and transverse tracheal thickness at the anastomosis EG 2.6 and 3.3 mm, CG 2 and 1.5 mm, sagittal and transverse diameter reduced on an average 2 mm in EG. Histology Moderate fibrosis was found at the level of anastomosis with no modification of chondrocytes at the cartilagenous rings in the EG. Even with high anastomotic tension, the dogs had normal tracheal growth without stenosis; the sagittal and transverse growth at the anastomosis in the EG was 90% and 85%, respectively, when compared with the CG.