Tracheal growth after slide tracheoplasty

Abstract

Objective: Our goal was to investigate the effects of slide tracheoplasty on tracheal growth in newborn piglets. Methods: Slide tracheoplasty was performed on normal trachea ( n = 6) and a model of tracheal stenosis resembling that seen in infants ( n = 6). After division of the trachea at its midportion between the second cartilaginous ring above and the right upper lobe takeoff below (around 23 rings), the proximal and distal segments were incised vertically on opposite anterior and posterior surfaces and reconstructed together. Results: The reconstructed tracheas lengthed and their cross-sectional areas enlarged linearly at a rate of 0.94 cm per month and 1.55 mm 2/kg, respectively, as the piglets grew over a 6-month period from 4.7 ± 0.6 to 64.4 ± 5.7 kg (± standard deviation). Growth was not different between the two studied groups. There was no narrowing or late restenosis. The mean anastomotic cross-sectional area was overall 1.63 ± 0.28 times larger (range 1.2 to 2.7) than the cross-sectional area of the unreconstructed trachea. When the animals were put to death, all tracheal lumina were completely lined with normal respiratory epithelium and all layers were histologically intact; anastomotic trachealis muscles contracted less ( p < 0.001) but relaxed similarly to those muscles lining normal tracheas. Tracheal blood supply was macroscopically and microscopically normal in both groups; however, newborn piglets had an almost twofold increased number of intramural capillary vessels as opposed to adult pigs ( p < 0.001). Conclusions: Results suggest that slide tracheoplasty is not limited by the length of stenosis, provides a permanent enlargement of the cross-sectional airway diameter, does not compromise tracheal vascular supply, and does not impair tracheal growth as somatic growth continues. (J Thorac Cardiovasc Surg 1997;113:558-66)