Long-term growth of a vascularized auricular perichondrocutaneous flap in laryngotracheal reconstruction. 
This study addresses the potential for ongoing cartilage proliferation after repair of laryngotracheal stenosis with vascularized perichondrium.  We randomly assigned 32 New Zealand white rabbits to 1 of 3 groups: group 1 (early cartilage growth, n = 10), group 2 (long-term cartilage growth after pedicle ligation, n = 11), and group 3 (long-term cartilage growth without pedicle ligation, n = 11).  Bilateral auricular perichondrocutaneous flaps were elevated and transposed into full-thickness anterior tracheal wall or anterior cricothyroid membrane defects.  Six weeks after elevation of the flap, animals were randomly assigned to undergo ligation of either the right or left vascular pedicle (group 2), with the contralateral auricular flap used as a matched control (group 3).  Neochondrogenesis was present at 6 weeks in group 1 (0.74 +/- 0.14 mm, n = 12 ears).  Cartilage thickness did not differ between groups 2 and 3 one year after ligation of the vascular pedicle: group 2 (0.48 +/- 0.24 mm, n = 18) versus group 3 (0.42 +/- 0.12 mm); P > 0.05.  We conclude that in the rabbit model, chondrogenesis did not appear to be ongoing and did not result in late stenosis of the reconstructed airway.  Furthermore, delayed ligation of the vascular pedicle neither inhibited nor stimulated cartilage proliferation.