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Use of the Peritracheal Fold in the Dog Tracheal Transplantation Model
Patrick J. Gannon, PhD;
Peter D. Costantino, MD;
Edgar A. Lueg, MD;
John M. Chaplin, MB, ChB;
Margaret S. Brandwein, MD;
Philip J. Passalaqua, MD;
Lawrence J. Fliegelman, MD;
Jeffrey T. Laitman, PhD;
Samuel Marquez, MPhil;
Mark L. Urken, MD
Arch Otolaryngol Head Neck Surg. 1999;125:959-963.
Objective To investigate the technical aspects of the canine model of human tracheal transplantation for potential application to reconstruction of extremely long tracheal defects (>10 cm).
Design In phase 1, long tracheal segments were skeletonized and pedicled with the thyroid glands, cranial thyroid arteries and veins, and internal jugular vein branches. The segments were elevated completely, attached to the vascular pedicle only, and replaced with primary tracheal anastomoses. In phase 2, long segments were elevated along with a diffuse soft tissue "blanket" that envelops the trachea and thyroid glands. Because this study was designed to primarily address, in situ, tracheal perfusion territories of a cranially located vascular pedicle, microvascular anastomoses were not conducted.
Subjects Two small-bodied beagles (10-15 kg) and 5 large-bodied mixed-breed dogs (20-30 kg) were humanely killed 2 to 41 days after surgery, and anatomic and histological analyses were conducted.
Results Unlike that of humans, the thyroid gland complex of dogs is not intimately associated with the trachea but is conjoined with a peritracheal soft tissue "fold." Within this fold, blood is transmitted to the trachea via a diffuse, segmental vascular plexus. In phase 1, pronounced tracheal necrosis occurred within 2 to 5 days. In phase 2, extremely long tracheal segments (10-12 cm), based only on a cranially located pedicle, were still viable at 2 to 6 weeks.
Conclusions Preservation of the "peritracheal fold" in the dog model of tracheal transplantation is critical to the onset and maintenance of vascular perfusion in a long tracheal segment. Furthermore, the use of large-bodied dogs is necessary to provide for a usable venous efflux component.
From the Departments of Otolaryngology (Drs Gannon, Costantino, Passalaqua, Fliegelman, and Urken), Pathology (Dr Brandwein), and Cell Biology and Anatomy (Dr Laitman and Mr Marquez), Mount Sinai School of Medicine, New York, NY; Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Ontario (Dr Lueg); and Department of Otolaryngology–Head and Neck Surgery, Dunedin Hospital, Dunedin, New Zealand (Dr Chaplin).
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