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[12]
Figure 2: The tracheal blood supply is segmental. Branches from the
inferior thyroid, subclavian, internal thoracic, innominate, superior and
middle bronchial arteries form two lateral longitudinal anastomoses to
supply the anterolateral trachea. These anastomoses give off transverse
branches, which penetrate through the intercartilaginous ligaments
to feed the submucosal capillary plexus. Cartilage is nourished via
diffusion from this plexus. The posterior membranous trachea has an
independent vascular supply derived from the oesophageal branches of
the above-mentioned large neck vessels
Definitions
[5]
The term prelamination was defined by Pribaz and Fine
to describe the implantation of tissue or another device
into a vascular territory without manipulation of the
blood supply. In a second stage, the construct with its
blood supply can be transferred as a pedicled or free
flap. As such, it is possible to create a multilayered,
vascularized flap. Prelamination is not to be confused
[6]
with prefabrication, introduced by Yao, which is the
implantation of a vascular pedicle into a new territory.
After neovascularization, tissue in this territory can be
transferred based on the implanted pedicle.
Figure 1: Human vs. rabbit trachea. (a) Human trachea measures 10
cm ± 9 cm; [10] (b) rabbit trachea measures on average 6.5 cm; (c)
human cartilage rings comprise two-thirds of tracheal circumference Heterotopic placement of the trachea refers to the
vs. 90% in rabbits (d). The blue (c) and green (d) arrows represent the temporary placement of the tube in an anatomical
trachealis muscle; (e and f) Masson’s trichrome stain: human trachea (e) location other than its normal position in the neck, for
contains more submucosal glands, compared to the better-developed example in the lateral thoracic area. When the trachea is
submucosal capillaries in rabbits (f)
transplanted to its anatomically correct position in the
neck, it is referred to as orthotopic position.
following a period of heterotopic revascularization in
the lateral thoracic fascia. This animal model has become Why rabbits?
the gold standard of the authors for research regarding Numerous advantages are associated to working with
tracheal transplantation. As a result of this benchwork, rabbits. Rabbits have a long cervical trachea, allowing for
the first human allogenic trachea was transplanted easy access to the tube and segmental transplantation.
with withdrawal of immunosuppression in 2008. Also, in contrast to larger animals such as pigs or sheep,
[2]
Since then, 5 more patients have been transplanted in rabbits are more readily accessible for research purposes
our center. [3,4] This clinical breakthrough, in addition to and are more convenient to manage. Rabbit cell-surface
ongoing translational research in the rabbit model, has markers for recognition by the immune system have been
contributed to the authors’ experience in the field. To mapped out. These rabbits major-histocompatibility
[7]
date, over 200 tracheal transplantations in the rabbit have complexes are referred to as Rabbit Leukocyte Antigens.
been performed. The authors wish to share their 20 years Rabbits are phylogenetically closer to primates and
of experience with this versatile model by discussing have a more diverse genetic background than inbred
the key elements of tracheal surgery in the rabbit, by and outbred rodent strains. [7-9] This makes the model
reviewing key elements of the tracheal anastomosis a better overall approximation to humans, mimicking
and the harvest of the lateral thoracic artery flap, and human genetic diversity more accurately. Moreover, the
by giving practical examples. The importance of proper tracheal anatomy of humans resembles that of the rabbit
revascularization of the construct is emphasized, as it is closely. It is also possible to perform tracheoscopy as a
the authors’ opinion that it is paramount in obtaining a monitoring tool following transplantation, and to obtain
successful tracheal transplantation. an adequate tracheal length for epithelial cell-cultivation.
224 Plast Aesthet Res || Volume 3 || July 7, 2016