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incision to the neck incision is freed subdermally, creating observed. Three rabbits exhibited flap congestion, which
enough width in the tunnel to prevent flap congestion. could be corrected by widening the subcutaneous tunnel
The flap is fixated in the neck to avoid dislocation. The (1.5%, total n = 200).
incisions are closed with subcutaneous interrupted and
intradermal running sutures with buried knots to prevent Limitations
wound dehiscence secondary to biting. Although rabbit tracheal anatomy resembles human
anatomy closely, the rabbit is not a large animal
Orthotopic transfer model. Rabbit trachea contains more submucosal
Optimal revascularization of autologous trachea vascular structures, as compared to the more glandular
is achieved after fourteen days of heterotopic submucosa of human trachea [Figure 1]. Furthermore,
prelamination. [23-25] At this point, the trachea and its the rabbit trachealis muscle encompasses only 10% of
flap can be transferred to their orthotopic position in the tracheal circumference, in contrast to 30% in humans.
the neck [Figure 9]. Upon inserting the construct, it is Also, it is postulated that rabbits have better developed
important to minimize the amount of tension placed on longitudinal anastomoses along the lateral tracheal wall,
the flap. This tension can potentially create respiratory as is the case for cats and dogs. Another difficulty
[12]
distress secondary to kinking of the tube. Proximal and in the use of rabbits for study is the application of
distal anastomoses are performed as described earlier.
immunohistochemistry markers in rabbit tissue. Rabbits
are commonly used to produce monoclonal antibodies
Postoperative care against rodent or human epitopes. As a consequence,
Rabbits are awakened from anesthesia with extra appropriate rabbit-specific antibodies are more difficult
oxygen via mask ventilation and kept warm. Adequate to find, as they are often produced in the rabbit itself. As
analgesia is provided postoperatively and enrofloxacin in humans, a disadvantage of the rabbit’s lateral thoracic
is administered in the drinking water upon indication. artery is its routinely small caliber, which makes it more
Tracheoscopy is performed weekly or in case of respiratory
distress (2.9 mm, 0°, rigid endoscope, Karl Storz). difficult for free flap transfer.
PRACTICAL EXAMPLES CONCLUSION

This review summarizes our experience with the rabbit
Orthotopic prefabrication as a versatile model for tracheal transplantation research.
To perform studies on vascularized autologous trachea, The advantages of working with rabbits, the anatomy
a native tracheal segment can be wrapped with lateral
thoracic fascia prior to manipulation [Figure 10]. After of the rabbit trachea and the reliability of the lateral
thoracic artery flap make this model the authors’ gold
two weeks of prefabrication, the autologous tracheal standard. Additionally, the pedicled lateral thoracic
segment is vascularized and can be manipulated safely
on the lateral thoracic pedicle. artery flap can be used for various reconstructive
procedures and prelamination studies. The data
Heterotopic prelamination presented in this review represent the fundaments of
Regular wound controls are planned during heterotopic ongoing translational research in our center over the past
vascularization. Every three days the skin is opened twenty years. Because of the segmental blood supply
and the construct is exposed under general anesthesia. of the trachea, it is unfeasible to transplant the organ
As such, intraluminal tissue-ingrowth and mucus- together with a well-defined vascular pedicle. As such,
accumulation are avoided, thereby preventing fibrosis the main challenge of successful tracheal transplantation
and infection. is the creation of a new blood supply. In clinical practice,
revascularization of human allotrachea in the radial
For ethical reasons, if orthotopic inset is not planned, forearm fascia was enhanced by making incisions in
[3]
two lateral thoracic artery flaps can be used per rabbit to the intercartilaginous ligaments. To further enhance
minimize the number of animals used [Figure 11]. vascularization of transplanted tracheae, the authors are
currently investigating pro-angiogenic strategies in their
COMPLICATIONS AND LIMITATIONS standardized rabbit model.

Complications Financial support and sponsorship
Minor complications such as seroma formation can This work was supported by the predoctoral fellowship
be treated by aspiration of the region of fluctuance. of the Research Foundation Flanders (FWO) of Dr. Margot
Wound dehiscence is prevented by using intradermal Den Hondt.
running sutures with buried knots, and by transferring
the construct to the neck during heterotopic Conflicts of interest
revascularization. To date, no flap failures have been There are no conflicts of interest.
Plast Aesthet Res || Volume 3 || July 7, 2016 229