AAHS ASPN ASRM - 2013 Annual Meeting - American Association ...

ASRM Concurrent Scientific Paper Presentatons C-1
A New Composite Tissue Allograft Transplantation Model for Reconstruction of the Head and Neck Defects and
Long Term Survival Permitted by Donor Specific Chimerism Under Low Dose Cyclosporine A Treatment
Institution where the work was prepared: Cleveland Clinic, Cleveland, OH, USA
Yalcin Kulahci; Aleksandra Klimczak; Maria Siemionow; The Cleveland Clinic Foundation
Background:
Extensive head and neck deformities including bone and soft tissue defects are always challenging for reconstructive surgeons. The purpose of this study was
to extend application of the face/scalp transplantation model in rat by incorporation of the vascularized mandible, masseter and tongue, based on the same
vascular pedicle, as a new reconstructive option for extensive head and neck deformities with large soft and bone tissue defects.
Methods:
A total of 12 composite osseomusculocutaneous hemiface/mandible-tongue transplantations were performed in two experimental groups. Group 1 isotransplantation
between Lewis rats served as control without treatment (n=6). Group 2 (n=6) composite hemiface/mandible-tongue transplants were performed
across MHC barrier between Lewis-Brown Norway (LBN, RT11+n) donors and Lewis (RT11) recipients. Hemifacial flaps including hemimandibular bone, masseter
muscle and tongue were dissected on the same pedicle of external carotid artery and jugular vein and were transplanted to the donor inguinal region.
All allogenic transplant recipients received 16mg/kg/day of CsA monotheraphy tapered to 2 mg/kg/day and maintained at this level thereafter. All animals were
monitored for sign of allograft rejection such as erythema, edema, hair loss, desquamation. Flap angiography and CT scan evaluated allograft viability. Flow
cytometry assessed donor-specific chimerism for MHC class I- RT1n antigen. H&E staining revealed bone histology, hemotopoietic activity and tested inflammatory
response and grade of allograft rejection.
Results:
Isograft controls survived indefinitely. Six hemiface/mandible-tongue allotransplants survived up to 200 days (still under observation). Flap angiography demonstrated
intact vascular supply to the bone. No signs of rejection and no flap loss were noted. CT scan and bone histology confirmed viability of bone components
of the composite allografts. Viability of tongue was confirmed by pink color, bleeding after puncture and histology. H+E staining determined the presence
of viable bone marrow cells within transplanted mandible. Donor-specific chimerism at day 100 posttransplant was established for by presence of donor
T-cells (2.7% CD4/RT1n, 1.2% CD8/RT1n) and B-cells (11.5% CD45RA/RT1n).
Conclusions:
We have introduced a new model of composite osseomusculocutaneous hemiface/mandible-tongue allograft transplant. Long-term allograft acceptance was
accompanied by presence of donor specific chimerism supported by vascularized bone marrow transplant of the mandibular component. This model may serve
as a new reconstructive option for coverage of the extensive head and neck deformities involving large bone and soft tissue defects performed in one-stage
surgical procedure.
Potential Approaches to Face Harvest for Face Transplantation
Institution where the work was prepared: Duke University Medical Center, Durham, NC, USA
Alessio Baccarani, MD; Keith E. Follmar; Jeffrey R. Marcus; Detlev Erdmann; L. Scott Levin; Duke University
Background:
Total face transplantation has begun to emerge as a reconstructive option in the treatment of patients with massive facial disfigurement. The challenges associated
with immunosuppression and the ethical issues surrounding face transplantation are substantial. One of the most significant technical questions that
remains to be answered before the first total face transplant can be performed is how a facial allograft would be harvested and what tissues it would include.
We present two novel face harvesting techniques based on our understanding of the vascular anatomy.
Methods:
The first technique harvests the skin and soft tissue of the face by dissecting in a subgaleal, sub-SMAS, subplatysmal plane. The second technique harvests the
entire soft tissue and bony structure of the face by dissecting in a subperiosteal plane and harvesting the bones of the midface by performing a Le Fort III
osteotomy. These techniques were performed on fresh human cadavers that had been perfused with latex.
Results:
Each face was harvested successfully as a bipedicled flap based on the external carotid arteries, the external jugular veins, and the facial veins. The sub-SMAS
flap appeared to be well perfused by the external carotid system throughout. The subperiosteal Le Fort III flap appeared to be well perfused everywhere except
for portions of the zygomatic arch and the sphenoid bone.
Conclusions:
Each of these two techniques is a theoretically viable approach to face harvesting for face transplantation and they address different reconstructive needs.
Substantial challenges remain before face transplantation can become a viable reconstructive option.
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