• Title/Summary/Keyword: Vascularized composite allografts

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Clinical and preclinical tolerance protocols for vascularized composite allograft transplantation

  • Yang, Jerry Huanda;Johnson, Ariel C.;Colakoglu, Salih;Huang, Christene A.;Mathes, David Woodbridge
    • Archives of Plastic Surgery
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    • v.48 no.6
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    • pp.703-713
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    • 2021
  • The field of vascularized composite allografts (VCAs) has undergone significant advancement in recent decades, and VCAs are increasingly common and accepted in the clinical setting, bringing hope of functional recovery to patients with debilitating injuries. A major obstacle facing the widespread application of VCAs is the side effect profile associated with the current immunosuppressive regimen, which can cause a wide array of complications such as infection, malignancy, and even death. Significant concerns remain regarding whether the treatment outweighs the risk. The potential solution to this dilemma would be achieving VCA tolerance, which would allow recipients to receive allografts without significant immunosuppression and its sequelae. Promising tolerance protocols are being studied in kidney transplantation; four major trials have attempted to withdraw immunosuppressive treatment with various successes. The common theme in all four trials is the use of radiation treatment and donor cell transplantation. The knowledge gained from these trials can provide valuable insight into the development of a VCA tolerance protocol. Despite similarities, VCAs present additional barriers compared to kidney allografts regarding tolerance induction. VCA donors are likely to be deceased, which limits the time for significant pre-conditioning. VCA donors are also more likely to be human leukocyte antigen-mismatched, which means that tolerance must be induced across major immunological barriers. This review also explores adjunct therapies studied in large animal models that could be the missing element in establishing a safe and stable tolerance induction method.

Functional Reconstruction of a Combined Tendocutaneous Defect of the Achilles Using a Segmental Rectus Femoris Myofascial Construct: A Viable Alternative

  • DeFazio, Michael Vincent;Han, Kevin Dong;Evans, Karen Kim
    • Archives of Plastic Surgery
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    • v.41 no.3
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    • pp.285-289
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    • 2014
  • The composite anterolateral thigh flap with vascularized fascia lata has emerged as a workhorse at our institution for complex Achilles defects requiring both tendon and soft tissue reconstruction. Safe elevation of this flap, however, is occasionally challenged by absent or inadequate perforators supplying the anterolateral thigh. When discovered intraoperatively, alternative options derived from the same vascular network can be pursued. We present the case of a 74-year-old male who underwent composite Achilles defect reconstruction using a segmental rectus femoris myofascial free flap. Following graduated rehabilitation, postoperatively, the patient resumed full activity and was able to ambulate on his tip-toes. At 1-year follow-up, active total range of motion of the reconstructed ankle exceeded 85% of the unaffected side, and donor site morbidity was negligible. American Orthopaedic Foot and Ankle Society and Short Form-36 scores improved by 78.8% and 28.8%, respectively, compared to preoperative baseline assessments. Based on our findings, we advocate for use of the combined rectus femoris myofascial free flap as a rescue option for reconstructing composite Achilles tendon/posterior leg defects in the setting of inadequate anterolateral thigh perforators. To our knowledge, this is the first report to describe use of this flap for such an indication.

Review of Current Facial Allotransplantation and Future Aspects (안면동종이식의 현황고찰과 전망)

  • Seo, Mi Hyun;Lee, Jung A;Oh, Jin Sil;Kim, Soung Min;Myoung, Hoon;Lee, Jong Ho
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.35 no.5
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    • pp.342-351
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    • 2013
  • Advances in immunosuppressive treatments and microsurgical techniques have rendered composite tissues allotransplantation (CTA), such as heteregeneous or non-organ tissues, possible in humans. CTA has evolved dramatically since the first successful rat hind limb allotransplantation. Numerous clinical applications including face, hand, trachea, larynx, and vascularized joint have been performed. Although composite tissue allografts are still in their infancy, they have opened a new era in the field of transplantation surgery and pathology, so that maxillofacial reconstructive surgeons may occasionally be faced with the challenge of diagnosing skin refection of a composite tissue allograft. Facial allotransplantation (FAT) is a new surgical technique that could be considered as a new paradigm in facial reconstruction. Since the first human FAT had been achieved in 2005, 17 cases have been reported in the world up to date. However, many problems such as life-long immunosuppression, immune rejection, ethical problems and psychological problems are remained, so facial CTA is new reconstructive option with no general acceptance. The authors reviewed the indications, the results of 17 cases and their complications, and additional consideration factors in this article, and intended to raise the awareness of oral and maxillofacial surgeons in this type of facial transplantation.

Hemifacial Transplantation Model in Rats

  • Lim, Jong Woo;Eun, Seok Chan
    • Archives of Craniofacial Surgery
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    • v.15 no.2
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    • pp.89-93
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    • 2014
  • Background: To refine facial transplantation techniques and achieve sound results, it is essential to develop a suitable animal model. Rat is a small animal and has many advantages over other animals that have been used as transplantation models. The purpose of this study was to describe a rat hemifacial transplantation model and to verify its convenience and reproducibility. Methods: Animals used in this study were Lewis rats (recipients) and Lewis-Brown Norway rats (donors). Nine transplantations were performed, requiring 18 animals. The hemifacial flap that included the ipsilateral ear was harvested based on the unilateral common carotid artery and external jugular vein and was transferred as a single unit. Cyclosporine A therapy was initiated 24 hours after transplantation and lasted for 2 weeks. Signs of rejection responses were evaluated daily. Results: The mean transplantation time was 1 hour 20 minutes. The anatomy of common carotid artery and external jugular vein was consistent, and the vessel size was appropriate for anastomosis. Six of nine allografts remained good viable without vascular problems at the conclusion of study (postoperative 2 weeks). Conclusion: The rat hemifacial transplantation model is suitable as a standard transplantation training model.