COMPOSITE TISSUE ALLOTRANSPLANTATION

COMPOSITE  TISSUE  ALLOTRANSPLANTATION  

       

      

        After the report of the first microvascular tissue transfer  the free transfer of autologous tissue became the  mainstay for  treatment  of complex soft tissue defects and with reimplantation  of the  hand and digits, the modern era of replantation in reconstructive  surgery began in the  1960.

    

        Composite tissue allotransplantation (CTA)  is a term that includes transplantation of multiple tissues of ecodermal and mesodermal  origin. It  involves simultaneous transplantation  of tissue  components  involving  skin, muscle, nerve bone and tendons. Transplantation of hand is one of the best examples of CTA concept and it has  brought the  attention  of the  scientific  community and the public  to this new field of transplantation. The growth of solid organ transplantation also parallels the emergence of newer immunosuppressive drugs.

       The first hand transplant was performed in Lyon France in 1998, with eventual graft loss due to noncompliance with immunosuppression. The clinicopathological  freatures of rejection were largely confined to skin with milder involvement of muscle   and tendon and sparing of bone and joints.

     Louisville School of Medicine  in United  States has taken lead  in hand transplant surgery in the United  States. Of the approximately 30 hand transplants done worldwide, 3 have been done in Louisville. A hand  transplant protocol by the University  was drawn up. Patient recruitment  is rigid. The transplant protocol by the University  was drawn up. Patient  recruitment  is rigid. the pretransplant  psychiatric evaluation  screening tests are similar to solid organ transplantation  and include routine  blood work out. ABO  type, cancel reactive antibody, infection screen , chest X-ray, cardiac evaluation, etc .

      Decreased donor has to meet the standard criteria for determination of brain death. Donation after cardiac death is not  considered. All donors were from the jurisdiction of the  local organ procurement organization. ABO blood group compatibility and a negative  crossmatch with the recipient was necessary. Absolute contraindications included active  intravenous drug use. A detailed evaluation of the limbs of the potential donors included range of motion in all joints and absence of arthritis.

     The details  of the donor procedure is described briefly. A circumferential incision is made around the  distal arm with identification of underlying  veins and cutaneous  nerves. another longitudinal incision is made along  the medical side of the arm over the brachial vessels  to enable cannulation for cold perfusion of the limb with the University of Wisconsin  solution.

        The sequency of tissue repair proceeds in the following order: bony fixation, arterial revascularization, vein repair, tendon repair and nerve  repair. All  patients  received  heparin for 48 hours postoperatively.

       Immunosuppression   was induced with basiliximab , tacrolims, MMF  and steroids, The digits were fixed in metacarpophalangeal  fiexion.  The   wrist was in a dynamic brace. a transcutaneous electrical  nerve stimulation unit to decrease pain and  electric muscle stimulator were  used throughout the rehabilitation course. Skin biopsies were performed to monitor rejection.

       In  Malaysis, an upper extremity transplantation was performed at the level of the shoulder on a 28 day old neonate  born with congential absence of one arm.  The identical  twin had fatal brain anomaly and was the donor of  the limb. The  transplanted limb grew at the same rate as the native limb and after 7 years was  functional. One major controversy surrounding CTA is the  toxicity of immunosuppression with an increased risk of cancer, organ failure and opportunistic infections.

      Many other tissues have been successfully transplanted to restore tissue loss from trauma or tumor. Simultaneous and sequential abdominal wall transplantation  coincident with intestinal transplantation has been reported from University of Miami. A 40- year- old man received the  first  successful human laryngeal transplant in 1998. A human leukocyte antigen matched  laryngopharyngeal complex including  thyroid,prathyroids and five rings of trachea were transplanted  along with   anastomosis of both superior and one of the recurrent laryngeal nerves.

       At a follow- up of more than 7 years, the patient had excellent  function, normal swallowing and good phonation. Other workers have reported 13 laryngeal transplantations with 90 percent graft survival at 2 years using immunosuppression similar to renal transplantation . Patients with  severe disfigurement of face not amenable to reconstruction are likely to benefit from partial face transplantation. The first  facial transplant was in a 38- year- old woman, disfigured by a severe dog bite who received a  central and lower  facial transplant in 2005.  A sentinel skin graft was placed in the left inframammary area to monitor rejection.  Sensitivity to  light touch and temperature returned by 6 months , whereas  motor recovery allowing complete mouth closure was achieved at 10 months . Despite two episodes of acute rejection and renal  dysfunction requiring cessation of tacrolimus, the patient is satisfied with aesthetic result and  is maintained on sirolimus, MMF and prednisone.