Split/Reduced Liver Transplantation “IMSS”: The First Two Cases and Literature Overview

Alternative methods are required to permit an increase in the number of grafts, Split/liver transplantation (SLT), it is considered one of them, and it is defi ned as the division of a deceased donor’s liver into two different parts functionally independent, and the transplantation of each of them into a different recipient [1-3]. Transplantation of partial-liver allograft for children was advocate by Smith in 1969 and was initially performed through the surgical reduction of a larger child or adult cadaver allograft, termed reduced liver transplantation by Bismuth, Houssin and Broelsh et al. in 1984 [1,3]. The term SLT was simultaneously reported by Pichlmayr et al. and Bismuth et al. in 1989. Their technique involved the ex vivo division of an adult cadaver liver into a pediatric allograft and a remnant adult allograft [1-4]. These efforts were an attempt to satisfy an increasing demand for pediatric cadaver allografts that had resulted in prolonged waiting periods and a wait-list mortality of approximately 50% at major pediatric referral centers [1-3].


Introduction
Alternative methods are required to permit an increase in the number of grafts, Split/liver transplantation (SLT), it is considered one of them, and it is defi ned as the division of a deceased donor's liver into two different parts functionally independent, and the transplantation of each of them into a different recipient [1][2][3]. Transplantation of partial-liver allograft for children was advocate by Smith in 1969 and was initially performed through the surgical reduction of a larger child or adult cadaver allograft, termed reduced liver transplantation by Bismuth, Houssin and Broelsh et al. in 1984 [1,3]. The term SLT was simultaneously reported by Pichlmayr et al. and Bismuth et al. in 1989. Their technique involved the ex vivo division of an adult cadaver liver into a pediatric allograft and a remnant adult allograft [1][2][3][4]. These efforts were an attempt to satisfy an increasing demand for pediatric cadaver allografts that had resulted in prolonged waiting periods and a wait-list mortality of approximately 50% at major pediatric referral centers [1][2][3].
This technique was performed in selected centers in Europe and the United States to decrease the pediatric waiting Abstract Introduction: The term Split/Liver Transplantation involved the ex vivo division of an adult cadaver liver into a pediatric allograft and a remnant adult allograft. The efforts were an attempt to satisfy an increasing demand for pediatric cadaver allografts that had resulted in prolonged waiting periods and a wait-list mortality of approximately 50% at major pediatric referral centers. The main of this work is given to know our experience in two different cases and encouraged at the adult surgeons to confi de and accept the right allograft of this technique for an adult patient.

Cases:
We performed two reduced procedures by the split liver technique. The fi rst case was a procurement of a male donor of 33 years' old with diagnosis of cerebral death due to aneurysm rupture, and the recipient was a fi ve years' old girl with the diagnosis of biliary atresia. For the second case, we had a male donor of 8 years' old with diagnosis of cerebral death secondary to arteriovenous malformation and the recipient was a 2.9 year´s old girl, with biliary atresia.

Conclusion:
There are no differences in complications between split in cadaveric donor to living liver donor. However for a good outcome, it is important to have a good donor like it is for a good recipient. In our center, the split liver transplantation is uncommon and there is a clear need for better training of surgeons and for improved sharing of information about this needed procedure. mortality, and at the same time to avoid discarding the right side of the liver [1][2][3]5]. Since, there has been a general agreement on anatomic classifi cation made by Couinaud and accept across Asian, European and North American Transplant communities [6,7]. In our center, with the increasing pediatric and adult waiting list, a clinical group and surgeons of IMSS

Cases
September to November 2017 in IMSS, we performed two reduced procedures by the split technique. For the fi rst case, we performed a procurement of a male donor of 33 years' old with body weight 109-kg and the diagnosis of cerebral death due to an aneurysm rupture. Others characteristics as donor are fi nding in table 1 and the recipient was a fi ve years' old girl with the diagnosis of biliary atresia with Kasai procedure. For The second case, in the same hospital (CMNSXXI/Pediatric Hospital Dr Silvestre Frenk F), we had a male donor of 8 years' old, weight 27 kg with the diagnosis of cerebral death secondary to arteriovenous malformation and the recipient was a 2.9 year´s old girl, weight 9.6-kg with diagnosis of biliary atresia with Kasai procedure. She had respiratory distress due to ascites, hypersplenism and hepatomegaly. This recipient was classifi ed like child C.

Technical considerations
The bipartition technique requires only standard surgical facilities with no specialized equipment and have performed concomitant with additional abdominal and thoracic organ procurements [2,4]. Casually in our fi rst donor for splitting, the procurement was multy-organic.

Types of split
Infants have the highest wait-list mortality of all liver transplantation candidates [5,6]. Deceased donor split-liver transplantation, a technique that provides both an adult and pediatric graft, might be the best way to decrease this disproportionate mortality [4,6]. Yet concern for an increased risk to adult split recipients has discouraged its widespread adoption [6,8,9]. We aimed to determine the current risk of graft failure recipients after split-liver transplantation. Adult/ child vs adult/adult: the term split SL includes 2 different entities. The fi rst is the adult /child (ACSL) that generates 2 differently sized grafts: 1 graft including the Couinaud segments II and III, suitable for transplantation into a small child generally not exceeding 30 kg in weight, and the other graft includes segments I and IV to VIII, suitable for an adult transplant [2,4,6,7]. In our cases, the split procedures were planning for children and adults. Ex situ vs IS (in situ); as mentioned above, both in ACSL and in AASL, the division of the liver may be performed IS while the heart is still beating and before fl ushing all the organs [1][2][3]6].
The main advantages of the IS technique are that ischemia time is shorter and that optimal control of bleeding from the cut surface of both grafts may be performed during the splitting procedure itself, so that minimal bleeding is expected after implantation in the recipient [ 1,[3][4][5]11]. On the other hand, the IS technique signifi cantly increases the operation time on the donor, thus impacting the organization of the procedure both for the donor hospital and for the teams involved in procuring other organs [1,3,4]. In our cases, we reduced the liver using the technique of the SLT adult/child with back table to separate the liver (ex-situ) and we organized how to perform this procedure of in situ to minimize bleeding after recipient implantation.

Logistical consideration
Donor and recipient selection are the most important for the successful use of partial grafts, the main reason that we presented this work with 2 different receptors [4,11,12].
However, a good donor selection criterion include ABO compatibility, age, liver function, sizemacth, absent/ scant arrest period, vasopressor requirements, serum sodium concentration and brief donor hospitalization [11][12][13]. Split liver transplantation entails greater requirements in term of time, material and human resources than conventional whole organ liver transplantation and, unavoidably, a learning curve.
Favorable liver graft allocation policies and collaborative coordination among centers represent the basis for a rational, extensive use of this donor source [5,12,13]. In our donors we

Preoperative evaluation
SLT may not be performed safely with all donors. Essential in the success of SLT is the proper selection of a cadaveric liver graft to split. Tissue injury may arise not only from the stress of cold ischemia and perfusion but from manipulation during dissection as well as parenchyma transection [4,5,12].
The young hemodynamically stable potential organ donor with acceptable vasopressor support and a short hospital stay (in intensive care unit= ICU) seems to be most suitable for a split procedure. Indeed, poor donor selection has been recognized as a cause of unfavorable outcomes [3,4,13,14]. Marginal donors are not suitable for splitting [1,3]. An emerging donor source for SLT are recipients with familial amyloid polyneuropathy (FAP) whose liver explants may be used in another recipient in what is referred to as "domino liver transplantation", this procedure has been performed since 1995, domino SLT (splitting an FAP live donor liver for two recipients) has been reported from France and two cases have been performed in Japan to date [3,14].
Appropriate donor and recipient selection are critical to the success of SLT; typically, donor selection is restricted to optimal candidates with respect: age is intended to be kept < 50 years for graft splitting because the liver's regeneration capacity is compromised by aging [1,2,4,9,11]. ABO

Recipient Selection
Split liver recipient selection is even more relevant that good

Split liver procedure
After the procurement the split liver is lengthened by 90 to 120 minutes. The ideal and most important sharing pattern was originally described by Bismuth et al. in 1989; the principal concept of this sharing pattern is its avoidance of multiples branches that would need to be reconstructed in recipient [2,6].  [ 2,6,7,11 ]. This classifi cation and the one refi ned by Bismuth and used as references for partialorgan allografts, in our two patients in this study we performed the same classifi cation. This generates a graft for a small child and an adult or bigger child, respectively or bigger child respectively. And in the split for two adults, this would entail transection of the liver near the main lobar fi ssure to generate two hemi liver grafts [3,5,7,11].
The increased use of split-liver transplant from deceased donors for pediatric recipients hassled to the selection of some recipients weighing more than 30-kg for whom the left lateral lobe (segments II and III) was usually considered too small [9][10][11]. The left lobe frequently has single branch of the portal vein, hepatic duct and venous outfl ow that is a common channel of the left and middle hepatic veins ( Figure 5). The right lobe often has a single right hepatic artery, but multiples branches are commonly seen in the venous drainage, hepatic duct and portal vein. The left-sided graft, the right-sided graft retains the remaining main branches, including the common hepatic duct, main portal vein and vena cava [6,11,18]. Split liver transplantation for two adults is technically feasible [13,16,17,19].

Split liver graft implantation
The technique was selected as indicated for each split graft-patient couple with percutaneous Veno-venous bypass installed as needed. The implantation was adapted as necessary using preservation of the native vena cava, arterial or venous grafts, or the prevention of kinking of the venous anastomosis.
The left graft is rotated through 180° of sagittal orientation so that the hilar structures are brought into an anterior and medial location coaxial with the native liver pedicle [8,[13][14][15].

Postoperative care
The usual post-transplant care for the center depends of every liver transplantation center. Even though, the recipient could receive in UCI. In our case graft perfusion was checked by Doppler ultrasound examination daily in the intensive care unit (UCI). Patients whose partial thromboplastin time was less than 1.3 times control or whose platelet count was more than 30,000/ were anticoagulated with heparin [8,13,14].  [13,16,21]. In this work: we had a good outcome with the recipient of child B in the fi rst three months of transplant, the recipient child C had a good donor, in fact by its hemodynamic instability she presented a grade V of the Clavien-Dindo classifi cation due to disseminate intravascularcoagulation ( Figure 5).

Complication in split liver
However, in our center it is an obligation to perform this  pre-transplantation mortality. Since, we observed in both cases in this work that the end result is also highly dependent on the optimal choice of donor and recipients. In our center, the split liver transplantation is uncommon and there is a clear need for better training of surgeons and for improved sharing of information about this needed procedure.