Graft weight/recipient body weight ratio (G/R ratio) in living-related liver transplantation for pediatric patients: abdominal wall closure in cases with a large G/R ratio

Large-for-Size Orthotopic Liver Transplantation: a Systematic Review of Definitions, Outcomes, and Solutions

BACKGROUND

We systematically reviewed the literature on definitions and outcomes of large-for-size (LFS) syndrome in orthotopic liver transplantation (LT).

METHODS

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Cochrane Library, PubMed, and Embase were searched (January 1990-January 2019) for studies reporting LFS in LT. Primary outcomes were definitions and mortality of LFS LT.

RESULTS

Eleven studies reporting patients with LFS LT were identified. Four different formulas (graft-to-recipient weight ratio (GRWR), body surface area index (BSAi), donor standardized total liver volume (sTLV)-to-recipient sTLV ratio, and graft weight/right anteroposterior distance (RAP) ratio) with their critical thresholds were found. There were 81 patients (54% women) with a median weight and height of 62.5 kg (range, 40-105 kg) and 165 cm (range, 145-180 cm). The median graft weight was 1772 g (range, 1290-2400 g), and the median GWRW was 2.77% (range, 2.1-4.00%). Graft venous outflow obstruction was described in seven patients (8.6%). At the time of LT, fascial closure was not achieved in 24 patients (29.6%) and the graft size was reduced by a liver resection in three patients (3.7%). Thirteen deaths (16%) were reported in the first 90 postoperative days with two patients undergoing re-transplant.

CONCLUSIONS

LFS LT remains heterogeneously defined but characterized by high mortality rates despite the use of tailored surgical solutions (graft reduction and open abdomen). A composite definition is proposed in order to better describe LFS clinical syndrome.

Liver and vascularized posterior rectus sheath fascia composite tissue allotransplantation

Abdominal wall closure in pediatric solid organ recipients may be confounded by donor size discrepancy and structural insults from previous surgery. Here we describe the novel use of vascularized donor abdominal wall posterior rectus sheath fascia, as a composite tissue allotransplant (CTA), to achieve abdominal wall closure in a liver and double kidney pediatric recipient who could not be closed primarily due to donor/recipient size mismatch. The posterior rectus sheath fascia was procured in continuity with the liver and falciform ligament. Blood supply was achieved using the single hepatic artery anastomosis as part of the standard liver transplantation procedure. Specimens of posterior rectus sheath fascia taken on postoperative days 3 and 30 showed no signs of acute rejection. The patient succumbed to an overwhelming fungal infection on day 51, with no signs of intraabdominal involvement. The patient received no additional immunosuppression in conjunction with the posterior rectus sheath fascia allotransplant.

Incidence and management of abdominal closure-related complications in adult intestinal transplantation

BACKGROUND

We sought to determine the best strategy to overcome difficult abdominal wall closures in intestinal transplantation (ITx).

METHODS

Among 38 adult recipients of 39 ITxs from deceased donors, the median number of previous laparotomies was 2.0 per patient, with a median donor-to-recipient body weight ratio of 1.1. Eight patients (21%) had full residual intestinal length before transplant. Abdominal wall closure after transplant was considered difficult in 15 (39.5%) patients (group A). To overcome size mismatching, we performed two graft reductions, five skin-only closures, one two-step abdominal wall closure, four prosthetic mesh closures, and three abdominal wall transplants. In the remaining 23 (60.5%) patients, a regular abdominal closure was performed (group B).

RESULTS

Twelve patients (32%) experienced complications related to abdominal wall closure, 10 (67%) in group A and 2 (8.7%) in group B (P<0.0001). Abdominal closure-related mortality was 6.7% (1/15) and 4.3% (1/23), respectively (P=1.0). In group A, there were six incisional hernias (one of them after abdominal wall transplant), although all four patients with mesh experienced mesh infection. Two of them developed intestinal fistulae, leading to patient death in one case. In group B, one patient with unfavorable donor/recipient size matching had fatal vascular thrombosis of a multivisceral graft caused by compression after abdominal closure.

CONCLUSIONS

A careful evaluation of abdominal cavity is necessary in candidates for ITx. In our experience, closure with mesh should be avoided because of the high rate of complications. Abdominal wall transplantation is a feasible option when a difficult abdominal wall closure is expected.

Incidence and management of abdominal wall defects after intestinal and multivisceral transplantation

BACKGROUND

Successful primary closure of the abdominal wall following visceral organ transplantation is not always feasible. Primary closure under tension can lead to fascial ischemia or necrosis, with subsequent dehiscence. Thus, alternate techniques to achieve abdominal wall closure are an important technical aspect in intestinal transplantation. The authors review their experience managing abdominal wall defects following intestinal or multivisceral transplantation.

METHODS

A retrospective review of the transplant database revealed 28 intestinal transplants in 24 patients from program inception in 1991 to January of 2002. The management of six intestinal transplant recipients with giant posttransplant abdominal wall defects is reviewed, and a novel technique is described for initially managing defects with prosthetic grafts that were serially reduced in size until a clean granulating bed was established, at which time they underwent permanent coverage using a meshed split-thickness skin graft.

RESULTS

Of the 28 transplants, primary fascial closure was possible in only 14. In the other 14 patients, the fascia could not be closed primarily at the time of transplantation. The donor weight-to-recipient weight ratio was significantly greater in patients with abdominal wall closure problems (0.64 versus 1.09; p < 0.005). The incidence of retransplantation was also higher in those with abdominal closure problems compared with those whose fascia could be closed primarily (five of 14 versus one of 14). The six patients managed with skin graft closure did not have any wound complications after grafting.

CONCLUSIONS

Abdominal wall defect after intestinal and multivisceral transplantation is a common problem without an ideal solution. Use of a skin graft on granulating abdominal viscera frozen with adhesions is a simple and reasonable solution to a complex problem.

Temporary silastic mesh closure for adult liver transplantation: a safe alternative for the difficult abdomen

Primary fascial closure is often difficult after adult orthotopic liver transplantation (OLT), complicated by donor-to-recipient graft size mismatch, post-reperfusion hepatic edema, coagulopathy, or intestinal edema. Attempts at closing the abdomen under these circumstances can cause increase in intra-abdominal pressures, resulting in significant complications, including graft loss. Temporary closure with silastic mesh has been used as a viable option in children receiving transplants, but there is no experience recorded with its use in adults. A retrospective review was conducted on 200 consecutive liver transplantations performed over 42 months (October 2002 to February 2006). Records were evaluated for patient and donor demographics, perioperative factors including Model for End-Stage Liver Disease and Child-Turcotte-Pugh scores, indications for OLT, ischemic times, blood product administration, and use of temporary silastic mesh closure. Patients requiring silastic mesh were further evaluated for indication, time to primary fascial closure, duration of intubation, length of stay, graft function, and complications (infectious, vascular, biliary, and hernia development). Comparisons were made with a cohort of patients undergoing OLT over the same time period but who were closed primarily, without the use of temporary silastic mesh. Fifty-one liver transplantations (25.5%) of the 200 total transplant cohort used silastic mesh closure. Comparison of the cohorts (primary closure vs. temporary mesh) revealed that no differences existed, except the requirement of all blood products was significantly greater in the silastic mesh group (P < 0.001). Bowel edema (47.1%) and coagulopathy (37.3%) were the most common indications for mesh closure, with less frequent reasons including donor to recipient size mismatch (11.8%), hemodynamic instability, and a large preexisting fascial defect (2.0% each). The average time from transplant to final fascial closure was 3.4 days (range 2-9 days). In the silastic cohort, 41 transplants where closed primarily, 3 required the addition of synthetic mesh, and 6 had component separation and flap closure. After fascial closure, the mean time to extubation was 1 day. The median length of follow-up was 1.3 years for the silastic closure group. Long-term wound complications in the silastic closure group included 1 instance of colonic fistula, 2 incisional hernias, and 2 wound infections. The 30-day and 1-year patient survival for this group were 93.6 and 82.4%, respectively, and the graft survival for those same periods were 90.2 and 77.7%, respectively. Wound complications, rates of hepatic artery thrombosis or stricture, portal vein thrombosis or stricture, biliary complications, and allograft and patient survival were no different than those in patients undergoing initial primary closure. In adult liver transplantation with a difficult (or potentially difficult) abdomen, temporary closure with silastic mesh was found to allow for uncomplicated fascial closure in a short period of time, with rapid extubation times, excellent graft function, and minimal instances of infectious or wound complications. In circumstances where large amounts of blood products are required, where a size mismatch exists, or where bowel edema is present during adult liver transplantation, temporary closure with silastic mesh is an ideal strategy.

Estimation of liver size for liver transplantation: the impact of age and gender

In general, the liver is considered to be larger in males than in females. In the present study, data on liver weight from 728 legal autopsies were analyzed with respect to gender, age, body height (BH), body weight (BW), body mass index (BMI), and body surface area (BSA). Descriptive statistics revealed that liver weight increases with age, reaching maximum values between 41 and 50 years in men and between 51 and 60 years in women. Thereafter, liver weight decreases again. Because this loss in liver weight starts earlier in men while liver weight continues to rise in women, the difference in liver weight between men and women is lost above the age of 50. Thus, this age defines a threshold value below which gender is expected to be a critical factor in the calculation of liver weight. When demographic data mentioned above were subjected to multiple stepwise linear regression analysis, liver weight (LW) was best predicted in younger people (16-50 years) by body weight, age, and gender: LW (g) = 452 + 16.34 x BW + 11.85 x age - 166 x gender (r(2) = 0.381; "gender": 1 = female, 0 = male). In contrast, in elderly people (51-70 years) LW was best predicted by BW and age only. Gender was not a significant factor. LW (g) = 1390 + 15.94 x BW - 12.86 x age (r(2) = 0.35). When these formulas were applied to demographic data from 97 organ donors and compared to published formulas (which, however, do not consider the age-dependent effects of gender), the new formulas best predicted male to female liver weight ratios in younger and elderly donors. In conclusion, the new formulas might better predict liver weight in organ donors and transplant recipients to avoid liver size mismatch.

Adult living donor liver transplantation: current status

Living donor liver transplantation was developed in response to a shortage of full-size grafts for children. The progression from reduced-size cadaveric grafts to use of living donors occurred subsequent to expansion of liver anatomy knowledge and practical use of hepatic segments. A major benefit of pediatric live donor liver transplantation is the grafting of children without using livers from the cadaver donor pool. A major drawback of the procedure relates to the need to perform surgery and assign risk to an otherwise healthy individual. The ethical challenge has been discussed in detail and, although not ideal, the procedure "passes muster" on grounds of informed consent and the good of helping another human being. Formidable success appears to have been attained with the adult-to-adult procedure thus far; however, the transplant community still awaits center-specific and compiled data to determine whether the procedure truly reduces adult waiting list times for liver transplant recipients with minimal donor risk.