Indirect markers for length adjustment in distal biceps tendon allograft reconstruction

Chronic musculotendinous retraction, shortening and fibrosis after distal biceps tendon tears makes a primary reconstruction often difficult or even impossible. Interposition reconstruction with allograft provides a solution, however there is no consensus about appropriate intraoperative graft length adjustment. Therefore, the purpose of this study was to find a practical reference value for distal biceps tendon length adjustment. Three-dimensional surface models of healthy distal biceps tendons were created based on 85 MRI scans. The tendon length was measured from the myotendinous junction to the insertion on the bicipital tuberosity. Inter-epicondylar distance (IED) and radial head diameter (RHD) were measured on antero-posterior radiographs as a surrogate for patient size. Correlations between the tendon length and IED, RHD and patient’s height (PH) were calculated. Mean length of the external part of the distal biceps tendon was 69mm (female 64mm, male 71mm). The tendon length in mm was on average 1.1 times of the IED (mm), 3 times of the RHD (mm) and 0.4 times of PH (cm). Herewith, the tendon length could be predicted within a narrow range of +/-1cm in 84% by using IED, 82% by using RHD and 80% by using PH. Intra- and inter-reader reliabililty of IED and RHD was excellent (R² = 0.938–0.981). The distal biceps tendon length can be best predicted within 1cm with an accuracy of 82–84% using the IED and RHD with an excellent intra- and inter-reader reliability.

Impact of small-for-size liver grafts on medium-term and long-term graft survival in living donor liver transplantation: A meta-analysis

BACKGROUND

Small-for-size grafts (SFSGs) in living donor liver transplantation (LDLT) could optimize donor postoperative outcomes and also expand the potential donor pool. Evidence on whether SFSGs would affect medium-term and long-term recipient graft survival is lacking.

AIM

To evaluate the impact of small-for-size liver grafts on medium-term and long-term graft survival in adult to adult LDLT.

METHODS

A systematic review and meta-analysis were performed by searching eligible studies published before January 24, 2019 on PubMed, EMBASE, and Web of Science databases. The primary outcomes were 3-year and 5-year graft survival. Incidence of small-for-size syndrome and short term mortality were also extracted.

RESULTS

This meta-analysis is reported according to the guidelines of the PRISMA 2009 Statement. Seven retrospective observational studies with a total of 1821 LDLT recipients were included in the meta-analysis. SFSG is associated with significantly poorer medium-term graft survival. The pooled odds ratio for 3-year graft survival was 1.58 [95% confidence interval 1.10-2.29, P = 0.014]. On the other hand, pooled results of the studies showed that SFSG had no significant discriminatory effect on 5-year graft survival with an odds ratio of 1.31 (95% confidence interval 0.87-1.97, P = 0.199). Furthermore, incidence of small-for-size syndrome detected in recipients of SFSG ranged from 0-11.4% in the included studies.

CONCLUSION

SFSG is associated with inferior medium-term but not long-term graft survival. Comparable long-term graft survival based on liver graft size shows that smaller grafts could be accepted for LDLT with appropriate flow modulatory measures. Close follow-up for graft function is warranted within 3 years after liver transplantation.

Hamstring Autograft Too Small: How Much Allograft Do You Need to Supplement to a Desired Hybrid Graft Size?

PURPOSE

To determine a simple rule for choosing supplemental allograft size for hybrid anterior cruciate ligament reconstruction using mathematical and cadaveric models.

METHODS

Mathematical and cadaveric models were used to determine the rule. The mathematical model required application of the geometric Pythagorean theorem to add areas of circles. Cadaveric semitendinosus and gracilis tendons were combined in multiple quadrupled hamstring size combinations and then sized using standard surgical techniques to confirm the mathematical model.

RESULTS

Geometric measurement, not simple addition, of graft diameters was required to determine the final graft size. Direct comparison of cadaveric and mathematical models showed close relations. If a final graft size of 7 mm is desired, an added diameter of all grafts of approximately 9.5 mm is needed. If a final graft size of 8 mm is desired, an added diameter of all grafts of approximately 11 mm is needed. If a final graft size of 9 mm is desired, an added diameter of all grafts of approximately 12.5 mm is needed. If a final graft size of 10 mm is desired, an added graft diameter of approximately 14 mm is needed. Cadaveric hamstring measurements were similar to the mathematical model.

CONCLUSIONS

By use of mathematical and cadaveric models, simple rules for determining the additional size of allograft diameter needed to supplement undersized hamstring autograft were created.

CLINICAL RELEVANCE

With the increasing availability of allograft types and sizes, surgeons currently have no guidelines on the size of allograft that is required to supplement an undersized hamstring autograft. Simple rules were created for determining the amount of allograft supplementation required for undersized hamstrings and are easily applied to clinical situations.

Split liver transplantation: Current developments

In 1988, Rudolf Pichlmayr pioneered split liver transplantation (SLT), enabling the transplantation of one donor liver into two recipients - one pediatric and one adult patient. In the same year, Henri Bismuth and colleagues performed the first full right/full left split procedure with two adult recipients. Both splitting techniques were rapidly adopted within the transplant community. However, a SLT is technically demanding, may cause increased perioperative complications, and may potentially transform an excellent deceased donor organ into two marginal quality grafts. Thus, crucial evaluation of donor organs suitable for splitting and careful screening of potential SLT recipients is warranted. Furthermore, the logistic background of the splitting procedure as well as the organ allocation policy must be adapted to further increase the number and the safety of SLT. Under defined circumstances, in selected patients and at experienced transplant centers, SLT outcomes can be similar to those obtained in full organ LT. Thus, SLT is an important tool to reduce the donor organ shortage and waitlist mortality, especially for pediatric patients and small adults. The present review gives an overview of technical aspects, current developments, and clinical outcomes of SLT.

Feasibility of using marginal liver grafts in living donor liver transplantation

Liver transplantation (LT) is one of the most effective treatments for end-stage liver disease caused by related risk factors when liver resection is contraindicated. Additionally, despite the decrease in the prevalence of hepatitis B virus (HBV) over the past two decades, the absolute number of HBsAg-positive people has increased, leading to an increase in HBV-related liver cirrhosis and hepatocellular carcinoma. Consequently, a large demand exists for LT. While the wait time for patients on the donor list is, to some degree, shorter due to the development of living donor liver transplantation (LDLT), there is still a shortage of liver grafts. Furthermore, recipients often suffer from emergent conditions, such as liver dysfunction or even hepatic encephalopathy, which can lead to a limited choice in grafts. To expand the pool of available liver grafts, one option is the use of organs that were previously considered “unusable” by many, which are often labeled “marginal” organs. Many previous studies have reported on the possibilities of using marginal grafts in orthotopic LT; however, there is still a lack of discussion on this topic, especially regarding the feasibility of using marginal grafts in LDLT. Therefore, the present review aimed to summarize the feasibility of using marginal liver grafts for LDLT and discuss the possibility of expanding the application of these grafts.

A new index predicts early allograft dysfunction following living donor liver transplantation: A propensity score analysis

OBJECTIVE/AIM

The aim of this study was to identify a new index to predict early allograft dysfunction following living donor liver transplantation.

METHODS

The study enrolled 260 adult living donor liver transplantation recipients. Postoperative laboratory variables were assessed for their association with the prevalence of early allograft dysfunction using the inverse probability of treatment weighting and propensity-score matching (n=93 pairs) analysis.

RESULTS

Forty-seven recipients (18.1%) developed early allograft dysfunction. In multivariable analysis, the alanine aminotransferase and gamma-glutamyl transpeptidase levels on postoperative day 1 were independent predictors of early allograft dysfunction. The alanine aminotransferase to gamma-glutamyl transpeptidase ratio (AGR) was developed. All cases were divided into two groups (Group 1 [AGR≥8.47, n=103] and Group 2 [AGR<8.47, n=157]). AGR≥8.47 (OR 10.345, 95%CI 4.502-23.772, p<0.001), hepatorenal syndrome (OR 3.016, 95%CI 1.119-8.125, p=0.029), and graft to recipient weight ratio <0.8% (OR 2.155, 95%CI 1.004-4.624, p=0.049) were independent risk factors for early allograft dysfunction. The prevalence of early allograft dysfunction was higher in group 1 (after adjusting for inverse probability of treatment weighting [n=39; 37.9% vs n=8; 5.1%] and propensity-score matching [n=33; 35.5% vs n=2; 2.2%]) than that in group 2 (p<0.001).

CONCLUSIONS

The postoperative AGR is a practical index for predicting early allograft dysfunction after living donor liver transplantation.