The liver as a central "hub" of the immune system: pathophysiological implications.

The purpose of this review is to describe the immune function of the liver, guiding the reader from the homeostatic tolerogenic status to the aberrant activation demonstrated in chronic liver disease. An extensive description of the pathways behind the inflammatory modulation of the healthy liver will be provided focusing on the complex immune cell network residing within the liver. The limit of tolerance will be presented in the context of organ transplantation, seizing the limits of homeostatic mechanisms that fail in accepting the graft, progressing eventually toward rejection. The triggers and mechanisms behind chronic activation in metabolic liver conditions and viral hepatitis will be discussed. The last session will be dedicated to one of the greatest paradoxes for a tolerogenic organ, developing autoimmunity. Through the description of the three most common autoimmune liver disease, the autoimmune reaction against hepatocytes and biliary epithelial cells will be dissected.

Robotic and Laparoscopic Adrenalectomy for Pheochromocytoma: An International Multicenter Study.

BACKGROUND AND OBJECTIVE: Robotic adrenalectomy (RA) has attracted interest as an alternative to laparoscopic adrenalectomy (LA) for patients with pheochromocytoma, although its beneficial effects are uncertain. Our aim was to compare RA and LA outcomes for these patients. METHODS: Data for patients who underwent RA or LA for pheochromocytoma in 46 international centers between 2012 and 2022 were reviewed. We analyzed baseline characteristics and postoperative complications at discharge, 90 d, and 1 yr. We conducted propensity score matching (PSM; 1:1 ratio) and multivariable analyses to evaluate outcomes and risk factors for the occurrence of complications and higher Comprehensive Complication Index (CCI). KEY FINDINGS AND LIMITATIONS: Of 1755 patients, 1613 (91.9%) underwent LA and 142 (8.1%) underwent RA. Estimated blood loss, conversion rate, complication rate, and CCI at discharge, 90 d, and 1 yr were similar between the groups. However, RA was associated with a longer operative time in comparison to LA (100 vs 123 min; p < 0.001), but not after PSM (p = 0.120). Multivariable analysis revealed that Charlson comorbidity index (odds ratio [OR] 1.17, 95% confidence interval [CI] 1.07-1.29; p = 0.001), and tumor size per 1-cm increment (OR 1.13, 95% CI 1.07-1.21; p < 0.001) were independently associated with the incidence of complications, but there was no significant difference in complication rates between the LA and RA groups (OR 1.09, 95% CI 0.63-1.87; p = 0.767). After PSM, RA was associated with a lower rate of severe (grade ≥3a) complications in comparison to LA (p = 0.023). CONCLUSIONS AND CLINICAL IMPLICATIONS: RA is a safe alternative to LA and yields similar outcomes for patients with pheochromocytoma. RA may be associated with a lower likelihood of severe complications. Further studies are warranted to determine the role of robotic surgery in pheochromocytoma. PATIENT SUMMARY: Pheochromocytoma is a rare tumor in the adrenal gland and the gold-standard treatment is surgical removal. We assessed patient outcomes after robot-assisted surgery compared with laparoscopic surgery and found that outcomes are similar, but the rate of severe complications may be lower if a surgical robot is used.

Immunosuppression protocols for emerging oncological indications in liver transplantation: A systematic review and pooled analysis.

The evolving field of liver transplant (LT) oncology calls for tailored immunosuppression protocols to minimize the risk of tumor recurrence. We systematically reviewed the available evidence from inception to May 2023 regarding immunosuppression protocols used in patients undergoing LT for cholangiocarcinoma, neuroendocrine tumors (NET), hepatic-endothelial hemangioendothelioma (HEHE) and colorectal liver metastases (CRLM), to identify common practices and to evaluate their association with oncological outcomes. Studies not involving humans, case reports and short case series (i.e., n < 10) were excluded. Among 3,374 screened references, we included 117 studies involving 6,797 patients distributed as follows: cholangiocarcinoma (58.1%), NETs (18.8%), HEHE (7.7%), CRLM (6.8%), mixed neoplasms (6.8%) or others (1.7%). Only 41% of the studies disclosed details of the immunosuppression protocol, and 20.8% of studies provided drug trough concentrations during follow-up. The immunosuppression protocols described were heterogeneous and broadly mirrored routine practices for non-tumoral indications. The only exception was CRLM where tacrolimus minimization -or even withdrawal- in combination with inhibitors of the mammalian target of rapamycin (mTORi) were consistently reported. None of the studies evaluated the relationship between the immunosuppression protocol and oncological outcomes. In conclusion, based on low-quality and indirect scientific evidence, patients with tumoral indications for LT should receive the lowest tacrolimus level tolerated under close surveillance. The combination with mTORi titrated to achieve the top therapeutic range of trough concentrations could allow complete tacrolimus withdrawal. This approach may be particularly useful in patients with cholangiocarcinoma and CRLM, in whom tumor recurrence is the main cause of death. We propose a tool for reporting immunosuppression protocols which could be implemented in future transplant oncology studies.

Incidence, management and outcomes in hepatic artery complications after paediatric liver transplantation: protocol of the retrospective, international, multicentre HEPATIC Registry.

INTRODUCTION: Hepatic artery complications (HACs), such as a thrombosis or stenosis, are serious causes of morbidity and mortality after paediatric liver transplantation (LT). This study will investigate the incidence, current management practices and outcomes in paediatric patients with HAC after LT, including early and late complications. METHODS AND ANALYSIS: The HEPatic Artery stenosis and Thrombosis after liver transplantation In Children (HEPATIC) Registry is an international, retrospective, multicentre, observational study. Any paediatric patient diagnosed with HAC and treated for HAC (at age <18 years) after paediatric LT within a 20-year time period will be included. The primary outcomes are graft and patient survivals. The secondary outcomes are technical success of the intervention, primary and secondary patency after HAC intervention, intraprocedural and postprocedural complications, description of current management practices, and incidence of HAC. ETHICS AND DISSEMINATION: All participating sites will obtain local ethical approval and (waiver of) informed consent following the regulations on the conduct of observational clinical studies. The results will be disseminated through scientific presentations at conferences and through publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: The HEPATIC registry is registered at the ClinicalTrials.gov website; Registry Identifier: NCT05818644.

Evaluating Islet Cell Isolation and Transplantation From Donors Following Medical Assistance in Dying.

Background: Limited information is available regarding outcomes of islet cell isolation (ICI) and transplantation (ITx) using medical assistance in dying (MAiD) donors. We aimed to assess the feasibility and outcomes of ICI and ITx in MAiD donors. Methods: ICI and ITx from MAiD were compared with donation after circulatory death (DCD) type III between 2016 and 2023. Differences of isolated islet equivalents (IEQs), numeric viability and other quantitative in vitro metabolic measures were assessed. Results: Overall, 81 ICIs were available of whom 34 (42%) and 47 (58%) from MAiD and DCD-III, respectively. There were no differences of pancreas and digested tissue weight and islets viability among the 2 groups; however, cold ischemic time was longer in MAiD (11.5 versus 9.1 h; P = 0.021). The IEQ (P < 0.001) and percent trapped (P < 0.001) were higher in the DCD-III; however, MAiD islets demonstrated a higher purity (P = 0.020). Overall, 15 ITx were performed of whom 3 (8.8%) and 12 (25.5%) from MAiD and DCD-III, respectively (P = 0.056). Patients had a median fasting C-peptide of 0.51 ng/mL (interquartile range, 0.30-0.76 nmol/L), with no differences between groups (MAiD = 0.52 versus DCD-III = 0.51; P = 0.718). The median HbA1c was 6.2% (interquartile range, 5.7%-7%) (MAiD = 6.3% versus DCD-III = 6.1%; P = 0.815) and BETA2 scores (MAiD = 7.4 versus DCD-III = 12.8; P = 0.229) did not differ. Conclusions: ICI from MAiD donor pancreas may be successfully transplanted with comparable outcomes to DCD-III and may be used for research. These results justify additional efforts to consider MAiD as another valuable source of grafts for ITx. Further multicenter studies and larger clinical experience are needed to validate our findings.

Incidence of clinically relevant postoperative pancreatic fistula in patients undergoing open and minimally invasive pancreatoduodenectomy: a population-based study.

Purpose: Postoperative pancreatic fistula (POPF) remains a devastating complication of pancreatoduodenectomy (PD). Minimally invasive PD (MIPD), including laparoscopic (LPD) and robotic (RPD) approaches, have comparable POPF rates to open PD (OPD). However, we hypothesize that the likelihood of having a more severe POPF, as defined as clinically relevant POPF (CR-POPF), would be higher in an MIPD relative to OPD. Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) targeted pancreatectomy dataset (2014-2020) was reviewed for any POPF after OPD. Propensity score matching (PSM) compared MIPD to OPD, and then RPD to LPD. Results: Among 3,083 patients who developed a POPF, 2,843 (92.2%) underwent OPD and 240 (7.8%) MIPD; of these, 25.0% were LPD (n = 60) and 75.0% RPD (n = 180). Grade B POPF was observed in 45.4% (n = 1,400), and grade C in 6.0% (n = 185). After PSM, MIPD patients had higher rates of CR-POPF (47.3% OPD vs. 54.4% MIPD, p = 0.037), as well as higher reoperation (9.1% vs. 15.3%, p = 0.006), delayed gastric emptying (29.2% vs. 35.8%, p = 0.041), and readmission rates (28.2% vs. 35.1%, p = 0.032). However, CR-POPF rates were comparable between LPD and RPD (56.8% vs. 49.3%, p = 0.408). Conclusion: The impact of POPF is more clinically pronounced after MIPD than OPD with a more complex postoperative course. The difference appears to be attributed to the minimally invasive environment itself as no difference was noted between LPD and RPD. A clear biological explanation of this clinical observation remains missing. Further studies are warranted.

Small graft size and hepatocellular carcinoma outcomes in living donor liver transplantation: a retrospective multicentric cohort study.

INTRODUCTION: This study examined associations between the graft-to-recipient weight ratio (GRWR) for adult-to-adult living donor liver transplantation (LDLT) and hepatocellular carcinoma (HCC) outcomes. MATERIALS AND METHODS: Data from patients in the Korean Organ Transplantation Registry who underwent LDLT for HCC from 2014 to 2021 were retrospectively reviewed. Patients were categorized using the cutoff GRWR for HCC recurrence determined by an adjusted cubic spline (GRWR <0.7% vs. GRWR ≥0.7%). Recurrence-free survival (RFS) and HCC recurrence were analyzed in the entire and a 1:5 propensity-matched cohort. RESULTS: The eligible cohort consisted of 2005 LDLT recipients [GRWR <0.7 ( n =59) vs. GRWR ≥0.7 ( n =1946)]. In the entire cohort, 5-year RFS was significantly lower in the GRWR <0.7 than in the GRWR ≥0.7 group (66.7% vs. 76.7%, P =0.019), although HCC recurrence was not different between groups (77.1% vs. 80.7%, P =0.234). This trend was similar in the matched cohort ( P =0.014 for RFS and P =0.096 for HCC recurrence). In multivariable analyses, GRWR <0.7 was an independent risk factor for RFS [adjusted hazard ratio (aHR) 1.89, P =0.012], but the result was marginal for HCC recurrence (aHR 1.61, P =0.066). In the pretransplant tumor burden subgroup analysis, GRWR <0.7 was a significant risk factor for both RFS and HCC recurrence only for tumors exceeding the Milan criteria (aHR 3.10, P <0.001 for RFS; aHR 2.92, P =0.003 for HCC recurrence) or with MoRAL scores in the fourth quartile (aHR 3.33, P <0.001 for RFS; aHR 2.61, P =0.019 for HCC recurrence). CONCLUSIONS: A GRWR <0.7 potentially leads to lower RFS and higher HCC recurrence after LDLT when the pretransplant tumor burden is high.

Cost-competitive decentralized ammonia fertilizer production can increase food security.

The current centralized configuration of the ammonia industry makes the production of nitrogen fertilizers susceptible to the volatility of fossil fuel prices and involves complex supply chains with long-distance transport costs. An alternative consists of on-site decentralized ammonia production using small modular technologies, such as electric Haber-Bosch or electrocatalytic reduction. Here we evaluate the cost-competitiveness of producing low-carbon ammonia at the farm scale, from a solar agrivoltaic system, or using electricity from the grid, within a novel global fertilizer industry. Projected costs for decentralized ammonia production are compared with historical market prices from centralized production. We find that the cost-competitiveness of decentralized production relies on transport costs and supply chain disruptions. Taking both factors into account, decentralized production could achieve cost-competitiveness for up to 96% of the global ammonia demand by 2030. These results show the potential of decentralized ammonia technologies in revolutionizing the fertilizer industry, particularly in regions facing food insecurity.

Efficiency of machine perfusion in pediatric liver transplantation.

Liver transplantation is the only life-saving procedure for children with end-stage liver disease. The field is however heterogenic with various graft types, recipient age, weight, and underlying diseases. Despite recently improved overall outcomes and the expanded use of living donors, waiting list mortality remains unacceptable, particularly in small children and infants. Based on the known negative effects of elevated donor age, higher body mass index, and prolonged cold ischemia time, the number of available donors for pediatric recipients is limited. Machine perfusion has regained significant interest in the adult liver transplant population during the last decade. Ten randomized controlled trials are published with an overall advantage of machine perfusion techniques over cold storage regarding postoperative outcomes, including graft survival. The concept of hypothermic oxygenated perfusion (HOPE) was the first and only perfusion technique used for pediatric liver transplantation today. In 2018 the first pediatric candidate received a full-size graft donated after circulatory death with cold storage and HOPE, followed by a few split liver transplants after HOPE with an overall limited case number until today. One series of split procedures during HOPE was recently presented by colleagues from France with excellent results, reduced complications, and better graft survival. Such early experience paves the way for more systematic use of machine perfusion techniques for different graft types for pediatric recipients. Clinical reports of pediatric liver transplants with other perfusion techniques are awaited. Strong collaborative efforts are needed to explore the effect of perfusion techniques in this vulnerable population impacting not only the immediate posttransplant outcome but the development and success of an entire life.

Routine utilization of machine perfusion in liver transplantation: Ready for prime time?

The last decade has been notable for increasing high-quality research and dramatic improvement in outcomes with dynamic liver preservation. Robust evidence from numerous randomized controlled trials has been pooled by meta-analyses, providing the highest available evidence on the protective effect of machine perfusion (MP) over static cold storage in liver transplantation (LT). Based on a protective effect with less complications and improved graft survival, the field has seen a paradigm shift in organ preservation. This editorial focuses on the role of MP in LT and how it could become the new "gold standard". Strong collaborative efforts are needed to explore its effects on long-term outcomes.

Data-driven models and digital twins for sustainable combustion technologies.

We highlight the critical role of data in developing sustainable combustion technologies for industries requiring high-density and localized energy sources. Combustion systems are complex and difficult to predict, and high-fidelity simulations are out of reach for practical systems because of computational cost. Data-driven approaches and artificial intelligence offer promising solutions, enabling renewable synthetic fuels to meet decarbonization goals. We discuss open challenges associated with the availability and fidelity of data, physics-based numerical simulations, and machine learning, focusing on developing digital twins capable of mirroring the behavior of industrial combustion systems and continuously updating based on newly available information.

Recent outcomes of liver transplantation for Budd-Chiari syndrome: A study of the European Liver Transplant Registry (ELTR) and affiliated centers.

BACKGROUND AND AIMS: Management of Budd-Chiari syndrome (BCS) has improved over the last decades. The main aim was to evaluate the contemporary post-liver transplant (post-LT) outcomes in Europe. APPROACH AND RESULTS: Data from all patients who underwent transplantation from 1976 to 2020 was obtained from the European Liver Transplant Registry (ELTR). Patients < 16 years, with secondary BCS or HCC were excluded. Patient survival (PS) and graft survival (GS) before and after 2000 were compared. Multivariate Cox regression analysis identified predictors of PS and GS after 2000. Supplemental data was requested from all ELTR-affiliated centers and received from 44. In all, 808 patients underwent transplantation between 2000 and 2020. One-, 5- and 10-year PS was 84%, 77%, and 68%, and GS was 79%, 70%, and 62%, respectively. Both significantly improved compared to outcomes before 2000 ( p < 0.001). Median follow-up was 50 months and retransplantation rate was 12%. Recipient age (aHR:1.04,95%CI:1.02-1.06) and MELD score (aHR:1.04,95%CI:1.01-1.06), especially above 30, were associated with worse PS, while male sex had better outcomes (aHR:0.63,95%CI:0.41-0.96). Donor age was associated with worse PS (aHR:1.01,95%CI:1.00-1.03) and GS (aHR:1.02,95%CI:1.01-1.03). In 353 patients (44%) with supplemental data, 33% had myeloproliferative neoplasm, 20% underwent TIPS pre-LT, and 85% used anticoagulation post-LT. Post-LT anticoagulation was associated with improved PS (aHR:0.29,95%CI:0.16-0.54) and GS (aHR:0.48,95%CI:0.29-0.81). Hepatic artery thrombosis and portal vein thrombosis (PVT) occurred in 9% and 7%, while recurrent BCS was rare (3%). CONCLUSIONS: LT for BCS results in excellent patient- and graft-survival. Older recipient or donor age and higher MELD are associated with poorer outcomes, while long-term anticoagulation improves both patient and graft outcomes.

Clinical outcomes after transplantation of domino grafts or standard deceased donor livers: a systematic review and meta-analysis.

BACKGROUND AND AIM: Domino liver transplantation (DLT) utilizes otherwise discarded livers as donor grafts for another recipients. It is unclear whether DLT has less favorable outcomes compared to deceased donor liver transplantation (DDLT). We aimed to assess the outcomes of DLT compared to DDLT. METHODS: MEDLINE, Embase, and Web of Science database were searched to identify studies comparing outcomes after DLT with DDLT. Data were pooled using random-effects modeling, evaluating odds ratios (OR) or mean difference (MD) for outcomes including waiting list time, severe hemorrhage, intensive care unit (ICU), length hospital stay (LOS), rejection, renal, vascular, and biliary events, and recipient survival at 1, 3, 5, and 10 years. RESULTS: Five studies were identified including 945 patients (DLT = 409, DDLT = 536). The DLT recipients were older compared to the DDLT group (P = 0.04), and both cohorts were comparable regarding lab MELD, hepatocellular carcinoma, and waitlist time. There were no differences in vascular (OR: 1.60, P = 0.39), renal (OR: 0.62, P = 0.24), biliary (OR: 1.51, P = 0.21), severe hemorrhage (OR: 1.09, P = 0.86), rejection (OR: 0.78, P = 0.51), ICU stay (MD: 0.50, P = 0.21), or LOS (MD: 1.68, P = 0.46) between DLT and DDLT. DLT and DDLT were associated with comparable 1-year (78.9% vs 80.4%; OR: 1.03, P = 0.89), 3-year (56.2% vs 54.1%; OR: 1.35, P = 0.07), and 10-year survival (6.5% vs 8.5%; OR: 0.8, P = 0.67) rates. DLT was associated with higher 5-year survival (41.6% vs 36.4%; OR: 1.70; P = 0.003) compared to DDLT, which was not confirmed at sensitivity analysis. CONCLUSION: This meta-analysis of the best available evidence (Level 2a) demonstrated that DLT and DDLT have comparable outcomes. As indications for liver transplantation expand, future high-quality research is encouraged to increase the DLT numbers in clinical practice, serving the growing waiting list candidates, with the caveat of uncertain de novo disease transmission risks.

Meta-analysis of fenestrating versus reconstituting subtotal cholecystectomy in the management of difficult gallbladder.

AIMS: To evaluate comparative outcomes of fenestrating and reconstituting subtotal cholecystectomy (STC) in patients with difficult gallbladder. METHODS: A systematic search of electronic data sources and bibliographic reference lists were conducted. All comparative studies reporting outcomes of laparoscopic fenestrating and reconstituting STC were included and their risk of bias were assessed using ROBINS-I tool. RESULTS: Seven comparative studies were included enrolling 590 patients undergoing laparoscopic STC using either fenestrating (n = 353) or reconstituting (n = 237) approaches. Although fenestrating STC was associated with a significantly higher rate of bile leak (OR: 2.47, p = 0.007) compared to reconstituting STC, both approaches were comparable in terms of resolution of bile leak without (RD: -0.02, p = 0.86) or with (OR: 1.84, p = 0.40) postoperative ERCP. Moreover, there was no significant difference in development of bile duct injury (RD: -0.02, p = 0.16), need for postoperative ERCP (OR: 1.36, p = 0.49), wound infection (RD: 0.03, p = 0.27), re-operation (OR: 0.95, p = 0.95), gallbladder remnant cholecystitis (OR: 0.21, p = 0.09) or need for completion cholecystectomy (RD: 0.01, p = 0.59) between two groups. CONCLUSIONS: Fenestrating STC is associated with a higher risk of bile leak than the reconstructing technique. This issue can be mitigated by routine use of drains, delayed drain removal, and in selected cases endoscopic therapy. We encourage the fenestrating approach considering trends in improved short- and long-term outcomes.

Improving reduced-order models through nonlinear decoding of projection-dependent outputs.

A fundamental hindrance to building data-driven reduced-order models (ROMs) is the poor topological quality of a low-dimensional data projection. This includes behavior such as overlapping, twisting, or large curvatures or uneven data density that can generate nonuniqueness and steep gradients in quantities of interest (QoIs). Here, we employ an encoder-decoder neural network architecture for dimensionality reduction. We find that nonlinear decoding of projection-dependent QoIs, when embedded in a dimensionality reduction technique, promotes improved low-dimensional representations of complex multiscale and multiphysics datasets. When data projection (encoding) is affected by forcing accurate nonlinear reconstruction of the QoIs (decoding), we minimize nonuniqueness and gradients in representing QoIs on a projection. This in turn leads to enhanced predictive accuracy of a ROM. Our findings are relevant to a variety of disciplines that develop data-driven ROMs of dynamical systems such as reacting flows, plasma physics, atmospheric physics, or computational neuroscience.

Global land and water limits to electrolytic hydrogen production using wind and solar resources.

Proposals for achieving net-zero emissions by 2050 include scaling-up electrolytic hydrogen production, however, this poses technical, economic, and environmental challenges. One such challenge is for policymakers to ensure a sustainable future for the environment including freshwater and land resources while facilitating low-carbon hydrogen production using renewable wind and solar energy. We establish a country-by-country reference scenario for hydrogen demand in 2050 and compare it with land and water availability. Our analysis highlights countries that will be constrained by domestic natural resources to achieve electrolytic hydrogen self-sufficiency in a net-zero target. Depending on land allocation for the installation of solar panels or wind turbines, less than 50% of hydrogen demand in 2050 could be met through a local production without land or water scarcity. Our findings identify potential importers and exporters of hydrogen or, conversely, exporters or importers of industries that would rely on electrolytic hydrogen. The abundance of land and water resources in Southern and Central-East Africa, West Africa, South America, Canada, and Australia make these countries potential leaders in hydrogen export.

Risk factors for postoperative complications after adrenalectomy for phaeochromocytoma: multicentre cohort study.

BACKGROUND: To determine the incidence and risk factors for postoperative complications and prolonged hospital stay after adrenalectomy for phaeochromocytoma. METHODS: Demographics, perioperative outcomes and complications were evaluated for consecutive patients who underwent adrenalectomy for phaeochromocytoma from 2012 to 2020 in nine high-volume UK centres. Odds ratios were calculated using multivariable models. The primary outcome was postoperative complications according to the Clavien---Dindo classification and secondary outcome was duration of hospital stay. RESULTS: Data were available for 406 patients (female n = 221, 54.4 per cent). Two patients (0.5 per cent) had perioperative death, whilst 148 complications were recorded in 109 (26.8 per cent) patients. On adjusted analysis, the age-adjusted Charlson Co-morbidity Index ≥3 (OR 8.09, 95 per cent c.i. 2.31 to 29.63, P = 0.001), laparoscopic converted to open (OR 10.34, 95 per cent c.i. 3.24 to 36.23, P <0.001), and open surgery (OR 11.69, 95 per cent c.i. 4.52 to 32.55, P <0.001) were independently associated with postoperative complications. Overall, 97 of 430 (22.5 per cent) had a duration of stay ≥5 days and this was associated with an age-adjusted Charlson Co-morbidity Index ≥3 (OR 4.31, 95 per cent c.i. 1.08 to 18.26, P = 0.042), tumour size (OR 1.15, 95 per cent c.i. 1.05 to 1.28, P = 0.006), laparoscopic converted to open (OR 32.11, 95 per cent c.i. 9.2 to 137.77, P <0.001), and open surgery (OR 28.01, 95 per cent c.i. 10.52 to 83.97, P <0.001). CONCLUSION: Adrenalectomy for phaeochromocytoma is associated with a very low mortality rate, whilst postoperative complications are common. Several risk factors, including co-morbidities and operative approach, are independently associated with postoperative complications and/or prolonged hospitalization, and should be considered when counselling patients.