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Purpose: This study aims to evaluate the accuracy of point-based registration (PBR) when used for augmented reality (AR) in laparoscopic liver resection surgery. Material and methods: The study was conducted in three different scenarios in which the accuracy of sampling targets for PBR decreases: using an assessment phantom with machined divot holes, a patient-specific liver phantom with markers visible in computed tomography (CT) scans and in vivo, relying on the surgeon's anatomical understanding to perform annotations. Target registration error (TRE) and fiducial registration error (FRE) were computed using five randomly selected positions for image-to-patient registration. Results: AR with intra-operative CT scanning showed a mean TRE of 6.9 mm for the machined phantom, 7.9 mm for the patient-specific phantom and 13.4 mm in the in vivo study. Conclusions: AR showed an increase in both TRE and FRE throughout the experimental studies, proving that AR is not robust to the sampling accuracy of the targets used to compute imageto-patient registration. Moreover, an influence of the size of the volume to be register was observed. Hence, it is advisable to reduce both errors due to annotations and the size of registration volumes, which can cause large errors in AR systems.

Pancreatic cancer is the deadliest of the gastrointestinal tract with 5-year survival rates of less than 5%. Given common asymptomatic early disease course, most patients (50%) present with an already metastatic disease, while only 20% can undergo potentially curative resection. The remaining 30% present with locally advanced disease, defined as extended vascular encasement, where the risk of surgical therapy often outweighs its benefits. Traditional thermal local ablative modalities (RFA, MWA, or cryotherapy) have the disadvantage that they are not applicable in proximity to vital vascular structures, which are abundant in the peripancreatic region. Irreversible electroporation (IRE) is an emerging non-thermal alternative that induces apoptosis of tumor cells by the delivery of short repetitive impulses of high-voltage electric current. Given its mostly non-thermal modality, IRE is not hampered by a heat-sink effect and is applicable with little risk around vascular structures, bile and pancreatic ducts. Recent research suggests that local tumor destruction through IRE improves overall survival, progression-free survival and quality of life in patients with locally advanced pancreatic cancer.

Background: While hypothermic perfusion of the liver has been shown to improve parenchymal tolerance to complex resections in patients requiring prolonged hepatic vascular exclusion (HVE), the benefit of associated veno-venous bypass (VVB) in this setting remains poorly evaluated. Methods: All patients undergoing liver resection requiring HVE for at least 60 minutes were retrospectively reviewed. Perioperative outcomes were compared between patients with (VVB+) or without VVB (VVB-). Results: Twenty-seven patients had liver resection with HVE and hypothermic perfusion of the liver between 2006 and 2017, including 13 (48%) VVB+ and 14 (52%) VVBpatients. Demographic characteristics and indications for liver resection were similar between the two groups. Median HVE exclusion durations were similar in (96 vs. 75 min, p=0.72) VVB+ and VVB-patients. VVB+ patients had increased operative time (460 vs. 375 min, p=0.05) but decreased amount of transfusion (p=0.05).. Five (19%) patients died postoperatively from liver failure (n=4) or sepsis (n=1), without significant difference between VVB+ and VVB-patients (p=0.56). Postoperative major morbidity rate (Dindo-Clavien 3-4, 30% vs. 50%) was not different between the two groups. The rates of liver failure, haemorrhage, renal insufficiency, and sepsis were not different between the two groups but VVB-patients experienced increased rates of respiratory complications than VVB+ patients (64% vs. 15%, respectively, p=0.01). Conclusion: During liver resection under HVE and hypothermic perfusion of the liver, the use of VVB allows reducing red blood cells transfusions and postoperative respiratory complications. VVB should be recommended in case of liver resection with prolonged HVE.

The insertion of ablation needles towards pancreatic tumors demands excellent anatomical knowledge and interdisciplinary skills from the medical professional. While the placement of a single needle next to the structures at risk surrounding the pancreas is considered a challenging task, irreversible electroporation requires multiple needles to be placed in parallel at a specific location. Minimally invasive procedures complicate the already ambitious procedure, yet the ablation method bears potential to increase the overall survival for patients with locally advanced pancreatic cancer. Current studies require more clinical evidence regarding the efficacy of irreversible electroporation in pancreatic cancer by means of randomized controlled, multicenter trials. However, the ablation treatment is currently applied in expert centers only, which is due to the complex task of the needle placement. Computer-assisted surgery has shown its potential in different fields of applications to improve the targeting of diseased tissue and the confidence of the medical professional. The application of computer-assisted needle navigation for pancreatic cancer ablation holds the prospect to make the procedure more reproducible and safer.

The appropriate procedure for closure of the remnant pancreatic stump in distal pancreatectomy (DP) remains unresolved. The purpose of this study was to compare the incidence of pancreatic fistula (PF) among the 3 methods, and to determine the risk factors for PF after DP. Methods: Between July 2009 and December 2016, 66 patients underwent pancreatic stump closure with 1 of 3 methods: the clamp-crushing method (n = 26), ultrasonic scissors (n = 18), and a reinforced stapler (n = 22). Results: There were significant differences in the incidence of PF (clamp-crushing method [38%] vs ultrasonic scissors [61%] vs reinforced stapler [9%], p< 0.001), and in the incidence of postoperative intra-abdominal hemorrhage (clamp-crushing method [0%] vs ultrasonic scissors [17%] vs reinforced stapler [0%] p = 0.047). A multivariate analysis revealed that intraoperative blood loss (605 mL), pancreatic thickness (11 mm), and the stump closure method were independent risk factors for PF after DP (p = 0.03, p = 0.001, p=0.018 respectively). Conclusion: The use of a reinforced stapler for the transection of the pancreas can reduce PF after DP. Intraoperative blood loss (605 mL), pancreatic thickness (11 mm), and the stump closure method remained as independent risk factors for PF after DP.