Delayed post-pancreatectomy hemorrhage and bleeding recurrence after percutaneous endovascular treatment: risk factors from a bi-centric study of 307 consecutive patients.

PURPOSE: Delayed post-pancreatectomy hemorrhage (PPH) is still one of the most dreaded complications after pancreatic surgery. Its management is now focused on percutaneous endovascular treatments (PETs). METHODS: Between 2013 and 2019, 307 patients underwent pancreatic resection. The first endpoint of this study was to determine predictive factors of delayed PPH. The second endpoint was to describe the management of intra-abdominal abscesses (IAA). The third endpoint was to identify risk factors of bleeding recurrence after PET. Patients were divided into two cohorts: A retrospective analysis was performed ("cohort 1," "learning set") to highlight predictive factors of delayed PPH. Then, we validated it on a prospective maintained cohort, analyzed retrospectively ("cohort 2," "validation set"). Second and third endpoints studies were made on the entire cohort. RESULTS: In cohort 1, including 180 patients, 24 experienced delayed PPH. Multivariate analysis revealed that POPF diagnosis on postoperative day (POD) 3 (p=0.004) and IAA (p=0.001) were independent predictive factors of delayed PPH. In cohort 2, association of POPF diagnosis on POD 3 and IAA was strongly associated with delayed PPH (area under the curve [AUC] 0.80; 95% confidence interval [CI] [0.59-0.94]; p=0.003). Concerning our second endpoint, delayed PPH occurred less frequently in patients who underwent postoperative drainage procedure than in patients without IAA drainage (p=0.002). Concerning our third endpoint, a higher body mass index (BMI) (p=0.027), occurrence of postoperative IAA (p=0.030), and undrained IAA (p=0.011) were associated with bleeding recurrence after the first PET procedure. CONCLUSION: POPF diagnosis on POD 3 and intra-abdominal abscesses are independent predictive factors of delayed PPH. Therefore, patients presenting an insufficiently drained POPF leading to intra-abdominal abscess after pancreatic surgery should be considered as a high-risk situation of delayed PPH. High BMI, occurrence of postoperative IAA, and undrained IAA were associated with recurrence of bleeding after PET.

Prospective study on predictability of complications by pancreatic surgeons.

PURPOSE: We evaluated the intuition of expert pancreatic surgeons, in predicting the associated risk of pancreatic resection and compared this "intuition" to actual operative follow-up. The objective was to avoid major complications following pancreatic resection, which remains a challenge. METHODS: From January 2015 to February 2018, all patients who were 18 years old or more undergoing a pancreatic resection (pancreaticoduodenectomy [PD], distal pancreatectomy [DP], or central pancreatectomy [CP]) for pancreatic lesions were included. Preoperatively and postoperatively, all surgeons completed a form assessing the expected potential occurrence of clinically relevant postoperative pancreatic fistula (CR-POPF: grade B or C), postoperative hemorrhage, and length of stay. RESULTS: Preoperative intuition was assessed for 101 patients for 52 PD, 44 DP, and 5 CP cases. Overall mortality and morbidity rates were 6.9% (n = 7) and 67.3% (n = 68), respectively, and 38 patients (37.6%) developed a POPF, including 27 (26.7%) CR-POPF. Concordance between preoperative intuition of CR-POPF occurrence and reality was minimal, with a Cohen's kappa coefficient (κ) of 0.175 (P value = 0.009), and the same result was obtained between postoperative intuition and reality (κ = 0.351; P < 0.001). When the pancreatic parenchyma was hard, surgeons predicted the absence of CR-POPF with a negative predictive value of 91.3%. However, they were not able to predict the occurrence of CR-POPF when the pancreas was soft (positive predictive value 48%). CONCLUSIONS: This study assessed for the first time the surgeon's intuition in pancreatic surgery, and demonstrated that pancreatic surgeons cannot accurately assess outcomes except when the pancreatic parenchyma is hard.

Experimental Procedure of Compression Anastomosis Using Fragmented Rings: A Porcine Model.

BACKGROUND: Compression anastomosis has been recently abandoned because of a nonsuperiority compared to stapling anastomosis. Nonremoval of the rings has frequently been reported and this technique does not support a routine use. The aim of this experimental study was to assess the feasibility of anastomosis using compression with a device consisting of fragmented rings. METHODS: A new compression device, the "Anastocom," was compared to standard double-stapled colocolonic anastomosis in 2 groups of 8 pigs. In each group, colocolonic anastomosis was performed with a circular stapler (DST Series EEA Staplers) in 4 pigs and with the Anastocom device for the other 4 pigs. RESULTS: The anastomotic rings were expelled between postoperative day 7 and day 13 from the 4 animals sacrificed at day 30. The anastomosis was clean and intact in all pigs. After sacrifice, there was no difference in the bursting pressure at day 7 ( P = .226) or at day 30 ( P = .885) between the 2 types of anastomosis. After sacrifice at day 7, the mean bursting pressure values for the Anastocom and EEA anastomoses were 128.6 mm Hg (range 119-143 mm Hg) and 218.9 mm Hg (range 84-240 mm Hg), respectively. After sacrifice at day 30, the mean bursting pressure values for the Anastocom and EEA anastomoses were 111 mm Hg (range 59-234 mm Hg) and 105 mm Hg (range 81-130 mmHg), respectively. CONCLUSION: No bowel obstruction was observed with Anastocom. This fragmentation mechanism should better prevent nonexpulsion compared to basic compression anastomosis.

Three-dimensional variability of the mesentery and the superior mesenteric artery: application to virtual trauma modeling.

INTRODUCTION: Trauma is a major cause of death worldwide, mainly affecting a young male population. Blunt trauma of the abdomen can cause a trauma of the mesentery in 5 % of cases. Rapid decelerations and injuries by seat belts are the most common pathophysiological mechanisms. Three-dimensional anatomical scanning of the mesentery and gastrointestinal tract is the first essential step in modeling abdominal trauma in an attempt to understand the pathophysiology of mesenteric lesions and to improve the safety features of vehicles. OBJECTIVE OF THE STUDY: To analyze the individual variability of the mesentery and the superior mesenteric artery (SMA) from medical imaging and to develop a three-dimensional customizable finite element model. MATERIALS AND METHODS: In this retrospective study, one hundred abdominopelvic injected CT scans were analyzed from healthy patients. The evaluation criteria of the mesentery were its volume (total and the distribution of adipose tissue/non adipose tissue), the length of the SMA and the distance between duodenojejunal angle (DJA) and the ileocecal junction (ICJ). The variability of these measures has been studied by demographic (age and gender) and morphologic (height evaluated by the T11-L4 distance, the waist circumference and the thickness of the subcutaneous adipose tissue). RESULTS: Mean mesenteric volume was 644 cm(3) (ranges from 89 to 1,869 cm(3)), and the mean length of the SMA was 224.9 mm (ranges from 138.4 to 312.3). There was a statistically significant association between waist circumference and the total volume of the mesentery, its fat component and non fat component (p < 0.001). Waist circumference was the only morphological parameter associated with the length of the superior mesenteric artery and the length of the DJA to ICJ (p < 0.001). Subcutaneous adipose tissue and female sex were statistically associated with total mesentery volume (respectively, p = 0.005 and p = 0.001). Age was an independent predictor of the increased volume of the mesentery and the length of the SMA. The height of the subject changes the length of the SMA (p = 0.001). CONCLUSION: The assessment of the mesenteric variability highlighted three factors associated with its size and length: age, sex, and waist circumference. These parameters have to be taken into account to personalize numerical model in the area of virtual trauma.

Three-dimensional determination of variability in colon anatomy: applications for numerical modeling of the intestine.

BACKGROUND: Precise knowledge of variability in colonic anatomy is of great importance for numerical modeling studies of the abdomen. This knowledge would allow the creation of personalized models for the gastrointestinal tract used for surgical simulations or in studies of virtual trauma. MATERIALS AND METHODS: To determine the colonic configuration in the general population and define its variability by gender, age, and corpulence, the layout of the colon was determined via the following reference points: ileocecal junction, left and right colonic flexures, and colosigmoid junction (CSJ). Three-dimensional coordinates for each point were recorded on scanned sections of 100 healthy adults to examine the colonic layout under physiological conditions. Coordinates were repositioned in a new anatomical reference for comparison. The average points' coordinates, standard deviations, and distances between them were compared for each group. RESULTS: The right colonic flexure was the most variable point. The CSJ was the least variable. Gender affected mainly the height of the colonic flexures and the length of its segments. Age affected the length of the transverse mesocolon root. Corpulence affected both the position of the ileocecal and CSJs and the length of the right colon. Differences in size and perivisceral fat distribution between groups explained these differences. Three-dimensional anatomical models of the colon were defined for each group by statistical equations. CONCLUSION: These equations, combined with data concerning the actual lengths of the colonic segments, enable reconstruction of different anatomical models of the colon that are representative according to gender, age, and corpulence.

Biomechanic study of the human liver during a frontal deceleration.

BACKGROUND: Mechanisms of hepatic injury remain poorly understood. Surgical literature reports some speculative theories that have never been proved. The aim of this study was to examine the behavior of the liver during brutal frontal deceleration. METHODS: Six trunks, removed from human cadavers, underwent free falls at 4, 6, and 8 meters per second (mps). Accelerometers were positioned in the two lobes of the liver, in front of the vertebra L2, and in the retro hepatic inferior vena cava. Relative motions of the lobes of the liver and of the two other anatomic marks were observed. In parallel, numerical simulations of this experiment have been performed using a finite element model. RESULTS: In the direction of impact, the vertebra L2 had no considerable displacement with the inferior vena cava. There was a noteworthy displacement between the two hepatic lobes. The left hepatic lobe had a large relative displacement with the vertebra L2 and the inferior vena cava. The right hepatic lobe was more stable with the vertebra L2 and the inferior vena cava. Numerical simulation of the same protocol underlined a rotation effect of the liver to the left around the axis of the inferior vena cava. CONCLUSIONS: These results support the surgical data. They highlight a crucial zone and explain how dramatic lacerations between the two lobes of the liver can occur.

3D reconstruction of the diaphragm for virtual traumatology.

This study lies within the scope of passive road safety, and more particularly injury mechanisms of the abdominal area. The finite element modeling, which makes it possible to simulate a road accident and to observe the possible bone fractures or internal tissue injuries, allows large projections in the comprehension of injury mechanisms. However, the digital models already available and used in accidentology do not offer as one very simplified description of the diaphragm, as well for its geometry as for its bracing aspect and the modifications that this could induce in the behavior of abdominal organs and vessels at impact. In order to develop an accurate model of diaphragm for road safety research, a 3D reconstruction was performed, based on a sitting post-mortem Human subject sections. The resulting geometry was then turned into a segmented mechanical component (using the finite element method) and included in a full human model already available. The result is a valuable tool to improve the knowledge of injury mechanisms involved in car crashes at the abdominal level.

An experimental cadaveric study for a better understanding of blunt traumatic aortic rupture.

BACKGROUND: Blunt traumatic aortic rupture (BTAR) is a common catastrophic injury leading to death. Considerable uncertainty remains regarding the pathogenic cause. This study examines the comportment of the heart and the aorta during a frontal deceleration. METHODS: Accelerometers were placed in the right ventricle of the heart, the aorta, the sternum, and the spine of six trunks removed from human cadavers. Different vertical decelerations were applied to cadavers and the relative motion of these organs was studied (19 tests). RESULTS: The deceleration recorded in the isthmus of the aorta was always higher that the one recorded in the heart (p < 0.05). The difference of deceleration was 17% and increased with the speed's fall (extremes 5-25%). There was no significant difference of deceleration between the bony structures of the thorax. These results experimentally demonstrate for the first time that the fundamental mechanism of BTAR is sudden stretching of the isthmus of the aorta. CONCLUSION: Four mechanisms are suspected to explain the location of the rupture: two hemodynamic mechanism (sudden increase of intravascular pressure and the water-hammer effect), and two physical mechanisms (sudden stretching of the isthmus and the osseous pinch). A greater understanding of the mechanism of this injury could improve vehicle safety leading to a reduction in its incidence and severity. Future work in this area should include the creation of an inclusive, dynamic model of computer-based modeling systems. This study provides for the first time physical demonstration and quantification of the stretching of the isthmus, leading to a computerized model of BTAR.