Learning surgical knot tying and suturing technique - effects of different forms of training in a controlled randomized trial with dental students

Objective

The acquisition of surgical skills requires motor learning. A special form of this is intermanual transfer by transferring motor skills from the nondominant hand (NDH) to the dominant hand (DH). The purpose of this study was to determine the learning gains that can be achieved for the DH by training with the DH, the NDH, and by non-surgical alternative training (AT).

Methods

124 preclinical (n=62) and clinical (n=62) dental students completed surgical knot tying and suturing technique training with the DH, with the NDH, and an AT in a controlled randomized trial.

Results

A statistically significant learning gain in knot tying and suture technique with the DH was evident only after training with the DH when compared to training with the NDH (p<0.001 and p=0.004, respectively) and an AT (p=0.001 and p=0.010, respectively). Of those students who achieved a learning gain ≥4 OSATS points, 46.4% (n=32) benefited in their knot tying technique with the DH from training with the DH, 29.0% (n=20) from training with the NDH, and 24.6% (n=17) from an AT while 45.7% (n=32) benefited in their suturing technique with the DH from training with the DH, 31.4% (n=22) from training with the NDH, and 22, 9% (n=16) from an AT.

Conclusions

Training with the DH enabled significantly better learning gains in the surgical knot tying and suturing techniques with the DH.

Interleukin-18 and High-Mobility-Group-Protein B1 are Early and Sensitive Indicators for Cell Damage During Normothermic Machine Perfusion after Prolonged Cold Ischemic Storage of Porcine Liver Grafts

In the era of organ machine perfusion, experimental models to optimize reconditioning of (marginal) liver grafts are needed. Although the relevance of cytokine signatures in liver transplantation has been analyzed previously, the significance of molecular monitoring during normothermic machine perfusion (NMP) remains elusive. Therefore, we developed a porcine model of cold ischemic liver graft injury after prolonged static cold storage (SCS) and subsequent NMP: Livers obtained from ten minipigs underwent NMP for 6 h directly after procurement (control group) or after 20 h of SCS. Grafts after prolonged SCS showed significantly elevated AST, ALT, GLDH and GGT perfusate concentrations, and reduced lactate clearance. Bile analyses revealed reduced bile production, reduced bicarbonate and elevated glucose concentrations after prolonged SCS. Cytokine analyses of graft perfusate simultaneously demonstrated an increase of pro-inflammatory cytokines such as Interleukin-1α, Interleukin-2, and particularly Interleukin-18. The latter was the only significantly elevated cytokine compared to controls, peaking as early as 2 h after reperfusion (11,012 ng/ml vs. 1,493 ng/ml; p = 0.029). Also, concentrations of High-Mobility-Group-Protein B1 were significantly elevated after 2 h of reperfusion (706.00 ng/ml vs. 148.20 ng/ml; p < 0.001) and showed positive correlations with AST (r² = 0.846) and GLDH (r² = 0.918) levels. Molecular analyses during reconditioning of liver grafts provide insights into the degree of inflammation and cell damage and could thereby facilitate future interventions during NMP reducing acute and chronic graft injury.

Preoperative leukocytosis is an independent risk factor for morbidity and survival after resection of colorectal liver metastases

BACKGROUND

Although surgical resection of colorectal liver metastases (CRLM) remains to be the only option for long term survival, traditional surgical concepts have been challenged by the introduction of the liver first approach or neoadjuvant chemotherapy in resectable CRLM and interventional therapies. The aim of this study was to identify prognostic factors for postoperative morbidity and survival and to externally evaluate the recently introduced resection severity index (RSI), in order to optimize patient selection and treatment strategies.

METHODS

This is a retrospective single centre analysis of 213 patients undergoing surgery for CRLM in curative intent between January 2010 and December 2018.

RESULTS

Median follow up after liver resection was 28.56 (0.01-111.46) months. Severe postoperative complications (Clavien-Dindo ≥ IIIa) were observed in 46 (21.6%) cases. Preoperative leukocytosis (OR: 3.114, CI-95%: 1.089-8.901; p = 0.034) and operation time in minutes (OR: 1.007, CI-95%: 1.002-1.011; p = 0.002) were determined as independent risk factors. Overall survival (OS) was 46.68 months with a 5-year survival rate of 40.5%. Independent prognostic factors were preoperative leukocytosis (HR: 2.358, CI-95%: 1.170-4.752; p = 0.016), major hepatectomy (HR: 1.741, CI-95%: 1.098-2.759; p = 0.018) and low grading of the primary intestinal tumour (HR: 0.392, CI-95%: 0.231-0.667; p < 0.001). The RSI (ASAT (U/l) divided by Quick (%) multiplied by the extent of liver resection in points) was identified as independent risk factor for OS only in patients without neoadjuvant chemotherapy.

CONCLUSIONS

Detection of leukocytosis in patients prior resection of CRLM was associated with increased postoperative morbidity and decreased OS and could therefore prove valuable for perioperative risk stratification.

Impact of perioperative blood transfusions on postoperative renal function and survival after resection of colorectal liver metastases

Background and aims

Recent studies focusing on thoracic surgery suggest postoperative kidney injury depending on the amount of perioperative blood transfusions. Data investigating similar effects after resection of colorectal liver metastases (CRLM) are not available. Aim of this study was therefore to evaluate the influence of perioperative blood transfusions on postoperative renal function and survival after resection of CRLM.

Methods

Seven hundred twenty-seven cases of liver resection for CRLM were retrospectively analyzed. Renal function was measured via estimated glomerular filtration rate (eGFR) and a postoperative decline of ≥ 10% was considered substantial. Potential influences on postoperative kidney function were assessed using univariable and multivariable logistic regression analyses. Cox-regression analyses were performed to estimate the impact on overall survival (OS).

Results

Preoperative impaired kidney function (p = 0.001, OR 2.477) and transfusion of > 2 units of packed red blood cells (PRBC) (p = 0.046; OR 1.638) were independently associated with an increased risk for ≥ 10% loss of renal function. Neither a pre-existing renal impairment, nor the additional loss of renal function were associated with reduced survival. Chemotherapies in the context of primary colorectal cancer treatment (p = 0.002), age > 70 years at liver resection (p = 0.005), number (p = 0.001), and size of metastases > 50 mm (p = 0.018), duration of resection > 120 min (p = 0.006) and transfusions of > 2 units of PRBC (p = 0.039) showed a negative independent influence on OS.

Conclusion

The results demonstrate a negative impact of perioperative blood transfusions on the postoperative renal function and OS. Hence, efforts to reduce blood transfusions should be intensified.

Antibiotic-Resistant Bacteria Colonizing the Bile Duct Are Associated with Increased Morbidity and Mortality after Resection of Extrahepatic Cholangiocarcinoma

Background: Patients with extrahepatic cholangiocarcinoma (CCA) face considerable morbidity including septic complications after surgery. The aim of this study was to characterize the bacterial spectrum of the common hepatic duct (CHD) and its clinical relevance regarding morbidity and mortality after resection of extrahepatic CCA. Methods: We retrospectively analyzed data from 205 patients undergoing surgery for extrahepatic CCA in our department between January 2000 and March 2015. Patients were reviewed for pre-operative medical conditions, biliary bacterial flora obtained from intra-operative swabs, different septic complications, and post-operative outcome. Results: Bacterial colonization of the CHD was observed in 84.9% of the patients, with Enterococcus faecalis being detected most frequently (28.3%). Wound infections occurred in 30.7% of patients. Bacterial flora of the CHD and of the post-operatively colonized wounds coincided in 51.5% and of intra-abdominal swabs obtained during surgical revisions in 40.0%. Ciprofloxacin-resistant bacteria in the CHD were identified as independent risk factor for wound infections (odds ratio [OR], 3.330; 95% confidence interval [CI], 1.771-6.263; p < 0.001) and for complications requiring surgical revision (OR, 2.417; 95% CI, 1.288-4.539; p = 0.006). Most important independent risk factors for intra-hospital mortality were ampicillin-sulbactam-resistant bacteria in the CHD (OR, 3.969; 95% CI, 1.515-10.399; p = 0.005) and American Society of Anesthesiologists (ASA) grading >2 (OR, 2.936; 95% CI, 1.337-6.451; p = 0.007). Conclusions: Antibiotic-resistant bacteria from the CHD are associated with increased morbidity and mortality in patients undergoing resection for extrahepatic CCA.

Proposal of a New Definition of "Very Early" Intrahepatic Cholangiocarcinoma-A Retrospective Single-Center Analysis

Intrahepatic cholangiocarcinoma (ICC) is a rare disease with poor outcome, despite advances in surgical and non-surgical treatment. Recently, studies have reported a favorable long-term outcome of “very early” ICC (based on tumor size and absence of extrahepatic disease) after hepatic resection and liver transplantation, respectively. However, the prognostic value of tumor size and a reliable definition of early disease remain a matter of debate. Patients undergoing resection of histologically confirmed ICC between February 1996 and January 2021 at our institution were reviewed for postoperative morbidity, mortality, and long-term outcome after being retrospectively assigned to two groups: “very early” (single tumor ≤ 3 cm) and “advanced” ICC (size > 3 cm, multifocality or extrahepatic disease). A total of 297 patients were included, with a median follow-up of 22.8 (0.1–301.7) months. Twenty-one (7.1%) patients underwent resection of “very early” ICC. Despite the small tumor size, major hepatectomies (defined as resection of ≥3 segments) were performed in 14 (66.7%) cases. Histopathological analyses revealed lymph node metastases in 5 (23.8%) patients. Patients displayed excellent postoperative outcome compared to patients with “advanced” disease: intrahospital mortality was not observed, and patients displayed superior long-term survival, with a 5-year survival rate of 58.2% (versus 24.3%) and a median postoperative survival of 62.1 months (versus 25.3 months; p = 0.013). In conclusion, although the concept of a “very early” ICC based solely on tumor size is vague as it does not necessarily reflect an aggressive tumor biology, our proposed definition could serve as a basis for further studies evaluating the efficiency of either surgical resection or liver transplantation for this malignant disease.

Recurrent Hurthle cell thyroid carcinoma does not preclude long-term survival: a case report and review of the literature

Background

Follicular thyroid carcinoma is the second most common malignancy of the thyroid gland. In 2016, the so-called Hurthle cell thyroid carcinoma, formerly known as the oxyphilic variant of the follicular thyroid carcinoma, was reclassified by the World Health Organization as a separate pathological entity, which accounts for approximately 3% of all thyroid cancers. Although Hurthle cell thyroid carcinomas are known for their more aggressive tumor biology, metastases are observed in a minority of cases, and long-term survival can be expected. However, disseminated disease is often associated with poor outcome.

Case presentation

In the presented case, a 63-year-old Caucasian female was incidentally diagnosed with Hurthle cell thyroid carcinoma after undergoing hemithyroidectomy for a nodular goiter. Following completion thyroidectomy, two courses of radioactive iodine therapy were administered. After 4 years of uneventful follow-up, the patient gradually developed metastases in five different organs, with the majority representing unusual sites, such as heart, kidney, and pancreas over a course of 14 years. The lesions were either treated with radioactive iodine therapy or removed surgically, depending on iodine avidity.

Conclusion

Follicular and Hurthle cell thyroid carcinoma are known to potentially spread hematogenously to typical sites, such as lung or bones, however; unusual metastatic sites as presented in our case can also be observed. A search of the literature revealed only scattered reports on patients with multiple metastases in unusual locations. Furthermore, the observed long-term survival of our patient is contradictory to the existing data. As demonstrated, recurrent disease may appear years after the initial diagnosis, emphasizing the importance of consistent aftercare. Radioactive iodine therapy, extracorporeal radiation therapy, and surgical metastasectomy are central therapeutic components. In summary, our case exemplifies that thorough aftercare and aggressive treatment enables long-term survival even in recurrent Hurthle cell thyroid carcinoma displaying unusual multisite metastases.

Simultaneous heart-kidney transplantation results in respectable long-term outcome but a high rate of early kidney graft loss in high-risk recipients - a European single center analysis

BACKGROUND

In spite of renal graft shortage and increasing waiting times for transplant candidates, simultaneous heart and kidney transplantation (HKTx) is an increasingly performed procedure established for patients with combined end-stage cardiac and renal failure. Although data on renal graft outcome in this setting is limited, reports on reduced graft survival in comparison to solitary kidney transplantation (KTx) have led to an ongoing discussion of adequate organ utilization.

METHODS

This retrospective study was conducted to evaluate prognostic factors and outcomes of 27 patients undergoing HKTx in comparison to a matched cohort of 27 patients undergoing solitary KTx between September 1987 and October 2019 in one of Europe's largest transplant centers.

RESULTS

Median follow-up was 100.33 (0.46-362.09) months. Despite lower five-year kidney graft survival (62.6% versus 92.1%; 111.73 versus 183.08 months; p = 0.189), graft function and patient survival (138.90 versus 192.71 months; p = 0.128) were not significantly inferior after HKTx in general. However, in case of prior cardiac surgery requiring sternotomy we observed significantly reduced early graft and patient survival (57.00 and 94.09 months, respectively) when compared to patients undergoing solitary KTx (183.08 and 192.71 months; p < 0.001, respectively) or HKTx without prior cardiac surgery (203.22 and 203.22 months; p = 0.016 and p = 0.019, respectively), most probably explained by the significantly increased rate of primary nonfunction (33.3%) and in-hospital mortality (25.0%).

CONCLUSIONS

Our data demonstrates the increased rate of early kidney graft loss and thus significantly inferior graft survival in high-risk patients undergoing HKTx. Thus, we advocate for a "kidney-after-heart" program in such patients to ensure responsible and reasonable utilization of scarce resources in times of ongoing organ shortage crisis.

Supportive Hepatocyte Transplantation after Partial Hepatectomy Enhances Liver Regeneration in a Preclinical Pig Model

BACKGROUND

Hepatocyte transplantation (HTx) is regarded as a potential treatment modality for various liver diseases including acute liver failure. We developed a preclinical pig model to evaluate if HTx could safely support recovery from liver function impairment after partial hepatectomy.

METHODS

Pigs underwent partial hepatectomy with reduction of the liver volume by 50% to induce a transient but significant impairment of liver function. Thereafter, 2 protocols for HTx were evaluated and compared to a control group receiving liver resection only (group 1, n = 5). Portal pressure-controlled HTx was performed either immediately after surgery (group 2, n = 6) or 3 days postoperatively (group 3, n = 5). In all cases, liver regeneration was monitored by conventional laboratory tests and the novel noninvasive maximum liver function capacity (LiMAx) test with a follow-up of 4 weeks.

RESULTS

Partial hepatectomy significantly impaired liver function according to conventional liver function tests as well as LiMAx in all groups. A mean of 4.10 ± 1.1 × 108 and 3.82 ± 0.7 × 108 hepatocytes were transplanted in groups 2 and 3, respectively. All animals remained stable with respect to vital parameters during and after HTx. The animals in group 2 showed enhanced liver regeneration as observed by mean postoperative LiMAx values (621.5 vs. 331.3 μg/kg/h on postoperative day 7; p < 0.001) whereas HTx in group 3 led to a significant increase in mean liver-specific coagulation factor VII (112.2 vs. 54.0% on postoperative day 7; p = 0.003) compared to controls (group 1), respectively. In both experimental groups, thrombotic material was observed in the portal veins and pulmonary arteries on histology, despite the absence of clinical symptoms.

CONCLUSION

HTx can be performed safely and effectively immediately after a partial (50%) hepatectomy as well as 3 days postoperatively, with comparable results regarding the enhancement of liver function and regeneration.

[Machine Perfusion for Liver Transplantation - What is Possible and Where Do We Stand in Germany? Review of the Literature and Results of a National Survey]

Machine perfusion of donor livers is currently regarded as the most important innovation in transplant surgery to address the continuing shortage of organs in liver transplantation. Hypothermic machine perfusion (HMP) is safe to use and appears to reduce the risk of biliary complications and improve the long-term survival of transplanted organs following preservation by cold static storage - even in donors after cardiac death. A potential functional test of donor organs during HMP uses flavin mononucleotide and is still under clinical investigation. Normothermic machine perfusion (NMP) has a greater risk of technical problems, but functional testing using conventional laboratory parameters during NMP allows significant expansion of the donor pool, even though no prospective randomised study has been able to demonstrate a survival advantage for transplanted organs after NMP. In addition, the preservation time of the donor organs can be significantly extended with the help of NMP, which is particularly advantageous for complex recipient operations and/or logistics. Both methods could be applied for various scenarios in transplantation medicine - theoretically also in combination. The majority of German transplant centres regard machine perfusion as an important innovation and already actively perform perfusions or are in preparation for doing so. However, the overall practical experience in Germany is still relatively low, with only 2 centres having performed more than 20 perfusions. In the coming years, multi-centre efforts to conduct clinical trials and to develop national guidelines on machine perfusion will therefore be indispensable in order to define the potential of these technological developments objectively and to exploit it optimally for the field of transplantation medicine.

Surgical complications in pediatric kidney transplantation-Incidence, risk factors, and effects on graft survival: A retrospective single-center study

The field of pediatric kidney transplantation remains challenging due to an ongoing lack of size-matched grafts and anatomical peculiarities. In the current study, we investigated the incidence of surgical complications in pediatric recipients, with a focus on risk factors and effects on graft outcome. We retrospectively reviewed all 2386 kidney transplantations at our institution from January 2005 until December 2018. Of these, 221 transplants were performed in pediatric recipients, defined as under the age of 18 years. Donor-recipient body surface area ratios were calculated to evaluate the effects of size mismatching. Regression analyses were performed to identify independent risk factors for surgical complications and graft survival, respectively. Perioperative surgical complications requiring revision were observed in 34 (15.4%) cases. Leading cause for revision were vascular complications such as thrombosis or stenosis (n = 15 [6.8%]), which were significantly more frequent in case of young donors, (ie, donor age <6 years; OR: 4.281; CI-95%:1.385-13.226; P = .012), previous nephrectomy (OR: 3.407; CI-95%:1.019-11.387; P = .046), and en-bloc grafts (OR: 4.923; CI-95%:1.355-17.884; P = .015), followed by postoperative hemorrhage (n = 10 [4.5%]), ureteral complications (n = 8 [3.6%]), and lymphoceles (n = 7 [3.2%]). Median follow-up was 84.13 (0.92-175.72) months. One-, 5-, and 10-year graft survival rates were 97.1%, 88.9%, and 65.1%, respectively. Except for vascular complications (HR: 4.727; CI-95%:1.363-16.394; P = .014), none of the analyzed surgical morbidities significantly influenced graft survival. In conclusion, pediatric kidney transplantation achieves excellent long-term results. However, meticulous surgical technique and continuous postoperative monitoring are imperative for early detection and treatment of imminent vascular complications, especially in case of young donors and en-bloc grafts.

Proposal of a Multivariable Prediction Model for Graded Morbidity after Liver Resection for Colorectal Metastases

BACKGROUND

Prognostic models to predict individual early postoperative morbidity after liver resection for colorectal liver metastases (CLM) are not available but could enable optimized preoperative patient selection and postoperative surveillance for patients at greater risk of complications. The aim of this study was to establish a prognostic model for the prediction of morbidity after liver resection graded according to Dindo.

METHODS

N = 679 cases of primary liver resection for CLM were retrospectively analyzed using univariable and multivariable ordinal regression analyses. Receiver operating characteristics curve (ROC) analysis was utilised to assess the sensitivity and specificity of predictions and their potential usefulness as prognostic models. Internal validation of the score was performed using data derived from 129 patients.

RESULTS

The final multivariable regression model revealed lower preoperative levels, a greater number of units of intraoperatively transfused packed red blood cells (pRBCs), longer duration of surgery, and larger metastases to independently influence postoperatively graded morbidity. ROC curve analysis demonstrated that the multivariable regression model is able to predict each individual grade of postoperative morbidity with high sensitivity and specificity. The areas under the receiver operating curves (AUROC) for all of these predictions of individual grades of morbidity were > 0.700, indicating potential usefulness as a predictive model. Moreover, a consistent concordance in Grades I, II, IV, and V according to the classification proposed by Dindo et al. was observed in the internal validation.

CONCLUSION

This study proposes a prognostic model for the prediction of each grade of postoperative morbidity after liver resection for CLM with high sensitivity and specificity using pre- and intraoperatively available variables.

Multivisceral resection for adenocarcinoma of the pancreatic body and tail-a retrospective single-center analysis

BACKGROUND

Adenocarcinoma of the pancreatic body and tail is associated with a dismal prognosis. As patients frequently present themselves with locally advanced tumors, extended surgery including multivisceral resection is often necessary in order to achieve tumor-free resection margins. The aim of this study was to identify prognostic factors for postoperative morbidity and mortality and to evaluate the influence of multivisceral resections on patient outcome.

METHODS

This is a retrospective analysis of 94 patients undergoing resection of adenocarcinoma located in the pancreatic body and/or tail between April 1995 and December 2016 at our institution. Uni- and multivariable Cox regression analysis was conducted to identify independent prognostic factors for postoperative survival.

RESULTS

Multivisceral resections, including partial resections of the liver, the large and small intestines, the stomach, the left kidney and adrenal gland, and major vessels, were carried out in 47 patients (50.0%). The median postoperative follow-up time was 12.90 (0.16-220.92) months. Median Kaplan-Meier survival after resection was 12.78 months with 1-, 3-, and 5-year survival rates of 53.2%, 15.8%, and 9.0%. Multivariable Cox regression identified coeliac trunk resection (p = 0.027), portal vein resection (p = 0.010), intraoperative blood transfusions (p = 0.005), and lymph node ratio in percentage (p = 0.001) as independent risk factors for survival. Although postoperative complications requiring surgical revision were observed more frequently after multivisceral resections (14.9 versus 2.1%; p = 0.029), postoperative survival was not significantly inferior when compared to patients undergoing standard distal or subtotal pancreatectomy (12.35 versus 13.87 months; p = 0.377).

CONCLUSIONS

Our data indicates that multivisceral resection in cases of locally advanced pancreatic carcinoma of the body and/or tail is justified, as it is not associated with increased mortality and can even facilitate long-term survival, albeit with an increase in postoperative morbidity. Simultaneous resections of major vessels, however, should be considered carefully, as they are associated with inferior survival.

Preoperative leukocytosis and the resection severity index are independent risk factors for survival in patients with intrahepatic cholangiocarcinoma

PURPOSE

The incidence of intrahepatic cholangiocarcinoma is increasing worldwide. Despite advances in surgical and non-surgical treatment, reported outcomes are still poor and surgical resection remains to be the only chance for long-term survival of affected patients. The identification and validation of prognostic factors and scores, such as the recently introduced resection severity index, for postoperative morbidity and mortality are essential to facilitate optimal therapeutic regimens.

METHODS

This is a retrospective analysis of 269 patients undergoing resection of histologically confirmed intrahepatic cholangiocarcinoma between February 1996 and September 2018 at a tertiary referral center for hepatobiliary surgery. Regression analyses were performed to evaluate potential prognostic factors, including the resection severity index.

RESULTS

Median postoperative follow-up time was 22.93 (0.10-234.39) months. Severe postoperative complications (≥ Clavien-Dindo grade III) were observed in 94 (34.9%) patients. The body mass index (p = 0.035), the resection severity index (ASAT in U/l divided by Quick in % multiplied by the extent of liver resection graded in points; p = 0.006), additional hilar bile duct resection (p = 0.005), and number of packed red blood cells transfused during operation (p = 0.036) were independent risk factors for the onset of severe postoperative complications. Median Kaplan-Meier survival after resection was 27.63 months. Preoperative leukocytosis (p = 0.003), the resection severity index (p = 0.005), multivisceral resection (p = 0.001), and T stage ≥ 3 (p = 0.013) were identified as independent risk factors for survival.

CONCLUSION

Preoperative leukocytosis and the resection severity index are useful variables for preoperative risk stratification since they were identified as significant predictors for postoperative morbidity and mortality, respectively.

Abdominal Surgery in Patients with Ventricular Assist Devices: a Single-Center Report

This study was performed to evaluate the incidence and outcome of patients with ventricular assist devices (VADs) undergoing abdominal surgery at our institution. A total of 604 adult patients who underwent VAD implantation between February 2004 and February 2018 were analyzed retrospectively with a median follow-up time of 66 (6-174) months. Thirty-nine patients (6.5%) underwent abdominal surgery. Elective surgical procedures were performed in 22 patients (56.4%), mainly for abdominal wall hernia repairs, partial colectomies, and cholecystectomies. Early after elective abdominal surgery no patient died, resulting in a median survival of 23 (1-78) months. Emergency surgery was performed in 17 patients (43.6%). The most common emergency indications were intestinal ischemia and/or perforation. Eight patients undergoing emergent surgery (44.4%) died within the first 30 days after primary abdominal operation, mainly due to sepsis and consecutive multiple organ failure, resulting in a dismal median survival of one month (0-52). Patients undergoing abdominal surgery had significantly lower rates of realized heart-transplantation (p = 0.031) and a significantly higher rate of VAD exchange, before or after abdominal surgery, due to thromboses or infections (p = 0.037). Nonetheless, overall survival after primary VAD implantation in these patients (median 38 months; 0-107) was not significantly impaired when compared to all other patients undergoing VAD implantation (median 30 months; 0-171). In summary, elective abdominal surgery can be performed safely when well planned by an experienced multidisciplinary team. Abdominal complications in VAD patients requiring emergent surgery, however, lead to a significant increase in short-term morbidity and a high 30-day mortality rate.

An Immunological Model for Heterotopic Heart and Cardiac Muscle Cell Transplantation in Rats

Heterotopic heart transplantation in rats has been a commonly used model for diverse immunological studies for more than 50 years. Several modifications have been reported since the first description in 1964. After 30 years of performing heterotopic heart transplantation in rats, we have developed a simplified surgical approach, which can be easily taught and performed without further surgical training or background. After dissection of the ascending aorta and the pulmonary artery and ligation of superior and inferior caval and pulmonary veins, the donor heart is harvested and subsequently perfused with ice-cold saline solution supplemented with heparin. After clamping and incising the recipient abdominal vessels, the donor ascending aorta and pulmonary artery are anastomosed to the recipient abdominal aorta and inferior vena cava, respectively, using continuous running sutures. Depending on different donor-recipient combinations, this model allows analyses of either acute or chronic rejection of allografts. The immunological significance of this model is further enhanced by a novel approach of in-ear injection of vital cardiac muscle cells and subsequent analysis of draining cervical lymphatic tissue.

Long-term Functional Maintenance of Exteriorized Portal Venous Catheters in a Porcine Animal Model

BACKGROUND

Portal venous access for blood sampling, infusion therapy, and measurement of portal venous pressure is of special interest for experimental studies in surgery, pharmacology, and hepatology. Chronic animal models with continuous portal venous access are rare and especially thrombosis or clotting of permanent catheters is a frequent complication. Aim of this study was to establish a preclinical pig model with a permanent portal venous catheter (PVC).

MATERIALS AND METHODS

PVC implantation was performed in 21 LEWE mini pigs. The catheter was inserted in the distal part of the superior mesenteric vein and fixated with a tobacco-pouch suture. Animals were followed up for 4 wk, directly after implantation of the PVC. Blood gas analyses and portal venous pressures were recorded. Three different groups with continuous infusion via the catheters were defined: NaCl solution (2 mL/h) (group 1), NaCl solution (2 mL/h) + enoxaparin sodium injection (anti-Xa levels of 0.3-0.8 U/mL) (group 2) and heparinized NaCl (2 I.E./mL, 2 mL/h) (group 3).

RESULTS

All 21 PVC implantations were performed without any complications. Application of continuous perfusion with heparinized NaCl (group 3) enabled portal venous access for the entire experiment in 8 of 10 cases (mean of 23.7 d) without any signs of dysfunction. However, for use of NaCl alone or in combination with enoxaparin sodium, catheters were only functional for 6.8 d and 6.9 d, respectively.

CONCLUSIONS

Permanent portal venous access through PVC in mini pigs is achievable by continuous infusion of low-dose heparinized NaCl solution.

Recipient natural killer cells alter the course of rejection of allogeneic heart grafts in rats

Rejection of solid organ grafts is regarded to be dependent on T cell responses. Nonetheless, numerous studies have focused on the contribution of NK cells in this process, resulting in contradictory theories. While some conclude that there is no participation of NK cells, others found an inflammatory or regulative role of NK cells. However, the experimental settings are rarely comparable with regard to challenged species, strain combinations or the nature of the graft. Thus, clear definition of NK cell contribution might be impeded by these circumstances. In this study we performed heterotopic heart transplantation (HTx) in rats, choosing one donor-recipient-combination leading to a fast and a second leading to a prolonged course of graft rejection. We intervened in the rejection process, by depletion of recipient NK cells on the one hand and by injection of activated NK cells syngeneic to the recipients on the other. The fast course of rejection could not be influenced by any of the NK cell manipulative treatments. However, the more prolonged course of rejection was highly susceptible to depletion of NK cells, resulting in significant acceleration of rejection, while injection of NK cells induced acceptance of the grafts. We suggest that, depending on the specific setting, NK cells can attenuate the first trigger of immune response, which allows establishing the regulatory activity leading to tolerance of the graft.

Alloresponses of Mixed Lymphocyte Hepatocyte Culture to Immunosuppressive Drugs as an In-Vitro Model of Hepatocyte Transplantation

Background

Hepatocyte transplantation (HCTx) has the potential for the treatment of end-stage liver disease. However, failure of engraftment and the long-term acceptance of cellular allografts remain significant challenges for its clinical application. The aim of this study was to investigate the efficacy of the immunosuppressive agents, Cyclosporine, Everolimus, and Belatacept to suppress the alloresponse of primary human hepatocytes in a mixed lymphocyte-hepatocyte culture (MLHC) and their potential hepatotoxicity in vitro.

Material/Methods

Primary human hepatocytes were co-cultured with allogeneic peripheral blood mononuclear cells (PBMCs) in an MLHC. Proliferative alloresponses were determined by flow cytometry, and cytokine secretion was measured using Luminex-based multiplex technology. Using an MLHC, the alloresponses of primary human hepatocytes were compared in the presence and absence of Cyclosporine, Everolimus, and Belatacept. Cultured primary human hepatocytes were assessed for the production of albumin, urea, aspartate transaminase (AST) and DNA content. Metabolic activity was determined with the MTT assay.

Results

Immune responses induced by primary human hepatocytes were effectively suppressed by Cyclosporine, Everolimus, and Belatacept. Everolimus significantly reduced the metabolic activity of primary human hepatocytes in vitro, suggesting impairment of cell viability. However, further functional analysis showed no significant differences between treated and untreated controls.

Conclusions

Cyclosporine, Everolimus, and Belatacept suppressed the alloresponse of primary human hepatocytes in an MLHC without significant cytotoxicity or functional cell impairment.

Silencing of HLA class I on primary human hepatocytes as a novel strategy for reduction in alloreactivity

In contrast to the whole liver, primary hepatocytes are highly immunogenic. Thus, alternative strategies of immunomodulation after hepatocyte transplantation are of special interest. Silencing of HLA class I expression is expected to reduce the strength of allogeneic immune responses and to improve graft survival. In this study, primary human hepatocytes (PHH) were isolated using a two-step-collagenase perfusion-technique and co-cultured with allogeneic lymphocytes in terms of a mixed lymphocyte hepatocyte culture. Expression of HLA class I on PHH was silenced using lentiviral vectors encoding for β2-microglobulin-specific short hairpin RNA (shβ2m) or non-specific shRNA (shNS) as control. The delivery of shβ2m into PHH caused a decrease by up to 96% in β2m transcript levels and a down-regulation of HLA class I cell surface expression on PHH by up to 57%. Proliferative T cell alloresponses against HLA-silenced PHH were significantly lower than those observed form fully HLA-expressing PHH. In addition, significantly lower secretion of pro-inflammatory cytokines was observed. Levels of albumin, urea and aspartate-aminotransferase did not differ in supernatants of cultured PHH. In conclusion, silencing HLA class I expression on PHH might represent a promising approach for immunomodulation in the transplant setting without compromising metabolic function of silenced hepatocytes.

Relevant prognostic factors influencing outcome of patients after surgical resection of distal cholangiocarcinoma

Background

Distal cholangiocarcinoma (DCC) is a rare but over the last decade increasing malignancy and is associated with poor prognosis. According to the present knowledge curative surgery is the only chance for long term survival. This study was performed to evaluate prognostic factors for the outcome of patients undergoing curative surgery for distal cholangiocarcinoma.

Methods

75 patients who underwent surgery between January 2000 and December 2014 for DCC in curative intention were analysed retrospectively. Potential prognostic factors for survival were investigated including the extent of surgery using purposeful selection of covariates in multivariable Cox regression modeling.

Results

Preoperative biliary stenting (Hazard ratio (HR): 2.530; 95%-CI: 1.146–6.464, p = 0.020), the extent of surgery in case of positive histological venous invasion (HR: 1.209; 95%-CI: 1.017–1.410, p = 0.032), lymph node staging (HR: 2.183; 95%-CI: 1.250–3.841, p = 0.006), perineural invasion (HR: 2.118; 95%-CI: 1.147–4.054, p = 0.016) and postoperative complications graded in points according to Clavien-Dindo (HR: 1.395; 95%-CI: 1.148–1.699, p = 0.001) were indentified as independent significant risk factors for survival. Patients receiving preoperative biliary stenting showed prolonged duration between onset of symptoms and date of operation (p = 0.048).

Conclusions

Preoperative biliary stenting reduces survival possibly due to delayed surgery. The extent of surgery is not an independent risk factor for survival except for patients with concomitant histological venous invasion. Oncological factors and postoperative surgical complications are independent prognostic factors for survival.

Modified ante situm liver resection without use of cold perfusion nor veno-venous bypass for treatment of hepatic lesions infiltrating the hepatocaval confluence

PURPOSE

Treatment of malignancies invading the hepatic veins/inferior vena cava is a surgical challenge. An ante situm technique allows luxation of the liver in front of the situs to perform tumor resection. Usually, cold perfusion and veno-venous bypass are applied. Our experience with modified ante situm resection relying only on total vascular occlusion is reported.

METHODS

Retrospective analysis on an almost 15-year experience with ante situm resection without application of cold perfusion or veno-venous bypass RESULTS: The ante situm technique was applied on eight patients. Five individuals were treated due to intrahepatic cholangiocellular cancer and one case each for mixed cholangio-/hepatocellular carcinoma, colorectal liver metastasis, and pheochromocytoma. Trisectorectomy (n = 4), left hemihepatectomy, right hepatectomy, atypical resection, or mesohepatectomy (each n = 1) were performed, combined with dissection of suprahepatic/retrohepatic vena cava/hepatic veins. Venous reconstruction was achieved by reimplantation of hepatic veins with/without vascular replacement using allogeneic donor veins or PTFE grafts. Median total vascular occlusion of the liver was 23 min. Severe morbidity occurred in three patients (Dindo-Clavien > 3A). R0 status was achieved in six cases with a median overall survival of 33.5 months.

CONCLUSIONS

Ante situm liver resection can be applied without cold perfusion nor veno-venous bypass with acceptable morbidity and mortality. However, this procedure remains challenging even for the experienced hepato-pancreato-biliary surgeon.

Identification of the resection severity index as a significant independent prognostic factor for early mortality and observed survival >5 and >10 years after liver resection for hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

This study evaluates predictive factors for observed long-term survival of more than 5 and 10 years for patients after liver resection for hepatocellular carcinoma and compares their life expectancy to the normal national population matched for sex, year of birth and age at resection.

METHODS

230 patients after primary liver resection for HCC (01.01.1995-31.12.2004) were analyzed. Multivariable logistic regression models were determined based on Cox regression results and their prognostic capability evaluated with areas under the receiver operating characteristic curve (AUROCs).

RESULTS

Life years after surgery in deceased patients compared to the normal national population matched for sex, year of birth and age at resection was reduced by median 21.7 years. Independent predictive factors for 10-year survival were age at resection (p < 0.001; OR = 0.898; 95%-CI: 0.846-0.954), UICC 7 tumor staging (p = 0.003; OR = 0.344; 95%-CI: 0.126-0.941) and ASAT (GOT) in U/l divided by Quick in percent multiplied by the extent of liver resection graded in points labelled as the resection severity index (p < 0.001; OR = 0.136; 95%-CI: 0.022-0.843) enabling prediction of 10-year survival with an AUROC of 0.884. The same factors plus revision surgery (yes/no) predict 5-year survival (AUROC 0.736).

CONCLUSIONS

Liver resection enables predictable long-term survival >5 and > 10 years. The proposed resection severity index quantifies the prognostic relevance of liver cellular damage, synthesis and loss of parenchyma for long-term survival.

Memory-updating abrogates extinction of learned immunosuppression

When memories are recalled, they enter a transient labile phase in which they can be impaired or enhanced followed by a new stabilization process termed reconsolidation. It is unknown, however, whether reconsolidation is restricted to neurocognitive processes such as fear memories or can be extended to peripheral physiological functions as well. Here, we show in a paradigm of behaviorally conditioned taste aversion in rats memory-updating in learned immunosuppression. The administration of sub-therapeutic doses of the immunosuppressant cyclosporin A together with the conditioned stimulus (CS/saccharin) during retrieval blocked extinction of conditioned taste aversion and learned suppression of T cell cytokine (interleukin-2; interferon-γ) production. This conditioned immunosuppression is of clinical relevance since it significantly prolonged the survival time of heterotopically transplanted heart allografts in rats. Collectively, these findings demonstrate that memories can be updated on both neural and behavioral levels as well as on the level of peripheral physiological systems such as immune functioning.

Evaluation of a systemic antibiotic treatment of toxic puerperal metritis in dairy cows

The objective of this study was to evaluate the efficacy and economic efficiency of a systemic treatment of toxic puerperal metritis in dairy cows with ceftiofur. Cows with abnormal vaginal discharge at a postpartum examination (d 4 to 6 after calving) and a rectal temperature > or = 39.5 degrees C were assigned to three treatment groups. Cows in group 1 (n = 70) received 600 mg of ceftiofur intramuscularly (i.m.) on 3 consecutive days. Cows in group 2 (n = 79) received an intrauterine treatment with antibiotic pills consisting of 2500 mg of ampicillin and 2500 mg of cloxacillin and an additional 6000 mg (i.m.) of ampicillin. This treatment was performed on 3 consecutive days. Cows in group 3 (n = 78) received the same intrauterine treatment as in group 2. In addition, 600 mg of ceftiofur was administered i.m. on 3 consecutive days. Body temperature was recorded daily for 6 d after first treatment. There were no significant differences among the groups regarding clinical efficacy at d 6 after first treatment. The cure rates based on rectal temperatures declining to below 39.5 degrees C on d 6 after treatment were 82.9, 84.8, and 84.6% for groups 1, 2, and 3, respectively. Reproductive performance did not differ significantly between group 1 and groups 2 and 3 for any of the measures tested. A financial analysis with 87 different cost scenarios demonstrated that a systemic treatment of toxic puerperal metritis in cattle with ceftiofur is an effective alternative to the combination of local and systemic treatments.