Assessment of Surgeons' Stress Levels with Digital Sensors during Robot-Assisted Surgery: An Experimental Study.

Robot-Assisted Minimally Invasive Surgery (RAMIS) marks a paradigm shift in surgical procedures, enhancing precision and ergonomics. Concurrently it introduces complex stress dynamics and ergonomic challenges regarding the human-robot interface and interaction. This study explores the stress-related aspects of RAMIS, using the da Vinci XI Surgical System and the Sea Spikes model as a standard skill training phantom to establish a link between technological advancement and human factors in RAMIS environments. By employing different physiological and kinematic sensors for heart rate variability, hand movement tracking, and posture analysis, this research aims to develop a framework for quantifying the stress and ergonomic loads applied to surgeons. Preliminary findings reveal significant correlations between stress levels and several of the skill-related metrics measured by external sensors or the SURG-TLX questionnaire. Furthermore, early analysis of this preliminary dataset suggests the potential benefits of applying machine learning for surgeon skill classification and stress analysis. This paper presents the initial findings, identified correlations, and the lessons learned from the clinical setup, aiming to lay down the cornerstones for wider studies in the fields of clinical situation awareness and attention computing.

Systematic Review on Characteristics and Reporting Quality of Animal Studies in Liver Regeneration Triggered by Portal Vein Occlusion and Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy: Adherence to the ARRIVE Guidelines.

BACKGROUND: Portal vein occlusion and associating liver partition and portal vein ligation for staged hepatectomy techniques are in the spotlight of oncological liver surgery. Research involving animal models is indispensable to study the mechanisms of liver regeneration. Inaccurate reporting acts as a significant barrier during the correct interpretation of preclinical findings. Hence, we performed a systematic review to evaluate the status quo of the reporting standards and to assess the potential factors influencing reporting in animal studies, which are focusing on portal vein occlusion and/or associating liver partition and portal vein ligation for staged hepatectomy techniques. MATERIALS AND METHODS: A systematic review was performed in the PubMed and Ovid MEDLINE databases. Baseline study characteristics were recorded, and quality assessment was performed using the Animals in Research: Reporting in vivo Experiments (ARRIVE) checklist. RESULTS: A total of 107 research articles were included for the comprehensive assessment. In the subgroup analysis, newer reports and studies from the post-ARRIVE era, and reports from Europe were all associated with significantly higher ARRIVE scores (P < 0.05). Univariable regression analysis confirmed these factors as predictors of higher reporting quality. However, in the multivariable analysis, only publishing in the post-ARRIVE era has been found as single independent predictor of higher reporting standards (P = 0.028 post-ARRIVE total score 75th percentile; P = 0.000 post-ARRIVE total score median). CONCLUSIONS: Although an improving trend has been observed in reporting quality over the past years, this effect was clearly insufficient. Our results emphasize the need for further measures to improve the methodical quality at all levels of planning, execution, and reporting of preclinical studies in liver regeneration research.

A novel percutaneous transhepatic treatment of a benign bile duct stricture - a pilot study.

AIM: To assess the effectiveness and outcome of repeated percutaneous transhepatic balloon dilatation combined with targeted intramucosal corticosteroid injection in patients with benign biliary stricture. METHODS: This single-center pilot study, conducted between February 2014 and June 2016, involved five patients with benign biliary stricture (4 men and 1 woman, mean age 58.2 years). The study included only patients in whom previous surgical or/and non-surgical treatments failed or could not be performed due to patients' medical history and local status. RESULTS: We successfully developed an alternative treatment for patients with benign biliary stricture and performed it without side effects. There were no major complications, and the only one minor complication was cholangitis. In the median follow-up period of 30.24 months (range 14.5 to 44.6 months), no re-occlusion was detected. The disease-free survival, calculated after excluding the first patient (who died of heart attack), was 34.175 months. CONCLUSION: Percutaneous transhepatic corticosteroid injection combined with balloon dilatation could provide an alternative method for the treatment of benign biliary strictures that is effective in the long term and results in positive outcomes.

Isoform-Dependent Changes in Cytochrome P450-Mediated Drug Metabolism after Portal Vein Ligation in the Rat.

BACKGROUND: Surgical removal of complicated liver tumors may be realized in two stages via selective portal vein ligation, inducing the atrophy of portally ligated lobes and the compensatory hypertrophy of nonligated liver lobes. Unlike morphological changes, functional aspects such as hepatic cytochrome P450 (CYP)-mediated drug metabolism remain vaguely understood, despite its critical role in both drug biotransformation and hepatic functional analysis. Our goal was the multilevel characterization of hepatic CYP-mediated drug metabolism after portal vein ligation in the rat. METHODS: Male Wistar rats (n = 24, 210-230 g) were analyzed either untreated (controls; n = 4) or 24/48/72/168/336 h (n = 4 each) following portal vein ligation affecting approximately 80% of the liver parenchyma. Besides the weights of ligated and nonligated lobes, pentobarbital (30 mg/kg)-induced sleeping time, CYP1A(2), CYP 2B(1/2), CYP2C(6/11/13), CYP3A(1) enzyme activities, and corresponding isoform mRNA expressions, as well as CYP3A1 protein expression were determined by in vivo sleeping test, CYP isoform-selective assays, polymerase chain reaction, and immunohistochemistry, respectively. RESULTS: Portal vein ligation triggered atrophy in ligated lobes and hypertrophy nonligated lobes. Sleeping time was transiently elevated (p = 0.0451). After an initial rise, CYP1A, CYP2B, and CYP3A enzyme activities dropped until 72 h, followed by a potent increase only in the nonligated lobes, paralleled by an early (24-48 h) transcriptional activation only in nonligated lobes. CYP2C enzyme activities and mRNA levels were bilaterally rapidly decreased, showing a late reconvergence only in nonligated lobes. CYP3A1 immunohistochemistry indicated substantial differences in positivity in the early period. CONCLUSIONS: Beyond the atrophy-hypertrophy complex, portal vein ligation generated a transient suppression of global and regional drug metabolism, re-established by an adaptive, CYP isoform-dependent transcriptional response of the nonligated lobes.

[Surgical treatment of primary liver malignancies]. / A máj primer rosszindulatú daganatainak sebészeti kezelése.

The incidence of primary malignant liver tumours is globally rising. Hepatocellular carcinoma constitutes 75-85% of primary liver malignancies. Owing to advancements of oncological therapies, several methods are available to combat the tumour. Upon the complexity of the disease and the wide spectrum of therapeutical regimens, therapy of HCC is debated, with several undecided issues. Noteworthy, however, is that in early tumour stages, as a de facto curative approach, surgical therapy remains the most effective, allowing long-term survival. Intrahepatic cholangiocellular carcinoma (iCCC) is the second most frequent primary malignant liver tumour. Despite technical developments, prognosis of iCCC patients remains dismal. Unfortunately, as the sole curative approach, surgery (nearing 40% 5-year survival) is mostly contraindicated because of a late diagnosis. In these cases, median survival remains below 7-12 months despite parallel palliative therapies. The present review focuses on the surgical management of primary malignant liver tumours.

Sensitivity of Helicobacter pylori detection by Giemsa staining is poor in comparison with immunohistochemistry and fluorescent in situ hybridization and strongly depends on inflammatory activity.

BACKGROUND: Conventional stainings (including H&E and special stains like Giemsa) are the most widely applied histopathologic detection methods of Helicobacter pylori (HP). MATERIALS AND METHODS: We aimed to compare the diagnostic performance of Giemsa staining with immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) on a monocentric cohort of 2896 gastric biopsies and relate results to histologic alterations in order to find such histopathologic subgroups in which these methods underperform. All cases were categorized regarding presence or absence of chronic gastritis, inflammatory activity, and mucosal structural alterations. RESULTS: Giemsa revealed 687 cases (23.7%), IHC 795 cases (27.5%), and FISH 788 cases (27.2%) as being HP positive. Giemsa showed significantly lower overall sensitivity (83.3%) compared to IHC (98.8%) and FISH (98.0%). Moreover, the sensitivity of Giemsa dramatically dropped to 33.6% in the nonactive cases. We found that sensitivity of Giemsa strongly depends on HP density and, accordingly, on the presence of activity. Structural alterations (intestinal metaplasia, atrophy, etc.) had only no or weak effect on sensitivity of the three stainings. Both IHC and FISH proved to be equally reliable HP detecting techniques whose diagnostic performance is minimally influenced by mucosal inflammatory and structural alterations contrary to conventional stainings. CONCLUSIONS: We highly recommend immunohistochemistry for clinically susceptible, nonactive chronic gastritis cases, if the conventional stain-based HP detection is negative. Moreover, we recommend to use IHC more widely as basic HP stain. Helicobacter pylori FISH technique is primarily recommended to determine bacterial clarithromycin resistance. Furthermore, it is another accurate diagnostic tool for HP.

Animal Models for Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS): Achievements and Future Perspectives.

BACKGROUND: Since 2012, Associated Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS) has been standing in the limelight of modern liver surgery and numerous questions have been raised regarding this novel approach. On the one hand, ALPPS has proved to be a valuable method in the treatment of hepatic tumors, while on the other hand, there are many controversies, such as high mortality and morbidity rates. Further surgical research is essential for a better understanding of underlying mechanisms and for enhancing patient safety. SUMMARY: Until recently, only 8 animal models have been created with the purpose to mimic ALPPS-induced liver regeneration. From these 7 are rodent (6 rat and 1 mouse) models, while only 1 is a large animal model, which uses pigs. In case of rodent models, portal flow deprivation of 75-90% is achieved via portal vein ligation leaving only the right (20-25%) or left median (10-15%) lobes portally perfused, while liver splitting in general is carried out positioned according to the falciform ligament. As for the swine model, the left lateral and medial lobes (70-75% of total liver volume) are portally ligated, and the right lateral lobe (accounting for 20-24% of the parenchyma) is partially resected in order to reach critical liver volume. Each model is capable of reproducing the accelerated liver regeneration seen in human cases. However, all species have significantly different liver anatomy compared with the human anatomic situation, making clinical translation somewhat difficult. Key Messages: Unfortunately, there are no perfect animal models available for ALPPS research. Small animal models are inexpensive and well suited for basic research, but may only provide limited translational potential to humans. Clinically large animal models may provide more relevant data, but currently no suitable one exists.

Liver regeneration after different degrees of portal vein ligation.

BACKGROUND: Selective portal vein ligation (PVL) is followed by ipsilateral atrophy and contralateral hypertrophy of the liver lobes. Although the atrophy-hypertrophy complex induced by PVL is a well-documented phenomenon, the effect of different degrees of extended portal vein occlusion on liver regeneration is not known. The aim of this study was to assess the effects of different degrees of portal occlusion on portal pressure and liver regeneration. MATERIALS AND METHODS: Male Wistar rats (n = 96; 220-250 g) were randomized into three groups and underwent 70%, 80%, or 90% portal vein ligation, respectively. The portal pressure was measured immediately and 24, 48, 72, 120, and 168 h after PVL (n = 6/group/time point). The hepatic lobes and the spleen were weighed, and liver regeneration ratio was calculated. Changes in liver histology and the mitotic activity were assessed on hematoxylin-eosin stained slides. RESULTS: Higher degree of portal occlusion triggered a stronger regenerative response (regeneration ratio of PVL 70%168h = 2.23 ± 0.13, PVL 80%168h = 3.11 ± 0.37, PVL 90%168h = 4.68 ± 0.48) PVL led to an immediate increase in portal pressure, the value of which changed proportionally to the mass of liver tissue deprived of portal perfusion (PVL 70%acute = 17 ± 2 mm Hg, PVL 80%acute = 19 ± 1 mm Hg, PVL 90%acute = 26 ± 4 mm Hg). Findings in histology showed necro-apoptotic lesions in the atrophic liver lobes and increased mitotic cell count in the hypertrophic lobes. The mitotic cell count of PVL 90% peaked earlier and at a significantly higher value than of PVL 70% and PVL 80% (PVL 9024h%: 96.0 ± 3.5 PVL 70%48h: 64.0 ± 2.1, PVL 80%48h: 56.3 ± 4.0). The mitotic index after 24 h showed a strong correlation with the acute portal hypertension. CONCLUSIONS: A higher degree of portal vein occlusion leads to a greater regenerative response, presumably triggered by the proportional increase in portal pressure, which supports the role of the so-called "blood-flow" theory of PVL-triggered liver regeneration.

Postconditioning in major vascular surgery: prevention of renal failure.

BACKGROUND: Postconditioning is a novel reperfusion technique to reduce ischemia-reperfusion injuries. The aim of the study was to investigate this method in an animal model of lower limb revascularization for purpose of preventing postoperative renal failure. METHODS: Bilateral lower limb ischemia was induced in male Wistar rats for 3 hours by infrarenal aorta clamping under narcosis. Revascularization was allowed by declamping the aorta. Postconditioning (additional 10 sec reocclusion, 10 sec reperfusion in 6 cycles) was induced at the onset of revascularization. Myocyte injury and renal function changes were assessed 4, 24 and 72 hours postoperatively. Hemodynamic monitoring was performed by invasive arterial blood pressure registering and a kidney surface laser Doppler flowmeter. RESULTS: Muscle viability studies showed no significant improvement with the use of postconditioning in terms of ischemic rhabdomyolysis (4 h: ischemia-reperfusion (IR) group: 42.93 ± 19.20% vs. postconditioned (PostC) group: 43.27 ± 27.13%). At the same time, renal functional laboratory tests and kidney myoglobin immunohistochemistry demonstrated significantly less expressed kidney injury in postconditioned animals (renal failure index: 4 h: IR: 2.37 ± 1.43 mM vs. PostC: 0.92 ± 0.32 mM; 24 h: IR: 1.53 ± 0.45 mM vs. PostC: 0.77 ± 0.34 mM; 72 h: IR: 1.51 ± 0.36 mM vs. PostC: 0.43 ± 0.28 mM), while systemic hemodynamics and kidney microcirculation significantly improved (calculated reperfusion area: IR: 82.31 ± 12.23% vs. PostC: 99.01 ± 2.76%), and arterial blood gas analysis showed a lesser extent systemic acidic load after revascularization (a defined relative base excess parameter: 1(st) s: IR: 2.25 ± 1.14 vs. PostC: 1.80 ± 0.66; 2(nd) s: IR: 2.14 ± 1.44 vs. PostC: 2.44 ± 1.14, 3(rd) s: IR: 3.99 ± 3.09 vs. PostC: 2.07 ± 0.82; 4(th) s: IR: 3.28 ± 0.32 vs. PostC: 2.05 ± 0.56). CONCLUSIONS: The results suggest a protective role for postconditioning in major vascular surgeries against renal complications through a possible alternative release of nephrotoxic agents and exerting a positive effect on hemodynamic stability.

Improvement of small intestinal microcirculation by postconditioning after lower limb ischemia.

BACKGROUND: Major lower limb vascular surgeries may result in severe, remote injury of the gastrointestinal system, which has high mortality rates. Postconditioning is a technique with potential capability of reducing remote gastrointestinal complications. Our aim was to assess the remote macro- and micro-hemodynamic changes of the small intestine following an infrarenal aortic occlusion and to evaluate the effects of postconditioning on these alterations. METHODS: Rats underwent 3h of infrarenal aortic occlusion followed by 4h of reperfusion. In one group, postconditioning was applied. Blood pressure, superior mesenteric artery flow and mucosal microcirculation of the duodenum, jejunum and ileum were assessed. Samples were taken from each intestinal segment for histological examinations. RESULTS: Superior mesenteric artery flow, as well as microcirculation of the duodenum, jejunum and ileum showed significant impairment in the IR group, while histological damage was significantly worsened. Postconditioning was able to limit flow reduction in all three small bowel segments and in the superior mesenteric artery, and was able to significantly reduce histological damage. Strong negative correlation was found between microcirculatory values and histological damage. CONCLUSIONS: Microcirculatory impairment might be responsible for remote intestinal injury following infrarenal aortic occlusion. Postconditioning was able to reduce this remote intestinal damage.

Neural elements behind the hepatoprotection of remote perconditioning.

BACKGROUND: The ability of remote ischemic perconditioning (RIPER) to protect the liver from ischemic-reperfusion (IR) injury has been reported before; however, the mechanism behind the positive effects of RIPER remains unrevealed. Therefore, we aimed to investigate the potential role of neural elements to transfer protective signals evoked by perconditioning. MATERIALS AND METHODS: Male Wistar rats were randomly allocated into six groups (sham, IR, RIPER ± denervation; n = 7 per group). Half of the animals underwent left femoral and sciatic nerve resection. In IR and RIPER groups, normothermic, partial (70%) liver ischemia lasting for 60 min was induced; parallel animals in the RIPER groups received perconditioning treatment (4 × 5 - 5 min IR, left femoral artery clamping). Hepatic microcirculation and systemic blood pressure were monitored during the first postischemic hour. After 24 h of reperfusion, liver samples were taken for histology and redox-state analysis. Automated image analysis software was used for necrosis quantification. Serum alanine aminotransferase, aspartate aminotransferase, and bilirubin levels were measured. RESULTS: Microcirculation and blood pressure showed significant improvement during reperfusion after perconditioning. This phenomenon was completely abolished by nerve resection (P < 0.05; RIPER versus IR, IR + denervation, and RIPER + denervation). Results of necrosis quantification showed similar pattern. Besides noncharacteristic changes in aspartate aminotransferase levels, alanine aminotransferase values were significantly lower (P < 0.05) in the RIPER group compared with the other IR groups. Mild but significant alterations were observed in liver function assessed by total bilirubin levels. Further supporting results were obtained from analysis of redox homeostasis. CONCLUSIONS: Perconditioning was able to reduce liver IR injury in our model via a mechanism most probably involving interorgan neural pathways.

Alterations in hepatic lobar function in regenerating rat liver.

BACKGROUND: Ligation of a branch of the portal vein redirects portal blood to nonligated lobes resulting in lobar hypertrophy. Although the effect of portal vein ligation on liver volume is well documented, the parallel alterations in liver function are still the subject of controversy. Our aim was to assess the time-dependent reactions of regional hepatic function to portal vein ligation by selective biliary drainage. METHODS: Male Wistar rats (n = 44) underwent 80% portal vein ligation. Before the operation as well as 1, 2, 3, 5, and 7 d after circulation, morphology and function (laboratory blood test; hepatic bile flow; plasma disappearance rate of indocyanine green; and biliary indocyanine green excretion) of the liver were examined. RESULTS: Although portal vein ligation affected liver circulation and morphology to a great extent, serum albumin levels, bilirubin levels, and total hepatic bile flow did not change significantly after the operation. Nevertheless, plasma disappearance rate and biliary indocyanine green excretion indicated a temporary impairment of total liver function with the lowest value on the second day and normalization by the fifth day. Bile production and biliary indocyanine green excretion of ligated lobes decreased rapidly after the operation and remained persistently suppressed, whereas the secretory function of nonligated lobes--after a temporary decline--showed a greater increase than the weight of the lobes. CONCLUSIONS: Portal vein ligation induced temporary impairment of total liver function, followed by rapid recovery mainly by reason of increase in the function of nonligated lobes. Functional increase in nonligated lobes was more pronounced than suggested by the degree of volume gain.

Triggered liver regeneration: from experimental model to clinical implications.

BACKGROUND: Major liver resection is the only therapeutic option for patients with malignant liver tumors. However, extended hepatectomy often leads to postoperative liver failure, mainly due to insufficient amounts of the remnant liver. Recently, selective portal vein occlusion (PVO) has been introduced to increase the remnant liver volume. This novel surgical technique initiated a progressive development in liver surgery, resulting in a significant increment in potential candidates for curative liver resection. SUMMARY: The theoretical basis for this great advancement is formed by an understanding of the mechanisms of PVO-induced liver regeneration, mainly obtained from animal studies. The aim of this review is to give a comprehensive overview of the relevant animal models of PVO and to discuss the main characteristics of triggered liver regeneration, including the induced hemodynamic, morphological and functional alterations as well as the underlying molecular mechanisms, which might be of interest in both the laboratory and the clinic. Key Messages: Although basic research revealed the main characteristics of PVO-triggered liver regeneration within the last decades, several important issues regarding the regenerative process remain uncertain. To answer these open questions, additional well-designed animal experiments are needed in the future, which allow further refinement of this surgical technique.

Improving Research Practice in Rat Orthotopic and Partial Orthotopic Liver Transplantation: A Review, Recommendation, and Publication Guide.

BACKGROUND: Due to a worldwide shortage of donor organs for liver transplantation, alternative approaches, such as split and living donor liver transplantations, were introduced to increase the donor pool and reduce mortality on liver transplant waiting lists. Numerous details concerning the mechanisms and pathophysiology of liver regeneration, small-for-size syndrome, rejection, and tolerance in partial liver transplantation facilitated the development of various animal models. The high number of preclinical animal studies contributed enormously to our understanding of many clinical aspects of living donor and partial liver transplantations. SUMMARY: Microsurgical rat models of partial orthotopic liver transplantation are well established and widely used. Nevertheless, several issues regarding this procedure are controversial, not clarified, or not yet properly standardized (graft rearterialization, size reduction techniques, etc.). The major aim of this literature review is to give the reader a current overview of rat orthotopic liver transplantation models with a special focus on partial liver transplantation. The aspects of model evolution, microsurgical training, and different technical problems are analyzed and discussed in detail. Our further aim in this paper is to elaborate a detailed publication guide in order to improve the quality of reporting in the field of rat liver transplantation according to the ARRIVE guidelines and the 3R principle. Key Messages: Partial orthotopic liver transplantation in rats is an indispensable, reliable, and cost-efficient model for transplantation research. A certain consensus on different technical issues and a significant improvement in scientific reporting are essential to improve transparency and comparability in this field as well as to foster refinement.

New method for treatment of inferior vena cava tumor thrombus ­ case study.

Conventional surgical therapy for advanced renal venous tumor thrombi results in high morbidity, so there is a need for less invasive techniques. This report presents the first case of a successful inferior vena cava (IVC) tumor thrombus removal without complications with balloon catheter (BC) via internal jugular vein (IJV), called the venous tumor thrombus pushing with balloon catheter (VTTP BC). Under the control of transesophageal echocardiogram and fluoroscope, a balloon catheter was sleeved on the guide wire, which was already inserted into the right internal jugular vein (IJV) and was driven distally above the IVC tumor thrombus. The balloon was inflated to occlude the IVC for prevention of pulmonary embolization. After the occlusion, the guide wire was driven to the cavotomy and was opened at the ostium of the right renal vein. It was pulled at both ends and stretched to serve as a rail. The balloon was gently pushed toward the cavotomy and the thrombectomy was completed. This is a less invasive method for treatment of venous tumor thrombus level 3 that can reduce surgical time, blood loss, and complication rates compared to the existing surgical methods. Also, it can be performed without thoracotomy, cardiopulmonary bypass, hypothermic circulatory arrest, and liver mobilization.

[Free radicals and hepatic ischemia-reperfusion]. / Szabad gyökök és a máj ischaemiás-reperfúziós károsodása.

The critical importance of the ischemic-reperfusive injury is well documented with regards to numerous organs and clinical conditions. Oxygen free radicals play a central role in the mediation of the injury, which dominantly influences the prevalence of postoperative complications, (long term) organ damage, and the potential manifestation of systemic reactions. The both anatomically and pathophysiologically unique ischemic-reperfusive injury of the liver, which is expressively vulnerable to free radicals, is of utmost importance in liver surgery. Several techniques (adaptive maneuvers, chemical agents) are known to ameliorate the reperfusive injury. Based on the prior research of the workgroup of the author, the aim of the current article is to overview the set of measures capable of attenuating ischemic-reperfusive injury (ischemic preconditioning, -perconditioning, administration of adenosine, -inosine, -levosimendan, and -poly-ADP-ribose-polymerase inhibitor), with special attention to the ischemic-reperfusive injury of the liver, as well as the special pathophysiological role of free radicals in mediating hepatic damage.

[The importance of postoperative circulatory alterations in hepatic surgery]. / A posztoperatív keringésváltozások jelentosége a májsebészetben.

There are two afferent (hepatic artery, portal vein) and one efferent (hepatic veins) systems responsible for the unique circulation of the liver. Given this special form of vasculature, acute, isolated (i.e. involving selectively one particular vessel) vascular occlusions may lead to different, however still life threatening conditions. Hence, it is essential to recognize these anomalies in order to preserve the healthy state of both the liver and the patient's lives. Acute circulatory failures are dominantly associated with liver surgery. Adequate therapy can only be provided promptly, if the clinician is well aware of the peculiarities of these conditions. The aim of this study is to overview the etiology and symptoms of these clinical conditions; furthermore to offer technical proposals for the required diagnostic and therapeutical steps via case reports. Furthermore, hepatic injury, caused by ischemia-reperfusion secondary to total vascular occlusion (Pringle maneuver) used in hepatic surgery is outlined.

[Laparoscopic surgery of benign liver tumours]. / Benignus májdaganatok laparoszkópos resectiója.

273 patients underwent elective surgical treatment for benign liver lesions at the 1st Surgical Department of Semmelweis University, Budapest, Hungary between 2004 and 2014. Laparoscopic (LAP) interventions were performed in 83 cases. Cyst fenestration in 52, and hepatic resection in 31 cases. LAP liver resections were set against to open surgery of paired group of patients with comparable demographic and clinical parameters. Data revealed that the operative time in LAP group (113.7 min) was significantly longer than that in the open surgery group (89.5 min). The average postoperative length of hospital stay was shorter after LAP surgery (5.8 vs 9.1 days). There was no postoperative complication in the LAP group, two wound infections and one biliary collection were treated by ultrasonic drainage in the open group. Three patients were given blood transfusion in the LAP, four in the open group. Operative mortality was zero, and no reoperation required. The surgical technique which is described in detail in the text enables safe resection of segments 7-8 which are difficult to approach. Our data support the safety and feasibility of laparoscopic liver resection after adequate preoperative investigations.

Postconditioning of the small intestine: which is the most effective algorithm in a rat model?

BACKGROUND: Mesenteric ischemia is a serious clinical condition requiring immediate surgical intervention. The unavoidable ischemic-reperfusion (IR) injury may be ameliorated using the appropriate postconditioning protocol. The aim of the present study was to investigate the optimal postconditioning algorithm in a rat model of intestinal ischemic-reperfusion injury. MATERIALS AND METHODS: Male Wistar rats were randomized into five groups (n = 10), one sham-operated, one IR, and three postconditioned groups, each with different protocols. The animals were subjected to 60 min of mesenteric ischemia, followed by 60 min of reperfusion. Postconditioning was applied at the onset of reperfusion using three different algorithms. Arterial pressure and mucosal microcirculation were monitored throughout the experiment. Mesenteric pH was determined at the early phase of reperfusion. Blood and tissue samples were taken at the end of reperfusion for histologic evaluation, serum lactate dehydrogenase, serum creatine kinase, serum tumor necrosis factor-α, serum interleukin-6, detailed mucosal antioxidant, and scavenger capacity assays. RESULTS: The shorter and intermediate length cycles of postconditioning enhanced mucosal microcirculation and redox state and significantly delayed the normalization of mesenteric pH. Furthermore, milder histopathologic lesions and lower concentrations of serum necroenzymes and proinflammatory cytokines were detected compared with the IR group. The protective effect of postconditioning using longer cycles could only be seen in a tendentious manner. CONCLUSIONS: In a rat model of intestinal ischemia-reperfusion, the shorter and intermediate length cycles of postconditioning proved to be more effective than the use of longer cycles.

Collateral circulation of the rat lower limb and its significance in ischemia-reperfusion studies.

PURPOSE: Rats are the most commonly used animal model for studies of acute lower limb ischemia-reperfusion. The ischemia induced by arterial clamping may cause milder damage than the application of a tourniquet if the presence of a possible collateral system is considered. METHODS: Male Wistar rats were randomized into three groups: in group A, the muscle weight affected by ischemia was measured; in group B, the severity of muscle damage caused by the application of a tourniquet and by infrarenal aortic occlusion was examined. Blood and muscle samples were taken from group B to assess the serum necroenzyme, potassium and TNF-α levels, as well as the muscle fiber viability and for histological examinations. In group C, the identification of the lower limb collateral system was performed using corrosion casting. RESULTS: Tourniquet application affected the lower muscle mass and resulted in significantly more severe injury compared to infrarenal aortic occlusion. This difference was reflected in the serum necroenzyme, potassium and TNF-α levels. The histological examination and viability assay confirmed these findings. The corrosion casts showed several anastomoses capable of supplying the lower limb. CONCLUSION: Tourniquet application proved to be capable of inducing absolute lower limb ischemia, in contrast to infrarenal aortic ligation, where a rich collateral system is considered to help mitigate the injury.