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Objective Posterior fossa or midline tumors are often associated with hydrocephalus and primary tumor removal with or without perioperative placement of an external ventricular drain (EVD) is commonly accepted as first-line treatment. Shunting prior to posterior fossa surgery (PFS) is mostly reserved for symptomatic cases or special circumstances. There are limited data regarding the anticipated risk for symptomatic pneumocephalus and the perioperative management using the semi-sitting position (SSP) in such a scenario. Here, we therefore assessed the safety of performing PFS in a consecutive series of patients over a period of 15 years to allow the elaboration of recommendations for perioperative management. Methods According to specific inclusion and exclusion criteria a total of 13 patients who underwent 17 operations was identified. Supratentorial pneumocephalus was evaluated with semiautomatic-volumetric segmentation. The volume of pneumocephalus was evaluated according to age and ventricular size. Results Ten of the 13 patients had a programmable valve (preoperative valve setting range 6–14 cmH20; mean 7.5 cmH20) while 3 patients had non programmable valves. A variable amount of supratentorial air collection was evident in all patients postoperatively (range 3.2–331 ml; mean 122.32 ml). Positive predictors for the volume of postoperative pneumocephalus were higher age and a preoperative Evans ratio > 0.3. In our series, we encountered no cases of tension pneumocephalus necessitating an air replacement procedure as well as no obstruction, disconnection, infection or hardware malfunction of the shunt system. Conclusions Our findings indicate that a CSF shunt in situ is not a contraindication for performing PFS in the semi-sitting position and it does not increase the pre-existing risk for postoperative tension pneumocephalus. In cases of primary shunting for hydrocephalus associated with posterior fossa tumors a programmable valve set at a medium opening pressure with a gravitational device is a valid option when PFS in the semi-sitting position is opted. In patients with an indwelling shunt diversion system special caution is indicated in order to prevent and detect overdrainage especially in not adjustable valves or shunts without antisiphon devices.

This paper proposes an adaptive attitude stabilization approach for flexible spacecraft subject to uncertainties, external disturbances, actuator saturation and unknown dynamics. The approach is synthesized based on a modified nonsingular fast terminal sliding surface (NFFTSS) and ensures fast and finite-time convergence independently of the initial states. It employs time-varying gains into the sliding manifolds and the control scheme to yield improved convergence speed over fixed-time based approaches. The upper bounds of the uncertainties are estimated using an adaptive mechanism in which no prior knowledge of the lumped uncertainties is required. To cope with actuator limitations, a smooth non-affine function of the control input is used in order to approximate the saturation constraint. System stability was proven using the Lyapunov theory. The approach was validated using numerical simulations and comparison analysis with existing attitude approaches. The obtained results confirmed the controller’s superior performance in terms of convergence rate, high attitude pointing accuracy and stability. Additionally, the proposed approach is inherently continuous and exhibits chattering free dynamics.

This paper is mainly dedicated to the challenging issue of fixed-time attitude control for a flexible spacecraft in the presence of actuator faults, external disturbances and coupling effect of flexible modes. The attitude controller is developed by employing a fixed-time nonsingular terminal sliding mode under which the convergence time is bounded and independent of the initial states. This robust attitude controller is able to provide superior properties such as fast fixed-time attitude manoeuvring with high pointing accuracy, singularity avoidance and chattering free. More specifically, a new reaching law is employed to provide convergence rate improvement as well as chattering alleviating simultaneously. The actuator fault problem is also considered and the attitude control is achieved even when the actuators experience severe faults. The proposed controller ensures that the closed-loop attitude system is stable in the sense of fixed-time stability concept. Furthermore, since the upper bound of external disturbances and flexible vibrations acting on the spacecraft is not available, an adaptation mechanism is presented. Numerical simulations demonstrate that the proposed controller is able to successfully accomplish attitude control with high attitude pointing accuracy and stability in spite of the actuator faults, flexible structures vibrations and external disturbances.

We conducted a two-center retrospective survey on standard MRI features including apparent diffusion coefficient mapping (ADC) of diffuse midline gliomas H3 K27M-mutant (DMG) compared to midline glioblastomas H3 K27M-wildtype (midGBM-H3wt). We identified 39 intracranial DMG and 18 midGBM-H3wt tumors. Samples were microscopically re-evaluated for microvascular proliferations and necrosis. Image analysis focused on location, peritumoral edema, degree of contrast enhancement and DWI features. Within DMG, MRI features between tumors with or without histomorphological GBM features were compared. DMG occurred in 15/39 samples from the thalamus (38%), in 23/39 samples from the brainstem (59%) and in 1/39 tumors involving primarily the cerebellum (2%). Edema was present in 3/39 DMG cases (8%) versus 78% in the control (midGBM-H3wt) group (p < 0.001). Contrast enhancement at the tumor rim was detected in 17/39 DMG (44%) versus 67% in control (p = 0.155), and necrosis in 24/39 (62%) versus 89% in control (p = 0.060). Strong contrast enhancement was observed in 15/39 DMG (38%) versus 56% in control (p = 0.262). Apparent diffusion coefficient (ADC) histogram analysis showed significantly higher skewness and kurtosis values in the DMG group compared to the controls (p = 0.0016/p = 0.002). Minimum relative ADC (rADC) values, as well as the 10th and 25th rADC-percentiles, were lower in DMGs with GBM features within the DMG group (p < 0.001/p = 0.012/p = 0.027). In conclusion, DMG cases exhibited markedly less edema than midGBM-H3wt, even if histomorphological malignancy was present. Histologically malignant DMGs and midGBM-H3wt more often displayed strong enhancement, as well as rim enhancement, than DMGs without histomorphological malignancy. DMGs showed higher skewness and kurtosis values on ADC-histogram analysis compared to midGBM-H3wt. Lower minimum rADC values in DMGs indicated malignant histomorphological features, likely representing a more complex tissue microstructure.

A new magnetic metal–organic framework (MMOF) constructed from MIL-101(Cr) and 1-(2-pyridylazo)-2-naphthol-modified magnetite nanoparticles was introduced for the ultrasound-assisted magnetic solid phase extraction (UA-MSPE) and speciation analysis of trace amounts of inorganic tin. Ultrasonic irradiation accelerated the mass transfer process in the sorption step and broke the affinity between the analyte and nanoadsorbent in the elution process. The MMOF exhibited high selectivity toward Sn(IV) at pH = 5.8. The Sn(II) concentration was determined after its oxidation to Sn(IV) and extracting total tin. After ultrasound-assisted sorption and elution steps, tin was determined with electrothermal atomic absorption spectrometry (ETAAS). The limit of detection, linear range and precision (RSD%) for Sn(IV) were 5.0 ng L−1, 15–1000 ng L−1 and 7.4%, respectively. The accuracy of the US-MSPE method was confirmed by employing a certified reference material. Finally, the method was utilized successfully for the fast and selective speciation analysis of Sn(IV) and Sn(II) in water and food samples.

Rosette-forming glioneuronal tumor (RGNT) is a rare tumor entity which has been reported mainly occurring in the fourth ventricle. It has been described as a benign lesion with limited extension into surrounding structures, including the cerebellar vermis, midbrain, and cerebral aqueduct. More recently, few cases involving also other midline structures have been documented as well. Here, we report about diagnosis and treatment of RGNT in the septum pellucidum in a pediatric patient which has not been described previously. A 7-year-old boy had a 3-week history of headache. Magnetic resonance imaging showed a solid mass in the septum pellucidum accompanied by hydrocephalus. The tumor was resected via a transcortical approach. Histological examination revealed the typical findings of a RGNT. At 2-year follow-up, there was no tumor recurrence, and clinical outcome was unremarkable. RGNT has to be considered in the differential diagnosis of pediatric midline tumors also outside of the fourth ventricle. Surgical resection is the first-line therapy which may result in beneficial outcome in the long term. The role of adjuvant therapy needs further definition since due to the rarity of this tumor entity, available data is very limited.

Various synthetic materials are used in neurosurgery and left in place intentionally during surgery for several purposes such as hemostasis, dural closure, or cranioplasty. Although leaving such substances in surgical sites is considered safe, in general, foreign body granuloma may occur months or years after intracranial surgery. Thus, far relatively little is known about treatment and outcome of such lesions. A systematic review of 3466 histopathological examinations after cranial surgeries achieved over a 13-year period was performed. After excluding patients with Teflon granulomas or infection, a total of 12 patients with foreign body granulomas induced by synthetic material used in a prior surgery were identified. Patient records, imaging studies, and histopathological data were analyzed. Furthermore, postoperative outcome was assessed. Mean age at the second surgery was 51 years (range, 11–68 years). The median time between the primary and the secondary surgery was 13 months (range, 1–545 months). Eight patients (75%) presented with signs and symptoms related to the foreign body granulomas. Total resection of the foreign body granulomas was performed in all patients. The granulomas were induced by oxidized cellulose polymer (n = 6), suture material (n = 3), Gelfoam (n = 1), methylmethacrylate (n = 1), and bone wax (n = 1). The mean postoperative follow-up time was 54 months (range 1–137 months). There was symptomatic improvement in all instances. Imaging studies did not demonstrate any recurrence. Despite its rarity, foreign body granuloma should be taken into consideration in the differential diagnosis of intracranial mass lesions especially in cases of suspected tumor recurrence after prior surgery. The pathogenesis of foreign body granuloma still needs further clarification. Our study demonstrates that they have good prognosis after surgical removal.

This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

Objective Despite contemporary diagnostic and therapeutic techniques intracranial emergencies in the obstetric setting pose still a major challenge for the clinicians. There are limited guidelines and differing ethical views. Multidisciplinary teams are needed to support the pregnant woman in a way that she can deliver a viable and healthy child. The aim of the present study was to scrutinize the management of intracranial emergencies during pregnancy which needed urgent neurosurgical treatment. Patients and methods Data of all pregnant women who presented with newly diagnosed intracranial pathologies and neurological symptoms caused by these pathologies in an emergency setting were collected over a 10-year period (2008–2018). Patient characteristics including maternal age, gestational age, and preoperative work-up of both mother and fetus were recorded. Furthermore, the surgical treatment, mode of delivery, and neonatal and maternal outcomes were analysed. Results The mean maternal age was 32.7 years and most patients were in their third trimester. There was one twin pregnancy (total of 12 fetuses). Five out of eleven pregnant women suffered from intracerebral haemorrhage (epidural haematoma (1), arteriovenous malformation (1), subarachnoid haemorrhage (2) and intracerebral haemorrhage (1)) and the other six patients had intracranial neoplasms (primary meningeal sarcoma (1), trigeminal schwannoma (1), anaplastic astrocytoma (2), glioblastoma (1) and sphenoid wing meningioma (1)).Neurosurgical procedures were performed via craniotomies in eight patients. A stereotactic biopsy via a frontal burr hole was achieved one patient. The two other patients with subarachnoid haemorrhage due to rupture of PICA aneurysms were treated with coil embolization. Depending on the gestational age and the clinical condition of the pregnant women it was decided to perform an emergency Caesarean section prior to further therapeutic measures in seven patients. Two out of 12 fetuses were unviable. Six women survived, while five women succumbed to the intracranial pathology. Conclusion The individualized treatment approach in this peculiar obstetric scenario needs to consider various issues such as the clinical condition of the pregnant woman, prognosis of the disease, gestational age and the status of the pregnancy. The primary concern in this context must be the mother`s health and safety. Caesarean section is the primary mode of delivery in most cases. While contemporary care can insure survival for the majority of infants, maternal mortality still poses an extraordinary challenge. Interdisciplinary consulting of the patient and/or her family is necessary to develop a treatment strategy for both the expectant woman and her offspring.

Background Low back pain is a common complaint during pregnancy. However, spinal pathologies, which manifest with severe pain, radiculopathy, and acute neurologic deficits because of disk herniation or mass lesions require special attention. Here, we present our interdisciplinary experience in the surgical management of spinal emergencies during pregnancy. Methods The data of pregnant women who underwent surgery for spinal pathologies over a 10-year period were collected. Patient-related characteristics such as maternal age, gestational age, preoperative workup, signs and symptoms of mothers, and diagnostic procedures were evaluated. After an interdisciplinary conference, individualized treatment plans regarding available options were developed. Fetal Doppler and cardiotocography were obtained before and after surgery. Results Nine pregnant women presented with spinal disorders and underwent spinal emergency surgery within the study period. The mean maternal age was 32.2 years. Six women presented with lumbar disk herniations manifesting as severe sciatica or foot drop and 3 patients had thoracic mass lesions resulting in cauda equine syndrome and/or ataxia. The mean gestational age at the time of presentation was 26.5 weeks. Caesarean sections were performed in 3 women prior to the neurosurgical procedure, whereas the pregnancies were maintained in the 6 other patients. Eight infants who were healthy at birth had an unremarkable development. Conclusions Surgery for spinal emergencies in pregnancy can be performed safely according to individual treatment plans developed by an interdisciplinary team taking into account the expectant mother's decision. Maintenance of pregnancy is possible and feasible in most patients.

A novel magnetic metal-organic framework (MOF) consisting of MIL-101(Fe) and morin-modified magnetite nanoparticles was synthesized and utilized for the extractive speciation analysis of V(IV) and V(V) at trace levels. The magnetic MOF exhibits selectivity toward V(V) at pH = 5.8. The concentration of V(IV) can be determined after its oxidation to V(V) and extracting total vanadium. After sorption and elution steps, vanadium can be determined by ETAAS. Under the optimal conditions, the limit of detection, linearity and the relative standard deviation for V(V) are 3.0 ng L−1, 10–750 ng L−1 and 6.0%, respectively. The new method was validated by employing two certified reference materials. Finally, the method was successfully utilized for fast and selective speciation analysis of V(IV) and V(V) in water and food samples.

Background Different inflammatory diseases can manifest as intracranial lesions. They may be indistinguishable from intracranial neoplasms in the clinical setting, imaging studies, or laboratory studies. The value of surgery in the diagnosis and the treatment of such lesions is still unclear. Methods A total of 3066 reports of histopathologic examinations over a 10-year period were reviewed. Forty patients with an inflammatory intracranial lesion were identified. Clinical, radiologic, and follow-up data were analyzed and the diagnostic and therapeutic value of surgery was assessed. Results We identified 24 women and 16 men (mean age, 47 years). The diameter of the lesion varied between 1 and 5.5 cm (mean, 2.6 cm). The location of the inflammatory lesion was intracerebral supratentorial (n = 18, 45%), intrasellar/suprasellar (n = 5, 12.5%), cerebellar (n = 5, 12.5%), in the brainstem (n = 4, 10%), in the cerebellopontine angle (n = 3, 7.5%), meningeal (n = 3, 7.5%), and at other locations (n = 6, 15%). Seventeen patients underwent surgical removal of the mass lesion, whereas in 23 patients a biopsy was taken. The lesions were classified into 7 groups: specific (infectious) granuloma (n = 10, 25%), unspecific granuloma (n = 7, 17.5%), idiopathic inflammatory pseudotumor (n = 5, 12.5%), demyelinating lesions (n = 5, 12.5%) encapsulated hematoma (n = 4, 10%), organized cerebral infarction (n = 3, 7.5%), and vasculitis (n = 4, 10%). Surgery was judged as valuable in 35 patients (87.5%). Conclusions The differential diagnosis of intracranial inflammatory lesions involves a wide spectrum. Surgery has a diagnostic and/or therapeutic value in most entities and clinical circumstances. However, attention must be taken to avoid surgery without a therapeutic or diagnostic value for the patient.

Introduction Acute rejection following kidney transplantation (KTx) is still one of the challenging complications leading to chronic allograft failure. The aim of this study was to investigate the role of microdialysis (MD) in the early detection of acute graft rejection factor following KTx in porcine model. Methods Sixteen pigs were randomized after KTx into case (n = 8, without immunosuppressant) and control groups (n = 8, with immunosuppressant). The rejection diagnosis in our groups was confirmed by histopathological evidences as “acute borderline rejection”. Using MD, we monitored the interstitial concentrations of glucose, lactate, pyruvate, glutamate and glycerol in the transplanted grafts after reperfusion. Results In the early post-reperfusion phase the lactate level in our case group was significantly higher comparing to the control group and remained in higher levels until the end of monitoring. The lactate to pyruvate ratio showed a considerable increase in the case group during the post-reperfusion phase. The other metabolites (glucose, glycerol, glutamate) were nearly at the same levels at the end of our monitoring in both study groups. Conclusion The increase in lactate and lactate to pyruvate ratios seems to be an indicator for early detection of acute rejection after KTx. Therefore, MD as a minimally invasive measurement tool may help to identify the need to immunosuppression adjustment in the early KTx phase before the clinical manifestation of the rejection.

Navigated intracranial endoscopy with conventional technique usually requires sharp head fixation. In children, especially in those younger than 1 year of age and in older children with thin skulls due to chronic hydrocephalus, sharp head fixation is not possible. Here, we studied the feasibility, safety, and accuracy of electromagnetic (EM)-navigated endoscopy in a series of children, obviating the need of sharp head fixation. Seventeen children (ten boys, seven girls) between 12 days and 16.8 years (mean age 4.3 years; median 14 months) underwent EM-navigated intracranial endoscopic surgery based on 3D MR imaging of the head. Inclusion criteria for the study were intraventricular cysts, arachnoid cysts, aqueduct stenosis for endoscopic third ventriculostomy (ETV) with distorted ventricular anatomy, the need of biopsy in intraventricular tumors, and multiloculated hydrocephalus. A total of 22 endoscopic procedures were performed. Patients were registered for navigation by surface rendering in the supine position. After confirming accuracy, they were repositioned for endoscopic surgery with the head fixed slightly on a horseshoe headholder. EM navigation was performed using a flexible stylet introduced into the working channel of a rigid endoscope. Neuronavigation accuracy was checked for deviations measured in millimeters on screenshots after the referencing procedure and during surgery in the coronal (z = vertical), axial (x = mediolateral), and sagittal (y = anteroposterior) planes. EM-navigated endoscopy was feasible and safe. In all 17 patients, the aim of endoscopic surgery was achieved, except in one case in which a hemorrhage occurred, blurring visibility, and we proceeded with open surgery without complications for the patient. Navigation accuracy for extracranial markers such as the tragus, bregma, and nasion ranged between 1 and 2.5 mm. Accuracy for fixed anatomical structures like the optic nerve or the carotid artery varied between 2 and 4 mm, while there was a broader variance of accuracy at the target point of the cyst itself ranging between 2 and 9 mm. EM-navigated endoscopy in children is a safe and useful technique enhancing endoscopic intracranial surgery and obviating the need of sharp head fixation. It is a good alternative to the common opto-electric navigation system in this age group.

Background: The incidence of diabetes has been steadily increasing. The only curative option for diabetes is pancreas transplantation (PTx). Porcine models are valuable because of their anatomical and physiological similarities to human beings. Our aim is to introduce a simplified technique of PTx in a porcine model. Methods: In Landrace pigs (n = 32), after median laparotomy, the pancreas was mobilized, and the portal and splenic veins were divided. The proper hepatic and splenic arteries and the bile duct were also prepared, and the duodenal bulb was prepared and stapled. The third portion of the duodenum was freed up to the ligament of Treitz and stapled, and the renal arteries were ligated. After systemic heparinization, the pancreas was perfused through the abdominal aorta with histidine-tryptophan-ketoglutarate solution. The portal and splenic veins were cut for evaluating the sufficiency of perfusion. Whole pancreaticoduodenal graft was procured along with an aortic jump graft containing mesenteric and celiac trunks. In recipients, after total pancreatectomy, the suprarenal inferior vena cava and infrarenal aorta were prepared for vascular anastomosis in an end-to-side manner. After pancreas reperfusion, duodenoduodenostomy was performed in an end-to-side manner. Results: Median cold and warm ischemia times were 10 h (range, 9-14 h) and 50 min (range, 35-80 min), respectively. The hemodynamic status was stable throughout the operation. The median follow-up period was 7 days (range, 4-10). There were no major intra- and postoperative complications. Conclusion: By using an aortic jump graft, there was no need to perform additional arterial reconstruction resulting in a short warm ischemic and operation time. End-to-side portocaval and duodenoduodenal anastomoses make this model of PTx a very feasible method for experimental evaluations.

Summary Background Brain metastases (BM) from the gastrointestinal tract (GIT) cancers are relatively rare. Despite those advances in diagnostic and treatment options, life expectancy and quality of life in these patients are still poor. In this review, we present an overview of the studies which have been previously performed as well as a comprehensive strategy for the assessment and treatment of BM from the GIT cancers. Method To obtain information on brain metastases from GIT, we performed a systematic review of Medline, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL). The collected data included patient characteristics, primary tumor data and brain metastases data. Result In our search of the literature, we found 74 studies between 1980 and 2011, which included 2538 patients with brain metastases originated from gastrointestinal cancer. Analysis of available data showed that among 2538 patients who had brain metastases from GIT, a total of 116 patients (4.57%) had esophageal cancer, 148 patients (5.83%) had gastric cancer, 233 patients (9.18%) had liver cancer, 13 patients had pancreas cancer (0.52%) and 2028 patients (79.90%) had colorectal cancer. The total median age of the patients was 58.9 years. Conclusion Brain metastases have been considered the most common structural neurological complication of systemic cancer. Due to poor prognosis they influence the survival rate as well as the quality of life of the patients. The treatment of cerebral metastasis depends on the patients' situation and the decisions of the treating physicians. The early awareness of a probable metastasis from GI to the brain will have a great influence on treatment outcomes as well as the survival rate and the quality-of-life of the patients.

Background Brain death (BD) is a donor-associated risk factor that negatively affects transplantation outcome. The inflammation associated with BD appears to have a negative effect on organ quality. Complement activation, apoptosis, and pro-inflammatory cytokine and chemokine expression are significantly increased after BD. To better understand this process, we investigated plasma chemokine and cytokine levels for 8 h after BD in a rodent model. Methods Thirteen healthy adult male Sprague Dawley rats were intubated and mechanically ventilated. After induction of BD, animals were kept hemodynamically stable for 8 h. A panel of immune response factors, including cytokines and chemokines, were measured immediately prior to the induction of BD and at 1, 4, and 8 h after BD by multiplex analyses in 10 rats. Results In the early phase of BD, we observed an increase in heart rate and a decrease in mean arterial pressure. Only limited fluctuations were noted in the partial pressure of O2, O2 saturation, and HCO3. Monocyte-/macrophage- and lymphocyte-derived mediators (IL-2, IL-4, and IFN-γ) increased steadily during the 8-hour monitoring period. Conclusions The increase in immune responses, particularly pro-inflammatory responses, after BD is time-dependent. Cytokines and chemokines from donors and recipients require further investigation to determine the optimal time frames for organ transplantation in rodent models and humans.

Experimental animal research has been pivotal in the development of clinical liver transplantation (LTx). Results obtained in these experiments have been applied in clinic and clinical challenges have been scrutinized in animal laboratories. Porcine model is an optimal model in the field of experimental LTx research. Here, we present the various techniques of experimental LTx in the porcine model in detail. Different methods and modifications have been described. The following major steps have been discussed in detail: donor liver preparation, recipient operation including recipient hepatectomy, and reconstruction phase, including the reconstruction of suprahepatic inferior vena cava (SHIVC), portal vein (PV), infrahepatic inferior vena cava (IHIVC), hepatic artery (HA) and bile duct (BD). IHIVC and SHIVC are anastomosed end to end directly or with the use of prosthesis anastomosed side to side. The PV anastomosis is performed end to end between donor and recipient PV, Cuff method or Stump method. Arterialization has been accomplished via carrel patch or donor HA end to end with recipient HA. There are three major methods for reconstruction of BD: end to end or end to side choledochocholedochostomy or choledojejunostomy with Roux-en-Y jejunal loop. Each method has advantages and disadvantages regarding the objectives of the study; the most physiological techniques may be preferred for long-term survival studies, while the faster techniques may be selected for experimentations aiming the direct postoperative phase.

Background: Microdialysis (MD) can detect organ-related metabolic changes before they become measurable in plasma through the biochemical parameters. This study aims to evaluate the early detection of metabolic changes during experimental kidney transplantation (KTx). Material and methods: During preparation of 8 donor kidneys, one MD catheter was inserted in the renal cortex and samples were collected. After a 6-hour cold ischemia time (CIT), kidneys were implanted in the 8 recipient pigs. Throughout the warm ischemia time (WIT) and after reperfusion, kidneys were monitored. The interstitial glucose, lactate, pyruvate, glutamate, and glycerol concentrations were evaluated. Results: A significant decline in glucose level was observed at the end of CIT. The lactate level was reduced to the minimum point of 0.35 ± 0.08 mmol/L in CIT. After reperfusion, lactate values raised significantly. During the WIT, the pyruvate level increased, continued until the end of the WIT. For glutamate, a steady increase was noted during explantation, CIT, WIT, and early reperfusion phases. The increase of glycerol value continued in the early postreperfusion, which was then followed by a sharp decline. Conclusion: MD is a fast and simple minimally invasive method for measurement of metabolic substrates in renal parenchyma during KTx. MD offers the option of detecting minor changes of interstitial glucose, lactate, pyruvate, glutamate, and glycerol in every stage of KTx. Through the use of MD, metabolic changes can be continuously monitored during the entire procedure of KTx.

Background. In kidney transplantation (KTx), vascular thrombosis has a major impact on morbidity and graft survival. The ischaemia, caused by thrombosis, can lead to interstitial metabolite changes. The aim of this experimental study was to create conditions in which the graft would be prone to vascular thrombosis following KTx and then to evaluate the role of microdialysis (MD) for its early detection. Methods. Sixteen randomized pigs in the control group received heparin and immunosuppressive drugs, while the case group received none. Based on histopathological evidence of vascular thrombosis, the case group was subdivided into mildly and severely congested subgroups. Using MD, we evaluated the interstitial concentrations of glucose, lactate to pyruvate ratio, glutamate and glycerol in the transplanted grafts during different phases of KTx. Results. Following reperfusion, we noted considerable changes. The severely congested subgroup showed a low and decreasing level of glucose. Only in this group did the lactate to pyruvate ratio continue to increase until the end of monitoring. The glycerol level increased continuously in the entire case group and this increase was most significant in the severely congested subgroup. In all of the study groups, glutamate concentration remained in a low steady state until the end of monitoring. Conclusions. MD can be an appropriate method for early detection of vascular complications after KTx. Decreasing glucose levels, increased lactate to pyruvate ratio and increased glycerol levels are appropriate indicators for early detection of vascular thromboses following KTx. Particularly, the glycerol level could predict the necessity and urgency of intervention needed to ultimately save the transplanted kidney.

Without adequate prophylaxis, liver transplantation (LTx) is frequently followed by hepatitis B virus (HBV) reinfection, which results in rapidly progressing liver disease and significantly decreased overall survival. In the last two decades, significant progress has been made in the prophylaxis and treatment of HBV.We present an overview of different protocols and regimens used for prophylaxis of HBV reinfection after LTx and describe the protocol implemented at our center. Following LTx, HBV reinfection can be effectively prevented by administration of anti-hepatitis B immunoglobulin (HBIg) alone or more recently in combination with antiviral nucleoside/nucleotide analogs (NUCs). Several studies reported good results with the use of HBIg alone, but combination treatment with HBIg and NUCs has proven to be a superior prophylactic regimen for HBV recurrence. At present, combination therapy (HBIg and a nucleoside or nucleotide analog) is the gold standard used in many transplantation centers. This preventive regimen reduces the risk of a recurrence of HBV infection and thereby the need for re-transplantation. Future and ongoing studies will show how long HBIg must be given after transplantation, especially when used in combination with potent antivirals, such as entecavir or tenofovir.

During the last decades, the disparity between the organ supply and the demand for kidney transplantation in Europe has led to consider living donors as a more acceptable option. In the last 7 years, we have established an interdisciplinary supporting transplant team to increase the rate of living donation. After 2001, the new interdisciplinary transplant team consisted of a transplant surgeon, a nephrologist, a pediatrician, a radiologist, a psychologist, a transplant coordinator, and a transplant nurse. We performed a prospective analysis to examine the effect of implementing this team on our living donation program. Demographic data, the annual number of procedures, the duration of waiting, and the cold ischemia time were evaluated among brain-dead and living donors. From January 2002 until December 2008, the number of patients who were annually on the waiting list increased 42% (from 377 to 536 patients). Consequently, the number of the total kidney transplants increased from 81 to 120 with an annual median of 98 cases. By implementing the interdisciplinary transplant team, a significant increase of living kidney donors was observed: from 18 to 42 cases; median = 27). In the last 7 years, a total number of 796 kidney transplants have been performed: 567 from brain-dead and 229 from living donors. In 2001, the waiting list times for recipients who received grafts from brain-dead versus living donors were 1356 versus 615 days respectively. Compared with 2008, the duration on the waiting list decreased significantly for patients receiving a living donor graft, whereas there was a slight increase for the patients in the brain-dead group: brain death versus living donors: 1407 versus 305 days. The interdisciplinary approach has also reduced the cold ischemia time for the living donor recipients: 3 hours and 42 minutes in 2001 versus 2 hours and 50 minutes in 2008. During the last years, by implementing an interdisciplinary transplant team, supporting living donor procedures has produce a gradual increase in the number of kidney transplants from living donors with a remarkable decrease in waiting and cold ischemia times, the latter presumably influencing graft quality.

Caring for a brain dead potential organ donor requires a shift in critical care from the extensive treatment of increased intracranial pressure towards strategies to maintain donor organ function. Suboptimal, unstandardized critical care management of organ donors, however, is one of the main reasons for insufficient organ procurement. The pathophysiological changes following brain death entail a high incidence of complications including hemodynamic instability, endocrine and metabolic disturbances, and disruption of internal homeostasis that jeopardize potentially transplantable organs. Strategies for the management of organ donors exist and consist of the normalization of donor physiology. This has resulted in standardized efforts to improve the critical care delivered to potential organ donors, increasing not only the number, but also the quality of suitable organs and aiming at an optimal outcome for the recipients. In this review, we discuss the pathophysiological changes associated with brain death and present the current guidelines at our department, which are optimized based on available literature.

With advancements in the operative techniques, patient survival following liver transplantation (LTx) has increased substantially. This has led to the acceleration of pre-existing kidney disease because of immunosuppressive nephrotoxicity making additional kidney transplantation (KTx) inevitable. On the other hand, in a growing number of patients on the waiting list to receive liver, long waiting time has resulted in adverse effect of decompensated liver on the kidney function. During the last two decades, the transplant community has considered combined liver kidney transplantation (CLKTx) to overcome this problem. The aim of our study is to present an overview of our experience as well as a review of the literature in CLKTx and to discuss the controversy in this regard. All performed CLKTx (n = 22) at our institution as well as all available reported case series focusing on CLKTx are extracted. The references of the manuscripts were cross-checked to implement further articles into the review. The analyzed parameters include demographic data, indication for LTx and KTx, duration on the waiting list, Model for End-Stage Liver Disease (MELD) score, Child-Turcotte-Pugh (CTP) score, immunosuppressive regimen, post-transplant complications, graft and patient survival, and cause of death. From 1988 to 2009, a total of 22 CLKTx were performed at our institution. The median age of the patients at the time of CLKTx was 44.8 (range: 4.5-58.3 yr). The indications for LTx were liver cirrhosis, hyperoxaluria type 1, polycystic liver disease, primary or secondary sclerosing cholangitis, malignant hepatic epithelioid hemangioendothelioma, cystinosis, and congenital biliary fibrosis. The KTx indications were end-stage renal disease of various causes, hyperoxaluria type 1, polycystic kidney disease, and cystinosis. The mean follow-up duration for CLKTx patients were 4.6 +/- 3.5 yr (range: 0.5-12 yr). Overall, the most important encountered complications were sepsis (n = 8), liver failure leading to retransplantation (n = 4), liver rejection (n = 3), and kidney rejection (n = 1). The overall patient survival rate was 80%. Review of the literature showed that from 1984 to 2008, 3536 CLKTx cases were reported. The main indications for CLKTx were oxalosis of both organs, liver cirrhosis and chronic renal failure, polycystic liver and kidney disease, and liver cirrhosis along with hepatorenal syndrome (HRS). The most common encountered complications following CLKTx were infection, bleeding, biliary complications, retransplantation of the liver, acute hepatic artery thrombosis, and retransplantation of the kidney. From the available data regarding the need for post-operative dialysis (n = 673), a total of 175 recipients (26%) required hemodialysis. During the follow-up period, 154 episodes of liver rejection (4.3%) and 113 episodes of kidney rejection (3.2%) occurred. The cumulative 1, 2, 3, and 5 yr survival of both organs were 78.2%, 74.4%, 62.4%, and 60.9%, respectively. Additionally, the cumulative 1, 2, 3, and 5 yr patient survival were 84.9%, 52.8%, 45.4%, and 42.6%, respectively. The total number of reported deaths was 181 of 2808 cases (6.4%), from them the cause of death in 99 (55%) cases was sepsis. It can be concluded that there is still no definitive evidence of better graft and patient survival in CLKTx recipients when compared with LTx alone because of the complexity of the exact definition of irreversible kidney function in LTx candidates. Additionally, CLKTx is better to be performed earlier than isolated LTx and KTx leading to the avoidance of deterioration of clinical status, high rate of graft loss, and mortality. Shorter graft ischemia time and more effective immunosuppressive regimens can reduce the incidence of graft malfunctioning in CLKTx patients. Providing a model to reliably determine the need for CLKTx seems necessary. Such a model can be shaped based upon new and precise markers of renal function, and modification of MELD system.

Introduction. The aim of the present study was to evaluate the feasibility of a technique that uses solely the transhiatal approach to create a high intrathoracic esophagogastric anastomosis after laparoscopic transhiatal resection of the distal esophagus. Method. Using a laparoscopic approach, the esophagi of 10 midsized pigs were dissected and transected as high as possible in the thorax, and the anvil of a circular stapler was introduced perorally into the esophageal stump. Through a midline short laparotomy, the circular stapler was inserted into the gastric tube and advanced through the hiatus to be connected with the anvil and create the anastomosis. Results. Development of the technique was completed within the first 6 experiments. The last 4 operations were entirely successful, standardized, and easily reproducible. Conclusion. The technique is feasible in this experimental setting. Further studies are required to establish if there is a clinical role for this technique in esophageal surgery.

Changes in liver microcirculation are considered essential in assessing ischemia-reperfusion injury, which in turn has an impact on liver graft function and outcome following liver transplantation (LTx). The aim of this study was to introduce dynamic magnetic resonance imaging (dMRI) as a new technique for overall quantification of hepatic microcirculation and compare it to perfusion measured by laser Doppler flowmetry (LDF; hepatic artery/portal vein) and thermal diffusion (TD). The study included 3 groups, measuring hepatic blood flow and microcirculation with the help of TD, LDF, and dMRI. In group I (9 landrace pigs; 26 ± 5 kg), the native liver before and after partial portal occlusion was studied; in group II (6 landrace pigs; 25.5 ± 4.4 kg), the liver 24 hours after LTx was studied; and in group III (14 patients), the liver on days 4 to 7 following LTx was studied. A close correlation was found between dMRI measurements and TD (r = 0.7–0.9, P < 0.01) in 4 defined regions of interest. Portal blood flow and partial occlusion of the portal vein were accurately detected by LDF flowmetry and correlated well with dMRI (r = 0.95, P < 0.01). In the clinical setting, representative TD measurements in segment 4b of the transplanted liver correlated well with dMRI analysis in other segments. Quantification of the portal blood flow and imaging of the whole liver could be performed simultaneously by dMRI. In conclusion, dMRI has been proved to be a sensitive modality for the quantification of liver microcirculation and hepatic blood flow in experimental and clinical LTx. It allows for a synchronous, noninvasive assessment of macrocirculation and microcirculation of the liver and could become a valuable diagnostic tool in advanced liver surgery and transplantation. Liver Transpl 15:693–700, 2009. © 2009 AASLD.

Esophageal cancer is one of the common gastrointestinal cancers around the world. Lymph nodes, liver, and peritoneum are the most common sites of its metastasis. Rarely, it can also metastasize to the brain. The size of the primary tumor and the stage of disease seem to be associated with the brain metastasis, although the pathway that esophageal cancer cells take to reach the brain is not well recognized. Brain metastasis from esophageal cancer has a very poor prognosis and the literature on this topic is primarily built on case reports or small case series. Therefore, no clear management strategy has been defined for these patients. In this chapter, we discuss what is known and what needs to be recognized about the brain metastasis from esophageal cancer and cover possible diagnostic and therapeutic strategies in this situation.