Urte Zurbuchen

Impact of sleep deprivation on medium-term psychomotor and cognitive performance of surgeons: prospective cross-over study with a virtual surgery simulator and psychometric tests.

BACKGROUND Despite recent work hour restrictions, 24-hour calls remain an important part of patient care. The aim of this study was to assess the impact of 24-hour night calls on the psychomotor and cognitive skills of surgeons with a virtual surgery simulator (VSS) and psychometric tests. We hypothesized that sleep loss impairs surgical skills and concentration performance. METHODS Seventeen surgery residents (test group) and 13 medical students (reference group) performed a 5-day training program on the VSS. The test group was then assessed during a night call on 4 test points (8 am and 4 pm on the on-call day, 8 am on the postcall day, and 8 am on the recovery day) to assess the effects of sleep loss on these surgery residents. The reference group performed the same tests but without a night call. RESULTS The training resulted in a homogenous performance level for both groups. The average time for the test group was 26 minutes. The analysis between rested and sleep-deprived participants (6.5 +/- 0.9 vs 2.9 +/- 1.4 hours of night sleep) in the on-call part showed no performance differences. No impairment was found for the VSS and the cognitive tests within the test group between the start of the working day and the start of the postcall day after the night of relative sleep loss. The subgroup analysis showed no significant differences regarding the amount of night sleep and laparoscopic experience. CONCLUSION No performance impairment was found for surgeons with a VSS and standardized cognitive tests after a night of relative sleep loss. Although there is no doubt that sleep deprivation ultimately impairs human functioning, typical surgical skills do not necessarily deteriorate with a limited amount of sleep loss under clinical conditions.

Tumor-necrosis-factor-related apoptosis-inducing-ligand (TRAIL)-mediated death of neurons in living human brain tissue is inhibited by flupirtine-maleate

Neuronal damage mediated by the TRAIL-system might be involved in the pathogenesis of neuroinflammatory diseases of the central nervous system. Here we used an investigator-independent approach to quantify TRAIL-mediated death of total CNS cells and neurons in a living human brain slice culture system, a model which is much closer to the in vivo situation than dissociated cell culture. We observed dose-dependent TRAIL-mediated death of both total human CNS cells and neurons, which was prevented by flupirtine-maleate, a centrally acting analgesic drug with proposed neuroprotective properties. Our data suggest flupirtine-maleate as an orally available neuroprotective approach in the course of neuroinflammation.

Determination of the temperature-dependent electric conductivity of liver tissue ex vivo and in vivo: Importance for therapy planning for the radiofrequency ablation of liver tumours

Introduction: Knowledge about the changes in the electric conductivity during the coagulation process of radiofrequency ablation of the liver is a prerequisite for the predictability of produceable thermonecrosis in the liver. Materials and methods: Continuous measurements of the electric conductivity σ in ex vivo porcine liver (n = 25) were done during the coagulation and cooling process at the temperature range of the radiofrequency ablation at a frequency of 470 kHz relevant for the radiofrequency ablation. Measurements of the electric conductivity were performed in both perfused porcine liver (n = 3) and a human surgical specimen from a colorectal liver metastasis. Results: At a body temperature of 37°C, conductance σ was 0.41 siemens per metre (0.32 S/m; 0.52 S/m). Conductance σ increased continuously and uniformly at a temperature of 77°C. Maximum conductance σ with 0.79 S/m (0.7 S/m; 0.87 S/m) was reached at 80°C. A continuous reduction of conductance was observed during the cooling phase. At 37°C, the specific conductance σ in the healthy perfused porcine liver was 0.52 S/m, 0.55 S/m and 0.57 S/m (mean 0.55 S/m). The electric conductivity of the human colorectal liver metastasis was clearly higher. Conclusion: Changes in the specific conductivity during the coagulation and the cooling phase play an important role for the produceable size of a coagulation necrosis and necessitates an adaptation of the therapy parameters during radiofrequency ablation.

Complications after end-to-end vs. side-to-side anastomosis in ileocecal Crohn's disease--early postoperative results from a randomized controlled multi-center trial (ISRCTN-45665492).

BackgroundRecurrent Crohn’s disease activity at the site of anastomosis after ileocecal resection is of great surgical importance. This prospective randomized multi-center trial with an estimated case number of 224 patients was initially planned to investigate whether stapled side-to-side anastomosis, compared to hand-sewn end-to-end anastomosis, results in a decreased recurrence of Crohn’s disease following ileocolic resection (primary endpoint). The secondary endpoint was to focus on the early postoperative results comparing both surgical methods. The study was terminated early due to insufficient patient recruitment and because another large study investigated the same question, while our trial was ongoing.Methods and study designPatients with stenosing ileitis terminalis in Crohn’s disease who underwent an ileocolic resection were randomized to side-to-side or end-to-end anastomosis. Due to its early discontinuation, our study only investigated the secondary endpoints, the early postoperative results (complications: bleeding, wound infection, anastomotic leakage, first postoperative stool, duration of hospital stay).ResultsFrom February 2006 until June 2010, 67 patients were enrolled in nine participating centers. The two treatment groups were comparable to their demographic and pre-operative data. BMI and Crohn’s Disease Activity Index were 22.2 (±4.47) and 200.5 (±73.66), respectively, in the side-to-side group compared with 23.3 (±4.99) and 219.6 (±89.03) in the end-to-end group. The duration of surgery was 126.7 (±42.8) min in the side-to-side anastomosis group and 137.4 (±51.9) min in the end-to-end anastomosis group. Two patients in the end-to-end anastomosis group developed an anastomotic leakage (6.5%). Impaired wound healing was found in 13.9% of the side-to-side anastomosis group, while 6.5% of the end-to-end anastomosis group developed this complication. The duration of hospital stay was comparable in both groups with 9.9 (±3.93) and 10.4 (±3.26) days, respectively.ConclusionsBecause of the early discontinuation of the study, it is not possible to provide a statement about the perianastomotic recurrence rates regarding the primary endpoint. With regard to the early postoperative outcome, we observed no difference between the two types of anastomosis.

Clostridium difficile infection of the small bowel—two case reports with a literature survey

IntroductionDiseases associated with Clostridium difficile range from antibiotic-related diarrhea to pseudomembranous enterocolitis, and are serious nosocomial infections with high morbidity and mortality. The C. difficile infection has thus far been regarded as a disease typically affecting the colon. However, the literature contains an increasing number of reports describing infections of the small bowel with fulminant clinical courses and high mortality rates of 60–83%. We think this situation is not very well known.MethodsWe present two cases of confirmed C. difficile enteritis and a survey of the literature.ConclusionC. difficile enteritis is characterized by a rising incidence, a sometimes fulminant clinical course, and high mortality rates. Early diagnosis of the disease by toxin detection and endoscopy is of paramount importance and can play a substantial role in improving outcomes.

Bipolar Radiofrequency Ablation for Nodular Thyroid Disease—Ex Vivo and In Vivo Evaluation of a Dose-Response Relationship

BACKGROUND The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like radiofrequency ablation (rfA) are increasingly used to treat tumors of parenchymatous organs, and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for rfA of thyroid nodules. MATERIAL AND METHODS Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n=110) and in vivo (n=10) using a bipolar radiofrequency system; rf was applied in a power range of 10-20 watts. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The transversal and axial lesion diameters were measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed. RESULTS The inducible lesion volumes were between 0.91±0.71 cm(3) at 20W and 2.80±0.85 cm(3) at 14W. The maximum temperatures after rf ablation were between 44.0±9.7°C and 61.6±13.9°C at a distance of 5 mm and between 30.0±8.6°C and 53.5±8.6°C at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) dehydrogenase activity in thermal lesions as a sign of irreversible cell damage. CONCLUSION This study is the first to demonstrate a dose-response relationship for rfA of thyroid tissue. rfA is suitable for singular thyroid nodules and induces reproducible, clinically relevant lesions with irreversible cell damage in an appropriate application time.

Ex vivo and in vivo evaluation of laser‐induced thermotherapy for nodular thyroid disease

The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like laser‐induced thermotherapy (LITT) are increasingly used to treat tumors of parenchymatous organs and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose–response relationship for LITT of thyroid nodules.

Minimal vascular flows cause strong heat sink effects in hepatic radiofrequency ablation ex vivo.

The present paper aims to assess the lower threshold of vascular flow rate on the heat sink effect in bipolar radiofrequency ablation (RFA) ex vivo.

Measuring and optimizing results in multipolar RFA: Techniques and early findings in an experimental setting

Radiofrequency ablation (RFA) has shown to be a reasonable alternative for the treatment of hepatic tumors and metastases although multiple limitations remain. Cooling effects due to larger vessels can prevent complete coverage and may lead to early tumor relapse. This preliminary in vivo pig study combines the use of multipolar RFA with three applicators (six electrodes) and interrupted liver perfusion using Pringles maneuver to overcome the most serious limitations. Furthermore, immediate detection of incomplete RFA is important to revise ablation. We used contrast enhanced computed tomography (CECT) to evaluate post ablation results in comparison to macroscopic images in healthy pig liver. We found significantly (p = 0.001) larger ablation zones and no affection by larger vessels with interrupted liver perfusion. This allows effective RFA for larger tumors. Immediate postinterventional CECT provided comparable results (r = 0.985) to macroscopic evaluation.

[Clinical studies outside university clinics : What are the problems to implement this?].

ZusammenfassungDie Forderung nach hochwertiger evidenzbasierter Therapie in der operativen Medizin in Deutschland und das Bewusstsein über die meist erheblich mangelhafte Qualität der chirurgischen Studien macht die Notwendigkeit von randomisiert-kontrollierten Studien deutlich. In 6 öffentlich geförderten operativen Studienzentren wird seit 2006 an der Schaffung einer professionellen Infrastruktur für chirurgische Studien gearbeitet. Ziel ist die Initiierung chirurgischer Multicenterstudien, die durch regionale Vernetzung effektiv durchgeführt werden können. Um eine zeitgerechte Patientenrekrutierung in diesen Studien zu sichern, ist es essenziell, in Zukunft nichtuniversitäre chirurgische Kliniken in die Studiendurchführung zu integrieren. Mithilfe einer Fragebogenaktion in nichtuniversitären chirurgischen Kliniken in Berlin und Brandenburg wurden das Interesse, die Studienerfahrungen und die strukturellen Gegebenheiten in diesen Kliniken evaluiert. Der vorliegende Beitrag diskutiert anhand der Ergebnisse dieser Umfrage, wie zukünftig nichtuniversitäre chirurgische Kliniken in die aktive Studiendurchführung eingebunden werden können und wie zu einer hohen Patientenrekrutierung motiviert werden kann.AbstractThe demand for high quality evidence-based surgical treatment in Germany and awareness of the poor quality of surgical trials highlight the basic necessity of randomized controlled trials. In six surgical trial centers a professional infrastructure for surgical trials is in the process of being established since 2006.The aim is the initiation of surgical multicenter trials which can be effectively conducted by local networking. To accomplish a timely recruitment of patients it is necessary to integrate surgical departments outside university hospitals into multicenter trials. With a questionnaire survey of non-university surgical departments in the federal states of Berlin and Brandenburg, interest, experience in clinical trials and structural conditions in these departments were evaluated. Based on the results of this survey the possibilities to integrate non-university surgical departments into multicenter trials and how a high recruitment of patients can be motivated will be discussed in this article.The demand for high quality evidence-based surgical treatment in Germany and awareness of the poor quality of surgical trials highlight the basic necessity of randomized controlled trials. In six surgical trial centers a professional infrastructure for surgical trials is in the process of being established since 2006.The aim is the initiation of surgical multicenter trials which can be effectively conducted by local networking. To accomplish a timely recruitment of patients it is necessary to integrate surgical departments outside university hospitals into multicenter trials. With a questionnaire survey of non-university surgical departments in the federal states of Berlin and Brandenburg, interest, experience in clinical trials and structural conditions in these departments were evaluated. Based on the results of this survey the possibilities to integrate non-university surgical departments into multicenter trials and how a high recruitment of patients can be motivated will be discussed in this article.