Abstracts - Chirurgie Kongress

interested whether AM donor pretreatment affects organ quality and function of livers procured for
preservation and transplantation.
Methods: Donor rats were pretreated with AM (5mg/kg body weight) 10min before flushout of the liver
with 4°C cold HTK solution (n=8). Livers were then stored for 24h at 4°C before ex situ reperfusion with
37°C Krebs Henseleit solution for 60min in a non-recirculating system. At the end of reperfusion tissue
samples were taken for histology and Western blot analysis. Animals with vehicle only (0.9% NaCl)
served as ischemic/reperfusion (I/R) controls (n=8). Additionally livers of untreated animals (n=8) not
subjected to 24h cold ischemia served as sham controls.
Results: AM pretreatment effectively attenuated lipid peroxidation, stress protein expression and
apoptotic cell death. This was indicated by an AM-mediated reduction of malondialdehyde, heme oxygenase-1
and caspase-3 activation. However, AM treatment also induced mitochondrial damage and
hepatocellular excretory dysfunction, as indicated by a significantly increased GLDH concentration in
the effluate and a decreased bile production.
Conclusion: AM donor pretreatment exerts anti-oxidative actions in liver preservation and reperfusion.
However, this protective AM action is counteracted by an in-duction of mitochondrial damage and hepatocellular
dysfunction. Accordingly, AM pretreat-ment of donors for anti-arrhythmic therapy should
be performed with caution.
48.6
Novel lung fixation technique by controlled vascular perfusion for stereological analysis in a large
animal model
O. Loup, A. Kadner, K. Purkabiri, H. Jenni, B. Eberle, T. Carrel, S. Trachsel (Bern)
Objective: Stereology is an excellent method for quantitative pulmonary structural analysis. However,
adequate lung fixation is an extremely important requirement to avoid alterations in pulmonary tissue,
dimensions and structural details. Here we present our vascular lung perfusion method for pulmonary
fixation under defined perfusion and airway pressure in a large animal model.
Methods: 20 piglets (30+/-3kg) were heparinized. After median sternotomy, the main pulmonary artery
was cannulated. For isolated perfusion of the left lung, the entire right lung hilus was ligated. Ventilation
was stopped and a continuous positive pressure of 12 cm H2O applied during fixation. Lung
perfusion was performed by a roller pump. First, blood was eliminated by perfusion with 4l of 0.9%
saline solution. Subsequently, the fixative, containing 1.5% Paraformaldehyde; 1.5% Glutaraldehyde in
0.15M HEPES, was perfused and recycled from left atrial venting. Pulmonary artery perfusion pressure
was continuously measured. After completion of perfusion, lungs were removed and externally fixed
for stereological analysis.
Results: Perfusion of the lungs was accomplished by a flow rate of 0.5 – 0.7 l/min with a total perfusion
time of 13‘30 min. The mean pressure during saline flow was 17.1 +/- 4.4 mmHg, and mean perfusion
pressure during lung fixation was 20 +/- 5.2 mmHg. Subsequent analysis of the lung specimens
revealed preserved tissue structure and morphology.
Conclusion: The present technique allows a novel valuable and reproducible fixation method for stereological
lung analysis in a large animal model. Fixation with physiological pressure controlled perfusion
results in preserved pulmonary tissue, dimensions and structural details.
48.7
For a better understanding of surgical glues
B. Perrin 1 , M. Dupeux 2 , M. van Steenbergue 1 , L. von Segesser 1 ( 1 Lausanne, 2 Grenoble/FR)
Objective: Adhesion of surgical glues is finally disapointing. The blister test is developed by industrial
engineering and is very convenient to measure adhesion energy. We adapted this test to surgical conditions.
Results give important information for a better understanding of adhesion of surgical glues and
allow to think about a way to improve it.
Methods: Samples are composed of two circular layers of equine pericardium glued by the surgical
sealant of interest. Comparative adhesion testing was carried out in 37 paired calf pericardium samples
bonded with surgical cyanoacrylate glue, and on 4 samples with industrial cyanoacrylate glue.
Samples have been observed on electronic microscopy.
Results: Adhesion energy of surgical glues in surgical conditions is 1.16 J/m 2 ± 1,69. Usual adhesion
energy for a standart industrial glue is around 10 to 100 J/m 2 . Adhesion energy of industrial glues in
surgical conditions is comparable to adhesion energy obtained with surgical glues. Observation of
delaminations on samples with electronic microscopy showed that it happen at the interface between
the glue and a pericardial layer. It means that this adhesion is adhesive but not cohesive.
Conclusion: The poor mechanical behaviour of surgical glues is not due their properties but due to
surgical conditions and specific nature of the biological support.
To improve adhesion in the surgical field, we need to concentrate in the way to obtain a cohesive adhesion
with a better cohesion between interfaces by modifying conditions of constitution of the join. The
industrial field of glues knew a fantastic evolution these last decades with the study and utilisation of
the surface preparation and this should be applied in the surgical field.
General Surgery – Posters 57
57.1
Intraoperative Neurostimulation des Nervus laryngeus recurrens: Vergleich zwischen Tubusklebe-
und intralaryngealer Nadelelektrode
B. Huettenmoser, W. Schweizer (Schaffhausen)
Objective: Das intraoperative Monitoring des Nervus laryngeus recurrens hat sich bei Schilddrüsen-
und Nebenschilddrüsenoperationen bewährt.Die Ableitung des Impulses kann über eine präoperativ
auf den Trachealtubus geklebte Elektrode oder durch intraoperativ in die intrinsische Laryngealmuskulatur
gesteckte Nadelelektroden abgeleitet werden. Mit dieser Studie vergleichen wir die Zuverlässigkeit
beider Ableitungen. Seit Mai 2006 verwenden wir eine neue Klebeelektrode (Invotec ® Fa. Novimed).
Methods: 41 Patienten mit 58 zu stimulierenden Rekurrensnerven(„nerves at risc“)wurden zwischen
Mai 2004 und Januar 2009 operiert. Bei 33 Patienten wurde die Nadel und die Tubuselektrode
verwendet,bei 7 Patienten nur die (neue)Tubuselektrode und bei einem Patienten konnte der Nerv
nicht identifiziert werden.
Die Reizschwellenstromstärke (RST), das heisst jene Nervenstimulationsstärke, bei der ein akustisches
Signal gerade noch hörbar ist, wurde gemessen.
Results: Mit der Nadel konnte bei 33 von 33 Patienten (100%) abgeleitet werden. Die RST betrug im
Schnitt 0.4 mA (0.1-1.1). Mit der alten Tubusklebeelektrode konnte bei 15 von 18 Patienten abgeleitet
werden (83.3%). Die RST betrug 0.7 mA (0.2 – 1.5). In drei Fällen konnte mit der Nadel aber nicht mit
der Elektrode abgeleitet werden. Bei 21 von 22 Patienten konnte mit der neuen Klebeelektrode abgeleitet
werden (95.5 %).Die RST betrug 0.5 mA (0.2 – 1).Bei einem Patienten wurde der Nerv nicht
identifiziert.
Conclusion: Das kontinuierliche intraoperative Monitoring des N. laryngeus recurrens mittels Nervenstimulation
ist einfach, zuverlässig und atraumatisch. Mit der neuen Tubus-Klebeelektrode konnte, im
Gegensatz zum Vorgängermodell, ausser in einem Fall zuverlässig abgeleitet werden. Ihre Sensitivität
ist nahe an jener der Nadelelektrode, mit dem Vorteil, dass die Tubuselektrode atraumatisch platziert
wird. Auf die Verwendung der invasiveren Nadelelektrode kann dank der neuen Invotec ® Tubuselektrode
in den meisten Fällen verzichtet werden.
57.2
Fractured posterior malleolus in ankle fractures – is a CT scan of benefit for surgical strategy?
J. Forberger, S. Fleischmann, M. Dietrich, A. Platz (Zürich)
Objective: The importance of stable anatomical reconstruction of the joint surface in ankle fractures is
well described in literature. The indication and technique for surgical intervention are still the subject of
debate. For these the analysis of the posterior tibial fragment is very important.
Few data are available on the radiological interpretation of the posterior malleolus in ankle fractures.
The objective of this analysis is to evaluate the differences in radiological interpretation of plain X-Ray
and CT scan and the consequences of those for surgical strategy.
Methods: From January 2006 to December 2007 all patients with posterior displaced tibial fragment
in ankle fractures were consecutively included into this single institution study and underwent a plain
X ray and a CT scan of the ankle. Three individual measurement of the fragment size were taken by
two independent investigators. Each examiner assessed the fragment size in plain radiographs (lateral
view) and in two CT plans (lateral and axial) following a selected reading point. Measurements
were obtained using a digital ruler. The existence of intermediary fragments was investigated in both
examinations.
Results: During the time period 40 Patients (29 female, 11 male) were consecutively included into
the study. According to the Haraguchi classification of the posterior malleolus there were 14 fractures
classified as type I, 23 were classified as type II and 3 as type III. Intermediary fragments were poorly
detected in radiographs (8 versus 11 by the investigators) but were seen in CT scans in 36 cases by
both examiner (p