Quantification of electrosurgery-related critical events during laparoscopic cholecystectomy – a prospective experimental study among surgical novices

Uncontrolled movement of instruments in laparoscopic surgery can lead to inadvertent tissue damage, particularly when the dissecting or electrosurgical instrument is located outside the field of view of the laparoscopic camera. The incidence and relevance of such events are currently unknown. The present work aims to identify and quantify potentially dangerous situations using the example of laparoscopic cholecystectomy (LC). Twenty-four final year medical students were prompted to each perform four consecutive LC attempts on a well-established box trainer in a surgical training environment following a standardized protocol in a porcine model. The following situation was defined as a critical event (CE): the dissecting instrument was inadvertently located outside the laparoscopic camera’s field of view. Simultaneous activation of the electrosurgical unit was defined as a highly critical event (hCE). Primary endpoint was the incidence of CEs. While performing 96 LCs, 2895 CEs were observed. Of these, 1059 (36.6%) were hCEs. The median number of CEs per LC was 20.5 (range: 1–125; IQR: 33) and the median number of hCEs per LC was 8.0 (range: 0–54, IQR: 10). Mean total operation time was 34.7 min (range: 15.6–62.5 min, IQR: 14.3 min). Our study demonstrates the significance of CEs as a potential risk factor for collateral damage during LC. Further studies are needed to investigate the occurrence of CE in clinical practice, not just for laparoscopic cholecystectomy but also for other procedures. Systematic training of future surgeons as well as technical solutions address this safety issue

MEASUREMENT OF THE FREE-SURFACE ELEVATION FOR FLOWS IN COMPLEX TOPOGRAPHY USING PHOTOGRAMMETRY

Predicting the flow in rivers is an important concern regarding potential damages induced by floods. Numerical models, if they can be used as predicting tool, need to be tested to assess their reliability. This can be done by comparing their results to field measurements or experimental data. However, such comparisons are often not easy to interpret since the differences can come from a multitude of causes. Therefore, it is preferred to use well-documented experimental data obtained in a well-controlled environment. As regards water level measurements, several methods exist. Gauges provide information on a small area (point measurement method). Other techniques (imagery based analysis) such as filming through a side panel provide the water level along the considered axis but require an optical access to the area which is not always possible. This paper investigates the use of photogrammetry to measure the water level. Photogrammetry is a non-intrusive method allowing for the capture of the water level over a large area in one run of the experiment. However, its application still presents numerous challenges. The work presented here compares the results obtained using photogrammetry to other more classical measurement methods on the case of a steady flow in an arbitrary topography built in concrete. The results show good agreement between both measurement techniques and highlight the capabilities of using photogrammetry in the laboratory

The morphology proteins Mdm12/Mmm1 function in the major β-barrel assembly pathway of mitochondria

The β-barrel proteins of mitochondria are synthesized on cytosolic ribosomes. The proteins are imported by the translocase of the outer membrane (TOM) and the sorting and assembly machinery (SAM). It has been assumed that the SAM(core) complex with the subunits Sam35, Sam37 and Sam50 represents the last import stage common to all β-barrel proteins, followed by splitting in a Tom40-specific route and a route for other β-barrel proteins. We have identified new components of the β-barrel assembly machinery and show that the major β-barrel pathway extends beyond SAM(core). Mdm12/Mmm1 function after SAM(core) yet before splitting of the major pathway. Mdm12/Mmm1 have been known for their role in maintenance of mitochondrial morphology but we reveal assembly of β-barrel proteins as their primary function. Moreover, Mdm10, which functions in the Tom40-specific route, can associate with SAM(core) as well as Mdm12/Mmm1 to form distinct assembly complexes, indicating a dynamic exchange between the machineries governing mitochondrial β-barrel assembly. We conclude that assembly of mitochondrial β-barrel proteins represents a major function of the morphology proteins Mdm12/Mmm1