[Laparoscopic Heller Myotomy in the Treatment of Achalasia]. / Laparoskopische Heller-Myotomie zur Therapie der Achalasie.

BACKGROUND: Achalasia refers to a primary oesophageal motility disorder characterised by the absence of peristalsis and incomplete or complete lack of relaxation of the lower oesophageal sphincter. The cardinal symptom is dysphagia. The therapeutic goal is surgical or interventional repair of the oesophageal outflow tract at the level of the oesophagogastric junction. INDICATION: We present the case of a 24-year-old patient with dysphagia accompanied by regurgitations, odynophagia as well as an unintentional weight loss over two years. METHODS: The video describes the preoperative imaging as well as endoscopic findings and demonstrates the technique of laparoscopic Heller myotomy followed by Dor fundoplication. CONCLUSIONS: Concerning the therapy of classic achalasia, laparoscopic Heller myotomy followed by Dor fundoplication - despite controversies regarding peroral endoscopic myotomy as an alternative therapeutic option - can be considered as an established standard procedure.

Impact of haptic feedback on applied intracorporeal forces using a novel surgical robotic system-a randomized cross-over study with novices in an experimental setup.

BACKGROUND: Most currently used surgical robots have no force feedback; the next generation displays forces visually. A novel single-port robotic surgical system called FLEXMIN has been developed. Through an outer diameter of 38 mm, two instruments are teleoperated from a surgeon's control console including true haptic force feedback. One additional channel incorporates a telescope, another is free for special instrument functions. METHODS: This randomized cross-over study analyzed the effect of haptic feedback on the application of intracorporeal forces. In a standardized experiment setup, the subjects had to draw circles with the surgical robot as gently as possible. The applied forces, the required time spans, and predefined error rates were measured. RESULTS: Without haptic feedback, the maximum forces (median/IQR) were 6.43 N/2.96 N. With haptic feedback, the maximum forces were lower (3.57 N/1.94 N, p < 0.001). Also, the arithmetic means of the force progression (p < 0.001) and their standard deviations (p < 0.001) were lower. Not significant were the shorter durations and lower error rates. No sequence effect of force or duration was detected. No characteristic learning or fatigue curve was observed. CONCLUSIONS: In the experiment setup, the true haptic force feedback can reduce the applied intracorporeal robotic force to one-half when considering the aspects maximum, means, and standard deviation. Other test tasks are needed to validate the influence of force feedback on surgical efficiency and safety.

A Novel Approach for Routinely Assessing Laboratory Sigma Metrics for a Broad Range of Automated Assays.

BACKGROUND: Sigma metrics have been adapted for the clinical laboratory to incorporate observed accuracy, precision, and total error allowed. The higher the Sigma level for a process, the better performance that process has. A limitation of studies assessing Sigma metrics is that they are performed on a small number of well-controlled systems. METHODS: An algorithm was developed to extract QC data and derive the Sigma metric for 115 analytes from sites connected to the QuidelOrtho E-Connectivity® database. The median of these results was then used to derive the Sigma metric for each assay. RESULTS: In this analysis, 79 out of 115 (68.7%) of the assays assessed achieved 6 Sigma or better and 98 out of 115 (85.2%) achieved 5 Sigma or better. CONCLUSIONS: This study has demonstrated a methodology that can be used to condense Sigma metrics from hundreds of analyzers into a single metric of assay quality. Because these analyzers are running in working laboratories from around the world, this analysis can serve as a baseline for understanding the assay performance achieved in the presence of variabilities such as lab-to-lab, instrument-to-instrument, material handling, environmental conditions, and reagent lot. The significant number of assays demonstrating high Sigma levels did so despite this variation. The ability of the methods reported here to include hundreds of analyzers represents a novel approach for assessing Sigma metrics in clinical laboratories.

Detection of adverse events leading to inadvertent injury during laparoscopic cholecystectomy using convolutional neural networks.

Uncontrolled movements of laparoscopic instruments can lead to inadvertent injury of adjacent structures. The risk becomes evident when the dissecting instrument is located outside the field of view of the laparoscopic camera. Technical solutions to ensure patient safety are appreciated. The present work evaluated the feasibility of an automated binary classification of laparoscopic image data using Convolutional Neural Networks (CNN) to determine whether the dissecting instrument is located within the laparoscopic image section. A unique record of images was generated from six laparoscopic cholecystectomies in a surgical training environment to configure and train the CNN. By using a temporary version of the neural network, the annotation of the training image files could be automated and accelerated. A combination of oversampling and selective data augmentation was used to enlarge the fully labeled image data set and prevent loss of accuracy due to imbalanced class volumes. Subsequently the same approach was applied to the comprehensive, fully annotated Cholec80 database. The described process led to the generation of extensive and balanced training image data sets. The performance of the CNN-based binary classifiers was evaluated on separate test records from both databases. On our recorded data, an accuracy of 0.88 with regard to the safety-relevant classification was achieved. The subsequent evaluation on the Cholec80 data set yielded an accuracy of 0.84. The presented results demonstrate the feasibility of a binary classification of laparoscopic image data for the detection of adverse events in a surgical training environment using a specifically configured CNN architecture.

TuThor: an innovative new training model for video-assisted thoracic surgery.

OBJECTIVES: Video-assisted thoracic surgery (VATS) is a complex technique requiring dedicated surgical training. Platforms for such training are scarce and often rely on the use of live animals, which raises ethical concerns. The objective of this study was to develop a box trainer that is dedicated for VATS training and able to reproduce bleeding scenarios. METHODS: The developed Tuebingen Thorax Trainer comprises 5 components that are mounted on a human anatomy-like thoracic cavity containing a porcine organ complex. Any standard thoracoscopic instrument can be used. The organ complex is attached to a perfusion module. We assessed the applicability of the system in four 1-day VATS training courses at the Tuebingen Surgical Training Center. Assessment was performed using a questionnaire handed out to all participants. RESULTS: Forty participants have been trained with the Tuebingen Thorax Trainer at our institution since November 2016. Thirty-five (87.5%) participants stated that the Tuebingen Thorax Trainer is an adequate model for VATS training. The ex vivo organ complex was reported to be realistic with regards to the level of detail and scale (76%). A large proportion of participants (27.5%) were experienced with VATS and reported having performed >50 procedures before taking the training course. CONCLUSIONS: This new training device allows realistic training for VATS procedures. 'Stagnant hydrostatic perfusion' permits simulation of reproducible bleeding scenarios. The device is low in production costs and offers a strong resemblance to the clinical scenario. It reduces the use of animal models and contributes to the efforts in making surgical skills training for VATS more accessible.

Profiling the HER3/PI3K pathway in breast tumors using proximity-directed assays identifies correlations between protein complexes and phosphoproteins.

BACKGROUND: The identification of patients for targeted antineoplastic therapies requires accurate measurement of therapeutic targets and associated signaling complexes. HER3 signaling through heterodimerization is an important growth-promoting mechanism in several tumor types and may be a principal resistance mechanism by which EGFR and HER2 expressing tumors elude targeted therapies. Current methods that can study these interactions are inadequate for formalin-fixed, paraffin-embedded (FFPE) tumor samples. METHODOLOGY AND PRINCIPAL FINDINGS: Herein, we describe a panel of proximity-directed assays capable of measuring protein-interactions and phosphorylation in FFPE samples in the HER3/PI3K/Akt pathway and examine the capability of these assays to inform on the functional state of the pathway. We used FFPE breast cancer cell line and tumor models for this study. In breast cancer cell lines we observe both ligand-dependent and independent activation of the pathway and strong correlations between measured activation of key analytes. When selected cell lines are treated with HER2 inhibitors, we not only observe the expected molecular effects based on mechanism of action knowledge, but also novel effects of HER2 inhibition on key targets in the HER receptor pathway. Significantly, in a xenograft model of delayed tumor fixation, HER3 phosphorylation is unstable, while alternate measures of pathway activation, such as formation of the HER3PI3K complex is preserved. Measurements in breast tumor samples showed correlations between HER3 phosphorylation and receptor interactions, obviating the need to use phosphorylation as a surrogate for HER3 activation. SIGNIFICANCE: This assay system is capable of quantitatively measuring therapeutically relevant responses and enables molecular profiling of receptor networks in both preclinical and tumor models.

Cavity ring-down spectroscopy measurement of single aerosol particle extinction. II. Extinction of light by an aerosol particle in an optical cavity excited by a cw laser.

The authors present an analytical derivation of the scattered power from a spherical, homogeneous, nonabsorbing particle in a plane standing wave. The scattered power changes significantly with the position of the particle with respect to the peaks and nodes of the standing wave, even for particles whose diameters are many times the wavelength of the light. The analysis is applicable to continuous-wave cavity ring-down spectroscopy on aerosol particles, and the structure of the standing wave is expected to affect both the measured ring-down time and the shape of the ring-down trace. The dependence of the extinction on the phase of the standing wave at the location of the particle is captured in a parameter zeta which connects the current treatment to standard Mie scattering theory. Methods for calculating zeta are presented.

Cavity ring-down spectroscopy measurements of single aerosol particle extinction. I. The effect of position of a particle within the laser beam on extinction.

A continuous wave distributed feedback diode laser operating in the near infrared at wavelengths close to 1650 nm has been used to measure the extinction of light by single aerosol particles. The technique of optical feedback cavity ring-down spectroscopy (CRDS) was used for measurement of CRDS events at a repetition rate of 1.25 kHz. This very high repetition rate enabled multiple measurements of the extinction of light by single aerosol particles for the first time and demonstrated the dependence of light scattering on the position of a particle within the laser beam. A model is proposed to explain quantitatively this phenomenon. The minimum detectable dimensionless extinction coefficient epsilonmin was determined to be 3x10(-6). Extinction values obtained for single spherical polymer beads from a monodisperse sample of particles of diameter of 4 microm are in near-quantitative agreement with the values calculated by the Mie scattering theory. The deviations from the Mie theory expected for measurement of extinction by CRDS using a continuous wave laser are discussed in the companion paper.

Dissociation channels of the 1-buten-2-yl radical and its photolytic precursor 2-bromo-1-butene.

The work presented here is the first in a series of studies that use a molecular beam scattering technique to investigate the unimolecular reaction dynamics of C(4)H(7) radical isomers. Photodissociation of the halogenated precursor 2-bromo-1-butene at 193 nm under collisionless conditions produced 1-buten-2-yl radicals with a range of internal energies spanning the predicted barriers to the unimolecular reaction channels of the radical. Resolving the velocities of the stable C(4)H(7) radicals, as well as those of the products, allows for the identification of the energetic onset of each dissociation channel. The data show that radicals with at least 30.7 +/- 2 kcal/mol of internal energy underwent C-C fission to form allene + methyl, and radicals with at least 36.7 +/- 4 kcal/mol of internal energy underwent C-H fission to form H + 1-butyne and H + 1,2-butadiene; both of these observed barriers agree well with the G3//B3LYP calculations of Miller. HBr elimination from the parent molecule was observed, producing vibrationally excited 1-butyne and 1,2-butadiene. In the subsequent dissociation of these C(4)H(6) isomers, the major channel was C-C fission to form propargyl + methyl, and there is also evidence of at least one of the possible H + C(4)H(5) channels. A minor C-Br fission channel produces 1-buten-2-yl radicals in an excited electronic state and with low kinetic energy; these radicals exhibit markedly different dissociation dynamics than do the radicals produced in their ground electronic state.

Dissociation of the ground state vinoxy radical and its photolytic precursor chloroacetaldehyde: electronic nonadiabaticity and the suppression of the H+ketene channel.

This work is a study of the competition between the two unimolecular reaction channels available to the vinoxy radical (CH(2)CHO), C-H fission to form H+ketene, and isomerization to the acetyl radical (CH(3)CO) followed by C-C fission to form CH(3) + CO. Chloroacetaldehyde (CH(2)ClCHO) was used as a photolytic precursor to the vinoxy radical in its ground state; photodissociation of chloroacetaldehyde at 193 nm produces vinoxy radicals with internal energies spanning the G3//B3LYP calculated barriers to the two available unimolecular reaction channels. The onset of the CH(3) + CO channel, via isomerization to the acetyl radical, was found to occur at an internal energy of 41 +/- 2 kcal/mol, agreeing well with our calculated isomerization barrier of 40.8 kcal/mol. Branching to the H+ketene channel was too small to be detected; we conclude that the branching to the H+ketene channel must be at least a factor of 200 lower than what is predicted by a RRKM analysis based on our electronic structure calculations. This dramatic result may be explained in part by the presence of a conical intersection at planar geometries along the reaction coordinate leading to H+ketene, which results in electronically nonadiabatic recrossing of the transition state.