Comparison of capabilities and limitations of endoscopes in endoscopic ear surgeries using 3D printed models.

PURPOSE: Endoscopic ear surgery has become a popular operative approach to treat middle ear diseases. Surgeons use either 0° or 30° endoscopes worldwide. The main aim of the work was to compare the properties of these two types of endoscopes. MATERIAL AND METHODS: Since this type of evaluation is hard to perform in vivo during the actual surgery, we designed 3D printed temporal bone models with different levels of complexity. The evaluation of endoscopes was based on image analysis or visibility of anatomical structures. RESULTS: The results show that a 30° endoscope offers a view of lateral walls from 4 mm distance, contrary to a 0° endoscope which cannot see lateral walls from this distance at all. On the other hand, visible area of the anterior wall is up to 40 % larger using 0° endoscope, compared to 30° endoscope. Angled endoscope distorts the picture and leads to the deterioration of the image. At commonly used distances above 5 mm from middle ear structures, resolution and image distortion is comparable between both endoscopes. CONCLUSIONS: Our results do not offer a definitive opinion on which endoscope is better for ear surgery. Both types of endoscopes have advantages and disadvantages, and the choice depends on the surgeon's personal preference and on the type of planned procedure.

Newly Designed 3D-Printed Sonication Test Cell Optimized for In Vitro Sonication Experiments.

OBJECTIVE: Precise control over the ultrasound field parameters experienced by biological samples during sonication experiments in vitro may be quite challenging. The main goal of this work was to outline an approach to construction of sonication test cells that would minimize the interaction between the test cells and ultrasound. METHODS: Optimal dimensions of the test cell were determined through measurements conducted in a water sonication tank using 3D-printed test objects. The offset of local acoustic intensity variability inside the sonication test cell was set to value of ±50% of the reference value (i.e., local acoustic intensity measured at last axial maximum in the free-field condition). The cytotoxicity of several materials used for 3D printing was determined using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. RESULTS: The sonication test cells were 3D printed from polylactic acid material, which was not toxic to the cells. Silicone membrane HT-6240, which was used to construct the bottom of the test cell, was found to reduce ultrasound energy minimally. Final ultrasound profiles inside the sonication test cells indicated the desired variability of local acoustic intensity. The cell viability in our sonication test cell was comparable to that of commercial culture plates with bottoms constructed with silicone membrane. CONCLUSION: An approach to construction of sonication test cells minimizing the interaction of the test cell and ultrasound has been outlined.

Hybrid esophagectomy for oesophageal cancer: long-term results. A single-centre experience.

INTRODUCTION: The authors report long-term outcomes in patients who received neoadjuvant chemoradiotherapy and consequently underwent hybrid oesophagectomy for oesophageal cancer (OC). AIM: To evaluate long-term outcomes in patients suffering from OC, who underwent hybrid oesophagectomy. MATERIAL AND METHODS: Our cohort consisted of patients suffering from OC, who received neoadjuvant chemoradiotherapy. Hybrid esophagectomy was performed 8-10 weeks after oncological treatment. RESULTS: Ninety-four patients underwent surgery for OC from 2011 to 2015. Histology revealed adenocarcinoma in 60.6%, squamous cell carcinoma (SCC) in 36.2%, and other type of cancer in 3.2%. Seventy-three (77.7%) patients with advanced stage (T3-4, N0-2, M0) were indicated to receive neoadjuvant chemoradiotherapy (nCRT). Trans-hiatal hybrid oesophagectomy was performed in 83 (88.3%) patients. Transthoracic hybrid oesophagectomy was performed in 11 (11.7%) patients. Histology of the resected specimens of 18 (24.7%) patients did not reveal OC, i.e. pathological complete response (pCR). In our cohort, we proved an association between occurrence of pCR and age as well as disease-free survival (DFS). The patients who presented with pCR were significantly younger - below 60 years of age (p = 0.017). They also showed significantly higher mean DFS (p = 0.004). CONCLUSIONS: Combined oesophagectomy with neoadjuvant chemoradiotherapy results in a better long-term outcome in patients suffering from oesophageal cancer. In our set of patients who underwent hybrid esophagectomy, satisfactory short-term and especially long-term results of surgical treatment for oesophageal cancer were observed.

Far field during sonication experiments in vitro - Is it really far enough?

In many in vitro experiments studying ultrasound bioeffects the sonicated samples are placed to far field with intention of exposing them to as uniform ultrasound field as possible. The main aim of this work is to assess whether the sonicated samples really experience what they are believed to. Also we would like to suggest basic rules for construction of sonication vessels. We used 3.5 MHz and 7 MHz ultrasound transducers for measurements. We measured ultrasound field inside and behind common culture plates and special 3D printed plates placed to last axial maximum in water sonication tank with use of a needle hydrophone. Our results show that even though the sonication vessels with sonicated samples are placed into far field, the sonicated samples are actually exposed to some kind of a near field pattern which develops due to the interaction between ultrasound and well of culture plate. The variability of local acoustic intensity can reach up to several hundreds of percent. Our results are also supported by theoretical calculation and software for simulation of ultrasound fields. Even though the sonicated samples may have actually been exposed to some kind of near field pattern in many past studies, the whole phenomenon of creation of near field pattern can be controlled to some extent for future studies. Thus, we suggest that the sonication vessel should always be designed for particular ultrasound transducer.

Therapeutic ultrasound experiments in vitro: Review of factors influencing outcomes and reproducibility.

Current in vitro sonication experiments show immense variability in experimental set-ups and methods used. As a result, there is uncertainty in the ultrasound field parameters experienced by sonicated samples, poor reproducibility of these experiments and thus reduced scientific value of the results obtained. The scope of this narrative review is to briefly describe mechanisms of action of ultrasound, list the most frequently used experimental set-ups and focus on a description of factors influencing the outcomes and reproducibility of these experiments. The factors assessed include: proper reporting of ultrasound exposure parameters, experimental geometry, coupling medium quality, influence of culture vessels, formation of standing waves, motion/rotation of the sonicated sample and the characteristics of the sample itself. In the discussion we describe pros and cons of particular exposure geometries and factors, and make a few recommendations as to how to increase the reproducibility and validity of the experiments performed.