Background During laparoscopy, the abdominal cavity is insufflated with carbon dioxide (CO2) that could become contaminated with viruses and surgical smoke. Medical staff is potentially exposed when this gas leaks into the operating room through the instruments and past trocar valves. No detailed studies currently exist that have quantified these leakage pathways. Therefore, the goal of this study was to quantify the gas leakages through trocars and instruments, during minimally invasive procedures. Methods A model of the surgical environment was created, consisting of a rigid container with an interface for airtight clamping of laparoscopic equipment such as trocars and surgical instruments. The model was insufflated to 15 mm Hg using a pressure generator and a pneumotachograph measured the equipment gas leak. A protocol of several use cases was designed to simulate the motions and forces the surgeon exerts on the trocar during surgery. Results Twenty-three individual trocars and twenty-six laparoscopic instruments were measured for leakage under the different conditions of the protocol. Trocar leakages varied between 0 L/min and more than 30 L/min, the instruments revealed a range of leakages between 0 L/min and 5.5 L/min. The results showed that leakage performance varied widely between trocars and instruments and that the performance and location of the valves influenced trocar leakage. Conclusions We propose trocar redesigns to overcome specific causes of gas leaks. Moreover, an international testing standard for CO2 leakage for all new trocars and instruments is needed so surgical teams can avoid this potential health hazard when selecting new equipment.

Objective: To develop a realistic simulation model for laparotomy-assisted fetoscopic spina bifida aperta (SBa) surgery, to be used for training purposes and preoperative planning. Methods:The predefined general requirement was a realistic model of an exteriorized uterus, allowing all neurosurgical steps of the intervention. The uterus was modelled using ultrasound and MRI images of a 25 weeks' gravid uterus, consisting of flexible polyurethane foam coated with pigmented silicone. The fetal model, contained an opening on the dorsal side for a customizable spinal insert with all the aspects of a SBa, including a cele, placode, and myofascial and skin layer. The model was assessed in a series of validation experiments.Results: Production costs are low, uterus and fetus are reusable. Placental localization and the level and size of the spinal defect are adjustable, enabling casespecific adaptations. All aspects of the simulator were scored close to realistic or higher for both appearance and functional capacities. Conclusions:This innovative model provides an excellent training opportunity for centers that are starting a fetoscopic SBa repair program. It is the first simulation model with adjustable spinal defect and placental localisation. Further objective validation is required, but the potential for using this model in preoperative planning is promising. Key points What is already known about this topic?� Fetal surgery is a well-known option for the treatment of myelomeningocele (MMC), yet the downside of the open procedure is its invasiveness. Fetoscopic surgery may be an option to overcome at least part of these complications but comes with a long learning curve.� Simulation models may prove themselves effective in shortening these learning curves; however, for MMC, the current models are either expensive, animal based, or low fidelity.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Background Abdominal compliance describes the ease of expansion of the abdominal cavity. Several studies highlighted the importance of monitoring abdominal compliance (Cab) during the creation of laparoscopic workspace to individualize the insufflation pressure. The lack of validated clinical monitoring tools for abdominal compliance prevents accurate tailoring of insufflation pressure. Oscillometry, also known as the forced oscillation technique (FOT), is currently used to measure respiratory mechanics and has the potential to be adapted for monitoring abdominal compliance. This study aimed to define, develop and evaluate a novel approach which can monitor abdominal compliance during laparoscopy using endoscopic oscillometry. Materials and methods Endoscopic oscillometry was evaluated in a porcine model for laparoscopy. A custom-built insufflator was developed for applying an oscillatory pressure signal superimposed onto a mean intra-abdominal pressure. This insufflator was used to measure the abdominal compliance at insufflation pressures ranging from 5 to 20 hPa (3.75 to 15 mmHg). The measurements were compared to the static abdominal compliance, which was measured simultaneously with computed tomography imaging. Results Endoscopic oscillometry recordings and CT images were obtained in 10 subjects, resulting in 76 measurement pairs for analysis. The measured dynamic Cab ranged between 0.0216 and 0.261 L/hPa while the static Cab based on the CT imaging ranged between 0.0318 and 0.364 L/hPa. The correlation showed a polynomial relation and the adjusted R-squared was 97.1%. Conclusions Endoscopic oscillometry can be used to monitor changes in abdominal compliance during laparoscopic surgery, which was demonstrated in this study with a comparison with CT imaging in a porcine laparoscopy model. Use of this technology to personalize the insufflation pressure could reduce the risk of applying excessive pressure and limit the drawbacks of insufflation.