Numerical assessment of induced electric fields in a worker's hand with commonly used metallic implants under exposure to low frequency magnetic fields.

The European Union's Workers' Directive 2013/35/EU on the minimum health and safety requirements regarding the exposure of workers to electromagnetic fields specifies action levels (ALs) for external electric and magnetic fields, which should protect against induced tissue-internal electric field strengthEiabove the exposure limit values, the latter being defined in order to prevent tissue stimulation at low frequencies. However, although 2013/35/EU explicitly calls for the protection of 'workers at particular risk' (including workers with metallic implants), the AL specified in the Directive have been derived under the assumption that there are no metallic parts present inside the body. Therefore, in the present work, we analysed the situation of a worker's hand and forearm bearing metallic implants (Herbert screw and volar radius plate) used for osteosynthesis after the most common bone fractures of the hand/forearm, exposed to low frequency magnetic fields. The uniform exposure of the whole hand and forearm as well as the exposure to a specific and widely used device, a deactivator for single-use labels of acousto-magnetic electronic article surveillance systems, were considered based on numerical computations using a high-resolution anatomical hand and forearm model. The results obtained indicated that the maximum induced electric field strength averaged in a volume of 2 mm × 2 mm × 2 mm cube was higher in the presence of the metallic implants by a factor of up to 4.2 for bone tissue and 2.3 for soft tissue compared with the case without an implant. Hence, it is obvious that the local induced electric field strengths may be substantially increased by the implants. The extent of this increase, however, is highly dependent on the implant's position inside the body, the implant's geometry, and the field distribution and orientation with respect to the anatomical structure and the implant.

Development and assessment of a loop ligation simulator for laparoscopic appendectomy.

OBJECTIVE: Loop ligation of the appendix is a challenging surgical skill and well suited to be trained in a simulator. We aimed to develop an affordable and easy-to-build simulator and test its training effect. DESIGN AND PARTICIPANTS: Different materials were tested, and the best training modality was identified by researching the literature. The developed simulator training was tested on 20 surgical novices. RESULTS: A video was produced including an instruction on how to build the simulator and a step-by-step tuition on how to ligate the appendix. The Peyton approach was utilized to guide learners. Training with the simulator leads to reliable skill acquisition. All participants improved significantly in completing the task successfully during the structured learning. CONCLUSION: We succeeded in developing a simulator for loop ligation of the appendix during laparoscopic appendectomy. Participants significantly improve in handling the loops. The transferability of the skill learned during simulation to the operating room will be subject of a follow-up study.

Surgical simulation of hypospadias repair - High-fidelity, reproducible and affordable animal tissue model.

INTRODUCTION: Teaching methods in hypospadias repair are still traditional. Available simulators often lack authenticity in terms of haptic feedback and realistic tissue handling. OBJECTIVE: Our aim was to develop a high-fidelity, easily reproducible, and affordable animal tissue model for the advanced surgical simulation of hypospadias repair with realistic haptic feedback and tissue handling. MATERIAL AND METHODS: A regular-sized chicken leg and a lamb tenderloin are used to assess the feasibility of simulating hypospadias correction by using the example of a Snodgrass Tubularized Incised Plate-Repair. The model preparation is incorporated into the training process. RESULTS: A detailed description of the high-fidelity model is provided. All steps of a hypospadias repair can be trained while providing realistic anatomy, adequate size, and multilayer tissue properties. Haptic conditions highly resemble human tissue properties. Fine tissue handling corresponds to intraoperative conditions. Limitations to this surgical model apply as in other animal tissue models. CONCLUSION: We developed a high-fidelity, easily reproducible, and affordable hypospadias animal tissue model. Due to the multilayer animal tissue properties, this model provides realistic haptic feedback and thus an inexpensive and reproducible model for hypospadias simulation. External validation is mandatory prior to implementation into urological training.

Surgical Simulation of Posterior Sagittal Anorectoplasty for Rectovestibular Fistula: Low-Cost High-Fidelity Animal-Tissue Model.

PURPOSE: To provide a high-fidelity, animal tissue-based model for the advanced surgical simulation of a Posterior Sagittal Anorectoplasty (PSARP) for rectovestibular fistula in anorectal malformation (ARM). MATERIALS AND METHODS: A chicken cadaver was used to assess the feasibility of simulating a PSARP for rectovestibular fistula in ARM. No modification was required to implement the surgical simulation. RESULTS: A detailed description of the high-fidelity surgical simulation model is provided. The PSARP can be simulated while providing realistic anatomy (e.g. common wall between rectovestibular fistula and vagina), adequate rectal size, location and placement of the rectovestibular fistula, and proximity to the vagina. Haptic conditions of the tissue resemble human tissue and operative conditions as well. DISCUSSION: Concerning the decreased exposure of index cases of pediatric surgical trainees and pediatric surgeons in practice, simulation-based training can provide means to acquire or maintain the necessary skills to perform complex surgical procedures [1-5] Surgical simulation models for ARM are limited. Few low-cost trainers are available with predominant artificial and mostly unrealistic tissue [6-8] Animal models have the advantage of realistic multilayer tissue haptic feedback [6]. CONCLUSION: We provide a low-cost, high-fidelity model for correcting a rectovestibular fistula in a child with ARM, a complex operative procedure with low incidence but high-stake outcomes. The described tissue model utilizing the chicken cloaca anatomy provides a high-fidelity model for operative correction of rectovestibular ARM. For simulation purposes in the treatment of ARM, this model appears to be promising in terms of providing realistic pathology and haptic feedback in pediatric dimensions. LEVEL OF EVIDENCE: V.

Successful Treatment of a Single Giant Renal Cyst in a Newborn with Drainage and Sclerotherapy.

Simple renal cysts are a scarce entity in pediatric patients and their etiology is unknown in most cases. Usually, they are monitored with ultrasound and regular follow-up of renal function. Surgical treatment is rarely indicated. We report the case of a newborn with a single giant renal cyst that could be treated successfully with drainage and sclerotherapy. Single giant renal cysts require careful investigation and monitoring. In cysts without communication to the pelvico-caliceal system, sclerotherapy by instillation of doxycycline is a therapeutic option.

Global Irradiation in Children Treated for Hydrocephalus and Its Change over Time-A Single Institutional Analysis.

Radiation exposure early in life is associated with greater incidences of malignancy. Our goal was to quantify radiation exposure in shunt-treated hydrocephalus patients and study changes in the diagnostic modalities used. A single-center, retrospective analysis was performed, and 41 children treated for hydrocephalus using an adjustable ventriculoperitoneal shunt were identified. Diagnostics associated with hydrocephalus and other comorbidities were analyzed and radiation exposure was calculated. During 330.09 total shunt years, patients were exposed to a mean hydrocephalus-associated radiation dose of 3.93 mSv (range: 0-24.38 mSv), which amounted to a mean rate of 0.49 mSv per shunt year, respectively. Radiation exposure was greatest after shunt insertion in the first year of life. A continuous change from CT scans to MRIs could be seen over the study period, such that patients who underwent shunt insertion after 2017 were not exposed to additional hydrocephalus-associated radiation during their first year of life. Nevertheless, our patients, and a few individuals especially, seemed to be at higher risk for radiation sequelae. Our results suggest that CT scans should be substituted with MRIs, which decrease overall radiation exposure and can lead to zero additional radiation exposure during the first year of life after shunt insertion.