The non-biological simulator with the ability to regulate the position of the kidney and bone landmarks: use for training puncture access in percutaneous nephrolithotripsy

Introduction. The non-biological simulators presented in the literature are far from the real human anatomy and are primarily aimed at developing the skill of the pyelocalyceal system (PCS) puncture without the possibility of imitating various intraoperative scenarios.Purpose of the study. To describe the manufacturing and initial testing of the ultrasound-guided PCS puncture simulator with arbitrary placement of bone landmarks and a kidney model, along with the use of a retrograde view during PCS puncture.Materials and methods. This study included training for 5 resident and 2 urologists. Each participant performed the puncture 5 times using an 18-gauge ultrasound-guided needle. A comparison was made between the number of attempts to form access, the duration of the puncture and its correctness (puncture into the small calyx through the papilla), as well as the correctness of determining the target calyx. The trajectory of the needle was retrogradely assessed using a semi-rigid ureteroscope, and the anatomical identification of the selected calyx was assessed using our mobile application.Results. The total number of attempts was 49 and 14 among residents and urologists, respectively. The average duration of the puncture step was 25.2 and 12.0 seconds. In 9/25 cases, residents were able to correctly analyze visual ultrasound information to determine the target calyx. When a contrast agent was injected into the PCS after 63 punctures, no contrast leakage was found.Conclusion. The proposed PCS puncture simulator allows to develop to develop all the necessary skills for cost-effective training of young urologists in the technique of percutaneous access

Virtual reality simulator for developing spatial skills during retrograde intrarenal pyeloscopy

Introduction. Currently, several virtual reality (VR) simulators have been described for the upper urinary tract stone surgery skill development, including retrograde or antegrade nephroscopy. However, their high cost and the lack of a detailed reconstruction of the intraluminal pelvicalyceal system (PCS) appearance limit their implementation into educational process and clinical practice.Objectives. To develop the approach for VR-reconstruction of the intraluminal appearance of the PCS via head mounted device (HMD), as well as estimate its usefulness for novices to improve spatial orientation during retrograde flexible nephroscopy.Materials & methods. Five residents without experience in self-performing retrograde flexible nephroscopy participated in a 7-day training course on the VR simulator developed, during which each novice studied six variants of the PCS. For the procedure simulation, a silicone kidney model was created with the stone placed in the calyx which was selected randomly in each case. Before and after VR-course, each resident assisted the experienced urologist during simulated retrograde nephroscopy to find the stone placed according to random selection. The nephroscopy time and the number of errors in stone-finding during retrograde flexible nephroscopy were analysed.Results. There was a statistically significant decrease in nephroscopy time (on avg by 17.6 minutes, p = 0.043) and errors to find targeted calyx, which was observed once after the training one resident only.Conclusion. The described VR simulator does not require significant time, technical and financial costs, and is available for wide implementation in the training of young specialists

Эндоскопически ретроградно контролируемое перкутанное лечение мочевых свищей после парциальной нефрэктомии

Background. Urinary fistulas (UFs) are one of the most significant complications after partial nephrectomy. Placement of an ureteral stent eliminates urine extravasation in the majority of patients. However, some of them have persistent UFs despite upper urinary tract drainage. Such cases require retrograde injection of fibrin glue into the renal cavity through a ureteroscope or via the percutaneous approach. Some authors reported cases of simultaneous use of 2 stents and percutaneous cryoablation of the fistula, but these techniques are rare and, therefore, it is problematic to evaluate their efficacy.Objective: to evaluate the results of the new treatment method for the elimination of persistent UFs using the retrograde endoscopic percutaneous approach.Materials and methods. This study included 5 patients (3 males and 3 females) with UFs developed after kidney resection. Mean age of the patients was 55.8 years. The tumor size was 2.5 to 4.8 cm; mean R.E.N.A.L. score was 7.8. All patients had earlier undergone minimally invasive partial nephrectomy; the time between surgery and UF development varied between 3 and 10 days. Four out of 5 patients had a large amount of discharge from their paranephral drainage system, examination of which confirmed high creatinine level. Patients underwent flexible ureteropyelography in the lithotomy position. During this procedure, we identified the damaged calyx and then performed percutaneous puncture targeting the distal end of the endoscope at this calyx, ensuring that the tip of the needle appeared in the paranephral cavity in front of the injured calyx. Using the flexible ureteroscope, we inserted the needle into the pelvis, dilated the puncture opening along the string, and installed a nephrostomy drainage system (12 Fr). Then the endoscope was removed and the ureter was additionally drained with a stent. The stent was removed after 8-10 days with subsequent antegrade pyelography. If there was no extravasation, the nephrostomy tube was removed and the patient was discharged from hospital to continue treatment in outpatient settings.Results. All patients with UFs resulting from partial nephrectomy was successfully operated on. No complications were registered. The mean surgery time was 45.0 ± 20.5 min (range: 40-65 min). Only two patients had some discharge from the fistula within 1 day after nephrostomy tube removal and it stopped without any additional interventions. Three patients had their fistula healed immediately. The treatment efficacy during the whole follow-up period of 18 ± 4 months (range: 6-26 months) was 100 %.Conclusion. Ureteral stenting ensures elimination of UFs in the majority of patients after partial nephrectomy. In individuals with persistent UFs, retrograde endoscopic percutaneous drainage of the pelvicalyceal system is the method of choice, because it allows rapid and effective treatment of UFs.Введение. Мочевые свищи (МС) являются одними из значимых осложнений парциальной нефрэктомии. У большинства пациентов установка мочеточникового стента приводит к ликвидации подтекания мочи. Однако у некоторых из них, несмотря на дренирование верхних мочевых путей, наблюдаются стойкие МС, при которых ретроградно через уретероскоп или перкутанным доступом в полостную систему почки вводится фибриновый клей. Описаны случаи одновременного использования 2 стентов, перкутанная криоаблация свищевого хода. Однако эти операции выполнялись только в единичных случаях, поэтому сложно оценить их окончательную эффективность. Цель исследования - изучение результатов предложенной нами методики ликвидации стойких МС путем ретроградно эндоскопически контролируемого перкутанного лечения. Материалы и методы. В исследование были включены 5 пациентов (2 мужчин, 3 женщины) с МС, развившимися после резекции почки. Средний возраст больных составил 55,8 года. Размер опухоли колебался от 2,5 до 4,8 см, среднее число баллов по нефрометрической системе R.E.N.A.L. составляло 7,8. Всем больным ранее выполнялась малоинвазивная парциальная нефрэктомия, сроки развития МС после нее колебались в пределах 3-10 дней. У 4 из 5 больных наблюдалось большое количество отделяемого по паранефральному дренажу, результат биохимического анализа которого подтвердил высокий уровень креатинина. В литотомическом положении выполняли гибкую уретеропиелоскопию, обнаруживали поврежденную чашку. Далее перкутанно прицельно на нее и дистальный конец эндоскопа проводили пункцию таким образом, чтобы кончик иглы появлялся в паранефральной полости напротив травмированной чашки. Под контролем гибкого уретероскопа иглу проводили в лоханку, по струне пункционный ход бужировали и устанавливали нефростомический дренаж 12 Шр. Эндоскоп извлекали и дополнительно проводили дренирование мочеточника стентом. Спустя 8-10 дней стент извлекали, выполняли антеградную пиелографию. При отсутствии затека из зоны МС нефростому извлекали и больного выписывали на амбулаторное лечение.Результаты. Все больные с МС после парциальной нефрэктомии были успешно прооперированы. Осложнений не зарегистрировано. Время операции составило в среднем 45,0 ± 20,5 (40-65) мин. После удаления нефростомического дренажа только у 2 больных в течение 1 дня наблюдалось отделяемое по свищу, которое самостоятельно прекратилось. У 3 пациентов свищ зажил сразу. Эффективность лечения за период наблюдения 18 ± 4 (6-26) мес составила 100 %. Заключение. Стентирование мочеточника позволяет ликвидировать МС у большинства больных после парциальной нефрэктомии. При стойких МС методом выбора может быть ретроградно эндоскопически контролируемое перкутанное дренирование чашечно-лоханочной системы почки, что позволяет в короткие сроки и с высокой эффективностью избавить больного от МС.