Background Cost-effective methods to facilitate practical medical education are in high demand and the “mixed-reality” (MR) technology seems suitable to provide students with instructions when learning a new practical task. To evaluate a step-by-step mixed reality (MR) guidance system for instructing a practical medical procedure, we conducted a randomized, single-blinded prospective trial on medical students learning bladder catheter placement. Methods We enrolled 164 medical students. Students were randomized into 2 groups and received instructions on how to perform bladder catheter placement on a male catheterization training model. One group (107 students) were given their instructions by an instructor, while the other group (57 students) were instructed via an MR guidance system using a Microsoft HoloLens. Both groups did hands on training. A standardized questionnaire covering previous knowledge, interest in modern technologies and a self-evaluation was filled out. In addition, students were asked to evaluate the system’s usability. We assessed both groups’s learning outcome via a standardized OSCE (objective structured clinical examination). Results Our evaluation of the learning outcome revealed an average point value of 19.96 ± 2,42 for the control group and 21.49 ± 2.27 for the MR group - the MR group’s result was significantly better ( p = 0.00). The self-evaluations revealed no difference between groups, however, the control group gave higher ratings when evaluating the quality of instructions. The MR system’s assessment showed less usability, with a cumulative SUS (system usability scale) score of 56.6 (lower half) as well as a cumulative score of 24.2 ± 7.3 ( n = 52) out of 100 in the NASA task load index. Conclusions MR is a promising tool for instructing practical skills, and has the potential to enable superior learning outcomes. Advances in MR technology are necessary to improve the usability of current systems. Trial registration German Clinical Trial Register ID: DRKS00013186

Die 41-jährige IIIG/IP wird erstmals in der 30+3. SSW mit neu aufgetretener fetaler abdomineller Raumforderung vorgestellt, diese war 6 Wochen zuvor sonographisch noch nicht darstellbar gewesen. Nun zeigt sich sonographisch ein 66 × 56 × 66 mm großer Tumor der linken Niere mit ausgedehnter Gefäßversorgung bei makrosomem Feten. Durch die hinzugezogene Kindernephrologie wird die Verdachtsdiagnose kongenitaler Wilms-Tumor mit den Differentialdiagnosen mesoblastisches Nephrom DD Neuroblastom gestellt. Im fetalen MRT zeigt sich ein solide imponierender Tumorprozess, V.a. mesoblastisches Nephrom, Volumen 160 ml. Mehrfach wird in den kommenden Wochen bei symptomatischem Polyhydramnion Grad 3 entlastungspunktiert, der Tumor vergrößert sein Volumen in 3 Wochen auf über 400 ml. Der Fall wird in der pädiatrisch-onkologischen Tumorkonferenz vorgestellt; gemeinsam wird die Entscheidung getroffen, die Schwangerschaft trotz der deutlichen Größenzunahme des Tumors zu prolongieren. In der 34+3. SSW kommt es zum spontanen Blasensprung 3 Tage nach der letzten Entlastungspunktion. Es wird eine komplikationslose sekundäre Sectio durchgeführt. In der Erstversorgung durch die Neonatologen zeigt sich ein tief zyanotisches, makrosomes Neugeborenes ohne Spontanatmung mit einer HF von 100/min, APGAR 3/5/5, pH 7,31, BE -2,3, Geburtsgewicht 3000 g. Aufgrund der respiratorischen Insuffizienz durch die große abdominelle Raumforderung wird sekundär intubiert. Am 3. Lebenstag erfolgt eine transperitoneale radikale Tumornephrektomie links mit Staginglymphadenektomie. Die Operation gestaltet sich aufgrund der starken Tumorvaskularisation sehr schwierig mit ausgeprägtem Blutverlust, insgesamt 1,5-facher Austausch des gesamten Blutvolumens und Katecholamintherapie über 2 Tage. In der Histologie zeigt sich ein mesoblastisches Nephrom vom klassischen Typ mit tumorfreier Staginglymphadenektomie, Stadium II nach SIOP. Das Neugeborene kann nach Stabilisierung am 22. Lebenstag nach Hause entlassen werden. Die bisherige Nachsorge verläuft unauffällig.

Case report: A 41-year-old GIII/PI presented for the first time at 30+3 weeks of pregnancy with a newly diagnosed fetal abdominal mass, which hadn't been visible 6 weeks before. At present, sonography reveals a 66 × 56 × 66 mm left renal mass with abundant vascularisation and a macrosomic male fetus. The right kidney is normal in size and shape. The consulted pediatric nephrologist suspects a wilms tumor or a mesoblastic nephroma. Fetal MRT shows a solid mass, 160 ml in volume, the radiologists suspect a mesoblastic nephroma. Because of the maternal pain and respiratory distress of the severe polyhydramnios amnioreduction is performed weekly. During the following three weeks the tumor grows from 160 ml to almost 400 ml. The case is presented to the pediatric oncology board; together, it is decided to allow the pregnancy to go to term despite the fast growth of the tumor. At 34+3 weeks of pregnancy, a spontaneous rupture of membranes occurs 3 days after the last amnioreduction. A cesarean section is performed at the mothers request without complication. The newborn is cyanotic without spontaneous breathing, APGAR 3/5/5, pH 7.31, BE -2.3. Intubation is necessary because of the respiratory failure caused by the big abdominal mass.

A 72-year-old woman sustained a ureteric avulsion following circulatory collapse at home. Urosonographic imaging revealed hydronephrosis at the left kidney, and abdominal emergency computed tomography showed some fluid around it. Left retrograde pyelography proved ureteral disruption at the level of the ureteropelvic junction (UPJ). Immediate open surgery was performed to restore ureteropelvic continuity. Correct and early diagnosis of UPJ transsection is difficult under emergency service conditions and lack of symptoms. With the rapid increase in the aging population, the presence of degenerative exostoses will increase, and its exclusive pathomechanism and pattern of injury might be seen more frequently in emergency care. Trauma specialists should be aware of this pathology.

Partial circumcision techniques frequently lead, on account of the remaining foreskin, to functional complications and unsatisfactory cosmetic results requiring re-operation. A series of pictures taken from our own sample of patients illustrates the problem. Review of the literature also attests to higher complication rates after partial circumcision. From a medical point of view, complete circumcision is preferable.

Hintergrund: Einzelnieren (definiert als anatomische oder funktionelle Einzelniere mit >90% Funktionsanteil im ING) stellen einen häufigen Vorstellungsgrund in der Kindernephrologie dar. Unterschiedliche Empfehlungen zu den möglichen diagnostischen Maßnahmen werden diskutiert.

Article Extrakorporale piezoelektrische Stosswellenlithotripsie - Datenhaltung mit Foxbase was published on January 1, 1988 in the journal Biomedical Engineering / Biomedizinische Technik (volume 33, issue s2).

Aims: To explore the clinical course of children with "single kidney'' ( defined as either a solitary or single functioning kidney) with reference to renal function ( glomerular filtration rate (GFR) and proteinuria), body height and particularly sonomorphological features.Patients and methods: This retrospective monocentric study evaluated 119 children with a solitary or single functioning kidney (>90% unilateral function on isotope scan) between 1997 and 2007. Patients were followed for 6.3 years ( median, range 1-17) and had at least three renal ultrasound examinations (median 8). During recruitment six children were identified with chronic kidney disease (CKD) stage III or worse. These patients were analysed separately.Results: The aetiology of "single kidney'' was attributed to contralateral multicystic dysplastic kidney (26%), tumournephrectomy (24%), renal agenesis (18%), hypo/dysplasia (11%) and obstructive or refluxive uropathy (18%). Irrespective of aetiology, the sonographic dimensions of "single kidneys'' were in the upper range of normal paired kidneys and showed adequate growth. Compensatory renal hypertrophy ( defined as >95% CI on two or more recent measurements) occurred in a third of patients. All six patients with CKD and GFR less than 60 ml/minute per 1.73 m(2) had pathological sonomorphology of their "single kidney'' with inadequate renal growth (6/6), abnormal echogenicity (5/6), hypo/dysplasia (5/6). In addition, proteinuria (5/6) and short stature (3/6) were found.Conclusions: New reference centiles were generated to assess renal size of "single kidneys'' in paediatric patients. These charts will facilitate counselling of patients and parents. Further evidence for a benign clinical course of children with "single kidney'' and absent additional pathology of the remnant kidney is presented.

BACKGROUND A diagnostic workup of a renal mass will rarely lead to the diagnosis of a tubulopathy. We would like to stress the importance of taking a detailed history and of evaluating these findings in the context of the clinical symptoms. CASE REPORT A 3 year old boy with a renal mass, diagnosed due to urinary tract infection, was referred to exclude renal malignancy. Detailed history revealed polyuria and polydipsia in a child with preterm delivery due to polyhydramnios. These symptoms, together with poor thriving are highly suggestive of a neonatal form of Bartter syndrome. This diagnosis was substantiated by ultrasound findings of nephrocalcinosis and urolithiasis due to hypercalciuria and a renal abscess. Detection of mutations in the KCNJ1-gene confirmed the diagnosis. After unilateral nephrectomy for acute destructive nephritis and under medication with indomethacin and potassium citrate the patient is now thriving well. CONCLUSION Renal masses suspicious of malignancy may distract from a hereditary tubulopathy. Typical clinical history and presentation with prematurity, polyhydramnios, polyuria, poor thriving and urolithiasis requires diagnostic evaluation of tubular function since routine laboratory tests and urinary dip stick may be normal. Unrecognized, neonatal Bartter syndrome may lead to severe complications including loss of kidney function.

Background: Flank swelling and pseudotumors of the kidney are unusual manifestations of obstructive uropathies in small children. Our case illustrates typical problems and briefly reviews management options. Case report: A 5-week-old boy presented with a large, palpable urinoma due to posterior urethral valves. Sonography and voiding cystourethrogram led to the diagnosis and immediate suprapubic transcutaneous urinary diversion was performed. However, the urinoma did not resolve. Thus, in addition to suprapubic urinary diversion, indirect drainage - instead of percutaneous puncture - was performed by retrograde insertion of a double-J catheter. Urethral valves were resected 4 weeks later and follow-up demonstrated an uneventful further development with normal renal function as assessed by regular ultrasound studies, a repeat cystourethrogram and a renal scan. Conclusion: Perirenal urinomas may be the first symptom in patients with posterior urethral valves. Drainage via double-J stenting offers a promising alternative to percutaneous puncture. A renoprotective "pop-off" mechanism by which intrarenal pressure may be relieved is discussed.

RARE-MR-urography (Rapid Acquisition with Relaxation Enhancement) is a fast MR imaging technique (6.4 s/acquisition) that selectively depicts fluid by heavy T2-weighting. From 9/1989 to 11/1990, RARE-MR urograms were prospectively evaluated in the diagnosis of upper urinary tract abnormalities in 55 children. The method is performed in several planes and combined with a coronal, T1-weighted spin-echo sequence. Forty out of 42 kidneys with dilated renal pelvis, and 21 out of 24 dilated ureters were identified, only the mildly dilated ones were missed. Even in non-functioning kidneys the urinary tract was clearly depicted by RARE-MR-urography. However, no differentiation could be made with this technique between vesicoureteral reflux and non-refluxing dilatation of ureter and/or renal pelvis. All 19 pelviureteric obstructions and all eight renal duplications with a dilated segment were identified. RARE-MR-urography is a new tool for diagnosing urinary tract abnormalities in children without having to employ ionizing radiation, contrast media, or general anesthesia. A dilated urinary tract can be shown in one image displaying the entire urinary system, similar to excretory urography. The technique is presently not able to provide the information of voiding cystourethrography or renal scintigraphy, nor is it as easy to perform as ultrasound. However, in certain cases it may replace excretory urography.

SINCE THE ADVENT of kidney transplantation, urological complications have been a major concern. The published incidence varies between 2% and 33% in different series. Due to the limited arterial perfusion of the ureter exclusively from the renal vessels following nephrectomy, an ischemic injury to the ureter commonly leads to necrosis with consecutive urinary leakage of the ureteroneocystostomy or to fibrosis resulting in urinary obstruction. We report a case of corrective surgery to restore urinary continuity using a vascularized intestinal segment in a modified Monti procedure after partial necrosis of the graft pelvis following living related renal transplantation.

During the last 15 years extracorporeal shock wave lithotripsy (ESWL*) has been used in the treatment of urolithiasis with pregnancy considered a strict contraindication.(1) There is lack of knowledge concerning the possible effects of shock wave therapy on the development of a human embryo or fetus. We report a case of successful experimental piezoelectric shock wave lithotripsy of an obstructing ureteral stone in an advanced pregnancy.