Mini-versus standard percutaneous nephrolithotomy in pediatric population: A randomized controlled trial.

INTRODUCTION: Mini PCNL has gained popularity in adult patients due to reduction in the complication rate with comparable stone free rate. There is paucity of level 1 evidence regarding the benefit of mini PCNL in the pediatric group. OBJECTIVE: We performed a randomised study to compare mini PCNL (mPCNL) with standard PCNL (sPCNL) for the management of renal calculi in patients less than 18 years of age in terms of safety, efficacy, and stone-free rate (SFR). MATERIALS AND METHODS: A randomised controlled trial was performed on 50 children who underwent PCNL from June 2015 to March 2021, who were divided into two groups. Group I had 25 patients managed with mPCNL (sheath size 16.5 Fr) and Group II had 25 patients who underwent sPCNL (sheath size 26 Fr). Primary outcomes including stone free rates (SFR) and hemoglobin drop and secondary outcomes like operative time, complications, pain score, need of analgesia, incidence of nephrostomy site leak, hospital stay in days were compared between the two groups. RESULTS: The mean age of patients in groups I and II was 9.4 ± 2.6 and 10.4 ± 2.26 years, respectively (p = 0.15). The mean stone sizes in both groups I and II were 18.6 ± 2.56 and 20.2 ± 3.58 mm, respectively (p > 0.05). The stone free rate for group I was 88% and for group II, 92% (p = 0.64). The average drop in hemoglobin was higher in group II compared to group I (1.1 ± 0.31 g/dl and 1.7 ± 0.23 g/dl respectively; p < 0.0001), however the mean blood transfusion rate was not significantly different in both groups. The operating time was shorter in group II compared to group I (p-value - 0.0030). The pain scores were lesser for the group I. Grade I complications were higher in group II as compared to group I (p-0.047); however, grade II complications were comparable in both groups. The mean hospital stay was not significantly different in both groups. DISCUSSION: This study confirms the role of mini PCNL in pediatric patients with renal stones. The stone clearance rate of mini PCNL is equivalent to standard PCNL, with lesser blood loss and postoperative complications, however with longer operative time during mPCNL. The small number of the participants in both arms is a limitation of this study and may also reflect fewer children with urolithiasis being treated surgically even in a tertiary care referral centre. CONCLUSIONS: Mini-PCNL offers equivalent stone free outcome with lower complications rate compared to the standard PCNL for all types of renal stones.

Long term outcomes of Cohen's cross trigonal reimplantation for primary vesicoureteral reflux in poorly functioning kidney.

BACKGROUND: Open ureteric reimplantation by cross trigonal technique described by Cohen is considered a common surgical option for correction of vesicoureteral reflux (VUR). There is a lack of evidence in literature though for what happens to such kidneys, in the long run, particularly those which are poorly functioning. AIM: To assess the long-term outcomes of ureteric reimplantation in poorly functioning kidneys in children with unilateral primary VUR. METHODS: Children with unilateral primary VUR and a relative renal function of less than 35% who underwent open or laparoscopic ureteric reimplantation between January 2005 and January 2017 were included in the study. Patients who had a follow up of less than five years were excluded. Preoperative evaluation consisted of a voiding cystourethrogram and Dimercaptosuccinic acid (DMSA) scan. In the follow-up period, patients underwent a diuretic scan at 6 weeks and 6 months. Follow up ultrasound was done for change in grade of hydronephrosis and retrovesical ureteric diameter. Subsequent follow up was done at 6 monthly intervals with evaluation for proteinuria and hypertension and any recurrent urinary tract infection (UTI). For assessment of cortical function, DMSA was repeated annually for 5 years after surgery. A paired-samples t-test was used to test the mean difference of DMSA between pre-post observations. RESULTS: During this period, 36 children underwent ureteric reimplantation for unilateral primary VUR. After excluding those with insufficient follow-up, 31 were included in the analysis. Most of the patients were males (n = 26/31, 83.8%). Patient's age (mean ± SD, range) was 5.21 ± 3.71, 1-18 years. The grades of VUR were grade II (1 patient), grade III (8 patients), grade IV (10 patients), and grade V (12 patients). The pre and postoperative DMSA was 24.064 ± 12.02 and 24.06 ± 10.93, which was almost the same (statistically equal, paired-samples t-test: P = 0.873). The median (range) follow-up duration was 82 (60-120) mo. One patient had persistent reflux after surgery (preoperative: grade IV, postoperative: grade III), and the very same patient developed recurrent UTI. The difference in the preoperative and postoperative DRF was less than 10% in 29 patients. In one patient, the DRF decreased by 17% (22% to 05%) while in another patient, the DRF increased by 12% (25% to 37%) after surgery. None of the patients had an increase in scarring after surgery. 15% of patients were hypertensive before surgery and all of them continued to be hypertensive after surgery while none developed hypertension after surgery. None of the patients had significant proteinuria (> 150 mg/d) during the follow-up period. CONCLUSION: Children with unilateral primary VUR and poorly functioning kidney maintain the renal function over the long term in most cases. Hypertension and proteinuria do not progress over time in these patients.

OptiDistillNet: Learning nonlinear pulse propagation using the student-teacher model.

We present a unique approach for learning the pulse evolution in a nonlinear fiber using a deep convolutional neural network (CNN) by solving the nonlinear Schrodinger equation (NLSE). Deep network model compression has become widespread for deploying such models in real-world applications. A knowledge distillation (KD) based framework for compressing a CNN is presented here. The student network, termed here as OptiDistillNet has better generalisation, has faster convergence, is faster and uses less number of trainable parameters. This work represents the first effort, to the best of our knowledge, that successfully applies a KD-based technique for any nonlinear optics application. Our tests show that even by reducing the model size by up to 91.2%, we can still achieve a mean square error (MSE) which is very close to the MSE of 1.04*10-5 achieved by the teacher model. The advantages of the suggested model include the use of a simple architecture, fast optimization, and improved accuracy, opening up applications in optical coherent communication systems.

Two-Dimensional Weak Antilocalization Signatures Due to Quantum Coherent Transport in Nanocrystalline SnTe.

Nanostructured topological crystalline insulators (TCIs) in the presence of exotic surface states with spin momentum locking reported in individual nanostructures are predicted to hold a great promise for spintronics and quantum computing applications. However, practical application demands a strategy with large-scale production and integration for device applications. In this work, we demonstrate through prominent signatures of weak antilocalization (WAL), arising predominantly from destructive quantum interference on robust surface states, that a correlated TCI phase is possible in the nanobulk assembly of carefully nanostructured quasi-two-dimensional SnTe (edge-to-edge length ∼ 382 nm) synthesized by a simple, rapid, and scalable microwave-assisted solvothermal method. Hikami-Larkin-Nagaoka analysis (T-0.71), as well as the temperature dependence of resistivity, illustrates an interplay of both conductions from 2D channels and 3D EEI effects as the precursor for the observed WAL at low temperatures (2-6 K). Interestingly, the enhanced thermoelectric power of the sample of ∼45 µV/K, with a p-type carrier concentration of ∼1018/cm3 at 300 K, makes this SnTe nanocrystalline assembly more attractive as a multifunctional material for large-scale technological applications.

Role of ureterocalicostomy in management of giant hydronephrosis in children in contemporary practice: Indications, outcomes and challenges.

INTRODUCTION: Given the rarity of giant hydronephrosis (GH), ideal surgical approach, assessment of drainage after surgery, expected improvement in renal function and morphological changes in the kidney on follow up have not been studied extensively. The aim of this study was to investigate the role of ureterocalicostomy (UC) in unilateral GH with respect to its current indications, outcomes and the challenges associated with it. MATERIALS AND METHODS: We retrospectively analysed data of 25 children (up to the age of 18 years) who underwent UC between January 2008 and January 2019 using open, laparoscopic or robotic-assisted approach. Preoperative workup included ultrasonography for pelvic anteroposterior diameter (APD) and cortical thickness (CT), and diuretic scan for split renal function (SRF) and drainage. Patients were followed with ultrasonography and diuretic renal scan at 3 months, after further 6 month and then annually. RESULTS: The median age was 7 years and median follow-up was 22 months. Eight children underwent UC as salvage procedure while 17 children underwent UC as an upfront procedure. APD declined significantly (p < 0.001) and CT improved significantly (p = 0.009) after surgery. The drainage as well as SRF did not change significantly after surgery. Four children developed flank pain after stent removal; one required a redo-ureterocalicostomy for anastomotic stricture while another required balloon dilatation of the anastomosis. Two children responded to prolonged stenting for 2 months. DISCUSSION: Ultrasonography (APD, CT), Diuretic renal scan (SRF and drainage pattern) are used to monitor HDN. APD is particularly important in GH because the diuretic renogram invariably shows an obstructive drainage owing to the large volume of the pelvicalyceal system. Similar to previous studies in literature, we too reported a decline in APD. CT improved in our study, however, the drainage pattern as well as SRF did not change significantly (Figure). Diuretic scan in isolation was not sufficient to predict failure. A combination of ultrasonographic and diuretic scan parameters were useful for follow up and for detection of failure. The success rate in our study was 92%. Chief limitations of our study were retrospective nature and lack of comparison with pyeloplasty. Moreover, some cases were performed with minimal invasive techniques, so the study group was heterogenous. CONCLUSIONS: UC offers excellent outcome in children with GH due to primary as well as secondary UPJO. Isolated ultrasonographic or diuretic renogram parameters are not sufficient to predict failure and a combination of them should be used for follow up after UC.

A robust nitridation technique for fabrication of disordered superconducting TiN thin films featuring phase slip events.

Disorder induced phase slip (PS) events appearing in the current voltage characteristics (IVCs) are reported for two-dimensional TiN thin films produced by a robust substrate mediated nitridation technique. Here, high temperature annealing of Ti/Si3N4 based metal/substrate assembly is the key to produce majority phase TiN accompanied by TiSi2 & elemental Si as minority phases. The method itself introduces different level of disorder intrinsically by tuning the amount of the non-superconducting minority phases that are controlled by annealing temperature (Ta) and the film thickness. The superconducting critical temperature (Tc) strongly depends on Ta and the maximum Tc obtained from the demonstrated technique is about 4.8 K for the thickness range ~ 12 nm and above. Besides, the dynamics of IVCs get modulated by the appearance of intermediated resistive steps for decreased Ta and the steps get more prominent for reduced thickness. Further, the deviation in the temperature dependent critical current (Ic) from the Ginzburg-Landau theoretical limit varies strongly with the thickness. Finally, the Tc, intermediate resistive steps in the IVCs and the depairing current are observed to alter in a similar fashion with Ta and the thickness indicating the robustness of the synthesis process to fabricate disordered nitride-based superconductor.

Evaluation of polyuria and polydipsia along with other established prognostic factors in posterior urethral valves for progression to kidney failure: experience from a developing country.

BACKGROUND: Up to 50% of children with posterior urethral valves (PUV) progress to kidney failure. This study aimed to evaluate polyuria and polydipsia and other established variables with later development of kidney failure in children with PUV. METHODS: Retrospective analysis of 297 children with PUV who underwent ablation of valves between January 1992 and January 2015 at our tertiary care center. Patients were divided into two groups: those who developed kidney failure (group 1) and those who did not (group 2). Specific prognostic factors for progression to kidney failure were analyzed including age at presentation < 1 year, nadir serum creatinine > 1.0 mg/dl, bilateral grade 3 or higher VUR at diagnosis, recurrent febrile UTIs, severe bladder dysfunction, polyuria, and polydipsia. RESULTS: Thirty-eight (12.8%) patients progressed to kidney failure. Twenty-four and 64 patients were polyuric in group 1 and group 2 respectively (p < 0.001, Z-4.4666). Twenty-two and 61 patients were polydipsic in both groups respectively (p < 0.001). On univariate analysis, predicting variables were as follows: age at presentation < 1 year (p < 0.001), nadir serum creatinine > 1 mg/dl (p < 0.001), B/L high-grade VUR (p < 0.001), severe bladder dysfunction (p < 0.001), recurrent febrile UTIs (p = 0.002), polyuria (p < 0.001), and polydipsia (p < 0.001). On multivariate Cox regression analysis, severe bladder dysfunction, recurrent febrile UTIs, polyuria, and polydipsia were identified as significant prognostic factors predictive of ultimate progression to kidney failure. CONCLUSION: Polyuria and polydipsia along with recurrent febrile UTI and bladder dysfunction are major prognostic factors affecting long-term kidney outcome in cases of PUV. Graphical abstract.

Urinary Bladder Xanthoma - Is Immunohistochemistry Necessary?

Urinary Bladder Xanthomas (UBX) are non-neoplastic reactive tumor like process. Isolated UBX is rare with only around 15 cases reported (Yu, Patel, & Bonert, 2015). UBX are reported in older patients who present with non specific symptoms like UTI or hematuria. Patients often have associated lipid anomalies. UBX have been vaguely described as yellowish white plaques or patches. Also, recent reports have stressed on the role of Immunohistochemistry in the diagnosis (Al-Daraji, Varghese, & Husain, 2007; Vimal, Masih, Manipadam, & Chacko, 2012). The objective of this report is to provide a cystoscopic view of the tumor which will enable easier identification and also to debate on the role of IHC in diagnosis.

Paradidymis - Fact/Fiction and its Significance.

A 30-year old infertile male was admitted for microsurgical sub inguinal varicocelectomy. Intraoperatively, two tubular structures of the caliber of neighboring veins were noted. They were distinct from the vas, which was carefully preserved. Histopathology revealed varicose veins along with two convoluted tubular structures lined by ciliated pseudo-stratified epithelium. There was an incomplete thin muscle coat. The lumina were irregular and contained no spermatozoa (Fig. 1). These structures were identified as paradidymis based on the location in the cord and microscopic morphology. We have tried to analyze the medico-legal significance of these benign lesions in our every day practice.