Urine alkalinization, the mainstay of uric acid (UA) stone dissolution medical therapy, relies on old in vitro studies and expert opinions. Moreover, the effects of lowering urine UA concentration in patients without hyperuricosuria have rarely been investigated. We revisited the UA dissolution kinetics to determine the optimal alkalinization target and evaluate the effect of reducing urine UA saturation below normal levels. Ultraviolet-visible spectrophotometry was employed to analyze the dissolution kinetics of intact and grounded stones in artificial urine solution at various pH levels and UA concentrations. Crystal structures of precipitates were examined by X-ray diffraction. The average dissolution rate increased fourfold when the pH rose from 6–6.5 to 6.5–7 and ninefold when it reached 7–7.2, with the optimal level being at 7.2. At pH 7.4, the rate dropped significantly, and hydroxyapatite crystals precipitated. Grounded stones dissolved 10-fold faster than intact stones at each pH level. Lowering of the urine UA concentration enhanced the dissolution rate only at pH >6.5 and after reducing the concentrations by 55% of the normal level. The artificial urine, buffering solution, and model could only partially mimic the in vivo urine environment. The in vitro study of UA dissolution kinetics offers valuable insights for improving medical therapy in patients with UA nephrolithiasis. Our study confirms alkalinization as the key factor for dissolution and supports expert recommendations. Specifically, by maintaining urine pH >6.5, preferably 7–7.2, and increasing stone surface area, dissolution can be optimized. Reduction of UA concentrations in patients without hyperuricosuria enhances dissolution only after sufficient alkalinization. In this report, we used contemporary laboratory methods to refine the optimal pH target of urine alkalinization, the mainstay medical therapy for uric acid stone dissolution. We found the dissolution rate to increase mainly at pH levels above 6.5, with the optimal pH being 7.2. Additionally, increasing the stone surface area by fragmentation increased the dissolution further, implicating a potential second-line option when initial treatment is unsuccessful. Finally, we confirmed the expert-based recommendation on the lack of effectiveness of allopurinol treatment without adequate alkalinization in patients who have normal uric acid urinary excretion.

Objectives: Management of postoperative pain following percutaneous nephrolithotripsy (PCNL) is a significant goal. We sought to identify risk factors and clinical correlates of postoperative pain in order to improve perioperative management and patient satisfaction. Materials and methods: A single-center, retrospective analysis, from a prospectively maintained database, of all consecutive patients who underwent PCNL for renal calculi between January 2011 and August 2018. Postoperative pain was assessed using the visual analog scale (VAS) and analgesic use. We considered VAS score above 4 as meaningful. Pain management was standardized according to patirnt reported VAS scores. Multivariable logistic regression was performed to identify risk factors and clinical correlates. Results: A total of 496 patients were analyzed. Younger age was associated with VAS above 4 on the operative day and the first postoperative following PCNL ( p = 0.003 and p < 0.001, respectively). Female gender was associated with VAS above 4 in the first 2 days following the operation ( p < 0.001). Conclusions: Younger age and female gender would most likely benefit from pre-emptive improved pain management protocols following PCNL.

Introduction: Previous studies of pediatric urolithiasis have suggested possible associations between the relative proportions of calcium oxalate dihydrate (COD) and calcium oxalate monohydrate (COM) stones with age, gender, and ethnicity. This study aimed to investigate the composition and distribution of calcium oxalate stones according to these clinical factors and the metabolic correlates of the different subtypes in pediatric stone formers. Patients and Methods: We retrospectively reviewed the database of all first-time stone formers between 2014 and 2019. Infrared spectrometry was used to determine stone composition. Stones were categorized by their highest relative component and reported as a percentage of occurrences in the cohort as a whole and by patient gender, age (divided into three age groups: 1-5, 6-12, 13-18 years), and ethnicity. Clinical and metabolic correlates were analyzed. Results: Of 2,479 consecutive stones submitted to our chemical stone lab, 220 first-time pediatric stone formers were identified. COD stones were the predominant subtype in the youngest group, and COM stones in the oldest group (OR 0.39, 95% CI:0.18-0.86, p=0.036). In the intermediate-age group (6-12 years), COM stones were more prevalent in Arab boys and COD stones in girls of either ethnicity. COD stones were associated with hypercalciuria (p< 0.0001), and COM stones with hyperoxaluria (p=0.0024). Hypercalciuria and hypocitraturia were the most prevalent abnormalities at ages 1-5 and 13-18, respectively. Conclusions: Analysis of calcium oxalate stone subtypes and their metabolic correlates in stone formers has significant clinical relevance, specifically in children. In the present study, COD stones and hypercalciuria were more common in younger children, and COM stones and hypocitraturia in adolescents. These findings suggest unique, complex interactions driving stone formations in children that may guide a more practical, limited, and cost-effective approach to metabolic evaluations, choice of treatment, and preventive measures, particularly in first-time calcium oxalate pediatric stone-formers.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease affecting patients of reproductive age. Although HS shares risk factors with male infertility, only 1 epidemiological study has evaluated this association. To further evaluate this potential association, findings on semen and hormonal analysis, testicular ultrasound, and the International Index of Erectile Function (IIEF-15) were compared between 28 men attending a tertiary HS clinic during the period April 2019 to April 2021, and 44 healthy controls, spouses of infertile women undergoing semen evaluation before in vitro fertilization. Patients with HS were divided based on the absence or presence of gluteal and genital lesions. Patients with HS were younger than controls (median 27 vs 34 years, p < 0.0004) and had a higher proportion of smokers (86% vs 33%, p < 0.0001). Semen parameters in patients with gluteal-genital lesions, specifically those with severe scrotal involvement necessitating surgery, were lower than the WHO reference values and significantly lower than in patients without gluteal-genital lesions and controls. Erectile dysfunction was reported by 93% of patients with HS. These findings suggest that spermatogenesis and sexual function may be impaired in young men with HS. Therefore, multidisciplinary management of HS should include their evaluation to identify patients who might benefit from semen cryopreservation and sexual treatment.

Purpose: To compare long-term results following ureteroscopic stone fragmentation and removal versus stone dusting. Methods: We conducted a retrospective analysis of patients who underwent ureteroscopy for renal calculi at two high-volume tertiary centres between 2012 and 2013, therefore allowing long-term follow-up. The surgeons differed in their technique, some performing dusting for the most part and the others fragmentation. Inclusion criteria were stone free at the first follow-up and the sole use of laser lithotripsy is either by dusting or by fragmentation. Operative and post-operative data as well as re-treatment rates were compared between the groups. Stone-free rates and long-term stone recurrence rates were analysed by a single radiologist blinded to the treatment technique. Results: Between 2012 and 2013, 669 ureteroscopies were performed at both centres. The study group included 100 patients, which met the inclusion criteria, equally distributed between dusting and fragmentation. The cumulative stone diameter in patients treated with dusting was significantly larger (12.7 mm versus 17 mm, p = 0.006). Operative time was shorter in patients treated with dusting (56 minutes versus 47.2 minutes, p = 0.6). The mean follow-up was 58.9 (standard deviation (SD) 17.2) and 69.4 (SD 13.8) months for the fragmentation and dusting-treated patients, respectively( p = 0.06). The long-term recurrence rate in the fragmentation group was 22% compared to 38% in the dusting group ( p = 0 .08). Most of the patients in the dusting group required a repeat ureteroscopy during their follow-up (28% versus 6%, p = 0.003). A multivariable logistic regression analysis revealed that the fragmentation was not associated with a lower stone recurrence rate when compared to dusting (OR 0.6, 95% CI 0.199-1.810, p = 0.3). Conclusions: The recurrence rate of renal stones was not significantly influenced by the choice of surgical techniques. However, dusting was associated with a greater need for repeat ureteroscopy than fragmentation with removal. Level of evidence: Not applicable