Evaluating Natural History and Follow Up Strategies for Non-obstructive Urolithiasis in Pediatric Population

Minimally invasive removal of obstructive ureteral stones by intracorporeal lithotripsy in horses: 3 patients

Three client-owned horses diagnosed with obstructive ureteral stones were referred and treated in a minimally invasive manner by retrograde ureteroscopy in conjunction with electrohydraulic lithotripsy (EHL) or laser Holmium:YAG lithotripsy (HYL). For all 3 horses, additional tests revealed variable degrees of azotemia and ureteral obstruction. Ultrasound examination (2 horses) revealed a loss of cortico-medullary distinction consistent with a chronic nephropathy. Ultrasound-guided biopsy of the right kidney in 1 horse revealed moderate glomerulosclerosis and lymphoplasmacytic nephritis. A standing anesthesia with a coccygeal epidural was done for each horse. A perineal urethrotomy was performed in 2 horses before the urethrocystoscopy. One horse was treated with Holmium:YAG laser lithotripsy and 2 others were treated using a electrohydraulic lithotripsy probe. Each procedure was successful. The ureteroscopy was successfully performed and visualization was excellent. Fragmentation of stones seemed easier with the electrohydraulic lithotripsy probe. No complications, pain, or signs of discomfort after the procedure were noticed. All 3 horses were discharged from the hospital. Key clinical message: Obstructive ureteral stones in horses can be successfully treated in a minimally invasive manner by retrograde ureteroscopy accompanied by lithotripsy. This technique is safe, not painful and did not require general anesthesia. Electrohydraulic lithotripsy appeared superior for stone fragmentation.

Is medical treatment necessary for infants with small urinary stones?

Urinary stone disease is a common condition. We investigated the usefulness of medical treatment for infants with urinary stones 5 mm or smaller. The study included 197 infants (86 girls and 111 boys) with urolithiasis ≤ 5 mm who were referred to our Department of Nephrology between 2014 and 2016. Infants with metabolic or anatomical risk factors requiring medical treatment were excluded from the study. We retrospectively reviewed urine and serum metabolic profiles and compared stone resolution rates in patients who did and did not receive treatment. The mean age at diagnosis was 5.2 months (range, 14 days to 12 months). The most common complaint was restlessness (n = 92, 46.7%), and 49 infants (24.9%) were asymptomatic. Multiple stones were detected in 166 infants (84.3%). Hypomagnesuria, hypocitraturia, and hypercalciuria were present in 25.3, 19.7, and 18.7% of patients, respectively. Stones < 3 mm (microlithiasis) were detected in 97 infants (49.2%), and 100 (50.8%) patients had 3-5 mm stones. In total, 130 infants (66.5%) received regular treatment and 67 (33.5%) were not treated. Stone resolution was significantly higher in the group receiving K-citrate treatment at the 6th month follow-up, while there were no significantly difference between the two groups at the 12th month control. No previous studies have investigated treatment outcomes in infants with 3-5 mm urinary stones. According to our results, K-citrate treatment may accelerate the resolution of the stone in infants with stones smaller than 5 mm.

Flexible ureteroscopy versus miniaturized percutaneous nephrolithotomy for renal stones of 1-2 cm

Technological advances and innovation in endourology have significantly reduced the indications of extracorporeal shockwave lithotripsy in the management of moderate-sized renal stones. In the last decade, we have witnessed a trend towards the use of finer scopes for percutaneous procedures instead of standard percutaneous nephrolithotomy (PCNL) (≥22 Fr). Miniaturized PCNL (mPCNL), i.e. miniPCNL (12–20 Fr), ultra-miniPCNL (11–13 Fr), mini-microPCNL (8 Fr), and microPCNL (<5 Fr), is increasingly being used. Concomitant developments in laser technology have provided a safe and effective stone fragmentation modality for use via flexible ureteroscopes (fURS). Technological advances in the design of fURS have improved not only the optics (fiber optic to chip-on-the-tip technology digital image) but also the ergonomics. Both the endourological techniques are extremely effective and safe, as shown in a multitude of good-quality studies. There are some differences in stone-free rate and complications. mPCNL in general has a higher stone-free rate, albeit with a slightly higher incidence of hemorrhagic complications. fURS often requires longer stenting time and longer period to achieve stone clearance, whereas mPCNL often needs ureteral catheter for only 24 hours and has a higher first day stone-free rate. fURS is a 1 day procedure compared to mPCNL, which requires patients to stay hospitalized for 2–3 days. It is therefore important to tailor the indications of these two procedures to the individual patient’s needs.

Urologic treatment of nephrolithiasis

PURPOSE OF REVIEW

The purpose of this review is to describe the options and recent developments in the urologic treatment of nephrolithiasis in children. The prevalence of nephrolithiasis in children has increased over time. The urologic treatment of nephrolithiasis ranges from observation to medical expulsive therapy with an alpha blocker for a stone in a ureter to a variety of procedures for stone removal.

RECENT FINDINGS

Observation for small, asymptomatic renal stones is a reasonable strategy in children. Medical expulsive therapy with an alpha blocker may have a beneficial effect for passage of ureteral stones in children. Extracorporeal shock wave lithotripsy (ESWL) remains an important treatment for nephrolithiasis in children. Advances in ureteroscopy with clearer digital imaging and single use ureteroscopes have made ureteroscopy more attractive. Percutaneous nephrolithotomy is a more invasive treatment modality but remains a good choice for children with large-stone burdens and instruments are getting smaller. Open or laparoscopic stone surgery should be reserved for unique cases.

SUMMARY

Nephrolithiasis is increasing in children with differing urologic management options depending on the clinical scenario. A shared decision-making process with discussion of risks and benefits should be used to help patients and families choose a treatment option.