EFFECTIVENESS AND COMPLICATIONS OF PCNL IN PEDIATRIC PATIENTS WITH RENAL STONES THAT FAILED ESWL OR F.URS.

The prevalence of urolithiasis in pediatric patients is approximately 1%. However, all children diagnosed with urolithiasis are considered at high risk for stone recurrence, making complete stone clearance an essential goal of treatment. The choice of management is individualized and depends on the patient’s age, stone size, number and location, clinical condition, and urinary tract anatomy. Pediatric stone disease is often complex and may be associated with underlying metabolic disorders or structural abnormalities of the urinary system. ¹

Over recent decades, the management of renal stones has shifted from open surgery to minimally invasive techniques. Current treatment options include extracorporeal shock wave lithotripsy (ESWL), flexible ureteroscopy (FURS), and percutaneous nephrolithotomy (PCNL). According to the European Association of Urology (EAU) and the American Urological Association (AUA) guidelines, PCNL is the preferred treatment for renal stones larger than 2 cm.²

Pediatric PCNL was first reported in 1985 and has since enabled effective management of children with large stone burdens or in cases where ESWL is contraindicated or unlikely to succeed. PCNL in children has been performed using both adult and pediatric instruments. The rationale for miniaturized instruments (“mini-perc”) is to reduce morbidity while maintaining high stone clearance rates. Despite this, stone-free rates and complication profiles vary depending on the technique used and the surgeon’s experience. ² The objective of this study was to evaluate the safety and effectiveness of PCNL as a treatment modality for pediatric patients with renal calculi.

This prospective study was conducted from August 2024 to February 2025 at the Urology Unit, District Head Quarter Hospital Dir Lower Timergara and Regional Headquarter Hospital, Skardu. A total of 72 (36 of each center) children (<18 years) with renal stones, comprising large stones (>2 cm), lower calyceal stones (>1 cm), or smaller stones (<2 cm) that had failed previous treatment such as extracorporeal shock wave lithotripsy (ESWL) or flexible ureteroscopy (F.URS); ethical approval was obtained and informed consent was taken from parents/guardians, while all patients underwent preoperative evaluation including medical history, clinical examination, laboratory investigations, and imaging (X-ray KUB, ultrasonography, and non-contrast CT urography when indicated); PCNL was performed under general anesthesia using a standardized approach starting with urethro-cystoscopy to identify the ureteric orifice, followed by guidewire placement and insertion of an open-tip ureteric catheter, then repositioning for calyceal puncture and tract access, with stone fragmentation achieved using Holmium:YAG laser, pneumatic lithoclast, or ultrasonic lithotripter based on stone characteristics and instrument availability; postoperative care included monitoring for complications, pain control with IV NSAIDs, and antibiotics, with nephrostomy tube removal after 2–3 days in uncomplicated cases and DJ stent removal at 4 weeks in patients who were stone-free or had clinically insignificant residual fragments (≤4 mm); data were analyzed using SPSS version 20.0 to assess outcomes and complications, demonstrating a high success rate with 87.5% of patients being stone-free or having minimal residual stones.

Kidney stones, although traditionally thought to be uncommon in pediatric populations, have become an increasingly significant health concern, particularly in developing nations. These conditions are often associated with anatomical and metabolic abnormalities, as well as infections, which can lead to higher recurrence rates. Such challenges highlight the need for more efficient and minimally invasive treatments in this demographic [3, 4]. In the present study, treatment methods were guided by the stone burden, patient age, and the availability of instruments. For patients with larger stone burdens, older children required dilatation up to 24 Fr. In contrast, younger children had dilatation limited to 16 Fr, depending on the instrument available, including the 9.5 Fr semi-rigid ureteroscope or the 12 Fr MIP-M system. Previous studies have suggested that dilating to 24 Fr or 26 Fr in pediatric patients does not significantly increase morbidity. Traxer et al. [5] noted that using smaller access sizes does not yield better outcomes in terms of renal scarring, as observed in animal models. While some studies suggest a reduction in complication rates with smaller instruments, Bilen et al. [7] found no significant difference in complication rates when comparing devices of varying sizes. On the other hand, other 

studies have shown that smaller nephroscopes may help reduce morbidity and mortality rates [6]. Zeren et al. [8] demonstrated a correlation between intraoperative bleeding and factors such as stone burden, surgical time, and sheath size. The dilatation methods in our study included Amplatz dilators in the majority of cases, with a smaller proportion using single-step or telescoping metal dilators. Salerno et al. [9] reported that Amplatz dilators were the preferred choice in all cases of PCNL, while El-Nahas et al. [10] noted that coaxial telescopic dilators were commonly used in pediatric PCNL procedures. Holmium: YAG laser lithotripsy was the primary method of stone fragmentation in our study, with an average power of 30 W applied. Ultrasonic lithotripsy and pneumatic lithotripsy were used less frequently. Bujons et al. [11] employed a high-power Ho: YAG laser for treating difficult stones in pediatric patients, while Jou et al. [12] found that adjusting the power to 30 W improved efficiency. In a similar study, El-Nahas et al. [10] employed ultrasonic, pneumatic, and Ho: YAG lasers to fragment stones. Postoperative complications were managed with DJ stents and open-tip ureteric catheters. Rashid et al. [14] used DJ stents in 86% of cases, while Mahmood et al. [15] recommended routine DJ insertion. In our study, 62.5% of patients received DJ stents postoperatively, which aligns with the findings of other studies. Bleeding was a minor complication in our study, with only mild bleeding observed in 3 patients, and no cases required the procedure to be abandoned. Desai et al. [16] and Zeren et al. [17] have shown that bleeding is associated with factors such as tract size, stone load, and operative time. Gunes et al. [18] suggested that complications are more common in children under 7 years old when adult-sized equipment is used. According to Aron et al. [19], bleeding in PCNL is primarily due to torque applied to the nephroscope, and they recommend using multiple tracts instead of a single tract to minimize complications. Postoperative fever was observed in 4 patients (16.7%), with three experiencing low-grade fever and one experiencing high-grade fever. Similar findings were reported by Caione et al. [20], Mahmood et al. [13], and Sebaey et al. [21]. Hypothermia was absent in our patients, likely due to the regulated operating room temperature and the use of warmed saline for irrigation. Previous studies have confirmed the absence of hypothermia in similar settings [6, 22]. Urine leakage and colon injury were not observed in our study. Previous studies, such as those by El-Nahas et al. [10], Aldaqadossi et al. [22], Öztürk et al. [23], and Moussavi-Bahar et al. [24], have reported rare occurrences of urine leakage and colon injury in pediatric percutaneous nephrolithotomy (PCNL). Regarding the stone-free rate (SFR), our study demonstrated an 87.5% SFR after the initial percutaneous nephrolithotomy (PCNL) session, with only three cases of residual stones. Other studies, including those by Badway et al. [22] and Mahmood et al. [13], have reported success rates (SFRs) ranging from 84% to 94%, indicating the overall effectiveness of PCNL.

Limitations: The study's limitations include a relatively small sample size and a short follow-up period. Additionally, variability in the types of nephroscopes, lithotripters, and dilators used may have influenced the outcomes.

PCNL is a safe and effective method for treating large renal stones in children. Tailoring the tract dilation technique based on stone burden, patient age, degree of hydronephrosis, and available instruments is crucial. While miniaturization of instruments is important, optimization of techniques plays a more significant role in ensuring better outcomes.

Acknowledgement

The authors would like to thank all the participants for their valuable contribution to this study. There are no conflicts of interest to disclose, and no external funding was received for this research.

Authors' Contributions:

Sami Ul Haq: Contributed to study design, data collection, and manuscript writing.

Ghufran Ullah: Assisted in data collection and manuscript editing.

Aziz Ul Wahab: Contributed to data analysis and manuscript preparation.

Irshad Khan & Irshad Ahmad: Provided overall guidance, contributed to study design, data analysis, and manuscript writing.

The authors acknowledge the assistance of the entire urology department Timergara Teaching Hospital, Dir Lower, and RHQ Skardu for their support throughout the study.