Safety and efficacy of percutaneous nephrolithotomy in patients with a single functioning kidney compared to patients with bilateral functioning kidneys

Introduction

Urolithiasis is a frequent disorder affecting the urinary system. Globally, urinary stones are represented at a prevalence of 5–12% in males and 4–7% in females¹. Percutaneous nephrolithotomy (PCNL) is the best choice for treatment of stones, giving a high stone-free rate and increased safety when compared to other techniques². The PCNL is used for management of stones sized 2 cm³ and above³. In spite of these PCNL advantages, it is often accompanied by many complications, such as bleeding, collecting system injury, urinary leakage, infection, kidney damage and death⁴. Solitary kidney is defined as the condition where an individual has a single functioning kidney as compared to normally two kidneys. The incidence of stones in patients with solitary and bilateral kidneys are same rate⁵. The complications reported during and after PCNL of patients with solitary kidney were uncontrolled bleeding, need for angio-embolization or nephrectomy and subsequent need for kidney transplant⁶.

This study aimed to compare the effectiveness and safety outcomes of PCNL in patients with single functioning kidney in comparison to PCNL outcomes in patients with bilateral functioning kidneys.

Methods

Data sources and collections

Assessment of patients was done by the researcher during preoperative, operative and postoperative periods. Full history and examination of patients was firstly done by the researcher and then patients were sent to the Laboratory and Radiology departments of hospital to undergo complete blood and radiological investigations. Diagnosis of renal stones was conducted by the researcher depending on clinical features, investigations and imaging techniques.

Procedures

Pre- and postoperative intravenous urography, and preoperative ultrasound and plain x-ray of the kidney were done preoperatively for all patients. PCNL surgery was initiated after giving patients general anesthesia in the lithotomy position and inserting a 6 F open-end ureteral catheter via cystoscopy. PCNL was conducted by a urologist and included percutaneous puncture of the pelvicalyceal system, arrangement of the tract and the fragmentation or removal of stones. At the end of the procedure, stone clearance was confirmed by endoscopy and fluoroscopy and the ureteric catheter was removed. In tubed PCNL patients, a nephrostomy tube was positioned through the Amplatz sheath and fixed to the skin and the nephrostomy was clamped for 12 hours. In tubeless PCNL, after removal of the Amplatz sheath the wound was compressed for two minutes and then sutured with one-stitch non-absorbable suture followed by dressing without insertion of a nephrostomy tube.

Statistical methods

Statistical analysis was implemented using SPSS version 20. For analysis of categorical variables, chi-square and Fisher's exact tests were applied; for continuous variables, the independent sample t-test was used. P=0.05 was considered to indicate statistical significance.

Ethical considerations

Ethical considerations were included a written informed consent from each patient before enrolling in the study and before PCNL surgery; approval was taken from the authorities of the Safeer Al-Imam Al-Hussein hospital (code:77331).

Results

The Mean age of group I patients was 42.76 years, which was significantly higher than mean age of group II patients of 36.54 years (p=0.01). Male gender patients in two study groups was predominant (52.9% vs. 53.3%); however, there was no significant difference between two study groups regarding gender (p=0.96) (Table 1). Postoperatively, the stone-free and residual-stone rates of group I patients were 90.2% and 9.8%, respectively, while for group II patients, they were 94.3% and 5.7%, respectively, with no significant difference between two study groups regarding the stone clearance (p=0.34). Regarding postoperative PCNL complications, no significant differences were observed between group I and group II patients in relation to postoperative bleeding (p=0.79) impaired renal function (p=0.84), organ injury (p=0.36) and sepsis (p=0.64) (Table 2). Underlying data for this study are available from Zenodo⁷.

Discussion

The current study showed a significant difference in mean age between patients with solitary kidneys and those with two kidneys. The patients with single kidneys were older than those with bilateral kidneys. This finding is consistent with the results of Basiri et al.⁸ in Iran, which reported mean age of 42.1 years for single kidney in comparison to 38.5 years for double kidneys. No significant differences were observed between our study groups regarding gender, although the male patients were more than female patients. These findings are similar to previous Iraqi studies^9,10.

The preoperative and intraoperative characteristics of both study groups patients were not significantly different. These findings agree with results of many prior studies like those of Yaycioglu et al.¹¹ in Turkey and Agrawal et al.¹² in India. PCNL intraoperative difficulties might be observed among patients with solitary kidney like some problems in PCNL approach and tracts¹³.

Analysis of postoperative outcomes showed no significant difference in clearance rate between patients with single and bilateral kidneys (p=0.34). Similarly, Haberal et al.¹⁴ revealed that the postoperative stone free rate was similar for both solitary and bilateral kidneys. The postoperative complications were not significantly different between both study groups. This finding coincides with the results of Wong et al.¹⁵ in the UK and Akman et al.¹⁶ in Turkey, which documented that PCNL is a safe procedure for patients with solitary kidney with acceptable complication rates.

To conclude, PCNL is effective and safe for treatment of renal stones of patients with single functioning kidney.

Data availability

Zenodo: Safety and efficacy of percutaneous nephrolithotomy. https://doi.org/10.5281/zenodo.2872778⁷.

This project contains raw data for each patient assessed in this study.

Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).