Role of Endourological Procedures (PCNL and URS) on Renal Function: A Systematic Review

Kidney stone disease (KSD) prevalence is rising and therefore endourological operations such as percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS) are increasingly performed. Kidney function can be impaired as a result of the disease, urinary infections, ureteric obstruction related to the stone or surgical intervention. While it is generally believed that treatment of KSD would lead to an improvement in renal function, there is a theoretical risk that both PCNL and URS will have an adverse effect. PCNL requires physical puncture of the renal parenchyma and URS often requires high-pressure irrigation with potential heat-related damage from laser application to stones. We, therefore, conducted a systematic review to examine the effect of PCNL and URS on renal function.

During our search we identified 28 studies for inclusion. PCNL was assessed in 21 studies including 1994 patients, URS in four studies including 608 patients, and four studies comparing PCNL and URS including 262 patients.

For patients undergoing PCNL, the majority of studies showed either improvement or trend to improvement in postoperative renal function. Only one study showed postoperative worsening and they measured renal function only on day 1 after PCNL. In three studies, the number of punctures was shown to predict deterioration and this supports the idea that the parenchymal damage required causes a decline in function. Patient comorbidities including hypertension, diabetes, and pre-existing poor function were identified as potentially important factors in predicting deteriorating renal function. This suggests that deterioration in renal function is determined by alternative underlying pathological processes.

Following URS, the overall trend was that renal function improved postoperatively and interestingly, a study found no association between multiple procedures and poor postoperative renal function. As with PCNL, one study showed that if preoperative renal function was abnormal then it had a tendency to deteriorate, but if it was normal preoperatively it remained normal postoperatively.

Our review suggests that endourological interventions do not adversely affect renal function and tend to improve it in patients who do not have a poor renal function prior to the procedure. Several factors including poor preoperative renal function, diabetes, hypertension, and multiple percutaneous tracts appear to predispose patients to declining renal function after procedure. These patients should be counseled for and followed up appropriately.

Written by: Bhaskar Somani, MRCS, FEBU, DM, FFSTEd, FRCS (Urol), and Thomas Reeves, MD, Professors of Urology, University Hospital Southampton NHS Foundation Trust, Southhampton, UK

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