Assessment of the Effects of Access Count in Percutaneous Nephrolithotomy on Renal Functions by Technetium-99M-Dimercaptosuccinic Acid Scintigraphy

Total 37 patients who had undergone PCNL were included between June 2007-June 2009. All patients were evaluated routinely with physical examination, complete blood count (CBC), blood urine nitrogen (BUN), creatinine levels, and urinalysis. None of the patients had experienced pyelonephritis, and none had a solitary kidney, renal ectopy or history of any other urinary abnormality. At least one of the following techniques; namely computed tomography (CT), intravenous urography or ultrasonography, was preferred routinely before surgery in order to visualize the urinary system. Unilateral PCNL was performed in all patients. Postoperative CBC and BUN creatine levels were repeated.

Preoperative DMSA scans were performed a day before the surgery, whereas postoperative scans were randomized to indicate early and late term. The aim of randomization was to determine an optimal time for assessing patients. A DMSA scan was read by using a technique that divides both kidneys into three paired poles. In addition the uptake of all opposite poles was measured together and calculated as a percentage value separately (Figure-1), e.g., the two upper poles' uptake was measured together as if they were renal units and each poles' own portion in this total uptake was declared separately as a percentage. How the differential functions were changed between the sides undergoing PCNL and the opposite sides, as well the changes before and 6 months after surgery are manifested by using these parameters.

Twenty six of 37 cases underwent PCNL with a single access site (70.3%) and 11 separately with multiple accesses (29.7%). When each of the poles of a kidney was considered as a surgical unit, there were 51 units. In this manner the functional change of a unit would show the surgical trauma inflicted on the poles by PCNL access.