INTRODUCTION
Kidney stone disease is one of the most common urinary system diseases. It has a recurrence rate of up to 50% within five years [1]. Different treatment methods are available in patients with kidney stones according to the size and location of the stone. There are treatment alternatives in kidney stones, such as stone fragmentation with extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PNL), and retrograde intrarenal surgery (RIRS). PNL is a method of removing stones by first fragmenting them with lithotriptors after percutaneous entry into the kidney. Percutaneous access to the kidney was first reported in 1955 by Goodwin et al., and the first PNL procedure was described by Fernström in 1976 as a treatment option for kidney stones [2; 3]. However, with the introduction of ESWL in the early 1980s, the use of PNL has decreased but it can be an appropriate treatment method, especially for treating large or multiple kidney stones and stones located in the lower calyx [4]. The European Association of Urology (EAU) guidelines also recommend PNL as the first option in the treatment of kidney stones larger than 2 cm [5]. RIRS is the name given to the process of fragmenting the stone with a laser accessing the kidney through the ureter with a flexible ureterorenoscope. This technique has the advantages of using natural methods and patients requiring shorter hospital stay in the postoperative period. The success of RIRS is related to the size, hardness and location of the stone [6].
When kidney functions are impaired, blood urea and creatinine levels increase, but this may occur hours, even days later. Some markers are used in urine and blood to detect kidney dysfunction earlier. Among the markers that have been shown to be effective in determining kidney damage are some urinary enzymes [7], cystatin C, urine cytokines; myo-inositol oxygenase (MIOX), and kidney damage molecules [e.g., kidney injury molecule-1(KIM-1)] [8; 9].
Although there is no specific blood marker showing kidney damage, KIM-1 is released at high rates in proximal tubular cells after this damage. Although KIM-1 is mostly used as a urine marker for kidney damage, it has been revealed that it can also be detected in the blood to detect kidney injury [10; 11].
Gaut et al. used the Western blot technique and reported that the increase in myo-inositol oxygenase (MIOX), which has been demonstrated to be specific to proximal renal tubules, occurred approximately two days before the increase in the serum creatinine level in kidney damage, and therefore it can be used as a potential early diagnosis sign for acute kidney injury [12].
In this study, we aimed to reveal the possible acute kidney damage caused by these surgical techniques by measuring plasma KIM-1 and MIOX levels at the preoperative and postoperative fourth hour in patients who underwent PNL and RIRS, and to compare these two techniques in terms of these parameters.
MATERIAL AND METHOD
This study was conducted at the urology clinic of Erzincan Binali Yıldırım University between November 15, 2018 and February 15, 2020 in accordance with the principles of the Declaration of Helsinki, patient rights regulation and ethical rules, after receiving the ethics committee approval (numbered33216249_604.01.02.E.49628, dated November 9, 2018). Eighty patients scheduled for PNL or RIRS in our urology clinic were included in the study. The patients were informed about the study in advance, and their consent was obtained for participation in the study.
The patients’ age, gender, operation time, operation side, stone location, stone size, kidney entry points (in the PNL group), presence of postoperative residual stones, and length of hospital stay were recorded. Three patients were excluded from the study due to solitary kidney, 4 due to renal dysfunction, 1 due to skeletal deformity (scoliosis), and 1 due to ectopic kidney.
Preoperative complete blood count analysis, serum urea analysis, biochemical tests containing creatinine and blood parameters, posterior-anterior chest radiography, ECG, serological tests, and urine culture analysis were performed in all patients. In the postoperative period, complete blood count and urea creatinine values ​​were examined again. In order to reveal the presence of residual stones, non-contrast computed tomography was performed one month after the operation, and stones smaller than 4 mm were accepted as clinically insignificant residual fragments (CIRFs). Complete stone-free status and CIRFs were considered to indicate operative success. The Clavien classification was used to evaluate the complications that developed.
Venous blood samples were taken preoperatively and four hours after the operation from each patient who underwent surgery in our service and were included in the study. These samples were centrifuged and stored at -80 °C.