The role of intraoperative intrarenal pressure in the postoperative period of percutaneous nephrolithotripsy in patients with urolithiasis.

Introduction. Percutaneous and endourological surgeries are the most common interventions for nephrolytiasis in urologists’ practice. During the operation, it is important to maintain the right balance between sufficient flow of irrigation fluid for adequate visualization and safe intrarenal pressure. Intraoperative increase in intrarenal pressure is associated with the development of purulent-inflammatory complications in the postoperative period. The aim of the study. To substantiate the expediency of intraoperative monitoring of intrarenal pressure, as well as to assess the risks of postoperative complications after percutaneous nephrolithotripsy. Materials and methods. The study included 250 patients with staghorn kidney stones. In the first group (n=120) percutaneous nephrolithotripsy (PCNL) was performed according to the standard procedure with a puncture canal diameter of 30-32 Сh. The second group included 130 patients who underwent percutaneous nephrolithotripsy using a mini nephroscope (mPCNL) with a working channel diameter of 16 Ch. To achieve the aim of our study, we have developed a method for determining intrapelvic pressure, implemented using a miniature pressure sensor, which is installed directly into the pelvis at the time of the calycopelvical system puncture. During the surgery, the intrapelvic pressure was constantly monitored according to the method we proposed. Results. The lowest values of intrapelvic pressure were recorded when performing PCNL with the installation of an Amplatz sheath exceeding the size of the nephroscope by 2 or more Ch. When performing mPNLT, the installation of a ureteral catheter allows minimizing the increase in intrapelvic pressure. Hyperthermia in the postoperative period significantly depends on an increased intrarenal pressure and the presence of an infectious agent in the renal system. Separately performed urine cultures from the pelvic and bladder with obstruction of even minimal severity may have significant differences. In patients of mini-PNLT group intraoperative intrapelvic pressure was significantly higher (p≤0.05). The frequency of fever and exacerbation of calculous pyelonephritis is significantly higher in group of standart PNLT (p < 0.05), which is explained by greater traumatization of the renal parenchyma when creating a working fistula. Conclusion. The proposed method allows the most accurate intrasurgery monitoring of intrarenal pressure during minimally invasive surgical treatment of kidney stones in order to minimize the frequency of infectious and inflammatory complications.