[Endoscopic marsupialization of parapelvic renal cysts]

Parapelvic renal cysts are very common. Indications for surgical treatment are upper urine tract obstruction, pain and recurrent gross hematuria.

To analyze the efficiency and safety of endoscopic transurethral and percutaneous laser marsupialization of parapelvic renal cysts.

A total of 9 patients were undergone to transurethral intrarenal marsupialization of parapelvic renal cysts from March 2016 to February 2021 (4 men, 5 women, aged 42-78 years). Another 2 patients (2 men, aged 46 and 52 years) were treated by percutaneous approach. The average size of the cyst according to contrast-enhanced multi-slice computed tomography (MSCT) was 3.1+/-1.8 cm. In two cases, papillary tumor of the pelvis was suspected. The anteroposterior diameter of the pelvis was 2.6+/-1.3 cm; 9 patients had pain in the loin area, while in 7 patients recurrent gross hematuria was also an indication for surgical treatment. For marsupialization, a holmium (Ho:YAG) laser Auriga XL (Boston Scientific, USA) was used in 4 patients, and in other cases (n=7) a procedure was performed using a thulium fiber laser (Tm Fiber) Fiberlase U1 (IRE-Polus, Russia). In 3 patients, to clarify the site of incision of the cyst, intraoperative ultrasound was used. In all cases, after draining the cyst, an internal stent was placed inside the cyst for a period of 4-6 weeks.

The duration of transurethral surgery was 26+/-11 minutes, while percutaneous marsupialization of the cyst, which was performed in combination with percutaneous nephrolithotomy, took 10 and 18 minutes, respectively. The average catheterization time was 12+/-8 hours. Nephrostomy tube was removed on the 2nd day. The length of stay was 4+/-2 days. Febrile fever was noted in 1 patient (9%), which required a change in antibiotic therapy. During ultrasound control at discharge, the dilatation of the collecting system was not detected in any cases, while the residual cavity was found in 2 patients (18%). Follow-up contrast-enhanced MSCT and ultrasound within 3-30 months in all patients (n=11) showed no dilatation of the collecting system. In 1 (9%) patient, the residual cavity was preserved with a decrease in size to 1.2 cm without signs of upper urinary tract obstruction; the initial diameter of the cyst in this patient was 4.9 cm. There was no recurrence of gross hematuria.

In our opinion, transurethral and percutaneous laser marsupialization of parapelvic renal cysts is an effective and safe method that allows definitive treatment for cysts up to 4 cm in size. If the cyst is larger than 4 cm, endoscopic removal should be balanced with the possibility of preserving the residual cavity. The most common complication of endoscopic treatment of intrarenal cysts is acute pyelonephritis with a rate of 9%.