To explore the safety and effectiveness of the "Φ-shaped " resection in lateral position in percutaneous nephroscope plasma electrode deroofing of renal cysts.

A retrospective analysis of the data of 31 patients with dorsal renal cysts treated in the Affiliated Southeast Hospital of Xiamen University from February 2017 to May 2021. Patients took the lateral position, surgeons used color Doppler ultrasound to guide the puncture needle into the cyst cavity, placed the guide wire, withdrew the needle, inserted the 22 F peel-away sheath and percutaneous nephroscope, then checked whether the cyst cavity was connected to the renal pelvis and identified the cyst wall and renal parenchyma plasma electrodes were inserted into the boundary line of the sac, and the capsule wall was cut to the junction or the thickening of the sac wall at 12 and 6 o’clock respectively. From 6 o’clock, it was cut to the 12 o’clock direction along the left arc along the boundary line, the same method cut the right side of the capsule wall, the overall cutting path was in the shape of "Φ". Without further dissociating the cyst wall, the left side of the puncture point was taken as the clamping site, and the left half of the cyst wall was pulled out of the body while rotating, and the right side was treated in the same way. Check for bleeding, if necessary, electrocoagulation to stop the bleeding. The indwelling drainage tube was unsheathed. Postoperative reexamination of the cyst cavity was more than 50% smaller than before meaned the operation was effective.

One case was diagnosed as renal calyx diverticulum during the operation. The operations of the remaining 30 patients were completed as planned. The operation time was 15-52 min without complications. Followed up for 3-12 months, there was no obvious recurrence.

During the treatment of dorsal simple renal cyst with percutaneous nephroscope plasma, the modified "Φ-shaped" resection method in lateral position is safe and effective, and it is convenient for anesthesia management. The scope is separated, the surgical specimen can be taken out completely.