Super Mini-Percutaneous Nephrolithotomy in Pediatric Stone Disease

Abstract

Introduction:

Super mini-percutaneous nephrolithotomy (PCNL) (SMP) has been described to be used for stones up to 2.5 cm in size, but is especially practical for stones unsuitable for extracorporeal shockwave lithotripsy (including cysteine and calcium phosphate stones) or those with difficult anatomy. SMP can be used alone, replacing retrograde intrarenal surgery, or in combination with standard PCNL. Lithotripsy is performed by holmium YAG laser and the stone fragments are cleared by a powerful built-in suction. ^{1 –3}

Materials and Methods:

In this video we demonstrate two SMP systems, Hawk^® and the Clear-Petra Wellead^®. The two different systems are illustrated using the eight SMPs undertaken in 2017–2018 in seven children, aged 3–15 years, four Hawk and four Clear-Petra-Wellead for stones of size 6–18 mm.

Technique:

The following technique was used: After initial cystoscopic insertion of a 5F-Pollack ureteral catheter (Cook^®) over a 0.035F sensor guidewire (Boston Scientific^®) and urethral catheterization, the patient was positioned prone supported by gel pads. A bolster was placed under the relevant pole of the kidney to elevate it. Measures to prevent hypothermia should be rigorously adhered to, such as, warmed operating theaters, use of irrigation and intravenous fluid actively warmed to body temperature, and avoidance of pooling of fluid on or under the patient by use of water-proof sticky drapes. The desired calix is accessed under ultrasound guidance using a 5F Kellett needle (Cook). The 0.035 Terumo Radifocus^® guidewire was exchanged to a 0.035 sensor, Boston Scientific^® guidewire and was advanced down the ureter. The needle was removed over the guidewire and the tract was serially dilated to 14F under fluoroscopic control. A second guidewire (0.035 Sensor; Boston Scientific) was placed through a 10F flexi-tip dual lumen ureteral catheter (Cook) to secure the tract. The Y-shaped sheath was inserted and connected to the negative pressure aspirator. For advancement of the Clear-Petra Sheath within the pelvicaliceal system, the trocar should be replaced to avert infudibular injury. Nephroscopy is performed using a 7F nephroscope for the Hawk system and a 6/7.5F semirigid ureteroscope (R. Wolf^®) for the Clear-Petra. Lithotripsy was performed by holmium-YAG-laser (Cook) using a high-frequency low-energy setting. With the sheath tip placed in proximity, stone fragments were cleared through suction connected to the short arm of the Y-sheath in both systems. In the absence of hydronephrosis or hematuria because of the small tract, SMP was undertaken tubeless and the patient can be discharged on the second postoperative day. Alternatively, if there was some hematuria, a nephrostomy will be left in situ until the hematuria has cleared, to avoid clot colic or obstruction.

No competing financial interests exist.

Runtime of video: 4 mins 13 secs

This video was presented at the ESPU 2019 Congress (European Society for Paediatric Urology).