MicroPERC: The logical evolution

Objective

The percutaneous approach for the renal stones larger than 2 – 2.5 cm or in stag horn lithiasis is so far been the correct indication. The next step, which led to a reduction in complications (bleeding related to the renal parenchyma and the possible, although extremely rare, perforation of the colon) it was the 'advent of Miniperc, which has led to the fragmentation of the calculation with a minimum dilation of the percutaneous route, with use of ballistic, laser or ultrasound as the source of energy. The Micronephrolithotripsy represent the logical evolution of the Percutaneous Treatment in special cases of renal stones. We present our experience on eleven patients.

Methods and results

From November 2013 to January 2014 we perform 11 interventions of Microperc. The age of patients ranged from 3 to 52 years. The procedure provides access to the kidney under ultrasound or fluoroscopic guidance, through the micro-optical system and 3-part "all-seeing needle" consisting of a needle, a spindle and a work shirt of 4.85 Fr that allows the insertion of a micro-optic (diameter 0.9mm), width viewing angle of 120° and a high resolution. A 3-way adapter is also connected to the proximal portion of the instrument for the application of an irrigation pump over that of the fiber optics and laser Holmium for the shuttering of the stones. The dimension of the stones ranged from 1.5 (2 pediatric patient) to 3.2 cm; ampullary (6 pts), lower calyx (3 pts), multiple caliceal (2 pts). In two patients with multiple caliceal stones have been completed, without difficulty or complications, respectively 2 and 3 accesses. In all cases we inserted an open tip ureteral catheter (Pollack 5.5 Fr) to drain the flow from peristaltic pump. In 3 and 4.5 y/o patients we left in situ both 6 Fr nephrostomy and 4.7 Fr ureteral stent. In the other patients we left only 4.7 Fr ureteral stent, which were removed after 15 days. All patients was discharged 2 days after the operations. 8 patients had hematuria in the first 24 hours. 10 patients was stone free at 30 days. One patient (3 cm diameter stag horn lower calyx) was subjected to a session of extracorporeal shock wave lithotripsy for the presence of two larger fragments (diameter of 6 mm and 7 mm). In one case there was serious hematuria, resolved spontaneously. The control counts and renal function after surgery was in the normal range for all patients. The operating time ranged from 2 hours (the first patient treated) and 40 minutes.

Discussion

The percutaneous nephrolithotripsy is often considered the most effective solution for kidney stones with a diameter between 2 and 2.5 cm or more, but it can sometimes present risk of bleeding of the renal parenchyma or, far more rarely, perforation of the colon. The latter has been minimized with the use of the supine position of the patient, while the bleeding still presents a possible complication. The Microperc technique is then the logical development, with the aim to reduce this complication. Also plays, and in our opinion will play more and more, a valid approach in the calculi refractory to shock waves and above all in pediatric stones. In the early stages of approach it appears to be easier to implement than the RIRS and with significantly shorter times.

References

Sabnis RB and others: Micropercutaneous nephrolithotomy (microperc) vs retrograde intrarenal surgery… BJU Int. 2013 Aug;112(3):355-61.
Di Lauro G and others: Microperc. Nostra esperienza su 10 casi… SIU 2013