Mini-PCNL according to Lahme for kidney stones

Mini-PCNL is the abbreviation for minimally invasive percutaneous nephrolitholapaxy. It is an operation to remove larger kidney stones in which, after the stone has been broken up with a laser, all fragments are removed from the kidney through a tube. Mini-PCNL is performed with a miniaturised instrument that has only approx. 20% of the cross-sectional area of the conventional nephroscope. This makes Mini-PCNL considerably gentler and less prone to complications.

The guidelines of the national and international urological societies recommend PCNL for stones with a diameter of 2 cm or more. However, depending on the location and other circumstances, Mini-PCNL can also be performed for kidney stones from 1 cm.

Yes. Mini-PCNL can be performed on children from the age of 6 months up to very elderly patients. The method can also be used for most positional anomalies of the kidneys, for example the so-called horseshoe kidney. Mini-PCNL is only inadvisable in patients with a blood clotting disorder.

Mini-PCNL is performed with a miniaturised nephroscope that has a diameter of <4 mm. The standard nephroscope has a diameter of approx. 8.5 mm. The cross-sectional area of the standard nephroscope is therefore approx. 5 times larger. Thanks to miniaturisation, access to the kidney is less dangerous and the risk of complications, such as bleeding, is significantly lower. In Mini-PCNL, the stones are broken up with the laser so that they only need to be flushed out. In standard PCNL, the stone fragments typically have to be pulled out with grasping forceps.

Under ultrasound guidance, the collecting system of the kidney is punctured with a thin needle. Under X-ray control, after a guide wire has been inserted, the puncture channel is widened so that a tube can finally be inserted. The mini-nephroscope is advanced through this tube into the collecting system of the kidney and the urinary stone treatment is carried out.

With Mini-PCNL, a stone-free rate of approx. 95% can be achieved. As a rule, only one operation session is required. For larger kidney stones that affect several renal calyces, a second puncture may be necessary in the same session. Mini-PCNL is therefore one of the kidney stone treatment methods with the highest success rate.

The most common risk of Mini-PCNL is a febrile inflammation in approx. 7% of cases, which requires antibiotic treatment. Blood in the urine may occur temporarily. Serious bleeding during Mini-PCNL is very rare with an experienced surgeon.

In contrast to other methods of urinary stone treatment, Mini-PCNL requires special experience. As the kidney is one of the organs of the body with the best blood supply, the procedure must be well thought through in advance. High-resolution ultrasound and a modern, digital X-ray machine with optimal image quality and low radiation exposure are also important for a low surgical risk.

The Mini-PCNL is performed on the day of admission. A kidney catheter and a bladder catheter are inserted to drain urine after the operation. The bladder catheter is removed on the first day after the operation and the kidney catheter on the second day. Patients are usually discharged from inpatient treatment on the third day after the operation. Pain is not to be expected after Mini-PCNL. If necessary, painkillers can also be given. An outpatient follow-up examination approx. 1–2 weeks after discharge from inpatient treatment is advisable.