Refined decubitus may offer advantages during percutaneous nephrolithotomy

February 1, 2010

A South American urologist hopes to convince U.S. urologists that the Valdivia-Galdakao decubitus position offers key advantages over prone decubitus, including a higher safety margin.

Munich, Germany-For most U.S. urologists, prone patient positioning has always been considered the gold standard when performing percutaneous renal puncture, ie, percutaneous nephrolithotomy (PNL). One South American expert hopes to convince them otherwise, claiming that the Valdivia-Galdakao decubitus position offers key advantages over prone decubitus, including a higher safety margin, as shown in a recent study.

The Valdivia-Galdakao decubitus position is a further refinement of the classic Valdivia position that is gaining in popularity.

"Though the prone position remains the most popular approach worldwide, the recent resurgence of Valdivia decubitus has been a long time coming and for years has been considered by many as the choice technique when performing PNL," said Pedro Daels, MD, chief of the department of endourology at the Hospital Italiano, Buenos Aires, Argentina. "However, the rising popularity of the Valdivia may soon be eclipsed by a superior positioning with the novel intermediate dorsal decubitus, also known as the Valdivia-Galdakao decubitus."

Results showed that the colon moves away from the kidney and twelfth rib at an average of 12.9 mm and 22.8 mm more in the Valdivia-Galdakao decubitus position, respectively, than in the ventral decubitus position. The distance between the twelfth rib and the kidney did not vary with either position.

Safer percutaneous puncture

"The Valdivia-Galdakao position allows a safer percutaneous puncture as the colon slips a good inch away from the kidney puncture site," Dr. Daels said. "The proof of higher safety with this approach, as witnessed on the CT scans, should silence the skeptics who have championed prone decubitus as the choice positioning, claiming a higher risk of bowel puncture trauma in the supine position, which is simply not the case."

The advantages of the supine compared to the prone position include easier patient positioning that allows for an excellent exposure of the posterior axillary line (puncture site), sparing of contact pressure points, unrestricted respiration and unimpeded blood distribution, and easier access for the anesthesiologist in emergency cases, Dr. Daels said.

The difference between Valdivia-Galdakao and classic Valdivia decubitus is that the patient is positioned slightly more sideways, with extension of the homolateral lower limb and flexion of the contralateral at 90 degrees. This minimal lateral rotation preserves the advantages of classic Valdivia, and improves on it, according to Dr. Daels.

"As the Valdivia-Galdakao position is an intermediate dorsal decubitus of the patient, the initially ascending puncture of the classic Valdivia now becomes horizontal and, therefore, endourologist friendly," he said.

Another advantage of Valdivia-Galdakao decubitus is the single lumbar and genital sterile surgical field it creates, allowing retrograde endoscopic placement of a urethral catheter and a flank percutaneous puncture, significantly reducing surgical time. Antegrade and retrograde simultaneous endoscopic access is also possible.

"Valdivia-Galdakao decubitus allows a minimally invasive simultaneous access to the upper urinary tract and, due to its safety and versatility, it is the best option for percutaneous renal access, particularly with complex renal stones," Dr. Daels said.