Grading system for percutaneous nephrolithotomy complications found viable

Jul 01, 2010

A prospective, standardized system that has been used to report complications of several urologic procedures can also be utilized for reporting complications during percutaneous nephrolithotomy.

Key Points

Barcelona, Spain-A prospective, standardized system that has been used to report complications of several urologic procedures can also be utilized for reporting complications during percutaneous nephrolithotomy (PCNL), a team of Romanian researchers reported at the European Association of Urology annual congress here.

A podium presentation at the meeting described one of the first series to examine PCNL complications using the modified Clavien grading system, which is becoming the standard metric for reporting surgical complications.

The system divides postoperative complications into five grades. Grade 1 complications are deviations from the normal postoperative course, while grade 2 complications require pharmacologic treatment. The more serious complications require more invasive treatments: Grade 3 complications require surgical intervention and grade 4 are life threatening, necessitating an intensive care unit stay. Postoperative mortality is a grade 5 complication.

"We wanted to introduce the modified Clavien system as a standard for reporting PCNL outcomes," said co-author Razvan Petca, PhD, extern collaborator at the Burghele Clinical Hospital in Bucharest. "Considering that it is already standard for other genitourinary procedures, we wanted to incorporate it into the field of PCNL. The broad implementation of this classification may facilitate the evaluation and comparison of surgical outcomes among different surgeons and centers."

Dr. Petca and colleagues began a prospective registry of complications using the modified Clavien system. They reported data on 417 prone PCNLs performed in a single year.

The overall complication rate was 33%, with 109 minor complications (grades 1 and 2) and 43 major complications (grades 3 to 5). The most common complication in these patients was fever, and the most common surgical intervention required was the placement of a double-J stent.

Higher rates for multiple calyces

The researchers found that the complication rates were higher among patients with complex stones involving multiple calyces and among cases with a longer operative time.

"We only have rigid instrumentation at our hospital, which requires more tracts than would be necessary if we had flexible instruments," Dr. Petca explained.

Indeed, 24% of the PCNLs in his series used more than one access site. This may have resulted in a higher complication rate than in centers that have access to flexible instrumentation. Over 40% of the patients underwent tubeless PCNL, where patients do not have a nephrostomy tube placed at the end of the procedure. There were no differences in the complication rates of patients undergoing tubeless compared to standard PCNL.

Also notable was that the study was performed in a prospective manner by completing a survey about complications immediately prior to a patient's discharge from the hospital.

"We had previously collected complication data retrospectively and found that our rates were considerably higher when we switched to a prospective system," Dr. Petca said.

The modified Clavien system "proved relevant to both prognosis in individual cases and to the standardization of outcome reporting," he and co-authors concluded.

Dr. Petca strongly encouraged adoption of the system across academic institutions to help inform patients about their risks and to aid in comparing surgeons and centers.