CT can detect rare post-percutanous nephrolithotomy complications

October 1, 2009

Major complications detected by computed tomography performed immediately following percutaneous nephrolithotomy are uncommon. However, certain major complications can be detected early.

Baltimore-Major complications detected by computed tomography performed immediately following percutaneous nephrolithotomy (PNL) are uncommon, according to an analysis of cases at five stone referral centers.

However, certain major complications can be detected early through the use of post-PNL CT imaging. Thus, in addition to defining a stone-free state following PNL, CT is useful in the post-PNL setting to inspect for surgical complications, concluded co-author Brian R. Matlaga, MD, assistant professor and director of stone disease, Brady Urological Institute at the Johns Hopkins Medical Institutions, Baltimore.

Although morbidity is far less with PNL compared to open surgery for the management of large or complex renal calculi, complications can occur. The incidence of complications, however, has not been well defined, which prompted Dr. Matlaga and colleagues to perform a multi-institutional study to better define this incidence.

About one-third (35.5%) of the patients had staghorn calculi, 36.5% had stones >2 cm, and 28% had stones <2 cm. Six renal units were ectopic, and 45.4% of the stones were predominantly lower pole.

"We wanted to get a sense of the modern landscape of the procedure and define how often we are seeing adverse developments," said Dr. Matlaga, who presented the data at the AUA annual meeting in Chicago.

"Most of the complications were minor and could be managed conservatively, but there were a few complications that were detected by CT, such as a trans-splenic nephrostomy, where postoperative care was altered based on the detection of that complication. There are certain complications that will present only on CT scan and when they're detected in a timely fashion, you can mitigate the potential damage or injuries to the patient from it, and it does affect the postoperative follow-up."

The most common complications were minor, such as thoracic atelectasis, which occurred in 44.7% of the patients. Other thoracic complications were pleural effusion (8.6%), pneumothorax (1.5%), hemothorax (1%), and hydrothorax (0.5%). Renal complications included perinephric hematoma (7.6%), collecting system perforation (2%), subcapsular hematoma (1.5%), urinoma (1%), and pseudoaneurysm (0.5%).

One trans-splenic nephrostomy was detected and two patients (1%) had ascites.

"We do not know if all post-PNL patients should get a CT scan in the immediate postoperative period because there's an increasing concern about radiation exposure from CT imaging," Dr. Matlaga told Urology Times.

"An important question is, can we obtain comparable information using less radiation exposure? That's the direction this will be going in the future."

At the least, CT in the postoperative period is most reasonable for patients with upper-pole punctures to rule out or detect thoracic or visceral complications, he said, adding: "At present, this stratification may maximize detection of procedure-related complications."