Removal of small asymptomatic kidney stones during endoscopic ureterectomy or contralateral stone removal significantly prolongs the time to recurrence compared with leaving asymptomatic stones in a randomized trial.
The mean time to recurrence with removal of asymptomatic stones was approximately 4.5 years, while the mean time to recurrence without removal was approximately 2.5 years (P
When the stone growth rate was excluded from the sensitivity analysis, the rate of the recurrence control group remained significantly higher. Dr. Michael R. Bailey of the University of Washington in Seattle and co-authors in New England Journal of Medicine.
“Our Prospective Randomized The trial results support surgical removal of small, asymptomatic kidney stones to remove symptomatic stones,” the authors said of their findings. “Removal of small asymptomatic kidney stones is a common surgical decision that currently lacks specific guidelines and may involve hundreds of thousands of surgeries each year in the U.S. alone. Removing small asymptomatic kidney stones at the time of surgery requires additional A primary stone in 25 minutes…should be weighed against the need for reoperation in 63% of patients with recurrence.”
A financial comparison showed that, in the authors’ point of view, $36 per minute would make The cost of 100 surgeries increases by $90,000. On the other hand, the cost of 63 emergency room visits was estimated at $217,000.
According to the authors of the accompanying editorial, the results are not surprising, but the trial is still worthwhile. Modern urological techniques and techniques from experienced endoscopists contributed to the success of the trial, said David S. Goldfarb, MD, of the New York Harbor Veterans Affairs Healthcare System and NYU Langone Health in New York City.
The trial results leave several unanswered questions. Can prevention strategies apply equitably to the majority of patients with asymptomatic stones? Can a general urologist also perform a procedure with the same results? Does the number of asymptomatic stones affect the outcome? Would increased use of preventive medication (only 25% in this study) change the results?
“Finally, and most provocatively, when should an asymptomatic stone be removed endoscopically – only if the primary stone is present if there is an obstructing ureteral stone or a large one in the kidney , asymptomatic stones, as covered by this protocol?” Goldfarb asked. “Asymptomatic stones are often found and surgery is not recommended in most cases.”
“It is conceivable that elective excision would allow these patients to avoid the pain and trauma, inefficiency and expense of the emergency department. Expensive doctor visits, infections, receiving pain medication and additional imaging tests,” he added. “The alternative to preemptive surgical intervention is to finally figure out how to get these small stones to dislodge and pass spontaneously.”
This prospective, multicenter study addresses whether endoscopic stone resection is performed or not. This long-standing problem. For symptomatic stones, small asymptomatic kidney stones at surgery would be beneficial. Bailey and co-authors say relevant U.S. and European clinical guidelines are ambiguous on the issue.
Multiple studies have shown that patients with asymptomatic stones have a 50% chance of recurrence within 5 years of surgery for symptomatic stones. However, the only prospective study cited by the guideline authors evaluated shock wave lithotripsy for asymptomatic stones and favored 1-year observation.
To provide prospective data to guide decision-making, researchers recruited 75 adults planning to undergo endoscopic surgery (ureteroscopy or percutaneous nephrolithotomy) for primary stones patient. Patients were randomized to undergo ureteroscopy or observation (control group) to remove secondary (asymptomatic) stones. Postoperative CT was performed 90 days and 1 year after the intervention.
Patients were followed up to 5 years at 3-month intervals. Median follow-up was 4.2 years. The primary outcome was a composite of ED visits related to stones on the same side of the original surgery, subsequent surgery for stones on the test side, or new secondary stone growth. Secondary outcomes included operative time to remove asymptomatic stones, ED visits within 2 weeks after surgery, and patient-reported stone passage or new stone growth.
All but two patients were included in the primary and secondary outcomes. The data showed that 6 of 38 patients in the treatment group relapsed, compared with 22 of 35 patients in the control group. The absolute difference of 47 percentage points exceeds the 35 percentage points used for statistical power calculations.
After excluding stone growth as a marker of recurrence, the median time to recurrence remained significantly longer in the on-treatment arm (1,717.1 days vs 1,262.8 days). Four patients (11%) in the treatment group and 15 patients (43%) in the control group had an emergency department visit or additional surgery.
The additional operative time required for asymptomatic stone extraction was 25.6 minutes, accounting for 27% of the total operative time (93.6 minutes vs 59.8 minutes in the control group). The additional time for ureteroscopy was an average of 25.0 minutes, while the average time for percutaneous nephrolithotomy was 30 minutes.
Stone passage was reported in 8 patients in the treatment group and 10 patients in the control group. Seven in the treatment group and six in the control group reported asymptomatic stone or fragment discharge. New stone formation occurred in 14 patients in the treatment group (mean duration of treatment, 1,338 days) compared with 13 patients in the control group (1,381 days).
Charles Bankhead is the Senior Editor in Oncology, which also covers Urology, Dermatology, and Ophthalmology. He joined MedPage today in 2007. focus on
The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases and the Department of Veterans Affairs Puget Sound Health Care System.
Goldfarb discloses relationships with Alnylam Pharmaceuticals, Cymbay, Dicerna, Moonstone Nutrition, Sumitovant, Synlogic and Travere Therapeutics, and patient/royalty/IP interests.