Stone prevention and advancements in stone practices

Glenn M. Preminger, MD

Kidney stones are a common condition in urologic patients, resulting in high rates of morbidity. As obesity numbers increase around the world, many urologists wonder whether kidney stones can be prevented and if so, what patients can do to help inhibit the stone-forming process.

At the 2021 American Urological Association annual meeting, Glenn M. Preminger, MD, presented the John K. Lattimore Lecture, “Kidney Stones: Is Prevention Possible?” In his presentation, he discussed innovations in the medical management of recurrent nephrolithiasis. Preminger is Professor of Urologic Surgery and Director of the Comprehensive Kidney Stone Center at Duke University Medical Center, Durham, North Carolina.

How much of your time with patients is spent discussing prevention of stones?

Our practice primarily involves management of stones, and while we spend a considerable amount of time with endourologic stone removal, at least 50% of our time is spent with evaluation and ultimately, the medical prevention of our patients with stone disease. Even in patients that have only been single stone formers, especially those that have required surgical stone removal, we believe that medical stone management is warranted to prevent recurrent stones.

What are the challenges to preventing stones?

The challenges involved in medical stone prevention are first, making the diagnosis with current protocols. It's relatively easy if we can get the patient to perform two random 24-hour urine collections. Second, the hardest part is having the patient sign on to the program to increase their fluids, to potentially change their diet and, in the majority of individuals, to start them on medical therapy. And so, compliance with the regimen of both conservative measures and selective medical therapy is the hardest part of medical stone management. But once the patient is compliant with our treatment plan, and we can build these recommendations into their normal routine, we find that this form of selective medical stone management is not a significant burden for the patient.

How has your stone practice evolved over the past 3 to 5 years? What advances do you anticipate in the next 3 to 5 years?

Our practice has evolved in that many of the urologists in the community and out in practice are now a lot more familiar with medical stone evaluation and selective medical management. So, we find that the "routine stone formers" are now being managed out in the community, and our practice primarily deals with somewhat complicated patients, both surgical and medical. From a medical standpoint, these will be individuals who have been started on medical therapy and have not responded. We find that with some “fine tuning” of their medical management, we can usually get their stone disease under control.

From a future standpoint, one of the exciting things now in medical stone management has to do with the genomic evaluation of patients with stone disease. We're now finding that certain patients, such as those with renal tubular acidosis, cystinuria, or hyperoxaluria might have a monogenic cause of their stone disease. There are some very exciting studies that are currently underway, demonstrating the ability to genetically modify our patients’ risks for recurrent stone formation.

Is there a multi-specialty component to stone prevention? If so, what is the ideal way this should work?

For complete stone prevention, there needs to be a multi-specialty or a multi-disciplinary approach in that we need to treat the patients both surgically and medically if we want to prevent recurrent stones. At our institution, urology controls both the surgical management and medical stone prevention, but this would be something dependent upon the situation at your particular hospital, whether you have the expertise or the interest to do the medical evaluation and prevention of your patients with recurrent stones, or whether you employ the help of mineral metabolism, nephrology, or another group, perhaps dietary individuals. So, I believe you need to treat your patients with stones, both medically and surgically, and depending upon your expertise, that will determine how multi-disciplinary your stone prevention practice becomes.