Trends favor more efficient procedures with less trauma and faster recovery.
September is Urology Awareness Month so it would seem fitting to remember that chronic and common, kidney stones affect one in 11 people.1 The National Kidney Foundation notes that each year, more than half a million people go to the emergency department for problems related to kidney stones.2 In fact, their prevalence in the United States has increased to 8.8% in the late 2000s from 3.8% in the late 1970s. The increase has occurred in both men and women, black and white individuals. In terms of lifetime risk, men experience an almost double rate, 19% compared with 9% in women. Typically, men experience their first episode after age 30; and hypertension, diabetes and obesity increase the risk.2
The past 30 years have seen dramatic change in the way kidney stones are treated with the advent of extracorporeal shock wave lithotripsy (SWL). Advances in ureteroscopic and percutaneous techniques have virtually eliminated open surgical treatments; and allowed percutaneous removal to be reserved for specific situations like resistant stones or those that are too large. Holmium laser technology has led to the widespread adoption of ureteroscopy (URS) for treating stones, as the method provides the ability to efficiently ablate the stone without causing collateral damage to surrounding tissue. Laser lithotripsy for URS is now being used the first-line treatment for kidney stones in North America in about 60% of cases.3
Today, advances in holmium laser technologies, miniaturized surgery, and disposable ureteroscopes continue to improve kidney stone surgery in a variety of ways.
IMPROVED APPROACH TO STONE REMOVAL
One example of a step forward is the new proprietary Moses holmium technology from Lumenis that has been designed to allow easier, more efficient, and potentially safer lithotripsy. The patented combination of holmium lasers and fibers significantly reduces retropulsion by optimizing holmium energy transmission. The result is less stone migration, which provides the surgeon more control, no matter the distance between the fiber and the stone. Reduced stone movement may allow for quicker procedure times and may allow for reduced, inadvertent tissue injury by giving the surgeon better control.
The Moses technology also facilitates dusting, a technique in which the advanced holmium laser delivers high-frequency, low pulse energy that pulverizes stones into particles smaller than 1 mm. The dust is eliminated through the urine. Because there is no need for repeated passes, this approach can eliminate the need for a ureteral access sheath when the stones are small. In cases of large stone volume, a ureteral stent ensures proper postoperative drainage.
MINI PERC = LESS TRAUMA
Percutaneous nephrolithotomy (PCNL) remains the surgical standard for large or complex stones. In the minimally invasive procedure, the surgeon removes the stones via a small puncture wound through the lower back. A nephroscope and other small instruments are threaded through a sheath and the stone is fragmented and actively removed, either via suction or graspers. As mini-PCNL or mini-PERC evolves, the incisions and instruments become more miniaturized, allowing the procedure to be completed through smaller holes.
A general trend in all surgery is to minimize cutting to reduce trauma, with the overall goal of fewer complications, less pain and bleeding, and a faster recovery time for patients. More evidence is needed, however, before any definitive claims can be made regarding mini-PCNL.
SINGLE-USE SCOPES INCREASE ACCESS TO CARE
Ureteroscopes are expensive, and smaller hospitals may only have one or two available. These tools are fragile, and they often require repair after a certain number of cases. This can result in patients having their surgery delayed or even cancelled.
Single-use, disposable scopes, on the other hand, can improve access to care, ensuring hospitals do not have downtime due to broken equipment. A recent study that evaluated the functionality of a single-use device versus reusable ureteroscopes found that it was comparable or superior to the reusable scopes in terms of deflection and flow, with superior cost-effectiveness.4
FUTURE
If the past 30 years are an indication of the next 30, we can expect many new innovations for kidney stone treatment. Researchers continue to investigate better approaches for recurrent occurrences. We should not forget that the cornerstone of our management must always be prevention; diet and lifestyle medication cannot be ignored. As URS methods become increasingly advanced, larger stones and perhaps more complex patients can benefit from this minimally invasive technique. Future surgery will most certainly involve robotics.
Michael E. Lipkin, MD
Associate Chief Medical Officer, Clinical Operations at Private Diagnostic Clinics, Duke University
Associate Professor of Urology, Duke University Medical Center
1. Scales CD, Smith AC, Hanley JM, Saigal CS, Urologic Diseases in America Project. Prevalence of Kidney Stones in the United States. Eur Urol. 2012;62(1):160-165.
2. National Kidney Foundation. A to Z health guide. Kidney Stones. https://www.kidney.org/atoz/content/kidneystones
3. Oberlin DT, Flum AS, Bachrach L, Matulewicz RS, Flury SC. Contemporary surgical trends in the management of upper tract calculi. J Urol. 2015;193(3):880-884.
4. DB Hennessey, G Fojecki, N Papa, N Lawrentschuk, D Bolton. Single use disposable digital flexible ureteroscopes: an ex-vivo assessment and cost analysis. BJU Int. 2018;121(Suppl 3):55-61. doi: 10.1111/bju.14235.