From the Guidelines
For a renal calyx stone measuring 4x5 mm with a density of 800 HU, flexible ureteroscopy with laser lithotripsy and endoscopic stone extraction is the preferred treatment option over ESWL. This recommendation is based on the most recent and highest quality study available, which suggests that for symptomatic patients with a total non-lower pole renal stone burden ≤ 20 mm, clinicians may offer SWL or URS, but URS is associated with a lower likelihood of repeat procedure 1. The stone's size of 4x5 mm is well within the range that can be effectively managed with ureteroscopy, and the density of 800 HU, although not extremely high, may still pose challenges for ESWL, especially considering that stones with densities above 1000 HU typically respond poorly to ESWL. Some key points to consider in this decision include:
- The success rate of URS is less dependent on stone composition, density, and location compared to SWL 1.
- URS offers a higher stone-free rate and a lower likelihood of repeat procedures compared to SWL for stones in this size range 1.
- The procedure typically requires general anesthesia and is performed as a day surgery with a short recovery period.
- A ureteral stent might be placed temporarily after the procedure to ensure proper drainage. The final treatment decision should be made after considering other factors including the patient's overall health, anatomy, previous stone treatments, and personal preferences.
From the Research
Renal Calyces Size and Treatment Options
- The size of the renal calyces is 4x5 mm, with a non-obstructing density of 800, which may be suitable for treatment with flexible ureteroscopy and laser lithotripsy 2, 3, 4, 5.
- Studies have shown that flexible ureteroscopy is a viable option for treating renal stones 2 cm or greater, with high stone-free rates and low morbidity 2, 4, 5.
Flexible Ureteroscopy and Laser Lithotripsy
- Flexible ureteroscopy with holmium laser lithotripsy has been shown to be effective in treating large renal stones, with stone-free rates ranging from 79.1% to 93.3% 2, 3, 4, 5.
- The use of ureteral access sheaths and high-power lasers has become popular among practitioners, with many considering flexible ureteroscopy as a first-line treatment modality for renal stones, especially those <2 cm 6.
Stone Size and Location
- The stone size and location can affect the stone clearance rate, with lower calyx calculi and multiple calyx calculi having lower clearance rates 5.
- The final stone-free rate decreases as stone size grows, with a stone-free rate of 58.3% for kidney stones larger than 4 cm after an average of 2.3 procedures 5.
Treatment Outcomes
- Flexible ureteroscopy and laser lithotripsy have been shown to be safe and effective for the treatment of renal stones, with low complication rates ranging from 15.1% to 29.1% 3, 5.
- The most common complication is postoperative fever, with some patients requiring blood transfusion due to postoperative coagulation disorders induced by urosepsis 5.