ESWL: A Forgotten Tool

First, the doctors discuss ideal candidates for ESWL. Dr. Nakada considers 2 centimeters as the maximum stone size for ESWL. The stone must be low density (<1000 Houndsfield units) on CT, and the skin-to-stone distance must be less than 10 centimeters. Other contraindications to ESWL include patients with coagulopathy and patients with a solitary kidney. Dr. Nakada mentions that PCNL and a trial of passage are more common treatments for kidney stones. He also emphasizes the importance of continual stone analysis because stone composition can change over time, thus changing the probability that ESWL will work. He prefers to observe patients in their 70’s / 80’s and patients with calyceal stones. He also mentions that it is important to mention the higher failure rates of ESWL when compared to other treatments in the initial discussion with the patient.

Next, Dr. Nakada describes his ESWL technique. He continues to deliver shock waves to the stone until he cannot see it with fluoroscopy. For obstructing stones, he gives contrast to check for complete fragmentation. Additionally, he mentions that urologists might have to wait 6-8 months after the procedure for the patient to pass their stones, so the conventional 3 months is not a good benchmark for re-treatment. If there is one fragment that is too large to pass, he will perform a second lithotripsy. He states that there is no role for a third lithotripsy.

Next, Dr. Silva and Dr. Nakada discuss why ureteroscopy has eclipsed ESWL. They come to the conclusion that more residents are trained to do PCNL, there is a strict criteria for ESWL, and heavier patients usually cannot meet the skin-to-stone distance. The doctors then discuss imaging for kidney stones and Dr. Nakada notes that ultrasound is unreliable to gauge stone size. Although he always gets a CT scan without contrast before the procedure, a postoperative CT scan may be difficult to obtain because of cost limitations.

Finally, the doctors discuss their post-procedural recommendations. Dr. Nakada sends all his patients home with Flomax and a single dose of antibiotics. He avoids narcotics and NSAIDs and recommends Tylenol. FInally, he schedules a follow-up KUB 2 weeks after the procedure.