Why can't the stone be seen after lithotripsy for ureteral calculi?

Possible reasons for not seeing the stone after lithotripsy for ureteral calculi include: 1. Small stone fragments: After lithotripsy, the stone may break into tiny particles or crystals. These minute fragments can be difficult to see with the naked eye as they pass in the urine, possibly only causing urine turbidity. 2. Stone impaction: Sometimes, the stone may remain impacted at a narrow segment of the ureter and fail to fully pass out, making it unobservable. 3. Sedimentation at the bottom of urine: The crushed stone fragments may settle at the bottom of the urine container during urination. If the urine is not carefully examined, these fragments might be missed. 4. Hard stone composition: If the stone is particularly hard or irregularly shaped, it may not be completely fragmented and could remain lodged in the urinary tract, thus not visible externally. To confirm complete stone passage, patients are advised to undergo follow-up ultrasound examination at the hospital after lithotripsy. Additionally, drinking plenty of water and engaging in moderate physical activity can help facilitate stone expulsion.