After extracorporeal shock-wave lithotripsy (ESWL), the time needed for stone expulsion depends on the size and hardness of the fragments. In most cases, passage begins only after one day; soft stones may be expelled on the same day.
Although ESWL can break the stone into pieces, these pieces are still discrete fragments. They have to be flushed out by drinking plenty of water and urinating frequently. The recommended fluid intake is 2 000–3 000 mL per day. Patients are also advised to walk around so that the fragments can migrate and be expelled more easily. A small portion of the fragments starts to come out one day after the procedure, and the bulk of the material is then passed gradually; in general, the majority of fragments clear within one day. Large or hard stones may not be completely disintegrated by a single session; a second lithotripsy one week later may be required, and only after the stone is reduced to fine gravel can complete expulsion occur.
During the passage period, mild abdominal pain and sometimes haematuria are normal; increasing fluid intake is usually sufficient.
| Item | Details |
|---|---|
| Onset of expulsion | Usually begins ≥ 1 day after ESWL; soft stones may pass same day. |
| Mechanism | Fragments are flushed by high fluid intake (2–3 L/day) and physical activity (walking). |
| Time-course | First fragments appear after 24 h; majority clear within 1 day if complete fragmentation achieved. |
| Hard/large stones | May require a second session 1 week later; only after further breaking can all fragments pass. |
| Expected symptoms | Mild abdominal pain, transient haematuria; managed by increased oral fluids. |