How I Do It?

Management of Ureteric Stone Obstruction

In these difficult and resource-limited times, I wish to share an article that may be useful for Physicians, General Practitioners, Family Physicians, and junior doctors who treat patients with ureteric stones.

As surgeons, after years of experience, we often present and publish how we perform particular procedures at national, regional, and international conferences or in journals. In a similar way, I would like to share my approach to the management of a very common condition in Myanmar: ureteric stone obstruction. I hope this article will be practical and applicable for everyday clinical use.

Anatomy of the Ureter

First, let me remind you relevant facts about the structure of ureter.

The ureter connects the kidney to the urinary bladder. Its average length is about 10 inches.

• In larger-built Western populations, the ureteral inner  diameter is usually around 5 mm.
• In smaller-built Asian populations, it is typically narrower, around 4.5 mm. The ureter is not uniformly wide; it has three natural constrictions:
  1. At the pelvi-ureteric junction,
  2. At the level where it crosses the iliac vessels,
  3. At the vesico-ureteric junction.

Stones often become impacted at these sites, producing severe colicky pain. Such pain frequently heralds the possibility of stone passage.

One needs to know the likelihood of spontaneous stone passage

According to studies:

• Stones ≤4 mm: ~70% chance of spontaneous passage.
• Stones 5 mm: ~50% chance of passage.
• Stones 6–7 mm: ~20% chance of passage.
• Stones ≥9–10 mm: very unlikely to pass spontaneously.

When imaging (plain X-ray or CT scan) shows a stone ≥10 mm, particularly with ureteral dilatation or hydronephrosis, medical management is inappropriate. Delay in intervention risks progressive renal parenchymal loss and irreversible kidney damage.

Therefore:

• Small to moderate stones (4–8 mm) with no or only mild hydronephrosis may be managed medically.
• Moderate to severe hydronephrosis, regardless of stone size, should not be managed conservatively.

Interventional Options

If hydronephrosis is present, or if the stone is large and unlikely to pass, intervention is required:

• Ureteroscopy with laser lithotripsy
• Laparoscopic ureterolithotomy if the stone is more than 2 cm
• Open ureterolithotomy (necessary in rural settings where facilities and    specialists are unavailable).

In case of ureteric obstruction by stone with fever, it is urological emergency.Sepsis 6 bundles need to be completed.Urgent infusion of broad-spectrum antibiotics must be administered . Effective infection control is a priority before definitive stone removal.Ureteroscopic laser lithotripsy must be performed in these cases.

Medical Management of Ureteric Stones (4–8 mm)

Please be reminded that , the stones above 5 mm may require intervention at one point: If there is persistent pain, infection and obstruction (as delineated by ultrasound examination as hydronephrosis).

When patients present with stones of appropriate size(4-8 mm) and no significant hydronephrosis, the following medical regimen may be applied:

1. Analgesics and Anti-Inflammatory Drugs need to be given in cases where there is associated pain.

• Diclofenac sodium 50 mg orally, up to 3 times daily, no more than that dose and for no more than 3 days if there is no contraindication is present and must be given always after food if possible to protect the stomach .
• Again, to protect the stomach, co-prescribe a proton pump inhibitor (Omeprazole or Rabeprazole 20 mg once or twice daily).
• Diclofenac not only relieves pain but also reduces ureteric wall edema (inflammation) thereby increasing the chance of stone passage.
• Alternatively, rectal suppository formulations may be used (100 mg initially, then 50 mg later).
• Contraindicated in patients with renal impairment or peptic ulcer disease. In such cases, alternatives like Mefenamic acid (Meftal Spas) may be used.

2. Antibiotics

• Since infection is common with obstructing stones, urine analysis and culture should guide antibiotic choice.
• In resource-limited settings, Norfloxacin 400 mg twice daily for 5 days can be used.
• Where facilities exist, antibiotics should always be tailored according to urine culture and sensitivity results.

3. Alpha-blockers (Medical Expulsive Therapy)

• These reduce ureteric smooth muscle spasm and facilitate stone passage.
• Tamsulosin 0.4 mg once daily or Doxazosin (Duracard) 1 mg once daily may be prescribed.
• Should be avoided in patients with hypotension. Patients should be warned of possible dizziness and postural symptoms.

If the stone does not pass out even at the end of 2 months, it is highly unlikely that it will pass out.Some form of intervention, ESWL or Ureteroscopic laser lithotripsy must be done.

Sources

1. Standring S, Borley NR, Collins P, Crossman AR, Gatzoulis MA, Healy JC, et al. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. London: Elsevier; 2016. (For ureter anatomy and natural constrictions).
2. Jendeberg J, Geijer H, Alshamari M, Cierzniak B, Lidén M. Size matters: The width and location of a ureteral stone accurately predict the chance of spontaneous passage. Eur Radiol. 2017;27(11):4775–85. doi:10.1007/s00330-017-4888-1.
3. Park S, Pearle MS, Choe HS, Chung BH, Lee JY. Development of prediction models of spontaneous ureteral stone passage: a systematic review and meta-analysis. PLoS One. 2021;16(11):e0260517. doi:10.1371/journal. pone. 0260517.
4. Wang J, Chen Y, Liu M, Zhang Y, Ye H, He H, et al. Applying urinary ultrasound to predict the risk of spontaneous passage of ureteral stones. BMC Urol. 2024;24:108. doi:10.1186/s12894-024-01558-w.
5. Coll DM, Varanelli MJ, Smith RC. Relationship of spontaneous passage of ureteral calculi to stone size and location as revealed by unenhanced helical CT. AJR Am J Roentgenol. 2002;178(1):101–3. doi:10.2214/ajr.178.1.1780101.
6. Foxman B. Anatomy and physiology of the urinary tract: Relation to host defenses. Infect Dis Clin North Am. 2003;17(2):215–41. doi:10.1016/S0891-5520(03)00005-9. (For natural ureteric constrictions).
7. Assimos D, Krambeck A, Miller NL, et al.
8. AUA Guideline: Management of Ureteral Stones. Urology; American Urological Association.
9. Campschroer T, Zhu Y, Lytvyn L, et al. Alpha-blockers as medical expulsive therapy for ureteral stones. Cochrane Database of Systematic Reviews. 2018;2018(4):CD008509.
10. Sokouti M, et al. A Systematic Review and Meta-analysis on the Outcomes of URS Lithotripsy Versus ESWL for Ureteral Stones. (2023)

Author Information

Professor Dr. Toe Lwin

FRCS, FACS, Dr. Med. Sc