Kidney stones are one of the most common and painful urinary tract conditions. They form when minerals and salts in the urine crystallise and clump together, creating hard deposits inside the kidneys. While many small stones pass naturally, larger ones may require medical or surgical intervention to avoid serious complications.
In this article, we’ll explain what size of kidney stone requires surgery, what factors influence that decision, and the types of treatments available to help patients recover safely.
Kidney stones (renal calculi) are solid masses formed when substances such as calcium, oxalate, uric acid, or cystine become too concentrated in the urine. These substances can stick together and form stones that vary in size, from tiny grains to large stones several centimetres wide.
Their size, location, and composition determine the symptoms and the type of treatment required.
• Sharp pain in the lower back, side, or abdomen
• Pain during urination
• Blood in the urine (haematuria)
• Nausea or vomiting
• Frequent urge to urinate
• Fever or chills (if infection is present)
Even small stones can be painful, but the size of the kidney stone often determines whether it can pass on its own or needs surgical removal.
Stones Less Than 4 mm
Small kidney stones (less than 4 millimetres) usually pass naturally through the urinary tract without surgery. Most people can expel such stones by:
• Drinking plenty of water
• Taking pain-relieving medication
• Using prescribed medicines (like tamsulosin) to relax the urinary tract
These stones typically pass within a few days to a few weeks.
Stones Between 4 mm and 6 mm
This size range is considered borderline. Some stones may pass naturally, while others become stuck in the ureter. In such cases, doctors may recommend medical expulsive therapy, medication to help the stone move, but surgical options are considered if symptoms persist or complications arise.
The need for surgery depends on several factors:
• Stone size greater than 6 mm: Stones above this size are unlikely to pass on their own.
• Persistent pain or urinary blockage: If the stone obstructs urine flow, pressure builds up in the kidneys.
• Infection: If a stone causes or worsens a urinary tract infection, it becomes a medical emergency.
• Kidney swelling (hydronephrosis): Prolonged obstruction can damage the kidney.
• Failure of conservative management: If the stone does not move after several weeks of observation.
In general, kidney stones larger than 6 mm often need active removal, while those over 2 cm almost always require surgical treatment.
At Solaris Hospital, Thane, patients receive expert evaluation and advanced treatment for kidney stones, from diagnostic imaging to minimally invasive surgeries like PCNL and laser lithotripsy. The hospital’s team of experienced urologists ensures safe, effective, and personalised care aimed at relieving pain and preventing recurrence.
If you’re experiencing symptoms of kidney stones, visit Solaris Hospital for a comprehensive consultation and tailored treatment plans to restore your urinary health.
The answer to what size of kidney stone requires surgery depends on several factors, but as a general rule:
• Stones under 4 mm may pass naturally.
• Stones 4–6 mm sometimes need medication or minimal intervention.
• Stones over 6 mm typically require surgery.
• Stones larger than 2 cm are best treated with advanced procedures like PCNL.
With modern minimally invasive options such as lithotripsy, ureteroscopy, and PCNL, kidney stone treatment is safer, faster, and more comfortable than ever. Consulting a qualified urologist ensures accurate diagnosis, effective treatment, and long-term prevention of recurrence.
Service Road, Ghodbunder Rd, next to AP Shah Institute of Technology, Kasarvadavali, Thane West, Maharashtra 400615
