Yes, most kidney stones can be removed without surgery. Stones smaller than 5 mm pass on their own about 76% of the time, and even stones up to 7 mm have a 60% chance of passing without any procedure. The approach depends mainly on the stone’s size, location, and composition, with options ranging from simply waiting it out with pain management to medications that speed passage or dissolve certain stones entirely.
Why Stone Size Determines Your Options
Your ureter, the tube connecting each kidney to your bladder, averages about 3.4 mm in diameter. That’s roughly the width of a phone charging cable. Any stone wider than that has to stretch the ureter to pass, which is what causes the intense, wave-like pain known as renal colic. The larger the stone relative to the ureter, the lower the odds it will travel through on its own.
The spontaneous passage rates break down clearly by size:
- 1 mm: 87% pass without intervention
- 2 to 4 mm: 76% pass without intervention
- 5 to 7 mm: 60% pass without intervention
- 7 to 9 mm: 48% pass without intervention
- Larger than 9 mm: 25% pass without intervention
The American Urological Association recommends observation for ureteral stones up to 10 mm, as long as there are no complications like infection or kidney damage. The European Association of Urology doesn’t set a strict cutoff but notes that the chance of spontaneous passage drops steadily as stone size increases.
How Long It Takes to Pass a Stone
Smaller stones move faster. A study tracking 75 patients found that stones 2 mm or smaller passed in an average of 8.2 days, with fewer than 5% of those patients eventually needing a procedure. Stones between 2 and 4 mm took an average of 12.2 days, and about 17% of those patients required intervention. Stones 4 mm and larger averaged 22.1 days, and half of those patients ultimately needed some form of treatment to clear the stone.
These are averages. Some people pass a stone in two days; others wait six weeks. Where the stone sits matters too. Stones already near the bladder tend to pass faster than stones lodged high in the ureter near the kidney.
Medications That Help Stones Pass Faster
Doctors often prescribe a type of medication called an alpha-blocker to relax the smooth muscle in the ureter, giving the stone more room to move. In one controlled trial of 104 patients with stones in the lower ureter, 90% of those taking an alpha-blocker passed their stone compared to 71% in the group that only drank extra fluids and took pain relievers. The medication group also passed stones faster (about 10 days versus 14 days) and needed roughly 40% less pain medication during the process.
This approach, called medical expulsive therapy, works best for stones in the lower third of the ureter and is typically used for stones between 5 and 10 mm. For very small stones that are already likely to pass quickly, the added benefit is modest.
Dissolving Stones With Oral Medication
One type of kidney stone can actually be dissolved without any procedure at all: uric acid stones. These form when urine is persistently too acidic, and they account for roughly 5 to 10% of all kidney stones. Because uric acid is highly soluble in alkaline conditions, raising your urine pH with oral potassium citrate can dissolve existing stones over weeks to months.
In clinical studies, alkalinizing the urine from a pH of about 5.5 to above 6.5 resulted in effective dissolution of non-obstructing uric acid stones. The treatment is well tolerated and can eliminate stones completely, no procedure needed. Your doctor monitors urine pH periodically to make sure it stays in the target range without going too high, which could encourage a different type of stone to form. This only works for uric acid stones, so knowing your stone composition (through imaging or a prior stone analysis) is important.
Shock Wave Lithotripsy: No Incision Required
When a stone is too large to pass on its own but doesn’t necessarily need traditional surgery, shock wave lithotripsy is often the first option. The procedure uses high-energy sound waves focused through the skin to break a kidney stone into small fragments that can then pass naturally through the urinary tract.
You lie on a table while a machine sends thousands of targeted shock waves through water and into your body at the stone’s location. There are no incisions. The procedure typically takes 45 minutes to an hour, and most people go home the same day. It works best for stones in the kidney or the upper portion of the ureter, and for stones that aren’t extremely large or dense. Very hard stones (like those made of calcium oxalate monohydrate or cystine) may not fragment as well.
After the procedure, you’ll pass the fragments over the following days to weeks, which can cause some discomfort but is generally much milder than passing the original intact stone.
Managing Pain While You Wait
The pain from a passing kidney stone can be severe, and managing it well is a key part of any non-surgical approach. Anti-inflammatory pain relievers outperform opioid-based painkillers for kidney stone pain. A systematic review of multiple trials found that patients treated with anti-inflammatories had greater reductions in pain scores and were 25% less likely to need additional rescue medication compared to those given opioids. Anti-inflammatories also reduce the swelling in the ureter wall itself, which helps the stone move.
Over-the-counter options like ibuprofen or naproxen can be effective for milder episodes. For more intense pain, your doctor may prescribe a stronger anti-inflammatory. Opioids are sometimes used as a backup when anti-inflammatories aren’t enough or can’t be taken safely, but they don’t address the underlying inflammation and come with more side effects like nausea.
How Hydration Helps
Drinking enough fluid to produce at least 2.5 liters of urine per day is a cornerstone recommendation from both the American and European urological associations. For most people, that means drinking about 2.5 to 3 liters of fluid daily. The logic is straightforward: more urine flow means more force pushing the stone along the ureter, and more dilute urine means existing crystals are less likely to grow.
The evidence for prevention is strong. People who drink more than 2.5 liters per day have about a 29% lower risk of forming stones compared to those drinking less than 1.3 liters. In one long-term study, patients who maintained urine output of 2.6 liters per day had significantly fewer recurrences over five years than those producing only 1 liter daily. Water is the best choice, though low-calorie citrus juices can help by increasing urinary citrate, a natural inhibitor of stone formation.
When a Stone Can’t Wait
Not every stone is safe to manage conservatively. Certain situations require urgent intervention regardless of stone size. A stone paired with a urinary tract infection is a urological emergency because bacteria can build up behind the blockage and lead to sepsis. Fever with kidney stone symptoms warrants immediate medical attention.
Other situations that typically move you past the “wait and see” window include a stone blocking your only functioning kidney, signs of declining kidney function, pain that can’t be controlled with medication, or a stone that simply hasn’t budged after several weeks of conservative management. In these cases, procedures like ureteroscopy (where a thin scope is passed up through the bladder to retrieve or laser the stone) become necessary, though even these are minimally invasive compared to traditional open surgery, which is now extremely rare.