Surgery with the urologist is sometimes needed for the following indications: 

• stone is stuck and does not pass after observation of a few days to weeks
• stone is so large that it is unlikely to pass on its own
• stone with fever
• stone with heavy bleeding in the urine

Urologists are the surgeons who perform stone removal surgery. There are three types of surgery:

• ureteroscopy with laser lithotripsy 
• extracorporeal shock wave lithotripsy (ESWL)
• percutaneous nephrolithotomy (PCNL)

The decision about whether to extract the stone by surgery, when to do surgery, and what type of surgery should be done is best discussed with a urologist. 

For information on Urology at Stanford, please see this link: Stanford Urology

Removal of the stone is only one part of kidney stone care. The other part is to determine why the stone formed in the first place. This information can provide concrete steps for patients to modify their diet (and possibly start a new medication) so that the next stone can be prevented.

Stone prevention is guided by three pieces of information:

• stone analysis
• review of the diet
• 24-hour urine testing

Since kidney stones are made up of minerals in the urine, the logical approach for stone prevention is to consider the following relationships:

• mineral composition of the stone and excretion of minerals in a 24-hour urine sample
• mineral composition of a 24-hour urine sample and dietary habit

One of the functions of the kidney is to excrete minerals so that the level of minerals in the body are in steady state balance. We look at the chemical composition of the kidney stone and link this information with the concentration and amount of minerals in a 24-hour urine sample from a patient. We then ask the patient what he or she ate that day of the 24-hour urine collection. By correlating the dietary log with a 24-hour urine sample, we can advise patients on how to modify their diet to improve the urine profile and reduce stone risk. Since there is variation in diet and collection of a 24-hour urine sample, we usually ask our patients to consume their typical diet and collect two baseline 24-hour urine collections.

There is indeed a heritable component to a kidney stone disease: patients with a family history of kidney stones are almost three times more likely to develop a stone compared with those without a family history. Metabolic predisposition to stone disease, which can be uncovered by blood or 24-hour urine testing, is also heritable. 

However, the fact that kidney stone disease can be heritable does not necessarily mean that all patients should undergo genetic testing. Most patients with a family history of kidney stone disease still likely have numerous genes with small effects that conrtibute to stone risk. We acknowledge that in select cases, particularly when stone disease is severe or accompanied by kidney disease, it will be valuable to test for a genetic cause for stone disease. 

Many diet regimens aim to help patents lose weight. While these diets restrict consumption of specific nutrients, they typically counterbalance this restriction with an increase in other nutrients or food groups, some of which may increase stone risk. For example, the Atkins diet imposes severe restriction on carbohydrate intake, which is replaced by an increase in protein or fat consumption. In the short term, consumption of an Atkins diet can increase urine calcium excretion and decrease urine pH and urine citrate excretion. This can increase risk for either calcium oxalate or uric acid stones.

A similar mechanism operates for patients who ingest a ketogenic “keto” diet, which typically consists of 5% carbohydrate, 15% protein, and 80% fat. Patients who consume a ketogenic diet often develop acidic urine, hypocitraturia, and hypercalciuria. Ketogenic diets have been linked to recurrence of uric acid stones, calcium stones, or a mixture of both patients uric acid and calcium stones.

The Paleolithic diet replicates the diet of hunter-gatherer from prehistory, a time in which processed food (cereals and dairy products) was absent and unprocessed food (meat, eggs, nuts, fruits, and vegetables) predominated. The higher intake of fruits and vegetables should increase delivery of alkali to the body, leading to an increase in urine citrate and a decrease in urine calcium. However, it is also possible that higher intake of fruits and vegetables would increase urine oxalate excretion. We thus do not know for certain what is the net effect of the Paleolithic diet on stone prevention. The same is true for the Mediterranean diet: there may be offsetting effects of Mediterranean diet on stone prevention. On the one hand,  the Mediterranean diet will lower sodium intake and raise fruit and vegetable intake, which will lower urine calcium and increase urine citrate and pH. On the other hand, the Mediterranean diet contains a rich supply of nuts, which have high oxalate content.

Alkaline water has been advertised to be healthy because the pH is higher, typically around 9.0. This advertising claim begs the question of whether alkaline water can be used for kidney stone prevention. We believe that the answer depends on what is in the alkaline water. Without knowing the specific contents inside different formulations of alkaline water, we cannot recommend it over regular water for stone prevention.

Why? The reason is that water is a not a buffered solution, so it takes very little acid or alkali to change the pH of water. For example, in distilled water, it takes < 1 mEq of alkali to change the pH from 7 to 9. As a comparison, one-half teaspoon of baking soda contains approximately 25 mEq of alkali.  There is not enough alkali in plain water to deliver alkali in a clinically meaningful way. It is possible that alkaline water formulations may contain alkali but the ingredient labels usually do not give quantitative information about the amount of alkali.

The physiological basis for consuming citrus-based beverages is that they provide a source of alkali, which will increase urine pH and urine citrate. In theory this urine profile can lower risk of uric acid or calcium stones. However, whether a given citrus-based beverage contains alkali depends on the proportion of protons (H+) and citrate. If the proportion is 1:1, the citrus-based beverage contains citric acid, and citric acid will not provide alkali to the body. As a result, there will be no effect on either urine pH or urine citrate.

Over-the-counter beverages can provide an alternative source of alkali that may be more palatable and cost less than prescribed medications. We believe that these beverages should not be used be used as a general recommendation for stone prevention but rather as a specific recommendation-- to be initiated in response to either a low urine pH or hypocitraturia. Moreover, these beverages should be dosed to normalize urine pH or level of urine citrate excretion with the aim to lower stone recurrence. For appropriate dosing of a citrus-based drink, we must know the exact proportion of citric acid (which is not a base equivalent) to citrate (a base equivalent) for that drink.

Knowledge of the proportion of citric acid to citrate for each drink will dictate the volume needed to deliver sufficient alkali to the body; for lemon water or juice, this volume may require ingestion of two quarts a day to raise urine citrate to an effective range. Other citrus drinks, such as orange and grapefruit juice, may represent a good source of citrate but come with high sugar content and may cause heartburn when ingested in high volumes. We have recommended lower calorie options such as Diet 7-Up, Diet Sunkist Orange, or Crystal Light Lemonade.  A newer formulation of alkali is Moonstone, which contains 30 mEq per serving, can be served as a dissolved packet, gummy, or capsule.