RIRS (retrograde endourological procedure) for kidney stones

This is done by using various camera / scopes and done under anesthesia, either general anesthesia (GA) or spinal anesthesia.

The flexible endourology scopes

The flexible ureterorenoscopes

The procedure

Once you are under anesthesia, your doctor will insert a cystoscope to visualize the bladder and proceed to insert a guidewire, followed by a dye study to visualize the upper urinary tract. X-rays are done and the dye is injected into the urinary passage to assist the doctor while going up the urinary tract. He will then pass a small telescope with a camera (ureteroscope), through the urethra and bladder and into the ureter up to the kidney to the point where the stone is located.

Once the stone is seen, an instrument is used to break the stone and remove it. A ureteric stent will be inserted to allow easy urine passage from the kidneys as this procedure and the stone may cause swelling and bruising of the ureter.

If the stone is small, it may be snared with a basket device and removed whole from the ureter.

If the stone is large and/or if the diameter of the ureter is narrow, the stone will need to be fragmented, which is usually accomplished with a lithotripter or laser. Once the stone is broken into tiny pieces, these pieces are usually removed from the ureter. In most cases, to ensure that the kidney drains urine well after surgery, a ureteral stent is left in place.

Occasionally, a kidney stone will fragment with a laser into very small pieces (grains of sand), too small to be removed by the basket. The urologist will usually leave a stent and allow these pieces to clear by themselves over time.

Lastly, if the ureter is too small to advance the ureteroscope, the urologist will usually leave a stent, allowing the ureter to “dilate” around the stent, and reschedule the procedure 2-3 weeks later when the ureter is larger in diameter.

It is important to understand that the upper urinary tract may be narrow especially in patients who have never had stones before. In these cases, when the stone is high up the urinary tract, the camera / scope may not reach the stone during the attempt due to tightness of the ureter. The doctor will explain this to you, and when this occurs, a ureteric stent will be inserted to bypass this stone so as to allow the urine passage to be unblocked. After a few weeks, the ureter will become larger and will allow for the camera / scope to be inserted to the upper tract to remove the stone.

The retrograde endourology procedures done under anesthesia

There are various instruments that may be used to remove / extract the stones out of the urinary tract

The various accessories used for stone extraction, the stone baskets

Ureteric stents

Ureteric stents are about 24-26 cm and are inserted into the ureter. Your doctor will explain to you about the procedure.

Image of a Ureteric Stent

Ureteric stent (blue) inserted into the ureter to facilitate unimpeded flow of urine through the ureter

The purpose of inserting a ureteric stent is to facilitate the passage of urine along the ureter, as well as relieving any post-operative obstruction.

Stent-related symptoms may affect over 80% of patients, most of them are mild and tolerable. They include irritative voiding symptoms including urinary frequency, urgency (rushing to the toilet to pass urine), dysuria (discomfort on passing urine), incomplete emptying the bladder; flank and suprapubic (bladder) pain especially when straining to pass urine or while clearing your bowels; rarely incontinence (leaking of urine), and hematuria (blood in the urine). There is nothing to worry about. Although you might have these symptoms, it will not damage your kidney or bladder.

NOTE: It is critical that patients who have stents inserted must return to have their ureteral stent removed as instructed by their surgeon as a prolonged indwelling ureteral stent can result in encrustation by stone debris, infection, and obstruction and potential loss of the kidney.

Risks and Complications

As with any major surgery, complications, although uncommon, may occur with RIRS. Potential risks and complications with this operation include:

Hematuria and infection: Bleeding and infection are certainly possible following ureteroscopy (5%), but most of these are self-limiting and resolve with hydration and antibiotics, respectively. There are times when infections can be quite serious requiring prolonged stay, but mostly well controlled with I.V. antibiotics.
Stone fragments: Residual stones within the kidney or ureter may be present up to 0-20% of the time following ureteroscopy, but this all depends on the original stone size and location. These stone fragments will be seen and addressed on follow-up imaging. Ask your doctor to give you some idea of success rates for your particular stone size and location.
Ureteral injury: Injury to the ureter is the most common intra-operative complication during ureteroscopy. The reported risk of perforation ranges greatly, depending on whether it is defined as a complete perforation (0.1-0.7% – this as a hole through the entire ureter), a partial perforation (1.6% — a hole nearly through the entire ureter), or mucosal tear/scrape (5% — these are similar to a sore on the inside of the mouth). Almost 100% of these will heal with stenting (anywhere between 2 – 4 weeks). Should a large perforation occur, your urologist may choose to stop the procedure and return on another day when the ureter has had time to heal. Should your urologist not be able to place a stent after a perforation, a tube called a “nephrostomy tube” will be placed through the skin of your back into the kidney. This tube temporarily diverts the urine away from the hole and out into a bag until healing can occur and the hole closes.
Ureteral stricture and avulsion: Ureteral strictures (scar tissue within the ureter) and ureteral avulsion (complete dissociation of the ureter from the kidney) are the most feared complication of ureteroscopy. Fortunately, due to the advent of small ureteroscopes and heightened surgeon awareness, the risk of avulsion (0.05%, 1/2000) or stricture (0.2%, 1/500) is rare.
Stent symptoms: About 50% of patients who undergo ureteroscopy and have a stent will have “stent symptoms,” and this is by far the most common risk /complaint following ureteroscopy. A stent is a soft plastic (polyurethane) tube (about half the size of IV tubing) that allows the kidney to drain to the bladder regardless of swelling or obstruction. Not only can the stent “rub” on the inside of the bladder, causing a feeling of needing to urinate/overactive bladder, but also the stent allows urine to pass up from the bladder to the kidney during urination – causing symptoms from a warm, tingling sensation to intense pain in the affected flank. Ask your doctor about the risks /benefits of a ureteral stent following surgery.

What to Expect after RIRS and ureteric stenting

Immediate post-operative period: After the procedure you will be taken to the recovery room. A urinary catheter (into the bladder) will be placed after the procedure which will be removed later. Expect blood in the urine with almost every urination. With time and hydration, the urine should slowly turn from a watermelon red color to pink to clear. You may have stent pain or bladder spasms (see complications of ureteroscopy above) that can be helped by overactive bladder medications or by an indwelling bladder catheter.
Postoperative Pain: Most patients after ureteroscopy experience mild pain in the flank and/or bladder area. This is generally well controlled by use of oral narcotics (pain medication)
Ureteral Stent: Almost always after ureteroscopy, a small tube called a ureteral stent will be placed. The stent serves to facilitate drainage of urine down to the bladder. At a later date, the stent will be removed in the office by your surgeon. You may experience bladder spasms related to the ureteral stent that was placed at the end of your procedure.
Nausea: Nausea is fairly common following any surgery especially related to general anesthesia. This is usually transient and is self-limiting. Should you have excessive nausea and vomiting, you should contact your doctor for advice.
Activity: Patients may begin driving once they are off all narcotic pain medication. Most patients are able to perform normal, daily activities within few days after ureteroscopy. However, many patients describe more fatigue and discomfort with a ureteral stent in the bladder. This may limit the amount of activities that you can perform.
Diet: Most patients can start eating after a trial of clear liquids and when they do not have any nausea.
Follow-up Appointment: Patients should make a follow-up appointment with their doctor. Remember the ureteric stent is only temporary and must be removed with few weeks as instructed by your doctor.

What are the advantages of RIRS compared to other stone treatments?

Provided that the kidney stones are an appropriate size and location, an advantage of flexible RIRS is that it allows entry into all parts of the kidney. As long as the ureter is large enough to allow the RIRS to pass, there is a good chance that the stone can be broken and removed with one surgery.
Compared to ESWL therapy, a kidney or ureteral stone can be seen under direct vision by the RIRS, allowing lithotripsy with lasers followed by basketting and removal. With shock wave lithotripsy, patients are asked to pass stone fragments themselves, causing potential additional pain or obstruction. Additionally, shock wave lithotripsy may not break up very dense, hard stones (termed ESWL resistant stones).RIRS with a contact holmium laser can break up any stone, as long as the stone itself is accessible to the RIRS. Additionally,RIRS allows the treatment of stones are invisible on plain x-ray (uric acid stones).
Compared to percutaneous procedures, the RIRS is passed through natural body orifices and involve no skin incisions. Certain patient groups who cannot be treated with ESWL or PCNL (such as patients on blood thinners, women who are pregnant, the morbidly obese, and airline pilots/astronauts) can be treated safely and effectively by RIRS.

Who is not a good candidate for RIRS?

Patients with large stones: Because RIRS requires active removal of all or most stone fragments, the treatment of very large stones (>2 cm) may yield so many fragments that complete removal becomes impractical or impossible.
Patients with a history of urinary tract reconstruction: The anatomy of patients who have undergone ureteral or bladder reconstruction may not allow for passage of a RIRS.
Patients who are intolerant of stents: As stents are usually almost routinely following RIRS, patients with a history of stent intolerance may be more comfortable with other stone approaches.

What are the success rates of RIRS?

Depending on stone size, location, and number, success rates vary anywhere from 50% – 90%. Ask your surgeon to discuss success rates tailored to your particular stone disease.

What is a ureteric / ureteral stent?

The ureter is the natural tube that transmits urine from the kidney to the bladder. A ureteral stent is a specially designed hollow tube, made of a soft, plastic (polyurethane) material that is placed inside the lumen of the ureter. This tube facilitate urine passage until the obstruction has resolved. Stent size and lengths vary according to patient characteristics.

What is the reason for having a stent placed?

The placement of a ureteral stent allows urine to flow from the kidney to the bladder, even when the ureter is obstructed (stones, edema, external compression, tumors, clots, etc). Because of the stent, the kidney can continue to function properly while avoiding the pain that can occur when the kidney is obstructed. Additionally, ureteral stents allow the kidney to clear bacterial infections associated with obstruction.
Following ureteral or kidney surgery, the stent protects the ureter and allows the ureter to heal even when damaged. If a stent is not placed following surgery, occasionally, the ureteral lumen can heal with what is called a stricture (narrowing as a result of scar formation). Stents are thought to prevent this from occurring, as they allow for healing in the shape of a tube.
Occasionally, a stent is placed in order to allow the ureter to dilate over a period of time. This can be important when access through the ureter is needed to pass instruments or remove stones. Clinically, this is seen when the diameter of the ureter is too small to allow for passage of instruments or when a ureteral stone has narrowed the lumen of the ureter due to edema or inflammation. Inserting a stent allows the ureter to passively dilate, in the hope of making later attempts to get up the ureter successful.

What are the ureteric stent symptoms?

About 50% of patients will have some type of side-effect associated with their stent. It is not possible to predict who will have stent-associated difficulties or when the stent symptoms will resolve. Some patients have stent symptoms for just a few days, while others find their symptoms persist throughout their entire stent duration. Ureteral stent symptoms may include:
- Hematuria: Stents can cause blood to appear in the urine at various times. Usually, physical activity of one kind or other results in movement of the stent inside the body. This can give rise to blood in the urine. Pain may be felt in the back (loin), bladder area, groin, penis in men or urethra in women, and sometimes the testicles. The discomfort or pain may be more noticeable after physical activities and after passing urine.

- Bladder spasms: The stent can rub and irritate the lining of the bladder, making it necessary to pass urine more frequently during the day and at night. These symptoms can occasionally be improved by medication.

- Incontinence: Rarely, a stent may cause such bladder spasms leading to urinary leakage. This can usually be controlled with oral medications or with stent removal.

- Stent migration: Stents may move from their intended positions to other parts of the urinary tract, causing pain or incontinence. This nowadays is quite rare as the current stent material has a good memory and does not usually spontaneously straighten out and migrate.

- Infection: As stents are foreign bodies, bacteria can attach to their surface and become protected by a layer of slime known as a “biofilm.” In the absence of symptoms of urinary tract infection, these biofilm bacteria should not be treated with antibiotics. In any case, if you do have fever or are unwell, see your doctor immediately.

- Encrustation: Stents may be forgotten by patients and their care-givers. Over time, they can become coated with urinary salts and minerals and eventually become one very large calcified stone. This may lead to chronic obstruction, pain, chronic infections, or even complete atrophy (death) of that kidney. Typically, 2-3 procedures are necessary to remove these calcified stents. So it is important to note that these stents are only temporary and remember to get the stent removed promptly as scheduled and instructed by your doctor.

How does a stent interfere with daily life?

Most patients are able to perform normal, daily activities with a stent in place. However, many patients describe more fatigue and discomfort during the day, limiting the amount of activities that can perform. Additionally, as some patients have bladder spasms that require using a toilet more frequently, travel may be more tedious or difficult. Ureteral stents do not limit sexual activity, although there may be less enjoyment as a result of the side-effects described above.

What additional care is necessary when a stent is in place?

No particular cares are necessary. Drink at least 1½ to 2 liters of fluids a day is encouraged to help to dilute the urine. Discuss with your doctor if you have troublesome side-effects.

Following stent placement, when might it be necessary to call a doctor?

You should contact your doctor if the stent is causing you constant, unrelenting pain, if you have symptoms of a urinary tract infection (fever, rigors, feeling unwell and pain passing urine), or if the stent migrates out.

What alternatives are there to a ureteral stent?

It may be reasonable not to leave a ureteral stent if obstruction is likely to be transient. Your surgeon decides at the time of the procedure whether or not your circumstance warrants “stent free.” Occasionally, it may be possible to place a tube externally that drains the kidney. This tube is placed directly through the skin, through the kidney, and into the urinary space, called a ‘nephrostomy’ tube. This is placed under ultrasound or fluoroscopic X-ray guidance. As the tube remains outside the body, it is slightly more inconvenient, has higher infection rates, and can sometimes get pulled out by accident. The advantage of a nephrostomy tube is better drainage, ability to place contrast into the kidney to evaluate for obstruction or leakage, and removal that does not require a cystoscopic procedure.
Speak to your doctor if there is an uneasiness about the stent

How long will the ureteric stent stay in place?

The length of time the stent remains in your ureter is variable. Your doctor will probably request it to be removed somewhere between 1-2 weeks after your procedure. About 50% of patients feel flank fullness (usually during voiding) and urgency as a result of the stent. These symptoms often improve over time.
It is critical that you return to have your stent removed (as instructed), as a prolonged indwelling ureteral stent can result in encrustation, chronic infections, chronic kidney obstruction, and eventual loss of kidney function.

Informative inks:

https://urology.ufl.edu/patient-care/stone-disease/procedures/ureteroscopy-and-laser-lithotripsy/

– A review of various urinary stones, how stone forms, the endemic stone belt, and the various treatment for urinary stones – PCNL, ESWL therapy, Retrograde Ureterorenoscopy and RIRS, Antegrade Ureteroscopy

https://www.youtube.com/watch?v=_rfVGKd1ur4

RIRS (retrograde endourological procedure) for kidney stones