Stone | Nephroscopy & Ureteroscopy

Description of Procedure

 

Background

Ureteroscopy & Nephroscopy are minimally invasive surgeries to evaluate and treat conditions involving the upper urinary tract. These procedures utiliize the natural pipes through which urine is normally flowing- neither of these procedures generally requires any sort of cutting in the skin.

 

Understanding the normal anatomy will help in understanding these surgeries. Urine is produced by the kidneys and then drains downstream in the following sequence (the analogy of a house is used):

  • Papilla: these are the final ducts in the kidney where the urine exits the parenchyma ('meat') of the kidney and then drains into calyces. There are about 5-10 papillae in each kidneys. 
  • Calyx: the area that the papilla drain into (the 'rooms'), there are 5-10 per kidney
  • Infundibulum: the narrower pipes that drain the calyces to the renal pelvis (the 'doorway and hall' leading from the 'rooms')
  • Pelvis: the larger central collecting area for urine from all of the papilla (the 'Great Room' of the upper tracts). Capacity is about 10-15 mL (1/2 ounce) 
  • Ureter: the long tubule from the renal pelvis to the bladder - each kidney has one ureter; they are about 20-26 cm long (about 10 inches) and about 2 mm in diameter - just under 1/8 of an inch (these are the long hallway from the great room to the entry hall)
  • Bladder: the large collecting area of the lower urinary tract where the urine is stored.

 

'Scopy' means 'to look'. Therefore, 

  • Uretero•scopy is to look in the ureter. Scope is introduced from the urethra, through the bladder then up the ureter. The ureter is only about 2 mm in diameter (about the same size as the lead in a pencil).
  • Nephro•scopy is to look in the collecting system of kidney (upstream of the ureter).

 

Endoscopy of the urinary system has several variants. It is not uncommon to use a couple of different instruments and sometimes multiple approaches.

  1. Retrograde or antegrade: the scopes can be placed from the 
    1. Bottom up - in the reverse direction to the normal flow of urine = RETROGRADE. There is no cutting required. This is the most common approach by far - used for the majority of stones in the ureter.
    2. Top down - in the normal direction of urine flow = ANTEGRADE. This requires going through the parenchyma of the kidney - and hence a small cut is necessary to introduce the scope through the skin. The most common type of procedure using this approach is called a Percutaneous NephroLithotomy (PNL) for stone. This is also rarely used to remove tumors of the collecting system.
  2. Rigid or flexible scope.
    1. The instruments that are used for this type of surgery depend on the goals and the underlying anatomy. In general, rigid scopes are more durable, have better clarity (optics) and have larger working channels (which allows larger instruments and greater flow of irrigant). Their obvious disadvantage is that they are rigid - that is, they don't really bend. If the ureter is too curvy or if the surgery is being done from anywhere upstream of the ureter (that is, the renal pelvis and calyces) and the approach is retrograde then a flexible scope is required.

 

While there are obviously lots of different variations of these surgeries, there are a few common general approaches. 

  1. Retrograde rigid/flexible ureteroscopy for ureteral stone
  2. Retrograde intrarenal surgery (for stone)
  3. Percutaneous Nephrolithotomy

 

Ureteroscopy for Ureteral Stone

 

Ureteroscopy for ureteral stone is a procedure that is done with the intent of relieving an obstruting stone. The approach to managing stones can be found here.

 

Why

Used to relieve obstruction and the complications caused by obstructing stones. The American Urological Association and Endourological Association recommend uretroscopy as the primary treatment for stones within the mid-distal ureter and for all ureteral stones that are not visible on plain film (these are difficult or impossible to target with shock wave lithotripsy).

 

While obstruction of the kidney can be observed for short periods of time, intervention is sometimes necessary:

  1. Pain, nause, vomiting are intolerable
  2. Obstruction and infection
  3. Kidney failure
  4. Prolonged obstruction - anything over about a month is felt to put the kidney at risk for irreversible injury
  5. Low probability of stone passage despite observation

 

How

  • Ureteroscopy is usually done as an outpatient/same-day procedure in the hospital. People can usually go home 1-2 hours after completion. In some cases patients require admission for one or more day.
  • General anesthetic (completely asleep) is most common, but sometimes
  • The actual surgery usually takes about 30 minutes
  • The scope is passed to the level of the stone using video and fluoroscopy (motion X-ray) to ensure the stone is safely removed
  • Larger stones are fragmented into smaller stones to allow spontaneous passage or retrieval with a basket
  • A stent (temporary 'straw' left within the ureter and not visible externally) may be left for a few days to a few weeks. A stent may NOT be left if the following criteria are met: 
    • without suspected ureteric injury during URS, those without evidence of ureteral stricture or other anatomical impediments to stone fragment clearance, those with a normal contralateral kidney, those without renal functional impairment, and those in whom a secondary URS procedure is not planned.

Risks

Any procedure has risks associated with it. The benefits of ureteroscopy are relief of pain and preservation of kidney function. While ureteroscopy is a commonly performed procedure with each of our surgeons performing 50-100 cases each year, there are important risks to be aware ofInj.

  1. Injury to the ureter. The ureter is a delicate small tubule and may be injured during attempted removal of the stone. The ureter itself is more prone to injury when the stone has been impacted for some time, the stone is in the upper ureter, if it is large and requres more manipulation.
    1. Leakage of urine and scarring (striture) of the ureter are the most serious outcomes if an injury occurs.
    2. Fortunately, most injuries can be managed by placement of a stent for several weeks while the ureter heals. In some cases reconstructive surgery is required and very, very rarely the kidney can be lost because of irreparable injury.
  2. Failure to retrieve the stone. Ureteroscopy has the highest success rate for a single procedure for removal of stone - over 90%. However, large stones and those that are higher in the ureter may require more than one procedure. In some cases, the ureter is too small to accept the stone or the stone may be pushed back into the renal pelvis. Your urologist will determine if it is best to place a stent for 1-2 weeks and come back. The presence of a stent in the ureter will allow it to 'open up' (passively dilate) around the stent such that in most cases the second procedure will be successful because there will not be an issue with passage of the scope.
  3. Infection. Prophylactic antibiotics are often given. Some types of stones harbour bacteria which can be released with stone fragmentation.
  4. Bleeding. Minor bleeding is very common - in fact virtually everyone has some blood in the urine for a few days after the surgery and everyone with a stent has periodic bleeding until the stent is removed. Major bleeding from the ureter or from the kidney can occur but is rare.

 

What to Expect After Ureteroscopy

 

Most patients are back to normal within days - you will want to modify your schedule based on this.

  • Back pain: virtually everyone will have some pain lasting from a day or two to a couple of weeks following the procedure.
    • Repeat imaging to check for residual fragments may be necessary. Anything over 4 mm has a good chance of requiring a repeat procedure.
  • Pain an/or burning with urination: very common from passage of the scope. You will feel a need to void and often discomfort while urinating. This passes in days.
  • Blood/clot and debris in the urine. Expect this for as long as the stent is in place. It clears in a few days in most people but may last a couple of weeks in others - especially if you are on blood thinners or antiplatelet agents.

 

On the Web

UrologyHealth.org Patient Information Site on Stones

AUA Foundation Brochure on Stones

Canadian Urological Association Information on Stones

 

 

After Procedure

If you have questions that are not answered here, please contact us.

What to Expect

It is common to have pain in your side, some urinary symptoms such as urgency and frequency for 24-48 hours after a stone has been removed - it may almost feel as if the stone is still present. In most cases, symptoms usually improve rapidly and most people are back to normal in a few days.

It is normal to experience some blood in your urine, including clot and debris, for 1-2 weeks after surgery or until the stent is removed.  Bleeding may increase with activity.  If this occurs, rest and drink lots of water until the urine clears.
Even if you do not have a stent in place, you may experience some of the above symptoms.  They usually resolve within 1-2 weeks.

If you have a ureteric stent in place, you may experience the following symptoms:

  1. Urinary frequency, urgency, inability to get to a bathroom in time (urge incontinence)
  2. Mild discomfort or burning with passage of urine
  3. Pain in the kidney area (on the side of the stent), usually when passing urine.
  4. Blood in the urine, which may last until the stent is removed.

IF YOU HAVE A STENT, IT IS TEMPORARY AND MUST BE REMOVED EVENTUALLY. YOU WILL RECEIVE SPECIFIC INSTRUCTIONS ON THE TIMING OF REMOVAL. They can be left in place for several weeks if necessary and most people find they can participate in normal activities without any problems. Removal usually takes 1-2 minutes and is done on an outpatient basis without the need for any special preparation (you do not need to fast and you can drive yourself). Your urologist will tell you about how long the stent is to be in place. IF AFTER THAT TIME FRAME YOU HAVE NOT HEARD FROM THE UROLOGY OFFICE REGARDING AN APPOINTMENT TO HAVE THESTENT REMOVED, PLEASE CALL.

 

Cautions

Report any of the following to your doctor:
You cannot pass urine.
Fever over 38.5 C.
Severe pain unrelieved by medication.
Passage of large amounts of blood or clots in urine not relieved by rest and hydration.

 

Diet

Advance to usual diet as tolerated. Avoid foods which constipate you.
Certain foods may irritate your bladder, try to stay away from these: caffeine, pop, alcohol, spicy food.
Drink enough water to keep your urine reasonably clear, usually 8-10 glasses of water per day.

 

Activity

Get up and about as soon as possible after surgery.
Walk as tolerated.
You may start showering anytime.
You may have a ureteric stent in place (tube inside the passage from kidney to bladder).  Symptoms related to the stent (see “what to expect”) may be triggered by vigorous activity or even constipation.  If this is the case, please limit your activity until the stent is removed – usually within a couple of weeks.

Medications

Take antibiotics as prescribed.
Use prescription pain medication as needed.
Take a stool softener (obtain over the counter at local pharmacy) starting the night of your surgery.  Stop taking stool softeners once having soft bowel movements.  Do not take stool softeners if diarrhea occurs.
If you have not had a bowel movement by the 3rd day after your surgery, take a laxative (obtain at your local pharmacy over the counter).
You may resume taking your regular medications when you leave the hospital unless instructed otherwise.

On the Web