Overview of Ureteroscopy
Ureteroscopy is a procedure that uses a special tool called an endoscope to examine and treat conditions in the upper part of the urinary tract (the system in our bodies that produces and excretes urine). Over time, improvements in technology have made this procedure more advanced and reliable. These advances include smaller, better cameras, better lighting systems, the ability to record video, and more efficient methods to break down kidney stones and remove them using “stone baskets”. Additionally, improvements in irrigation, which keeps the area clear of blood and debris during the procedure, has helped doctors see better whilst performing the procedure.
Ureteroscopy is often used to diagnose and treat conditions such as kidney stones, ureteral stones (stones in the tubes that connect the kidneys to the bladder), ureteral strictures (narrowing of the ureter), and cancers of the urothelium (the lining of the urinary tract). One critical advancement in ureteroscopy is the use of holmium lasers. These lasers can be used with different kinds of ureteroscopes, are efficient in breaking down all types of urinary stones, and can remove tumors from the lining of the urinary tract through vaporization (turning them into vapor) or ablation (destroying them).
Anatomy and Physiology of Ureteroscopy
The ureters are tubes that connect the kidneys to the bladder, helping to move urine from the kidneys to the bladder. They run downward and towards the middle of the body. The length of the ureters usually vary in adults from 22 to 30 cm, this length sometimes depends on the person’s height.
We can describe the ureters in different sections:
* Abdominal: this is the part that goes from the kidney to the blood vessels in your lower abdomen.
* Pelvic: this part goes from those blood vessels to the bladder.
Or we could divide the ureters into 3 parts:
* Upper: this goes from the kidney to the top border of a bone in the lower back, called the sacrum.
* Middle: this goes from the top to the bottom border of the sacrum, alongside the blood vessels in your lower abdomen.
* Lower: this goes from the bottom border of the sacrum to the bladder.
There are three points along the ureters that are narrower than the rest. These points are important to doctors because they are where kidney stones are most likely to get stuck. These points are:
* The junction between the kidney and the ureter (ureteropelvic junction or UPJ)
* The point where the ureter crosses over the blood vessels in the lower abdomen
* The part of the ureter that passes through the wall of the bladder (ureterovesical junction or UVJ). This part is the narrowest and sometimes doctors need to widen it before they can use larger instruments there.
The ureters are supplied with blood from many different blood vessels that run throughout your body. However, the part of the ureter that’s near the lower abdominal blood vessels doesn’t get a lot of blood supply. This can be problematic as it means that if this part is cut or injured, it might not heal very well. These vessels form a network within a layer of the ureter, so it’s generally safe for doctors to move the ureter away from surrounding tissues, provided they don’t damage that layer.
The muscle layer of the ureter helps to move urine along. It used to be thought to contain two layers running lengthways and one running in a circle, but recent research indicates that the muscles are arranged in a spiral. These muscles become thicker as you move from the kidney to the bladder. This means that holes through the entire ureter wall are more likely to occur nearer the kidney than the bladder.
The movement of the muscles doesn’t seem to need any signals from the nervous system. Instead, it’s thought to start from sites within the kidney and move along the ureter towards the bladder. Nerves transmit signals of pain from the ureter when it’s irritated, stretched, or swollen. This pain may feel like it’s coming from the side of your body, the lower abdomen, or the genital area.
One common abnormality that people can be born with is having a duplicated urinary system, which occurs in about 1 in 125 births. In this condition, there are two ureters coming out of one or both kidneys. In some people, these ureters join back together before reaching the bladder. However, in others, each ureter goes all the way to the bladder or even beyond. Girls with this condition might suffer from continuous and uncontrollable leakage of urine if a ureter ends in the vaginal area. Doctors often use various tools to navigate through and look into these duplicated ureters.
With complete duplication, the ureter that ends more towards the side and top (proximal) usually drains the lower part of the kidney and tends to allow urine to flow back into the kidney. The ureter that ends more towards the middle and bottom (distal) usually gets blocked and often drains the upper part of the kidney. This is a common rule known as the Weigert-Meyer law.
Why do People Need Ureteroscopy
Ureteroscopy is a procedure that examines or treats problems in the ureters, the tubes connecting the kidneys and bladder. There are two forms of this procedure: rigid and flexible. The rigid version is generally used for issues in the lower ureter, while the flexible ureteroscope can examine the upper ureter and inside the kidneys. This procedure can be performed through the urinary tract or via a small hole created in the kidney.
This method is beneficial for specific patients, such as those with a restructured urinary tract, kidney transplant, or certain bladder surgeries. Expert studies have shown this procedure to be quite safe with a little chance of causing any permanent harm or major complications, such as ureteral stricture, a condition that causes narrowing of the ureter.
The most common reason for ureteroscopy is to address kidney and ureter stones. If these stones fail to pass naturally or with medication, surgical intervention may be required. Other reasons include diagnosing and treating conditions like blood clots, abnormal growths, blood vessels abnormalities, or foreign bodies in the urinary tract. It can also be used to investigate the cause of unexplained blood in the urine or to diagnose urinary tract fistulas, which are abnormal connections between the urinary tract and another organ or the skin.
Additionally, ureteroscopy can be used in combination with an ultrasound conducted inside the urinary tract, to identify problems that are not visible directly, like spread of cancer into the bladder wall.
Ureteroscopy is generally favored over other treatments like extracorporeal shockwave lithotripsy (ESWL: a treatment that uses sound waves to break up stones) and percutaneous nephrolithotomy (PCNL: a treatment that removes large kidney stones through a small incision in the patient’s back), in certain cases. For instance, it’s preferred for mid or distal ureteral stones, suspected stones made of cystine or uric acid, renal stones smaller than 20mm, and removal of leftover fragments after ESWL or PCNL. It’s also the chosen treatment for patients who can’t stop taking blood thinners, or in cases where ESWL has failed or is likely to fail.
Although ureteroscopy is a bit more intrusive and carries slightly more risks than ESWL, it typically results in a greater success rate in terms of removing stones. Additionally, it does not harm the kidneys, and its impact on kidney function is usually minimal. Recent studies have indicated that early intervention, either through ureteroscopy or ESWL, should be considered for all stones larger than 7 mm, as well as those 5-7 mm located in the mid or upper ureter.
As ureteroscopy technology continues to advance, we can expect more applications and improvements to this procedure in the future.
When a Person Should Avoid Ureteroscopy
There are certain circumstances in which a doctor may advise against ureteroscopy – a medical procedure used to look inside the ureters (tubes that carry urine from the kidneys to the bladder). If a person has an active urinary tract infection, treatment and confirmation that the infection has cleared is needed before ureteroscopy. This often involves placing a small tube (percutaneous nephrostomy or a double J ureteral stent) to drain urine from the affected kidney and using antibiotics that specifically target the bacteria present.
If a person cannot have general or spinal anesthesia, this would also usually prevent a ureteroscopy. If someone has a medical condition that causes uncontrolled bleeding, or if they are taking medications to thin their blood or prevent clots, these are relative contraindications. This means ureteroscopy may still be possible, but it would have to be evaluated on an individual basis. Ureteroscopy is generally safe for people who are on blood-thinning medication.
Ureteroscopy may not be possible if a person has a ureter (the tube that carries urine from the kidney to the bladder) that is twisted or narrowed. Other roadblocks could include anatomical issues with the ureteral orifice (the opening of the ureter), prostate, trigone (triangular area at the base of the bladder), or the lower part of the ureter that could be due to cancer or other diseases. If an obstruction prevents the passing of a guide wire, an alternative approach may be tried where the wire is passed through a small tube to drain urine from the kidney down the ureter. This might work even if the usual method fails and could then allow for the placement of a stent (small tube), dilatation (making larger), and ureteroscopy to go forward.
Flexible ureteroscopy is deemed safe during pregnancy, unlike a procedure called ESWL (extracorporeal shock wave lithotripsy) that breaks up kidney stones. However, doctors need to bear in mind how anesthesia will be administered and the possibility it might trigger early labor. For pregnant women, an alternative is to use small tubes to drain urine from the kidney, but these often need to be changed every 3 to 6 weeks, which would involve additional procedures and anesthesia.
The biggest predictor of urinary tract infections after the procedure is having a urinary infection before the procedure. Other factors that may increase risk include being female, having a stent before or after the procedure, having diabetes, having positive nitrites (sign of bacteria) on urine test before the procedure, and having a longer procedure. Those with larger stones and stones located in the middle part of the ureter also tended to have more visits to the emergency room after the procedure.
Equipment used for Ureteroscopy
In today’s medicine, there are two types of ureteroscopes (medical devices to look inside the urinary tract): semi-rigid and flexible. The semi-rigid ones are great for procedures on the lower part of the urinary tube and come in sizes from 7 to 12 French (a measurement unit in medicine). They often have two channels to allow for better flow of fluids and to accommodate larger instruments like baskets and lasers. Plus, they are cheaper, more durable, have larger working channels, and are easier to move around, which can shorten operation times.
Flexible ureteroscopes come mostly in sizes from 6 to 9 French, the smallest ones being used just for diagnoses. They have advanced digital video imaging and can bend at an angle of up to 275°, compared to less than 10º with the semi-rigid scopes. These unique features help them reach inside the kidney and access the harder-to-reach lower parts.
To assist with flexible ureteroscopy, doctors use a tool called the ureteral access sheath available in sizes of 9 to 16 French. This device helps the doctors insert the ureteroscope repeatedly into the urinary tract and kidney without needing a wire or risk of injury from repeated insertions. It also helps better drain irrigation fluid, ensuring better viewing of the area and reduced internal pressures. Though there is a minor risk that the sheath could cause some physical harm, this risk is minimal if ureteral double J stents are used after the operation.
Other tools that can be inserted through the ureteroscope’s working channel include wire baskets, biopsy forceps, balloon catheters, cold knives, and electrocautery. Instruments used for breaking kidney or bladder stones (ureteroscopic lithotripsy) include ultrasound probes, pneumatic probes, and laser fibers. The ultrasound probe is less effective overall but allows continuous suction simultaneously with stone fragmentation.
Over the last 20 years, ureteroscopy has massively progressed due to the miniaturization of the scopes and accessories. The shift from fiberoptic to digital video optical systems was a significant advancement. Digital video optical systems use a camera chip attached to the ureteroscope’s tip to display a high-quality image through a single cable. This system is more durable, flexible, and thinner than fiberoptic cables, allowing for a larger working channel. Looking forward, future developments might include 3-dimensional imaging, similar to what’s used in robotic surgery.
There have also been advances in the creation of disposable flexible ureteroscopes. These tools mitigate the wear and tear on their more expensive, reusable counterparts. While their optics aren’t yet as good as reusable ones, they are ideal for emergency situations where the demand exceeds the availability. They may also be cost-effective in the long run.
Another result of these advancements is the creation of ureteroscopes with multiple channels. This allows for simultaneous viewing, tool use, and continuous irrigation. Initially developed for rigid and semi-rigid ureteroscopes, this feature is now incorporated into flexible scopes. Other optical systems, accessories, and lasers continue to evolve and become more compact.
Lasers are a versatile and effective tool for breaking down all types of stones and can also be used for tissue removal, coagulation, incisions, and vaporization. There are varied settings for lasers depending on what they are being used for. The surgeon can adjust the frequency (amount of laser pulses) and power (laser strength) depending on whether they are fragmenting stones or vaporizing them. There is, however, no common agreement on the best power and frequency settings for every function.
Different from stone fragmentation, the goal of laser vaporization or “dusting” is to break the stone into dust-like particles without direct contact. While dusting takes more time, it may limit the amount of stone material available for analysis. Sometimes, the stone might have a harder, more resistant inner core that can be managed by fragmentation and extraction rather than dusting. Often, a mix of dusting and fragmentation techniques are used.
All modern lasers work well, and the choice between them often hinges on availability and convenience rather than physician preference or specific clinical situations. Comparisons are difficult to make due to a lack of direct comparison studies, but it’s clear that progress has been made in treating urinary stone disease.
Who is needed to perform Ureteroscopy?
A ureteroscopy is a procedure that needs more than just the main doctor, known as a surgeon, to perform it. There’s also an assistant who could be a resident doctor, a scrub tech (who assists surgeons during surgery), a nurse practitioner (a nurse with additional training to provide healthcare services), or a physician assistant. These assistants help by holding special wires, giving the right tools, and helping to use various kinds of surgical baskets (tools to capture and remove small objects from the body).
When a piece of equipment called a radiological C-arm is needed to take X-ray images during surgery, a radiology technician (who specializes in using this equipment) is also needed. However, if they have a specific type of surgical table designed for this kind of surgery, a radiology technician might not be required.
It’s also important to have anesthesia staff in the operating room, who are responsible for administering medications that help you sleep and be pain-free during the surgery. They are present to monitor your body’s response while you’re under anesthesia. Furthermore, a circulating nurse is crucial to be there as they coordinate the entire procedure, making sure all the needed supplies and instruments are prepared and everyone is working together efficiently.
Preparing for Ureteroscopy
Before having a ureteroscopy, which is a procedure to look inside the ureters and kidneys, it’s crucial to do some planning to avoid problems and limit the time spent in surgery. To prepare for this procedure, your doctors will review your previous imaging tests, like CT Scans or x-rays of your kidneys, ureters, and bladder. Additionally, the doctors will conduct a urinalysis and urine cultures to make sure there’s no infection in the urinary tract.
When you’re about to have the surgery, you’ll be asked for your consent, and the doctors will thoroughly discuss the potential risks and other available options. You’ll then be given an anesthesia to keep you relaxed, and the healthcare workers will clean your body to prevent any infections.
Sometimes, things like narrowing of the ureter, excessive bleeding, or technical issues might come up while the surgery is underway. In such instances, the doctors might have to place a small tube called a ‘double J stent’ in your ureter and you’ll need a second surgery. They’ll let you know about this possibility before the first surgery, so you won’t be in for any surprises.
Usually, an antibiotic is given to prevent infection. The type of antibiotic you’ll receive will depend on your previous medical history and any additional risks you might have. It’s usually either a first or second-generation cephalosporin or a combination of other drugs.
When the doctors decide on an antibiotic, they have to make sure it’s in your system before the procedure starts. It can be either taken orally or given through an IV; but the IV is usually preferred, especially if you’re asked to fast before the procedure.
Sometimes, they might even give you an additional dose of an antibiotic called gentamicin before the surgery. This is to ensure post-operative infections are well controlled, especially if you’re at high risk of an infection.
While it’s recommended you to be fully unconscious (general anesthesia) for the surgery, sometimes a combined spinal-epidural anesthesia is used as it can work fine. However, the doctors will want you to be fully anesthetized so that there’s no unexpected movement during the surgery.
Just before the surgery starts, the nurses will arrange all the necessary tools and instruments the doctor needs. They will make sure everything’s in place for a smooth procedure.
If doctors predict that the ureters are narrow, they might place a double J stent before the surgery to make the ureteroscopy easier. Also, if the ureter is too narrow during the operation, they might need to cancel the ureteroscopy, place a double J stent, and resume the surgery on another day. This is done to ensure your safety and prevent complications.
How is Ureteroscopy performed
Ureteroscopy is a procedure that helps doctors examine a person’s urinary system. This is done using a ureteroscope, a thin viewing instrument, that helps doctors inspect the tubes that carry urine from the kidneys to the bladder known as ureters. This process starts with a preliminary examination called cystoscopy. Cystoscopy is done immediately before ureteroscopy to assist with understanding a person’s specific anatomy and visualize the bladder.
In male patients, the penis must initially be held upright. This helps to straighten the urethra and facilitates the insertion of the cystoscope. Once the cystoscope reaches the bladder, a thorough examination is conducted. Usually, a smaller ureteral catheter is flushed to remove any air bubbles and then inserted inside the ureter through the cystoscope.
Sometimes, if difficulty arises while inserting the ureteral catheter, specialized techniques and devices are used to overcome the problem. The use of angled tip guidewires and other tools can help the doctor ensure safe and efficient insertion of the cystoscope.
To examine the ureter’s anatomy and determine the presence and location of any stones, a special contrast solution is gently injected into the ureter. If there’s a suspicion of an infection, a double J stent, or special tube, is placed inside, and the procedure is postponed until after proper treatment with antibiotics.
Before inserting the ureteroscope, the bladder is emptied. This helps push the ureteroscope through the bladder without discomfort. The ureteroscope is carefully guided up to the kidneys. If a stone is causing the problem, the technique used will depend on the stone’s location, size, and other factors.
A special sheath may be inserted over the guidewire to assist with the procedure, especially if multiple or large stones are involved. However, the use of this sheath should be done carefully to avoid any injury to the ureter or kidneys.
Overall, the use of a ureteroscopic access sheath along with two guidewires is usually preferred, as it provides a safer and more efficient approach for dealing with various urinary issues.
Possible Complications of Ureteroscopy
Ureteroscopy, a procedure that examines the inside of the kidneys and ureter using medical instruments, has improved significantly over the years. New tools and techniques have been developed to ensure the procedure is as safe as possible. Even so, there are still some risks involved.
Less severe complications might include blood in the urine (hematuria), mild urinary tract infections, discomfort from a double J stent (a small tube that helps urine flow from the kidneys to the bladder), and a temporary rise in creatinine levels (which can indicate kidney function problems).
Certain uncommon but serious complications can also occur. These include severe urosepsis, which is a dangerous infection that can spread through the body; stone migration, where a kidney or bladder stone moves into an unexpected location; ureteral perforation, which is a hole in the ureter; ureteral stricture, which is a narrowing of the ureter; and ureteral avulsion, a condition where the ureter is torn or detached. However, remember that these severe complications are rare.
What Else Should I Know About Ureteroscopy?
Ureteroscopy is a remarkable tool for medical experts in urology that focuses on treating issues within the urinary system. It’s an effective, safe technique that’s used either to diagnose problems or to do small and relatively non-invasive operations, all in the outpatient setting. However, doing this procedure correctly requires thorough training and care to avoid complications. Innovative developments in medical tools will allow doctors to treat more complex cases in the future with this technique.
The benefits and drawbacks of ureteroscopy are often compared to those of ESWL (Extracorporeal Shock Wave Lithotripsy), another procedure used to remove kidney stones.
Ureteroscopy often results in immediate removal of stones and decreases the likelihood of needing a second procedure, making it a more efficient choice compared to ESWL. It is quite versatile as it can be used to reach kidney stones located in different parts of the urinary tract, which ESWL often fails to clear. Furthermore, ureteroscopy can be used to break down and remove stones formed from a variety of substances that are typically difficult to treat with ESWL.
Ureteroscopy can also be performed safely in specific cases, like during pregnancy, and in patients receiving blood thinners or those with abnormal blood clotting.
However, it’s important to note that ureteroscopy is more invasive than ESWL, needs general anesthesia, might require more time in the operation room, and has higher risks of complications. In certain situations, a tube called a ‘double J stent’ might need to be temporarily placed in the urinary tract, which can be uncomfortable and often needs another procedure to remove later.
On the other hand, ESWL is less invasive than ureteroscopy and it’s highly safe, with very few complications. This method uses minimal anesthesia and achieves almost the same results as ureteroscopy, although it may require a second treatment and longer time to fully pass out the fragments of the broken stones. The discomfort of using a ‘double J stent’ is usually not needed with ESWL.
However, ESWL is not the best choice when dealing with really hard stones, extremely large stones, and in cases where treatments were unsuccessful previously, In these situations, ureteroscopy is preferred. Additionally, ESWL cannot be performed safely in pregnant women or patients with high blood pressure, untreated abnormal blood clotting, or those taking blood thinners.
