A الدعامة المرنة (Urology catheter) is a long, thin tube, which is slightly curved and has several side holes along the tube length. This type of stent is used to help the urologist guide a catheter or other instrument into the urethra during a urological procedure. The urologist inserts the end of the catheter into the bladder, then pushes the catheter through the urethra until the end touches the base of the trachea (the first and second cervical vertebrae). When the catheter is in the correct position, the urologist can feel a tingling sensation and can see the bulge of the trachea through the transparent protective sheath on the end of the catheter. The other end of the catheter can be connected to various medical instruments such as a videolaparoscope, a cystoscope, or a ureteroscope. When the flexible stent is in place, it provides the urologist with a stable and comfortable position while performing the urological procedure.
History of flexible stents
The first flexible stent was created in the 1980s. The idea for the stent came from urologists who wanted to have a stable and comfortable position while performing catheterization. One of the first manufacturers of flexible stents was the Cook company. After Cook, other companies such as Pioltet (formerly PeeGee), Abbott, and others entered the flexible stent market. The majority of these stents are made from polyurethane or silicone.
How do urologists select a flexible stent?
Urologists must take into consideration many things when selecting the right flexible stent for their needs. First, they must consider the size of the urethra. The smaller the urethra, the more curved the stent should be to fit into the smallest opening. Larger urethras require wider, straighter stents. The second factor urologists must consider is the length of the stent. The stent should reach from the bladder to the base of the trachea. This is determined by the distance between the symphysis pubis and the thoracic outlet. The base of the trachea is where the esophagus meets the bronchi (bronchial tubes). The third factor is the number of side holes along the catheter. The more holes, the more flexibility and the less likely the stent will become kinked during insertion. The last but not the least important factor is the diameter of the holes. The smaller the holes, the more flexibility and the less likely the stent will become blocked during use. Too large of a hole and the fluid in the urethra could leak out through the hole which defeats the purpose of the stent. Additionally, if the hole is too large, it will also increase the possibility of infection. Thus, the smaller the hole, the better.
What are the materials used for making flexible stents?
Aside from being flexible, the stent material must be biocompatible and withstand repeated use in a human body without deteriorating or breaking down. The majority of the flexible stent materials are made from latex, polyurethane, or silicone. Latex is a commonly used material for this type of stent and is actually the preferred one, due to its flexibility, transparency, and biocompatibility. The only drawback to using latex is that it is highly thrombogenic (it tends to cause blood clots), so extra care must be taken during and after surgery to prevent the formation of blood clots. Additionally, some urologists prefer to use polyvinyl chloride (PVC) for their stents, as it is more stretchable than latex. Although this is a great alternative, PVC is not ideal for long-term use in the body as it slowly disintegrates (dissolves) into soft plastic pieces which can eventually lead to more serious health problems. Thus, for PVC stents, the lifespan is usually around six months to a year before they need to be replaced.
How do I insert a flexible stent?
The process of inserting a flexible stent is very similar to that of inserting a straight-ish stent. The main difference is that the urologist must take extra care to prevent the stent from bending or kinking as it goes into the urethra. If the stent gets kinked or bent during insertion, it can cause serious damage to the urethra and/or bladder. In most cases, this requires that the urologist remove the bent or kinked stent and replace it with a new one. Sometimes, if the urethra is particularly narrow, an additional doctor or nurse is required to help lift the bladder and/or to prevent the catheter from slipping out during the insertion process. In either case, the damage that can be caused from the insertion of a kinked or bent stent requires that the urologist take extra time to recover from the surgery and increase the risk of infection.
How long should I leave the flexible stent inside the urethra?
This really depends on the type of procedure the urologist is performing and the material the stent is made of. For most cases, the urologist will leave the stent inside the urethra for about 30 minutes to one hour. However, if the procedure is particularly long or complex, the stent may need to stay in place for two to four hours. In some cases, the stent may need to be removed and replaced with a longer one just to fit the whole procedure. It is always best to ask the urologist or the nurse who is assisting them during the procedure if they need help removing the stent after the procedure is over.
How do I care for a flexible stent?
Just like with any other medical device, the urologist must regularly clean and care for the flexible stent to prevent infections and other health problems. The stent can be cleaned with soap and water just like any other device, although some urologists prefer to use alcohol or Chlorhexidine (performed as a mouthwash or gargle) to clean their stent.
Additionally, the stent can be wiped down with an antibacterial hand sanitiser after every use. This is to reduce the risk of infections. Similarly, some urologists prefer to clean the stent with a chlorinated solution just before and after every use. The stent can also be dried with a clean, dry cloth to keep it dry and free of any bacteria or other microbes which could cause an infection.
Where can I buy a flexible stent?
The Cook Flexible Stent is probably the most popular and widely used flexible stent. Other companies that also produce flexible stents include Abbott, PeeGee, and others. You can find the Cook Flexible Stent (size “Small”) for around $100–$120. Other manufacturers' models may be a little bit more expensive, but they are still much cheaper than renting a nephrostomy tube for a day or paying for a surgery to implant a metallic stent. In most cases, nephrostomy tubes are used for longer than 30 minute procedures and usually cost around $400–$500, plus the cost of renting the machine.
Is it safe to use a flexible stent during a cystoscopy?
Using a flexible stent during a cystoscopy is usually safe. The main issue is that with a cystoscope, the light inside is very bright and can cause eye damage if used for a long time. So, the urologist must be careful not to look at the cystoscope screen for too long during the procedure. Additionally, some urologists prefer to use special lighting during cystoscopies which helps reduce eye damage. However, this also increases the time it takes to perform the procedure.
Can I use a flexible stent during a urethroscopy?
Using a flexible stent during a urethroscopy is also usually safe. The main issue is that, like with a cystoscope, the light inside a urethroscope is very bright and can cause damage to the eyes if used for a long time. This is why most urologists prefer to use a cystoscope during these procedures. Some urologists also use a small magnifying lens between the eye and the eyepiece to reduce this risk of damage. Like with a cystoscope, the time it takes to perform the procedure is also increased due to the extra steps required to clean and change the lens between each use. Additionally, some urologists prefer to use a specialized lubricant, which is applied to the end of the scope, to make the procedure easier and more comfortable.