Ureteral Stents: Lifeline of Endourology

• 04 Sep 2020 05:14:26 PM
• |Endo Urology

Dear All,

The use of ureteric stents is increasing and the list of indications for their use has expanded from temporary or permanent relief of ureteric obstruction to include temporary urinary diversion following surgical procedures on the urinary tract and stents are being used at a ‘drop of the hat’. Unfortunately, there remain many problems associated with the use of stents.

The increasing tendency to insert a stent at an earlier opportunity than before, on the basis that it will reduce morbidity of, for example, ureteric obstruction, is occurring at the cost of considerable discomfort to patients. The sequelae of stent insertion are under-reported and the incidence of stent removal or replacement is high.

Perhaps more worrying is the suggestion from clinical studies that stenting does not reliably relieve obstruction, commonly the very reason for stent insertion in the first place. This finding may be influenced by type of stent used, the material from which the stent is made, and the reason for the ureteric obstruction in the first place.

What properties would an ideal stent have to possess? The pathophysiological properties relate to the effect of the stent on ureteric mucosa and ureteric function and the effect of urine on the stent. These effects reflect the biocompatibility of the stent. Many physical properties of the stent material will affect both performance and comfort of the patient; these include tensile strength, compliance, flexibility and elasticity, and surface characteristics such as wettability and smoothness. The ideal stent material should possess the ability to resist fouling with formation of Biofilm and Encrustation.

For the patient, the stent should be inert and its presence should not be noticeable. The surgeon requires a stent that has a smooth profile for easy insertion and removal, a wettable surface on demand (for ease of insertion past obstructing stones, for example), good flexibility, and good ease of passage over a guide wire. For the purchaser, even the highest-quality product should still be affordable.

Of late several new stent materials have evolved having most of the qualities needed for a stent. But still this is an evolving area with many limitations to overcome. Despite the advances in Stent Design and Material, the morbidity associated with Ureteric Stents should make the urologists ask ‘Is a Stent really necessary’. It is true when it is said that ‘an Ideal Stent is not yet available’ and may be so for ‘years to come’.

There is a podcast by Dirk Lange (Episode 28in the latest issue) of Endourology Sound bites on ‘New Insights into Ureteral Stents’ which is worth listening and Understanding. (It has the previous sound bites as well for those interested)

https://home.liebertpub.com/lpages/richard-wolf-learning-center/222

On 8th August 2020, there was a Webinar Moderated by Vineet Gauhar on behalf of ITRUE on ‘Stents: Lifeline of Endourology’. One of the participants among the Galaxy of speakers was Ben Chew and he spoke on ‘Stents and Biomaterials’ which is worth listening to apart from other talks. I am providing the Link from which you can listen to this excellent Webinar if you did not have an opportunity earlier.

https://youtu.be/UUoDLqOjgqE or

https://www.youtube.com/watch?v=UUoDLqOjgqE&feature=youtu.be

Many speakers who spoke in the webinar have extensively quoted from the articles Provided (links).

https://journals.sagepub.com/doi/pdf/10.1177/2051415817722934

https://onlinelibrary.wiley.com/doi/pdf/10.1111/iju.14119

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5893657/pdf/11934_2018_Article_779.pdf

https://www.liebertpub.com/doi/pdf/10.1089/end.2016.0709

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7403435/pdf/rru-12-303.pdf

https://bmcurol.biomedcentral.com/track/pdf/10.1186/s12894-020-0577-y

https://www.karger.com/Article/Pdf/447201

Finally I am providing a book edited Daniel Yachia, 2^nd Ed 2004 on ‘Stenting of the Urinary System’. (PDF attached).

https://www.dropbox.com/s/s9s7acmwb3kad6h/Stenting%20the%20Urinary%20System%2C%20Second%20Edition.pdf?dl=0

(If the Link does not open, for those interested I can provide the book)

It is with great pleasure I am providing these materials for knowledge need be disseminated and not kept to oneself.

With warm Regards,

Venu

Comments(2)

• 

  Dr. Roy Chally

  05 Sep 2020 02:25:17 PM

  Professor Venugopal has posted a number of good articles on stents. It will be useful to go through them. In one article it is mentioned that stents affects affects the quality of life in 80%. Another article mentions that stents are obstructive when the is no PCS dilatation. There is a clear need to question the role of stent in every patient we put a stent. 

    It will be worth while for each department to keep an audit of every patient with stent and to review whether the stent was really needed / helpful. I strongly feel that we are over using it for the surgeons comfort rather than the need for it, in the patient.

    Now I see many with stent intolerance. More with stents made in India. Is this due the impurity’s in the stent?

     Stent audit will tell us whether the stent was really helpful. Many resort to stenting as PCN is technically more challenging. Ureteric stents will never be a substitute where PCN is clearly indicated. 

   Hope all are keeping a stent register. 

  Roy Chally

• 

  Ravindra Sabnis

  06 Sep 2020 01:40:25 PM

  Respected venu sir has put in lot of articles. 

  Ben Chew is one of the international authority on stents, who has done lot of research on stents. He presents his work very regularly in WCE, SIU...etc Dr Ravi Kulkarni has also done lot of work on stents. Written a book on stent, I have also contributed a chapter in that. 

  Stent is life line of endourology - is very true. We can't imagine enodourology without stent. However whenever any particular modality, operation, becomes promising, its overuse starts & then we really come to know the problems of it. Same thing happened to it to ESWL in past. 

  Today as Dr Roy Chally sir has aptly mentioned, we are seeing over use of stents. Several places where stent is put for no reason. We do not pay attention to stnt symptoms & fantastic surgery is spoiled by stent symptoms. 

  I have seen in many conferences, wehn we discussed why stent was put - answer given by senior & reputed urologists is "you can sleep peacefully at at night" . That can't be explanation in scientific meeting. But that much is the over use of stent. 

  Sir has rightly pointed out that, Sometimes stent can obstruct system.we have seen this many times, when tight ureter, you put stent & pts come with hydronephrosis  as urine mainly drains by the side of stent. Often this used to happen with endopyelotomy stent which was 12 F at one end. We have seen better results with 2 stents instead of 1 stent in such situaiton. 

  Biological, degradable stent research is intense. Dream is like vicryl or catgut, in certain days, stent will dissolve but that dream  still far from reality. 

  Permanent stent- metal - are useful in many occasions. 

  so in nutshell, as Venu Sir tells, any thing done in excess is not good. Amrit in excess dose can become poison. Like our webinars - in excess number is counterproductive. Similarly over use of stent can bring disrepute to stent.