Ureteral Stents: Lifeline of Endourology
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 â€˜drop
of the hatâ€™. Unfortunately, there remain many problems associated with the use
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 â€˜Is a Stent really necessaryâ€™. It is true when it is said
that â€˜an Ideal Stent is not yet availableâ€™ and may be so for â€˜years to comeâ€™.
There is a podcast by Dirk Lange (Episode 28in the latest issue) of Endourology Sound bites on â€˜New Insights into Ureteral Stentsâ€™ which is worth listening and Understanding. (It has the previous sound bites as well for those interested)
On 8th August 2020, there was a Webinar Moderated by Vineet Gauhar on behalf of ITRUE on â€˜Stents: Lifeline of Endourologyâ€™. One of the participants among the Galaxy of speakers was Ben Chew and he spoke on â€˜Stents and Biomaterialsâ€™ 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.
Many speakers who spoke in the webinar have extensively quoted from the articles Provided (links).
Finally I am providing a book edited Daniel Yachia, 2nd Ed 2004 on â€˜Stenting of the Urinary Systemâ€™. (PDF attached).
(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,