A Bladder Donut: an intriguing formation from a fractured encrusted stent

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For ease of reference and to aid in teaching purposes, the field of Urology has been filled with descriptions that evoke memories from childhood, nature, events, and other parallel occurrences. These include the basic anatomy to describe the outline of the ureteral orifice like “Golf Hole”, “Horseshoe,” and “Stadium” shapes,(1) also for Imaging of the Penile Implant like the Pac-Man and the ubiquitous Grover image from Sesame Street,(2) a “Drooping” Lilly sign to depict the lateral deviation of a lower pole moiety in a duplex renal system,(3) and even the classic “Balloon on string” sign, which represents a pelvic-ureteric junction obstruction where the ureter is seen to exit eccentrically from a dilated renal pelvis on an excretory urogram image.(4)

Since fragmentation and ureteral stent fracture may occur after prolonged stent duration or in cases of the forgotten stent, the possibility of circular fusion after stent fracture may result in a circular-shaped encrusted stone pattern that resembles a classic donut. This occurs since the coil memory is preserved despite being fractured off from the stent body.

Although the forgotten stent may present as an Endourology nightmare in some instances,(5) measuring the complete stent length upon stent retrieval and complete endoscopic and fluoroscopic evaluation of the entire renal tract will ensure that the whole stent and all resultant encrustations have been successfully removed.

In cases of forgotten stents with resultant encrustation, we want to draw the reader's attention to the possibility of encountering a “Bladder” Donut (Fig 12.1A). This image can be easily related to a hungry registrar who may have missed their lunch break to attend to yet another case. A corresponding fluoroscopic image is shown (Fig 12.1B).

Figure 12.1A.

 Endoscopic (Cystoscopy) image depicting the circular calcified, distal ureteric stent coil, which fused to form a circular-shaped encrustation – the “bladder” donut

Ethical approval for publishing the image was obtained from the University of Witwatersrand, Human Research Ethics Committee (Medical)

References

1. LyonRP, MarshallS, TanaghoEA. The ureteral orifice: its configuration and competency. J Urol. 1969; 102(4):504–509. doi:10.1016/s0022-5347(17)62184-0

2. PuaU. Coronal computed tomography of penile implant. Urology. 2009; 73(4):747. doi:10.1016/j.urology.2008.10.044

3. SahakyanK, SpevakMR, ZiessmanHA, GorinMA, RoweSP. The scintigraphic drooping lily sign. Clin Nucl Med. 2018; 43(5):352–353. doi:10.1097/RLU.0000000000002049

4. BushWH, BrannerGE, LewisGP. Ureteropelvic junction obstruction treatment with percutaneous endopyelotomy. Radiology. 1989; 171:535–538. https://doi.org/10.1148/radiology.171.2.2704820

5. AdamA, de JonghR, MathyeC, BhattuAS, PatelH. The first report of 3 forgotten encrusted double J stents in the same ureter: an endourology nightmare! Afr J Urol. 2017; 23(4):224–227.