Q. Figure 10.5 is the KUB x-ray of a 36-year-old man. He complains of intermittent left loin pain and has microscopic haematuria. How would you treat this stone initially?
Figure 10.5
A. Figure 10.5 shows a 4-5 mm radiopacity in the left kidney, likely to be a stone.
The initial management of a stone of this size would be ESWL. There is a 70% chance that stone clearance would be achieved, if it is in anatomically normal calyx.
Q. This stone has been treated with two sessions of ESWL. While it appeared to have
partially fragmented, the fragments did not clear. What are the possible reasons for this?
A. One possible reason is that this stone lies within a calyceal diverticulum. Other possibilities include that the stone is too hard to be fragmented with ESWL, and this might indicate that the stone is a calcium oxalate monohydrate stone.
Q. What is a calyceal diverticulum, and how would you manage this stone?
A. Calyceal diverticula are nonsecretory urothelial-lined compartments in communication with the renal collecting system, although the point of communication is often only very narrow. While it is reasonable to manage asymptomatic diverticular stones conservatively, those causing pain, infection or bleeding should be treated.
ESWL can been used to treat calyceal diverticular stones, but due to poor drainage of the fragments, the stone-free rates are low (often 20%-30% only), and are not comparable to that of PCNL, where stone-free rates are around 90%. Ureteroscopy can also be used, often with laser incision of the diverticular neck initially, allowing stone-free rates of up to 70%.
However, as well as clearance of the stone, obliteration of the diverticulum should be attempted. This is not possible with ESWL, and success at ureteroscopy is low. However, PCNL provides excellent access for this and obliteration rates of up to 80% are seen. Finally, laparoscopic and robotic-assisted laparoscopic approaches to calyceal diverticular stones have been reported with good success.