Abstract
Savin et al. challenges urological dogma that bladder stones represent an absolute indication for cavitating surgical treatment of benign prostatic obstruction (BPO). 1 This data would even suggest that there could be a significant number of men in whom surgery is being performed unnecessarily.
It is accepted wisdom that urinary stasis from BPO is the causative mechanism of bladder stone formation. However, despite association of BPO and bladder calculi, these stones develop in only 3%–8% of men with BPO. 2,3 It is also known that not all men who have bladder stones will have urodynamic evidence of BPO. In a study where urodynamics 4 were performed on in a similar cohort of men, 18% were found to have a normal study, 10% an underactive bladder, and only 51% confirmed to have bladder outlet obstruction (BOO). It must not be interpreted that urodynamics should be an essential investigation, but it is evidence that we should rethink our strategy for men presenting with bladder stones.
The role of underlying metabolic abnormalities in the formation of bladder stones is another consideration. In a comparative prospective analysis of men who elected surgery for BOO with or without bladder calculi, it was found that in patients in bladder calculi, 36.7% of patients had a reported history of renal stone disease. 5 This was compared with only 7.4% of patients with BOO who did not have bladder calculi. Furthermore, patients with bladder calculi had significantly higher urinary uric acid and supersaturation as well as lower urinary pH and urinary magnesium.
It is therefore reasonable to conclude that the development of bladder stones is likely caused by multiple factors, including metabolic irregularities and urinary stasis due to mechanical obstruction from BOO. This may offer an explanation as to why a concomitant outlet procedure was unnecessary in a significant proportion of patients in Savin et al.’s thought-provoking study.
If men with bladder stones were to present with urinary symptoms which on their merits warranted treatment for BPO, then clearly concomitant treatment of both the stone(s) and BPO would be the way forward. In terms of choice of BPO surgical treatment, for most men there should be no reason why options such as minimally invasive surgical treatments should not be considered, particularly for men with significant medical comorbidity or where anejaculation is of material concern. We all know from our clinical practices that some men present with relative mild symptoms or hematuria or as an incidental finding on imaging for unrelated symptoms. It would seem reasonable to treat the bladder stone initially and to then manage any ongoing or residual urinary symptoms on their merits.
Moving forward, additional prospective studies or even the establishment of a data registry would be beneficial to allow us to understand the complex relationships between bladder stones, underlying metabolic abnormalities and BPO.