Abstract: PD16-11
Sources of Funding: None.

Introduction

The choice of treatment for symptomatic calyceal diverticula (CD) depends on size, location, and degree of stone burden. Percutaneous treatment is preferred for large CD, lower pole CD, and CD with a large stone burden, but its safety for anterior CD has not been evaluated. In addition, the necessity to treat the diverticular neck and the need for metabolic evaluation remains controversial. We sought to shed some light on these issues based on our significant experience.

Methods

We identified 51 patients in our IRB approved Endourology database with stone bearing CD that were treated percutaneously by a single experienced surgeon. We separated patients into those with stones only in their CD (CD only) and those who also had renal calculi outside of their diverticulum (CD plus). Demographic data, size and location of the CD, treatment of the diverticular neck, intra-operative and post-operative outcomes, stone analysis, and 24-hr urine parameters were recorded. Urine parameters were also compared to stone formers without CD (non-CD).

Results

CD only patients are younger (44 vs. 54 y, p=0.024), have lower BMI (23.2 vs. 27, p=0.032), and are more often female (71% vs. 44%, p = 0.046) compared to non-CD patients. Anterior CD (66%) were more common than posterior, and 52% of the CD were found in the upper pole. Average CD size was 2.5cm with a stone burden of 1.47 cm. PCNL was performed safely and completely in 98% of the patients, with a complication rate of 4%. The diverticular neck was dilated in 44% of the cases. In follow-up there was 1 symptomatic recurrence managed by ureteroscopy. Calcium phosphate was contained in 82% of stones. All CD patients had at least one metabolic derangement, similar to regular stone formers, but with unusually high levels of urinary calcium and pH (Table 1).

Conclusions

Percutaneous treatment of CD is safe and effective regardless of size or location (including anterior CD). Infundibular neck dilation does not appear to be necessary. A significant proportion of CD patients have metabolic abnormalities. Stone formation is likely a result of stasis and metabolic factors, and CD patients are at risk for future renal calculi.

Funding

None.