Historically, percutaneous treatment of stone-bearing caliceal diverticula has resulted in the best success rates when examining factors such as symptom relief and stone-free rates (Jones, et al, 1991). Many groups have reported modifications in their percutaneous approach which have reportedly improved patient outcomes, but these series have very limited populations. Another issue concerning stone-bearing caliceal diverticula centers on the etiology of stones formation within these areas. This topic remains a subject of debate, with conflicting data in the literature.

Caliceal diverticula are non-secretory cavities which are connected to the remainder of the renal collecting system through narrow infundibulae. Calculi are associated with these cavities from 9.5 to 78% of cases (Liatsikos, et al 2000; Monga, et al 2000). This subset of stone-forming patients often presents with recurrent urinary tract infections and flank discomfort. The definitive treatment for this entity remains surgical, with shock wave lithotripsy (SWL), ureteroscopy (URS), percutaneous nephrolithotomy (PNL), and laparoscopy all serving as management options. However, multiple groups have demonstrated that PNL remains the treatment modality of choice secondary to its superior stone-free and symptom relief rates (Jones, et al 1991; Donnellan, et al 1999; Shalhav, et al 1998). Over time, technique modifications have been reported by other groups (Monga, et al 2000; Auge, et al 2002) involving different methods of managing the infundibulum that connects the diverticulum to the rest of the renal collecting system. Our own surgical experience with percutaneous treatment of stone-bearing caliceal diverticula has resulted in various technique modifications as well, which we believe have continued to improve patient outcomes. To support our hypothesis, we will need to perform a systematic review our patient population to document these surgical outcomes.

Another question surrounding this subset of patients involves the primary factor responsible for the formation of calculi within the diverticula. Unfortunately, the literature has provided conflicting data on this issue. Some groups attribute stone formation to underlying metabolic abnormalities (Hsu, et al 1998). Other groups have not found any metabolic problems, instead concluding that impaired urinary drainage from the diverticulum primarily contributes calculus formation (Liatsikos, et al 2000). By prospectively obtaining urines on our caliceal diverticula patients, we hope that detailed metabolic analyses will allow us to conclude definitively whether metabolic abnormalities are prevalent in this population.

INCLUSION CRITERIA:

1. Male or female patients over the age of 18 with symptomatic caliceal diverticular stone(s) who have had or require percutaneous treatment

EXCLUSION CRITERIA:

1. Patients unable to give informed consent
2. Patients with active bleeding diatheses
3. Women who are pregnant or in whom pregnancy status cannot be confirmed
4. Patients with renal insufficiency requiring dialysis
5. Patients with a baseline serum creatinine of 1.4 or greater