Table 5.

Degree of stone burden.

Characteristics	Value	95% CI of mean
Total no. stone events	79	–
Mean age at first stone event at institution (years)	22.83 (3.9–60.5)	19.95–25.72
Mean number of events	1.48 (1–4)	1.3–1.65
Mean size of stone burden per event (cm)	2.17 (0.1–9.3)	1.65–2.69
No. bilateral stone events (%)	30 (38%)	–
No. events with surgery required (%)	48 (60%)	–
No. patients requiring at least one PCNL (%)	30 (38%)	–
No. patients requiring multiple PCNL (%)	18 (22%)	–

PCNL, percutaneous nephrolithotomy.