INTRODUCTION AND OBJECTIVES: The S.T.O.N.E. nephrolithometry
was previously developed to quantitate stone
complexity and predict outcomes of PCNL. We sought to assess
the ability of nephrolithometry score to predict perioperative
variables in a multicenter database of patients undergoing PCNL.
METHODS: We performed a multicenter review of patients
undergoing PCNL. Preoperative CT images were reviewed and
S.T.O.N.E. score was assigned to each patient. The association of
S.T.O.N.E. score with patient demographics, stone characteristics
and surgical outcomes was performed.
RESULTS: Total of 706 patients were included in the analysis.
The mean overall nephrolithometry score was 8.2 (range 5–13).
Overall complication rate was 18%. Bleeding and sepsis were the
most frequent complications. S.T.O.N.E. score was significantly
associated with overall complication rate (P = 0.008), EBL
(P = 0.001), and operative time (P < 0.001), and length of stay
(P = 0.016). For each point increase in the score there is a 12.6mL
increase in EBL. For each point increase in the score there is a
10.7 min increase in OR time. In risk stratification, medium-risk
patients (8–10) and high-risk patients (11–13) had significantly
higher EBL and OR time compared to low-risk patients with 5–7
scores (mean EBL 139, 197 and 134, OR time 132, 170 and 102,
respectively, p = 0.001). Scoring system was not predictive of
transfusion rates and fluoroscopy time in this cohort.
CONCLUSIONS: Our multicenter data demonstrated that
S.T.O.N.E. nephrolithometry accurately predicted surgical
outcomes following PCNL, including overall complications,
EBL and operative time. The scoring system obtained from
computed tomography imaging may be effectively used in
preoperative patient counseling and prediction of PCNL outcomes.