stone_nephrolithometry_score: STONE Nephrolithometry Score

In cliot: Clinical Indices and Outcomes Tools

STONE Nephrolithometry Score

Description

Calculates the S.T.O.N.E. Nephrolithometry Score to predict the complexity of Percutaneous Nephrolithotomy (PCNL) and estimated stone-free rates. The score is based on 5 parameters: Stone size, Tract length, Obstruction, Number of involved calyces, and Essence (stone density).

Usage

stone_nephrolithometry_score(stone_size_mm2, tract_length_mm, obstruction_degree,
                             number_involved_calyces, stone_density_hu)

Arguments

stone_size_mm2	Numeric. Stone surface area in mm^2 (typically Length x Width x pi x 0.25). <400: 1 pt. 400-799: 2 pts. 800-1599: 3 pts. >=1600: 4 pts.
tract_length_mm	Numeric. Skin-to-stone distance in mm (average of 3 distances on CT). <=100: 1 pt. >100: 2 pts.
obstruction_degree	String. Degree of hydronephrosis. "none_mild": 1 pt. "moderate_severe": 2 pts.
number_involved_calyces	String. Number of calyces containing stones. "1_or_2": 1 pt. "3": 2 pts. "staghorn": 3 pts.
stone_density_hu	Numeric. Stone density in Hounsfield Units. <=950: 1 pt. >950: 2 pts.

Value

A list containing:

STONE_Score	The calculated total score (Range 5-13).
Surgical_Complexity	Classification (Low, Moderate, High).
Est_Stone_Free_Rate	Estimated likelihood of achieving stone-free status.

References

Okhunov Z, Friedlander JI, George AK, et al. S.T.O.N.E. nephrolithometry: novel surgical classification system for kidney calculi. Urology. 2013;81(6):1154-1159. doi:10.1016/j.urology.2012.10.083

Examples

# Example 1: Low Complexity
# 300mm2, 80mm tract, Mild Hydro, 1 calyx, 800 HU
# Score = 1 + 1 + 1 + 1 + 1 = 5
stone_nephrolithometry_score(300, 80, "none_mild", "1_or_2", 800)

# Example 2: High Complexity
# 1700mm2, 120mm tract, Severe Hydro, Staghorn, 1200 HU
# Score = 4 + 2 + 2 + 3 + 2 = 13
stone_nephrolithometry_score(1700, 120, "moderate_severe", "staghorn", 1200)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.