Prospective evaluation of outcome of percutaneous nephrolithotomy using the ‘STONE’ nephrolithometry score: a single-centre experience

Authors

Muhammad Farhan, Aga Khan UniversityFollow
Syed M. Nazim, Aga Khan University
Basit Salam, Aga Khan UniversityFollow
Hammad Ather, Aga Khan UniversityFollow

Document Type

Article

Department

Surgery; Urology

Abstract

Abstract

OBJECTIVE:

To assess the prediction of stone clearance and complications of percutaneous nephrolithotomy (PCNL) using the 'STONE' nephrolithometry score, assessing stone size, tract length (skin-to-stone distance), degree of obstruction, number of calyces involved and stone essence (density).

PATIENTS AND METHODS:

This was a prospective study of patients undergoing single-tract PCNL while prone, conducted at a university hospital. All patients had non-contrast-enhanced computed tomography within 3 weeks of the procedure. Only patients with a unilateral procedure and radio-opaque stones were included. The five variables of the STONE nephrolithometry score were calculated before the procedure. The stone-free rates were assessed with a plain abdominal film at 4 weeks and complications were graded using the modified Clavien system.

RESULTS:

In all, 107 patients were included in the final analysis. Overall, 80% of patients were rendered stone-free. Among the individual variables, a larger stone (P = 0.002) and the involvement of multiple calyces (P = 0.04) were associated with residual stones, while tract length (skin-to-stone distance), stone density and presence of hydronephrosis were not. Patients who were rendered stone-free had a statistically significant lower overall STONE score than those with residual stones, at 7.24 vs. 8.14 (P = 0.02). The score also correlated with operative duration, which was significantly longer with a higher STONE score (P = 0.03). The complication rate was 18% and most complications were Clavien grade 2, with bleeding requiring a blood transfusion (11 patients) being the commonest. There were no deaths within 30 days of surgery, but there was no correlation between the STONE score and complications.

CONCLUSION:

The STONE nephrolithometry score is a simple and easy to apply system for predicting complexity in stone clearance with PCNL.

Publication (Name of Journal)

Arab J Urol.

Recommended Citation

Farhan, M., Nazim, S., Salam, B., Ather, H. (2015). Prospective evaluation of outcome of percutaneous nephrolithotomy using the ‘STONE’ nephrolithometry score: a single-centre experience. Arab J Urol., 13(4), 264-269.
Available at: https://ecommons.aku.edu/pakistan_fhs_mc_surg_surg/592