KUMJ | VOL. 22 | NO. 1 | ISSUE 85 | JANUARY - MARCH
Predictors of Stone Free Rate and Application of the Size, Topography, Obstruction, Number and Evaluation of Hounsfield Units (S.T.O.N.E) Scoring System in Predicting the Outcome in Patients Undergoing Semi-rigid Ureteroscopic Lithotripsy for Ureteric Calculi at a University Hospital of Nepal
Shrestha B, Koju R, Makaju Shrestha S, Shrestha K, Karmacharya RM
Abstract: Background
Ureteric colic is common urological emergency in patients with urinary stone disease.
Semi rigid ureteroscopic lithotripsy is a widely acceptable treatment modality for
ureteric calculi.
Objective
To evaluate the predicting factors of stone free rate (SFR) and application of the Size,
Topography, Obstruction, Number and Evaluation of Hounsfield units (S.T.O.N.E)
scoring system in predicting success rate of ureteroscopiclithotrisy (URSL) for ureteric
calculi.
Method
This was a prospective hospital based observational study conducted at the
Department of Surgery, Dhulikhel Hospital, Kathmandu University Hospital from
October 2021 to September 2022. Patients undergoing ureteroscopiclithotripsy
using laser and/or pneumatic lithotripsy for ureteric calculi were included in the
study. Informed consent was taken from each patient and data collection was done
by filling the proforma.
Result
A total of 82 patients were included in the study. Mean age of patients was 35.89
± 11.51 years. Overall stone free rate was 80.5%. Stone free rate were 96.67% and
71.15% in moderate (6-9) and high (10-13) S.T.O.N.E score groups respectively.
Stone size and S.T.N.O.E score were found to be significantly high in patients with
retained stone following ureteroscopiclithotrisy (p value < 0.05). Duration of surgery
was significantly high in high S.T.O.N.E score group (p<0.05). However no significant
correlation was found between patient characters like age, sex, Body mass index and
Hounsfield units of stone with stone free rate in this study. The area under the curve
of the receiver operating characteristic curve for the S.T.O.N.E score and stone size
were 0.693 and 0.660 respectively in this study.
Conclusion
Stone size and S.T.O.N.E score can be used as predictors of success following semi-
rigid ureteroscopic lithotripsy. The value of S.T.N.O.E score has good predictive value
for SFR and duration of surgery. There was no significant impact of patient’s age,
sex, Body mass index and Hounsfield units of stone in stone free rate following
ureteroscopic lithotrisyin this study.
Keyword : Body mass index, Lithotripsy, Receiver operating characteristic curve, Ureteroscopy
