Evaluation and comparison of S.T.O.N.E. and Guy's scoring systems for predicting percutaneous nephrolithotomy outcomes in supine position

Abstract

Background: Percutaneous nephrolithotomy (PCNL) was applied in the prone position until recently. But also, in recent years supine positions was applied in patients with kidney stones. Predicting how much renal stones can be cleared after surgery and possibility of complications is an important question for both surgeons and patients. Therefore different scoring systems are used to evaluate outcomes of PCNL before surgery.

Patients and methods: Between 2018 and 2020, 80 patients with renal stone who underwent PCNL in the supine position were evaluated preoperatively by S.T.O.N.E. and Guy's scoring systems (GSS). The predictions of both scoring systems for stone-free and complication rates in patients who underwent PCNL in the supine position were evaluated. Also, these scoring systems were compared among themselves for reliability.

Result: In both scoring systems, there was a statistically significant difference between postoperative stone-free (SF) and residual stone (RS) of patients and in predicting the likelihood of complications in patients. No statistically significant difference was found between the two scoring systems in predicting the stone-free rate.

Conclusion: Our findings revealed that S.T.O.N.E. nephrolithometry and Guy's score systems can be used effectively to predict stone-free rate, complications, and operation duration in supine position PCNL for renal stones.

Keywords: Guy’s stone score; Percutaneous nephrolithotomy; S.T.O.N.E. nephrolithometry; stone-free rate; supine position.