Predictors of Proximal Stone Migration During Ureteroscopic Pneumatic Lithotripsy For Proximal Ureteric Calculi: A Retrospective Study

Abstract

Background:
Proximal stone migration during semirigid ureteroscopic pneumatic lithotripsy is a common cause of procedural failure, resulting in reduced stone-free rates and increased need for secondary interventions. Identifying factors associated with stone migration may help improve surgical planning and outcomes.

Aim:
To evaluate the predictors of proximal stone migration during ureteroscopic pneumatic lithotripsy in patients with proximal ureteric calculi.

Methods:
This retrospective observational analytical study included 150 adult patients who underwent semirigid ureteroscopic pneumatic lithotripsy for a single proximal ureteric calculus. Demographic, clinical, radiological, operative, and postoperative data were collected from hospital records. Patients were categorized into migration and non-migration groups. Univariate analysis followed by multivariable logistic regression was performed to identify independent predictors of proximal stone migration. Statistical significance was considered at p<0.05.

Results:
Proximal stone migration occurred in 31 patients (20.7%). Patients with migration had significantly larger stones (13.9 ± 2.8 mm vs. 10.8 ± 2.5 mm; p<0.001), higher stone density (1125 ± 180 HU vs. 945 ± 165 HU; p<0.001), a greater incidence of impacted stones (74.2% vs. 37.8%; p<0.001), and more moderate-to-severe hydronephrosis (61.3% vs. 29.4%; p=0.002). The migration group had significantly lower stone-free rates (38.7% vs. 95.8%; p<0.001), higher rates of secondary procedures (71.0% vs. 4.2%; p<0.001), and more complications (25.8% vs. 8.4%; p=0.009). Multivariable logistic regression identified stone size ≥12 mm (OR 3.82; p=0.002), impacted stone (OR 3.11; p=0.011), stone density ≥1000 HU (OR 2.68; p=0.019), and non-use of an anti-retropulsion device (OR 4.27; p=0.003) as independent predictors of proximal stone migration.

Conclusion:
Proximal stone migration occurred in approximately one-fifth of patients undergoing semirigid ureteroscopic pneumatic lithotripsy. Larger stone size, higher stone density, stone impaction, and non-use of anti-retropulsion devices were independent predictors of migration. Early identification of high-risk patients and the selective use of anti-retropulsion devices may improve stone-free rates and reduce the need for secondary procedures.