Predictors for Retrograde Ureteral Stenting Failure as an Initial Drainage Method for Emergent Complicated Acute Calculus Obstructive Uropathy

Objective To define predictors for initial retrograde ureteral stenting (RUS) failure with the need for thepercutaneous nephrostomy (PCN) insertion as a drainage method in patients with complicated acute calculusobstructive uropathy.Methods We undertook a retrospective evaluation of patients who presented with complicated obstructive calculusuropathy (acute renal failure or obstructive pyelonephritis) between January 2016 and January 2020. Patients in whomthere was failure to visualize ipsilateral ureteric orifice and those with extrinsic ureteral obstruction were excluded.Patient demographics and radiological data including stone site, hydronephrosis grade, maximum transverse stonediameter, periureteral density (PUD) and pericalcular ureteric thickness (P-CUT) at the maximum transverse stonediameter were assessed using non-contrast computed tomography at the time of admission.Results The study included 256 patients who were managed initially by RUS trial. Of them, 48 (18.8 %) had RUSfailure. The presence of acute pyelonephritis, increased maximum transverse stone diameter ≥ 9.5 mm, P-CUT ≥7.5 mm, and PUD at stone level ≥ 17.5 HU were risk factors associated with RUS failure (P = 0.007, 0.002, < 0.001,and < 0.001, respectively).Conclusion Initial radiological stone and ureteric characteristics, in addition to the clinical diagnosis of obstructivepyelonephritis, can be used to determine PCN insertion as the preferred option over RUS for urinary drainage.