Risk factors for developing a perirenal hematoma after flexible ureteroscopic lithotripsy

Objective: To investigate the risk factors of perirenal hematoma (PRH) after flexible ureteroscopic lithotripsy (FURSL). Materials and methods: We retrospectively reviewed the medical records of 45 patients who underwent FURSL with a holmium: yttrium-aluminum-garnet laser. We divided all patients in two groups: the PRH group and the non-PRH group. The patient demographic and baseline characteristics, surgical outcomes, and complications were compared and risk factors were identified and analyzed. Results: Of the 45 consecutive patients treated with FURSL, four (8.9%) developed PRH. Compared with patients without PRH, patients with PRH had a lower body mass index (BMI; 20.2 +/- 3.2 kg/m(2) vs 26.9 +/- 5.5 kg/m(2), p - 0.015), thinner kidney cortex thickness (0.88 +/- 0.41 cm vs 1.39 +/- 0.41 cm, p = 0.024), and a history of chronic kidney disease (CKD; 75% vs 14.6%, odds ratio = 17.5, confidence interval = 1.55-197.46, p = 0.021). However, patient age, diabetes mellitus, hypertension, liver disease, coronary artery disease, history of urolithiasis, presence of multiple stones, and stone size and location were comparable in both groups. Three patients with PRH were successfully managed with conservative treatment. One patient with PRH underwent an emergency nephrectomy within 1 day but died 2 weeks later despite vigorous resuscitation. Conclusion: Among our patients, those with lower BMI, CKD, and a thinner renal cortex had a higher risk of developing PRH after FURSL. Endourologists should have a heightened awareness for potential PRH when treating patients who present with low BMI, CKD, and a thin renal cortex. Copyright (C) 2015, Taiwan Urological Association. Published by Elsevier Taiwan LLC.