Impact of Vacuum-Assisted Mini-Endoscopic Combined Intrarenal Surgery for Staghorn Stones: Analysis of Perioperative Factors of Postoperative Fever and Stone-Free Status

Background and Objective: This retrospective cohort study aimed to evaluate the clinical outcomes of vacuum-assisted mini-endoscopic combined intrarenal surgery (vmECIRS) for staghorn stones. Patients and Methods: We analyzed a total of 61 cases treated with initial vmECIRS using 14F/16F ClearPetra® percutaneous sheaths for staghorn stones. We primarily measured complications and stone-free rates (SFRs) to evaluate the safety and efficiency of vmECIRS. In addition, pre- and intraoperative factors in patients who experienced postoperative fever >38°C and achieved an initial stone-free status were evaluated. Results: The percentages of staghorn stones were 36.1% and 63.9% for complete and partial stones, respectively. The median stone volume was 8.48 cm3. The median operation time was 117 minutes, and the mean number of procedures was 1.54. Regarding postoperative complications, postoperative fever >38°C was reported in 18 patients (29.5%). The initial and final SFRs were 50.8% and 91.8%, respectively. Among patients with emerging fever >38°C, positive urine culture was the only significant risk factor in the multivariate analysis (odds ratio [OR], 7.500; 95% confidence interval [CI], 1.772-31.751; p = 0.006). Moreover, for achieving initial stone-free status, body mass index and stone volume were significant risk factors in the multivariate analysis (OR, 0.872; 95% CI, 0.776-0.980; p = 0.021; and OR, 0.882; 95% CI, 0.784-0.994; p = 0.039, respectively). Conclusions: These findings suggest that vmECIRS is safe and effective for treatment of staghorn stones. Although current guidelines suggest that percutaneous nephrolithotomy is the gold standard surgical technique for staghorn stones, vmECIRS could also be a treatment strategy. The Clinical Trial Registration number (ID: 2022-05-17-1).