Is spinal anesthesia a safe alternative for retrograde intrarenal surgery for stone disease in daily practice?

Objectives: Retrograde intrarenal surgery (RIRS) is commonly performed under general anesthesia (GA) because renal mobility during breathing may affect lithotripsy. However, spinal anesthesia (SA) is adopted in clinical practice due to clinical conditions that contraindicate GA. We aimed to compare results of RIRS for stones performed under GA compared to SA regarding stonefree rate (SFR) status and postoperative complications in a consecutive single-center series. Methods: We retrospectively reviewed all patients who underwent RIRS for stones between 2017 and 2020. Inclusion criteria: age >= 18 years, renal stone burden deemed suitable for RIRS with a stone diameter <= 20 mm. Exclusion criteria: stones >20 mm, urinary tract infection, bilateral surgery, second-look procedures, unmodifiable bleeding diathesis, <5mm asymptomatic lower calyx stones. SFR was defined as no residual fragment >3 mm at 6-12 weeks follow-up. The choice of anesthesia was a shared decision between anesthesiologists and patient preference. Results: 230 patients were included in the analysis. Mean age was 57.50 +/- 13.73 years. 33% of stones were located in the pelvis. 28.7% of patients had multiple stones. Mean cumulative stone diameter was 16.60 +/- 6.54 mm. 63% of patients underwent RIRS under SA. There were no significant differences between the two groups in terms of preoperative characteristics, except for comorbidity, significantly higher in the GA group. Mean time of operating room occupation was longer in the GA group (81.58 +/- 35.37 minutes) than in the SA group (72.85 +/- 25.91 minutes,p=0.033). Length of stay was shorter in the SA group (mean 2.2 +/- 1.66 days vs 3.46 +/- 5.88 in GA,p=0.019). Logistic regression showed that multiple stones in the collecting system were associated with residual fragments (HR 0.386, 95%CI 0.151-0.991,p=0.04). There were no statistically significant differences in overall and high-grade complications, and in SFR between SA (75.9%) and GA groups (70.6%,p=0.317). Conclusion: SA does not affect SFR and postoperative complications in patients who underwent RIRS in daily practice.