Isobaric chloroprocaine spinal anesthesia versus general anesthesia and hyperbaric prilocaine spinal anesthesia for ambulatory pilonidal sinus surgery in the prone position: a retrospective single-center cohort study

Background Pilonidal sinus surgery is commonly performed on an ambulatory basis in the prone position. General anesthesia may be associated with positioning-related complications and organizational challenges. Short-acting spinal anesthesia with chloroprocaine may facilitate positioning and enhance recovery. This study evaluated the feasibility and organizational impact of isobaric chloroprocaine spinal anesthesia compared with general anesthesia and hyperbaric prilocaine. Methods This retrospective single-center cohort study included patients undergoing ambulatory pilonidal sinus surgery in the prone position between January 2023 and February 2026. Patients received general anesthesia, isobaric chloroprocaine spinal anesthesia or hyperbaric prilocaine spinal anesthesia. The primary outcome was time to readiness for discharge, analyzed using Kaplan–Meier estimates and a parametric accelerated failure time model. Results A total of 226 patients were analyzed: 103 received chloroprocaine spinal anesthesia, 28 prilocaine spinal anesthesia and 95 general anesthesia. Median time to readiness for discharge was 192 min (IQR 173–237) with chloroprocaine, compared with 235 min (IQR 202–276) with general anesthesia and 299 min (IQR 284–348) with prilocaine (log-rank; p < 0.001). Compared with general anesthesia, time to readiness for discharge was shorter with chloroprocaine (time ratio 0.87, 95% CI 0.81 to 0.94; p < 0.001) and, although exploratory, longer with prilocaine (time ratio 1.32, 95% CI 1.18 to 1.48; p < 0.001). No conversion to general anesthesia occurred after successful spinal anesthesia; one intended prilocaine spinal anesthesia could not be performed for technical reasons. Conclusions Isobaric chloroprocaine spinal anesthesia was associated with shorter time to readiness for discharge than general anesthesia while appearing feasible for ambulatory pilonidal sinus surgery in the prone position. These findings warrant confirmation in prospective studies. Clinical trial number Not applicable.