Variability of S1 and S2 Intrasacral Corridor Height in Cone-Beam Computed Tomography-Guided Percutaneous Pelvic Screw Fixation: A Retrospective Study of 115 Patients.

PURPOSE: To test the hypothesis that S1 and S2 intrasacral corridor height shows substantial interindividual variability but is not associated with operative time or radiation exposure in patients undergoing cone-beam computed tomography (CT)-guided percutaneous pelvic osteosynthesis.

MATERIALS AND

METHODS

This retrospective single-center study included 115 consecutive patients treated between March 2023 and November 2025 with cone-beam CT-guided percutaneous pelvic screw fixation for traumatic or fragility fractures. Patients who received at least 1 screw in an S1 and/or S2 intrasacral corridor were included. Corridor height was measured on follow-up CT using standardized multiplanar true outlet reconstructions. The primary end point was to explore the variability of corridor height. Secondary end points were to assess operative time, radiation exposure, and adverse events.

RESULTS

A total of 169 screws were inserted in 115 patients (median age, 67 years). Median intrasacral corridor height was 23 mm (interquartile range, 21-26 mm), with a minimum of 10 mm and a maximum of 32 mm. Median operative time was 47 minutes, and median dose-area product was 78.8 Gy·cm2. No significant correlation was observed between corridor height and operative time (Spearman ρ = 0.043; P = .65) or radiation exposure (Spearman ρ = -.057; P = .55). One adverse event (0.6%) was reported, not associated with smaller corridor height.

CONCLUSIONS

S1 and S2 intrasacral corridors exhibit substantial anatomical variability. In this cohort of cone-beam CT-guided percutaneous pelvic osteosyntheses, corridor height did not influence operative time or radiation exposure. One adverse event was observed. These findings suggest that 3-dimensional cone-beam CT planning may facilitate safe and efficient screw placement despite sacral anatomical variations.