Journal of Pediatric Orthopaedics - 2026-03-04 - Journal Article
Is Two Better Than One? Pelvic Fixation Strategies in Neuromuscular and Early-onset Scoliosis: A Comparative Analysis of S1S2-iliac and S2-iliac Screws.
Obeid T, Espandar R, Rambo A, Upadhyay K, Epstein C, Larwa J, Lacoste K, Doshi M, Neal KM
Topics
Key Takeaway
Dual S1S2-iliac fixation achieved 64% major curve correction versus 53% with S2-iliac alone, but differences in pelvic obliquity correction and complication rates were statistically insignificant (P>0.4) in 77 neuromuscular/EOS patients.
Summary Depth
Choose how much analysis to show on this article page.
Summary
This study compared dual S1S2-iliac versus S2-iliac-only pelvic fixation in 77 NM/EOS patients undergoing spinal fusion with pelvic fixation. Both groups achieved similar major curve correction (64% vs. 53%, P=0.121) and pelvic obliquity reduction (17.5° to 6.3° vs. 11.1° to 4.5°). Complication rates (18% vs. 23%) and revision rates (4.5% vs. 9%) did not differ significantly between groups.
Key Limitation
The S1S2 group was substantially smaller (n=22 vs. n=55) with higher baseline pelvic obliquity, making the study underpowered to detect clinically meaningful differences in complication and correction outcomes.
Original Abstract
BACKGROUND
In patients with neuromuscular (NM) and early-onset scoliosis (EOS), spinal instrumentation and fusion treatments present significant challenges, particularly in achieving stable pelvic fixation and correcting pelvic obliquity (PO). This study aimed to evaluate whether dual sacroiliac (S1-iliac and S2-iliac) screw constructs improve PO correction and reduce complications compared with S2-iliac screws alone in patients with NM and EOS.
METHODS
A retrospective review of 77 patients with NM or EOS requiring pelvic fixation was conducted. Patients were divided into 2 groups: (1) bilateral S1-iliac and S2-iliac screws (S1-S2 group, n=22) and (2) bilateral S2-iliac screws alone (S2 group, n=55). Preoperative and postoperative major curves and PO were assessed, along with complication rates, including implant prominence, screw pullout, breakage, infection, and revision surgery.
RESULTS
Both groups achieved similar main curve corrections at final follow-up (S2=53%, S1-S2=64%, P =0.121). The mean preoperative major curve for the S2 and S1-S2 groups was 63.7 degrees (range 20 to 106 degrees) and 68.9 degrees (range 39 to 135 degrees), respectively. At final follow-up, the mean curve measured 29.4 degrees (range 3 to 82 degrees) and 23.4 degrees (range 7 to 48 degrees), corresponding to 54% and 66% correction, respectively. Preoperative PO averaged to 11.1 degrees (range 0 to 36 degrees) and 17.5 degrees (range 2 to 36 degrees) in S2 and S1-S2 groups, respectively. At final follow-up, PO measured 4.5 degrees (range -3 to 23 degrees) and 6.3 degrees (range 0 to 15 degrees), respectively. In all, 18% (4/22) of patients in the S1S2 group and 23% (13/55) of patients in the S2 group showed complications. Implant breakage occurred in 1 patient in the S1S2 group and 7 in the S2 group ( P =0.427). Revision surgery was required in 5 patients in the S2 group and 1 in the S1S2 group ( P =0.668).
CONCLUSIONS
Bilateral S1S2-iliac screws were successfully placed and provided early improvements in PO correction compared with S2-iliac screws alone. However, differences in PO correction and complication rates were statistically insignificant at final follow-up. Further prospective studies with larger cohorts and longer follow-up are needed to assess potential long-term biomechanical advantages of dual fixation.
LEVEL OF EVIDENCE
Level III.