Modified iliac screw technique for pelvic fixation: a scoping review of technical characteristics and early clinical outcomes

INTRODUCTION: Iliac screws remain essential in cases requiring spinopelvic fixation, providing distal anchorage and construct stability across many surgical indications. However, traditional posterior-superior-iliac-spine (PSIS) entry screws are associated with hardware prominence, postoperative pain, and the need for side-to-side connectors to link with primary rods. The S2 alar-iliac (S2AI) technique addresses these drawbacks but some series have reported higher mechanical failure rates due to acute screw angulation. Furthermore, the S2AI trajectory violates the sacroiliac (SI) joint, potentially limiting use in cases with compromised sacral anatomy. The modified iliac screw (MIS) technique was developed to overcome these issues by shifting the entry point medial to the PSIS, maintaining iliac purchase while avoiding SI joint involvement. This scoping review synthesizes early clinical usage and implant performance of this emerging technique. METHODS: A scoping review following PRISMA guidelines was conducted across PubMed, MEDLINE, and Embase through Sep 28, 2025. Eligible studies included reports describing patient outcomes following fixation using modified iliac screws. RESULTS: A total of 162 patients across 6 studies were included. The cohort had a mean age of 64.5 years (range; 18-78). The most common indication was deformity (62.3%; n = 101), followed by fixation following tumor resection (17.9%; n = 29) and degenerative disease (9.3%; n = 15). The mean number of fixed vertebrae was 8.01 (range; 3-18). Mean follow-up time was 19.19 months (range; 3-74). Implant complications were reported in 36 cases (22.2%), commonly screw perforation (n = 22), screw fracture (n = 5), and screw loosening (n = 4). Complications led to implant failure for 7 patient cases (4.3%). CONCLUSION: Early experiences with MIS fixation demonstrate promising clinical utility with acceptable rates of hardware-related complications and morbidity. However, existing evidence remains limited to small, heterogeneous series without standardized outcome reporting. Robust prospective investigations with larger cohorts and standardized long-term follow-up are needed to comprehensively characterize the safety, durability, and comparative performance of the MIS technique.