“Within ring”-based sacroiliac rod fixation may overcome the weakness of spinopelvic fixation for unstable pelvic ring injuries: technical notes and clinical outcomes

Purpose Spinopelvic fixation and triangular osteosynthesis give firm internal fixation for unstable pelvic ring injuries (UPRI), but with sacrifice of mobility of the lumbar spine. Here, we describe the procedure and outcomes of a new approach, which we refer to as “within ring”-based sacroiliac rod fixation (SIRF). Methods The patient was placed in a prone position and longitudinal skin incisions were made at the medial margins of the bilateral posterior superior iliac spines (PSIS). After reduction of fracture, a pedicle screw was inserted into the first sacral vertebra on the injured side and iliac screws inserted through the bilateral PSIS were bridged using rods. Results SIRF was performed in 15 patients. The AO/OTA classification was 61-B2.3 in 1, C1.3 in 4, C2.3 in 7, C3.3 in 1, and H-type spinopelvic dissociation in two cases. The mean operative time was 179 (110–298) minutes, mean blood loss was 533 (100–2700) cc. One patient died during hospitalization and three patients stopped outpatient treatment. The other 11 patients achieved bone union without major loss of reduction in a mean post-operative follow-up period of 23.8 (4–50) months. The mean Majeed score at final follow-up was 86.7 (73–96) out of 96, excluding scoring sexual intercourse. Conclusions “Within ring”-based SIRF not including the lumbar spine in the fixation range is a simple, safe, and low-invasive internal fixation method for UPRI.