LAUSR

OBJECTIVE The modified iliac screw fixation technique was proposed to be an interesting alternative option for spinopelvic fixation. In this study, we describe a new minimally invasive technique for percutaneous placement of modified iliac screws. METHODS A 64-year-old male with ankylosing spondylitis suffered from a 3-column fracture at the L5 vertebra without any neurological deficit. We performed percutaneous pedicle screw fixation from L2 to S1 with additional modified iliac screws augmentation using an intraoperative navigation. We inserted both S1 pedicle screw and modified iliac screw within a stab incision on each side of the patient's back without using rod connector. RESULTS The patient's severe low back pain was subsided on the day following the operation. There was no clinical low back pain at 2-week follow-up. The 1-year follow-up x-ray showed that the fracture was healed successfully without sign of screw loosening or breakage. CONCLUSIONS The modified iliac screws can be placed safely via percutaneous approach with an intraoperative image guidance. By using this new technique, surgeons can easily adjust the screw head to align with S1 pedicle screw via the same small incision. The rod connectors are not necessary for this technique. This method also prevents the acute angle that can develop between the screw head and shaft of the screw which is typically found in S2AI screw technique.