INTRODUCTION: Anterior column support at L5‐S1 to lower the pseudarthrosis rate in long segment fusions has traditionally been performed through open ALIF, TLIF or PLIF
METHODS: We report on 97 consecutive patients post AxiaLIF L5‐S1 fusion at the end of a long segment construct performed over the last 4 years at 2 major spine centers. 21 had 2‐level AxiaLIF at L5‐S1 and L4‐5. All had 3 or more levels fused above the AxiaLIF level. 63 had fusions extending above the TL junction with 20 of these patients fused into the proximal thoracic spine. Fusion was augmented with local bone, RhBMP2 (Infuse) and DBM. VAS, TIS, SF‐36, ODI and X‐rays were recorded.
RESULTS: Mean follow up was 24 months (range:1 to 44). 71 pts have > 1 year FU with 37 > 2 years and 21 > 3 years FU. Mean patient age was 62 (range:22 to 81). Preop diagnoses included scoliosis (68 pts) and multilevel degenerative disc disease (29 pts). Clinical and Functional outcomes are charted below. At 1 yr solid fusion, was noted in 67/71 pts, with CT confirmation in 56. There were no intraoperative complications. Only 14 pts had iliac bolt fixation. One Iliac bolt was revised due to a broken screw. There have been no bowel injuries, sacral fractures or pedicle screw failures. There were two pseudarthroses at L5‐S1. There was one late infection with non‐union and one other had sacral pedicle screw loosening. There were 4 pts with superficial wound dehiscence. One patient had a malpositioned AxiaLIF screw causing radiculopathy. (cont'd)
DISCUSSION: AxialLIF may be a viable alternative for providing anterior column support for long segment fusions to the sacrum. Majority were not instrumented to the ilium and have shown solid fusion with maintenance of correction up to three years. The absence of distal implant failure may attest to the biomechanical strength of the L5‐S1 construct. More importantly the clinical outcomes suggest that with the AxiaLIF bolt, iliac screw fixation may not be necessary in long constructs.