Study design: Retrospective cohort study.
Objective: To report the clinical and radiological outcomes for screw track augmentation with fibular allograft in revision of loose pedicle screws associated with significant bone loss along the screw track.
Methods: Thirty consecutive patients, 18 men (60%) and 12 women (40%), with a mean age 52 years (range 34- 68). Fibular allograft was prepared by cutting it into longitudinal strips 50 mm in length. Three allograft struts were inserted into the screw track. Six mm tap used to tap between the 3 fibular struts. Eight- or 9-mm diameter, and 45 or 50 mm in length screw was then inserted. The clinical outcomes were assessed by means of the Oswestry Disability Index (ODI), and visual analog scale (VAS) for back and leg pain for clinical outcome. Computed tomography scan (CT) performed at 12 months postoperative visit to assess fibular graft incorporation along the pedicle screw track, any screw loosening and the interbody as well as posterolateral fusion.
Results: At a mean follow up of 29 months, there were statically significant improvement in the ODI and VAS for back and leg pain. CT scan obtained at last follow-up showed incorporation of fibular allograft and solid fusion in all patients except one.
Conclusion: The fibular allograft augmentation of the pedicle screw track in revision of loose pedicle screws associated with significant bone loss is a viable option. It allows for biologic fixation at the screw-bone interface and has some key advantages when compared to currently available methods.
Keywords: bone loss; fibular allograft; loose pedicle screw; pseudoarthrosis.