Fibular Allograft as a Salvage Option in Revision Pedicle Screw Fixation

Global SpineJ 2023 March30;13(2):409-415. Hossein Elgafy, Nathaniel Lempert, Jacob Stirton, Peter Zak, MD

Purpose:

In the setting of revision spine surgery for pseudoarthrosis, a variable amount of pedicle bone loss may be present. This is a result of screw loosening and subsequent screw track widening. Often the bone quality may be poor secondary to aging, malnutrition, previous infection, and smoking. In these difficult cases, multiple techniques have been utilized to enhance the construct strength. Current options for revision pedicle screw fixation include cement augmented screw fixation and custom-made large diameter screws. The purpose of this study was to present the authors’ experience using fibular allograft in the setting of bone loss with loose pedicle screw revision.

Method:

In patients with extensive screw track dilation, fibular allograft was obtained and cut into small, longitudinal strips—approximately 3mm in thickness. The length of each fibular allograft strut was trimmed to coincide with the length of the former screw, allowing for overhang. Allograft strut was inserted into the screw track along the wall. The screw was then advanced between the allograft, and after full insertion of the screw, the fibular allografts were then trimmed.

Results:

All patients had loose pedicle screws with significant bone loss around the screw tracks. Excellent purchase was achieved in all patients. CT scan at the last follow up showed incorporation of the fibular allograft and sound fusion in all patients except one.

Conclusion:

Fibular allograft is a viable option in the setting of revision pedicle screw fixation and has several advantages when compared to currently available methods. It avoids the complications associated with cement augmented pedicle screws. In addition, it can be used impromptu, when other options are not immediately available. This technique can be employed without specialized instrumentation at significant cost savings when compared to custom made screws. Finally, this technique allows for biologic fixation at the screw-bone interface.