Lightning Podiums: Spinal Gumbo - 803A

Presented by: H. Elgafy

Author(s):

H. Elgafy(1), N. Lempert(1), J. Stirton(1), P. Zak(1)

(1) University of Toledo, Orthopedic, Toledo, OH, United States

Abstract

Introduction: Despite the well-published success of pedicle screw constructs, revision fixation is occasionally required, most commonly in cases of pseudoarthrosis. In the setting of revision surgery, a variable amount of pedicle bone loss may be present. This is a result of screw loosening and subsequent screw track widening following extraction of the original hardware. Often the bone quality may be poor secondary to aging, malnutrition, previous infection, smoking, or other medical comorbidities. 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, cannulated-fenestrated or expandable pedicle screws, and custom-made large diameter screws. Based upon the authors' review of the literature, using fibular allograft in the setting of revision pedicle screw fixation is a novel technique, without any prior published results.

Materials and Methods: 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 all four walls. The screw was advanced, and after full insertion of the screw, the fibular allografts were then trimmed.

Results: This technique was successfully used in 10 consecutive patients during revision lumbar spine surgeries for pseudoarthrosis. 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. Discussion and

Conclusions: 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 screws. Finally, this technique allows for biologic fixation at the screw-bone interface.