Does PEEK/HA Enhance Bone Formation Compared With PEEK in a Sheep Cervical Fusion Model?

William R Walsh,Nicky Bertollo,Chris Tan,Matthew H Pelletier,Chris Christou

doi:10.1007/s11999-016-4994-x

William R Walsh, Nicky Bertollo + Show 3 more

Open Access

https://doi.org/10.1007/s11999-016-4994-x

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Abstract

BackgroundPolyetheretherketone (PEEK) has a wide range of clinical applications but does not directly bond to bone. Bulk incorporation of osteoconductive materials including hydroxyapatite (HA) into the PEEK matrix is a potential solution to address the formation of a fibrous tissue layer between PEEK and bone and has not been tested.Questions/purposesUsing in vivo ovine animal models, we asked: (1) Does PEEK-HA improve cortical and cancellous bone ongrowth compared with PEEK? (2) Does PEEK-HA improve bone ongrowth and fusion outcome in a more challenging functional ovine cervical fusion model?MethodsThe in vivo responses of PEEK-HA Enhanced and PEEK-OPTIMA® Natural were evaluated for bone ongrowth in the form of dowels implanted in the cancellous and cortical bone of adult sheep and examined at 4 and 12 weeks as well as interbody cervical fusion at 6, 12, and 26 weeks. The bone-implant interface was evaluated with radiographic and histologic endpoints for a qualitative assessment of direct bone contact of an intervening fibrous tissue later. Gamma-irradiated cortical allograft cages were evaluated as well.ResultsIncorporating HA into the PEEK matrix resulted in more direct bone apposition as opposed to the fibrous tissue interface with PEEK alone in the bone ongrowth as well as interbody cervical fusions. No adverse reactions were found at the implant–bone interface for either material. Radiography and histology revealed resorption and fracture of the allograft devices in vivo.ConclusionsIncorporating HA into PEEK provides a more favorable environment than PEEK alone for bone ongrowth. Cervical fusion was improved with PEEK-HA compared with PEEK alone as well as allograft bone interbody devices.Clinical RelevanceImproving the bone–implant interface with a PEEK device by incorporating HA may improve interbody fusion results and requires further clinical studies.

Highlights

Interbody spinal fusion has a long history from the pioneering works of Cloward [10] and Babgy [1]
We hypothesized that the incorporation of HA into the PEEK matrix would enhance in vivo response at the bone– implant interface
Using in vivo ovine animal models, we asked: (1) Does PEEKOPTIMA1 HA Enhanced (PEEK-HA) improve cortical and cancellous bone ongrowth compared with PEEK? (2) Does PEEK-HA improve bone ongrowth and fusion outcome in a more challenging functional ovine cervical fusion model? The null hypothesis was that there were no differences between the different materials at the bone–implant interface

Summary

Introduction

Interbody spinal fusion has a long history from the pioneering works of Cloward [10] and Babgy [1]. Polyetheretherketone (PEEK) is a biocompatible semicrystalline thermoplastic polymer that has a wide range of clinical applications [29]. Polyetheretherketone (PEEK) has a wide range of clinical applications but does not directly bond to bone. Questions/purposes Using in vivo ovine animal models, we asked: (1) Does PEEK-HA improve cortical and cancellous bone ongrowth compared with PEEK? (2) Does PEEK-HA improve bone ongrowth and fusion outcome in a more challenging functional ovine cervical fusion model? Methods The in vivo responses of PEEK-HA Enhanced and PEEK-OPTIMA1 Natural were evaluated for bone ongrowth in the form of dowels implanted in the cancellous and cortical bone of adult sheep and examined at 4 and 12 weeks as well as interbody cervical fusion at 6, 12, and 26 Questions/purposes Using in vivo ovine animal models, we asked: (1) Does PEEK-HA improve cortical and cancellous bone ongrowth compared with PEEK? (2) Does PEEK-HA improve bone ongrowth and fusion outcome in a more challenging functional ovine cervical fusion model? Methods The in vivo responses of PEEK-HA Enhanced and PEEK-OPTIMA1 Natural were evaluated for bone ongrowth in the form of dowels implanted in the cancellous and cortical bone of adult sheep and examined at 4 and 12 weeks as well as interbody cervical fusion at 6, 12, and 26

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Conclusion