PEEK-Halo effect in interbody fusion

Kevin Phan, Jarred A. Hogan, Yusuf Assem, Ralph J. Mobbs*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)


Recent developments have seen poly[aryl-ether-ether-ketone] (PEEK) being increasingly used in vertebral body fusion. More novel approaches to improve PEEK have included the introduction of titanium-PEEK (Ti-PEEK) composites and coatings. This paper aims to describe a potential complication of PEEK based implants relating to poorer integration with the surrounding bone, producing a "PEEK-Halo" effect which is not seen in Ti-PEEK composite implants. We present images from two patients undergoing anterior lumbar interbody fusion (ALIF). The first patient underwent an L5/S1 ALIF using a PEEK implant whilst the second patient underwent L4/L5 ALIF using a Ti-PEEK composite implant. Evidence of osseointegration was sought using CT imaging and confirmed using histological preparations of a sheep tibia model. The PEEK-Halo effect is demonstrated by a halo effect between the PEEK implant and the bone graft on CT imaging. This phenomenon is secondary to poor osseointegration of PEEK implants. The PEEK-Halo effect was not demonstrated in the second patient who received a Ti-PEEK composite graft. Histological analysis of graft/bone interface surfaces in PEEK versus Ti-PEEK implants in a sheep model further confirmed poorer osseointegration of the PEEK implant. In conclusion, the PEEK-Halo effect is seen secondary to minimal osseointegration of PEEK at the adjacent vertebral endplate following a PEEK implant insertion. This effect is not seen with Ti-PEEK implants, and may support the role of titanium in improving the bone-implant interface of PEEK substrates.

Original languageEnglish
Pages (from-to)138-140
Number of pages3
JournalJournal of Clinical Neuroscience
Publication statusPublished - 1 Feb 2016
Externally publishedYes


  • Anterior lumbar interbody fusion
  • Bone-implant interface
  • Osseointegration
  • PEEK
  • Titanium
  • Titanium coating


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