title: Effect of Polyether Ether Ketone on Therapeutic Radiation to the Spine: A Pilot Study.
abstract: METHODS
  Cadaveric model.
  
  
  OBJECTIVE
  To compare the effect of PEEK versus conventional implants on scatter radiation to a simulated tumor bed in the spine SUMMARY OF BACKGROUND DATA.: Given the highly vasculature nature of the spine, it is the most common place for bony metastases. After surgical treatment of a spinal metastasis, adjuvant radiation therapy is typically administered. Radiation dosing is primarily limited by toxicity to the spinal cord. The scatter effect caused by metallic implants decreases the accuracy of dosing and can unintentionally increase the effective dose seen by the spinal cord. This represents a dose-limiting factor for therapeutic radiation postoperatively.
  
  
  METHODS
  A cadaveric thorax specimen was utilized as a metastatic tumor model with two separate three-level spine constructs (one upper thoracic and one lower thoracic). Each construct was examined independently. All four groups compared included identical posterior instrumentation. The anterior constructs consisted of either: an anterior polyether ether ketone (PEEK) cage, an anterior titanium cage, an anterior bone cement cage (polymethyl methacrylate), or a control group with posterior instrumentation alone. Each construct had six thermoluminescent detectors to measure the radiation dose.
  
  
  RESULTS
  The mean dose was similar across all constructs and locations. There was more variability in the upper thoracic spine irrespective of the construct type. The PEEK construct had a more uniform dose distribution with a standard deviation of 9.76. The standard deviation of the others constructs was 14.26 for the control group, 19.31 for the titanium cage, and 21.57 for the cement (polymethyl methacrylate) construct.
  
  
  CONCLUSIONS
  The PEEK inter-body cage resulted in a significantly more uniform distribution of therapeutic radiation in the spine when compared with the other constructs. This may allow for the application of higher effective dosing to the tumor bed for spinal metastases without increasing spinal cord toxicity with either fractionated or hypofractionated radiotherapy.
  
  
  METHODS
  N/A.
authors.affiliation: Department of Orthopedics, University of South Carolina, Columbia, SC.
authors.forename: J Benjamin
authors.initials: JB
authors.lastname: Jackson
authors.affiliation: Department of Radiation Oncology, Levine Cancer Institute, Carolinas HealthCare System, Charlotte, NC.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Crimaldi
authors.affiliation: Orthopedic Engineering Research, Carolinas Medical Center, Charlotte, NC.
authors.forename: Richard
authors.initials: R
authors.lastname: Peindl
authors.affiliation: Dickson Advanced Analytics, Carolinas HealthCare System, Charlotte, NC.
authors.forename: H James
authors.initials: HJ
authors.lastname: Norton
authors.affiliation: Dickson Advanced Analytics, Carolinas HealthCare System, Charlotte, NC.
authors.forename: William E
authors.initials: WE
authors.lastname: Anderson
authors.affiliation: Department of Orthopedic Surgery, Carolinas Medical Center, Levine Cancer Institute, Charlotte, NC.
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Patt
mesh_terms: D001577:Benzophenones; D006801:Humans; D016268:Internal Fixators; D007659:Ketones; D010865:Pilot Projects; D011092:Polyethylene Glycols; D011108:Polymers; D019736:Prostheses and Implants; D013123:Spinal Fusion / Q000379:methods*; D013125:Spinal Neoplasms / Q000532:radiotherapy*; D013131:Spine / Q000601:surgery*
chemical_list: D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols