Page 16 - ARNM-2-2

Advances in Radiotherapy
& Nuclear Medicine CFR-PEEK: A systematic review

Table 3. Complication rates of CFR‑PEEK screws
Complications Number of studies Total number of patients Total number of events Incidence rate (%) 95% CI
CSF leak 2 399 8 2.01 0.95 – 3.07
Hardware failure 7 592 19 (4 postoperative, 15 intraoperative) 3.2 2.42 – 3.98
Screw loosening 7 603 21 (3 postoperative) 3.48 3.03 – 3.93
Wound issue 7 614 51 (8 postoperative) 8.31 6.23 – 10.39
Other complications 4 478 28 5.86 3.98 – 7.74
Notes: Wound issues encompass surgical site infections, atrophic wound healing disorder, and wound breakdown. Others include epidural hematoma,
incidental durotomy, pulmonary embolism, new neurologic deficit, pneumonia/pleural effusion, urinary tract infection, screw contact with aortic wall,
and cement-related complications.
Abbreviations: CI: Confidence interval; CFR-PEEK: Carbon fiber-reinforced polyetheretherketone; CSF: Cerebrospinal fluid.

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Table 4. Comparison of CFR‑PEEK and titanium overall reduced dose distal to the implant. Proton therapy
demands greater energy photons to penetrate the dense
Titanium CFR‑PEEK titanium implant to deliver proper dose to distal tissue
Cost Lower Higher compared to CFR-PEEK. There is also greater uncertainty
Imaging artifact (MRI/CT) Higher Lower in dosing when artifact is present on CT and MRI.
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Durability Similar Similar Furthermore, Poel et al. demonstrated that CFR-PEEK
Complication rates Similar Similar has a gamma passing rate closest to the native spine,
Abbreviations: CT: Computed tomography; MRI: Magnetic resonance measuring 83.5% and 83.3%, respectively, compared to
imaging; CFR-PEEK: Carbon fiber-reinforced polyetheretherketone. 81.3% for titanium and 67.1% for a hybrid CFR-PEEK
titanium implant. Shen et al. showed that CFR-PEEK
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A primary benefit of CFR-PEEK instrumentation vertebral body replacements (VBRs, corpectomy cage)
is decreased imaging artifact (CT and MRI), which allowed for higher-quality surveillance imaging, especially
may facilitate more precise therapy and more accurate in visualizing the epidural space, which facilitated more
follow-up, minimizing the toxicity and complications effective postoperative adjuvant radiotherapy, with less need
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associated with other oncologic treatments. 20-22 Figure 2 to perform additional procedures for radiation dosimetry.
demonstrates the improved soft tissue visualization for a Ringel et al. compared the computed tomography
patient instrumented with CFR-PEEK and subsequently Hounsfield units (CT-HU) of CFR-PEEK and titanium
treated with adjuvant SBRT for local tumor control. hardware, finding they were ~500 and >2000, respectively.
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CFR-PEEK has shown a total volume of artifact reduction This difference in CT-HU supports radiation therapy
by over 90% compared to titanium, from 390 cc to 33.9 cc, planning for adjuvant treatments, delivery of radiation
which led to a reduced time to delineate severe artifact on dose due to less absorption, and follow-up imaging to track
CT from 172 to 43.7 min. Depauw et al. reported data postoperative response. The use of CFR-PEEK hardware
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supporting minimal to no use of metal artifact reduction could reduce the need for CT myelogram to obtain accurate
on CT for CFR-PEEK hardware compared to titanium visualization of the spine, epidural space, and surrounding
alloy as well as described the impact of instrumentation organs. Planning can be done using MRI, without CT
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on adjuvant radiotherapy. With better postoperative myelogram. Optimizing these factors and other elements of
visualization of the fused segments, spinal cord, and other oncologic care may improve hardware durability, promote
major anatomical landmarks, CFR-PEEK allows physicians fusion, and improve oncologic response.
to plan, deliver, and if needed, reevaluate the postoperative Most of the included papers in this review focused on
radiotherapy plans more effectively. the safety and efficacy of CFR-PEEK implants, with some
CFR-PEEK instrumentation has also been shown to minor focus on comparison to titanium instrumentation,
decrease the materialistic effects on radiation dosing. and therefore, the long-term complications were one of the
Contrary to most metal implants, CFR-PEEK allows only major common variables reported between studies.
radiation to pass through during treatment and potentially The work included focused more on mechanical/physical
decreases radiation scatter and the need for large field complications of CFR-PEEK and less on other aspects of
radiation. Conversely, photon therapy (conventional long-term care. Future work should highlight long-term
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radiotherapy) in patients with titanium hardware results patient-reported outcomes and other wellness variables as
in 10.72% increased backscatter proximal to the implant a secondary measure of the successful use of CFR-PEEK in
compared to CFR-PEEK (2.01% at 6 megavolts) and an spine oncology.

Volume 2 Issue 2 (2024) 8 doi: 10.36922/arnm.3130