On the mechanical behaviour of PEEK and HA cranial implants under impact loading

Abstract

The human head can be subjected to numerous impact loadings such as those produced by a fall or during sport activities. These accidents can result in skull fracture and in some complex cases, part of the skull may need to be replaced by a biomedical implant. Even when the skull is not damaged, such accidents can result in brain swelling treated by decompressive craniectomy. Usually, after recovery, the part of the skull that has been removed is replaced by a prosthesis. In such situations, a computational tool able to analyse the choice of prosthesis material depending on the patient's specific activity has the potential to be extremely useful for clinicians. The work proposed here focusses on the development and use of a numerical model for the analysis of cranial implants under impact conditions. In particular, two main biomaterials commonly employed for this kind of prosthesis are polyether-ether-ketone (PEEK) and macroporous hydroxyapatite (HA). In order to study the suitability of these implants, a finite element head model comprising scalp, skull, cerebral falx, cerebrospinal fluid and brain tissues, with a cranial implant replacing part of the skull has been developed from magnetic resonance imaging data. The human tissues and these two biocompatible materials have been independently studied and their constitutive models are provided here. A computational model of the human head under impact loading is then implemented and validated, and a numerical comparison of the mechanical impact response of PEEK and HA implants is presented. This comparison was carried out in terms of the effectiveness of both implants in ensuring structural integrity and preventing traumatic brain injury. The results obtained in this work highlight the need to take into account environmental mechanical considerations to select the optimal implant depending on the specific patient: whereas HA implants present attractive biointegration properties, PEEK implant can potentially be a much more appropriate choice in a demanding mechanical life style. Finally, a novel methodology is proposed to assess the need for further clinical evaluation in case of impact with both implants over a large range of impact conditions.

Novel 3D Hybrid Nanofiber Aerogels Coupled with BMP‐2 Peptides for Cranial Bone Regeneration

“…Perhaps, the concentration of the released Sr 2+ and Cu 2+ from the hybrid aerogels is below the therapeutic levels necessary for bridging such large bone defects. Another explanation could be the mismatch between the compression strength of the 3D nanofiber aerogels (0.5 to 2.5 MPa) and that of the native cranial bone (8000 MPa), [36] as mechanotransduction can play an important role in the healing of mechanosensitive bone tissue. [37] However, the 3D hybrid aerogels do promote the sprouting of new blood vessels in the regenerated fibrous connective and bone tissue in comparison to the defect only group (Figure 10).…”

Mechanical Properties Optimization of Poly-Ether-Ether-Ketone via Fused Deposition Modeling

“…Poly-ether-ether-ketone (PEEK) has received widespread attention due to the good mechanical properties, biocompatibility and elastic modulus closing to human bones, and is considered one of the most promising bone repair materials [ 1 , 2 ]. As demands of PEEK increase, additive manufacturing (AM) is starting to be used in the forming process of PEEK components.…”

Cognition based bTBI mechanistic criteria; a tool for preventive and therapeutic innovations

“…For this purpose, the validated FEHM recently developed by Garcia-Gonzalez et al . 17 was refined and human MRI Diffusion Tensor Imaging (DTI) information was incorporated to estimate the regional fibre orientation of white matter (Figs 3A and S4). The human head model was subjected in silico to four blast injury scenarios: frontal and lateral blast incident orientations at two blast intensities each: i) detonation of 2.3 kg charge of C-4 at a 2.3 m standoff distance (360 kPa magnitude blast) and ii) detonation of 3 kg charge of Octol explosive at 2–3 m standoff distance (1.3 MPa magnitude blast).…”

“…The pre-processing of the head model without the axonal tract information follows the previous work of Garcia-Gonzalez et al . 17 . Briefly, geometrical information was obtained from high resolution anatomical T1 and T2-weighted MRI images of Subject ID: 100307 of the Human Connectome Project 77 .…”