Page 182 - IJB-9-1

International Journal of Bioprinting PEEK skull implant in cranioplasty

1. Background 2. Case presentation
Cranioplasty is mainly used for skull defects caused by In June 2022, a 33-year-old male was admitted to the
a previous operation or injury, so as to reconstruct the Department of Neurosurgery of the Affiliated Hospital of
continuity of the skull and restore the normal anatomical Southwest Medical University due to skin dimpling of the
[1]
structure . Titanium mesh is a commonly used material left eyebrow arch. After admission, the 3D reconstruction
for cranioplasty, generally performed without precise of head computed tomography (CT) was performed
[2]
anatomical markers . However, radiographic examinations (Figure 1A–C), the defect area includes the left frontal
2
are inevitably affected by artifacts in patients with titanium bone and supraorbital, with an area of about 80 cm . Other
implants. Implant exposure and deformation as a result of laboratory examinations and tests showed no obvious
external force are known complications of titanium mesh abnormalities.
cranioplasty and are usually managed by implant removal Fifteen years ago, this patient underwent a left forehead
[3]
or exchange .
tumor resection and titanium mesh cranioplasty due to the
Polyether ether ketone (PEEK) is a potentially left frontal osteoma. The resection range includes the left
suitable biomaterial for cranioplasty due to its prominent supraorbital and part of the frontal bone, and a cranioplasty
characteristics, such as good biocompatibility, low was performed using titanium mesh. In recent months, the
radiographic artifacts, and elastic modulus similar to patient felt that the left forehead became flat and collapsed,
cortical bones . Previous clinical case reports have resulting in an asymmetric appearance of left and right
[4]
demonstrated the successful application of the patient- sides of the forehead. This caused a severe negative impact
specific subtractive manufacturing PEEK skull implant on his life, so he came to the hospital for treatment.
with good precise anatomic, esthetic reconstruction The specifications of PEEK implants suitable for
that resulted in fewer postoperative complications [5,6] . this patient are discussed. A 3D model was used in the
Nonetheless, the inherent drawback associated with computer to reconstruct the skull’s appearance after using
the subtractive manufacturing of PEEK skull implants the PEEK implant (Figure 1D–F). We increased the overall
was their processing methods that hindered the repair curvature of the PEEK implant and reduced the thickness
of complicated skull defects. Subtractive manufacturing of the edge of the PEEK implant during the designing
PEEK is expensive because a great deal of materials process (Figure 1F). On the one hand, the increase of
could be wasted. Additionally, this technique sometimes curvature can prevent the compression of the brain tissue
requires piecing multiple implants together due to caused by the implant, and make the appearance of the
the complex anatomy; situations that require piecing left and right sides of the forehead more symmetrical,
multiple implants include cranioplasty for large-scale meeting the patient’s esthetic requirements. On the other
cranial defects and repair of complex anatomical hand, the thickness of the cranial margins of the patients
structures .
[7]
was not uniform. The skull was relatively thin in the center
Additive manufacturing (AM) is a process of joining of the skull defect and relatively thick in the periphery, the
materials to make objects from three-dimensional (3D) thin PEEK implant edge ensures a tighter bond between
model data using a layer-by-layer method, which is the implant and the skull, making it easier to fix the
[8]
opposed to subtractive manufacturing methodologies . implant to the skull. Using this embedded PEEK implant
To fabricate low-cost PEEK orthopedic implants with for cranioplasty is visually and functionally superior to
[12]
large and complex anatomical structures, additive covered cranioplasty .
manufacturing techniques were used to meet patient- The flow chart of the FFF printing of the PEEK skull
specific demands. AM custom-made PEEK implants have implant is shown in Figure 2A. Surgical-grade PEEK
been used in the reconstruction of chest wall defects and filament with a diameter of 1.75 mm was bought from
mandibular defects repair in recent studies because of the Shaanxi Jugao-AM Medical Technology Co., Ltd. (China)
advantages in the aspects of cost and individual skeletal for FFF. The as-designed skull implant model was imported
reconstruction [9-11] . However, studies on AM custom-made into slicer software for slicing and then loaded into the FFF
PEEK skull prostheses are limited.
machine (Xi’an Jiaotong University) (Figure 2B). The actual
Here, we present a case of a patient who underwent stress condition of a PEEK skull implant in the clinical
titanium mesh exchange with the fused filament fabrication application should be considered during data processing to
(FFF)-fabricated PEEK implant. The feasibility of using an ensure that the anisotropy will not affect the service life of
FFF-fabricated PEEK implant to repair skull defects with the implant. The concentric circle path filling method was
complex geometries was demonstrated in this study. chosen to manufacture the PEEK skull implant. The FFF

Volume 9 Issue 1 (2023)olume 9 Issue 1 (2023)
V 174 https://doi.org/10.18063/ijb.v9i1.634