Page 363 - IJB-10-4

International Journal of Bioprinting 3D-printed PEEK in cranioplasty

1. Introduction demonstrated the safety, effectiveness, and aesthetics of
AM-fabricated PEEK skull implants in clinical use. 14
Poly-ether-ether-ketone (PEEK) is a semicrystalline
performance engineering thermoplastic with good physical In this study, we investigated the practicability, safety,
performance (e.g., excellent thermal stability, chemical and aesthetics of 3D-printed PEEK implants for cranial
stability, radiation resistance, mechanical processing, repair compared to autologous bone and titanium
friction resistant, and low shrinkage) and excellent mesh implants.
1-4
biocompatibility. By virtue of these desirable attributes,
PEEK is positioned as an alternative to metal implants and 2. Methods
1-5
the preferred material for plastic and trauma surgery. 2.1. Patient recruitment
Previous studies have reported that PEEK skull implants We recruited patients who underwent cranioplasty
processed by mechanical polishing have better aesthetics between January 2021 and March 2023. Informed
and induce complications at a rate comparable to other consent was obtained from the patients and/or their legal
types of implants (e.g., autologous bones and titanium representatives. This study was conducted in compliance
6,7
mesh). Additive manufacturing (AM) refers to a specific with the Declaration of Helsinki. This study was approved
method of generating physical objects by combining (KY2021133) by the Ethics and Research Committees of
the materials layer-wise from a three-dimensional (3D) the Affiliated Hospital, Southwest Medical University.
virtual model, thereby enhancing the precision of forming
complex structures and minimizing raw material wastage The electronic medical records of these patients were
as compared to conventional methods. In contrast to reviewed to collect demographic information, such as
8
subtractive manufacturing (SM), AM has the advantages age, sex, neurological function score, radiographic data
of flexible design, low material costs, controllable (e.g., computed tomography [CT] images), duration of
structural properties, and the ability to optimize local surgery, postoperative hospitalization, and postoperative
mechanical properties according to the specific application complications. We subsequently divided the patients into
(e.g., bio-integration). 9-14 three groups depending on the materials used during
cranioplasty: fused filament fabrication (FFF)-printed
Cranioplasty is a neurosurgical procedure to repair PEEK, autologous bone, and titanium mesh.
skull defects caused by severe central nervous system
diseases, such as tumors, intracranial hemorrhage (ICH), 2.2. Production of implants
and acute ischemic stroke (AIS). Cranioplasty is a surgical The manufacturing process of PEEK implants is displayed
procedure that involves (i) separating the skin flap from in Figure 1. For patients who opted for PEEK implants,
the scar tissue and dura mater, (ii) isolating the atrophied the clinical doctors and material experts would initially
temporal muscles, (iii) identifying the bone edge of the construct the 3D anatomy of the patient’s skull and design
affected skull area, (iv) fixing the skull implant, and (v) the specifications of the PEEK implants. Medical-grade
restore the external tissues. 6-23 Cranioplasty can restore filaments with a diameter of 1.75 mm were selected to
anatomical structures that proximate physiological develop the PEEK implants (Jugao AM, Shaanxi, China).
conditions and protect brain tissues, as well as the The designed skull implant model was processed with
aesthetics of a patient. 14-16 Although cranioplasty is an microscopic software, and the relevant data were input
established neurosurgical procedure, the selection of an into an FFF system (Xi’an Jiaotong University, Shaanxi,
optimal implant material remains a challenge for material China). For the preparation of the PEEK skull implant,
scientists and clinicians. Several implant materials, the concentric circle path-filling method was used.
7
including titanium mesh and autologous bone, have been After inputting the parameters, such as layer thickness
abundantly utilized over the past decades, but not without (0.2 mm), nozzle diameter (0.4 mm), bed temperature
their respective limitations and clinical indications. (20°C), chamber temperature (20°C), nozzle temperature
Likewise, 3D-printed PEEK implants feature bone-like (430°C), and printing speed (40 mm/s) into the FFF
characteristics and personalized designs that have been printer (printer model: Surgeon Pro), the PEEK skull
successfully applied for chest wall reconstruction, denture implants were automatically printed layer-wise (Figure 1a
manufacture, scapula prosthesis, and mandibular defect and b). The FFF-printed PEEK prosthetic skull schematic
reconstruction. 17-20 However, there is a lack of research on diagram is displayed in Figure 1c. We subsequently
AM-fabricated PEEK skull implants. Thus far, only a few scanned the printed PEEK implant using a 3D scanner
preclinical studies have confirmed the advantages of AM- (XTOM-MATRIX, XTOP 3D, Guangdong, China) and
fabricated PEEK skull implants, including high accuracy, virtually integrated the PEEK implant into the skull
adaptiveness to complex anatomical structures, and good model for further analysis. We would grind (reshape)
mechanical properties. 21,22 Our previous case report has the printed PEEK implants and repeat the analysis until

Volume 10 Issue 4 (2024) 355 doi: 10.36922/ijb.2583