Page 108 - Clinical relevance of current materials for cranial implants

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Chapter 5
Computer-assisted design (CAD) and computer-assisted manufacturing (CAM) has been used to make titanium, hydroxyapatite and PMMA implants. Prefabrication of a patient-specific implant (PSI) reduces operation time and produces superb cosmetic results30. Recently, computer-assisted 3-dimensional modeling of poly (ether ether ketone) (PEEK), another polymer, has been successfully introduced for cranial reconstruction36,37. It is a strong and highly thermoplastic material. It resembles titanium in its perfect intraoperative fitting and its resistance to aggressive sterilization procedures (heat and ionizing radiation). On the contrary, the elasticity and energy- absorbing properties of PEEK match closer to bone than the mechanical properties of titanium. And unlike titanium, it is a radiolucent and a non-magnetic material, facilitating postoperative imaging25,31,37-39. PEEK has a few disadvantages: it has no bioactive potential and the costs related to the manufacturing of a PSI are high39.
The aim of this study is to evaluate patient- and surgery-related characteristics and risk factors that predispose patients to an increased risk of complications after PEEK cranioplasty.
MATERIAL AND METHODS
Study design and patient population
This retrospective study included 38 consecutive patients who underwent 40 PEEK cranioplasties from 2011 to 2014 in the Academic Medical Center Amsterdam (24 cranioplasties) and the St. Elisabeth Hospital Tilburg (16 cranioplasties). Both centers used identical protocols and procedures for skull reconstruction by means of PSI. The current series included all patients who underwent PEEK cranioplasty. No patients were excluded. The study protocol was approved by the local medical-ethical review board (local protocol no. L87.2015; METC no. Nw 2015-38).