Page 24 - Clinical relevance of current materials for cranial implants

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Chapter 1
Patient-specific allogenic reconstruction is a typical example of advances in the medical technology. It demonstrates improvement of patient-relevant outcomes. With these technologies, it is possible to study and evaluate the corresponding clinical findings. In Chapter 4, a PMMA (CMW-3) cranioplasty is described, which had been inserted in a patients’ cranium 15 years ago, but had to be removed because of neurological complaints, most likely due to fracture of the implant. This case is evaluated by means of gel permeation chromatography (GPC), a micro-CT, finite element analysis (FEA) and flexural strength measurements.
The high infection and resorption rates have led to a search for superior synthetic materials for cranioplasties. In Chapter 5, a two-center retrospective study is described, including 38 patients who underwent 40 patient-specific cranioplasties of PEEK to detect possible complications and results.
Part IV: Towards a new approach
To improve the precise outlining of the cranioplasty and the aesthetic outcomes and to shorten operation time, different and relatively new intra-operative techniques may be used.
In Chapter 6, three cases are presented who underwent a cranioplasty of PEEK. The resection was guided with resection and control templates. Outcomes were compared with the original patient-specific planning and with 3D comparisons for form.
Squamous cell carcinoma with bony invasion into the scalp is a rarely described phenomenon in the literature. The optimal treatment strategy is still under debate. In Chapter 7 we present a patient with this anomaly. A novel comprehensive, one-stage surgical treatment is demonstrated and discussed.
Part V: Towards the ideal material
The properties of current materials for cranioplasties are important to understand and to progress to development of new materials. Part V of this thesis comprises two in vitro studies: Do different PMMA-based materials include different amounts of residual monomers? does sterilization has an effect on the mechanical properties of PMMA- based materials?