Page 200 - Clinical relevance of current materials for cranial implants

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Chapter 10
Choosing an optimal treatment strategy for reconstruction of a skull defect after ablative tumor surgery presents another interesting dilemma for additional research. In these less acute situations, there is more time to plan preoperatively. Various techniques and timing of surgery have been described in literature for both soft tissue management and bony reconstruction. There is no standard treatment strategy for clinical decision-making in these low-volume high-complex cases. Patient and tumor treatment factors, such as (neo)adjuvant radiotherapy, prior treatments, medical history and comorbidity in frequently old and frail patients, may further hamper decision-making in reconstructing cranial defects. This is why an innovative technique was used in chapter 7 by applying a virtual pre-surgical 3D planning with the use of a patient-specific cranioplasty of PEEK. This technique aims for optimized control of the resection margin and less intra-operative dilemma’s. Wound dehiscence is still a feared complication in these cases. Since bone invasion is unpredictable and varying, an individual approach for calvarian reconstruction in every oncological case will be necessary. Adequate clinical reporting of larger case-series may produce guidelines for this patient group in the near future. Meanwhile, the different clinical, surgical and patient-specific aspects should be taken into account.
Towards a new material
Based on the current knowledge, an ideal material for cranioplasties should:
. be sterile and have anti-bacterial properties
. have osteo-inductive and/or osteo-conductive properties
. exert similar protective characteristics as human bone
. demonstrate no toxicity
. be easy to polish
. be easy to use intraoperatively
. have stable and consistent mechanical properties
. be easy for computer assisted additive manufacturing
. have low costs
In Chapter 8 different PMMA materials were investigated. This chapter showed that each of these materials, have their own release pattern of residual monomers. C&B MFH, a PMMA-based material designed for 3D printing, proved to have the lowest amount of residual monomers in total. The most residual monomers were released in the first hour for all materials investigated. If this material would be used for cranioplasties in the future, it is recommended to leave the cranioplasty in water at 37oC for at least 60 minutes to enable the residual monomers to leach out the material to reduce toxicity.