15.1  Overall Objective

The reconstruction of craniofacial defects is a challen­ ging task even for the experienced surgeon. For an optimal solution the techniques and principles that have been described in the chapters before must be adapted to the individual situation. The challenges result from the patient’s individual situation, the preoperative planning efforts, from technical aspects as well as from the reconstructive means available. While the use of autografts has been the most widely recommended method, it does have its drawbacks, including long operation times, donor site morbidity, limited donor bone supply, as well as different anatomic and structural problems. The availability of autogenous bone grafts resembling the form of the skull is limited. Therefore, there is a need for alternative materials with adequate mechanical properties and biocompatibility (Blake et al. 1990; Eufinger et al. 1995; Eufinger and Wehmöller 1998, 2002; Klongnoi et al. 2006; Wiltfang et al. 2002, 2003; Schiller et al. 2004; Thorwarth et al. 2005; von Wilmowsky et al. 2008).

15.2  Patient-Related Conditions

The size of the defect, delayed, or inadequate debridement of the wound, delayed, or inadequate treatment of the patient or the relatively high risk of infections are the typical causes for complications in craniofacial injuries. In addition to primary or secondary treatment

1Contributed by Peter Kessler, Maastricht Universitair Medisch Centrum, Maastricht (NL), Clinic of Cranio - Maxillofacial Surgery, The Netherlands

attempts, the morbidity of the patient and the risk of the planned reconstructive procedure may result in severe complications. Concerning the patient situation, the following questions have to be answered before an attempt for reconstruction is made:

•Size and location of the defect

•General health status

•Neurological status

•Patient’s wish/compliance

•Treatment plan

•Technical aspects

15.2.1  Size and Location of the Defect

The size of the defect plays an important role in the determination of the reconstructive procedure. Poukens et al. (2008) have developed a classification as a basis for the intended reconstruction. When designing skull implants, the sometimes complicated geometry of the defects is important to consider. Defects crossing the midline, or defects including the orbital rim or roof of the orbit, pose a greater challenge for design and manufacturing than a simple one-sided parietal bone defect. Apart from the size and extent of the defect, these anatomical factors ought to be included when classifying skull defects. The proposed classification (Table 15.1) is, therefore, based on three factors that determine the complexity of the reconstruction:

•Size of defect in cm2

•Defects crossing the midline of the skull

•Involvement of the orbital rim/roof

The size of skull defects is important for obvious reasons­ – the larger the defect, the larger the span of curvature that has to be reconstructed. The implant should