Specific problems arise during the delayed reconstruction of posttraumatic craniofacial defects and deformations, which have to be treated for both aesthetic and functional reasons (Evans et al. 1985; Manson et al. 1986; Merten and Luhr 1994; Kuttenberger et al. 1996; Sullivan and Manson 1998).

•An anatomically, functionally, and aesthetically correct reconstruction of the craniofacial structures protects the brain from damage and late injuries and avoids secondary neurological disturbances, infections, and stigmatizing disconfiguration.

In our own series, secondary reconstruction was necessary with the following indications:

•Defects not reconstructed during primary treatment, 35%

•Contour irregularities due to bone resorption, 55%

•Contour irregularities due to infection, 10%

14.1  Reconstruction Materials

and Techniques

Craniofacial bone defects can be reconstructed using different techniques and implant materials. The choice of the implant material depends on the size and shape of the defect to be reconstructed and on the conditions of the recipient area.

•Reconstruction with autogenous bone/cartilage (calvarium/rib/iliac crest)

•Reconstruction with xenogenous bone/cartilage (bovine/equine bone/lyophilized cartilage)

•Reconstruction with alloplastic bone substitutes (carbonate-calcium-phosphate bone cement, PEEK)

•Reconstruction with titanium-mesh systems

•Reconstruction with preformed titanium implants

•CAD/CAM implants from different materials (titanium/medical raisins)

14.1.1  Autogenous Grafts

14.1.1.1  Split Calvarial Grafts

When reconstructing defects in the cranial skeleton, most authors primarily favor autogenous bone, mainly split calvarial grafts (Lee et al. 1995).

In large defects, autogenous split calvarial grafts provide better results due to their contour stability compared with autogenous rib, iliac crest and deep freezed autogenous calvarial bone grafts (Frohberg and Deathevage 1991; Dufresne et al. 1992; Salyer 1989, 1992; Mathog 1992; Hardt et al. 1994; Lee et al. 1995; Prein 1998; Sullivan and Manson 1998).

Calvarial grafts are usually taken from an area neigh­ boring the defect and separated into tabula externa and interna. Because of their convexity, the grafts (tabula interna) are easily adapted to the frontocranial defect (Dempf et al. 1998).

After integrating the split calvarial grafts, small remaining gaps are filled with bone dust or bone chips previously collected during the craniotomy.

• Calvarial grafts and titanium mesh

An aesthetically efficient symmetrical contour can be achieved by additional titanium mesh coverage in large defects treated with split calvarial grafts. Conspicuous irregularities caused by resorption can simultaneously be avoided. The mesh may be supported by a bone graft to prevent it from sinking in the immediate postoperative phase (Hardt et al. 1994; Kuttenberger et al. 1996).

Irregularities in the areas between the grafts and between graft and genuine calvarium can be avoided by additionally covering the contact zones with micromesh strips (Hardt et al. 1994) (Figs. 14.1–14.4).

14.1.1.2  Cartilage Grafts

Cartilage grafts can be added, if major contour irregularities of the whole forehead have to be corrected and if graft resorption must be reduced to a minimum to maintain good aesthetic long-term results (Probst 1971, 1973, 1986).

or bovine bone (Kübler et al. 1998; Tsukagoshi et al. 1998; Eufinger et al. 1999), and lyophilized allogenous cartilage (Sailer 1983; Sailer and Kolb 1994), which have been used in cranio-maxillo-facial reconstruction for many years.

The complicated processing of these tissues, however, has prevented their widespread use so far.

•Reconstruction of craniofacial bone defects with autogenous or allogenic bone transplants may lead to minor irregularities caused by bone resorption.

Calvarial grafts are usually incorporated as living tissue with reparative and osteoconductive capability (Lee et al. 1995).

This capacity has also been demonstrated for autolysed antigen-extracted xenogenous bone, such as equine

Although autogenous calvarial grafts provide good results, there are nevertheless several limitations:

•Autogenous bone grafts are associated with additional donor-site morbidity

Fig. 14.1  Reconstruction of an extensive fronto-glabellar defect with split calvarial graft and contouring with a titanium mesh. (a) Residual extensive defect of the forehead 6 months after primary treatment of a severe gunshot injury. (b) Three-dimensional CT scan depicting the frontal bone defect. (c) Cranioplasty using autogenous split calvarial grafts from the parietal region. (d)

Residual slight contour irregulatities in the frontal area were corrected with a titanium mesh (0.6 mm). The space underneath the mesh was filled with an additional bone graft (arrow). (e) Patient 3 years postoperative with symmetrical and smooth contour of the forehead.(f )Postoperative3DCTscandemonstratingmicroplates, bonegrafts, and dynamic mesh in place

Fig. 14.2  Skull reconstruction after osteoclastic craniotomy. (a) Preoperative depression of the parasagittal parietal skull contour. (b) Secondary bony reconstruction with split calvarial

grafts from the left temporo-parietal region. (c) Completed reconstruction and fixation of the bone grafts with miniplates

Fig. 14.3  Secondary reconstruction of the forehead with split calvarial grafts and titanium mesh. (a) Preoperative situation showing extensive forehead defect after osteoclastic intervention. (b) Intraoperative forehead reconstruction with split calva-

rial grafts from the parietal region. The donor region is covered with a titanium mesh (0.3 mm). (c) Postoperative result showing smooth and symmetrical contour of the forehead

•Adequate form and sufficient quantity are not always available

•Unpredictable resorption may occur

As a consequence, various alternative substitutes are used in craniofacial surgery, which do not require a second donor site and guarantee an unlimited availability of noninfectious material (Holmes 1990).

Requirements for alloplastic bone substitutes

•Mechanical long-term stability

•Biointegration/biocompatibility

•Moulding ability

•Contour stability

•Favorable cost-factor

Fig. 14.4  Secondary forehead reconstruction. (a) Extensive frontoparietal bone defect. (b) Reconstruction with biparietal split skull grafts. The residual donor defect was closed with an additional iliac

bone graft. Contouring with micro-titanium mesh strips. (c) Postoperative result after 6 months. (d) Postoperative result after 10 years, demonstrating stability of the reconstruction

14.1.3.1  Synthetic Calcium Phosphates

These substitutes vary greatly in their properties (osteoconductivity, biocompatibility, mechanical stability), as well as having diverse forms of preparation. They are divided into two groups, granulate and cements, which are mixed during surgery and applied as a paste (Holmes 1990; Costantino et al. 1993; Costantino­ and Friedman 1994).

• Hydroxyapatite granulate

Good results were achieved using hydroxyapatite for cranial reconstruction (Costatino et al. 1991, 1992; Nakayima et al. 1995; Burstein et al. 1997, 1999; Pistner et al. 1998; Byrd et al. 1993; Wiltfang et al.

2004). Pistner et al. (1998) pointed out that a dry operating field is mandatory when using hydroxyapatite. This is certainly not always possible in craniofacial surgery.

• Bone cements

In general, the modern carbonate-calcium-phosphate bone cements exhibit good biocompatibility, which is based upon their osteoconductive properties, unhindered biodegradation and osteoclastic resorption with osseous replacement (Constantz et al. 1995; Franken­ burg et al. 1998; Smart et al. 2005).

In addition, there is a direct bone apposition on the surface of the bone cement without connective tissue interposition even in the early postoperative phase