Custom made cranioplasty prostheses in porous hydroxy-apatite using 3D design techniques: 7 years experience in 25 patients.

BACKGROUND

None of the materials currently used to reconstruct skull defects is fully satisfactory. Their biological and physical properties are very different to those of natural bone. Solid state, high porosity hydroxy-apatite (HA) seems to be a good support for bone regeneration within the prostheses, enabling integration of the heterologous material with low post-implant infective risk.

MATERIALS AND METHODS

A model of the cranium of each patient was made in epoxy resin by stereolithography. The prosthesis was built on this model using a ceramic sintering process. In each case, an exact copy of the missing bone flap was obtained (curvature, dimensions, margins, irregularities and thickness). The porosity obtained is the same as that of the spongy bone of the skull with interconnected macropores (>150 microm) to promote osteoblast migration into the prosthetic core. In The Neurosurgery Division of Cesena, 26 cranioplasty prostheses have been implanted with this technique in 7 years (from 1998 to 2004). No particular criteria were pre-established, but the main indications for use of ceramic prostheses were complex and/or extended (surface >25 cm(2)) post-surgery craniolacuna and/or previous unsuccessful procedures due to rejection, infection or bone flap reabsorption.

RESULTS

Twenty-five patients were included in this study. A clinical check-up and 3D CT (mean follow-up 30 months, range 12-79) always showed an excellent aesthetic result. No cases of infection, rejection or spontaneous prosthesis fragmentation were found. The surgical procedure was simpler and shorter than for other described procedures.

CONCLUSIONS

Bioceramic porous hydroxy-apatite prosthesis have been demonstrated as a valid alternative to traditional cranioplasty techniques both aesthetically and in terms of absence of infections/rejections. Principal limitations for the use of HA prostheses are the need for stereolithography process, the poor malleability of the material and the high cost.