Custom cranioplasty using stereolithography and acrylic

Numerous methods of cranioplasty have been described, Customisation and pre fabrication have been reported to reduce operating time and improve cosmesi s. An original technique for the manufacture of customised cranioplastic im plants has been developed and tested in 30 patients. Thirty patients requiring cranioplasties were selected. Data acquired from computed tomography (CT) were used to manufacture exact plastic replicas (b iomodels) of craniotomy defects and master cranioplastic implants using the rapid prototyping technology of stereolithography (SL). The three-dimensio nal (3D) imaging techniques of mirroring and interpolation were used to ext rapolate on existing anatomy to design the master implants. The master impl ants were hand finished to fit the defect in the corresponding cranial biom odel exactly and were then used to create a cavity mould. The mould was use d to cast thermally polymerised custom acrylic implants. The surgeons reported that the customised implants reduced operating time, afforded excellent cosmesis and were cost effective. The patients reported that the opportunity to see the biomodel and implant preoperatively improve d their understanding of the procedure. Two complications were noted, one i nfection and one implant required significant trimming. The simultaneous manufacture of the master implant (male) and biomodel (fem ale) components from SL allowed custom accurate implants to be manufactured . Disadvantages identified were the time required for computer manipulation s of the CT data (up to 2 h), difficulty in assessing the accuracy of the c omputer generated master as a 3D rendering, the potential for SL parts to w arp, manufacturing time (minimum days) and the cost of approximately $1300 US per case ($1000 for the SL biomodel and $300 for the acrylic casting). ( C) 2000 The British Association of Plastic Surgeons.