gms | German Medical Science

56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
3èmes journées françaises de Neurochirurgie (SFNC)

Deutsche Gesellschaft für Neurochirurgie e. V.
Société Française de Neurochirurgie

07. bis 11.05.2005, Strasbourg

Fused Deposition Modelling and CAD generated preoperative implant fabrication for cranioplasty

Fused Deposition Modeling und CAD generierte, preoperative Implantatherstellung für die Kranioplastie

Meeting Abstract

  • J. Leppert - Department of Neurosurgery, University Hospital Schleswig-Holstein, Campus Lübeck
  • D. Foethke - Department of Neurosurgery, University Hospital Schleswig-Holstein, Campus Lübeck
  • U. Knopp - Department of Neurosurgery, University Hospital Schleswig-Holstein, Campus Lübeck
  • H. Ssenyonjo - Department of Neurosurgery, University Hospital Schleswig-Holstein, Campus Lübeck
  • S. Gottschalk - Department of Neuroradiology, University Hospital Schleswig-Holstein, Campus Lübeck
  • K. Kramer - Department of Computer-Aided Engeneering, University of Applied Sciences, Lübeck
  • J. Wulf - Department of Anatomy, University of Lübeck
  • corresponding author A. Giese - Department of Neurosurgery, University Hospital Schleswig-Holstein, Campus Lübeck

Deutsche Gesellschaft für Neurochirurgie. Société Française de Neurochirurgie. 56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3èmes journées françaises de Neurochirurgie (SFNC). Strasbourg, 07.-11.05.2005. Düsseldorf, Köln: German Medical Science; 2005. DocP222

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2005/05dgnc0490.shtml

Veröffentlicht: 4. Mai 2005

© 2005 Leppert et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective

Trauma, calvarian tumors and defects following decompressive surgery are the main reasons for large cranial defects. Indications for reconstruction of these defects are cosmetic and/or protection against mechanical impact. The intraoperative free-hand modelling of skull implants, in particular with large defects, turns out to be technically difficult and operating times increase. We report a technique of Rapid Prototyping (RP) for custom reconstruction of cranial defects using Fused Deposition Modeling (FDM) which is based on routine radiographic diagnostics.

Methods

In a cadaver specimen, a craniectomy was performed and a model of the defect was built using Fused Deposition Modeling. Implant design was based on the preoperative imaging data using a mirror image of the contralateral side modified by “free hand” CAD. The CAD data of the mold were transferred to a .STL-file format to generate rapid prototyping models. Different acrylic implants were built using the mold. In addition alternative prefabricated implants were built, based on a wax matrix free-hand formed on the FDM model. The wax matrix was then imprinted in a silicone form and the wax was removed. Subsequently a conventional free-hand formed implant was modelled directly into the cranial defect. The different implants were radiographically imaged and the reconstructions were compared to the preoperative images.

Results

Free-hand intraoperative direct modeling of PMMA implants into the cranial defect showed the highest inter-individual variation of the implant fit and cosmetic result. The intraoperative modeling times were more than four times longer than implantation of prefabricated implants and ranged from 26-44 minutes. Both prefabricated implants based on free-hand wax models or CAD designed Fused Deposition Modeling produced implants showed excellent cosmetic results and very low inter-individual variation. However, wax modeling into an artificially produced defect was very labor intensive and required a three day processing time.

Conclusions

Our results demonstrate that FDM generated anatomical models and negative molds of the defects provide a rapid and highly accurate method of custom implants of skull defect reconstructions, which is based on routine CT data and commercially available hardware and CAD software components. It is a cost-effective alternative to industrially produced implants. The implant fabrication can be performed preoperatively by the operating surgeon.