Planning of skull reconstruction based on a statistical shape model combined with geometric morphometrics

Marc Anton Fuessinger, Steffen Schwarz, Carl Peter Cornelius, Marc Christian Metzger, Edward Ellis, Florian Probst, Wiebke Semper-Hogg, Mathieu Gass, Stefan Schlager

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


Purpose: Virtual reconstruction of large cranial defects is still a challenging task. The current reconstruction procedures depend on the surgeon’s experience and skills in planning the reconstruction based on mirroring and manual adaptation. The aim of this study is to propose and evaluate a computer-based approach employing a statistical shape model (SSM) of the cranial vault. Methods: An SSM was created based on 131 CT scans of pathologically unaffected adult crania. After segmentation, the resulting surface mesh of one patient was established as template and subsequently registered to the entire sample. Using the registered surface meshes, an SSM was generated capturing the shape variability of the cranial vault. The knowledge about this shape variation in healthy patients was used to estimate the missing parts. The accuracy of the reconstruction was evaluated by using 31 CT scans not included in the SSM. Both unilateral and bilateral bony defects were created on each skull. The reconstruction was performed using the current gold standard of mirroring the intact to the affected side, and the result was compared to the outcome of our proposed SSM-driven method. The accuracy of the reconstruction was determined by calculating the distances to the corresponding parts on the intact skull. Results: While unilateral defects could be reconstructed with both methods, the reconstruction of bilateral defects was, for obvious reasons, only possible employing the SSM-based method. Comparing all groups, the analysis shows a significantly higher precision of the SSM group, with a mean error of 0.47 mm compared to the mirroring group which exhibited a mean error of 1.13 mm. Reconstructions of bilateral defects yielded only slightly higher estimation errors than those of unilateral defects. Conclusion: The presented computer-based approach using SSM is a precise and simple tool in the field of computer-assisted surgery. It helps to reconstruct large-size defects of the skull considering the natural asymmetry of the cranium and is not limited to unilateral defects.

Original languageEnglish (US)
Pages (from-to)519-529
Number of pages11
JournalInternational Journal of Computer Assisted Radiology and Surgery
Issue number4
StatePublished - Apr 1 2018


  • 3D planning
  • Computer-assisted surgery (CAS)
  • Statistical shape model (SSM)
  • Virtual defect reconstruction

ASJC Scopus subject areas

  • Health Informatics
  • Radiology Nuclear Medicine and imaging
  • Computer Vision and Pattern Recognition
  • Surgery
  • Biomedical Engineering
  • Computer Science Applications
  • Computer Graphics and Computer-Aided Design


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