Impact of fiducial arrangement and registration sequence on target accuracy using a phantom frameless stereotactic navigation model

Timothy R. Smith*, Divakar S. Mithal, James A. Stadler, Camelia Asgarian, Kenji Muro, Joshua M. Rosenow

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Modern frameless stereotactic techniques utilize scalp fiducial markers for registration. Anecdotal reports from surgeons indicate a variety of methods for improving accuracy using different fiducial arrangements and registration sequences. The few published studies on registration accuracy do not provide a simple and systematic method for determining target accuracy. Nine different arrangements of ten fiducial markers were attached to a model. Ten separate markers were designated as targets for evaluation of registration accuracy. We systematically registered each of the arrangements over multiple trials, in one of four sequences, and then measured the targets. The target coordinates were compared against the established target values, and a root-mean-square deviation (RMSD) was derived. A systematic multivariate analysis determined the effects of different variables on the RMSD. We found no correlation between the "Registration Accuracy" provided by Medtronic (Medtronic Navigation, Louisville, CO, USA) and our RMSD representing targeting accuracy (R = 0.008). RMSD did vary for different fiducial arrangements. We found no significant difference between the various sequences of fiducial arrangement. Thus, regardless of fiducial arrangement, registration sequence has no impact on accuracy. Fiducial arrangements distributed optimally across the skull, however, allowed for significantly improved accuracy. Further studies are required to determine which different arrangements of fiducials are relevant for specific procedures.

Original languageEnglish (US)
Pages (from-to)1976-1980
Number of pages5
JournalJournal of Clinical Neuroscience
Issue number11
StatePublished - Nov 1 2014


  • Accuracy
  • Brain mapping
  • Frameless stereotaxy
  • Functional neurosurgery
  • Image-guided neurosurgery
  • Neuronavigation
  • Stereotactic surgery

ASJC Scopus subject areas

  • Surgery
  • Neurology
  • Clinical Neurology
  • Physiology (medical)


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