Report of a New Passive, Optical Surgical Navigation

System for Endoscopic Sinus Surgery

Martin J. Citardi, M.D.

Saint Louis University

Department of Otolaryngology

Computer-Aided Sinus Surgery

Anatomic complexityLimitations of endoscopic visualizationSurgical navigation systems

SAVANT

New CAS platformCbyon (Palo Alto, CA)Optical tracking systemWindows NT platformReport of initial FDA

trial

Methods

Prospective trial (FDA protocol)1 mm axial CT transferred to workstation

via networkVisual estimates of registration accuracySurgeon’s questionnaires

SAVANT

Pre-release software version (0.8-0.9)Headset reference frameSemiautomatic registrationPassive (wireless) instruments

Semiautomatic Registration

Headset at time of CT scan and OR

Registration to points on headset

SAVANT Instrumentation

Results

17 patients enrolledIndication: chronic rhinosinusitisFailure to achieve acceptable registration

in 1 instanceSurgery canceled in 1 instance (asthma

exacerbation)15 patients completed protocol

Results

Registration accuracy estimates at 4 points in surgical volume

Distribution of estimates:

0-2 mm. 38 (63.3%)

2-4 mm. 14 (23.3%)

4-6 mm. 3 (5.0%)

>6 mm. 5 (8.3%)

Subjective Evaluation

Relatively easy set-up, especially for a developmental system

Good user interfaceExcellent monitorExcellent technical support

Representative Images

Headset Issues

Modified Anatomark headset (designed for co-registration of MR/CT scans)

DRF designEar piece calibrationFully automatic

registration anticipated

Advantages

Even semiautomatic registration rapidPassive (wireless) trackingExcellent user interfaceAutomatic registration in development

Disadvantages

Headset design issuesSemiautomatic registration

Note: Technical solutions are on the horizon…

Summary

Preliminary report of a new CAS system for sinus surgery

Promising technological platformSystem limitations identified; technical

solutions in early implementation phaseAdditional reports forthcoming…