The influence of metal artifacts on navigation and the reduction of artifacts by the use of polyether-ether-ketone

Abstract

Registration is a crucial step in navigation assisted surgery. When performing anatomical pair-point registration, there are several potential sources of error, including inadequate data acquisition, improper segmentation, and distortion resulting from metal artifacts. The aim of this study was to evaluate the influence of metal artifacts on the precision of Iso-C 3D and fluoroscopy-based navigation, and to assess any changes in precision from the use of a newly developed Schanz screw composed of polyether-ether-ketone (PEEK OPTIMA Õ ). A T-shaped test specimen was manufactured from synthetic bone material. It was then scanned with a Siremobil Õ Iso-C 3D while different types of implant were present in the specimen. Five Iso-C 3D scans were acquired: one with a steel Schanz screw in the specimen, one with a titanium screw, one with a PEEK screw, one with a 5-hole plate, and one with no screw or plate present. The registration was analyzed by ''reverse verification'' with a pointer in a purpose-built, manipulable 3D holder. All experiments were then repeated using fluoroscopy-based navigation.Increasing presence of metal in the scan area resulted in an increase in mean error (0.55 mm with the steel Schanz screw, 0.7 mm with the 5-hole plate). Artifacts resulting from the titanium Schanz screw were less than those caused by the stainless steel Schanz screw. While this study demonstrates that metallic artifacts do have an influence on the precision of Iso-C 3D navigation, such artifacts were not found to be a factor when performing fluoroscopy-based navigation.

Comparative Analysis of Optoelectronic Accuracy in the Laboratory Setting Versus Clinical Operative Environment: A Systematic Review

“…In addition to distance between camera source and fiducial arrays, Citak et al 70 , 80 performed an investigation to determine the maximum acceptable distance between fixed reference arrays and dynamic “mobile” arrays within the operative field. The results demonstrated a mean registration error of 0.04 mm (0.04-0.05 mm) up to a distance of 200 mm from the patient reference array.…”

“…The initial registration and intra-operative working accuracy is significantly reduced with localization of arrays greater than 200 mm from the patient reference point. 70 , 80 Moreover, the magnitude of errors secondary to array obstructions differ based on active versus passive markers and distance between arrays. 35 When comparing 2 active Vicon fiducial arrays versus distance, targeting errors increased from 0.47 mm to 1.2 mm, with corresponding stepwise decreases from 5 cm to 0 cm between arrays.…”

Limitations and pitfalls of 3-D fluoroscopic navigation in orthopaedic trauma surgery

“…Both techniques, navigation and 3-D imaging itself, do have specific limitations, consequently the combination of both systems might combine these limitations. As reported by some studies in recent publications, limitations of 3-D c-arm navigation have been found in various applications [3,4,6,8].…”