Computer-assisted pedicle screw fixation. A feasibility study.
METHODS
We evaluated a computer-assisted surgical tool for inserting pedicle screws.


OBJECTIVE
This study reviewed the feasibility, usefulness, and accuracy of the proposed tool.


BACKGROUND
Reviews documented neurovascular damage caused by screw misplacement. Currently, screw hole position is assessed by radiologic means and curette palpation.


METHODS
Three sheep vertebrae and one artificial object were reconstructed three-dimensionally from computed tomography scan slices. At surgery, the surgeon's movements were displayed relative to the three-dimensional vertebrae on a computer screen. The tool was used to detect pedicles and to verify the position of drilled holes. In our laboratory, we calculated the system's accuracy by taking measurements on the artificial object.


RESULTS
All pedicles were identified with the computer. Five of the six drilled hole positions were correctly represented. An accuracy of 4.5 mm +/- 1.1 mm RMS (root of the mean squared) and 1.6 degrees +/- 1.2 degrees were calculated.


CONCLUSIONS
Results suggested the proposed system could be useful for pedicle detection and assessing the intravertebral location of a drilled hole. The proposed system could be used for many different orthopedic procedures where structures are hidden from the surgeon's view.
Amiot
L P
LP
Département d'orthopédie, Hôpital Ste-Justine, Université de Montréal, Canada.
Labelle
H
H
DeGuise
J A
JA
Sati
M
M
Brodeur
P
P
Rivard
C H
CH
D000818:Animals; D001863:Bone Screws; D003196:Computer Graphics; D005240:Feasibility Studies; D007091:Image Processing, Computer-Assisted; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D012756:Sheep; D012984:Software; D013131:Spine / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed