Clinical accuracy of fluoroscopic computer-assisted pedicle screw fixation: a CT analysis.
METHODS
Observational cohort study with computerized tomography (CT) analysis of in vivo pedicle screw placement.


OBJECTIVE
To evaluate the clinical accuracy of computer-assisted fluoroscopy for the placement of thoracic and lumbosacral (LS) pedicle screws.


BACKGROUND
Computer-assisted fluoroscopy is an adjunct for the placement of pedicle screws.


METHODS
Postoperative CT of 360 titanium pedicle screws (281 LS [L1-S1]; 79 thoracic [T2-T12]) were independently assessed. All screws were placed using the FluoroNav system (Medtronic Surgical Navigation Technologies, Louisville, CO). The relative position of the screw to the pedicle was graded as follows: A = completely in; B = <2 mm breach; C = 2-4 mm breach; and D = >4 mm breach. If an osseous breach occurred, the direction of the breach was further classified.


RESULTS
Eight-five percent of screws were completely contained within the pedicle. Fifty-five-pedicle breaches (25 medial; 30 lateral) occurred. Pedicle breaches were graded B in 13.1% (47 breaches), C in 1.9% (7), and D in 0.3% (1) of screws. Pedicle breach was significantly higher in the thoracic compared to the LS spine, 31.6% (25/79) and 10.6% (30/281), respectively (P < 0.0001). In the thoracic spine, 72% of pedicle breaches were lateral. In 49% of breaches, the screw diameter was larger than the pedicle diameter. None of the pedicle breaches were associated with neurologic or other clinical sequelae.


CONCLUSIONS
The clinical pedicle breach rate in this study is comparable to those reported using conventional techniques with or without fluoroscopic assistance. FluoroNav appears to be a safe adjunct for the placement of thoracic and LS pedicle screws.
Rampersaud
Y Raja
YR
Division of Orthopaedic, University of Toronto, Toronto, Ontario, Canada. raja.rampersaud@uhn.on.ca
Pik
Justin H T
JH
Salonen
David
D
Farooq
Samina
S
D001863:Bone Screws / Q000009:adverse effects; D015331:Cohort Studies; D005471:Fluoroscopy; D006801:Humans; D013122:Spinal Diseases / Q000601:surgery; D013124:Spinal Injuries / Q000601:surgery; D013131:Spine / Q000000981:diagnostic imaging* / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000592:standards; D014057:Tomography, X-Ray Computed