Design of cervical pedicle locator and three-dimensional location of cervical pedicle.
METHODS
To develop a high-accuracy, easy-manipulated, and low-cost cervical pedicle three-dimensional locator for guiding cervical pedicle screw placement.


OBJECTIVE
To improve the safety of cervical pedicle screw insertion, simplify its manipulation, and offer safety guarantees in clinical application.


BACKGROUND
Because of the complicacy of the anatomic structure of cervical pedicle, clinical application of cervical pedicle screw remained hard to popularize. And recent advances on cervical pedicle location did not simplify the manipulation of procedure significantly. Without aid of locator, distance and angle errors were difficult to control. So far, the only instrument for the location of pedicle "computer-assisted image-guided surgical system" is too expensive for clinical use. Furthermore, it has not yet been documented on location instrument for insertion of cervical pedicle screws.


METHODS
The high-accuracy three-dimensional locator, made of stainless steel was designed to aid cervical pedicle nail placement. The cadavers were inserted nails under guidance of the locator that has been input the corresponding parameters collected from CT images. Results were evaluated by CT scans.


RESULTS
A total of 90 nails were inserted into cervical pedicles, 90% of which were found right in the pedicles; 10% had pedicle cortex breaches. Parallel offset error of the locator in cross-sectional and lateral CT image that was 0.56 +/- 0.70 and 1.04 +/- 0.99; angular offset error was 1.69 +/- 2.41 and 6.54 +/- 7.08.


CONCLUSIONS
Three-dimensional locator of cervical pedicle and its localization technique achieved good results for individuated screws insertion into cervical pedicles, having such advantages as easy manipulation, high accuracy, and low cost. The system presented safety guarantee to the application and advanced the prevalence of pedicle techniques. Its principium and design were demonstrated feasible.
Mao
Guang-Ping
GP
Department of Orthopedics, Nanjing University Jinling Hospital, Nanjing City, P. R. China. Mao-GP@sohu.com
Zhao
Jian-Ning
JN
Wang
Yu-Rong
YR
Li
Jie-Shou
JS
Chen
Yue-Xian
YX
Wu
Su-Jia
SJ
Bao
Ni-Rong
NR
D001863:Bone Screws; D002574:Cervical Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery*; D004867:Equipment Design; D005240:Feasibility Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods; D016268:Internal Fixators; D007431:Intraoperative Complications / Q000209:etiology / Q000517:prevention & control; D015641:Radiography, Interventional / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D014057:Tomography, X-Ray Computed