[Experimental study of cervical pedicle screw locator system].
OBJECTIVE
To develop a high-accuracy, better-safety and low-cost cervical pedicle locator system for guiding cervical pedicle screw placement.


METHODS
Cervical pedicle screw locator system was made of stainless steel. Ten cervical specimens from voluntary donation were divided into two groups according to compatibility design: control group in which 60 screws were planted into C(2-7) by free hand; and experimental group in which 60 screws were planted into C(2-7) under the guidance of three-dimensional locator system. The condition of screw insertion was observed and the accuracy was evaluated by the integrity of pedicle walls.


RESULTS
In the control group, 32 screws (53.33%) were placed inside the pedicles and 28 (46.67%) were outside; 9 screws (15.00%) led to nerve root injury, 5 screws (8.33%) caused vertebral artery injury and no spinal cord injury occurred; and the qualification ratio of screw insertion was 76.67% (excellent 32, fair 14, poor 14). While in the experimental group, 54 screws (90.00%) were placed inside the pedicles and 6 (10.00%) were outside; 1 screw (1.67%) caused vertebral artery injury and no nerve root injury and spinal cord injury occurred; and the qualification ratio of screw insertion was 98.33% (excellent 54, fair 5, poor 1). There was significant difference between the two groups (P < 0.05).


CONCLUSIONS
Cervical pedicle screw locator system has the advantages of easy manipulation, high accuracy of screw placement and low cost. With further study, it can be applied to the clinical.
Department of Orthopaedics, Ningbo No.6 Hospital, Ningbo Zhejiang, PR China. caojin111@163.com
Jin
J
Cao
Rongming
R
Xu
Long
L
Zhou
Zhaoping
Z
Zhong
Weihu
W
Ma
Ming
M
Li
D001863:Bone Screws; D002574:Cervical Vertebrae / Q000601:surgery*; D004867:Equipment Design; D006801:Humans; D016268:Internal Fixators