Chinese Journal Of Clinical Anatomy ›› 2016, Vol. 34 ›› Issue (1): 53-58.doi: 10.13418/j.issn.1001-165x.2016.01.015

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Radiographic measurement and the screw placement strategies of axis quadricortical pedicle screw

ZHOU Xin 1,2,  MA Xiang-yang 2,  YANG Jin-cheng 2,  QIU feng 2,  XIAO yao-sheng 2,  HU hai-sheng 2   

  1. 1.Postgraduate Institute,Second Military Medical University,Shanghai 200433,China; 2. Department of Orthopedic Surgery,General Hospital of Guangzhou Military Command,Guangzhou 510010,China
  • Received:2015-08-25 Online:2016-01-25 Published:2016-01-28

Abstract:

Objective To study the feasibility of screw placement strategies and the technique of axis quadricortical pedicle screw.  Methods 49 males and 43 females with normal cervical spine were included. At the C2 pedicle level of MRI images, we marked the tangent of pedicle medial wall which was parallel with central axis of C2 pedicle, and measured the distance between the tangent and spinal cord and the distance between the tangent and dura mater. At the same time, the tangent of C2 spinal canal medial wall which was parallel with sagittal axis of C2 was marked too, also we checked the distance between the tangent and spinal cord and the distance between the tangent and dura mater. Spinal cord diameter, spinal canal diameter and other associated parameters were recorded too. Result No statistical difference occurred between same sex.The mean distance between C2 pedicle medial wall and spinal cord was (male 9.05 mm, female 8.57 mm); The mean distance between C2 pedicle medial wall and dura mater was (male 5.04 mm, female 4.76 mm); The mean distance between the C2 spinal canal medial wall and spinal cord was (male 7.14 mm, female 6.70 mm); The mean distance between the C2 spinal canal medial wall and dura mater was (male 3.28 mm, female 3.28 mm).     Conclusion    At the C2 level, the space between the C2 spinal canal medial wall and dura mater was safe for C2 quadricortical pedicle screw;However, there were individual differences among patients.Therefore, different screw placement strategies should be applied based on different situations.

Key words:  Axis pedicle, Quadricortical pedicle screw, Tricortical pedicle screw, MRI