Freehand C2 Laminar Screw Placement: Technical Note and Operative Video.

William Clifton,Jose O Garcia,Aaron Damon,Kingsley Abode-Iyamah,Mark Pichelmann

doi:10.7759/cureus.5549

Abstract

The placement of C2 laminar screws is a safe and useful method of axis fixation. The freehand method of screw placement was originally described by Wright et al., and requires detailed knowledge of the C2 posterior element anatomy, relationship to vital neurovascular structures, and technical acumen. The current evidence, surgical anatomy and technical details of screw insertion are investigated and highlighted in this manuscript and surgical video.

Highlights

Fixation of the upper cervical spine has been performed with various techniques ranging from wiring methods to polyaxial screw placement [1, 2]
This technique is advantageous in that it lessens the risk of vertebral artery injury while providing a biomechanically stable means of fixation [4]
C2 laminar screw placement is generally reserved as a salvage mechanism in cases of anatomic variations in the V3 vertebral artery segment, as well as iatrogenic or traumatic disruptions of the C2 pedicle [5]

Summary

Introduction

Fixation of the upper cervical spine has been performed with various techniques ranging from wiring methods to polyaxial screw placement [1, 2]. An alternate technique of C2 fixation is the laminar screw, which is placed from the contralateral spinous process/laminar junction [3]. The interface of the C1-2 facet joints is offset anteriorly from the subaxial cervical facets, placing the majority of the downward axial load of the head onto the C2 posterior elements Because of this anatomic characteristic, C2 typically possesses a larger pedicle and laminar diameter than the subaxial vertebrae [7]. Screw starting points are planned visually by identifying the superior and inferior borders of the spinolaminar junction in order to assess locations of screw placement in such a way that will allow the screws to be placed in a contralateral trajectory without interfering with each other’s path. A lateral connector may be be used in order to properly connect the rod, this is avoided to mitigate the potential bio-mechanical disadvantages of lateral connection [2,10]

Discussion

Conclusions

Disclosures

Wright NM

Wang MY