Image-Guided Internal Fixation of an Oblique Sagittal Split Fracture of C1 Lateral Mass with Motion Preservation: A Technical Report.

James G Malcolm,Lee A Tan,Andrew K Johnson

doi:10.7759/cureus.1496

James G Malcolm, Lee A Tan + Show 1 more

Open Access

https://doi.org/10.7759/cureus.1496

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Abstract

A sagittal split fracture of the C1 lateral mass is an unstable subtype of C1 fractures and has a high propensity for developing late deformities and pain with nonoperative management. A primary internal fixation of this type of fracture has been recently described with good clinical outcomes and preservation of motion. We present a modified technique of primary internal fixation using an obliquely inserted C1 lag screw with imaging guidance. We successfully treated a 55-year-old woman with a unilateral C1 oblique sagittal split fracture who failed nonoperative management. Technical nuances are discussed with a review of pertinent literature.

Highlights

Unilateral C1 lateral mass sagittal split fractures are unstable subtypes of C1 fractures that can often lead to a cock-robin deformity, where the head is rotated toward and tilted away from the affected side with significant pain and restricted motion [1]
Primary internal fixation using bilateral C1 lateral mass screws connected by a rod has been shown to yield a good clinical outcome with motion preservation [2]
We describe a modified C1 primary fixation technique using imaging guidance to insert an obliquely oriented C1 lateral mass screw for the reduction and fixation of a C1 lateral mass split fracture

Summary

Introduction

Unilateral C1 lateral mass sagittal split fractures are unstable subtypes of C1 fractures that can often lead to a cock-robin deformity, where the head is rotated toward and tilted away from the affected side with significant pain and restricted motion [1]. Preoperative images demonstrating the C1 oblique right split fracture (arrows): (A) an axial computed tomography (CT) scan showing an oblique fracture line through the lateral mass and the posterior arch; (B) a coronal CT scan showing a 5 mm overhang of C1 over C2; (C) an open-mouth odontoid x-ray after two weeks of rigid orthosis showing the settling of the C1 right lateral mass. Using O-arm imaging guidance (Medtronics, Dublin, Republic of Ireland), a screw trajectory was planned in a posterolateral to anteromedial direction, almost perpendicular to the fracture line This trajectory entered the lateral mass posterior to the vertebral artery and the transverse foramen passing across the fracture line into the anterior arch (Figures 2A and 2B). A follow-up computed tomography (CT) scan at six months after the second stage with (A) axial and (B) sagittal views demonstrating a stable C1 screw-rod construct with evidence of bone growth across the fracture

Discussion

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