Acute atlanto-axial post-operative subluxation following posterior C1/2 fusion

Abstract

Two cases referred with acute post-operative C1/2 subluxation following posterior fusion are reported. Both cases had initial treatment for atlanto-axial instability with posterior cable (Brooks and interspinous) and graft techniques, and placed immediately in a Philadelphia collar. One case was found to have subluxed immediately post-operatively when failing to breathe following reversal of anaesthetic agents, and despite immediate realignment and reoperation was left with a significant quadriparesis. The other patient was noted to have subluxed on routine X-ray on day 4, and had no neurological deficit before or after reoperation. Risk factors for this dangerous complication are discussed and the techniques of C1/2 posterior fusion and stabilization are reviewed in detail. Surgeons performing atlanto-axial stabilization procedures should be familiar with and have expertize in the complete range of techniques described and choose the one most appropriate for the patient’s individual requirements.

Introduction

Atlanto-axial instability has been treated with posterior wire and bone constructs for over 60 years,[1], [2], [3] and variations on these techniques remain in common use today. Although there have been concerns regarding the rigidity of these stabilization methods when used alone, and an external orthosis is usually also recommended in the post-operative period, reports of complications relating to this lack of rigidity have related to the failure to develop solid bony arthrodesis and the development of late instability.[4], [5], [6]

There have not been previous reports of acute subluxation in the immediate post-operative period after posterior stabilization and fusion procedures. Two cases of this dangerous complication are reported and discussed.