Transarticular screw fixation for atlantoaxial instability - modified Magerl's technique in 38 patients.

Raj Bahadur,Tarun Goyal,Saravdeep S Dhatt,Sujit K Tripathy

doi:10.1186/1749-799x-5-87

Abstract

BackgroundSymptomatic atlantoaxial instability needs stabilization of the atlantoaxial joint. Among the various techniques described in literature for the fixation of atlantoaxial joint, Magerl's technique of transarticular screw fixation remains the gold standard. Traditionally this technique combines placement of transarticular screws and posterior wiring construct. The aim of this study is to evaluate clinical and radiological outcomes in subjects of atlantoaxial instability who were operated using transarticular screws and iliac crest bone graft, without the use of sublaminar wiring (a modification of Magerl's technique).MethodsWe evaluated retrospectively 38 subjects with atlantoaxial instability who were operated at our institute using transarticular screw fixation. The subjects were followed up for pain, fusion rates, neurological status and radiographic outcomes. Final outcome was graded both subjectively and objectively, using the scoring system given by Grob et al.ResultsInstability in 34 subjects was secondary to trauma, in 3 due to rheumatoid arthritis and 1 had tuberculosis. Neurological deficit was present in 17 subjects. Most common presenting symptom was neck pain, present in 35 of the 38 subjects.Postoperatively residual neck and occipital pain was present in 8 subjects. Neurological deficit persisted in only 7 subjects. Vertebral artery injury was seen in 3 subjects. None of these subjects had any sign of neurological deficit or vertebral insufficiency. Three cases had nonunion. At the latest follow up, subjectively, 24 subjects had good result, 6 had fair and 8 had bad result. On objective grading, 24 had good result, 11 had fair and 3 had bad result. The mean follow up duration was 41 months.ConclusionsTransarticular screw fixation is an excellent technique for fusion of the atlantoaxial complex. It provides highest fusion rates, and is particularly important in subjects at risk for nonunion. Omitting the posterior wiring construct that has been used along with the bone graft in the traditional Magerl' s technique achieves equally good fusion rates and is an important modification, thereby avoiding the complications of sublaminar wire passage.

Highlights

Symptomatic atlantoaxial instability needs stabilization of the atlantoaxial joint
The distribution of subjects by etiology is given in table 1
Neurological deficit was present in 17 subjects (44.7%)

Summary

Introduction

Among the various techniques described in literature for the fixation of atlantoaxial joint, Magerl’s technique of transarticular screw fixation remains the gold standard. Posterior C1-C2 fusion using transarticular screw (TAS), introduced by Magerl et al in 1979 [1] is the gold standard for atlantoaxial arthrodesis. It has the advantage of a more rigid fixation with higher rates of fusion, avoiding need for postoperative halo, no placement of implant in the spinal canal, and possibility of its use in anomalies of odontoid process or the posterior arch [2,3,4,5,6,7]. It has been found that there may be no important contribution of the wires in holding the graft for fusion, and comparable fusion rates have been achieved in these studies [4,13,14]

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