Anterior Retropharyangeal Titanium Cage Distraction Of The Atlantoaxial Joints For Reducing Basilar Invagination: A First Report In The Literature
S Patkar
Keywords
anterior atlanto-axial joint fixation, atlanto-axial dislocation, atlanto-axial joint distraction, basilar invagination, chiari malformation syringomyelia
Citation
S Patkar. Anterior Retropharyangeal Titanium Cage Distraction Of The Atlantoaxial Joints For Reducing Basilar Invagination: A First Report In The Literature. The Internet Journal of Spine Surgery. 2015 Volume 10 Number 1.
DOI: 10.5580/IJSS.32469
Abstract
An adult male presented with spasticity in all 4 limbs and difficulty in walking of recent onset. No trauma was reported. He had no other systemic symptoms. Lateral X-ray and computerised axial tomography CT scan revealed atlanto-axial dislocation with basilar invagination. We describe the surgical procedure and outcome of this case.
Case Report
Clinical summary
An adult male presented with spasticity in all 4 limbs and difficulty in walking of recent onset. No trauma was reported. He had no other systemic symptoms.
Lateral X-ray and computerised axial tomography CT scan revealed atlanto-axial dislocation with basilar invagination (Figure 1 and Figure 2).
Figure 1
Figure 2
Procedure: The atlanto-axial joints were exposed under general anaesthesia in supine position by an anterior extrapharyangeal approach. Joint cartilage was curetted and endplates were abraded. Special wedge titanium cages of 5 mm in height (Jayon Surgical Co India) were filled with bone substitute and impacted into the joints on both sides. Additionally, the lateral mass of the atlas (C1) was fixed to the body of the axis ( C2) using titanium plates and screws (Figure 3).
Figure 3
Postoperative CT scan and X-ray showed reduction of the basilar invagination and fixation of the atlantoaxial dislocation. (Figure 4, Figure 5, and Figure 6).
Figure 4
Figure 5
Figure 6
Discussion:
Basilar invagination can be reduced by spacer insertion into the atlantoaxial joint1. Recently this technique has been recommended for syrinomyelia and Chiari malformation2. However, posterior surgery has inherent difficulties such as risk vertebral artery injury, paravertebral venous plexus hemorrhage and necessity of sacrificing the C2 ganglion in most cases3.
The anterior extrapharyangeal approach offers a safe corridor to achieve all the aims of the posterior operation without all the problems of the posterior approach4. The surgery is performed in supine position with extension resulting in reduction of the atlanto-axial dislocation in most cases.
The anterior approach is using through muscle planes unlike the posterior approach which disrupts the suboccipital and C2 spinous process muscle attachments which are so very essential for craniovertebral stability6.
A wedge shaped cage distracts the joint and reduces the atlantoaxial dislocation. The large bone mass of the atlas and body of axis allow ample opportunity for easy, safe and rigid fixation of the atlanto-axial joint6.
This is the first report of a clinical case of basilar invagination reduced and fixed by anterior surgery.