[Ventral decompression techniques in patients with traumatic and non-traumatic atlanto-axial dislocations]

Compression of the caudal medulla oblongata and ventral portions of the spinal cord is the most dangerous complication of atlanto-axial dislocation (AAD).

The study objective was to improve surgical management of patients with ventral compression of the spinal cord in the setting of AAD of various genesis.

We analyzed treatment outcomes in 250 patients with C1 and C2 injuries and diseases for the period between 2002 and 2016. Persistent ventral compression of the neural structures in the setting of AAD was detected in 34 (13.6%) patients. Anterior or posterior dislocation was in 21 patients, vertical dislocation occurred in 7 patients, and mixed (anterior and vertical) occurred in 6 cases. The causes of AAD included odontoid fractures (21 patients, 61.8%), Jefferson fractures (6 patients, 17.6%), atlas transverse ligament rupture (1 patient, 2.9%), rheumatoid arthritis (4 patients, 11.8%), and nonspecific spondylitis (2 patients, 5.9%).

All dislocations were divided into Halo-tractable and Halo-intractable ones. In 24 cases, ventral decompression was achieved due to Halo reposition. Additional resection of a compressing substrate was performed through the submandibular approach in 4 patients, through the transoral approach in 5 patients, and through the transnasal approach in 1 case. In the postoperative period, complications in the form of pharyngeal edema developed in 1 patient after transoral decompression. In the other cases, there were no postoperative complications. All patients had improvement in their condition in the form of regression of a neurological deficit.

Halo reposition is a technique eliminating, completely or partially, ventral compression in certain traumatic and non-traumatic dislocations. The choice of a surgical corridor should be performed after preliminary Halo correction. If the nasopalatine line runs in the odontoid neck projection, the submandibular approach may be used in the case of a Halo-tractable dislocation, and the endonasal approach may be used in the case of a Halo-intractable dislocation.