Vertical mobile and reducible atlantoaxial dislocation. Clinical article.
ABSTRACT The authors' experience with treatment of 8 patients with "vertical mobile and reducible" atlantoaxial dislocation is reviewed. The probable pathogenesis, radiological and clinical features, and management issues in such cases are discussed.
Between January 2006 and March 2008, 8 patients who presented with vertical mobile and reducible atlantoaxial dislocations were treated at the Department of Neurosurgery at King Edward Memorial Hospital in Mumbai, India. The vertical atlantoaxial dislocation/basilar invagination reduced completely on extension of the neck, with no need of any cervical traction. According to the extent of superior migration of the odontoid process, and measurements based on the vertical atlantoaxial instability index, the dislocation was graded as mild, moderate, or severe. All patients were treated using the C-1 lateral mass and C-2 pars plate and screw method of fixation.
The study group was composed of 5 male and 3 female patients (mean age 24 years, age range 8-54 years). All patients presented with the physical features of short neck, torticollis, pain in the nape of the neck, and varying degrees of quadriparesis. In 6 patients there was a history of trauma prior to the onset of major neurological symptoms. The dislocation was mild in 3 cases, moderate in 1, and severe in 4. All patients had clinical neurological improvement following surgery. The follow-up duration ranged from 4 to 30 months (mean 18 months).
Vertical mobile and reducible atlantoaxial dislocation is a discrete clinical entity. Abnormal inclination and incompetence of the facet joint appears to be the primary causative factor that resulted in vertical dislocation or basilar invagination. Posterior fixation in the reduced dislocation position forms the basis of treatment.
Article: The importance of platybasia and the palatine line in patient selection for endonasal surgery of the craniocervical junction: a radiographic study of 12 patients.[show abstract] [hide abstract]
ABSTRACT: Ventral decompressive surgery of the craniocervical junction is performed to manage a variety of conditions, including basilar invagination, which can be associated with platybasia. We have noted that the anatomic changes of platybasia could affect the height of the odontoid over a line drawn along the nasal cavity floor, the palatine line (PL). This anatomic change may influence the use of nasal endoscopic surgery for patients with platybasia who also have basilar invagination. We investigated whether the height of the craniocervical junction is elevated over the PL in patients with and without platybasia. We conducted a retrospective review of consecutive craniovertebral junction surgical cases during a 14-month period. During that time we treated 12 patients, including 4 with platybasia and 8 without. The average age was 50 years (range, 18-64 years). Preoperative and postoperative radiographic images were evaluated and charts reviewed. The mean height of the odontoid over the PL without platybasia was 3.5 mm (range, 0-19.0 mm). In those with platybasia, it was 15.5 mm (range, 7-26.0 mm; P=.021). There was a statistically significant increase in the height of the clival tip and C1 ring in patient with platybasia as well. Platybasia is associated with an increase in the odontoid and craniocervical junction over the PL. This increase in height has implications for endoscopic approach selection in patients with platybasia. Platybasia patients with basilar invagination may be better suited to a transnasal approach.World Neurosurgery 76(1-2):183-8; discussion 74-8. · 0.68 Impact Factor