Chiari I malformation associated with atlanto-axial dislocation: focussing on the anterior cervico-medullary compression
- 178 Downloads
Background. Chiari I malformation with atlantoaxial dislocation may cause both posterior and anterior cervicomedullary compression. We studied the clinicoradiological features and surgical outcome in patients having Chiari I malformation with atlantoaxial dislocation.
Method. Thirty-nine patients with Chiari I malformation with atlanto-axial dislocation underwent preoperative and follow-up neurological status assessment. In Chiari I malformation with reducible atlanto-axial dislocation (n = 11), a direct posterior stabilization was done. In Chiari I malformation with irreducible atlanto-axial dislocation (n = 28), a single stage transoral decompression with posterior stabilization and/or posterior decompression and duraplasty were done in 18 patients. In 10 patients, only posterior decompression and/or posterior stabilization was performed. Seven among the latter patients subsequently deteriorated and required transoral decompression. Comparison of mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization versus the posterior procedure alone was done using T-test and proportional significance also calculated.
Findings. Patients with Chiari I malformation with atlanto-axial dislocation have a high incidence of long tract signs and sphincteric disturbances with a decrease in the mean foramen magnum diameter. The mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization were significantly better than those patients who underwent the posterior procedure alone. The latter patients also showed significant clinical improvement following transoral decompression. In the presence of Chiari I malformation with reducible atlanto-axial dislocation, reduction and stabilization of atlanto-axial dislocation resulted in neurological improvement. The follow up neurological status scores of these patients improved after surgical intervention even in the presence of poor preoperative grades.
Conclusions. Patients with Chiari I malformation should be investigated for the presence of atlanto-axial dislocation. In case atlantoaxial dislocation coexists, priority must be given to relieving anterior cervicomedullary compression.
Unable to display preview. Download preview PDF.
- Arora, P, Behari, S, Banerji, D, Chhabra, DK, Jain, VK 2004Chiari I malformation: factors affecting outcomeNeurol India52484486Google Scholar
- Brooks, AL, Jenkins, EB 1978Atlantoaxial arthrodesis by the wedge compression methodJ Bone Joint Surg (Am)60279284Google Scholar
- Crockard, HA, Calder, L, Ransford, AO 1990One-stage transoral decompression and posterior fixation in rheumatoid atlanto-axial subluxationJ Bone Joint Surg (Br)72682685Google Scholar
- Jain, VK, Behari, S 1997Posterior occipitoaxial fusion for atlantoaxial dislocation associated with occipitalized atlasWilkins, RRengachary, S eds. Neurosurgical Operative atlasAmerican Association of Neurological SurgeonsIllinois249256Google Scholar
- Klekamp, J, Samii, M 1993Introduction of a score system for the clinical evaluation of patients with spinal processActa Neurochir (Wien)123221223Google Scholar
- Locke, GR, Gardner, JI, Van Epps, EF 1966Atlas-dens interval (ADI) in children: a survey based on 200 normal cervical spineAm J Roentgenol97135140Google Scholar
- Malcolm, GP, Ransford, AO, Crockard, HA 1994Treatment of non-rheumatoid occipitocervical instability. Internal fixation with the Hartshill-Ransford loopJ Bone Joint Surg (Br)76357366Google Scholar
- Ransford, AO, Crockard, HA, Pozo, JL, Thomas, NP, Nelson, IW 1986Craniocervical instability treated by contoured loop fixationJ Bone Joint Surg (Br)68173177Google Scholar
- Salunke, P, Behari, S, Sharma, MS, Jaiswal, AS, Jain, VK 2006Pediatric congenital atlantoaxial dislocation: differences between the irreducible and reducible varietiesJ Neurosurg (2 Suppl Pediatrics)104115122Google Scholar
- White, AA,III, Panjabi, MM 1978The clinical biomechanics of the occipitoatlantoaxial complexOrthop Clin N Am9867878Google Scholar