The surgical treatment of Chiari malformation association with atlantoaxial dislocation.

Five cases of Chiari malformation associated with atlantoaxial dislocation are presented. A lateral plate and screw fixation was performed in all cases. Reversal foramen magnotomy was performed in three cases and two patients underwent the conventional posterior bony decompression for Chiari malformation. In an average postoperative follow-up period of 8 months (range 3 months to 2 years) neurological symptoms and signs improved in all patients, with radiological and clinical evidence of bony union and stability of the craniovertebral region. The surgical problems encountered in such cases where a posterior decompression was required in addition to a fixation procedure are enumerated in this report. The advantages of the proposed operations are described.