Craniocervical spinal instability after type 1 Arnold Chiari decompression: a case report.

To present and describe an unusual case of spinal instability after craniocervical spinal decompression for a type-1 Chiari malformation. Type-1 Chiari malformation is a craniocervical disorder characterized by tonsillar displacement greater than 5 mm into the vertebral canal; posterior fossa decompression is the most common surgical treatment for this condition. Postoperative complications have been described: cerebrospinal fluid leak, pseudomeningocele, aseptic meningitis, wound infection, and neurological deficit. However, instability after decompression is unusual. A 9-year-old female presented with symptomatic torticollis after cervical decompression for a type-1 Chiari malformation. Spinal instability was diagnosed; craniocervical stabilization was performed. After a 12-month follow-up, spinal stability was achieved, with a satisfactory clinical neck alignment. We present a craniocervical instability secondary to surgical decompression; clinical and radiological symptoms, and definitive treatment were described.