The Journal of Bone and Joint Surgery, Vol 73, Issue 6 898-906, Copyright © 1991 by Journal of Bone and Joint Surgery, Inc
Instability of the cervical spine after decompression in patients who have Arnold-Chiari malformation
DD Aronson, RH Kahn, A Canady, RO Bollinger and R Towbin
Department of Orthopaedic Surgery, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit.
Stability of the cervical spine was studied in two groups of children who
had myelomeningocele. Group I consisted of twenty children who had an
Arnold-Chiari Type-II malformation in whom a suboccipital craniectomy
(partial occipital craniectomy through the suboccipital route) and cervical
laminectomy was done to decompress the brain stem. The average duration of
follow-up in this group (excluding one patient) was 4.7 years (range, 2.3
to 10.4 years) after the operation. Group II consisted of twenty children
who had myelomeningocele but had not had an operation for decompression.
Lateral radiographs of the cervical spine in flexion and extension showed
no instability between the occiput and atlas or between the atlas and axis
in either group. In contrast, translation between the second and third
cervical vertebrae averaged four millimeters in Group I and one millimeter
in Group II (p less than 0.01), and angulation between the third and fourth
cervical vertebrae averaged 17 degrees in Group I and 6 degrees in Group II
(p less than 0.01). Nineteen of the twenty patients in whom a suboccipital
craniectomy and cervical laminectomy (Group I) had been done had
instability of the cervical spine.