POSTERIOR-FOSSA DECOMPRESSION FOR CHIARI-I DEFORMITY, INCLUDING RESECTION OF THE CEREBELLAR TONSILS

This is an analysis of 19 consecutive cases of symptomatic patients wi th Chiari I deformities, undertaken to evaluate the long-term effect o f posterior fossa decompression and duraplasty, assessed by postoperat ive imaging. Sixteen of the patients had syringomyelia and three had f oramen magnum syndromes without a syrinx. Eighteen patients underwent posterior fossa craniectomy, subpial resection of the cerebellar tonsi ls, and duraplasty. Four patients were 16 years of age or younger. One of the children with syringomyelia had a posterior fossa decompressio n without resection of the tonsils. In the 15 patients with syringomye lia whose surgery included resection of the tonsils, the syrinx was re duced or resolved in 14. The patient whose syrinx did not change was a child with a lumbosacral lipoma. Three patients had syndromes of the foramen magnum without a syrinx, and of these only a patient with prio r chemical and bacterial meningitis caused by a lumboureteral shunt fa iled to improve dramatically. When our patients are combined with 40 i n the literature treated by decompression and duraplasty, 51 of 55 pat ients had reduction or resolution of the syrinx. Although it does not clearly affect the result, resection of the tonsils can be done safely .