Toward a simpler surgical management of Chiari I malformation in a pediatric population

A wide variety of surgical adjuvants to the standard bony decompression have been advocated in the treatment of the Chiari I malformation, especially when the tonsillar herniation is associated with hydrosyringomyelia. These include various shunting procedures, duroplasty, obex plugging, and resection of the cerebellar tonsils. Our practice has been to avoid these adjuvants and to perform a simple limited occipital craniectomy, C1 laminectomy, and dural opening. The dura mater is left open and overlain with oxidized cellulose. To evaluate the efficacy of this more limited procedure, a retrospective review was performed of the medical records of 31 consecutive patients treated over a 6-year period. Twenty-six (84%) of these patients had an associated spinal cord syrinx; all underwent the same procedure. The follow-up period ranged from 15 to 93 months, with all patients having at least one postoperative magnetic resonance imaging at 6 months. Twenty-three of the 26 patients (88%) who presented with a syrinx had significant resolution of the syrinx on follow-up scans with concomitant improvement of presenting signs and symptoms. Of the remaining 3 patients, 1 had progressive hydrocephalus and received a ventriculoperitoneal shunt, with symptom resolution. In the other 2 patients the syrinx did not diminish; both received syringopleural shunts. Postoperative morbidity includes a 26% incidence of headaches, of which half resolved within 5 days, and only 1 persisted beyond 2 weeks. Nausea and vomiting occurred in 16%. Neither of these figures significantly exceeds those of other large surgical series in which the dura mater was closed with a patch graft. Three patients (10%) did have a postoperative cerebrospinal fluid leak; all responded to bedside suturing without further sequelae. This study indicates that a simple bone removal and open dural decompression of the cervicomedullary junction is a safe, effective operative treatment for Chiari I malformation in children. Shunts, duroplasty, obex plugging, and tonsillar resection offer no benefit regarding the outcome when our series is compared to others in which such adjuvants were used.