Bony Decompression for Chiari Malformation Type I: Long-Term Follow-Up

Several surgical techniques are used for the management of Chiari malformation type I (CM-I). Bony posterior fossa decompression is considered a good option in children, though with a higher risk of requiring reoperation. However, there is not enough evidence from the series in the literature, which are often limited by inadequate follow-up. The goal of this study was to assess the effectiveness of suboccipital craniectomy alone in children after long-term follow-up.

Forty-two children (25 female and 17 male; mean age 6.7 years), operated on with bony decompression alone, were retrospectively reviewed. All patients underwent suboccipital craniectomy. Thirty-eight children required C1 laminectomy, and 21 also underwent dural delamination on the basis of intraoperative ultrasound investigations. The outcome was assessed using the traditional measurement and the Chicago Chiari Outcome Scale (CCOS). The mean follow-up period was 11.3 years (range 5-15 years).

Headache was the most frequent preoperative symptom (81%), followed by neck pain (40%), vertigo (40%), ataxia (26%), and upper and lower extremity paraesthesia (26%). Syringomyelia was present in 19 patients (45%). Resolution and significant improvement of preoperative clinical symptoms were observed in 36.5% and 21.5% of cases, respectively. Three children required adjunctive surgery for symptom recurrence (7%). The tonsil position and syringomyelia were normalized or improved in 50% and 79% of cases, respectively. No complications occurred. According to the CCOS scores, 69.5% of children had an excellent outcome, 28.5% had a functional outcome and 2% had an impaired outcome.

Bony decompression alone is an effective, safe and long-lasting treatment for children with CM-I. A certain risk of symptom recurrence requiring new surgery exists, but it is widely counterbalanced by the low risk of complications. Careful patient selection is crucial for a good outcome. Prospective and randomized studies are needed for further validation.