Foramen Magnum Decompression for Chiari Malformation Type 1: Is There a Superior Surgical Technique?

Foramen magnum decompression is a common operation used to treat Chiari malformation. There are different surgical techniques; however, some are anecdotally more effective than others. Our aim was to determine whether there is a superior technique in relation to revision rates, presence of persistent postoperative headache and nausea, and syrinx reduction.

This was a retrospective analysis of foramen magnum decompressions performed between 2012 and 2017 for Chiari 1 in a single institution. Three types of operations were performed: 1) bony decompression alone; 2) bony decompression with durotomy and dura left open; 3) bony decompression with opening of dura and duraplasty. We compared postoperative symptoms and revision rates between these 3 operations.

In 168 patients, 185 foramen magnum decompressions were performed. Among the 168 primary operations, in 66 the dura was not opened, in 86 the dura was opened without a duraplasty, and in 16 a duraplasty was performed. Of 185 operations, 17 were revision surgery. For primary procedures, the revision rates were 12 (18%) where the dura was not opened, 4 (5%) where the dura was left open, and 1 (6%) when duraplasty was performed. Severe postoperative headache and nausea occurred in 2 (3%) patients where the dura was not opened, 4 (25%) patients after primary duraplasty, and 64 (74%) patients after primary durotomy.

In this study, rate of revision surgery was highest in patients who had bony decompression without dural opening. Rate of postoperative headache and nausea was highest in the durotomy group. Overall duraplasty had the best results.