Repeat Craniocervical Decompression in Patients with a Persistent or Worsening Syrinx: A Preliminary Report and Early Results

Abstract

Foramen magnum decompression (FMD) remains the first-line treatment for Chiari malformation type I associated with syringomyelia, although consistent approaches are not used. However, there are few reports on a persistent or recurrent syrinx or worsening neurologic symptoms after FMD. We retrospectively reviewed medical records of patients who attended Xuanwu Hospital between January 2018 and July 2019 with persistent or recurrent syringomyelia after FMD. All 8 patients had syringomyelia preoperatively with a mean disease course of 43 (range, 3-120) months and underwent FMD. The presenting symptoms improved in 1 patient. There was radiologic evidence of decreased syrinx size in 1 patient. Worsening syringomyelia presented at a median of 65 (range, 7-168) months after the primary FMD. Secondary decompression was performed in all patients. A structural, pathological cause for the first FMD failure was identified in all cases at the time of the second decompression. Symptoms were resolved in all patients after repeat decompression surgery. Radiologically, 6 patients had a decrease in syringomyelia size. The level of the upper segment of the syringomyelia was higher in 7 of our revision patients, among which 6 patients had a decrease in syringomyelia size. The median follow-up duration after the secondary decompression was 11.5 (range, 6-22) months. Adults with persistent syringomyelia after FMD and the higher level of the upper segment of the syringomyelia often have a surgically remediable structural cause. The beneficial effect of a secondary decompression should be considered and guide the decision-making of patients with Chiari malformation type I-related syringomyelia.