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

Objective: 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.

Methods: We retrospectively reviewed medical records of patients who attended Xuanwu Hospital between January 2018 and July 2019 with persistent or recurrent syringomyelia after FMD.

Results: 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.

Conclusions: 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.