Objective: To assess outcome in patients with syrinx and non-syrinx associated Chiari malformations undergoing Foramen Magnum Decompression (FMD).

Methods: 61 patients undergoing FMD for Chiari malformations were prospectively studied with disease specific, generic (SF 36) and subjective (surgeon assessed) outcomes. 34 patients had complete data. Disease specific outcomes were visual analogue pain scores, Neck and Myelopathy disability indices and the Hospital anxiety and depression score. SF 36 scores were compared to normative data. Data were collected pre-operatively, at 3 months and during long-term follow up (12–60 months).

Results: Subjective improvements in headache and neck pain post-operatively were seen in both syrinx and non-syrinx associated patients. Visual Analogue scores showed an improvement in Arm pain, Paraesthesia and Hand tingling by 3 months in the syrinx group only. Non-syrinx patients showed significant improvement post-operatively in the Neck disability index and the SF-36 domains for physical function, role physical and bodily pain by 12 months. Comparison with the SF 36 normative data showed that patients still have significantly impaired quality of life 12 months post operatively despite the improved scores achieved following surgery.

Conclusion: FMD is able to relieve symptoms and improve quality of life in patients with both syrinx and non-syrinx associated Chiari malformations. The SF-36 data presented in this paper allows the health gain associated with FMD to be quantified but its utility as a sole measure of outcome in this complex disorder will be discussed.

Ethics approval: None

Interest Statement: None