Purpose <p>Idiopathic syringomyelia represents a group of patients with a syrinx without an underlying pathological cause. Patients may present with back pain, leg pain and/or neurological dysfunction. We aim to examine the clinico-radiological outcomes of paediatric patients presenting with idiopathic syringomyelia managed with a therapeutic lumbar puncture.</p> Methods <p>All paediatric patients with idiopathic syringomyelia who underwent a lumbar puncture over a 10-year time period were identified and included. Pre- and post-procedural clinico-radiological features were obtained from electronic patient records. Procedural details, including opening pressure and drainage volume, were obtained from electronic operative records.</p> Results <p>31 patients underwent a therapeutic lumbar puncture. Median age at time of first lumbar puncture was 12&#xa0;years (range 2–17). 7/31 (23%) patients had significant long-term improvement or resolution in their symptoms following a single lumbar puncture. 13/31 (42%) patients had temporary improvement of their symptoms and underwent further lumbar punctures. 3/31 (10%) patients had resolution of their symptoms after more than one lumbar puncture. 8/31 (26%) patients did not experience any improvement in their symptoms. Symptomatic improvement was more likely in those with a high opening pressure of equal to or greater than 24cmH₂O (OR 13 (1.3 – 126.3) <i>P</i> = 0.02). Median length of follow up was 3 yrs (range 6&#xa0;months – 9&#xa0;years). Complications occurred in 9/31 (29%) patients, with 8 of these experiencing a low pressure headache, and 1 patient experiencing temporary back pain following the lumbar puncture.</p> Conclusion <p>Lumbar puncture may be a safe and effective treatment for symptomatic idiopathic syringomyelia in the paediatric population. It appears to be more effective in those with a higher opening pressure.</p>