Unsuccessful lumbar puncture in a paediatric patient with achondroplasia.

We present a case of an unsuccessful lumbar puncture performed on an anaesthetised 17-year-old girl with achondroplasia who was diagnosed with and being treated for acute lymphoblastic leukaemia. Magnetic resonance imaging (MRI) subsequently showed spinal stenosis and no observable cerebrospinal fluid around the nerve roots at the levels of the lumbar pedicles and discs. A recommendation is made to obtain MRI scans before proceeding with lumbar puncture and/or spinal anaesthesia in this patient group to ensure that the anatomical features of the insertion site are favourable to a successful outcome.