title: Management of Chiari I malformation in children: effectiveness of intra-operative ultrasound for tailoring foramen magnum decompression.
abstract: OBJECTIVE
  Patients with Chiari I malformation (CM-1) commonly undergo foramen magnum decompression (FMD). However, there is no consensus on how this should be achieved. An approach would be to rationalize surgical steps based on pre-operative imaging and intra-operative findings. The aim of this study is to assess the usefulness of intra-operative ultrasound scanning (IOUS) in tailoring foramen magnum decompression in children with CM-1 and whether the use of IOUS is effective in reducing the risk of complications without increasing the need for re-operation.
  
  
  METHODS
  We performed a retrospective study. IOUS was utilized during FMD: a subjective assessment was made on whether there was adequate cerebellar tonsillar and/or CSF pulsation following suboccipital craniectomy. If there was adequate pulsation, the dura was not opened. Additional data were collected including age and gender of patients, presence of pre-operative syringomyelia, intra-operative ultrasound findings, length of follow-up, complications and radiological and clinical outcome. The statistical analysis was performed with XLStat®(Addinsoft SARL™, France).
  
  
  RESULTS
  Nineteen patients underwent FMD from June 2011 to December 2012. The mean age was 10.5 years; there were nine females and ten males. Eleven patients had syringomyelia at diagnosis. Based on IOUS, eight patients underwent dural decompression and 11 patients bony decompression only. One patient had a post-operative pseudomeningocoele and two patients required re-operation. There was no significant statistical difference between the two groups regarding post-operative improvement in the syrinx.
  
  
  CONCLUSIONS
  We found that tailoring FMD for patients with CM-1 using intra-operative findings using ultrasound scan was useful in avoiding unnecessary manoeuvres, while not compromising on the outcome.
authors: Department of Paediatric Neurosurgery, Alder Hey Children's Hospital NHS Foundation Trust, Eaton Road, Liverpool, L12 2AP, UK.
authors: Ganesalingam
authors: G
authors: Narenthiran
authors: Christopher
authors: C
authors: Parks
authors: Benedetta
authors: B
authors: Pettorini
mesh_terms: D000293:Adolescent; D001139:Arnold-Chiari Malformation / Q000000981:diagnostic imaging* / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D056424:Decompressive Craniectomy / Q000379:methods*; D005260:Female; D005539:Foramen Magnum / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D014463:Ultrasonography