title: MR determination of neonatal spinal canal depth.
abstract: OBJECTIVE
  Lumbar punctures (LPs) are frequently performed in neonates and often result in traumatic haemorrhagic taps. Knowledge of the distance from the skin to the middle of the spinal canal (mid-spinal canal depth - MSCD) may reduce the incidence of traumatic taps, but there is little data in extremely premature or low birth weight neonates. Here, we determined the spinal canal depth at post-mortem in perinatal deaths using magnetic resonance imaging (MRI).
  
  
  METHODS
  Spinal canal depth was measured in 78 post-mortem foetuses and perinatal cases (mean gestation 26 weeks; mean weight 1.04kg) at the L3/L4 inter-vertebral space at post-mortem MRI. Both anterior (ASCD) and posterior (PSCD) spinal canal depth were measured; MSCD was calculated and modelled against weight and gestational age.
  
  
  RESULTS
  ASCD and PSCD (mm) correlated significantly with weight and gestational age (all r>0.8). A simple linear model MSCD (mm)=3×Weight (kg)+5 was the best fit, identifying an SCD value within the correct range for 87.2% (68/78) (95% CI (78.0, 92.9%)) cases. Gestational age did not add significantly to the predictive value of the model.
  
  
  CONCLUSIONS
  There is a significant correlation between MSCD and body weight at post-mortem MRI in foetuses and perinatal deaths. If this association holds in preterm neonates, use of the formula MSCD (mm)=3×Weight (kg)+5 could result in fewer traumatic LPs in this population.
authors.affiliation: Centre for Cardiovascular MR, Great Ormond Street Hospital for Children, London WC1N 3JH, UK. owenarthurs@uk2.net
authors.forename: Owen
authors.initials: O
authors.lastname: Arthurs
authors.forename: Sudhin
authors.initials: S
authors.lastname: Thayyil
authors.forename: Angie
authors.initials: A
authors.lastname: Wade
authors.forename: W K Kling
authors.initials: WK
authors.lastname: Chong
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Sebire
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Taylor
mesh_terms: D002102:Cadaver; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009929:Organ Size / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013115:Spinal Canal / Q000033:anatomy & histology* / Q000254:growth & development*