Long-term white matter changes after severe traumatic brain injury: a 5-year prospective cohort.

BACKGROUND AND PURPOSE: Extensive white matter damage has been documented in patients with severe traumatic brain injury, yet how this damage evolves in the long term is not well understood. We used DTI to study white matter changes at 5 years after traumatic brain injury. MATERIALS AND METHODS: There were 8 healthy control participants and 13 patients with severe traumatic brain injury who were enrolled in a prospective observational study, which included clinical assessment and brain MR imaging in the acute setting (< 6 weeks) and 2 years and 5 years after injury. Only subjects with mild to moderate disability or no disability at 1 year were included in this analysis. DTI parameters were measured in 20 different brain regions and were normalized to values obtained in an age-matched control group. RESULTS: In the acute setting, fractional anisotropy was significantly lower in the genu and body of the corpus callosum and in the bilateral corona radiata in patients compared with control participants, whereas radial diffusivity was significantly (P < .05) higher in these tracts. At 2 years, fractional anisotropy in these tracts had further decreased and radial diffusivity had increased. No significant changes were detected between 2 and 5 years after injury. The baseline radial diffusivity and fractional anisotropy values in the anterior aspect of the brain stem, genu and body of the corpus callosum, and the right and left corona radiata were significantly (P < .05) associated with neurocognitive sequelae (including amnesia, aphasia, and dyspraxia) at year 5. CONCLUSIONS: DTI changes in major white matter tracts persist up to 5 years after severe traumatic brain injury and are most pronounced in the corpus callosum and corona radiata. Limited structural change is noted in the interval between 2 and 5 years.

An observational study of factors leading to difficulty in resident anaesthesiologists identifying the epidural space in obstetric patients.

BACKGROUND: Multiple attempts at needle placement for neuraxial block may cause patient discomfort, a higher incidence of spinal haematomas, postdural puncture headache and nerve trauma. The aim of this study was to evaluate the factors predicting difficult epidural analgesia for inexperienced residents. METHODS: In this prospective observational study, conducted in a teaching hospital, four anaesthesiology residents without prior experience in obstetric anaesthesia performed all epidural procedures. A difficult epidural was defined as a need for more than one attempt at catheter placement. The following patient data were recorded: body mass index, abdominal circumference (classified as <105 or ≥ 105 cm), ability to palpate anatomical landmarks and spinal abnormality. RESULTS: Four hundred and twelve pregnant women in labour were recruited. Residents achieved successful cannulation of the epidural space in 74% of attempts. Factors associated with difficult epidural placement in the univariate analysis were body mass index > 30 kg/m(2), an abdominal circumference > 105 cm, inability to palpate spinous processes and spinal abnormality. With the exception of abdominal circumference, all factors were independently predictive of difficult placement in the multivariate analysis with spinal abnormality being the most significant factor. CONCLUSIONS: For residents with no prior experience in obstetric anaesthesia, the most reliable factor in predicting difficult epidural cannulation was spinal abnormality.