Electron Microscopy of Dural and Arachnoid Disruptions After Subarachnoid Block

( Reg Anesth Pain Med 2017;42:709–718) Postdural puncture headache (PDPH) is commonly explained by intracranial hypotension due to cerebrospinal fluid leakage. An association between larger size dural punctures and an increased incidence of PDPH has been widely accepted. It was generally believed that pencil-point type needles produced smaller dural lesions by allowing separation rather than cutting of the dural fibers, but this has not been supported by morphologic evidence. There has been little investigation on the morphology of dural lesions produced by spinal needles. This study aimed to study human meninges and the morphology of dura-arachnoid lesions produced by 27 G Whitacre and 29 G Quincke spinal needles. The study also sought to determine whether there was a correlation between the diameter of the lesions and the needles used. Finally, authors aimed to determine whether the lesion diameter was altered when the 29 G needle bevel was oriented vertically rather than horizontally.