Sudden onset of subarachnoid block after subdural catheterization: A case of arachnoid rupture?

Abstract

We describe a patient who received an apparently uneventful extradural block in labour but developed vapid extension of neural block within minutes of receiving her first incremental dose 2h later. Computed contrast tomography revealed radio-opaque dye within both the subdural and subarachnoid spaces, but none within the extradural space. This case report demonstrates that subdural spread of low-dose local anaesthetics is not always clinically distinguishable from extradural analgesia and that the arachnoid membrane may subsequently perforate with potentially serious consequences.