Migration of an extradural catheter into the subdural space. A case report.

After repeated, successful extradural injections in a parturient, the extradural catheter migrated into the subdural space. The injection of 3% chloroprocaine 10 ml resulted in an extensive block, which extended to the cranial nerves and paralysed the respiratory muscles. The position of the catheter tip was confirmed by fluoroscopy. Subdural injection should always be suspected when tests for subarachnoid injection are negative, but an extensive block occurs gradually within 15-20 min. Respiration and circulation should be supported until the block regresses.