[Accidental catheterization of the subdural space: a complication of continuous spinal anesthesia and continuous peridural anesthesia].

Two cases of subdural catheter placement following continuous spinal and continuous epidural anaesthesia are presented. In the first, despite an easy reflux of clear cerebrospinal fluid through the catheter, the injection of 4 ml bupivacaine 0.5 per cent with epinephrine 1:200,000 followed by 3 ml tetracaine 0.5 per cent showed a failure of spinal anesthesia. In the second, the administration through the catheter of 20 ml lidocaine 2.0 per cent CO2 plus epinephrine 1:200,000 and of ten ml bupivacaine 0.5 per cent lead to an insufficient, patchy and asymmetrical analgesia. The clinical signs observed in these two cases are compared with previous publications. The importance of an x-ray contrast study to confirm the diagnosis of subdural catheter insertion is stressed.