An unusual complication of extradural catheterization in obstetric anaesthesia.

An extradural catheter was inserted at the third lumbar interspace for relief of pain during labour in a 21-year-old gravid patient. Attempts to withdraw the catheter met with resistance and produced severe pain in the distribution of the second left lumbar nerve. Radiography revealed an acutely angled loop of the catheter over the L2-3 nerve root.