Dural taps revisited. A 20-year survey from Birmingham Maternity Hospital.

The records from 34,819 obstetric epidurals performed at Birmingham Maternity Hospital over the period 1969-1988 were examined. During that time there were 460 dural taps (overall incidence 1.3%). Of the methods used to detect the epidural space, loss of resistance to injection of saline was associated with the lowest incidence of dural tap (0.6%). The incidence of typical postdural puncture headache when managed conservatively was 86%. Provision of an epidural drip after delivery reduced the incidence of headache to 70%. Elective forceps delivery conferred no additional benefit, and tended to delay the onset of headache. Blood patches were performed on 135 patients and provided complete relief of headache in 93 (68%). A further 23 patients (16%) obtained partial relief.