Dealing with post-dural puncture headache--is it different in obstetrics?

Abstract

p OST-DURAL puncture headache (PDPH) won't go away. The message is dear: the incidence and severity of PDPH is related to the size of the hole in the dura. This type of headache is more common in younger people, and more prevalent in women than in men. It occurs more ftequently in people who are prone to headaches. Pregnancy per se does not increase the relative risk of PDPH. The high incidence of spinal headache in obstetric patients may be explained by age and sex. 1 Numerous studies and reports have chronided the benefits of using small gauge, pencil point needles when performing deliberate lumbar puncture for anaesthesia or diagnostic procedures. 2 Young obstetric patients frequently undergo spinal anaesthesia for Caesarean section, and anaesthetists now use needles designed to minimise the incidence of PDPH, which remains around 1%. This is considered an acceptable risk. Obstetric patients are unique, however, in that they are likely to suffer accidental dural puncture with a large bore epidural needle designed to introduce catheters into the epidural space. The incidence of this complication varies with the experience of the anaesthetist, and is 0.5-2.5% in teaching hospitals. 3 When unintentional dural puncture occurs, 30 to 70% of the parturients get the headache. The variance is explained by the direction of the needle in relation to the dural fibres when the entry occurs. 4 I f the epidural needle is introduced parallel to the longitudinal dural fibres, the incidence of PDPH is much less. When PDPH develops in the obstetric patient, the morbidity is considerable. The new mother is incapacitated, she may be unable to get out of bed to care for her baby or herself. The cost of health care increases, because she may need to stay in hospital longer than planned. Treatment options for the condition are not particularly satisfactory. Pharmacological treatment is variable at best. Intravenous or oral caffeine give variable results. Epidural or intravenous saline infusions have not been shown to be of much use. Bed rest is no longer recommended. Recent reports on the successful use of subcutaneous sumatriptan to treat the headache merits further study, s I f the mother is too distressed to get up and move, the epidural blood patch is still the best treatment, although it is not as successful as previously thought. Early reports suggested that epidural blood patches were 90% successful in curing the headache. It is now known that the headache recur in 15-30% ofparients even after a successful initial patch, and permanent cure is only achieved in about 60% of patients after one blood patch. 6 Repeating the blood patch once may improve the headache in another 20%, but more than two blood patches is not recommended. Blood patching is not without side effects and complications. Patients may be reluctant to undergo this treatment because another epidural needle must be inserted, with the risk of repeat dural puncture. Back pain is common, perhaps due to tracking of blood back into the subcutaneous fat. 7 The risk of infection, albeit rare, should not be discounted. A recent report described postpartum dural venous sinus thrombosis after a blood patch, s A number of legal claims have resulted from PDPH in Canada. Although all have been dismissed, the incidence of this complication in anaesthetic practice is high enough to warrant warning all patients that it can occur. This will decrease costs associated with medicolegal defence. Since treatment of PDPH, a self limiting condition, may be unsatisfactory, ineffective or risky, any prophylactic measure that can consistently prevent the headache is worth investigating. In this issue, Dennehy and Rosaeg 9 report that in three cases, insertion of an intrathecal catheter after accidental dural puncture, and leaving that catheter in situ for more than 12 hr, was effective in preventing PDPH. They discuss two previous reports with the same findings (Deunehy's References #5 and 14). Cohen et al. left the catheter in place after Caesarean section, and used it to provide intrathecal patient controlled pain relief with fentanyl and bupivacaine. That, in itself,