Current practice of diagnostic lumbar puncture.

cutaneous sphincterotomy is the treatment of choice for patients with chronic anal fissure. Both procedures are easily and safely performed in the outpatient department under local anaesthesia, thereby avoiding the costs and disruption of admission to hospital. SHORT REPORTS Current practice of diagnostic lumbar puncture About 30%1 of patients have a headache after lumbar puncture,' and many studies have examined its cause and prevention. As some of these studies have been imprecise or contradictory we surveyed current practice for diagnostic lumbar puncture. We contacted a junior doctor from each of the neurology departments of 15 London teaching or postgraduate institutions and 13 provincial university hospitals. These 28 doctors, most of whom worked for more than one neuro-logist, completed a telephone questionnaire. All 28 had performed a lumbar puncture: six estimated that they had performed fewer than 10, four from 10 to 20, three from 20 to 30, six from 30 to 40, five from 40 to 50, and four more than 50. Twenty four of the doctors had forewarned their patients of the possibility of headache. Seventeen used 18 or 19 standard wire gauge (SWG) needles, six 20 SWG needles, and five 22 SWG needles. The amount of cerebrospinal fluid removed was: 1-5 ml (one doctor), 2-3 ml (one), 3-5 ml (10), 6-10 ml (14), and 15 ml (two). To help prevent headache three doctors allowed immediate mobilisation, one advised half an hour of bedrest, one advised two hours, two advised three hours, two advised four hours, seven advised six hours, one advised eight hours, three advised 12 hours, and eight advised 24 hours. Ten doctors advised drinking plenty of water. All the doctors agreed on bedrest and analgesia when the patient had an established headache. In addition, one doctor used the head down position and three prescribed steroids. Epidural blood patching was not used. Only seven doctors claimed to have received any instruction on policy from senior colleagues (five from registrars and two from consultants). Comment The cause of headache after lumbar puncture is persistent leakage of cerebrospinal fluid through the dural puncture hole made by the spinal needle. This produces cerebrospinal fluid hypotension, intracranial venous dilatation, and headache due to stimulation of pain sensitive nerve endings. There is no difference in the incidence of headache whether dural puncture is made alone or up to 25 ml fluid is removed, emphasising the magnitude of the leak.2 Surprisingly, 12 doctors …