To the Editor.—In the July 1988 issue of the Archives,1 Kotagal and Fischer recommend that, when performing lumbar puncture, one should keep the needle bevel parallel to the long axis of the spine. On pure theoretical grounds, the resulting puncture hole in the dura will be smaller this way. It has, however, never been shown that adhering to this rule will actually result in diminishing the percentage of patients with post–lumbar puncture headache. A study like that would be very worthwhile, but, until now, has not been undertaken. Because this theoretical concept is not backed up with clinical research, it is perhaps too early to suggest that this advice should be printed in the internal medicine and pediatrics textbooks.
In a similar case it was recently shown that oblique or tangential insertion of the needle does not prevent post–lumbar puncture headache.2 In theory this technique was also