Postulated Mechanisms for Post Dural Puncture Headache: Clinical Experience and Review Of Laboratory Models

In the 1950's, the generally accepted theory for the development of post dural puncture headache (PDPH) was leakage of cerebrospinal fluid via the hole in the dura which led to the introduction of smaller sized needles for dural puncture. This has lowered but not eliminated the incidence of PDPH. The literature has virtually as many different statistics on the incidence of PDPH as there are authors. The purpose of this manuscript is to answer the following question: "Why doesn't every patient have PDPH after a dural puncture?" The answer to this question holds the key to eliminating the problem of PDPH. For the first time, it is possible to investigate the reasons for the absence of PDPH. Specifically, the bending of the needle is presented as the major factor why so many patients do not get PDPH. The author's experience with 4465 spinal anesthetics using a 20 gauge sharp beveled needle with the lateral approach and without apparent headache suggested a review to determine whether the angle of puncture is related to the incidence of PDPH. This review will attempt to answer this question by elucidating laboratory work done in this area, citing clinical studies, and including personal observations and experiments.