Type of needle used in anesthesia not linked to post-dural puncture headache, study shows

The type of needle used in certain kinds of anesthesia is not linked to post-dural puncture headache (PDPH), a serious and potentially life-threatening complication, according to a recent study.

The study, published in the latest issue of Regional Anesthesia and Pain Medicine, debunks myths about the cause of post-dural puncture headaches. The severe headaches are caused by a puncture of the dura mater – one of the membranes surrounding the brain and spinal cord – and are a serious complication of epidural anesthesia, other nerve blocks, and diagnostic lumbar puncture.

Because any tear or hole in the membrane surrounding the spinal cord can allow the surrounding fluid to leak, it is typical to attribute the resulting post-dural headache incidence and severity to the size and nature of the needle used – and the resulting hole created during the procedure. However, the team of researchers from Spain and Australia determined through the use of electron microscopy that neither needle-tip orientation nor tip characteristics of small needles have much impact on the lesion produced.

The small needles in daily clinical use produce holes that almost immediately recoil upon removal of the needle such that the overlapping layers of dura matter render the lesion much smaller than at the time of puncture, according to primary investigator Dr. Miguel Angel Reina. Cerebral spinal fluid (CSF) leakage continues until the deeper layer of the membrane is completely sealed.

Dural fibers tend to have a 'memory' to close back the hole created by the spinal needle, whereas arachnoid mater has less capacity to do so. The development of PDPH and its resolution are a more complex process that involves many more steps than previously thought, the authors conclude.