The Effect of Ganglion Sphenopalatine Block (GSP-block) Versus Placebo on Postdural Puncture Headache

Adult patients with postdural puncture headache will be enrolled in the study. The patients will be randomised to receive a ganglion sphenopalatine block (GSP‐block) with either local anesthetic (lidocaine + ropivacaine) or placebo (isotone NaCl). Primary outcome is hyperactivity in the sphenopalatine ganglion assessed by pain intensity (0‐100mm on a visual analogue scale, VAS) of the postdural headache in standing position 30 minutes after block. If the patients in the timeframe of 1 hour to 1 week after block does not achieve remission (VAS <30mm while standing) they will be offered a "rescue GSP‐block" defined as a new GSP‐block with "open‐label" local anesthetic and if continued lack of remission at least 1 hour thereafter then an epidural blood patch will be offered.