Timing of neuraxial pain interventions following blood patch for post dural puncture headache.

Post dural puncture headache (PDPH) is a common complication of interventional neuraxial procedures. Larger needle gauge, younger patients, low body mass index, women (especially pregnant women), and "traumatic" needle types are all associated with a higher incidence of PDPH. Currently, an epidural blood patch is the gold-standard treatment for this complication. However, despite the high PDPH cure rate through the use of this therapy, little is known about the physiology behind the success of the epidural blood patch, specifically, the time course of patch formation within the epidural space or how long it takes for the blood patch volume to be resorbed by the body. Of the many unanswered and debated topics related to PDPH and epidural blood patches, one additional specific question that may alter clinical management is when it is safe for patients who have experienced a disruption of the thecal space and have undergone this procedure to have a subsequent epidural or spinal procedure, such as a neuraxial anesthetic (i.e. a spinal anesthetic for an elective outpatient procedure) or an interventional pain procedure for chronic pain management. This question becomes more unclear if the new procedure includes a steroid medication. As an example, an older patient presents with a history of lumbar disc disease and during lumbar epidural steroid injection, an inadvertent wet tap occurs leading to PDPH. Following management with fluids, caffeine, medications, and a successful epidural blood patch, it remains unclear as to when would be the best time frame to consider a second lumbar epidural steroid injection. We identified the 3 main risk factors of subsequent interventional neuraxial procedures as (1) disruption of the epidural blood patch and ongoing reparative processes, (2) epidural procedure failure, and (3) infection. We looked at the literature, and summarized the existing literature in order to enable health care professionals to understand the time course of dural repair as well as the risks of subsequent neuraxial procedures after epidural blood patches. This review poses the question using an evidence based review to discuss the appropriate time course to proceed.