OAA Small Project Grant
Does Magnetic Resonance Imaging (MRI) correlate with severity of headache following accidental dural puncture (ADP) during epidural catheter placement for labour
analgesia?
Dr Roshan Fernando
In the UK 1 in 3 women choose an epidural for pain relief during childbirth, as it remains the most effective choice. Pain sensation is conveyed to the brain via nerves that are connected through the spinal cord, which floats in a bag of fluid (dural sac) further protected inside a hollow bony column (vertebral column).
The dural sac contains fluid (cerebrospinal fluid or CSF), and its coverings are made of three layers of membranes (dura mater, arachnoid mater and pia mater). The spinal cord is connected directly with the brain, and the dural sac and covering membranes continue upwards in the skull to enclose the brain. An epidural involves placement of a plastic tube by an anaesthetic doctor, through a needle, into a space that lies between the outermost membrane of the sac and the wall of the bony canal (epidural space).
In an uncomplicated procedure, this placement of the plastic tube is achieved without puncturing the membranes. However, in 1% cases, the dura may get punctured by the needle leading to the leakage of spinal fluid. It is believed that such a leakage causes traction on the membranes producing headache in 80% of women (called postdural puncture headache or PDPH). If severe this may require an invasive procedure (called an epidural blood patch or EBP) for effective treatment.
PDPH can be very incapacitating and debilitating for the new mother; restricting daily activities, impairs looking after her baby, impedes mother-baby bonding and can delay discharge from hospital. In simple terms, PDPH can turn an enjoyable experience into an unpleasant one, with substantial physical, emotional and psychological consequences.
Currently, there is no scientific investigative tool that can predict the development, progress and severity of PDPH. Current management relies on a "wait and watch" strategy. This has serious limitations, including unnecessary suffering for the new mother by delayed diagnosis, potentially delayed definitive treatment (EBP), and premature discharge with subsequent readmission.
Magnetic resonance imaging (MRI) is a routine investigation tool, frequently used in other fields of medicines (neurology, neurosurgery etc), that can provide high-resolution images of the spinal cord, its surrounding membranes, spinal fluid and its leakage into the epidural space.
This study will be the first attempt to scientifically evaluate the link between features identified on MRI images taken soon after accidental puncture of the dura, and the development, progress and severity of ensuing headache. This may help clinicians to reliably identify the patients at risk of developing more severe headache and offer early institution of effective treatment (EBP), on the basis of scientific evidence instead of the current "wait, watch and intervene" strategy. We believe this would help to reduce unnecessary suffering for the new mother and minimise the disruption to family life due to PDPH.
