Risk factors for recurrence of post-dural puncture headache following an epidural blood patch: a retrospective cohort study.

INTRODUCTION: Post-dural puncture headache (PDPH) occurs in 0.38-6.3% of neuraxial procedures in obstetrics. Epidural blood patch (EBP) is the standard treatment but fails to provide full symptom relief in 4-29% of cases. Knowledge of the risk factors for EBP failure is limited and controversial. This study aimed to identify these risk factors.

METHODS: We performed a retrospective cohort study using electronic records of 47920 patients who underwent a neuraxial procedure between 2001 and 2018 in a large maternity hospital in Switzerland. The absence of full symptom relief and the need for further treatment was defined as an EBP failure. We performed univariate and multivariate analyses to compare patients with a successful or failed EBP.

RESULTS: We identified 212 patients requiring an EBP. Of these, 55 (25.9%) had a failed EBP. Signs and symptoms of PDPH did not differ between groups. While needle size and multiple pregnancies were risk factors in the univariate analysis, mostly those related to the performance of the EBP remained significant following adjustment. The risk of failure increased when the epidural space was deeper than 5.5 cm (OR 3.08, 95% CI 1.26 to 7.49) and decreased when the time interval between the initial dural puncture and the EBP was >48 h (OR 0.20, 95% CI 0.05 to 0.83).

CONCLUSION: Persistence of PDPH following a first EBP is not unusual. Close attention should be given to patients having their EBP performed <48 h following injury and having an epidural space located >5.5 cm depth, as these factors are associated with a failed EBP.