Managing Post–Dural Puncture Headache with Lumbar Epidural Blood Patch: Is It Effective? Safa-Tisseront et al. (page 334)Between December 1988 and October 2000, Safa-Tisseront et al. included in an observational study all patients treated at their institution with lumbar epidural blood patch (EBP) for incapacitating post–dural puncture headache. Their aim was to assess the effectiveness of EBP as a treatment and to determine what factors, if any, were predictive of treatment failure.During the 12-yr study period, 527 patients were included in the study; 504 were included in the final analysis. Diagnosis criteria for severe post–dural puncture headache included inability to perform daily activities and necessity to stay in bed for part of the day. In patients included in the study, dural puncture had occurred during anesthesia (both spinal and epidural), diagnostic lumbar puncture, or therapeutic lumbar puncture. Their symptoms included headache in 97% of cases, neck pain in 87%, nausea and vomiting in 60%, cochlear symptoms in 36%, and ocular symptoms in 36%. EBP was performed after a median delay of 4 days after dural puncture. The mean volume of blood injected was 23 ± 5 ml.Complete relief of symptoms occurred in 377 cases, and incomplete relief occurred in 93 cases; the treatment failed in 34 cases. The authors analyzed patient characteristics, circumstances of dural puncture, delay between dural puncture and EBP, and volume of blood injected for EBP. They determined that only the diameter of the needle (< 20 gauge) and a delay of treatment of more than 4 days were independently predictive of treatment failure.