In Reply:—

We appreciate the interest and the comments of Dr. Aya et al.  regarding our article. 1Our study included all patients treated with an epidural blood patch (EBP) for incapacitating postdural puncture headache (PDPH) in our hospital, from all medical and surgical specialties, including obstetrical patients. The incidence of accidental dural puncture during epidural anesthesia (performed with Tuohy needles) is low. Indeed, only 68 of our patients (13% of 504 treated patients) underwent dural puncture with Tuohy needles in our study. In obstetrical patients alone, the first EBP permitted complete relief of symptoms in 66% (45/68), incomplete relief of symptoms in 13% (9/68), and failure in 21% (14/68) of them, contrary to the global population (including obstetrical patients) where these results are respectively 75%, 18%, and 7%. As noted in the letter by Dr. Aya et al. , the low percentage of our patients who had dural puncture with large bore needles probably explains the high success rate of EBP in our study, and explains why only 7% of the patients required a second EBP. Grouping these patients permitted us to perform the multivariate analysis, and to observe that the large diameter of the needle performing the dural puncture was a predictive factor of failure of EBP. This important information would most likely have been missed if only obstetric patients with accidental dural puncture by Tuohy needles had been studied.

We agree with Dr. Aya et al.’s  remarks concerning obstetrical patients who have severe PDPH complicating epidural anesthesia. No study (neither Loeser et al.’s  study, 2nor our's 1) can actually support the claim that delaying EBP from dural puncture could increase its effectiveness. However, it is important to inform patients in advance of the average success and failure rates of a first EBP, and of the possible necessity of performing a second EBP. This information must be tailored according to the diameter of the needle that is used to perform the dura mater puncture. This information might allow for a better acceptance of EBP failure by patients, and therefore, a better acceptance of a second EBP. In our opinion, these elements and the safety of the EBP favor early EBP realization in patients with severe PDPH after dural puncture with a large bore needle, including obstetrical patients.

Safa-Tisseront V, Thormann F, Malassiné P, Henry M, Riou B, Coriat P, Seebacher J: Effectiveness of epidural blood patch in the management of post-dural puncture headache. A nesthesiology 2001; 95: 334–9
Loeser EA, Hill GB, Bennett GM, Sederberg JH: Time vs success rate for epidural blood patch. A nesthesiology 1978; 49: 147–8