The aim of our study is to test the hypothesis whether ultrasonographically measured ultrasound-guided optic nerve sheath diameter (US-ONSD) decreases after lumbar puncture (LP) and whether decreased optic nerve sheath diameter (ONSD) after lumbar puncture is associated with headache. The latter might help to identify patients with postdural puncture headache (PDPH). In this prospective observational study 76 patients, who had undergone diagnostic LP using an atraumatic technique, received a measurement of ONSD before (T0), immediately after (T1) and 24 h after LP (T2). Additionally demographic data such as age, sex, body mass index (BMI), and also headaches and symptoms were recorded. In six out of 7 patients with constant PDPH, we additionally measured ONSD 48 h (T3) and 72 h (T4) after LP. All patients (n = 76, 100%) showed a physiological reduction in ONSD at T1. Patients with consistent symptoms of PDPH (n = 7, 9%) kept values below pre-LP levels after 24 and 48 h. No statistical difference was found in BMI, sex, cerebrospinal fluid volume, needle size, or previous headaches between the PDPH (n = 7, 9%) and non-PDPH patients (n = 69, 91%). Younger patients were more likely to experience PDPH symptoms. Since at T2 the ONSD was only reduced in PDPH patients, a significant difference in ONSD was found between PDPH and non-PDPH patients. The cut-off value of ONSD for predicting PDPH at T2 was 4.9 mm in the receiver operating characteristic (ROC) curve (sensitivity 86%, specificity 93%). We were able to demonstrate a physiologic change in ONSD after LP in all patients. The sonographic measurement of ONSD in patients with headache can help to identify and monitor PDPH after LP.
Merzou et al. (Fri,) studied this question.