Optic nerve sheath diameter as a prognostic tool for postdural puncture headache in pregnant women undergoing caesarean section under spinal anesthesia: A cross-sectional study

Context: Postdural puncture headache (PDPH) is a common and debilitating complication following spinal anesthesia in obstetric patients, with few objective tools available for early prediction. Optic nerve sheath diameter (ONSD) measured by ultrasonography is a noninvasive surrogate marker of intracranial pressure changes and may aid in early risk stratification. Aim: To evaluate the prognostic utility of ONSD measurements in predicting PDPH among pregnant women undergoing cesarean section under spinal anesthesia. Materials and Methods: This cross-sectional study included 88 pregnant women aged between 18 and 40 years undergoing cesarean section under spinal anesthesia. ONSD was measured using ultrasonography with a 13–6 MHz probe at baseline (T0) and at 4 (T4), 24 (T24), 48 (T48), and 72 h (T72) postprocedure. PDPH was diagnosed using International Classification of Headache Disorders criteria. Statistical Analysis Used: Data were analyzed using SPSS version 22. Continuous variables were expressed as mean ± SD and categorical variables as frequencies and percentages. Student’s t -test and Chi-square/Fischer’s exact test were used as appropriate. Diagnostic performance was assessed using sensitivity, specificity, predictive values, and ROC curve analysis with calculation of area under the curve (AUC). Results: PDPH occurred in 12 patients (13.6%). Baseline ONSD values were comparable between groups. Patients who developed PDPH showed significantly lower ONSD values from T4 onward ( P < 0.05). The best diagnostic performance was at T72 (AUC 0.776; 95% CI 0.663–0.889) with a cutoff ≤4.52 mm, yielding 91.7% sensitivity, 69.7% specificity, and 98.1% negative predictive value. ONSD reduction from baseline at T72 was significantly greater in the PDPH group ( P < 0.001). Conclusion: ONSD measurement at 72 h postspinal anesthesia is a sensitive and clinically useful prognostic tool for predicting PDPH in obstetric patients and may be incorporated into routine postoperative monitoring.