title: The epidural blood patch: are more than two ever necessary?
mesh_terms: D000328:Adult; D001769:Blood; D004824:Epidural Space; D005260:Female; D006261:Headache / Q000209:etiology* / Q000628:therapy; D006801:Humans; D011187:Posture; D013115:Spinal Canal; D013129:Spinal Puncture / Q000009:adverse effects*; D013997:Time Factors