The spinal needle as a carrier of foreign material.
D000775:Anesthesia, Spinal / Q000009:adverse effects*; D005547:Foreign Bodies / Q000209:etiology; D006261:Headache / Q000209:etiology; D006801:Humans; D008722:Methods; D011183:Postoperative Complications; D013129:Spinal Puncture / Q000009:adverse effects*; D013525:Surgical Instruments