title: Ball-valve effect of a contaminated spinal needle.
authors.forename: I M
authors.initials: IM
authors.lastname: Bishton
authors.forename: M J
authors.initials: MJ
authors.lastname: Clark
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000775:Anesthesia, Spinal / Q000295:instrumentation*; D001769:Blood; D004866:Equipment Contamination; D004868:Equipment Failure; D006801:Humans; D008297:Male; D009339:Needles