title: Recordings of, and an anatomical explanation for, false positive loss of resistance during lumbar extradural analgesia.
abstract: Loss of resistance dorsal to the ligamentum flavum was recorded in 10 of 16 patients aged 43--75 yr whilst performing extradural anaesthesia at the L2--3 interspace via the midline approach. Degeneration of the interspinous ligament with cavity formation is observed frequently in the elderly and may account for false positive loss of resistance and failure to obtain analgesia following the injection of local anaesthetic.
mesh_terms: D000328:Adult; D000368:Aged; D000767:Anesthesia, Epidural / Q000379:methods; D003560:Cysts / Q000503:physiopathology; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008022:Ligaments / Q000502:physiology; D008159:Lumbar Vertebrae / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011312:Pressure; D013122:Spinal Diseases / Q000503:physiopathology