Local pain and spreading hyperalgesia induced by intramuscular injection of nerve growth factor are not reduced by local anesthesia of the muscle.

Objectives: Injections with local anesthesia for therapeutic and diagnostic purposes are common clinical practice. This double-blind placebo controlled study explores the rational of local anesthetic blocks for the detection of muscle pain as the primary generator in spreading hyperalgesic conditions.

Methods: Experimental muscle pain was induced by injections of nerve growth factor (NGF) in the left and right supraspinatus muscle of 11 healthy volunteers.