ABSTRACT
A scientific basis for the application of intrathecal opioids was first laid in 1970s when highly specific opioid receptors were discovered in the nervous system of rats and primates [1]. Subsequently, opioid receptors were identified in the substantia gelatinosa of the dorsal root entry zone of the human spinal cord [2]. Clinical effectiveness of intrathecal morphine was demonstrated by Wang [3] in 1979 and since then, the idea of intrathecal drug delivery for pain control has gained wide acceptance in medical circles.
