Abstract
Since nerve blocks in conjunction with local anesthetics have dramatic pain relieving effects in the treatment of acute pain, they also have been used for treatment of chronic persistent pain. In most cases of intractable pain, the original pain relapses after the short period of relief afforded by nerve blocks. Because nerve block is an invasive technique, it should not be used frequently to obtain temporary effects, but should be avoided as much as possible by using other analgesic measures. Alternatively, it might be beneficial if physical and psychosocial functions in chronic pain patients can be restored through its pain relieving effects.
Although nerve blocks have been used for diagnosis and prognosis in patients with persistent pain, simple interpretation of the results might be misleading in determination of follow-up treatment. Therefore, the results should be interpreted in consideration of various factors affecting the sensitivity and specificity of nerve block. It is unclear wether or not they prevent the transition of acute pain to chronic persistent pain, though they have been empirically used.
In this article, I describe mainly the roles of sympathetic nerve block in complex regional pain syndrome and postherpetic neuralgia which are well-known diseases associated with persisitent pain.
