Chronified Pain Following Operative Procedures.

BACKGROUND: Over 18 million operative procedures are performed each year in Germany alone. Approximately 10% of surgical patients develop moderate to severe chronic post-surgical pain (CPSP), which can severely impair their quality of life. The pain must persist for at least three months to be called chronic; pain that arises after a symptom-free interval is not excluded. The perioperative use of local anesthetic agents may lessen the incidence of CPSP. METHODS: We selectively reviewed the pertinent literature, including two current Cochrane Reviews. Local and regional anesthetic techniques are discussed, as is the intravenous administration of lidocaine. RESULTS: The main risk factors for CPSP are pre-existing (preoperative) chronic pain, opioid intake, a pain-related catastrophizing tendency, intraoperative nerve injury, and severe acute postoperative pain. CPSP is reported to be especially common after thoracic surgery, breast surgery, amputations, and orthopedic procedures. Local and regional anesthetic techniques have been shown to significantly lower the incidence of CPSP after thoracotomy (number needed to treat for an additional beneficial outcome [NNTB] = 7), breast cancer surgery (NNTB = 7), and cesarean section (NNTB = 19). Intravenous lidocaine also lowers the incidence of CPSP after various types of procedures. CONCLUSION: Local and regional anesthetic techniques and intravenous lidocaine lower the incidence of CPSP after certain types of operative procedures. The intravenous administration of lidocaine to prevent CPSP is off label and requires the patient's informed consent. The evidence for the measures presented here is of low to medium quality.

Referred cramping phantom hand pain elicited in the face and eliminated by peripheral nerve block.

Phantom limb pain is a restricting condition for a substantial number of amputees with quite different characteristics of pain. Here, we report on a forearm amputee with constant phantom pain in the hand, in whom we could regularly elicit the rare phenomenon of referred cramping phantom pain by touching the face. To clarify the underlying mechanisms, we followed the cramp during the course of an axillary blockade of the brachial plexus. During the blockade, both phantom pain and the referred cramp were abolished, while a referred sensation of "being touched at the phantom" persisted. Furthermore, to identify the cortical substrate, we elicited the cramp during functional magnetic imaging. Imaging revealed that referred cramping phantom limb pain was associated with brain activation of the hand representation in the primary sensorimotor cortex. The results support the hypothesis that referred cramping phantom limb pain in this case is associated with a substantial brain activation in the hand area of the deafferented sensorimotor cortex. However, this alone is not sufficient to elicit referred cramping phantom limb pain. Peripheral inputs, both, from the arm nerves affected by the amputation and from the skin in the face at which the referred cramp is evoked, are a precondition for referred cramping phantom limb pain to occur, at least in this case.