alterations in the three-phase bone scan in acute CRPS are similar to those resulting from sympathectomy

There is only limited evidence regarding the efficacy of thoracoscopic or surgical sympathectomy. Four studies reported partial long-lasting benefits in CRPS types 1 and 2.

Postoperatively, no vasoconstriction due to deep inspiration (vasoconstrictor reflex) could be elicited at the affected extremity, indicatin complete sympathetic denervation. Additionally the temperature at the affected hand increased. After 4 weeks, skin temperature decreased, without signs of reinnervation. This denervation supersensitivity was associated with recurrence of pain and is thought to rely on a vascular supersensitivity to could and circulating catecholamines.

Interestingly, alterations in the three-phase bone scan in acute CRPS are similar to those resulting from sympathectomy without being related to the success of the intervention. (p.370)

The neurological basis of pain

By Marco Pappagallo
McGraw-Hill Professional, 2005 - Medical - 673 pages