The pathophysiology of cervical and upper thoracic sympathetic surgery
The main effect of upper thoracic sympathectomy is sudomotor. To abolish sweating of the palms, T2 ganglionectomy (often with the addition of T3) was invariably performed. To prevent axillary sweating, additional T4 ablation was recommended. Sympathectomy produces a vasodilatatory cutaneous effect. The circulation in the muscles, however, is unaltered or may even be reduced. It also appears that improved skin blood flow is on the thermoregulatory, not nutritive level. It seems that chronic surgical sympathectomy does not cause major changes in the vascular function of the forearm. Although the exact pathophysiological mechanism of blushing is still obscure, bilateral upper dorsal sympathectomy alleviates this phenomenon. T2-T3 ganglionectomy significantly decreases pulse rate and systolic blood pressure, reduces myocardial oxygen demand, increases left ventricular ejection fraction and prolongs Q-T interval. A certain loss of lung volume and decrease of pulmonary diffusion capacity for CO result from sympathectomy. Histomorphological muscle changes and neuro-histochemical and biochemical effects have also been observed.