Recovery of sympathetic nerve function after lumbar sympathectomy is slower in the hind limbs than in the torso

Local sympathetic denervation by surgical sympathectomy is used in the treatment of lower limb ulcers and ischemia,but the restoration of cutaneous sympathetic nerve functions is less clear.This study aims to explore the recovery of cutaneous sympathetic functions after bilateral L2-4 sympathectomy.The skin temperature of the left feet,using a point monitoring thermometer,increased intraoperatively after sympathectomy.The cytoplasm of sympathetic neurons contained tyrosine hydroxylase and dopamineβ-hydroxylase,visualized by immunofluorescence,indicated the accuracy of sympathectomy.Iodine starch test results suggested that the sweating function of the hind feet plantar skin decreased 2 and 7 weeks after lumbar sympathectomy but had recovered by 3 months.Immunofluorescence and western blot assay results revealed that norepinephrine and dopamineβ-hydroxylase expression in the skin from the sacrococcygeal region and hind feet decreased in the sympathectomized group at 2 weeks.Transmission electron microscopy results showed that perinuclear space and axon demyelination in sympathetic cells in the L5 sympathetic trunks were found in the sympathectomized group 3 months after sympathectomy.Although sympathetic denervation occurred in the sacrococcygeal region and hind feet skin 2 weeks after lumbar sympathectomy,the skin functions recovered gradually over 7 weeks to 3 months.In conclusion,sympathetic functional recovery may account for the recurrence of hyperhidrosis after sympathectomy and the normalization of sympathetic nerve trunks after incomplete injury.The recovery of sympathetic nerve function was slower in the limbs than in the torso after bilateral L（2-4） sympathectomy.

Lower limb pain in sympathetic-sensory coupling

Previous studies have shown that sympathetic nerves are related to certain types of pain, and this phenomenon is referred to as sympathetic-sensory coupling. Chronic pain resulting from nerve injury can be exacerbated by sympathetic stimulation or relieved by sympathetic inhibition. In the present study, the correlation between pain and sympathetic nerves was analyzed in patients with severe pain in lower limbs, as we^l as in a chronically compressed dorsa~ root ganglion ~CCD） rat model （model of low back pain and sciatica）. Patients with severe pain in the lower limbs underwent chemical lumbar sympathectomy （CLS）, and the analgesic effects of CLS were compared with painkillers. Results demonstrated significantly relieved lower limb pain following CLS, and the analgesic effects of CLS were superior to those seen with painkillers. In the CCD rat model, dorsal root ganglion neuronal activity significantly increased as a result of electrical stimulation to the sympathetic nerves. These results suggest that sympathetic nerves are closely associated with pain and sympathetic-sensory coupling is likely in lower limb pain in both patients and rat models of CCD.