Objective  To explore the effect of ultrasound-guided continuous lumbar sympathetic ganglion (LSG) block on the pain mediators and degree in patients with intractable pain of lower extremity.

  Methods  Totally 100 patients with intractable pain of lower extremity were selected and randomly divided into drug group and block group, with 50 cases in each group. The drug group was treated with gabapentin and mecobalamin, and the block group was treated with ultrasound-guided continuous LSG block. The pain mediators calcitonin gene-related peptide (CGRP), β-endorphin (β-EP), 5-hydroxytryptamine (5-HT), pain degree visual analogue score (VAS), skin temperature, and adverse reactions were compared between the two groups.

  Results  The CGRP, β-EP and 5-HT levels after treatment in drug group and block group were significantly lower than those before treatment, the block group was significantly lower than those in drug group (P < 0.05). At 1 and 7 days after treatment, the VAS scores in drug group and block group were significantly lower than those before treatment, and the VAS scores at 1 and 7 days after treatment in block group were significantly lower than those in drug group (P < 0.05). At 1 and 7 days after treatment, skin temperature in drug group and block group were significantly higher than those before treatment, and skin temperature at the 1 and 7 days after treatment in block group were significantly higher than those in drug group (P < 0.05). There was no significant difference in the incidence of adverse reactions between the drug group and block group (P>0.05).

  Conclusion  Ultrasound-guided continuous LSG block can effectively reduce the release of pain mediators in patients with intractable pain of lower extremity, improve the pain degree and skin temperature, and has better safety.