Efficacy of peripheral nerve blockade in patients with post-stroke central post-stroke pain

Wang Xiujing; Li Lingcong; Wang Zhenyu

doi:10.11986/j.issn.1673-873X.2023.12.009

Abstract：Objective This study aimed to explore the clinical efficacy of peripheral nerve blockade in patients with central post-stroke pain(CPSP)and the role of primary afferents in CPSP.Methods This study included 22 CPSP patients admit-ted to the Department of Rehabilitation Medicine at the Affiliated Yongchuan Hospital of Chongqing Medical University be-tween March and December 2022.They were randomly allocated to receive lidocaine blockade treatment or placebo control treatment,with 11 patients in each group.Both groups underwent peripheral nerve blockade under ultrasound guidance at the site of pain.The lidocaine blockade group received an injection of 2％lidocaine containing 1:200 000 epinephrine,while the placebo control group received an injection of isotonic saline.Pain Numeric Rating Scale(NRS)scores,evoked response scores,and lidocaine blood concentration were evaluated before and after treatment in both groups.Results All patients ex-perienced mechanical and/or temperature sensitivity in the pain area contralateral to the cerebral lesion.The degree of spon-taneous pain relief in the lidocaine blockade group was significantly superior to that in the placebo control group[(-82.8± 16.3)％vs.(-1.8±21.3)％;P＜0.05].In the lidocaine blockade group,spontaneous pain was significantly relieved af-ter 7 minutes of treatment,and an upward trend in NRS scores was observed after 1 hour of treatment.Four patients in the lidocaine blockade group still had low NRS scores at 8 hours after treatment.In the placebo control group,most patients had a slight increase in NRS scores at 2 minutes after treatment,which gradually returned to the pre-treatment pain scores.At T30,the evoked response scores in the pain area of the lidocaine blockade group were significantly lower than those in the placebo control group(P＜0.05).At T30,the evoked response scores in the lidocaine blockade group for cotton swabs,monofilament needle puncture,cold stimulation,and heat stimulation were significantly lower than those at T0(P＜0.05).However,no statistically significant difference was found in the evoked response scores in the pain area of the placebo con-trol group for cotton swabs,monofilament needle puncture,cold stimulation,and heat stimulation compared to T0(P＞0.05).Conclusion Peripheral nerve blockade demonstrates alleviating effects on CPSP,with a high safety profile.Primary sensory input plays an important role in the maintenance of pain in CPSP patients,which may open up new perspectives for targeted treatment of CPSP.