Privitera Rosario, Birch Rolfe, Sinisi Marco, Mihaylov Iordan R, Leech Robert, Anand Praveen
Peripheral Neuropathy Unit, Centre for Clinical Translation, Hammersmith Hospital, Imperial College London, London, UK.
Peripheral Nerve Injury Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK.
J Pain Res. 2017 Jul 13;10:1623-1634. doi: 10.2147/JPR.S140925. eCollection 2017.
The aim of this study was to measure the efficacy of a single 60 min application of capsaicin 8% patch in reducing chronic amputation stump and phantom limb pain, associated hypersensitivity with quantitative sensory testing, and changes in brain cortical maps using functional MRI (fMRI) scans.
A capsaicin 8% patch (Qutenza) treatment study was conducted on 14 patients with single limb amputation, who reported pain intensity on the Numerical Pain Rating Scale ≥4/10 for chronic stump or phantom limb pain. Pain assessments, quantitative sensory testing, and fMRI (for the lip pursing task) were performed at baseline and 4 weeks after application of capsaicin 8% patch to the amputation stump. The shift into the hand representation area of the cerebral cortex with the lip pursing task has been correlated with phantom limb pain intensity in previous studies, and was the fMRI clinical model for cortical plasticity used in this study.
The mean reduction in spontaneous amputation stump pain, phantom limb pain, and evoked stump pain were -1.007 (=0.028), -1.414 (=0.018), and -2.029 (=0.007), respectively. The areas of brush allodynia and pinprick hypersensitivity in the amputation stump showed marked decreases: -165 cm, -80% (=0.001) and -132 cm, -72% (=0.001), respectively. fMRI analyses provided objective evidence of the restoration of the brain map, that is, reversal of the shift into the hand representation of the cerebral cortex with the lip pursing task (<0.05).
The results show that capsaicin 8% patch treatment leads to significant reduction in chronic pain and, particularly, in the area of stump hypersensitivity, which may enable patients to wear prostheses, thereby improving mobility and rehabilitation. Phantom limb pain ("central" pain) and associated brain plasticity may be modulated by peripheral inputs, as they can be ameliorated by the peripherally restricted effect of the capsaicin 8% patch.
本研究旨在评估单次使用60分钟8%辣椒素贴剂对减轻慢性截肢残端和幻肢疼痛、定量感觉测试相关的超敏反应以及使用功能磁共振成像（fMRI）扫描观察脑皮质图谱变化的效果。
对14名单肢截肢患者进行了8%辣椒素贴剂（Qutenza）治疗研究，这些患者报告慢性残端或幻肢疼痛的数字疼痛评分量表疼痛强度≥4/10。在基线时以及将8%辣椒素贴剂应用于截肢残端后4周进行疼痛评估、定量感觉测试和fMRI（用于噘嘴任务）。在先前的研究中，噘嘴任务时大脑皮质手部代表区的变化与幻肢疼痛强度相关，并且是本研究中使用的皮质可塑性fMRI临床模型。
自发截肢残端疼痛、幻肢疼痛和诱发残端疼痛的平均减轻分别为-1.007（=0.028）、-1.414（=0.018）和-2.029（=0.007）。截肢残端的刷状痛觉过敏和针刺超敏反应区域显著减少：分别为-165平方厘米、-80%（=0.001）和-132平方厘米、-72%（=0.001）。fMRI分析提供了脑图谱恢复的客观证据，即噘嘴任务时大脑皮质手部代表区的变化逆转（<0.05）。
结果表明，8%辣椒素贴剂治疗可显著减轻慢性疼痛，尤其是残端超敏反应区域，这可能使患者能够佩戴假肢，从而改善活动能力和康复情况。幻肢疼痛（“中枢性”疼痛）及相关的脑可塑性可能受到外周输入的调节，因为8%辣椒素贴剂的外周局限性作用可使其得到改善。
