Hôpital Sacré-Cœur de Montréal (HSCM), Montreal, QC, Canada.
Département de psychologie, de l'Université de Montréal, Montreal, QC, Canada.
PLoS One. 2020 Mar 20;15(3):e0226452. doi: 10.1371/journal.pone.0226452. eCollection 2020.
Primary motor (M1) cortical excitability alterations are involved in the development and maintenance of chronic pain. Less is known about M1-cortical excitability implications in the acute phase of an orthopedic trauma. This study aims to assess acute M1-cortical excitability in patients with an isolated upper limb fracture (IULF) in relation to pain intensity.
Eighty-four (56 IULF patients <14 days post-trauma and 28 healthy controls). IULF patients were divided into two subgroups according to pain intensity (mild versus moderate to severe pain). A single transcranial magnetic stimulation (TMS) session was performed over M1 to compare groups on resting motor threshold (rMT), short-intracortical inhibition (SICI), intracortical facilitation (ICF), and long-interval cortical inhibition (LICI).
Reduced SICI and ICF were found in IULF patients with moderate to severe pain, whereas mild pain was not associated with M1 alterations. Age, sex, and time since the accident had no influence on TMS measures.
These findings show altered M1 in the context of acute moderate to severe pain, suggesting early signs of altered GABAergic inhibitory and glutamatergic facilitatory activities.
初级运动（M1）皮质兴奋性的改变与慢性疼痛的发生和维持有关。对于矫形外伤急性期 M1 皮质兴奋性的影响，我们知之甚少。本研究旨在评估孤立上肢骨折（IULF）患者急性 M1 皮质兴奋性与疼痛强度的关系。
84 名患者（56 名 IULF 患者<14 天，28 名健康对照者）。根据疼痛强度（轻度与中重度疼痛），IULF 患者分为两组。对 M1 进行单次经颅磁刺激（TMS），比较两组静息运动阈值（rMT）、短程皮质内抑制（SICI）、皮质内易化（ICF）和长程皮质内抑制（LICI）。
中重度疼痛的 IULF 患者 SICI 和 ICF 降低，而轻度疼痛与 M1 改变无关。年龄、性别和事故发生后的时间对 TMS 测量无影响。
这些发现表明急性中重度疼痛时 M1 改变，提示 GABA 能抑制性和谷氨酸能易化性活动改变的早期迹象。
