1 Central Integration of Pain in Humans (NeuroPain), Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5092, University Claude Bernard Lyon 1, France
1 Central Integration of Pain in Humans (NeuroPain), Lyon Neuroscience Research Center, Inserm U1028, CNRS UMR 5092, University Claude Bernard Lyon 1, France.
Brain. 2016 Mar;139(Pt 3):708-22. doi: 10.1093/brain/awv389. Epub 2016 Feb 8.
Thalamic pain is a severe and treatment-resistant type of central pain that may develop after thalamic stroke. Lesions within the ventrocaudal regions of the thalamus carry the highest risk to develop pain, but its emergence in individual patients remains impossible to predict. Because damage to the spino-thalamo-cortical system is a crucial factor in the development of central pain, in this study we combined detailed anatomical atlas-based mapping of thalamic lesions and assessment of spinothalamic integrity using quantitative sensory analysis and laser-evoked potentials in 42 thalamic stroke patients, of whom 31 had developed thalamic pain. More than 97% of lesions involved an area between 2 and 7 mm above the anterior-posterior commissural plane. Although most thalamic lesions affected several nuclei, patients with central pain showed maximal lesion convergence on the anterior pulvinar nucleus (a major spinothalamic target) while the convergence area lay within the ventral posterior lateral nucleus in pain-free patients. Both involvement of the anterior pulvinar nucleus and spinothalamic dysfunction (nociceptive thresholds, laser-evoked potentials) were significantly associated with the development of thalamic pain, whereas involvement of ventral posterior lateral nucleus and lemniscal dysfunction (position sense, graphaesthesia, pallaesthesia, stereognosis, standard somatosensory potentials) were similarly distributed in patients with or without pain. A logistic regression model combining spinothalamic dysfunction and anterior pulvinar nucleus involvement as regressors had 93% sensitivity and 87% positive predictive value for thalamic pain. Lesion of spinothalamic afferents to the posterior thalamus appears therefore determinant to the development of central pain after thalamic stroke. Sorting out of patients at different risks of developing thalamic pain may be achievable at the individual level by combining lesion localization and functional investigation of the spinothalamic system. As the methods proposed here do not need complex manipulations, they can be added to routine patients' work up, and the results replicated by other investigators in the field.
丘脑痛是一种严重且治疗抵抗的中枢性疼痛，可能在丘脑卒中后发生。丘脑腹侧尾侧区域的病变发生疼痛的风险最高，但在个别患者中其发生仍无法预测。由于脊髓丘脑系统的损伤是中枢性疼痛发展的关键因素，因此在这项研究中，我们结合了基于详细解剖图谱的丘脑病变定位和使用定量感觉分析和激光诱发电位对脊髓丘脑完整性的评估，共纳入 42 例丘脑卒中患者，其中 31 例发生了丘脑痛。超过 97%的病变累及前连合平面上方 2-7mm 的区域。尽管大多数丘脑病变影响多个核团，但中枢性疼痛患者的病变最大收敛于前丘（主要的脊髓丘脑靶位），而在无疼痛患者中收敛区位于腹后外侧核内。前丘的受累和脊髓丘脑功能障碍（痛觉阈值、激光诱发电位）均与丘脑痛的发生显著相关，而腹后外侧核和脊索功能障碍（位置感、图形觉、触觉、立体觉、标准躯体感觉诱发电位）在有或无疼痛的患者中分布相似。将脊髓丘脑功能障碍和前丘受累结合作为回归因子的逻辑回归模型对丘脑痛的敏感性为 93%，阳性预测值为 87%。因此，脊髓丘脑传入纤维对后丘脑的损伤似乎是丘脑卒中后发生中枢性疼痛的决定因素。通过结合病变定位和脊髓丘脑系统的功能研究，对不同发生丘脑痛风险的患者进行分类可能在个体水平上实现。由于这里提出的方法不需要复杂的操作，因此可以添加到常规的患者检查中，并且该领域的其他研究人员可以复制结果。
