Smits H, Ultenius C, Deumens R, Koopmans G C, Honig W M M, van Kleef M, Linderoth B, Joosten E A J
Pain Management and Research Center, Department of Anaesthesiology, Maastricht University Hospital, P. Debyelaan 25, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
Neuroscience. 2006 Dec 1;143(2):541-6. doi: 10.1016/j.neuroscience.2006.08.007. Epub 2006 Sep 15.
Spinal cord stimulation (SCS) is an established treatment for chronic neuropathic pain. However, in recent studies conflicting results regarding the effect of SCS were noted in a selected group of patients suffering from complex regional pain syndrome and mechanical allodynia. In the present study we investigated the pain relieving effect of SCS in a rat experimental model of neuropathic pain as related to the severity of mechanical allodynia. Adult male rats (n=45) were submitted to a unilateral sciatic nerve ligation. The level of allodynia was tested using the withdrawal response to tactile stimuli with the von Frey test. A portion of these rats developed marked tactile hypersensitivity in the nerve-lesioned paw (von Frey test), similar to "tactile allodynia" observed after nerve injury in humans. Prior to SCS treatment the rats were subdivided into three groups based on the level of allodynia: mild, moderate and severe. All allodynic rats were treated with SCS (n=27) for 30 min (f=50 Hz; pulse width 0.2 ms and stimulation at 2/3 of motor threshold) at 16 days post-injury. Our data demonstrate a differential effect of SCS related to the severity of the mechanical allodynia. SCS leads to a faster and better pain relief in mildly allodynic rats as compared with the more severely allodynic rats. Thus, we suggest that the selection and subdivision of patient groups similar to those defined in our experimental setting (mild, moderate and severe allodynic) may provide better pre-treatment prediction of possible therapeutic benefits of SCS.
脊髓刺激（SCS）是治疗慢性神经性疼痛的一种既定疗法。然而，在最近的研究中，在一组患有复杂性区域疼痛综合征和机械性异常性疼痛的特定患者中，关于SCS效果的结果相互矛盾。在本研究中，我们在神经性疼痛的大鼠实验模型中研究了SCS的止痛效果，并将其与机械性异常性疼痛的严重程度相关联。成年雄性大鼠（n = 45）接受单侧坐骨神经结扎。使用von Frey试验通过对触觉刺激的退缩反应来测试异常性疼痛的程度。这些大鼠中的一部分在神经损伤的爪子中出现了明显的触觉超敏反应（von Frey试验），类似于人类神经损伤后观察到的“触觉异常性疼痛”。在SCS治疗前，根据异常性疼痛的程度将大鼠分为三组：轻度、中度和重度。所有异常性疼痛大鼠在损伤后16天接受SCS治疗（n = 27）30分钟（频率 = 50 Hz；脉冲宽度0.2 ms，刺激强度为运动阈值的2/3）。我们的数据表明SCS的效果与机械性异常性疼痛的严重程度存在差异。与异常性疼痛更严重的大鼠相比，SCS在轻度异常性疼痛大鼠中能更快、更好地缓解疼痛。因此，我们建议，类似于我们实验设定中定义的患者组（轻度、中度和重度异常性疼痛）的选择和细分，可能会为SCS可能的治疗益处提供更好的治疗前预测。
