Kvarnström A, Karlsten R, Quiding H, Gordh T
Department of Anaesthesiology and Intensive Care, University Hospital, Uppsala, Sweden.
Acta Anaesthesiol Scand. 2004 Apr;48(4):498-506. doi: 10.1111/j.1399-6576.2003.00330.x.
Pain following spinal cord injury (SCI) is a therapeutic challenge. Only a few treatments have been assessed in randomized, controlled trials. The primary objective of the present study was to examine the analgesic effect of ketamine and lidocaine in a group of patients with neuropathic pain below the level of spinal cord injury. We also wanted to assess sensory abnormalities to see if this could help us to identify responders and if treatments resulted in changes of sensibility.
Ten patients with spinal cord injury and neuropathic pain below the level of injury were included. The analgesic effect of ketamine 0.4 mg kg(-1) and lidocaine 2.5 mg kg(-1) was investigated. Saline was used as placebo. The drugs were infused over 40 min. A randomized, double-blind, three-period, three-treatment, cross-over design was used. Systemic plasma concentrations of ketamine and lidocaine were assessed. Pain rating was performed using a visual analogue scale (VAS). Sensory function was assessed with a combination of traditional sensory tests and quantitative measurement of temperature thresholds.
Response to treatment, defined as 50% reduction in VAS-score during infusion, was recorded in 5/10 in the ketamine, 1/10 in the lidocaine and 0/10 in the placebo groups. Neither ketamine nor lidocaine changed temperature thresholds or assessments of mechanical; dynamic and static sensibility. Nor could these sensory assessments predict response to treatment in this setting. Lidocaine and particularly ketamine were associated with frequent side-effects.
Ketamine but not lidocaine showed a significant analgesic effect in patients with neuropathic pain after spinal cord injury. The pain relief was not associated with altered temperature thresholds or other changes of sensory function.
脊髓损伤（SCI）后的疼痛是一项治疗挑战。仅有少数治疗方法在随机对照试验中得到评估。本研究的主要目的是检验氯胺酮和利多卡因对一组脊髓损伤平面以下神经性疼痛患者的镇痛效果。我们还想评估感觉异常，以确定这是否有助于我们识别反应者，以及治疗是否会导致感觉变化。
纳入10例脊髓损伤且损伤平面以下存在神经性疼痛的患者。研究了0.4mg/kg氯胺酮和2.5mg/kg利多卡因的镇痛效果。使用生理盐水作为安慰剂。药物在40分钟内输注。采用随机、双盲、三阶段、三治疗、交叉设计。评估氯胺酮和利多卡因的全身血浆浓度。使用视觉模拟量表（VAS）进行疼痛评分。结合传统感觉测试和温度阈值定量测量来评估感觉功能。
氯胺酮组10例中有5例、利多卡因组10例中有1例、安慰剂组10例中无1例记录到对治疗的反应，即输注期间VAS评分降低50%。氯胺酮和利多卡因均未改变温度阈值或机械感觉评估；动态和静态感觉。在这种情况下，这些感觉评估也无法预测对治疗的反应。利多卡因尤其是氯胺酮伴有频繁的副作用。
氯胺酮而非利多卡因对脊髓损伤后神经性疼痛患者显示出显著的镇痛效果。疼痛缓解与温度阈值改变或其他感觉功能变化无关。
