Department of Anesthesiology, University of California San Diego, San Diego, California, USA
The Outcomes Research Consortium, Cleveland, Ohio, USA.
Reg Anesth Pain Med. 2023 Sep;48(9):471-477. doi: 10.1136/rapm-2023-104389. Epub 2023 Mar 9.
We previously reported that a 6-day continuous peripheral nerve block reduces established postamputation phantom pain. To provide patients and providers with the information to best inform treatment decisions, here we reanalyze the data and present the results in a more patient-centered format. We also provide information on patient-defined clinically relevant benefits to facilitate evaluation of available studies and guide future trial design.
The original trial enrolled participants with a limb amputation and phantom pain who were randomized to receive a 6-day continuous peripheral nerve block(s) of either ropivacaine (n=71) or saline (n=73) in a double-masked fashion. Here we calculate the percentage of each treatment group that experienced a clinically relevant improvement as defined by previous studies as well as present what the participants of our study defined as small, medium, and large analgesic improvements using the 7-point ordinal Patient Global Impression of Change scale.
Among patients who were given a 6-day ropivacaine infusion, 57% experienced at least a 2-point improvement on the 11-point numeric rating scale in their average and worst phantom pain 4 weeks postbaseline as compared with 26% (p<0.001) for average and 25% (p<0.001) for worst pain in patients given a placebo infusion. At 4 weeks, the percentage of participants rating their pain as improved was 53% for the active vs 30% for the placebo groups (95% CI 1.7 (1.1, 2.7), p0.008). For all patients combined, the median (IQR) phantom pain Numeric Rating Scale improvements at 4 weeks considered small, medium, and large were 2 (0-2), 3 (2-5), and 5 (3-7), respectively. The median improvements in the Brief Pain Inventory interference subscale (0-70) associated with small, medium, and large analgesic changes were 8 (1-18), 22 (14-31), and 39 (26-47).
Among patients with postamputation phantom pain, a continuous peripheral nerve block more than doubles the chance of a clinically relevant improvement in pain intensity. Amputees with phantom and/or residual limb pain rate analgesic improvements as clinically relevant similarly to other chronic pain etiologies, although their smallest relevant improvement in the Brief Pain Inventory was significantly larger than previously published values.
NCT01824082.
我们之前报道过，6 天连续外周神经阻滞可减轻截肢后已形成的幻肢痛。为了向患者和医务人员提供最佳治疗决策所需的信息，我们重新分析了这些数据，并以更以患者为中心的格式呈现结果。我们还提供了患者定义的临床相关获益信息，以方便评估现有研究并指导未来的试验设计。
原始试验招募了有肢体截肢和幻肢痛的参与者，他们被随机分配接受为期 6 天的连续外周神经阻滞，罗哌卡因（n=71）或生理盐水（n=73），采用双盲法。在这里，我们计算了每个治疗组经历临床相关改善的百分比，该定义是根据之前的研究确定的，我们还使用 7 分制患者整体变化印象量表呈现了我们研究中的参与者所定义的小、中、大镇痛改善。
与接受安慰剂输注的患者相比，接受 6 天罗哌卡因输注的患者在基线后 4 周时，其平均和最差幻肢痛的数字评分量表（numeric rating scale，NRS）平均疼痛改善了 2 分，有 57%，而最差疼痛改善了 2 分，有 25%（p<0.001）。在 4 周时，接受主动治疗的参与者中有 53%的人表示疼痛有所改善，而接受安慰剂治疗的参与者有 30%（95%CI 1.7（1.1，2.7），p<0.008）。对于所有患者，4 周时幻肢痛 NRS 改善的中位数（IQR）为小、中、大分别为 2（0-2）、3（2-5）和 5（3-7）。与小、中、大镇痛变化相关的简明疼痛量表（brief pain inventory，BPI）干扰子量表（0-70）的中位数改善分别为 8（1-18）、22（14-31）和 39（26-47）。
在截肢后有幻肢痛的患者中，连续外周神经阻滞使疼痛强度的临床相关改善的机会增加了一倍以上。有幻肢痛和/或残肢痛的截肢患者对镇痛改善的评估与其他慢性疼痛病因相似，尽管他们的简明疼痛量表的最小相关改善明显大于之前发表的值。
NCT01824082。
