Objective

Repetitive transcranial magnetic stimulation (rTMS) may be a relevant method to assist postoperative pain. However, studies to date have only used conventional 10 Hz rTMS and targeted the DLPFC for postoperative pain. A more recent form of rTMS, termed intermittent Theta Burst Stimulation (iTBS), enables to increase cortical excitability in a short period of time. This preliminary double-blind, randomised, sham controlled study was designed to evaluate the efficacy of iTBS in postoperative care across two distinct stimulation targets.

Methods

A group of 45 patients post laparoscopic surgery were randomised to receive a single session of iTBS over either the dorsolateral prefrontal cortex (DLPFC), primary motor cortex (M1), or Sham stimulation (1:1:1 ratio). Outcome measurements were number of pump attempts, total anaesthetic volume used, and self-rated pain experience, assessed at 1 hour, 6 hours, 24 hours, and 48 hours post stimulation. All randomised patients were analysed (n = 15 in each group).

Results

Compared to Sham stimulation, DLPFC-iTBS reduced pump attempts at 6 (DLPFC = 0.73 ± 0.88, Sham = 2.36 ± 1.65, P = 0.031), 24 (DLPFC = 1.40 ± 1.24, Sham = 5.03 ± 3.87, P = 0.008), and 48 (DLPFC = 1.47 ± 1.41, Sham = 5.87 ± 4.34, P = 0.014) hours post-surgery, whereby M1 stimulation had no effect. No group effect was observed on total anaesthetics, which was mainly provided through the continuous administration of opioids at a set speed for each group. There was also no group or interaction effect on pain ratings. Pump attempts were positively associated with pain ratings in the DLPFC (r = 0.59, P = 0.02) and M1 (r = 0.56, P = 0.03) stimulation.

Conclusions

Our findings show that iTBS to the DLPFC reduces pump attempts for additional anaesthetics following a laparoscopic surgery. However, reduced pump attempts by DLPFC stimulation did not translate into a significantly smaller volume of total anaesthetic, due to the continuous administration of opioids at a set speed for each group.

Significance

Our findings therefore provide preliminary evidence for iTBS targeting the DLPFC to be used to improve postoperative pain management.

中文翻译：

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θ波刺激对术后疼痛的镇痛效果

客观的

重复经颅磁刺激 (rTMS) 可能是缓解术后疼痛的相关方法。然而，迄今为止的研究仅使用传统的 10 Hz rTMS 并针对 DLPFC 治疗术后疼痛。一种更新形式的 rTMS，称为间歇性 Theta 突发刺激 (iTBS)，能够在短时间内增加皮质兴奋性。这项初步的双盲、随机、假对照研究旨在评估 iTBS 在两个不同刺激目标的术后护理中的功效。

方法

一组 45 名腹腔镜手术后的患者被随机分配到背外侧前额叶皮层 (DLPFC)、初级运动皮层 (M1) 或假刺激（1:1:1 比例）接受单次 iTBS。结果测量是在刺激后 1 小时、6 小时、24 小时和 48 小时评估的泵尝试次数、使用的总麻醉剂量和自评疼痛体验。对所有随机分组的患者进行了分析（每组 n = 15）。

结果

与假刺激相比，DLPFC-iTBS 减少了 6 次泵尝试（DLPFC = 0.73 ± 0.88，假 = 2.36 ± 1.65，P = 0.031），24（DLPFC = 1.40 ± 1.24，假 = 5.03 ±  3.87，P  = 0.008），和 48 (DLPFC = 1.47 ± 1.41, Sham = 5.87 ± 4.34, P  = 0.014) 小时手术后，其中 M1 刺激没有效果。未观察到对全麻的组效应，这主要是通过以每组设定的速度持续给予阿片类药物来提供的。疼痛评分也没有群体或相互作用的影响。泵尝试与 DLPFC（r  = 0.59，P  = 0.02）和 M1（r  = 0.56，P  = 0.03）刺激的疼痛等级呈正相关。

结论

我们的研究结果表明，DLPFC 的 iTBS 减少了腹腔镜手术后对额外麻醉剂的泵尝试。然而，由于每组都以设定的速度连续施用阿片类药物，因此通过 DLPFC 刺激减少的泵尝试并未转化为显着更小的总麻醉量。

意义

因此，我们的研究结果为靶向 DLPFC 的 iTBS 用于改善术后疼痛管理提供了初步证据。