Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany.
BG Klinikum Murnau, Murnau, Germany.
Langenbecks Arch Surg. 2024 Mar 22;409(1):102. doi: 10.1007/s00423-024-03240-z.
This study aimed to establish an in-vitro alternative to existing in-vivo systems to analyze nerve dysfunction using continuous neuromonitoring (C-IONM).
Three hundred sixty-three recurrent laryngeal nerves (RLN) (N = 304, N = 59) from food industry cadavers were exposed by microsurgical dissection following euthanasia. After rinsing with Ringer's lactate, they were tempered at 22 °C. Signal evaluation using C-IONM was performed for 10 min at 2 min intervals, and traction forces of up to 2N were applied for a median time of 60 s. Based on their post-traumatic electrophysiological response, RLNs were classified into four groups: Group A: Amplitude ≥ 100%, Group B: loss of function (LOS) 0-25%, Group C: ≥ 25-50%, and Group D: > 50%.
A viable in-vitro neuromonitoring system was established. The median post-traumatic amplitudes were 112%, 88%, 59%, and 9% in groups A, B, C, and D, respectively. A time-dependent further dynamic LOS was observed during the 10 min after cessation of strain. Surprisingly, following initial post-traumatic hyperconductivity, complete LOS occurred in up to 20% of the nerves in group A. The critical threshold for triggering LOS was 2N in all four groups, resulting in immediate paralysis of up to 51.4% of the nerves studied.
Consistent with in-vivo studies, RLN exhibit significant intrinsic electrophysiological variability in response to tensile forces. Moreover, nerve damage progresses even after the complete cessation of strain. Up to 20% of nerves with transiently increased post-traumatic amplitudes above 100% developed complete LOS, which we termed the "weepy cry." This time-delayed response must be considered during the interpretation of C-IONM signals.
本研究旨在建立一种体外替代现有体内系统，使用连续神经监测（C-IONM）分析神经功能障碍。
在安乐死后，通过显微解剖暴露 363 条（N=304，N=59）来自食品工业尸体的喉返神经（RLN）。用林格乳酸盐冲洗后，将其在 22°C 下调温。使用 C-IONM 进行 10 分钟的信号评估，每隔 2 分钟进行一次，施加的牵引力高达 2N，持续时间中位数为 60 秒。根据其创伤后电生理反应，RLN 分为四组：A 组：幅度≥100%；B 组：功能丧失（LOS）0-25%；C 组：≥25-50%；D 组：>50%。
建立了一种可行的体外神经监测系统。A、B、C 和 D 组的创伤后中位数幅度分别为 112%、88%、59%和 9%。在应变停止后 10 分钟内，观察到与时间相关的进一步动态 LOS。令人惊讶的是，在最初的创伤后过度传导后，高达 20%的 A 组神经出现完全 LOS。在所有四组中，触发 LOS 的临界阈值均为 2N，导致研究中多达 51.4%的神经立即瘫痪。
与体内研究一致，RLN 在响应拉伸力时表现出显著的固有电生理变异性。此外，即使完全停止应变，神经损伤仍会继续进展。高达 20%的神经在创伤后幅度暂时增加到 100%以上，会出现完全 LOS，我们称之为“哭泣声”。在解释 C-IONM 信号时，必须考虑这种延迟反应。
