The weepy cry: short neural signal bursts in intraoperative neuromonitoring
Purpose: This study aimed to establish an in-vitro alternative to existing in-vivo systems to analyze nerve dysfunction using continuous neuromonitoring (C-IONM). Methods: Three hundred sixty-three recurrent laryngeal nerves (RLN) (N(pigs) = 304, N(cattle) = 59) from food industry cadavers were expo...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
22 March 2024
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| In: |
Langenbeck's archives of surgery
Year: 2024, Volume: 409, Pages: 1-10 |
| ISSN: | 1435-2451 |
| DOI: | 10.1007/s00423-024-03240-z |
| Online Access: | Verlag, kostenfrei, Volltext: https://doi.org/10.1007/s00423-024-03240-z
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| Author Notes: | Philipp C.B. Munk, Mick E. Merkelbach, Wolfram Lamadé |
| Summary: | Purpose: This study aimed to establish an in-vitro alternative to existing in-vivo systems to analyze nerve dysfunction using continuous neuromonitoring (C-IONM). Methods: Three hundred sixty-three recurrent laryngeal nerves (RLN) (N(pigs) = 304, N(cattle) = 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%. Results: 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. Conclusion: 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. |
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| Item Description: | Gesehen am 15.07.2024 |
| Physical Description: | Online Resource |
| ISSN: | 1435-2451 |
| DOI: | 10.1007/s00423-024-03240-z |