Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Site Tenon, Service de Chirurgie Thoracique, F-75013 Paris, France.
Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005 Paris, France; AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Site Pitié-Salpêtrière, Service de Réhabilitation Respiratoire et Neuro-Respiratoire (Département R3S), F-75013 Paris, France.
Ann Anat. 2022 Jan;239:151835. doi: 10.1016/j.aanat.2021.151835. Epub 2021 Sep 23.
Diaphragm pacing allows certain ventilator-dependent patients to achieve weaning from mechanical ventilation. The reference method consists in implanting intrathoracic contact electrodes around the phrenic nerve during video-assisted thoracic surgery, which involves time-consuming phrenic nerve dissection with a risk of nerve damage. Identifying a phrenic segment suitable for dissection-free implantation of electrodes would constitute progress.
This study characterizes a free terminal phrenic segment never fully described before. We conducted a cadaver study (n = 14) and a clinical observational study during thoracic procedures (n = 54).
A free terminal phrenic segment was observed on both sides in 100% of cases, "jumping" from the pericardium to the diaphragm and measuring 60 mm [95% confidence interval; 48-63] and 72.5 mm [65-82] (right left, respectively; p = 0.0038; cadaver study). This segment rolled up on itself at end-expiration and became unravelled and elongated with diaphragm descent (clinical study). Three categories of fat pads were defined (type 1: pericardiophrenic bundle free of surrounding fat; type 2: single fatty fringe leaving the phrenic nerve visible until diaphragmatic entry; type 3: multiple fatty fringes masking the site of penetration of the phrenic nerve) that depended on body mass index (p = 0.001, clinical study). Hematoxylin-eosin and toluidine blue staining (cadaver study) showed that all of the phrenic fibers in the distal, pre-branching part of the terminal segment were contained within a single epineurium containing a variable number of fascicles (right: 1 [95%CI 0.65-4.01]; left 5 [3.37-7.63]; p = 0.03).
Diaphragm pacing through periphrenic electrodes positioned on the terminal phrenic segment should be tested.
膈神经起搏可使某些依赖呼吸机的患者实现脱机。参考方法包括在胸腔镜辅助手术中在膈神经周围植入胸腔内接触电极，但这种方法需要耗时的膈神经解剖，存在神经损伤的风险。如果能找到一段适合无神经解剖电极植入的膈神经节段，将会是一个进步。
本研究对一段以前从未完整描述过的游离终末膈神经节段进行了特征描述。我们进行了尸体研究（n=14）和胸腔镜手术期间的临床观察研究（n=54）。
在所有病例中，100%观察到双侧游离终末膈神经节段，该节段从心包“跳跃”至膈肌，长度为 60mm[95%置信区间；48-63]和 72.5mm[65-82]（右侧和左侧，分别；p=0.0038；尸体研究）。该节段在呼气末时自行缠绕，随膈肌下降而展开和延长（临床研究）。定义了三种脂肪垫类型（1 型：膈神经周围无包裹脂肪的膈心包束；2 型：单条脂肪边缘，可在膈神经进入前看到膈神经；3 型：多条脂肪边缘，掩盖膈神经进入部位），该类型取决于体重指数（p=0.001，临床研究）。苏木精-伊红和甲苯胺蓝染色（尸体研究）显示，游离终末段的远端、分支前部分的所有膈神经纤维都包含在单个神经外膜内，该神经外膜包含数量不等的神经束（右侧：1[95%置信区间 0.65-4.01]；左侧：5[3.37-7.63]；p=0.03）。
应测试通过置于终末膈神经段周围的膈神经周围电极进行膈神经起搏。
