Division of Neurosurgery, University of British Columbia, Vancouver, British Columbia, Canada.
Division of Neurosurgery, Hamad General Hospital, Doha, Qatar.
Stereotact Funct Neurosurg. 2023;101(1):68-71. doi: 10.1159/000528094. Epub 2022 Dec 29.
The vagus nerve has motor, sensory, and parasympathetic components. Understanding the nerve's internal anatomy, its variations, and relationship to the glossopharyngeal nerve are crucial for neurosurgeons decompressing the lower cranial nerves. We present a case report demonstrating the location of the parasympathetic fibres within the vagus nerve rootlets. A 47-year-old woman presented with a 1-year history of medically refractory left-sided glossopharyngeal neuralgia and a more recent history of left-sided hemi-laryngopharyngeal spasm. magnetic resonance imaging showed her left posterior inferior cerebellar artery distorting the lower cranial nerves on the affected left side. The patient consented to microvascular decompression of the lower cranial nerves with possible sectioning of the glossopharyngeal and upper sensory rootlets of the vagus nerve. During surgery, electrical stimulation of the most caudal rootlet of the vagus nerve triggered profound bradycardia. None of the more rostral rootlets had a similar parasympathetic response. This case is the first demonstration, to our knowledge, of the location of the cardiac parasympathetic fibres within the human vagus nerve rootlets. This new understanding of the vagus nerve rootlets' distribution of pure sensory (most rostral), motor/sensory (more caudal), and parasympathetic (most caudal) fibres may lead to a better understanding and diagnosis of the vagal rhizopathies. Approximately 20% of patients with glossopharyngeal neuralgia also have paroxysmal cough. This could be due to the anatomical juxtaposition of the IXth cranial nerve with the rostral vagal rootlets with pure sensory fibres (which mediate a tickling sensation in the lungs). A subgroup of patients with glossopharyngeal neuralgia have neuralgia-induced syncope. The cause of this rare condition, "vago-glossopharyngeal neuralgia," has been debated since it was first described by Riley in 1942. Our case supports the theory that this neuralgia-induced bradycardia is reflexively mediated through the brainstem with afferent impulses in the IXth and efferent impulses in the Xth cranial nerve. The rarer co-occurrence of glossopharyngeal neuralgia with hemi-laryngopharyngeal spasm (as seen in this case) may be explained by the proximity of the IXth nerve with the more caudal vagus rootlets which have motor (and probably sensory) supply to the throat. Finally, if there is a vagal rhizopathy related to compression of its parasympathetic fibres, one would expect it to be at the most caudal rootlet of the vagus nerve.
迷走神经具有运动、感觉和副交感成分。了解神经的内部解剖结构、变异及其与舌咽神经的关系，对神经外科医生减压颅神经非常重要。我们报告了一例展示迷走神经根内副交感纤维位置的病例报告。一名 47 岁女性，有 1 年左侧舌咽神经痛病史，近期出现左侧半喉咽痉挛。磁共振成像显示她的左后下小脑动脉在受影响的左侧扭曲颅神经。患者同意进行颅神经微血管减压术，可能会切断舌咽神经和迷走神经的上感觉神经根。手术过程中，刺激迷走神经最尾端的神经根会引发明显的心动过缓。没有任何更接近颅端的神经根有类似的副交感反应。这是我们所知的首例在人体迷走神经根内展示心内副交感纤维位置的病例。对迷走神经根内纯感觉（最颅端）、运动/感觉（更尾端）和副交感（最尾端）纤维分布的新认识，可能会导致对迷走神经根病变的更好理解和诊断。约 20%的舌咽神经痛患者也有阵发性咳嗽。这可能是由于第 9 颅神经与含有纯感觉纤维的迷走神经根的颅端毗邻（这些纤维在肺部引起瘙痒感）。一组舌咽神经痛患者有神经痛引起的晕厥。自 1942 年 Riley 首次描述以来，这种罕见疾病“迷走-舌咽神经痛”的病因一直存在争议。我们的病例支持这样一种理论，即这种神经痛引起的心动过缓是通过脑干反射性介导的，传入冲动在第 9 颅神经，传出冲动在第 10 颅神经。如本例所见，舌咽神经痛伴半喉咽痉挛更为罕见，这可能是由于第 9 颅神经与更尾端的迷走神经根毗邻，而后者对喉咙有运动（可能还有感觉）供应。最后，如果有与迷走神经副交感纤维受压相关的迷走神经根病变，人们会预期它位于迷走神经的最尾端神经根。
