Neurogenic irritable bowel syndrome? Long-term resolution of chronic gastrointestinal stress following vagus nerve microvascular decompression: illustrative case

BACKGROUND: Microvascular decompression (MVD) is a well-established treatment for compressive cranial neuralgias such as trigeminal neuralgia and hemifacial spasm. The vagus nerve (cranial nerve [CN] X), with its extensive parasympathetic innervation to the gastrointestinal (GI) system, has less clearly defined neuropathic symptomatology, and MVD of CN X has only been reported once. The authors report a unique case of treatment-refractory GI distress that resolved completely following CN X MVD. OBSERVATIONS: A 32-year-old male with a 13-year history of hemifacial spasm also experienced chronic, debilitating GI distress characterized by sudden, painful abdominal cramping and diarrhea. Despite extensive workup, including three colonoscopies, no clear etiology was found. During MVD for his facial nerve, a large vertebral artery loop was incidentally found significantly displacing CN X. Both nerves were decompressed. Both the patient's hemifacial spasms and GI symptoms resolved immediately, and this has persisted for more than 5 years of follow-up. LESSONS: While vagal injury (including intentionally via vagotomy) results in gastroparesis, the authors propose that chronic CN X compression may induce a "hyperactive rhizopathy" resulting in symptoms of overactive peristalsis. CN X compression may be an underrecognized, reversible etiology of chronic GI distress, and clinicians should consider the possibility of neurovascular conflict in this patient population. https://thejns.org/doi/10.3171/CASE2688.