Successful Management of and Recovery from Multiple Cranial Nerve Palsies following Surgical Ventral Stabilization in a Dog with Atlantoaxial Subluxation

SIMPLE SUMMARY: Ventral-approach techniques have been broadly employed for the surgical stabilization of atlantoaxial subluxation. The postoperative complications following ventral stabilization may include upper-respiratory, pharyngeal, and laryngeal dysfunction due to inadvertent damage to adjacent structures, such as the larynx, trachea, and neuronal tissues. The exact causes and management methods for postoperative complications after ventral stabilization have not yet been fully elucidated. Implanted polymethylmethacrylate cement can cause multiple cranial nerve palsies affecting the adjacent nuclei of the cranial nerves or their peripheral roots or axons. Early revision surgery may promote the full recovery of the affected neurological dysfunctions. Clinicians should consider cranial nerve palsies as major complications of ventral stabilization surgery in patients with atlantoaxial subluxation and be cautious about the volume and extent of polymethylmethacrylate during ventral stabilization, especially in very-small-breed dogs. ABSTRACT: A 4-year-old spayed female miniature poodle dog presented with a 1-week history of acute tetraparesis. A neurological examination revealed severe neck pain and non-ambulatory tetraparesis. Computed tomography and magnetic resonance imaging showed hypoplastic dens with moderate compression of the spinal cord at C1–C2. The atlantoaxial subluxation (AAS) was surgically stabilized using ventral pins and polymethylmethacrylate (PMMA) cement. On the second postoperative day, the patient showed significant dyspnea, and aspiration pneumonia was identified on radiography. The patient exhibited dysphagia with abnormal food prehension and an inability to protrude the tongue, with no gag reflex. We tentatively diagnosed the patient with multiple cranial nerve (CN) palsies involving the 9th, 10th, and 12th CNs following surgical ventral stabilization. The protruding cranial part of the implanted PMMA cement, which could mechanically contribute to the corresponding CNs dysfunction, was surgically removed. The symptoms gradually improved, and the patient showed normal tongue movement 1 month after revision surgery. In conclusion, we report herein a canine case of multiple CN palsies following ventral stabilization surgery for AAS. The experience gained from this case suggests an optimized management plan for postoperative neurological complications associated with ventral stabilization.