Treatment of Canine Atlantoaxial Subluxation with a Modified Cervical Distraction-Stabilization Technique and Clinical Outcomes.

Abstract

Atlantoaxial subluxation (AAS) is a neurosurgical condition caused by joint hyperflexion and is characterized by the development of compressive cervical myelopathy. Various ventral fixation techniques have been described to permanently reduce the subluxation by long-term stabilization of the atlantoaxial joint. However, the rate of complications related to implant failure with these techniques remains high. The aim of this study was to describe a cervical distraction-stabilization technique using screws and PMMA to treat AAS and evaluate the clinical outcomes based on neurological and radiographic follow-up. Magnetic resonance imaging (MRI) was performed to confirm the diagnosis of AAS and identify any associated intraparenchymal lesions. Computed tomography (CT) scans were performed for surgical planning. No complications resulting in irreversible damage, surgical revision, or euthanasia protocol were observed. In the immediate postoperative period, the neurological scores showed an improvement of approximately two points from the preoperative values in all subjects. At the 6-month neurological examination (medium-term follow-up), 93% (13/14) of the dogs showed normal neurological function with no signs of pain. Based on clinical follow-up data, the cervical distraction-stabilization technique described in this study appears to be a valuable surgical alternative to treat AAS in toy-breed dogs.