Explant of a Chronic Atlantoaxial Implant Infection in a Dog

An 11-year-old male neutered Yorkshire Terrier was presented with a cervical mass that developed a draining tract. Aside from the dysphagia reported by the owner, his neurologic exam was normal. Three years prior, the patient was diagnosed with an atlantoaxial subluxation that was ventrally stabilized with polymethylmethacrylate (PMMA) and self-tapping titanium screws. There were no postoperative complications until presenting with the cervical mass and dysphagia. Computerized tomography (CT) of the cervical spine confirmed caudal migration of the PMMA and screws with an abscess surrounding the implant. A surgical explant of the PMMA and screws was performed without complication. The atlantoaxial joint remained normally aligned on postoperative radiographs. Cultures of the implant grew Streptococcus bovis. He was treated with cephalexin (22 mg/kg PO BID) for 30 days. At the time of his one-month recheck, he was swallowing normally with no neurologic deficits. He remains normal at the time of this report (17 months later). This case reports a successful explant of a chronic atlantoaxial implant infection.