Objective—To identify risk factors for successful surgical
management of dogs with atlantoaxial subluxation
Animals—46 dogs managed surgically for AAS.
Procedure—Age at onset of clinical abnormalities,
duration of clinical abnormalities prior to surgery,
radiographic appearance of the dens, type (dorsal or
ventral procedure) and number (1 or 2) of surgeries
performed, grade of postoperative atlantoaxial joint
reduction, and neurologic status prior to surgery (preoperative),
when dogs were discharged from the hospital
(postoperative), and during a follow-up evaluation
(final) were obtained from the dogs' medical records.
Risk factors for surgical success and degree of neurologic
improvement were identified and analyzed for
Results—Age at onset of clinical abnormalities ≤ 24
months was significantly associated with greater
odds of a successful first surgery and final outcome
and a lower postoperative neurologic grade. Duration
of clinical abnormalities ≤ 10 months was significantly
associated with greater odds of a successful final
outcome and a lower final neurologic grade. A preoperative
neurologic grade of 1 or 2 was significantly
associated with a lower final neurologic grade.
Potential risk factors that did not affect odds of a successful
outcome included type of surgery performed,
grade of atlantoaxial joint reduction, radiographic
appearance of the dens, or need for a second surgery.
Conclusions and Clinical Relevance—Age at onset
of clinical abnormalities, duration of clinical abnormalities
prior to surgery, and preoperative neurologic status
are risk factors for success of surgical management
of AAS in dogs. (J Am Vet Med Assoc 2000;