Atlantoaxial Instability

Question 1

Sanchez-Masian, VCOT, 2014:
Toy breed dogs <2kg treated with a dorsal technique

1. % that achieved clinical improvement?
2. What sized dog is most appropriate for dorsal stabilization?

Answer 1

Sanchez-Masian, VCOT, 2014:

1. 93% achieved clinical improvement
2. Dogs <1.5kg as 75% of the cases that required surgical revision were >1.5kg

Question 2

Riedinger, Vet Surg, 2015:
Ventral transarticular lag screw fixation vs dorsal AA instability clamp vs ventral AA instability hook plate

Which procedure(s) provided the greatest reduction in ROM?

Answer 2

Riedinger, Vet Surg, 2015:

Both ventral techniques

Question 3

Steele, Vet Surg, 2016:
Screw and PMMA constructs for AA fixation

% of adverse events?

Answer 3

Steele, Vet Surg, 2016:

40%

Question 4

Schneider, VCOT, 2017:

Incidence of C2-3 anomalies in dogs with and without AAI?

Answer 4

Schneider, VCOT, 2017:

38% of dogs with AAI vs 12% of dogs without AAI

Question 5

Leblond, VCOT, 2017:

Safety of implant placement is optimized by limiting implant diameter to what size in toy breed dogs?

Answer 5

Leblond, VCOT, 2017:

1.5mm

Question 6

Cummings, VRU, 2018:

What degree of C1-2 overlap is strongly supportive of AAI?

Answer 6

Cummings, VRU, 2018:

C1-2 overlap of +1.55mm or less is strongly supportive, and overlap of less than -3.77mm is diagnostic for AAI

Question 7

Leblond, VCOT, 2018:
Transarticular fixation using 2 screws vs multi-implant construct using 5 or 6 screws

1. Which screw(s) were the most successfully placed?
2. Which screw(s) were the most challenging to place?
3. Which constructs were more prone to failure?

Answer 7

Leblond, VCOT, 2018:

1. C2 pedicle screws in the 6-screw construct, but these screws would also inevitably result in vertebral artery injury
2. Monocortical screws in the C2 caudal vertebral body
3. The constructs using 2 screws were more prone to failure

Question 8

Hansen, JVECC, 2019:
Traumatic AA subluxation

1. In what % of cases did CT or MRI provide additional information regarding further injuries?
2. Most common location for cervical vertebral fractures?

Answer 8

Hansen, JVECC, 2019:

1. 88%
2. C2 body