Partial ostectomy of the dens to correct atlantoaxial subluxation in a pony.

The research paper describes a successful surgical procedure implemented on a pony suffering from subluxation, or dislocation, of the atlantoaxial articulation (the joint between the first two vertebrae of the spine, right at the neck). The researchers were able to correct this issue by performing a partial ostectomy, or surgical removal of the bone, on the dens of the axis (a part of the spine) to realign the joint.

Background

• This case study looks at a four-year-old Welsh Section B pony gelding, which suffered from atlantoaxial subluxation. The condition involves the dislocation or slippage of the joint between the atlas (first cervical vertebra) and the axis (second cervical vertebra), which can cause discomfort and difficulty in moving the neck and head, and even lead to partial paralysis.
• Treatment usually involves a “closed reduction” method, which is a non-surgical intervention. However, in this case, the condition couldn’t be corrected by this method, prompting the veterinary surgeons to seek a surgical alternative.

Procedure

• The surgical technique used was a partial ostectomy of the dens of the axis. The dens is a bony projection rising vertically from the second cervical vertebra, around which the atlas rotates. By removing part of this structure, the surgeons were able to realign the joint.
• This was performed through a ventral (or front-side) approach, allowing for an adequate visualization of the area of interest and minimising the risk of damaging surrounding structures.

Outcome and Follow-up

• Post-surgery, the pony had an uneventful recovery and exhibited no neurologic deficits. It was noted that the neck stiffness and ataxia (uncoordinated movements) were resolved.
• Radiographic examinations (x-rays) taken 5 days and 6 months postoperatively displayed stabilisation of the atlantoaxial joint and a normalized position of the dens of the axis.

Conclusion

• The research asserts that a ventral approach to partial ostectomy can be effectively used to treat atlantoaxial subluxation, especially in cases where non-surgical treatments are unsuccessful.