Surgical decompression for traumatic atlantoaxial subluxation in a weanling filly.

This study involves a young female horse (a filly) that suffered from atlantoaxial subluxation, a condition involving instability of the top two vertebrae of the neck, leading to neurological issues like ataxia. Upon diagnosis using radiographic images, a surgical procedure known as hemilaminectomy was carried out to relieve pressure on the spinal cord. No efforts were made to stabilize the region post-surgery, and though initial recovery seemed promising, the filly’s unexpected death prevented further analysis of the intervention’s effectiveness.

Research Context and Subject

• The subject of this research was a weanling filly, a young female horse, which suffered from atlantoaxial subluxation.
• Atlantoaxial subluxation refers to the dislocation or malalignment of the first and second cervical vertebrae, resulting from ligamentous injury or a congenital malformation.
• The condition is serious as it can cause significant neurological deficits and pain due to the compression of the spinal cord. In this case, the filly exhibited symptoms of ataxia (loss of full control of bodily movements) and unusual sounds (crepitation) from the neck.

Diagnosis

• Radiography was used for the diagnosis of this condition in the filly. This involved the use of X-rays to view the interior structures of the horse.
• The diagnostic criteria used are based on those valid in other species: increased gap between the atlas (the first cervical vertebra) and the axis (the second cervical vertebra), as well as an increased distance between the dens and the floor of the atlas.

Treatment Procedure

• Once diagnosed, a surgical procedure called hemilaminectomy was implemented. This involves removing one side of the vertebral arch to relieve pressure or reduce the size of an existing lesion on the spinal cord.
• An important note is that no attempts were made to stabilize the atlantoaxial region after the operation. Post-surgical stabilization is sometimes performed to prevent further subluxation and protect the fragile spinal cord in the region from further trauma.

Result and Conclusion

• The filly showed positive initial responses to the operation, suggesting that the surgical decompression could have been an effective treatment for the trauma-induced subluxation.
• However, the untimely death of the filly prevented further assessment of the long-term effectiveness of the procedure, providing an inconclusive end to the study.