Current dorsal myelographic column and dural diameter reduction rules do not apply at the cervicothoracic junction in horses.

The research article explores the inapplicability of current rules for measuring dorsal myelographic column and dural diameter reduction at the cervicothoracic junction in horses. This study finds that alternative criteria should be used to better assess possible spinal cord compression in this area.

Understanding the Context and Hypothesis

• The authors observed that past myelographic studies did not report on the cervicothoracic (C7-T1) junction in horses, an area where they suspected the existing rules for detecting spinal cord compression might fall short.
• With the use of modern digital radiographic equipment, the researchers proposed a theory that the usual criteria (a 50% reduction in the dorsal myelographic column or a 20% reduction of the dural diameter) used to indicate spinal cord compression might not apply at C7-T1.

Method and Findings

• The researchers conducted a myelographic study on 12 healthy, neurologically normal horses and found that, according to traditional criteria, 8 out of the 12 horses would appear to have signs of spinal cord compression at C7-T1. This indicated that the current criteria may yield false positive results at this particular junction.
• They accumulated data on the dorsal myelographic column reduction and the dural diameter reduction at the respective sites and discovered that the reduction at C7-T1 was significantly higher. This finding further supported their theory that current standards might yield a false diagnosis of spinal cord compression in this area.

Interpretation and Conclusion

• The team concluded that the observed reduction in the dorsal myelographic column and dural diameter at C7-T1 was due to larger intravertebral measurements at C7 as opposed to smaller measurements at C7-T1. These findings again suggested that the current criteria might not be valid for diagnoses in this part of the spine.
• In light of their findings, they propose a new set of criteria for this region: reduction of the dorsal myelographic column by 60% or the dural diameter by 30%. They suggest these adjustments would avoid a high rate of false positives for spinal cord compression at C7-T1. This change could help better diagnose and treat cervical stenotic myelopathy, a condition characterized by the narrowing of the spinal canal in the neck.