Ultrasonographic assessment of the atlanto-occipital space in healthy Thoroughbred foals and Thoroughbred foals with neonatal maladjustment syndrome.
Authors: Mackenzie C J, Haggett E F, Pinchbeck G L, Marr C M
Journal: Veterinary journal (London, England : 1997)
Summary
Neonatal maladjustment syndrome (NMS) in foals remains challenging to diagnose definitively, prompting investigation into whether ultrasound examination of the atlanto-occipital space might offer a non-invasive diagnostic aid in the critical first days of life. Mackenzie and colleagues performed transverse and longitudinal ultrasound scans of the AO region in 38 healthy Thoroughbred foals and 28 foals diagnosed with NMS (all ≤4 days old), measuring spinal cord dimensions, cross-sectional area, and vascular structures. Several significant differences emerged between groups: healthy foals exhibited larger spinal cord height, width and cross-sectional area, whilst foals with NMS showed smaller values across these parameters; notably, the ratios of spinal canal to cord width and area were significantly reduced in healthy foals compared to affected foals, suggesting relative cord swelling or canal narrowing in NMS cases. The ventral spinal artery diameter on longitudinal imaging was also notably smaller in NMS foals, though spinal canal measurements themselves did not differ significantly between groups. For practitioners managing neonatal foals, these findings suggest ultrasonographic assessment of AO space morphology warrants further investigation as a potential objective diagnostic tool, though additional work is needed to establish clinical utility and determine whether observed changes are causative, consequential, or coincidental to NMS presentation.
Read the full abstract on PubMed
Practical Takeaways
- •Ultrasonography of the atlanto-occipital space may offer a non-invasive diagnostic tool for identifying neonatal maladjustment syndrome in foals ≤4 days old
- •Spinal cord measurements (height, width, and cross-sectional area) appear more diagnostically useful than spinal canal measurements for differentiating NMS from healthy foals
- •Further clinical validation studies are needed before recommending routine use of this technique in practice
Key Findings
- •Spinal cord height, width, and cross-sectional area were significantly smaller in NMS foals compared to healthy foals (P=0.001 to P<0.001)
- •Ratios of spinal canal to cord width and cross-sectional area were significantly smaller in healthy foals than NMS foals (P<0.001)
- •Dorsoventral diameter of the ventral spinal artery was significantly smaller in NMS foals on longitudinal imaging
- •Spinal canal variables showed no significant differences between healthy and NMS foals