Computed tomographic myelography of the cranial cervical spine in Warmblood horses with no spinal pathology-Inter- and intravertebral ratios and distribution of contrast columns in neutral and flexed cervical spine.
Authors: Hellige Maren, Schröder Caroline, Seehusen Frauke, Cavalleri Jessika-M, Rohn Karl, Stadler Peter, Geburek Florian
Journal: Equine veterinary journal
Summary
# Editorial Summary Understanding normal myelographic findings across different cervical positions is essential for accurately interpreting diagnostic imaging in horses with suspected cervical myelopathy, yet little data exists on how contrast distribution varies between neutral and flexed positions in unaffected animals. Hellige and colleagues performed both radiographic and computed tomographic myelography on 13 neurologically normal Warmblood horses in neutral and flexed (24°) cervical positions, measuring spinal cord diameter and dorsal and ventral contrast column heights at C3–C4, with histological confirmation of absence of pathology. Cervical flexion significantly reduced spinal cord diameter by approximately 1–1.5 mm at both C3–C4 and C4–C5 levels, whilst dorsal contrast columns decreased by roughly 1.5–2 mm and ventral columns became nearly obliterated at some intervertebral spaces—changes that were consistent across both imaging modalities. These findings provide critical baseline reference values that veterinarians and clinicians must consider when evaluating myelographic studies in symptomatic horses, as flexion-induced compression of normal neural structures could otherwise be misinterpreted as pathological narrowing; however, the small sample size and lack of radiographic calibration warrant cautious application pending larger confirmatory studies.
Read the full abstract on PubMed
Practical Takeaways
- •Normal cervical flexion naturally compresses the spinal cord and contrast columns; clinicians must account for this when interpreting myelographs, as flexion-related compression should not be misinterpreted as pathological stenosis
- •Ventral contrast column essentially disappears during cervical flexion in normal horses, so absence of ventral contrast in flexed positions is not necessarily pathological
- •Comparative imaging in both neutral and flexed positions may improve diagnostic accuracy for detecting clinically significant extradural compressions in horses with cervical ataxia
Key Findings
- •Cervical spine flexion at 24° significantly reduced spinal cord diameter in CTM at C3-C4 (9.2±1.1 mm to 8.0±1.4 mm, p=0.02) and C4-C5 (9.2±1.3 mm to 7.7±1.7 mm, p=0.007)
- •Flexion significantly decreased dorsal contrast column height in both RxM and CTM at C3-C4 (RxM: 10.2±1.9 to 8.5±2.1 mm, p=0.005; CTM: 8.8±1.4 to 7.2±2.0 mm, p=0.004)
- •Ventral contrast column was nearly eliminated at C4-C5 during flexion in both modalities (RxM: 2.7±1.3 to 0.9±0.7 mm; CTM: 2.2±1.2 to 0.0±0.1 mm, both p<0.001)
- •Findings establish normal baseline measurements for contrast distribution in Warmbloods without spinal pathology, essential for interpreting myelographic abnormalities in affected horses