Ex Vivo Computed Tomographic Evaluation of Morphology Variations in Equine Cervical Vertebrae

Abstract

Diagnostic imaging is one of the pillars in the clinical workup of horses with clinical signs of cervical spinal disease. An improved awareness of morphologic variations in equine cervical vertebrae would be helpful for interpreting findings. The aim of this anatomic study was to describe CT variations in left-right symmetry and morphology of the cervical and cervicothoracic vertebrae in a sample of horses. Postmortem CT examinations of the cervical spine for horses without congenital growth disorders were prospectively and retrospectively recruited. A total of 78 horses (27 foals, 51 mature horses) were evaluated. Twenty-six horses (33.3%) had homologous changes in which a transposition of the caudal part of the transverse process (caudal ventral tubercle) of C6 toward the ventral aspect of the transverse process of C7 was present (n = 10 bilateral, n = 12 unilateral left-sided, n = 4 unilateral right-sided). There was one horse with occipito-atlantal malformation, two horses with rudimentary first ribs bilaterally, and one horse with bilateral transverse processes at Th1, representing homeotic (transitional) vertebral changes. Chi-square tests identified no significant differences in the number of conformational variations between the group of mature horses with or without clinical signs (P = 0.81) or between the group of mature horses and the group of foals (P = 0.72). Findings indicated that, in this sample of horses, the most frequently identified variations were homologous variations (transposition of the caudal part of the transverse process of C6-C7) in the caudal equine cervical vertebral column. Homeotic (transitional) variations at the cervicothoracic vertebral column were less common.

Cone-beam computed tomography of the head in standing equids

“…Using the described set up and protocol, we were reliably able to obtain CBCT volume acquisitions of diagnostic quality that allowed the establishment of a radiologic diagnosis or to rule out structural changes in 73 of 75 cases (97.3%). The percentage of horses, in which no diagnosis could be established is comparable to the number reported using a conventional CT scanner with a sliding gantry, where no images of diagnostic quality could be acquired in 11 out of 114 horses [11]. However, the spectrum of established radiological diagnoses using CBCT seems to be larger enabling the diagnosis of temporohyoid-osteoarthropathy, aggressive bone lesions, suture periostitis, primary rhinitis and soft tissue abcessation beside the usual diagnoses like alveolitis with or without secondary sinusitis and fractures [11].…”

“…The percentage of horses, in which no diagnosis could be established is comparable to the number reported using a conventional CT scanner with a sliding gantry, where no images of diagnostic quality could be acquired in 11 out of 114 horses [11]. However, the spectrum of established radiological diagnoses using CBCT seems to be larger enabling the diagnosis of temporohyoid-osteoarthropathy, aggressive bone lesions, suture periostitis, primary rhinitis and soft tissue abcessation beside the usual diagnoses like alveolitis with or without secondary sinusitis and fractures [11]. In this study, the accuracy of the established diagnosis was not assessed, but we still consider the use of CBCT as a valuable imaging modality to assess equine head disorders in standing sedated equids.…”

“…Overcoming the restrictions of two-dimensional radiographic imaging, CT imaging has become the gold standard imaging modality to diagnose common disorders in the equine head and to perform pre-surgical planning. To avoid general anesthesia, CT of the head is increasingly performed with the horse in a standing position [1–4], [8–11]. …”

Equine cervical intervertebral disc degeneration is associated with location and MRI features

“…Equine vertebral morphologic variations, vertebral pathology, and their clinical manifestations have previously been described . The small group of horses in this study presented varying clinical signs related to the cervical area.…”

“…3 Equine vertebral morphologic variations, vertebral pathology, and their clinical manifestations have previously been described. 32,33 The small group of horses in this study presented varying clinical varies greatly between individuals. 20 In addition to intervertebral disc degeneration, pain also appears to correlate inconsistently with vertebral Modic changes grade 1 (bone edema and inflammation) and discal endplate lesions.…”