Multiple cervical spondylolisthesis and thoracic vertebral malformation in an 11 month-old Chilean Caballo Raza Chilena colt

Abstract

Compressive myelopathy caused by developmental cervical and thoracic malformation was diagnosed in an 11-monthold Chilean Caballo Raza Chilena colt. The patient evidenced an abnormal wide-based stance, neck muscle atrophy, upside-down neck conformation and tetra ataxia. Ataxia was exacerbated when the colt was walked down and uphill, walked with elevated head, backing and turning in tight circles. The patient showed no improvement following medical therapy, therefore, the colt was euthanised due to a poor prognosis after myelogram findings. Cervical spine malalignment (spondylolisthesis) associated with multi-level compression of the spinal cord was suspected based on cervical radiographs and myelogram findings and was confirmed postmortem. Thoracic vertebral malformation retained cartilage matrix spicules and a flare of the cranial vertebral epiphysis of the first thoracic vertebrae (T1) were also diagnosed at necropsy.

Congenital kyphoscoliosis associated with thoracic hemivertebrae in a nine-month-old Racking filly

“…In the case report published by Kothstein et al, acquired kyphosis a due to compression fractures of T14 to T18 in association with mild hindlimb ataxia was described in a 20-month-old horse (Kothstein et al, 2000). Rendle et al reported a kyphosis of the thoracolumbar spine with thoracic neurenteric cyst and butterfly vertebrae at T6 and T7 in a seven-month-old colt that suffered from very severe neurologic deficits (Dorner et al, 2022). In the presented filly here, a mild neurological deficit was observed in hindlimbs that may be due to compression and narrowing of the spinal cord at the T13.…”

“…In horses, developmental vertebral disorders, commonly cause malformations of the cervical vertebrae (de Heer & Nout, 2011;Dorner et al, 2022;Rendle et al, 2008;Unt & Piercy, 2009;Wong et al, 2005) while thoracic and lumbar vertebral malformations are infrequent (de Heer & Nout, 2011;Wong et al, 2005). Vertebral malformations can be congenital (present at birth) or acquired (later in life) (Wong et al, 2005).…”

“…The etiological factors causing vertebral malformations have not been fully explained in horses, but genetic and heredity factors, dietary imbalances, toxic factors, hormonal changes, environmental cusses, trauma, and in-utero insult may be responsible (Auer & Stick, 2018;Dorner et al, 2022;Kirkberger & Gottschalk, 1989;Kothstein et al, 2000;Unt & Piercy, 2009;Wong et al, 2005). It has been mentioned that alteration in genes expression, especially members of Hox family, may contribute to malformations of the axial skeleton and vertebrae (Unt & Piercy, 2009).…”

Congenital kyphoscoliosis associated with thoracic hemivertebrae in a 9‐month‐old Racking filly

“…In horses, developmental vertebral disorders commonly cause malformations of the cervical vertebrae (de Heer & Nout, 2011; Dorner et al, 2022; Rendle et al, 2008; Unt & Piercy, 2009; Wong et al, 2005) while thoracic and lumbar vertebral malformations are infrequent (de Heer & Nout, 2011; Wong et al, 2005). Vertebral malformations can be congenital (present at birth) or acquired (later in life; Wong et al, 2005).…”

“…The aetiological factors causing vertebral malformations have not been fully explained in horses. Still, genetic and heredity factors, dietary imbalances, toxic factors, hormonal changes, environmental causes, trauma and in‐utero insult (oxygen deficiency, increased temperature and carbon monoxide) may be responsible (Dorner et al, 2022; Fürst, 2018; Kirkberger & Gottschalk, 1989; Kothstein et al, 2000; Unt & Piercy, 2009; Witzmann et al, 2014; Wong et al, 2005). An interaction between genetic susceptibility of the developing embryo or fetus and these factors probably exists (Witzmann et al, 2014).…”