Morphometric analysis of spinal cord termination in Cavalier King Charles Spaniels

Abstract

Background There is an association between Chiari malformations, syringomyelia (CMSM) and tethered cord syndrome (TCS) in people, suggesting Cavalier King Charles Spaniels (CKCS) with CMSM could also have TCS. Currently there are no data on the position of the caudal spinal cord structures in CKCS. Objective To describe and compare location of spinal cord termination in CKCS with weight‐matched controls and to examine the relationship between SM and spinal cord termination. Animals Thirty‐nine CKCS and 33 controls with thoracolumbar MRIs; 34 of 39 CKCS also had cervical MRIs. Methods Blinded retrospective study. Spinal cord and dural sac termination were determined from T2‐weighted sagittal and transverse images and half‐Fourier acquisition single‐shot turbo spin echo sequences. Intra‐observer reliability was determined using kappa analysis. Presence of SM was compared with location of spinal cord and dural sac termination. Results Intra‐observer reliability was moderate for identifying spinal cord termination (Kappa = 0.6) and good for dural sac termination (Kappa = 0.8). The spinal cord terminated at lumbar vertebra 6 (L6) in 1, 7 (L7) in 22, and sacrum in 16 CKCS versus 9 at L6, 23 at L7, 1 at sacrum in controls. Spinal cord (P < .001) and dural sac (P = .002) termination were significantly more caudal in CKCS compared to controls. The presence of thoracolumbar SM was associated with more caudal dural sac termination in CKCS (P = .03). Conclusions and Clinical Importance The relationship between TL SM and possible spinal cord tethering because of a more caudal dural sac termination should be investigated.

Association between filum terminale internum length and pain in Cavalier King Charles spaniels with and without syringomyelia

“…In previous work, we found that TL but not cervical SM was significantly associated with the location of dural sac termination in CKCS. 6 In the current study, we were unable to draw statistical comparisons for dogs with cervical SM because only 2/48 dogs (4%) had cervical SM only. Dural sac termination appeared to be located more caudally in dogs with lumbar SM, but this relationship was not significant ( Figure 3).…”

“…Cavalier King Charles spaniels (CKCS) are affected by Chiari‐like malformation (CM) and syringomyelia (SM) causing neuropathic pain and parasthesias of the head and neck region. Syringomyelia was first noted in the cervical spinal cord using magnetic resonance imaging (MRI) but more extensive imaging protocols identified its presence in the thoracic and lumbar spinal cord 1‐6 . The etiology of clinical signs in CKCS with Chiari‐like malformation with syringomelia (CMSM) is unclear.…”

“…Syringomyelia was first noted in the cervical spinal cord using magnetic resonance imaging (MRI) but more extensive imaging protocols identified its presence in the thoracic and lumbar spinal cord. [1][2][3][4][5][6] The etiology of clinical signs in CKCS with Chiari-like malformation with syringomelia (CMSM) is unclear. Many studies have found an association between the presence and the severity of SM with clinical signs.…”

The Need for Head Space: Brachycephaly and Cerebrospinal Fluid Disorders

“…In comparison to dogs with Chiari-like malformation only, dogs with syringomyelia have more extreme brachycephaly with craniocervical junction deformation, including cervical flexure, change in angulation of the odontoid peg, increased proximity of the atlas to the skull (often referred to as atlanto-occipital overlapping), kinking or elevation of the craniospinal junction, and loss of the cisterna magna [ 13 , 75 , 82 , 83 , 84 ]. Changes in conformation of the spinal canal and cord may also contribute [ 85 , 86 ]. The authors propose that syringomyelia develops due to a combination of reduced CSF absorption though nasal lymphatics, reduced venous drainage, altered neuroparenchymal compliance, and reduced CSF movement through the lateral apertures or craniocervical junction.…”

Comparison of inherited neural tube defects in companion animals and livestock

“…De Decker et al (2015) suggests that it can be hard to diagnose this due to natural variations of the conus medullaris in dogs. In cavalier King Charles spaniels, Sparks, Robertson, and Olby (2019) examined the possibility of the association of tethered cord syndrome with Chiari malformation and syringomelia both of which are common in the breed. In the cavalier King Charles spaniel, they noted that the dural sac is more caudally located than other breeds of comparable weight, and the spinal cord is also caudally displaced.…”