Morphometric analysis of spinal cord termination in Cavalier King Charles Spaniels.

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.