Association between filum terminale internum length and pain in Cavalier King Charles spaniels with and without syringomyelia.
BACKGROUND
Lumbar syringomyelia (SM), lumbosacral pain, and more caudal spinal cord termination are reported in Cavalier King Charles spaniels (CKCS). Data are lacking on the clinical relevance of alterations in their spinal cord terminal structures.


OBJECTIVES
To compare spinal cord termination level and filum terminale internum length (FTIL) with presence of lumbar SM and clinical signs in CKCS.


ANIMALS
Forty-eight CKCS.


METHODS
In this prospective study, pain was quantified using owner and clinician assessments. Vertebral level of spinal cord and dural sac termination, presence of SM, and FTIL were determined from sagittal magnetic resonance imaging (MRI) sequences. Kappa and intraclass correlation (ICC) analyses determined interobserver reliability. The MRI findings were compared to owner and clinician-reported pain quantification.


RESULTS
Interobserver reliability was good for spinal cord and dural sac termination (kappa = 0.61 and 0.64, respectively) and excellent for FTIL (ICC: 92% agreement). The spinal cord terminated at 6th lumbar vertebra in 1, 7th lumbar vertebra in 31, and the sacrum in 15 dogs, and termination level was associated with lumbar SM (P = .002) but not clinical signs. Mean FTIL was 2.9 ± 1.08 mm; it was associated with owner-reported pain (P = .033) and spinal palpation scores (P = .023). Painful CKCS without SM had shorter FTIL compared to normal CKCS and painful CKCS with SM (P = .02).


CONCLUSIONS
Painful CKCS without SM have decreased distance between the termination of the spinal cord and dural sac, suggesting a shorter FTIL. More caudal spinal cord termination is associated with development of lumbar SM.
['Sparks|Courtney R|CR|', 'Woelfel|Christian|C|', 'Robertson|Ian|I|', 'Olby|Natasha J|NJ|https://orcid.org/0000-0003-1349-3484']
D000818:Animals D002420:Cauda Equina D004283:Dog Diseases D004285:Dogs D008279:Magnetic Resonance Imaging D010146:Pain D011446:Prospective Studies D015203:Reproducibility of Results D013595:Syringomyelia
dural sac Chiari-like malformation conus medullaris morphometry tethered cord