Abstract
Study design
Retrospective, comparative study.
Animals
A total of 24 dogs with clinically suspected, MRI-confirmed DLSS that underwent dynamic LSJ imaging.
Methods
Medical records and MRI findings of included cases from three referral hospitals were reviewed. Quantitative and qualitative assessments of the LSJ (LSJ angle, protrusion ratios, degree of intervertebral disc [IVD] protrusion, ventral bulging of the ligamentum flavum [VBLF], foraminal compression) were compared in neutral and flexed positions. Their correlations with the degree of IVD degeneration or spondylosis was evaluated. Interindividual agreement was assessed among three observers.
Results
Degree of IVD protrusion, foraminal stenosis, VBLF, and protrusion ratios, were significantly reduced in flexion compared with neutral position (p < .001 for all comparisons). No dogs had persistent compression of the cauda equina or completely occluded foramina in flexion. The response of IVD protrusion to flexion was significantly directly correlated to the degree of IVD degeneration (p = .004), but not of spondylosis.
Conclusion
In flexed position, IVD protrusions, VBLF and foraminal stenoses improved in all cases, with resolution of all compression sites.
Clinical significance
With LSJ distraction-stabilization techniques, the need for concurrent decompressive dorsal laminectomy/partial discectomy or foraminotomy should be questioned, unless performed for IVD-spacer placement. Surgical case–control studies are required to investigate this further.