Calcification of extruded intervertebral discs in dachshunds: a radiographic, computed tomographic and histopathological study of 25 cases

Abstract

Background Three Nordic countries have national breeding programs to reduce the frequency of intervertebral disc disease in dachshunds. The programs include a radiographic examination of the vertebral column and dachshunds with more than four calcified discs visible on radiographs (CDVR) are discouraged from use in breeding. However, disc extrusion is also diagnosed in dachshunds without CDVR. The utility of the breeding programs is therefore questioned. Results A prospective study of 25 dachshunds surgically treated for disc extrusion was conducted. For all the dogs, preoperative radiographs were evaluated for detectable disc calcifications and preoperative computed tomography (CT) scans were evaluated for presence of calcified material in the vertebral canal. Postoperatively, extruded disc material was examined for degeneration and calcification by histology. Diagnostic imaging and histology were done independently. Radiographically visible calcification was identified in 17 (68.0%) of 25 extruded discs. Calcification was seen in the disc space for all these 17 discs, and for eight of the 17, there was also calcified material visible in the vertebral canal. Extruded material from all the 25 discs was found to be calcified, both by CT and histopathology. Conclusions In dachshunds with acute disc extrusion, radiographically visible calcification will frequently be found in the affected disc space, but not all affected disc spaces contain radiographically visible calcification. Using histopathology as the gold standard, a sensitivity of 0.3 (8/25) for radiography and 1.0 (25/25) for CT was found for detecting calcified disc material in the vertebral canal. Further, a sensitivity of 0.7 (17/25) was found for radiography for detecting remaining calcified material in the disc space. Thus, extruded disc material should be considered to be calcified, even in the absence of radiographically visible calcification.

Phenotypic Effects of FGF4 Retrogenes on Intervertebral Disc Disease in Dogs

“…Among the Dachshund surgical cases in this study, 9.4% had no radiographic evidence of disc calcification. These results are similar to previous retrospective studies in Dachshunds and Pekingese that found that 13% and 17% of cases with disc extrusions had no radiographic calcification [39,40], likely reflecting low sensitivity (0.3–0.6) compared to histopathological assessment, as well as limitations of calcification as the sole marker for “clinically” relevant pathology [41,42].…”

Current Insights Into the Pathology of Canine Intervertebral Disc Extrusion-Induced Spinal Cord Injury

“…The latter progressively degenerates and calcifies in the late stage of IVD degeneration (2,17). In dachshunds with acute disc herniation, histopathology reveals that the majority of extruded disc material is calcified, even in the absence of radiographically visible calcification (18). More recent histopathological studies propose a grading scheme for intervertebral disc degeneration based on an assortment of parameters.…”

Epidemiological study of congenital malformations of the vertebral column in French bulldogs, English bulldogs and pugs

“…Intervertebral disc degeneration itself is known to increase the risk for compressive intervertebral disc disease and therefore neurological deficits. 8,35,36 Further, a significant association between intervertebral disc extrusion and kyphosis has been described for French Bulldogs and Pugs. 9,23 So, despite the low number of the two discussed vertebral malformations (14/707) associated with neurological deficits in this study, our findings can be interpreted in agreement with recent literature.…”

“…Faller et al 21 described a higher prevalence of intervertebral disc degeneration in dogs with kyphoscoliosis. Intervertebral disc degeneration itself is known to increase the risk for compressive intervertebral disc disease and therefore neurological deficits 8,35,36 . Further, a significant association between intervertebral disc extrusion and kyphosis has been described for French Bulldogs and Pugs 9,23 .…”