The diagnostic performance of vertebral displacement measurements derived from ultrasonic indentation in an in vivo model of degenerative disc disease.
METHODS
The diagnostic performance of a newly described variable was assessed in an in vivo model of disc degeneration using a split-pair experimental design.


OBJECTIVE
To determine if vertebral displacement measures generated from ultrasonic indentation could distinguish between experimental and control groups of animals.


BACKGROUND
Few procedures are available that noninvasively assess subcutaneous vertebral mechanics. Information from such a procedure would be of value in determining potential clinical relevance of spinal mechanics with respect to low back pain.


METHODS
Eight adolescent pigs underwent endplate perforation surgery to initiate lumbar disc degeneration. After 4 months of recovery, these and eight age-matched controls were assessed by ultrasonic indentation, a noninvasive procedure that quantifies vertebral displacements in the plane of loading-indentation. Each animal then received a facetectomy and was reindented at the same location as confirmed by ultrasonic imaging. Discal materials were removed postmortem for analysis.


RESULTS
Degenerative discs exhibited morphologic changes consistent with early degenerative disc disease. Prefacetectomy comparison of vertebral displacement measures between control and experimental animals resulted in sensitivity, specificity, and diagnostic accuracy values of 75.0%, 83.3%, and 77%, respectively. After facetectomy these values increased to 87.5%, 83.3%, and 85%, respectively. These measures of diagnostic performance were comparable or superior to those of existing clinical techniques (invasive or otherwise) used to assess degenerative conditions of the spine.


CONCLUSIONS
The results of this study suggest that noninvasive measures of vertebral displacement are clinically significant and possess the additional advantages of being objective and noninvasive.
Kawchuk
G N
GN
Department of Orthopaedics, Sahlgrenska University Hospital, Göteborg, Sweden. kawchuk@ucalgary.ca
Kaigle
A M
AM
Holm
S H
SH
Rod Fauvel
O
O
Ekström
L
L
Hansson
T
T
D000818:Animals; D004195:Disease Models, Animal; D007403:Intervertebral Disc / Q000000981:diagnostic imaging* / Q000293:injuries / Q000503:physiopathology; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000293:injuries / Q000503:physiopathology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016103:Spinal Fractures / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D013314:Stress, Mechanical; D013552:Swine; D014463:Ultrasonography; D016474:Weight-Bearing