Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Comparative and Experimental Medicine

Major Professor

Darryl L. Millis

Committee Members

Silke Hecht, Marti S. Drum


Introduction: Lumbosacral pain and stenosis are common causes of retirement from duty for Military Working Dogs (MWDs). Working dogs that receive surgical management for this condition often have a poor prognosis for return to duty after recovery. Humans with chronic low back pain demonstrate paraspinal muscle asymmetry, pain and dysfunction that often improve in response to an exercise program. This study investigated whether dogs with mild lumbosacral pain have decreased lumbar paraspinal muscle area, symmetry, and density, as well as increased pain and dysfunction compared to control dogs. Additionally, response of pain and dysfunction to an exercise program was assessed.

Materials and Methods: Visual Analog Scale (VAS) scores for lumbosacral pain, functional questionnaire scores for search and detection tasks, and computed tomography images were evaluated for eight MWDs with lumbosacral pain along with eight control dogs. Mean cross-sectional muscle area (CSA)-to-vertebral ratio, asymmetry and density were determined for five lumbar paraspinal muscles bilaterally at the L5, L6 and L7 caudal endplates. Four dogs with lumbosacral pain rested and four dogs completed an eight-week core stabilizing exercise program. Repeated assessments of lumbosacral pain, dysfunction and muscle parameters for dogs with lumbosacral pain were made at the conclusion of the exercise program.

Results: The multifidus lumborum and longissimus lumborum muscles demonstrated significantly reduced CSA (p= 0.020, p = 0.021, respectively) in dogs with lumbosacral pain. Muscle density was decreased in dogs with lumbosacral pain for multifidus lumborum (p = 0.030) and quadratus lumborum (p = 0.011). Multifidus lumborum muscle CSA (p = 0.019), symmetry (p = 0.002) and density (p = 0.024) were significantly higher than at baseline for dogs with LS pain after completion of the exercise program. Functional questionnaire scores improved significantly for exercised dogs (p = 0.031) but did not improve for rested dogs (p = 0.828).

Discussion: Military Working Dogs with mild lumbosacral pain and dysfunction had significantly smaller CSA, symmetry and density for both multifidus lumborum and longissimus lumborum muscle groups. An 8-week core strengthening program was associated with significantly improved performance in evaluated tasks for dogs with lumbosacral pain.

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