Quantitative Bone Scintigraphic Follow-Up After a 2-Month Cross-Training Program Including Swimming in Showjumping Horses with Back and Neck Pain.

To quantitatively describe changes in skeletal radiopharmaceutical uptake during a training program including swimming in horses with neck and back pain, eighteen showjumping horses with documented vertebral lesions were prospectively included in a training program composed of 4 weeks of ridden work and then 8 weeks combining swimming and ridden exercise. Previously published data on this cohort did not demonstrate any clear change in thoracolumbar mobility. Bone scintigraphy was performed at the 4th and 12th weeks. Radiopharmaceutical uptake was quantified in 205 regions of interest (ROIs) and normalized using a Z-score approach. For each ROI, a linear mixed-effects model was fitted to evaluate the effect of the time point (W4, W12) on the normalized radiopharmaceutical uptake with the horse as a random effect. Overall variation in normalized signal intensity (Z-score difference W12-W04) was small (mean < 0.001; range -0.28 to 0.24). Significant changes between time points were identified in 21 ROIs. Thirteen ROIs located in the axial skeleton showed a decreased radiopharmaceutical uptake, whereas eight ROIs located in the limbs, including the humeral tubercles on both lateral views, showed an increased uptake. During a 2-month training program including swimming, axial skeletal radiopharmaceutical uptake did not increase in this cohort of horses with neck and back pain. However, substantial interindividual variability in scintigraphic changes was observed. Further controlled studies are needed to confirm these preliminary results and to better explore the effects of swimming on horses with axial musculoskeletal disorders.