News Notes

Lumbosacral Pain Points to a Number of Pathological Changes

Lumbosacral region pain may reflect the presence of a number of pathological changes.

In addition, neural pain may play an important role in lumbosacral region pain in some horses, according to a recent study.

Veterinary medicine does not have a clear understanding of the pathological and/or physiological nature of lumbosacral region pain, the U.K. researchers said. To gain a better understanding of the painful process, they did a post-mortem study to examine the gross variations of osseous and soft tissues, and histopathological features of nerve tissue in the lumbosacral region of affected and control horses.

The researchers looked at horses that were euthanized because of lameness or a definitive diagnosis of poor performance. Twenty-seven horses that had a substantial response to a localized anesthetic block around the sacroiliac joint regions were included in the affected group, and 5 horses that were painful in another region (also confirmed by diagnostic anesthesia) were used as controls. Of the affected horses,

• 24 (89%) had concurrent hindlimb lameness,

• 13 (48%) had concurrent forelimb lameness,

• 6 (22%) had neurological gait deficits and,

• 2 (7%) had axial skeleton pathology.

Of the unaffected horses,

• 3 (60%) had concurrent hindlimb lameness,

• 3 (60%) had concurrent forelimb lameness and,

• 2 (40%) had axial skeleton pathology.

They also assessed the soft tissues of the pelvic regions. They use histology to examine sections of the lumbosacral plexus and cranial gluteal, sciatic and obturator nerves, and the osseous specimens were evaluated for anatomical variants and abnormalities.

Several osseous variants and abnormalities appeared more frequently in affected horses. They observed gross discoloration of the sciatic or obturator nerves in 26% of the affected horses, but none of the controls. Grade 3/3 histological abnormality scores were assigned in 22% of nerve sections from affected horses compared with 3% from control horses.