Page 284 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.7b The axial skeleton – thoracolumbar region 259

VetBooks.ir work with a low head carriage, pushing from behind SOFT-TISSUE TRAUMA
and building support musculature around the back.
Water treadmills can also be helpful, but water depth Definition/overview
should be no higher than the shoulder to prevent an The soft tissues of the thoracolumbar region are
excessively high head carriage and compensatory subject to potential injury, with affected structures
dipped back posture. Swimming is contraindicated including the skin, muscles (epaxial and hypaxial),
for the same reason. ligaments, nerves and blood vessels.
Foot pain is very common in horses and can rap-
idly induce back dysfunction, therefore optimising Aetiology/pathophysiology
foot balance and support is a helpful and often over- These injuries are caused either by one-off trauma,
looked therapeutic step for horses with back pain. such as a fall, or chronic repetitive wear and tear
Acupuncture may provide analgesia for some tho- through dysfunction, compensation or iatrogenic
racolumbar conditions through the stimulation of factors such as riding the horse continually with a
endogenous endorphin-like dynorphin in the dor- maximally flexed neck with an excessively low head
sal horn. Electroacupuncture at higher frequencies carriage. Poor fitting tack is one of the most com-
(15–100 Hz) provides greater stimulation that plain mon causes of muscle pinching and pain. Acute
needle acupuncture and more effectively increases damage to the deeper soft-tissue structures of the
endorphin release (Fig. 1.489). Manipulative man- thoracolumbar spine requires considerable force,
ual techniques of massage and physiotherapy are of such as that encountered after a fall, becoming cast
very great benefit in the reduction of pain and these or a road traffic accident. With sufficient force, liga-
are discussed in the section covering back pain with- ment, nerve or even bone injury can occur. Excessive
out apparent trauma. force exerted on a muscle or ligament may cause
Successful treatment and rehabilitation inevitably rupture or detachment from an origin or insertion;
require a collaborative approach involving physical however, most injuries are less severe. Ligaments
therapists, farriers and veterinarians. Heavy riders, respond to injury by an increase in diameter and
as well as equine obesity, are both increasing issues in the slow repair phase is characterised by irregular
the 21st century, with a number of studies concluding alignment of collagen fibres. New bone may form
that horses should carry an absolute maximum of at a ligament origin or insertion site (Fig. 1.490).
20% of their lean body weight, including tack. Chronic pain may arise from damage to, and contin-
ued tearing of, poorly healed insertion sites (enthe-
seopathy). Bony pathology of the vertebrae, such as
overlapping DSPs, may result in secondary damage
1.489
to muscles and ligaments. The supraspinous bursa,
lying between the supraspinous ligament and the
tips of the cranial thoracic DSPs at the withers, can
become infected following a wound at this site (‘fis-
tulous withers’) or, less commonly, as a consequence
of chronic infection by Brucella abortus or Actinomyces
bovis (Fig. 1.491). Haematomas may occur in the
vicinity of the withers and can be exceptionally pain-
ful. Penetrating injuries can introduce foreign mate-
rial and bacteria into the epaxial muscles, causing
infectious myositis (Fig. 1.492).

Clinical presentation
Fig. 1.489 Electroacupuncture being carried out on Acute back trauma typically induces focal swelling,
a horse with lumbar pain. heat, crepitus and avoidance behaviour. Asymmetry