Page 287 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

262 CHAPTER 1

VetBooks.ir Mesotherapy involves injections of small quantities vertebral facet joints and vertebral bodies. Of these,
fractures of the DSPs, which are most common at
of a combination of corticosteroid, local anaesthetic
and a myorelaxant subcutaneously into the derma-
when rearing in young animals, are usually displaced
tomes corresponding to the proposed sites of pathol- the withers (T2–T9) and caused by backward falls
ogy over the thoracolumbar region, and is popular in due to the ventral pull of the supraspinous ligament.
continental Europe. They can become infected if associated with an open
Restoration of normal function and symptomatic wound (Figs. 1.496, 1.497) and can also involve
resolution of pain, or the behavioural symptoms of the supraspinous bursa, allowing a fistula to form
it, are the most important means of judging treat- if infection persists (see Fig. 1.491). Fractures of
ment success. Ultrasound can be used to monitor the vertebral bodies may result in acute and severe
healing (reduction in diameter, return of fibres to neurological signs due to spinal cord compression.
normal alignment). Reversing the muscle atrophy Hindlimb paresis or paralysis with normal forelimb
seen with more chronic injuries is an alternative function is suggestive of a lesion caudal to T2.
means of monitoring progress. The vertebral lamina at the base of the DSP
appears to be a predilection site for incomplete
FRACTURES stress fractures and subsequent remodelling in flat
racing Thoroughbreds. Similar to other stress frac-
Definition/overview tures elsewhere, they result from repeated mechani-
The incidence of complete fractures of the thoracic, cal overloading. They may be responsible for poor
lumbar or sacral vertebrae is low. A survey of 443 performance or other signs of back pain. In foals,
horses with a history of thoracolumbar pain included vertebral end-plate fractures or separations may
five (1.13%) with vertebral body fractures and eight occasionally be seen following trauma during or
(1.81%) with fractured DSPs. soon after parturition (Fig. 1.498).

Aetiology/pathophysiology Clinical presentation
Acute vertebral fractures are traumatic, usu- The clinical appearance of a horse with a fracture
ally caused by heavy falls or road traffic collision. will vary depending on the location (within the back
Broadly, fractures occur in three locations: DSPs, and the individual vertebra) and type of fracture.

1.496 1.497

Figs. 1.496, 1.497 (1.496) Chronic purulent discharge from the withers of a horse several months after it
sustained a wound to the withers during a fall. (1.497) Laterolateral radiograph of the withers of the same horse.
Note that the dorsal part of the DSP of T3 is missing, with evidence of osteomyelitis in the surrounding part
of the process. Also note the overriding fractures of the DSPs of T4 and T6, which occurred at the original
traumatic episode. (Photos courtesy Graham Munroe)