Page 293 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

268 CHAPTER 1

VetBooks.ir Diagnosis Management
Pain in all its different types is the usual limit-
Narrowing of the interspinous spaces is palpable
in the thoracic region with a surprisingly high
normal function is needed. Systemic or local anti-
degree of accuracy. Each interspinous space is felt ing step, so management to reduce pain and restore
as a regularly spaced depression on the midline; inflammatory and/or counterirritant medication,
the depressions between DSPs cannot be felt with bisphosphonate drugs, acupuncture and mesotherapy
impingement. This test is less reliable in the lumbar have all been used with success, usually in combination
area, where depressions can be felt despite impinge- with some form of manipulative therapy; for example,
ment. Radiography is required to demonstrate the physiotherapy, osteopathy or chiropractic. Published
full extent of impingement (Figs. 1.506, 1.507) success rates following non-surgical management are
and other pathology elsewhere in the back. Focal very limited, but short-term success rates similar to
consistent back pain in the region of radiographic surgical options should be anticipated, with 70–80%
DSP impingement may be enough for a diagnosis. of affected horses experiencing resolution of symp-
The majority of horses do not have such clear signs toms for 4–6 weeks. Between 30 and 40% of these
of focal pain, necessitating further tests to prove horses experience recurrence of symptoms when
cause and effect. Local anaesthetic can be infiltrated the medication wears off. Surgical management has
into the affected interspinous spaces (Fig. 1.508) or similar success rates, which often persist significantly
immediately adjacent, and the horse is re-evaluated longer. Consequently, surgery is increasingly consid-
straight away, preferably when ridden. Care should ered sooner, sometimes in preference to medical treat-
be taken when blocking the back because of the ment. Several surgical options exist, under general
potential for false positives in normal horses due to anaesthesia or standing sedation and local analgesia.
disruption of proprioceptive pathways. Alternatively, Most studies describing surgery agree that the num-
corticosteroids can be injected into the same affected ber of spaces involved, and the radiographic severity
spaces and the horse re-evaluated after 2 to 3 weeks. of signs, are unrelated to outcome. Traditionally
Scintigraphic examination may demonstrate local the involved DSPs are removed in toto (Fig. 1.510).
increased metabolic activity; unfortunately, false Wedge resection has become an increasingly popu-
negatives and positives are frequently encountered, lar alternative, whereby a section of DSP is sharply
undermining the value of this imaging modality removed from the cranial aspect, or cranial and
when used in isolation (Fig. 1.509). caudal aspects, thereby giving the DSP a shortened

1.509

Fig. 1.509 Bone scan of the thoracolumbar spine and pelvis of a horse with back pain. Note the
radiopharmaceutical uptake in several dorsal spinous processes in the thoracic region and also associated
with the dorsal facet joints of the thoracolumbar junction. Additional diagnostic methods will be required to
ascertain the significance of these findings. (Photo courtesy Graham Munroe)