Page 220 - Adams and Stashak's Lameness in Horses, 7th Edition

186 Chapter 2

aspect of the greater trochanter of the femur (Figure 1.48
in Chapter 1). The site for injection is between the ten­
VetBooks.ir the most cranial aspect of the palpable greater trochanter.
don and the lateral surface of the greater trochanter at
A 1.5‐inch (3.8‐cm), 18‐gauge needle is usually all that is
needed, although larger Warmblood horses may require
a longer needle in some cases. The needle is inserted
28
and directed horizontally at right angles to the sagittal
plane until bone is encountered. Seven to 10 mL of anes­
thetic is injected. An alternate method is to direct the
needle medially through the middle gluteal muscle
75
directly over the bursa toward the trochanter. A recent
study concluded that positioning the limb caudally with
the foot non‐weight‐bearing and on a Hickman block
facilitated centesis of the trochanteric bursa. The
78
author has also recommended using ultrasound guid­ Figure 2.197. Craniolateral view of the injection site for the
ance to improve the success of the injection. 78 coxofemoral joint. The needle is inserted in the trochanteric notch
and directed at a 45° angle with the long axis until the joint is
entered. Ultrasound guidance is recommended to enter the
Coxofemoral (Hip) Joint coxofemoral joint regardless of the approach used.
The coxofemoral joint is one of the most difficult
joints to enter. 34,48 This is particularly true in mature, in periarticular deposition of medication (not intra‐
heavily muscled horses. The joint is well away from the articular). A cadaver study of two different ultrasound‐
proximal end of the femur, and the landmarks for injec­ guided injection techniques (cranial parasagittal and
tion are often difficult to palpate. For these reasons, caudomedial) concluded that accuracy was poor for
74
ultrasound guidance of the needle is recommended. 15,82 intra‐articular injection. The described technique by
The procedure is best performed with the horse standing Engeli and Haussler is used by the author and is
squarely and restrained within stocks. Mild sedation is described here. The horse is usually sedated, restrained
22
often advised because movement during the injection in stocks, and the injection site is anesthetized with local
procedure may cause the needle to bend or break. anesthesia. The landmark for injection is the cranial
Both craniodorsal and cranioventral approaches have aspect of the tuber sacrale. A 10‐inch (25‐cm), 15‐ to
been described. The cranioventral approach requires 16‐gauge spinal needle is bent to an angle of about 40°
ultrasound guidance, while the craniodorsal approach in the direction of the needle’s bevel. The needle is
82
may be performed blindly or more optimally with ultra­ inserted through a stab incision in the skin 1 inch (2 cm)
sound guidance. The most important landmarks for cranial to the contralateral tuber sacrale and directed at
15
the craniodorsal approach are the paired summits of the a 60° angle to the vertical plane. The needle is advanced
greater trochanter of the femur. The trochanter is located across midline aiming for a point midway between the
about two‐thirds of the distance between the tuber ipsilateral tuber coxae and the greater trochanter of the
coxae and the tuber ischii. The greater trochanter is femur until it contacts the medial aspect of the tuber
48
approximately 4 inches (10 cm) wide with a notch sacrale (Figure 2.198). The needle hub is lifted, and the
between the cranial and caudal protuberances that can needle is advanced at a steeper angle along the medial
be difficult to palpate. The site for injection is about 0.5 aspect of the ilial wing until it contacts the dorsal sur­
inches (1–2 cm) above the middle of the proximal sum­ face of the sacrum at a depth of approximately 6–8
mit of the trochanter (Figure 2.197). A small bleb of inches (15–20 cm). An alternative technique is to insert
48
48
local anesthetic is injected subcutaneously over the a 6‐inch (15‐cm), 18‐gauge needle near the cranial aspect
injection site, and a small stab incision may aid needle of the tuber sacrale. The needle is directed ventrocau­
insertion. A 6‐ to 8‐inch (15‐ to 20‐cm), 16‐ to 18‐ dolateral toward the SI joint of the opposite side at a
2,3
gauge spinal needle is directed in a horizontal plane per­ 20°–40° angle to the vertical plane. Ultrasound guid­
19
pendicular to the vertebral column (Figure 2.197). The ance of SI injections is commonly performed, and both
needle should be directed slightly downward to stay cranial and caudal approaches have been described. 16,74
close to the femoral neck so that it is approximately 0.5 The reader is referred to Chapter 6 for additional infor­
inches (1–2 cm) lower than the insertion site after it has mation on SI injection techniques.
been advanced 3–4 inches (8–10 cm). Firm fibrous tissue
is often felt just before the needle penetrates the joint Cervical Facets
capsule at approximately 4–6 inches (10–15 cm).
Synovial fluid is often aspirated and 30–60 mL of anes­ Centesis of a cervical facet joint is usually performed
thetic is recommended. 34,48 to administer medication into the joint of a horse that
has clinical signs suggestive of disease within the cervi­
cal articulation. Lesions of the cervical facets tend to
Sacroiliac (SI) Joint occur most commonly in vertebrae C5 to C6 and C6 to
The SI joint is not a true synovial joint, but treatment C7. The procedure is performed in the standing sedated
44
of this region is common in horses with sacroiliac prob­ horse with the help of ultrasound and is usually per­
lems. There are several different approaches that can be formed bilaterally unless a specific side of the lesion has
used to access the sacroiliac region with most resulting been documented. The approximate location of the