Download AVOIDING CASTI (CAST AND SPLINT VETERINARY ORTHOTICS

AVOIDING CASTI (CAST AND SPLINT
ASSOCIATED SOFT TISSUE INJURY)
Patrice M. Mich, DVM, MS, DABVP, DACVAA, CCRT
VETERINARY ORTHOTICS
& PROSTHETICS
Types of External Coaptation
External coaptations generally can be categorized as bandages, splints, braces, or orthoses. Each of these can be
further subdivided into specific types or applications as well as by the use of different materials. It is important to
understand the intended purpose in order to select the proper coaptation.
•
•
•
•
•
Bandage: A strip of material, such as gauze, used to protect, immobilize, compress, or support a wound or
injured body part
Wrap (support): An elastic material used primarily for support and muscle compression; to shorten a
muscle’s angle of pull; to reduce a joint’s range of motion; or to apply compression to reduce swelling
Splint: A rigid or flexible appliance for fixation of displaced or movable parts
Brace: An orthopedic appliance that supports or holds a movable part of the body in correct position while
allowing motion of the part
Orthosis: Any medical device attached to the body to support, align, position, prevent, or correct deformity,
assist weak muscles, or improve function. The term “orthosis” is a more correct term in that it expands the
concept of bracing and more specifically defines the various clinical applications possible.
Proper application can be challenging in veterinary species. Differences in patient size, coat type, injury location and
severity, temperament and activity level must be considered. Attention must be paid to the intended purpose and
duration of use. Finally, secure attachment and alignment to the limb can be challenging; these are critical in terms
of function, comfort, and safety.
Bandages and Wraps
Advantages: they come in variable thicknesses; some are reusable and some are disposable; they are inexpensive,
are used for wound protection, and can incorporate wound dressing materials and medications.
Disadvantages: they must be replaced if wet; they cannot provide support against a significant increase in range of
motion (e.g., carpal hyperextension); they can be difficult to keep in place and properly aligned; they may cause
wounds or binding (pressure and friction); and they carry the risk of the tourniquet effect or of skin irritation from
repeated tape application and removal.
Splints
Advantages: they are inexpensive; some are moldable; some are reusable; they provide rigid support, if needed.
Disadvantages: they must be applied with bandage material, which can become wet; they are not dynamizable (no
articulation); distal joints unaffected by injury are immobilized (iatrogenic consequences, such as flexor contraction
and joint capsule fibrosis, must be managed); they can cause atrophy by virtue of fixed joint angles; they can be
difficult to keep in place and properly aligned; they may cause pressure wounds; and they carry the risk of the
tourniquet effect or of skin irritation from repeated tape application and removal.
Braces and Orthoses
Advantages: they are body-part-specific and injury specific; they are reusable; they provide rigid support, if needed;
some are dynamizable (articulated, variably articulated, or not articulated); some are moldable or customizable; they
have improved retention on the limb; tape is not needed (due to designed suspension and Velcro attachment); their
ease of removal and reapplication allows for frequent examination of the injured area; they can get wet; and
replacement parts are available, for some.
Disadvantages: They are more expensive, and best used for longer term use ( > 8 weeks); they can cause wounds
and distal-extremity swelling, if not properly designed, adjusted, and monitored; no controlled clinical studies are
yet available; and there is a lack of professional fabricators who are knowledgeable in the design, manufacture, and
use of these devices for veterinary species.
A common misconception is that splints are the same as braces (orthoses), and further, that all such devices lead to
disuse atrophy as a consequence of reliance on the device. This idea has led to an incorrect and unfortunate tendency
to avoid the use of mechanical appliances in both short- and long-term patient care. In this lecture we will explore
the significant therapeutic differences and applications of splints and orthoses and debunk the myths surrounding
their use in rehabilitation.
Mechanical Principles of Proper Bandaging, Splinting, and Bracing
The mechanical basis of splinting and bracing is the Three-Point Pressure Principle (3PPP). Properly applied, the
3PPP employs a single force at the area of correction or at the area of deformity or angulation while two
counterforces act in opposing directions, usually above and below the primary area of correction (Figures 1 and 2).
Figure 1
Figure 2
The further the counterforces from the joint center the more torque and less force required to achieve alignment.
Therefore, the 3PPP is also the root cause of most wounds associated with bandaging as well as splinting and
bracing. The magnitude of force placed on the skeleton through soft tissue is greater the closer the contact point is to
the fulcrum or corrective force (Figure 3). It is not surprising, therefore, that pressure wounds occur at CF1 and CF2,
especially when bandages, splints, or orthoses are too short. Additionally, the more acute the joint angle, the more
force required (CRF3) to realign the segment and therefore, since CF1 + CF2 = CRF, the greater the force applied to
the skin at CF1 and CF2 (Figure 4). It is not surprising to find wounds, for example, at the olecranon, the accessory
carpal bone/pad, or the calcaneal tuberosity.
Figure 3
Figure 4
Pressure must be evenly applied over the entire structure. If it is not, wounds occur at points of increased contact.
Good examples include the medial and lateral malleoli and the radial and ulnar styloids. In bandaging, splinting, or
bracing, accommodation must be made on these structures such that pressure above and below these points is the
same as directly over these points.
Several resources are available with regard to bandaging, splinting, and bracing. See References below for more
information.
References
Adamson C, Kaufmann M, Levine D, Millis DL, Marcellin-Little DJ. Assistive devices, orthotics, and prosthetics.
Vet Cl N Am, 2005;35(6):1247–1518.
Deshales LD. Upper extremity orthoses. In CA Trombly, MV Radomski, eds., Occupational therapy for physical
dysfunction, 5th ed. Baltimore: Lippincott, Williams and Wilkins, 2002, 313–349.
Mich PM, Fair L, Borghese I. Assistive devices, orthotic, prosthetics, bandaging. In VanDyke J, Zink MC, eds.,
Canine sports medicine and rehabilitation. Hoboken, NJ: Wiley-Blackwell, in press.
Mich PM, Kaufmann, MW. Custom external coaptation as a pain management tool: veterinary orthotics and
prosthetics (V-OP). In Egger C, Doherty T, eds., Pain management in veterinary practice. Hoboken, NJ:
Wiley-Blackwell, in press.
Prokop LL. Upper extremity orthotics in performing artists. Phys Med Rehabil Clin N Am 2006;17:843–852.
Swaim SF, Renberg WC, Shike KM. Small animal bandaging, casting, and splinting techniques. Hoboken, NJ:
Wiley-Blackwell, 2011.