Splinting Techniques

Support Materials

Woodcast Composite Splinting Material

A new synthetic material that has had a limited presence in the United States, but looks promising in European studies is Woodcast (Onbone Oy, Helsinki, Finland). Woodcast is made from spruce tree chips and biodegradable plastic, making it nontoxic and environmentally friendly. The material comes in slabs ranging from 1-to-4 mm thick from which the provider can cut out the desired shape for a specific splint. Woodcast splits are applied in the same manner as conventional splints ( Fig. 50.2 ) and have comparable stiffness. Like splints made from plaster of Paris and fiberglass, increasing the thickness of the split increases its ultimate strength. The composite material is easily molded to the contour of an extremity or digit by heating for 15 minutes to a temperature of 65°C using one of the Woodcast heating devices ( Fig. 50.3 ). The material takes approximately 15 minutes to set, providing sufficient time for applying and molding the splint. If needed, setting time can be reduced to 5 to 10 minutes with application of ice packs. Woodcast splints can be rewarmed and remolded after application and gloves are not required when handling the material. Compared to conventional splinting materials, Woodcast splints cause fewer skin reactions, and are associated with similar rates of healing and patient satisfaction.

Protective and Miscellaneous Equipment

Elastic Bandages

Elastic bandages are used to secure the splint in place. Elastic bandages are available in 2-, 3-, 4-, and 6-inch widths. Some bandages use metal clips, whereas others use a Velcro-type mechanism to secure the bandage in place. Metal clips should be taped in place to avoid inadvertent removal.

Patients often use or request an elastic bandage for many soft tissue injuries. Although applying an elastic bandage to an injured part is popular, it is of minimal benefit alone. The downside is that the bandage may be wrapped too tightly and cause additional injury or distal swelling ( Fig. 50.4 ).

Patient Preparation

If the clinical situation permits, cover the patient with a sheet or gown to protect clothing and the surrounding area from water and plaster. Nursing staff and housekeeping also appreciate this courtesy. Properly drape hallway patients if areas of the body are exposed. Carefully inspect and examine the involved extremity before splinting, and clearly document the presence of all skin lesions and soft tissue injuries. Clean, repair, and dress all wounds in the usual manner. When open fractures or joints are to be immobilized, cover the soft tissue defect with saline-moistened sterile gauze.

Padding

When the splint involves the digits, place padding between the fingers and toes to prevent maceration of the skin. This can be done with pieces of Webril or gauze cut to the appropriate length.

Following placement of padding between the fingers and toes in self-made splints, use a stockinette over the skin as the first protective layer (see Fig. 50.5 , step 2 ). Extend the stockinette at least 10 to 15 cm beyond the area to be splinted at both ends of the extremity. Later, after the plaster has been applied, fold the stockinette back over the ends of the splint to create smooth, padded rims and to help hold the splint in place when applying elastic bandages (see Fig. 50.5 , step 7 ). To avoid pressure damage, do not pull the stockinette too tightly over bony prominences such as the heel. In addition, prevent wrinkling over flexion creases by slitting and overlapping the stockinette at bony prominences. One may also use two separate pieces of stockinette (one at each end of the splint) to produce the smooth padded rims. As a general rule, use 3-inch-wide stockinette for the upper extremity and 4-inch-wide stockinette for the lower extremity.

After the stockinette has been properly positioned, wrap Webril around the entire area that will be exposed to plaster. Apply at least two or three layers of Webril, with each turn overlapping the previous turn by 25% to 50% of its width (see Fig. 50.5 , step 3 ). Make sure that the Webril extends 2.5 to 5.0 cm beyond the ends of the splint so that it, too, can be folded back over the splint to help create smooth, well-padded edges. Place extra padding over areas of bony prominence, such as the radial condyle or the malleoli ( Box 50.2 ). Although this can be done with Webril, Mother's Cotton adds an additional measure of protection without the worry of wrinkling or ischemic injury. If significant swelling is anticipated, use three or four layers of Webril. Be careful to avoid wrinkling because this can result in significant skin pressure when a tight splint is worn for a long period. Prevent wrinkles by proportionately stretching or even tearing the side of the Webril that must wrap around the larger portion of an extremity. Joints that must be immobilized in a 90-degree position, such as the ankle, make continuous Webril wrapping difficult. To avoid wrinkles around the ankle, place the joint in the proper position before padding. Wrap the Webril around the malleolar and midtarsal regions first, and then cover the bare calcaneal region with overlapping vertical and horizontal Webril strips until the entire heel region is evenly padded. Use the same approach in similar areas such as the elbow. Choose a width of Webril appropriate for the extremity to be splinted. In general, use the 2-inch width for the hands and feet, the 3- or 4-inch width for the upper extremity, and the 4- or 6-inch width for the lower extremity.

A final caveat when using Webril is to be aware of the potential for ischemic injury. This rare complication is most likely to occur in an extremity that continues to have significant swelling after the patient is released from the ED. Ischemia may result because the concentrically placed Webril can become a constricting band. If this situation is anticipated, it can easily be prevented. Cut through the Webril along the side of the extremity that is opposite the plaster splint. Then, secure the splint to the extremity in the usual manner. Alternatively, place two or three layers of Webril (the same diameter as the plaster) directly over the wet plaster (see Fig. 50.6 ). Position the Webril-lined splint over the area to be immobilized and secure it in place with an elastic bandage.

Plaster Preparation

The choice of plaster setting time depends on the nature of the injury and the expertise of the clinician. Use extra-fast–setting plaster when rapid hardening is desired to help maintain alignment of an acutely reduced fracture. However, for the majority of ED splints, plaster with slower setting times (e.g., Specialist Plaster Bandage Fast Setting, BSN Medical) is recommended. Plaster that sets more slowly is easier for some clinicians to use because it affords more leeway in applying and molding the splint. Furthermore, plaster with a longer setting time produces less heat, thus reducing both patient discomfort and the risk for serious burns. Table 50.1 lists the setting times for commonly used plaster. These setting times can be adjusted by adding different substances to the plaster during the production process ( Box 50.3 ). Given plaster with equal setting times, the most important variable affecting the rate of crystallization is water temperature. Warm water hardens a splint faster than cold water does and should not be used when extra time is needed for splint application.

The ideal length and width of plaster depend on the body part to be splinted and the degree of immobilization required. The best way to estimate length is to lay the dry splint next to the area to be splinted. It is best to use a generous length because wet plaster shrinks slightly from its dry length. In addition, if the wet splint is too long, the ends can be folded back easily. Plaster width varies according to the type of splint being made and the body part that is injured, but generally, it should be slightly greater than the diameter of the limb to be splinted. Specific recommendations regarding splint length and width are discussed in the sections describing individual splints.

The thickness of a splint depends on the size of the patient, the extremity that is injured, and the desired strength of the final product. An ankle splint may crack quickly and become useless if only eight layers are used, but this thickness may be ideal for a wrist splint. In general, it is best to use the minimum number of layers necessary to achieve adequate strength. Thicker splints are heavier and more uncomfortable. It is also important to note that plaster thickness is a major determinant of the amount of heat given off during the setting process. More than 12 sheets of plaster create an increased risk for significant burns, especially when using extra-fast–drying plaster, when using dipping water with a temperature higher than 24°C, or when a pillow is placed under or around the extremity for support during the setting process ( Box 50.4 ). For an average-sized adult, splint the upper extremities with 8 sheets of plaster and the lower extremities with 12 to 15 sheets. Such layering usually provides the strength necessary for adequate immobilization while reducing the patient's discomfort and the risk for significant burns. In a 136-kg (300-lb) patient, however, up to 20 layers may be required to make a durable ankle splint.

Keep the dipping water clean and fresh. Reusing water that has been used previously for wetting plaster increases the amount of heat given off during crystallization and causes the plaster to set more quickly. As a rule of thumb, keep the temperature of the water at approximately 24°C. This temperature allows a workable setting time and has not been associated with increased risk for significant burns. As the temperature of the dipping water approaches 40°C, the potential for serious burns increases, even with splint thicknesses consisting of fewer than 12 plies. It is interesting to note that water temperature has been shown to be only a minor consideration in heat production in some studies (see Box 50.4 ).

Splint Application (see Fig. 50.5 )

Completely submerge the dry splint in the water bucket until the bubbling stops. Remove the splint and gently squeeze out excess water until the plaster has a wet and sloppy consistency. Place the splint on a hard table or countertop (a protective covering is recommended to prevent water or plaster damage) and smooth out the splint (with gloved hands) to remove any wrinkles and ensure uniform lamination of all layers. Lamination helps increase the final strength of the splint. Position the splint over the Webril and gently smooth it over the extremity. Plaster is usually somewhat adherent to Webril, but an assistant may be required to hold the splint in place during positioning. Once the splint has been properly positioned over the extremity, fold back the underlying stockinette and Webril to help hold it in place. Secure the splint with an appropriately sized elastic bandage by wrapping in a distal-to-proximal direction. Finally, place the extremity in the desired position and mold the wet plaster to the contour of the extremity with only the palms of the hand. Finger indentations may cause ridges, which can produce pressure points.

Molding the wet splint to conform to the body's anatomy is probably the most important, yet the most frequently overlooked step to ensure adequate immobilization. The act of molding may cause some pain, so be sure to forewarn the patient. Mold with the palm or flat side of the fingers to avoid putting ridges or indentations in the underlying plaster. Complete all manipulation of the wet plaster before it reaches a thick, creamy consistency. Any movement after this time, which is known as the critical period, results in an imperfect crystalline network of calcium sulfate molecules and greatly weakens the ultimate strength of the splint. While the plaster is setting, do not wrap a pillow or blanket around the extremity for support because this leads to inadequate ventilation around the splint and greatly increases the amount of heat produced (see Box 50.4 ).

If an elastic bandage is applied directly over wet plaster, it may be incorporated into the drying plaster, thus making subsequent removal of the bandage difficult. To make it easier for patients to remove and reapply the splint, wrap a single layer of Webril or roll gauze around the wet plaster loosely before applying the elastic bandage. This prevents the wet plaster from becoming stuck to the elastic bandage. Use only one layer of Webril over the plaster because multiple layers are associated with high drying temperatures.

Before the patient is released from the ED, check the extremity for adequate immobilization and evaluate the patient for any evidence of vascular compromise or significant discomfort. If either occurs, loosen the elastic bandage. If the discomfort persists, place additional padding over the painful areas. If this measure, too, is unsuccessful, make a new splint while paying special attention to proper molding so that the wet plaster does not become indented. By resting tender tissue, splinting usually relieves the discomfort quickly, and patients generally say that they feel better soon after the splint has been applied. In general, a splint should decrease the patient's pain, not increase it; hence, do not readily release a patient who complains of increased pain after a splint has been placed. Such complaints may be due to manipulation during splinting, but increased pain should be further addressed or explained.

After a properly fitting, comfortable splint has been applied, place two strips of tape along each side of the splint to prevent the elastic bandage from slipping. It is also prudent to place tape over any metal fasteners used to secure the elastic bandages because these objects can fall off and be swallowed or aspirated by infants and small children. Use enough tape to include the entire circumference of the area under the fasteners, not just small pieces of tape that may not adhere to the moist splint. Finally, provide a sling for patients with upper extremity injuries and, if required, crutches (and instructions for their proper use) for those with lower extremity injuries.

Patient Instructions

Give patients both verbal and written instructions on splint care and precautions. Stress the importance of elevation in helping to decrease pain and swelling. Demonstrate this as well because most patients do not understand the medical definition of elevation. At night, wrap and secure a pillow around the injured extremity to help the patient keep it satisfactorily elevated. If the injury is less than 24 hours old, encourage the application of ice bags or cold packs. It is useless to apply cold packs over plaster, but it can be beneficial to apply them over Webril or an elastic bandage directly over an injury. It may be necessary to remove the splint to ice the injury. In theory, cold therapy stiffens collagen and thus reduces the tendency for ligaments and tendons to deform. Cold therapy also decreases muscle spasm and excitability, reduces blood flow (thereby limiting hemorrhage and edema), raises the pain threshold, and decreases inflammation. Because the thermal conductivity of subcutaneous tissue is poor, apply cold packs for at least 30 minutes at a time. This guideline is in contrast to the popular recommendation of “ice 20 minutes on, 20 minutes off,” which often does nothing more than cool the skin. Do not use cold packs for more than the first 24 to 48 hours because cold can interfere with long-term healing. Instruct the patient to not stress the splint for at least 24 hours because plaster does not approach optimal strength until evaporation has reduced the water content of the plaster to approximately 21% of its initial hydrated level. This process of removing excess water by evaporation is called curing , and it generally takes several days to be completed. However, by 24 hours the water content of the plaster has usually been reduced enough to produce a strong, resilient splint. In addition, because the chemical process involved in the formation of plaster is reversible, the patient should avoid getting the splint wet. If the injury permits, the splint can be removed for showering and then reapplied. Alternatively, one or more plastic bags may be placed over a splint before showering.

Splints may crack, break, or disintegrate with wear, and a useless splint should be removed or replaced. Give patients general guidelines for length of immobilization and appropriate follow-up care. Avoid long-term immobilization, particularly in the elderly, because this can produce permanent disability. It is extremely important for the patient to continue to check for signs of vascular compromise. If the patient experiences a significant increase in pain, numbness or tingling of the digits, pallor of the distal end of the extremity, decreased capillary refill, or weakness, instruct the patient to return to the ED or to see his or her primary clinician without delay. As with casting, increased pain after splinting is a warning sign that should prompt a return visit, not telephone advice. Avoid giving excessive doses of opioids during the first 2 to 3 days after splinting to allow pain to prompt a follow-up visit.

Long Arm Splints

Long Arm Posterior Splint

Indications.

Use a long arm posterior splint ( Figs. 50.8 and 50.9 ) to immobilize injuries to the elbow and proximal end of the forearm. It completely eliminates flexion and extension of the elbow but does not entirely prevent pronation and supination of the forearm. Therefore it is not recommended for immobilization of complex or unstable distal forearm fractures unless used in conjunction with a long arm anterior splint (see later in this section). Alternatively, a double “sugar-tong” splint can be applied (see later in this section).

Construction.

Construct a long arm posterior splint with 8 to 10 layers of 4- or 6-inch-wide plaster. Start the splint on the posterior aspect of the proximal end of the arm. Extend it down the arm to the elbow and then along the ulnar aspect of the forearm and hand to the level of the metacarpophalangeal (MCP) joints.

Application.

Apply a stockinette and Webril as described previously. Cut a hole in the stockinette to expose the thumb, and place extra padding over the olecranon to prevent pressure injury. Position the arm with the elbow flexed to 90 degrees, the forearm neutral (thumb upward), and the wrist neutral or slightly extended (10 to 20 degrees). Ask an assistant to hold the wet splint in place, particularly when applying both a posterior and an anterior splint. Once the splint has been properly positioned, fold the ends of the stockinette and Webril back and secure the splint in place with 2-, 3-, or 4-inch elastic bandages. Finally, fold the sides of the splint up to create a gutter configuration and carefully mold the plaster around the extremity with the palms of the hand. The fingers and thumb should remain free to prevent stiffness from unnecessary immobilization.

Double Sugar-Tong Splint

Indications.

Use a double sugar-tong splint ( Fig. 50.10 ) like a long arm posterior splint to immobilize injuries to the elbow and forearm. However, because it prevents pronation and supination of the forearm, it is preferable for some distal forearm and elbow fractures.

Construction.

The splint consists of two separate pieces of plaster, a forearm splint and an arm splint. Construct each piece with eight layers of 3- or 4-inch plaster. The forearm portion of the splint runs from the metacarpal heads on the dorsum of the hand along the dorsal surface of the forearm around the elbow. It continues along the volar surface of the forearm to the palm of the hand and stops at the level of the MCP joints. The arm portion of the splint begins on the anterior aspect of the proximal end of the humerus. It runs down the arm over the forearm splint and around the elbow. It then continues up the posterior aspect of the arm, once again going over the forearm splint, until it reaches the starting point.

Application.

Use a stockinette, Webril, and positioning similar to the way described for the application of a long arm posterior splint. Secure the two splints in place with 2-, 3-, or 4-inch elastic bandages starting with the forearm splint at the hand. Once the forearm splint is secured in place, wrap the arm portion of the splint beginning at its proximal end. Keep the patient's fingers and thumb free to prevent stiffness.