Splinting Processes, Tools, and Techniques

CHAPTER 3


Splinting Processes, Tools, and Techniques





Splinting requires knowledge of a variety of processes, tools, and techniques. This chapter reviews commonly used processes, tools, and techniques related to splinting. Splints and their purposes needed to address a variety of clients who require custom-made or prefabricated splint intervention are discussed. This chapter also outlines how PAMs may be used to prepare a client for optimal positioning during the splinting process.



Thermoplastic Splinting Materials


Low-temperature thermoplastic (LTT) materials are the most commonly used to fabricate splints. The materials are considered “low temperature” because they soften in water heated between 135° and 180°F and the therapist can usually safely place them directly against a person’s skin while the plastic is still moldable. These compare to high-temperature thermoplastics that become soft when warmed to greater than 250°F and cannot touch a person’s skin while moldable without causing a thermal injury. When LTT is heated, it becomes pliable, and then hardens to its original rigidity after cooling. The first commonly available low-temperature thermoplastic material was Orthoplast. Currently, many types of thermoplastic materials are available from several companies. Types of materials used in clinics vary on the basis of patient population, diagnoses, therapists’ preferences, and availability.


In addition to splint use, LTT material is commonly used to adapt devices for improving function. For example, thermoplastic material may be heated and wrapped around pens, handles, utensils, and other tools to build up the circumference and decrease the required range of motion needed to use such items.


Decisions regarding the best type of thermoplastic material to use for splint fabrication must be made. Decisions are based on such factors as cost, properties of the thermoplastic material, familiarity with splinting materials, and therapeutic goals. One type of thermoplastic material is not the best choice for every type or size of splint. If a therapist has not had experience with a particular type of thermoplastic material, it is beneficial to read the manufacturer’s technical literature describing the material’s content and properties. Therapists should practice using new materials before fabricating splints on clients.



Thermoplastic Material Content and Properties


Thermoplastic materials are elastic, plastic, a combination of plastic and rubberlike, and rubberlike [North Coast Medical 2006]. Thermoplastic materials that are elastic based have some amount of memory. (Memory is addressed in the properties discussion of this section.) Typically, elastic thermoplastic has a coating to prevent the material from adhering to itself. (Most thermoplastics have a nonstick coating, but there are a few that specify they do not.) Elastic materials have a longer working time than other types of materials and tend to shrink during the cooling phase.


Thermoplastics with a high plastic content tend to be drapable and have a low resistance to stretch. Plastic-based materials are often used because they result in a highly conforming splint. Such plastic requires great skill in handling the material (e.g., avoiding fingerprints and stretch) during heating, cutting, moving, positioning, draping, and molding. Thus, for novice splinters positioning the client in a gravity-assisted position is best to prevent overstretching of the material.


Thermoplastic materials described as rubbery or rubberlike tend to be more resistant to stretching and fingerprinting. These materials are less conforming than their drapier plastic counterparts. Therapists should not confuse resistance to stretch during the molding process with the rigidity of the splint upon completion. Materials that are quite drapey become extremely rigid when cooled and set, and the opposite is also true. In addition, the more contours a splint contains the more rigid it will be.


Some LTT materials are engineered to include an antimicrobial protection. Splints can create a moist surface on the skin where mold and mildew can form [Sammons et al. 2006]. When skin cells and perspiration remain in a relatively oxygen-free environment for hours at a time, it is conducive to microbe growth and results in odor. Daily isopropyl alcohol cleansing of the inside surface of the splint will effectively combat this problem. Splinting materials containing the antimicrobial protection offer a defense against microorganisms. The antimicrobial protection does not wash or peel off.


Each type of thermoplastic material has unique properties [Lee 1995] categorized by handling and performance characteristics. Handling characteristics refer to the thermoplastic material properties when heated and softened, and performance characteristics refer to the thermoplastic material properties after the material has cooled and hardened.



Handling Characteristics



Memory


Memory is a property that describes a material’s ability to return to its preheated (original) shape, size, and thickness when reheated. The property ranges from 100% to little or no memory capabilities [North Coast Medical 1999]. Materials with 100% memory will return to their original size and thickness when reheated. Materials with little to no memory will not recover their original thickness and size when reheated.


Most materials with memory turn translucent (clear) during heating. Using the translucent quality as an indicator, the therapist can easily determine that the material is adequately heated and can prevent over- or underheating. The ability to see through the material also assists the therapist to properly position and contour the material on the client.


Memory allows therapists to reheat and reshape splints several times without the material stretching excessively. Materials with memory must be constantly molded throughout the cooling process to sustain maximal conformability to persons. Novice or inexperienced therapists who wish to correct errors in a poorly molded splint frequently use materials with memory. Material with memory will accommodate the need to redo or revise a splint multiple times while using the same piece of material over and over. LTT material with memory is often used to make splints for clients who have high tone or stiff joints, because the memory allows therapists to adjust or serially splint a joint(s) into a different position. Clinicians use a serial splinting approach when they intermittently remold to a person’s limb to accommodate changes in range of motion.


Materials with memory may pose problems when one is attempting to make fine adjustments. For example, spot heating a small portion may inadvertently change the entire splint because of shrinkage. Therapists must carefully control duration of heat exposure. It may be best in these situations to either reimmerse the entire splint in water and repeat the molding process or prevent the problem and select a different type of LTT material.



Drapability


Drapability is the degree of ease with which a material conforms to the underlying shape without manual assistance. The degree of drapability varies among different types of material. The duration of heating is important. The longer the material heats the softer it becomes and the more vulnerable it becomes to gravity and stretch. When a material with drapability is placed on a surface, gravity assists the material in draping and contouring to the underlying surface. Material exhibiting drapability must be handled with care after heating. A therapist should avoid holding the plastic in a manner in which gravity affects the plastic and results in a stretched, thin piece of plastic. Therefore, this type of plastic is best positioned on a clean countertop during cutting. Material with high drapability is difficult to use for large splints and is most successful on a cooperative person who can place the body part in a gravity-assisted position.


Thermoplastic materials with high drapability may be more difficult for beginning splintmakers because the materials must be handled gently and often novice splinters handle the material too aggressively. Successful molding requires therapists to refrain from pushing the material during shaping. Instead, the material should be lightly stroked into place. Light touch and constant movement of therapists’ hands will result in splints that are cosmetically appealing. Materials with low drapability require firm pressure during the molding process. Therefore, persons with painful joints or soft-tissue damage will better tolerate materials with high drapability.




Bonding


Self-bonding or self-adherence is the degree to which material will stick to itself when properly heated. Some materials are coated; others are not. Materials that are coated always require surface preparation with a bonding agent or solvent. Self-bonding (uncoated) materials may not require surface preparation, but some thermoplastic materials have a coating that must be removed for bonding to occur. Coated materials tack at the edges because the coating covers only the surface and not the edges.


Often, the tacked edges can be pried apart after the material is completely cool. If a coated material is stretched, it becomes tackier and is more likely to bond. When heating self-bonding material, the therapist must take care that the material does not overlap on itself during the heating or draping process. If the material overlaps, it will stick to itself. Noncoated materials may adhere to paper towels, towels, bandages, and even the hair on a client’s extremity! Thus, it may be necessary to apply an oil-based lotion to the client’s extremity. To facilitate the therapist’s handling of the material, wetting the hands and scissors with water or lotion can prevent sticking.


All thermoplastic material, whether coated or uncoated, forms stronger bonds if surfaces are prepared with a solvent or bonding agent (which removes the coating from the material). A bonding agent or solvent is a chemical that can be brushed onto both pieces of the softened plastic to be bonded. In some cases, therapists roughen the two surfaces that will have contact with each other. This procedure, called scoring, can be carefully done with the end of a scissors, an awl, or a utility knife. After surfaces have been scored, they are softened, brushed with a bonding agent, and adhered together. Self-adherence is an important characteristic for mobilization splinting when one must secure outriggers to splint bases (see Chapter 11) and when the plastic must attach to itself to provide support—for example, when wrapping around the thumb as in a thumb spica splint (see Chapter 8).




Other Considerations


Other handling characteristics to be considered are heating time, working time, and shrinkage. The time required to heat thermoplastic materials to a working temperature should be monitored closely because material left too long in hot water may become excessively soft and stretchy. Therapists should be cognizant of the temperature the material holds before applying it to a person’s skin to prevent a burn or discomfort. After material that is image inch thick is sufficiently heated, it is usually pliable for approximately 3 to 5 minutes (S. Berger, personal communication, 1995). Some materials will allow up to 4 to 6 minutes of working time. Materials thinner than image inch and those that are perforated heat and cool more quickly.


Shrinkage is an important consideration when therapists are properly fitting any splint, but particularly with a circumferential design. Plastics shrink slightly as they cool. During the molding and cooling time, precautions should be taken to avoid a shrinkage-induced problem such as difficulty removing a thumb or finger from a circumferential component of a splint.



Performance Characteristics







Perforations


Theoretically, perforations in material allow for air exchange to the underlying skin. Various perforation patterns are available (e.g., mini-, maxi-, and micro-perforated) [PSR 2006]. Perforated materials are also designed to reduce the weight of splints. Several precautions must be taken if one is working with perforated materials [Wilton 1997]. Perforated material should not be stretched because stretching will enlarge the holes in the plastic and thereby decrease its strength and pressure distribution. When cutting a pattern out of perforated material, therapists should attempt to cut between the perforations to prevent uneven or sharp edges. If this cannot be avoided, the edges of the splint should be smoothed.



Finish, Colors, and Thickness


Finish refers to the texture of the end product. Some thermoplastics have a smooth finish, whereas others have a grainy texture. Generally, coated materials are easier to keep clean because the coating resists soiling [McKee and Morgan 1998].


The color of the thermoplastic material may affect a person’s acceptance and satisfaction with the splint and compliance with the wearing schedule. Darker-colored splints tend to show less soiling and appear cleaner than white splints. Brightly colored splints tend to be popular with children and youth. Colored materials may be used to help a person with unilateral neglect call attention to one side of the body [McKee and Morgan 1998]. In addition, colored splints are easily seen and therefore useful in preventing loss in institutional settings. For example, it is easier to see a blue splint in white bed linen than to see a white splint in white bed linen.


A common thickness for thermoplastic material is image inch. However, if the weight of the entire splint is a concern a thinner plastic may be used—reducing the bulkiness of the splint and possibly increasing the person’s comfort and improving compliance with the wearing schedule. Some thermoplastic materials are available in thicknesses of 1/16, 3/32, and 3/16 inch. Thinner thermoplastic materials are commonly used for small splints and for arthritis and pediatric splints, whereas the 3/16-inch thickness is commonly used for lower extremity splints and fracture braces [Melvin 1989, Sammons et al. 2006]. Therapists should keep in mind that plastics thinner than image inch will soften and harden more quickly than thicker materials. Therefore, therapists who are novices in splinting may find it easier to splint with image-inch-thick materials than with thinner materials [McKee and Morgan 1998].Table 3-1 lists property guidelines for thermoplastic materials. (See also Laboratory Exercise 3-1.)





Process: Making the Splint



Splint Patterns


Making a good pattern for a splint is necessary for success. Giving time and attention to the making of a well-fitting pattern will save the splintmaker’s time and materials involved in making adjustments or an entirely new splint. A pattern should be made for each person who needs a splint. Generic patterns rarely fit persons correctly without adjustments. Having several sizes of generic patterns cut out of aluminum foil for trial fittings may speed up the pattern process. A standard pattern can be reduced on a copy machine for pediatric sizes.


To make a custom pattern, the therapist traces the outline of the person’s hand (or corresponding body part) on a paper towel (or foil), making certain that the hand is flat and in a neutral position. If the person’s hand is unable to flatten on the paper, the contralateral hand may be used to draw the pattern and fit the pattern. If the contralateral hand cannot be used, the therapist may hold the paper in a manner so as to contour to the hand position. The therapist marks on the paper any hand landmarks needed for the pattern before the hand is removed. The therapist then draws the splint pattern over the outline of the hand, cuts out the pattern with scissors, and completes final sizing.



Fitting the Pattern to the Client


As shown inFigure 3-1, moistening the paper and applying it to the person’s hand helps the therapist determine which adjustments are required. Patterns made from aluminum foil work well to contour the pattern to the extremity. If the pattern is too large in areas, the therapist can make adjustments by marking the pattern with a pen and cutting or folding the paper. Sometimes it is necessary to make a new pattern or to retrace a pattern that is too small or that requires major adjustments. The therapist ensures that the pattern fits the person before tracing it onto and cutting it out of the thermoplastic material. It is well worth the time to make an accurate pattern because any ill-fitting pattern directly affects the finished product.



Throughout this book, detailed instructions are provided for making different splint patterns. One should keep in mind that therapists with experience and competency may find it unnecessary to identify all landmarks as indicated by the detailed instructions. Form 3-1 lists suggestions helpful to a beginning splintmaker when drawing and fitting patterns.



FORM 3-1   *Hints for Drawing and Fitting a Splint Pattern




image Explain the pattern-making process to the person.


image Ask or assist the person to remove any jewelry from the area to be splinted.


image Wash the area to be splinted if it is dirty.


image If splinting over bandages or foam, cover the extremity with stockinette or a moist paper towel to prevent the plastic from sticking to the bandages.


image Position the affected extremity on a paper towel in a flat, natural resting position. The wrist should be in a neutral position with a slight ulnar deviation. The fingers should be extended and slightly abducted.


image To trace the outline of the person’s extremity, keep the pencil at a 90-degree angle to the paper.


image Mark the landmarks needed to draw the pattern before the person removes the extremity from the paper.


image For a more accurate pattern, the paper towel can be wet and placed on the area for evaluation of the pattern, or aluminum foil can be used.


image Folding the paper towel to mark adjustments in the pattern can help with evaluation of the pattern.


image When evaluating the pattern fit of a forearm-based splint on the person, look for the following:



image When tracing the pattern onto the thermoplastic material, do not use an ink pen because the ink may smear when the material is placed in the hot water to soften. Rather, use a pencil, grease pencil, or awl to mark the pattern outline on the material.



*See Appendix B for a perforated copy of this form.



Tracing, Heating, and Cutting


After making and fitting the pattern to the client, the therapist places it on the sheet of thermoplastic material in such a way as to conserve material and then traces the pattern on the thermoplastic material with a pencil. (Conserving materials will ultimately save expenses for the clinic or hospital.) Pencil lines do not show up on all plastics. Using an awl to “scratch” the pattern outline on the plastics works well. Another option is to use grease pencils or china pencils. Caution should be taken when a therapist uses an ink pen, as the ink may smear onto the plastic. However, the ink may be removed with chlorine.


Once the pattern is outlined on a sheet of material, a rectangle slightly larger than the pattern is cut with a utility knife (Figure 3-2). After the cut is made, the material is folded over the edge of a countertop. If unbroken, the material can be turned over to the other side and folded over the countertop’s edge. Any unbroken line can then be cut with a utility knife or scissors.




Heating the Thermoplastic Material


Thermoplastic material is softened in an electric fry pan, commercially available splint pan, or hydrocollator filled with water heated to approximately 135° to 180°F (Figure 3-3). (Some materials can be heated in a microwave oven or in a fry pan without water.) To ensure temperature consistency, the temperature dial should be marked to indicate the correct setting of 160°F by using a hook-and-loop (Velcro) dot or piece of tape. When softening materials vertically in a hydrocollator, the therapist must realize the potential for problems associated with material stretching due to gravity’s effects. If a fry pan is used, the water height in the pan should be a minimum of three-fourths full (approximately 2 inches deep).



Adequate water height allows a therapist to submerge portions of the splint later when making adjustments. If the thermoplastic material is larger than the fry pan, a portion of the material should be heated. When the material is soft, a paper towel is placed on the heated portion and the rest of the material is folded on the paper towel. A nonstick mesh may be placed in the bottom of a fry pan to prevent the plastic from sticking to any materials or particles. However, it can create a mesh imprint on the plastic. When the thermoplastic piece is large (and especially when it is a high-stretch material), it is a great advantage to lift the thermoplastic material out of the splint pan on the mesh. This keeps the plastic flat and minimizes stretch.



Cutting the Thermoplastic Material


After removing the thermoplastic material from the water with a spatula or on the mesh, the therapist cuts the material with either round- or flat-edged scissors (Figure 3-4). The therapist uses sharp scissors and cuts with long blade strokes (as opposed to using only the tips of the scissors). Scissors should be sharpened at least once each year, and possibly more often, depending on use. Dedicating scissors for specific materials will prolong the edge of the blade. For example, one pair of scissors should be used to cut plastic, another for paper, another for adhesive-backed products, and so on. Sharp scissors in a variety of sizes are helpful for difficult contoured cutting and trimming. Splinting solvent or adhesive removers will remove adhesive that builds up on scissor blades.





Positioning the Client for Splinting


There are several client positioning options. The client is placed in a position that is comfortable, especially for the shoulder and elbow. A therapist may use a gravity-assisted position for hand splinting by having the person rest the dorsal wrist area on a towel roll while the forearm is in supination to maintain proper wrist positioning. Alternatively, a therapist may ask the person to rest the elbow on a table and splint the hand while it is in a vertical position.


For persons with stiffness, a warm water soak or whirlpool, ultrasound, paraffin dip, or hot pack can be used before splinting. Splinting is easiest when persons take their pain medication 30 to 60 minutes before the session. For persons with hypertonicity, it may be effective to use a hot pack on the joint to be splinted. Then the joint should be positioned and splinted in a submaximal range. When splinting is done after warming or after a treatment session, the joints are usually more mobile. However, the splint may not be tolerated after the preconditioning effect wears off. Thus, the therapist must find a balance to complete a gentle warm-up and avoid aggressive preconditioning treatments [personal communication, K. Schultz-Johnson, 1999]. Goniometers are used, when possible, to measure joint angles for optimal therapeutic positioning.



Molding the Splint to the Client


Once positioning is accomplished, the therapist retrieves the softened thermoplastic material. Any hot water is wiped off on a paper towel, a fabric towel, or a pillow that has a dark-colored pillowcase on it. (The dark-colored pillowcase helps identify any small scraps or snips of material from previous splinting activities that may adhere to the thermoplastic material.) The therapist checks the temperature of the softened plastic and finally applies the thermoplastic material to the person’s extremity. The thermoplastic material may be extremely warm, and thus the therapist should use caution to prevent skin burn or discomfort. For persons with fragile skin who are at risk of burns, the extremity may be covered with stockinette before the splinting material is applied. Some thermoplastic materials will stick to hair on the person’s skin, but this situation can be avoided by using stockinette or lotion on the skin before application of the splinting material.


Therapists may choose to hasten the cooling process to maintain joint position and splint shape. Several options are available. First, a therapist can use an environmentally friendly cold spray. Cold spray is an agent that serves as a surface coolant. Cold spray should not be used near persons who have severe allergies or who have respiratory problems. Because the spray is flammable, it should be properly stored. A second option is to dip the person’s extremity with the splint into a tub of cold water. This must be done cautiously with persons who have hypertonicity because the cold temperature could cause a rapid increase in the amount of tone, thus altering joint position. Similar to using a tub of cold water, the therapist may carefully walk the person wearing the splint to a sink and run cold water over the splint. Third, a therapist can use frozen Theraband and wrap it around the splint to hasten cooling. An Ace bandage immersed in ice water and then wrapped around the splint may also speed cooling [Wilton 1997]. However, Ace bandages often leave their imprints on the splinting material.

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Mar 13, 2017 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Splinting Processes, Tools, and Techniques

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