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Low-profile Dorsal Dynamic Wrist-Finger-Thumb Assistive-extension Orthosis for High Radial Nerve Injury—Fabrication Instructions
SCIENTIFIC/CLINICAL ARTICLES
Low-profile Dorsal Dynamic Wrist-FingerThumb Assistive-extension Orthosis for High Radial Nerve Injury—Fabrication Instructions Pat McKee, MSc, OT Reg (Ont.) Department of Occupational Science and Occupational Therapy, University of Toronto, Toronto, Ontario, Canada
Cecilia Nguyen, BScOT, OT Reg (Ont.) Occupational Therapist, Holland Orthopaedic & Arthritic Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
INTRODUCTION The purpose of this article is to provide technical support to the preceding article by giving details for the fabrication of this unique splint (orthosis).
Objectives
d
d d d d d d d
d d
Indications
d d
To enhance hand dexterity by compensating for weak/paralyzed muscles—passively extend the wrist, metacarpophalangeal joints (MCPs), and finger proximal interphalangeal joints (PIPs) to 08 while permitting full active wrist and digit flexion To prevent overstretching of denervated extensor muscles To prevent shortening of unopposed innervated flexor muscles To prevent flexion contractures To maintain tendon and nerve glide To enable joint motion to optimize joint cartilage nutrition and health1 To prevent the development of maladaptive compensatory/substitution prehension patterns To keep surgically repaired nerve(s) slack to prevent tension that would interfere with nerve healing at suture site To prevent adverse neural tension in the regenerating nerve2 To prevent perpetual flexed wrist joint position that could compress and irritate the median nerve When the extensors of the wrist, finger MCPs, and thumb are paralyzed or weak High radial nerve injury
Correspondence and reprint requests to Pat McKee, MSc, OT Reg (Ont.), Department of Occupational Science and Occupational Therapy, University of Toronto, 160-500 University Avenue, Toronto, Ontario, Canada M5G 1V7; e-mail:. 0894-1130/$ e see front matter Ó 2007 Hanley & Belfus, an imprint of Elsevier Inc. All rights reserved. doi:10.1197/j.jht.2006.11.011
70
JOURNAL OF HAND THERAPY
Materials
d
d d d
d d d d d d
d
Equipment and tools
d d d d d
Patient’s position
d d
Pattern Fabrication
Uncoated (to enable secure bonding), mini-perforated low temperature thermoplastic (LTT), e.g., Aquaplast, Orfit, Orfilight, Redifit Classic—1/12 in (2 mm thick) for average woman’s hand; consider using proportionately thicker or thinner LTT for larger or smaller hand; approximate size 6 in 3 12 in (15 cm 3 30 cm) LTT for dynamic thumb extension piece—approximate size 3 in 3 7 in (7.5 cm 3 15 cm) Four finger slings, 3 in or 3.5 in (7.6 cm or 9 cm) long—washable UltrasuedeÒ is ideal Self-adhesive closed-cell padding, e.g., PlastazoteÒ—1/16 in/1.6 mm—to pad finger metacarpal (MC) heads and dorsal wrist; and to line finger cuffs Self-adhesive hook VelcroÒ Loop VelcroÒ Strap pads Medium (1/4 in/6.4 mm) wide thermoplastic tube—two pieces each approximately 1 in/2.5 cm long Four grommets or small thermoplastic tubes to line the excursion holes Covered elastic cord, 0.05 in (1.2 mm) thick, available from fabric store or rehabilitation catalog—four pieces each about 8 in (20 cm) long and four pieces each about 4 in (10 cm) long Optional materials: stretchy velour fabric (washable); ultra-thin, waterproof foam tape for covering edges Heat gun or other form of dry heat if splint is lined with fabric (e.g., dry heat oven or microwave oven) butane torch (optional but helpful) scissors hole punch lipstick Seated with the forearm pronated for gravity-assisted molding at a comfortable work height for the therapist Position the wrist in slight extension and neutral deviation
Orthotic base: 1. Apply padding to the finger MC heads and across the dorsum of the wrist. 2. Optional bonding of fabric (unpublished technique developed by Margareta Persson of Sweden): a. Cut out the LTT base, place on top of fabric and heat with heat gun until LTT is thoroughly heated and adhering to the fabric. b. Alternate microwave oven heating: Position LTT on top of fabric then place in a microwave oven with fabric side down. Heat until LTT is thoroughly heated and adhering to the fabric. c. Cut off the excess fabric around the edges. 3. Reheat if necessary until fully malleable. Ensure that the LTT is not too hot on the patient’s skin—check on an area with intact sensation. 4. Mold the LTT base, positioning the distal edge at the distal interphalangeal joint creases, holding fingers in extension and wrist in desired amount of extension and neutral deviation. 5. When the contours have set, transfer the padding from the patient’s skin to the inside of the splint (see Fig. 6c). 6. Attach the forearm straps, including strap pads if desired. 7. To create the palmar strap reinforcement (PSR), dry heat the thermoplastic tubes with a heat gun or butane torch and adhere to the splint base between wrist and MCP joints, taking care to maintain the central tunnel of the tubes. Note: The use of wet heat will not ensure a secure bond of the tubes to the splint base. 8. To ensure that the LTT will bend to allow wrist flexion, minimize the width and contours of the LTT over the dorsum of the hand. Reinforced palmar strap 1. Apply a piece of self-stick hook VelcroÒ (1 in 3 2 in/2.5 cm 3 5 cm) over the tubes (see Fig. 6d). 2. Cut a piece of 1-in (2.5-cm) wide loop VelcroÒ long enough for a palmar strap that attaches to this hook VelcroÒ. 3. To create the palmar strap reinforcement (PSR), dry heat a piece of LTT (PSR in Figure 1), adhere to the plush side of the palmar strap and mold to the contours of the transverse palmar arch. 4. Optional: cover edges with foam tape as needed for comfort (see Fig. 6f). Finger extension assists 1. Mark the dorsal center of each middle phalanx with a dot of lipstick. 2. Apply the splint, secure with straps, then passively extend the fingers, to carefully and accurately transfer the lipstick mark to the LTT. 3. Punch holes through the LTT at the location of the lipstick marks. To ensure that the cords do not fray with friction going through the holes, reinforce each hole with a metal grommet or a thermoplastic tube (see Fig. 6d). 4. To prevent tearing of the finger slings, even when the holes are reinforced with a metal grommet, consider reinforcing the holes with LTT as follows. Dry heat a small piece of uncoated LTT, adhere it over holes then punch a new hole through the LTT (see Fig. 9). 5. Securely tie an 8-in (20-cm) elastic cord to each finger cuff using a bowline knot. Numerous Web sites demonstrate how to make knots. For example, check out www.animatedknots.com. Thread each cord through a hole in the splint base, then thread two cords through each tube. Another method to ensure that a knot does not become untied is to apply nail polish over a simple knot. 6. Use a 4-in (10-cm) long cord to create a tension adjuster around one cord coming through the tubes, using a girth hitch knot (Figure 2). Tighten the knot. 7. Line finger cuffs with thin self-adhesive padding (e.g., PlastazoteÒ) to prevent migration and stretching of the cuffs and to provide sufficient stiffening to prevent them from collapsing when applying the splint. 8. Apply splint and adjust tension in each elastic finger cord by sliding the tension adjuster proximally or distally. 9. Optional: use different color cords to help distinguish the cord attached to the finger cuff (e.g., white) from the tension adjustor cord (e.g., black). Alternatively, distinguish the cords with different colors of highlighter pens.
JanuaryeMarch 2007
71
Wearing regimen
Splint care
Precautions and patient education
Options
Thumb extension assist (see Fig. 6d) 1. Mold the thermoplastic around the thumb, overlapping the thermoplastic dorsally and ensure a secure bond with no crevices. 2. Determine the appropriate location for a loop VelcroÒ strap to optimally position the thumb in extension/ abduction. 3. Apply hook VelcroÒ to the thermoplastic thumb component and another piece to the forearm base. 4. To ensure that the hook VelcroÒ will not peel off the base, melt about 1/8 in (3.2 mm) of the hooks (using dry heat from a heat gun or butane torch) from the vulnerable edge of each patch of hook VelcroÒ. 5. Attach the loop VelcroÒ strap with sufficient tension to extend/abduct the thumb but loose enough to allow finger opposition. d During functional activities. d For some social situations, a simple wrist splint—custom or prefabricated—might be preferred. d For night, a wrist splint or wrist-hand splint can be worn. d Advise patient how to clean the splint. Extra attention to careful cleansing is needed if the splint is lined. Margareta Persson suggests placing the splint in a lingerie bag and washing in cold water on a gentle cycle in a washing machine. Mrs. M. hand-washed the splint with DoveÒ Daily Hydrating Cleansing Cloths. Allow to air dry. d Patient lacks sensation through radial nerve distribution, thus check carefully for skin irritation before patient leaves the clinic. d Teach patient to look for red marks and instruct patient to return to clinic for adjustments if signs of irritation are observed. d Thumb component can be excluded if palmar abduction is sufficient to allow functional thumb motion. d Modify the design to exclude the forearm base (i.e., convert to hand-based design) when wrist extension does not need assistance (see Fig. 11). d Exclude fabric lining and provide a stockinette sleeve to wear under the splint.
FIGURE 2. Girth hitch knot used to create a tension adjuster on the elastic cord attached to each finger cuff.
REFERENCES
FIGURE 1. Pattern for thermoplastic components of lowprofile dorsal dynamic wristefingerethumb assistiveextension splint. PSR-palmar strap reinforcement. The distal end of the splint is at the distal interphalangeal joint creases. Note the placement of padding adjacent to metacarpal heads and dorsal wrist. 72
JOURNAL OF HAND THERAPY
1. Salter RB. History of rest and motion and the scientific basis for early continuous passive motion. Hand Clin. 1996;12:1–11. 2. Wright TW, Glowczewskie F Jr, Cowin D, Wheeler DL. Radial nerve excursion and strain at the elbow and wrist associated with upper-extremity motion. J Hand Surg [Am]. 2005;30:990–6.
Low-profile Dorsal Dynamic Wrist-FingerThumb Assistive-extension Orthosis for High Radial Nerve Injury—Fabrication Instructions Pat McKee, MSc, OT Reg (Ont.) Department of Occupational Science and Occupational Therapy, University of Toronto, Toronto, Ontario, Canada
Cecilia Nguyen, BScOT, OT Reg (Ont.) Occupational Therapist, Holland Orthopaedic & Arthritic Centre, Sunnybrook Health Sciences Centre, Toronto, Canada
INTRODUCTION The purpose of this article is to provide technical support to the preceding article by giving details for the fabrication of this unique splint (orthosis).
Objectives
d
d d d d d d d
d d
Indications
d d
To enhance hand dexterity by compensating for weak/paralyzed muscles—passively extend the wrist, metacarpophalangeal joints (MCPs), and finger proximal interphalangeal joints (PIPs) to 08 while permitting full active wrist and digit flexion To prevent overstretching of denervated extensor muscles To prevent shortening of unopposed innervated flexor muscles To prevent flexion contractures To maintain tendon and nerve glide To enable joint motion to optimize joint cartilage nutrition and health1 To prevent the development of maladaptive compensatory/substitution prehension patterns To keep surgically repaired nerve(s) slack to prevent tension that would interfere with nerve healing at suture site To prevent adverse neural tension in the regenerating nerve2 To prevent perpetual flexed wrist joint position that could compress and irritate the median nerve When the extensors of the wrist, finger MCPs, and thumb are paralyzed or weak High radial nerve injury
Correspondence and reprint requests to Pat McKee, MSc, OT Reg (Ont.), Department of Occupational Science and Occupational Therapy, University of Toronto, 160-500 University Avenue, Toronto, Ontario, Canada M5G 1V7; e-mail:
70
JOURNAL OF HAND THERAPY
Materials
d
d d d
d d d d d d
d
Equipment and tools
d d d d d
Patient’s position
d d
Pattern Fabrication
Uncoated (to enable secure bonding), mini-perforated low temperature thermoplastic (LTT), e.g., Aquaplast, Orfit, Orfilight, Redifit Classic—1/12 in (2 mm thick) for average woman’s hand; consider using proportionately thicker or thinner LTT for larger or smaller hand; approximate size 6 in 3 12 in (15 cm 3 30 cm) LTT for dynamic thumb extension piece—approximate size 3 in 3 7 in (7.5 cm 3 15 cm) Four finger slings, 3 in or 3.5 in (7.6 cm or 9 cm) long—washable UltrasuedeÒ is ideal Self-adhesive closed-cell padding, e.g., PlastazoteÒ—1/16 in/1.6 mm—to pad finger metacarpal (MC) heads and dorsal wrist; and to line finger cuffs Self-adhesive hook VelcroÒ Loop VelcroÒ Strap pads Medium (1/4 in/6.4 mm) wide thermoplastic tube—two pieces each approximately 1 in/2.5 cm long Four grommets or small thermoplastic tubes to line the excursion holes Covered elastic cord, 0.05 in (1.2 mm) thick, available from fabric store or rehabilitation catalog—four pieces each about 8 in (20 cm) long and four pieces each about 4 in (10 cm) long Optional materials: stretchy velour fabric (washable); ultra-thin, waterproof foam tape for covering edges Heat gun or other form of dry heat if splint is lined with fabric (e.g., dry heat oven or microwave oven) butane torch (optional but helpful) scissors hole punch lipstick Seated with the forearm pronated for gravity-assisted molding at a comfortable work height for the therapist Position the wrist in slight extension and neutral deviation
Orthotic base: 1. Apply padding to the finger MC heads and across the dorsum of the wrist. 2. Optional bonding of fabric (unpublished technique developed by Margareta Persson of Sweden): a. Cut out the LTT base, place on top of fabric and heat with heat gun until LTT is thoroughly heated and adhering to the fabric. b. Alternate microwave oven heating: Position LTT on top of fabric then place in a microwave oven with fabric side down. Heat until LTT is thoroughly heated and adhering to the fabric. c. Cut off the excess fabric around the edges. 3. Reheat if necessary until fully malleable. Ensure that the LTT is not too hot on the patient’s skin—check on an area with intact sensation. 4. Mold the LTT base, positioning the distal edge at the distal interphalangeal joint creases, holding fingers in extension and wrist in desired amount of extension and neutral deviation. 5. When the contours have set, transfer the padding from the patient’s skin to the inside of the splint (see Fig. 6c). 6. Attach the forearm straps, including strap pads if desired. 7. To create the palmar strap reinforcement (PSR), dry heat the thermoplastic tubes with a heat gun or butane torch and adhere to the splint base between wrist and MCP joints, taking care to maintain the central tunnel of the tubes. Note: The use of wet heat will not ensure a secure bond of the tubes to the splint base. 8. To ensure that the LTT will bend to allow wrist flexion, minimize the width and contours of the LTT over the dorsum of the hand. Reinforced palmar strap 1. Apply a piece of self-stick hook VelcroÒ (1 in 3 2 in/2.5 cm 3 5 cm) over the tubes (see Fig. 6d). 2. Cut a piece of 1-in (2.5-cm) wide loop VelcroÒ long enough for a palmar strap that attaches to this hook VelcroÒ. 3. To create the palmar strap reinforcement (PSR), dry heat a piece of LTT (PSR in Figure 1), adhere to the plush side of the palmar strap and mold to the contours of the transverse palmar arch. 4. Optional: cover edges with foam tape as needed for comfort (see Fig. 6f). Finger extension assists 1. Mark the dorsal center of each middle phalanx with a dot of lipstick. 2. Apply the splint, secure with straps, then passively extend the fingers, to carefully and accurately transfer the lipstick mark to the LTT. 3. Punch holes through the LTT at the location of the lipstick marks. To ensure that the cords do not fray with friction going through the holes, reinforce each hole with a metal grommet or a thermoplastic tube (see Fig. 6d). 4. To prevent tearing of the finger slings, even when the holes are reinforced with a metal grommet, consider reinforcing the holes with LTT as follows. Dry heat a small piece of uncoated LTT, adhere it over holes then punch a new hole through the LTT (see Fig. 9). 5. Securely tie an 8-in (20-cm) elastic cord to each finger cuff using a bowline knot. Numerous Web sites demonstrate how to make knots. For example, check out www.animatedknots.com. Thread each cord through a hole in the splint base, then thread two cords through each tube. Another method to ensure that a knot does not become untied is to apply nail polish over a simple knot. 6. Use a 4-in (10-cm) long cord to create a tension adjuster around one cord coming through the tubes, using a girth hitch knot (Figure 2). Tighten the knot. 7. Line finger cuffs with thin self-adhesive padding (e.g., PlastazoteÒ) to prevent migration and stretching of the cuffs and to provide sufficient stiffening to prevent them from collapsing when applying the splint. 8. Apply splint and adjust tension in each elastic finger cord by sliding the tension adjuster proximally or distally. 9. Optional: use different color cords to help distinguish the cord attached to the finger cuff (e.g., white) from the tension adjustor cord (e.g., black). Alternatively, distinguish the cords with different colors of highlighter pens.
JanuaryeMarch 2007
71
Wearing regimen
Splint care
Precautions and patient education
Options
Thumb extension assist (see Fig. 6d) 1. Mold the thermoplastic around the thumb, overlapping the thermoplastic dorsally and ensure a secure bond with no crevices. 2. Determine the appropriate location for a loop VelcroÒ strap to optimally position the thumb in extension/ abduction. 3. Apply hook VelcroÒ to the thermoplastic thumb component and another piece to the forearm base. 4. To ensure that the hook VelcroÒ will not peel off the base, melt about 1/8 in (3.2 mm) of the hooks (using dry heat from a heat gun or butane torch) from the vulnerable edge of each patch of hook VelcroÒ. 5. Attach the loop VelcroÒ strap with sufficient tension to extend/abduct the thumb but loose enough to allow finger opposition. d During functional activities. d For some social situations, a simple wrist splint—custom or prefabricated—might be preferred. d For night, a wrist splint or wrist-hand splint can be worn. d Advise patient how to clean the splint. Extra attention to careful cleansing is needed if the splint is lined. Margareta Persson suggests placing the splint in a lingerie bag and washing in cold water on a gentle cycle in a washing machine. Mrs. M. hand-washed the splint with DoveÒ Daily Hydrating Cleansing Cloths. Allow to air dry. d Patient lacks sensation through radial nerve distribution, thus check carefully for skin irritation before patient leaves the clinic. d Teach patient to look for red marks and instruct patient to return to clinic for adjustments if signs of irritation are observed. d Thumb component can be excluded if palmar abduction is sufficient to allow functional thumb motion. d Modify the design to exclude the forearm base (i.e., convert to hand-based design) when wrist extension does not need assistance (see Fig. 11). d Exclude fabric lining and provide a stockinette sleeve to wear under the splint.
FIGURE 2. Girth hitch knot used to create a tension adjuster on the elastic cord attached to each finger cuff.
REFERENCES
FIGURE 1. Pattern for thermoplastic components of lowprofile dorsal dynamic wristefingerethumb assistiveextension splint. PSR-palmar strap reinforcement. The distal end of the splint is at the distal interphalangeal joint creases. Note the placement of padding adjacent to metacarpal heads and dorsal wrist. 72
JOURNAL OF HAND THERAPY
1. Salter RB. History of rest and motion and the scientific basis for early continuous passive motion. Hand Clin. 1996;12:1–11. 2. Wright TW, Glowczewskie F Jr, Cowin D, Wheeler DL. Radial nerve excursion and strain at the elbow and wrist associated with upper-extremity motion. J Hand Surg [Am]. 2005;30:990–6.