Upper Limb Orthotics/Orthotic Intervention for Children with Cerebral Palsy


 * /Orthotic Intevention for Children with Cerebral Palsy/

Case study
The patient is a 7 year old girl with spastic hemiplegia cerebral palsy (CP) affecting her left side. The patient is ambulatory with the assistance of an ankle foot orthosis (AFO). The patient’s left wrist is in moderate flexion (45°), ulnar deviation and thumb adduction. The pattern of deformity makes fine manipulation difficult due to the dysfunction of the thumb, however good grasp and pinch and release are seen (Wilton, 2003). Examination shows full passive range of motion (ROM) at the wrist and fingers. The thumb-index web space shows some reduced ROM and possible contracture. A useful tool for the clinician is a Modified Ashworth (MAS) and Modified Tardieu scale (MTS) which can assess and document changes to level of spasticity with treatment (Bohannon, & Smith, 1987; Tardieu, Shentoub and Delarue, 1954). The tool uses a five point scale where 0 is no increase in tone and 4 is a rigid joint. The patient’s current level of spasticity in the wrist is graded as a 1 and abduction of the thumb is graded as 2. The patient has started grade 3 at the local primary school. The goals for treatment the patient has outlined include being able to dress herself, typing on the computer to complete school assignments, and playing ball games with her friends during recess and lunch time.

Anatomy and Pathology
The area affected and being treated is primarily the wrist hand and thumb. Mild spasticity of the flexor carpi ulnaris (FCU) is seen in the patient resulting in flexion and adduction (ulnar deviation) at the wrist (Moore, & Dalley, 2006). Adduction at the carpometacarpal joint (CMC) is a result of contraction and contracture of the adductor pollicis (AP) and first dorsal interosseous (DI) muscles (Wilton, 2003).

Pathology and upper limb
Cerebral palsy is a neurodevelopmental disorder caused by non-progressive lesions in the immature brain in utero, during or shortly after birth (Gordon, Charles, & Wolf, 2005; Chin, Duncan, Johnstone, & Graham, 2005). Hypertonicity, contractures and spasticity of the upper limb are often observed (Lannin, Novak, & Cusick, 2007; Burtner, Poole, Torres, Medora, Abeyta, Keene, & Qualls, 2008). The stereotypical patterns of movement in the upper limb are internal rotation of the shoulder, flexion of the elbow and pronation of the forearm, flexion and ulnar deviation at the wrist and adduction of the thumb (Burtner et al., 2008; Yasukawa, Lulinski, Thornton, & Jaudes, 2008). The prevalence of cerebral palsy is approximately 2.0-2.5 per 1000 live births in Australia (Flett, 2003), of these births hemiplegia accounts for approximately 25% of new cases worldwide (Gordon, Charles, & Wolf, 2005), which makes it the most common physical disability affecting children in developed countries (Stanley, Blair, & Alberman, 2000).

Orthotic treatment options
Orthoses, splints and braces are interchangeable terms used to describe a supportive or corrective device. Orthoses are commonly used to improve the position, range and quality of movement, and the function of a person’s arm or hand (Teplicky, Law, & Russell, 2002). The orthotic options the clinician can choose from are vast, and considerations must be made about materials, hand and wrist position, time worn and goals of the client. The materials commonly used for treatment of cerebral palsy include low-temperature thermoplastics, plaster of Paris or fibreglass casts, neoprene splints and Lycra splints. The overall design of the device and force systems at work will reflect the functional aims of the client and clinician.

Comparison of orthotic treatment options
Splinting and casting the upper extremity of children with cerebral palsy is common practice, however care and consideration must be taken when deciding when orthotic intervention is necessary and what type of orthosis is the most appropriate for the client.

Static splints are designed to maintain one or multiple joints in a fixed, rigid position. The goal of the splint may be to stabilise the joint for improved transfer of muscular forces, or to manipulate the joint to preserve the architecture of the hand and prevent any further deformity (Coppard, & Lohman, 2001; Wilton, 2003; Hsu, Michael, & Fisk, 2008). Static splints have been shown to improve function of the hand (Teplicky, & Russell, 2002), however literature suggests that changes may be very small, and that these positive changes are often short lived, normally within 2 to 3 months after removal of splint (Jackman, Novak, & Lannin, 2014). It is also suggested that prolonged use of static splints that immobilise wrists may decrease muscle activation and result in disuse muscle atrophy of the wrist musculature (Burtner et al., 2008; Bulthaup, Cipriani, & Thomas, 1999).

Dynamic splints use a combination of immobilisation and resisted movement at certain joints to prevent contractures. Dynamic splints have moving parts that allow a greater range of movement against resistance. It has been proposed that the use of dynamic splints may prevent contractures while allowing opposing antagonist muscle force to counter the force of spastic muscle (Burtner et al., 2008). The dynamic splints often use low temperature thermoplastics with springs and wires to provide resistance, other designs may use materials such as neoprene and Lycra to provide support and resistance. Neoprene and Lycra splints use a circumferential design with force applied to joints via metal or plastic inserts to position. These splints are useful, however neoprene and Lycra have a high level of elasticity; this makes splinting severe spasticity and contractures difficult (Wilton, 2003).

Casting the upper extremity to improve function is common practice among clinicians. Serial casting involves periodic casting and recasting over the treatment period. The casts are designed to progressively increase the stretch on the muscle group (Brouwer, Wheeldon, Stradiotto-Parker, & Allum, 1998). Inhibitive casting involves the use of special techniques designed to decrease the effect of reflexes and, in turn, decrease tone (Stanger, 1997). Casting has been shown to improve ROM and decrease tone in children with cerebral palsy (Copley, Watson-Will, & Dent, 1996).

The orthosis being prescribed to the patient will aim to maintain the extensibility of tissues around the wrist by holding the wrist in slight extension to ensure the flexors do not undergo contracture. The orthosis will aim to move the adducted thumb into a more functional position and reduce contracture. The clinician will be challenged during casting due to the spasticity of the adductor pollicis muscle and contracture of the skin in the web space; however an abducted position is crucial to maintain a functional thumb. The material best suited to this application is a low temperature thermoplastic due to the increased rigidity compared to neoprene or Lycra. The static splint will only be worn during non-functional times i.e. during sleep and times of inactivity, this will allow for activities that may incorporate weightbearing to provide stretch to the FCU (Wilton, 2003). A dynamic splint may be worn during times where dexterity, pinch and grasp are important such as during school and performing activities of daily living (ADLs).

Search Strategy
The databases of CINHAL, MEDLINE, Cochrane Library and Google Scholar were used. Multiple searches were conducted with search terms such as “Cerebral palsy”, “Spasticity”, “Hypertonicity”, “Contracture”, “Upper limb”, “Orthosis”, “Splint” and “Brace”. Varying combinations of these search terms were used to try to produce as many relevant results as possible. Boolean operators were used to refine the search and Wildcards were used to ensure “orthosis” and “orthoses” were both included in a search by the inclusion of ?, “orthos?s”. Once up to date, relevant articles were found it was possible to ‘reference trawl’ to find more articles.

Conclusion
In conclusion, the patient with spastic hemiplegia cerebral palsy affecting the wrist and hand may benefit from an orthosis worn during the night to reduce severity of contracture. The orthosis will be made out of low temperature thermoplastic and aim to correct and reduce deformities by holding the wrist in slight extension and thumb in abduction to minimise contracture.

Functional Aims and Goals
The low temperature thermoplastic orthosis will aim to move the adducted thumb into a more functional position to try and correct the deformity as well as prevent any progression of deformity. The orthosis will realign the wrist, fingers and thumb to oppose the spastic muscles to provide stretch and reduce likelihood of contractures. The static splint will mainly be worn during non-functional times i.e. during sleep and inactivity, a dynamic splint may be worn during activity to allow resisted movement to stretch and strengthen involved muscles. The material best suited for the static and shell component of the dynamic splint is a low temperature thermoplastic. Low temperature thermoplastic will provide strength and resist the forces of the spastic muscles. The low temperature thermoplastic is easily able to be remoulded to provide more stretch to the muscles as the treatment progresses.

The POP orthosis aims to use serial casting to improve the position of the wrist, fingers and thumb by casting and recasting periodically over the treatment period. The casts are designed to progressively increase the stretch on the muscle group (Brouwer, Wheeldon, Stradiotto-Parker, & Allum, 1998). The downside to serial casting is the possibility of muscle atrophy and difficulty bathing and performing other ADL’s. A plaster backslab may be applied and suspended with a crepe bandage, this would allow for easy donning and doffing to perform basic hygiene and ADL’s however the increased weight of a plaster backslab over a low temperature thermoplastic makes it a less appropriate choice of device.

An orthosis fabricated from a plaster cast with a high temperature thermoplastic is another option for clinicians. The aims of this orthosis will be similar to that of the low temperature thermoplastic however this material may be used to make a more definitive orthosis that has increased strength and support to resist highly spastic muscles or larger muscle groups. The high temperature thermoplastic would have to be draped over a plaster mould instead of cast on the patient’s limb. The manufacturing process is more time consuming and will delay the initial wear time for the patient compared to using low temperature thermoplastic. The advantage of using a high temperature thermoplastic for our client is the added strength, the client is a primary school student that wishes to participate in “ball games with her friends during recess and lunch time” a stringer device would be able to better handle the rough and tumble lifestyle of a primary school student.

Design
The low temperature thermoplastic orthosis will aim to extend the currently flexed wrist, correct the severe ulnar deviation and move the adducted thumb into a more functional position to try and correct the deformity as well as prevent any progression of deformity. The orthosis will realign the wrist, fingers and thumb using three-point force systems shown if figures 1 and 2 to oppose the spastic muscles to provide stretch and reduce likelihood of contractures.

The forces at play in figure 1 are resisting the spastic flexor muscles to move the wrist into a more functional extended position. The orthosis is designed to use the longest lever arm possible to maximise the force while minimising the pressure on the patient’s soft tissue. Figure 2 shows the force systems to resist ulnar deviation and thumb adduction.

Manufacturing process
The process form manufacturing the low temperature thermoplastic orthosis:

1.	Draw and measure design

The hand of the patient is outlined on a piece of ‘chux’ with a permanent marker. Relevant anatomical landmarks are marked and the orthosis template is drawn over the hand outline.

5.	Position patient

While the plastic is back in the warm water to reheat, the patient can be positioned appropriately, this is usually sitting in a chair with their elbow resting on the arm rest or table and their elbow flexed (as if they’re about to arm wrestle).

6.	Mould thermoplastic

Take the soft thermoplastic template out of the water and dry off with a towel, drape the thermoplastic over the patient’s wrist, hand and thumb while in the correct position. Allow the thermoplastic to cool and remove from patient.

7.	Adjust trimlines

Place the orthosis back on the patient and assess the trimlines, care should be taken around bony landmarks and distal and proximal trimlines. The proximal trimline of a WHO should allow full elbow flexion. To adjust the trimlines the edges involved may by carefully heating (make sure the integrity of the design is not altered) the orthosis in the water and cutting the soft edges. Straps can be measured and heat gunned in place as well as Velcro hooks. 8.	Adhere straps and Velcro

Straps can are to be measured on the patient and using a heat gun adhered to the orthosis. Velcro hooks are to be added to the orthosis using the heat gun in the same way.

9.	Assess fit

Assess the fit of the orthosis on the patient. Make any adjustments to strap length or placement, if the straps are uncomfortable and digging into the patient a piece of EVA foam or pelite can be used as adding on the strap.

Critique of fit
The patient is a 7 year old girl with spastic hemiplegia cerebral palsy (CP) affecting her left side. The patient is ambulatory with the assistance of an ankle foot orthosis (AFO). During the assessment the patient complains that her thumb sometimes “digs” into her palm and causes pain. During the objective assessment it can be seen that the patient’s left wrist is in moderate flexion (45°), ulnar deviation and thumb adduction. The dysfunction of the thumb is causing some pain I the palm area and makes fine manipulation difficult, however good grasp and pinch and release are seen (Wilton, 2003). Examination shows full passive range of motion (ROM) at the wrist and fingers. The thumb-index web space shows some reduced ROM and possible contracture.

The orthotic goals outlined by the patient include being able to dress herself, typing on the computer to complete school assignments, and playing ball games with her friends during recess and lunch time. The resting WHO aims to hold the wrist in extension, this will stretch the flexors and reduce likelihood of contraction. The thumb gutter aims to move the thumb out of the palm of the hand to increase functionality and decrease pain and possible skin breakdown of the palmar surface.

The device is made out of low temperature thermoplastic. Initially it was thought that the thickness of the plastic used would be strong enough to resist the spastic flexors at the wrist and fingers. During the initial fitting the plastic was too flexible and provided very little support. Another design was used with a more circumferential wrist component however this was also very flexible so a strip of plastic was cut and moulded onto the palmar surface of the orthosis to add extra support. In hindsight a thicker piece of low temperature thermoplastic would have been used or alternatively a high temperature thermoplastic could have been moulded onto a plaster cast of the patient’s wrist and hand.

The device fits the patient well and conforms nicely to the anatomy of the wrist and hand. The straps are positioned as far distal and proximal as possible to maintain the longest lever arm possible and reduce the magnitude of forces applied to the soft tissue. The distal trimlines on the orthosis may be slightly too long, as seen in figure 7 however a longer distal trimline is preferred to a short trimline because the tips of the fingers may overhang the orthosis and cut into the volar surface of the finger and cause skin breakdown. The added length at the distal end may also allow for some growth considering the patient is 9 years old. It would be advised that a new orthosis would be constructed after growth spurts to maintain a close fit.

Outcome measures
The outcome measures chosen to assess the effectiveness of the intervention are wrist and hand range of motion (ROM). The clinician will assess and document the patients ROM using a goniometer. This provides an objective baseline figure to compare ROM during treatment to assess if the intervention, a resting wrist and hand orthosis, is preventing progression of, or correcting the deformity. The Upper Extremity Functional Index 20 is the other outcome measure chosen to assess the effectiveness of the intervention. This test was chosen over other outcome measures due to its specificity to the patient’s goals and lifestyle and the simplicity of the test. Other tests such as the Disabilities of the Arm, Shoulder and Hand (DASH) appear far too complicated for a 9 year old girl and having her mother help her answer the questionnaire might bias the results. The Croft Disability Questionnaire is specific to shoulder function and is therefore an unsuitable outcome measure for wrist and hand function and the Human Activity Profile asks questions that aren’t relevant for a 9 year old school girl. The length of the questionnaire (94 questions) is also a deterrent when treating a young patient.

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