Name: Stephanie Caisley
Title: Problem based learning
Course code:
Student number: 201411954
Word count:2482
This certifies this is my own work
Date:28th February 2016
Problem based learning with multiple sclerosis.
Effects of the condition and other affecting factors
The patient presents with Multiple Sclerosis (MS) and is within the common age for the disease, 15 to 50ᵒ(Schapiro,ᵒ1998). This is caused by demyelination of the brain or cervical or thoracic level spinal cordᵒ(Perryᵒetᵒal., 2010). Myelin is associated with nerve impulse conduction, damage to which is associated with the loss of smooth, rapid and coordinated muscle movements with little conscious effortᵒ(Schapiro). The area where demyelination occurs forms hardened sclerotic or scarred tissue and results in the disability and potential cognitive problemsᵒ(mssociety.org.uk, 2016). The symptoms of MS vary between patients dependant on lesion location. When demyelination occurs in nerves regulating muscle tone or movement spastic paralysis can result, contributing to progressive muscle weakness, impaired selective control, spasticity and the emergence of primitive motor patterns, all of which the patient is beginning to demonstrate with her lower limbsᵒ(Perryᵒetᵒal.). The disease is characterised by recurrent waves of exacerbation followed by improvement or stability. The type of MS dictates the speed of the pathology’s disabling effectsᵒ(Waksman). Malignant MS has a progressive downhill course, which can lead to fatal respiratory failure, whereas benign MS has fewer attacks with little or no resulting disability. The specific type of MS is not stated here, though this will influence the progression of the disease and ultimately the rate of orthotic change.
Muscle weakness with progression is a primary finding of this type of pathology with further weakening of other muscle groups including postural musclesᵒ(Perryᵒetᵒal.). This patient’s dorsiflexor and evertor weakness corroborates this, and could impact on balance. No muscles strengths have been provided; the Oxford Muscle Test Scale values quantifying the level of weakness would be beneficialᵒ(Sapega). These test voluntary isometric muscle assessing both the contractile tissue as well as the supplying nerves. MS patients may have sufficient muscle contractile fibres, but not enough nerve impulses capable of stimulating it.
For swing phase in gait, a minimum muscle strength of three is necessary, allowing for complete range of motion under gravity. During stance as the additional force of body weight needs supporting, a muscle strength of at least four is necessary to facilitate normal gait. Without knowing the degree of muscle strength loss, nor the condition of the proximal muscles and orthotic prescription is difficult because the degree of functional loss, and therefore the corrective forces required cannot be accurately determined.
Impairments in selective control, distinguishable from muscle weakness or flaccid paralysis because reflexes remain intact, is caused by the gradual loss of timing and intensity of muscle actionsᵒ(Perryᵒetᵒal.). Initiating unique muscle combinations is difficult with primitive motor control of the whole limb becoming more apparentᵒ(Perryᵒetᵒal.). Furthermore there is an inability to moderate muscle action intensity, a presumed influencing factor in the patient’s fatigue and stiff awkward gait. With this, the ankle will end up in plantarflexion, which is mentioned in the patients information, and could be partially related to the pretibial and knee extensor musculature not being able to provide enough activity during loading responseᵒ(Perryᵒetᵒal.).
Primitive motor control, an alternative form of voluntary muscle control, allows the patient to take a step via the mass flexion pattern, where the hip and knee are flexed and the ankle is dorsiflexed with inversion as much as the patient can permitᵒ(O'Sullivanᵒ&ᵒSchmitz, 2010). At initial and mid-swing the foot is dorsiflexed due to the mass flexion pattern. From terminal swing to achieve stance phase stability the mass extension pattern is observed, where the knee and hip are extended and the foot is plantarflexed and everted, again to within the patients limitsᵒ(Perryᵒetᵒal.). Due to this synergy the gastrocnemius and soleus are activated, which could be a cause for the stiff awkward gait, because of an inability to mix flexion and extension, causing the loss of smooth transition between stance and swing phase.
Mass extension or flexion pattern could cause tripping, which would be expected at later mid-stance to terminal swingᵒ(O'Sullivanᵒ&ᵒSchmitz). Spastic primitive extensor response fits more conclusively with the pathology in this case and distinguishes the ankle motion from a plantarflexion contracture ᵒ(Perryᵒetᵒal.).
Spasticity present in the plantarflexors, such as soleus and gastrocnemius, could result in the patient’s plantarflexed foot, limiting second rocker, preventing third rocker and producing an uneven step length or the absence of terminal stance during gaitᵒ(Perryᵒetᵒal.). The main functional difficulty would be loss of progression, which is characterised by premature heel off, hyperextension of the knee and forward trunk leanᵒ(Perryᵒetᵒal.). Difficulty obtaining upright posture could lead to a decrease in balance, due to the lack of tibial progression.
The patient may trip and toe drag due to the loss or weakening of flexion synergy muscles. This fits with the weakened dorsiflexor, though the hip and knee flexor strengths are not reportedᵒ(Perry etᵒal.). To provide toe clearance in swing of a plantarflexed foot, there is excessive knee and hip flexion, which should be observable. If this is not apparent, there may be circumduction, contralateral vaulting and lateral trunk lean. All of these increase energy demands, contributing to fatigue. The presumed foot drop may cause the forefoot to make contact with the ground prior to the heel, detrimentally affecting balance.
Spasticity is energy intensive; nerve damage and the conscious effort to fire muscles are contributing factors to fatigue. This is more apparent in the quick muscle test that can result in a catch or clonus, it is also present during a slow stretch, but can be misdiagnosed as a contracture or range of motion limitation, as opposing muscle action is continuous. The fatigue the patient suffers is not described in detail, but there are various forms. Short-circuiting fatigue is a weakened limb that will further weaken when fatigued and will only recover when rested. However a level of activity is needed to prevent muscles deconditioning, which in turn causes a different type of fatigueᵒ(Schapiro). Lassitude, the most common type of fatigue in MS patients, is a sleepiness that can come on abruptly and is thought to be biochemical in origin.
The loss of proprioceptive function may contribute to the loss of balance and awkward gait. Damage to the vestibular or balance mechanism of the brain can fluctuate in severity spontaneously due to the MSᵒ(BSRM, 1994).
The patient mentions no pain, which is not surprising as 80% of MS sufferers consider it to be a painless disease, although there may be pain associated with spasms linked to spasticityᵒ(BSRM; Schapiro).
Multidisciplinary team approach
It is important to consider not just the physical effects but also the psychological effects associated with engaging a multidisciplinary team, which can be vast as different disciplines are required such as dietitians, speech therapists, biofeedback technicians and therapeutic recreation specialistsᵒ(Burksᵒ&ᵒJohnson, 2000; Maloneyᵒetᵒal., 1985). Some will have a more direct effect on the orthotic implication and progression of the patient such as physiotherapists, neurologists, physiatrists, physicians, rehabilitation nurses and occupational therapists. Other members of the team such as counsellors and social workers may encourage compliance with the orthoses.
Vision may be affected due to demyelination, an influencing factor in balance, gait and ability to properly don the deviceᵒ(Schapiro). The optometrist may be the first person to suspect MS, as isolated optic neuritis is often the primary symptom of the pathology, with 30-70% of patients with this pathology going on to develop MSᵒ(Burksᵒ&ᵒJohnson).
Some muscle weakness can be strengthened by weight lifting with progressive restrictive exercises. Weakness caused by electrical impulse transmitting problems, due to demyelination can cause muscle dystrophy, which will be detrimentally affected by such exercises if the muscles pass the point of fatigueᵒ(Schapiro; Maloneᵒetᵒal.). However a muscle that is not stimulated will atrophy, a specialist MS physiotherapist can guide the patient with repetitive strength exercise, thereby strengthening weak areas so complimenting the advantages given by the orthoses.
The spasticity maybe used to maintain posture so it is important to normalise the tone without compromising support. This can be controlled via medication, nerve or motor point blocks and limb positioningᵒ(Schapiro; BSRM). Medication needs to be used with care as it can also negatively or positively affect balance. This can also be aided with coordination and balance exercises such as patterning with the assistance of occupational and physiotherapists, orthosis to maintain position and walking aids such as a canes, forearm crutches, rollators and walkers (Schapiro, 1991).
Any depression should be managed as it is important to increase and conserve energy. To ensure she can continue with her PhD, the occupational therapist may provide assistance in prioritizing activities, allowing for rest periods in between.
Prescription
It is important to consider cognitive problems associated with MS and ensure comprehension. Restricted patient information and the inability to observe ambulation makes the selection of the ankle foot orthosis, AFO, more challenging.
The prescription of an AFO is indicated due to the weak dorsiflexor and evertor, limited dorsiflexion and spastic plantarflexors. The weakened dorsiflexor and the spastic plantarflexors cause a particular imbalance, as they both contribute to the deformity in the plantarflex orientation. Due to the weak evertors, there is a higher likelihood of a supinated foot, though the degree of this is unknown as the extent of weakness is unidentified. Therapeutic stretching of the plantarflexors as a result of wearing an AFO would be an additional benefit.
The amount of mediolateral stability needed to accommodate the sub-talar joint and mid-tarsal joint deformity will dictate whether a solid ankle AFO or articulated AFO would be prescribed. In either case a custom AFO prescription would correct a more significant deformity than a prefabricated one, for example the incorporation of a wedge to resolve the dorsiflexion limitation and the fact that effort is required to correct the subtalar joint and midtarsal joint.
A solid ankle AFO would be prescribed if more mediolateral support is indicated on either limb as these prevent or restrict plantarflexion and dorsiflexion. In the brief, it states there is a bilateral correctable sub-talar and mid-tarsal joint, presumed to be a supination deformity. The degree of the deformity is not stated, however in combination with the weak evertor muscles this can be presumed to be present. Further assessment would be needed to ascertain whether the sub-talar joint or mid-foot collapses during dorsiflexion, and if there is any proximal muscle weaknesses.
A posterior leaf spring AFO is easier to accommodate in the patients footwear but it is not rigid enough to cope with the spastic plantarflexors or provide any mediolateral correction forces for the sub-talar and midtarsal joint, and so cannot be prescribed.
If moderate mediolateral support is required articulated joints could be prescribed. An articulated ankle joint limits plantarflexion but still allows for dorsiflexion, giving easier stand to sit motion, as well as gastrocnemius stretch. The benefit to the patient is dependent on the sensitivity of the spasticity in the plantarflexors, as it can cause clonusᵒ(Burks &ᵒJohnson).
If an articulated joint is chosen then a plantarflexion stop should be incorporated to prevent excessive plantarflexion, this permits free dorsiflexion, but prevents the foot part of the AFO slipping underneath the shin portion which could otherwise cause pain and skin breakdownᵒ(SRT). With the stop in place there is still some medialateral, talar and subtalar joint stabilisationᵒ(Bedardᵒetᵒal., 2013).
There are different types of articulated ankle joint with varying levels of suitability. The free ankle is not suitable due to the weak dorsiflexor, hypertonus and inability to control significant evertor weakness leading to sagittal plane instability. Neither the dynamic ankle foot orthoses, DAFO, or supra-malleolar orthosis, SMOs, are capable of providing enough rigid support against the high toneᵒ(Drake, 2010). A dorsiflexion assist AFO could benefit as it assists the patient to dorsiflex the foot and gain the most out of the limited range of motion and weakened dorsiflexor. However this can be excluded due to the spastic plantarflexor musculatureᵒ(Fillauer.com, 2016).
A variable assist AFO can provide dorsiflexion assist, and spasticity is not a contraindication for this type of joint. The assistance or blocking that the device can give can be altered if and when the patient’s symptoms worsenᵒ(Bedardᵒetᵒal.). As the patient presents at the moment this type of joint could be fitted, as long as there is no oedema and the mediolateral instability is not excessive. Even though the right side of the lower limb appears to be more severely affected, displaying more limited dorsiflexion, higher tone and weakness, this joint could be prescribed for both feet as the left side also appears to be affected.
After further examination, a combination of solid and articulated AFO may be indicated dependant on the degree of mediolateral stability required for each limb.
Whichever AFO is prescribed, a full foot plate is indicated, providing neurodevelopmental or tone reducing properties as well as aiding correct foot alignment whilst placing the AFO and foot into the shoeᵒ(Bedardᵒetᵒal.).
The full foot plate still allows for stabilisation through total contact proximal to the metatarsal heads. There is no mention of loss of sensation, though this is a common pathology for patients with MS; the full footplate would allow for more protection of the plantar surface of the foot, if this became apparent.
The patient cannot biologically achieve significant dorsiflexion to allow for smoother and apparent second and third rocker. This could cause the stiff and awkward gait that has been reported. The addition of a wedge to externally create this tibial inclination may assist in a smoother, more energy efficient gait.
Prescription suggestions are based on the information provided and assumptions made, further examination of the patient may alter these parameters and orthotic prescription. The effect the orthosis has on the patient depends on their desire to wear it, understanding of the benefit it can provide, in particular to enable her to continue with her PhD, which was a concern expressed.
Cosmetic application will encourage the patient to wear the device. Co-polymer gives greater variety of colours and use of transfers, however the material does not have the stiffness required to correct the deformitiesᵒ(Hsuᵒetᵒal., 2008). Homopolymer material is only available in a translucent white colour, but provides the rigidity required to hold the foot against the plantarflexor spasticity, creating a less bulky device that is thinner, and lighter. This material has good impact strength, but a nick free surface is fundamental to avoid cracking.
Patient footwear must be considered when fitting the device; it must fit inside and accommodate heel heightᵒ(Hsuᵒetᵒal.). The same heel height must be maintained in subsequent shoes as fluctuations will affect, among other things, tibial progression and the stability and action of knee and hip.
Knee and hip pathology have not been highlighted and therefore discounted. A different prescription would be needed if these were present.
Canes may improve balance and are fitted on the contralateral side to the weakness. This assumes there is adequate upper body function to use these. Upper body ability also needs to be taken into consideration when prescribing the orthosesᵒ(Schapiro).
The patient’s gait needs to be assessed pre and post fitting to ensure the prescription is correct, but also to ensure the gait exhibited is energy efficient and not contributing to the fatigue.
References
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