Understanding Stroke-Induced Bilateral Contractures

how can a stroke cause bilateral contracture

A stroke can cause damage to the brain and associated motor pathways, inhibiting purposeful muscle activation and restricting the voluntary movement of the associated limb. This can lead to a condition called spasticity, where muscles contract for long periods or go into spasms, becoming stiff and tight over time. If left untreated, spasticity can result in permanent shortening of the muscles, known as a contracture. This condition affects the ability to perform functional activities and can be painful, negatively impacting one's quality of life. Contractures typically develop in joints and muscle groups like the hand, elbow, hip, knee, and ankle.

Characteristics Values
Definition Contractures are losses in joint range due to changes in the passive mechanical properties of soft tissues spanning joints.
Cause A stroke can damage the way the nerves control muscles, leading to muscles contracting for long periods or going into spasm, known as spasticity or hypertonia.
Affected Body Parts Hands, elbows, hips, knees, and ankles.
Effects Contractures can affect your ability to perform functional activities including walking, transferring between surfaces, and self-care tasks such as dressing or bathing.
Prevention Regular stretching, range of motion exercises, physical exercise, optimal positioning, and electrical stimulation.
Treatment Physiotherapy, injections of botulinum toxin type A, muscle relaxant medication, splinting and casting, and surgery.

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Muscle weakness and loss of motor function

A stroke can cause muscle weakness, also known as hemiparesis, down one side of the body. This can lead to difficulty moving the arms or hands, or affect walking. Around one in four stroke survivors experience muscle weakness.

Muscle weakness can be caused by a decrease in muscle mass, fibre length, and pennation angle, as well as an increase in tendon compliance. These factors reduce the affected muscle's ability to generate force. The result is a shift in the length-tension curve, a downward shift in the torque-angle curve, and a downward shift in the force-velocity curve.

In addition, a stroke can damage the way the nerves control the muscles, leading to muscles contracting for long periods or going into spasm. This is known as spasticity or hypertonia and affects around one in four stroke survivors. Spasticity can develop within a week of a stroke or some time later. If left untreated, it can lead to permanent shortening of the muscles, known as a contracture. This can cause difficulties with movement and performing daily tasks.

To prevent and treat muscle weakness and loss of motor function after a stroke, early intervention is crucial. This includes:

  • Passive range-of-motion (ROM) exercises: Moving the joints through their full range of motion to prevent contractures and maintain flexibility. This can be done by a clinician or caregiver if the person is paralysed.
  • Bracing: Using supportive devices to enable correct positioning and reduce spasticity during specific movements.
  • Splinting: Using a splint to maintain correct positioning and reduce spasticity.
  • Serial casting: Applying a fiberglass cast to hold a body part in position and stretch tight muscles.

In addition to the above interventions, physiotherapy and occupational therapy can help to keep muscles and joints flexible and reduce the possibility of contractures.

In some cases, botulinum toxin type A injections may be used to treat muscle weakness and spasticity. This blocks the action of nerves on the muscle, reducing its ability to contract. It is usually given in combination with rehabilitation, such as physiotherapy, splinting, or casting, to ensure that any range of motion gained is maintained.

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Spasticity

If left untreated, spasticity can lead to permanent shortening of the muscles, known as a contracture. This can cause the joint to become fixed in an abnormal and painful position, with limited movement. Contractures typically occur in the hands, elbows, knees, or ankles.

Treatment

It is important for people with spasticity to stay as active as possible and continue with their exercises, as inactivity can worsen the condition. Physiotherapy and occupational therapy can help improve movement and control and prevent further problems. Physiotherapists can teach stretching exercises to patients with spasticity to avoid contractures and show their family or carers how to help with the exercises. Occupational therapists may provide splints to help maintain a good range of movement in the limbs.

In addition to therapy, there are several medical treatments for spasticity:

  • Botulinum toxin type A: This is injected into the affected muscles to block the action of the nerves, reducing their ability to contract. It is usually combined with physiotherapy and is effective for about three months.
  • Muscle relaxant medication: These can help reduce stiffness and pain and make it easier to move and stretch the affected limbs.
  • Oral medications: These help relax the nerves so they don't send continuous messages to the muscles to contract.

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Electrical stimulation

ES has a developing evidence base and is recommended for use within national guidelines, although this is not consistently applied. Its use is generally considered as an adjunct to standard treatment rather than a stand-alone intervention. Evidence supporting the use of ES for reduction of shoulder subluxation is robust for treatment in the early phase. Evidence supporting its use is less conclusive for improving motor control to aim for improved arm function. While benefits have been shown, they do not always transfer to meaningful improvements in activities or ADLs, and limited studies have investigated benefits with long-term follow-up.

ES can be applied by qualified health professionals, including physiotherapists and occupational therapists who are competent in its use. ES can be provided via single-channel or multi-channel devices. Multichannel systems can be used when targeting multiple muscles to replicate a functional activity such as reaching and grasping, whereas a single-channel device is used for less complex movements such as rectifying shoulder subluxation.

The majority of trials used ES delivered by external electrodes which produced or enhanced contraction of the paretic muscle. ES can be used to strengthen weak muscles, increase the range of motion, reduce spasticity, improve motor control, reduce shoulder subluxation, reduce pain associated with shoulder subluxation and spasticity, improve sensory and proprioceptive awareness, and improve the effects of botulinum toxin for the management of spasticity.

There are several types of ES:

  • Neuromuscular electrical stimulation (NMES)
  • Functional electrical stimulation (FES)
  • Transcutaneous electrical nerve stimulation (TENS)

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Multi-modal therapy

A multi-modal therapy program for contractures combines passive stretch with treatments that address the contributors. This approach can produce lasting benefits for the correction of contractures. A recommended multi-modal program comprises serial casting and botulinum toxin, followed by splinting and motor training. People with lesser residual physical impairments or better prospects for functional improvements are more likely to respond well to the program.

The following is an example of a multi-modal therapy program for upper extremity improvements in chronic stroke patients:

  • Coupled bilateral training with a load on the unimpaired hand
  • Coupled bilateral training with no load on the unimpaired hand
  • Control (no stimulation assistance or load)

The study found that the coupled bilateral groups moved a higher number of blocks and demonstrated more regularity in the sustained contraction task. Faster motor reaction times across test sessions for the coupled bilateral load group provided additional evidence for improved motor capabilities.

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Passive stretch

The effectiveness of passive stretching in reducing spasticity and improving range of motion is still uncertain. Some studies have shown that passive stretching can improve spasticity and motor functions, while others have found no significant results. The duration of the stretching, the number of repetitions, and the type of stretching used may influence the effectiveness of the treatment.

To optimise the benefits of passive stretching, it is important to perform it periodically and for a prolonged period. Additionally, combining passive stretching with other treatments that address the underlying causes of contractures, such as spasticity and muscle weakness, may be more effective than sole interventions.

Overall, passive stretching is a valuable tool in the management of contractures after a stroke, but it should be individualised and adapted to each patient's needs by a therapist.

Frequently asked questions

A stroke occurs when the brain's blood supply is interrupted or reduced, preventing brain tissue from receiving oxygen and nutrients. This can cause brain damage and a range of physical and mental health issues.

A stroke can cause nerve damage that affects muscle control, resulting in spasticity or hypertonia. Spasticity leads to increased muscle tone and tightness, causing difficulties with movement. If left untreated, spasticity can lead to permanent muscle shortening, known as contractures, which restrict joint movement.

To prevent contractures, it is important to maintain muscle flexibility and range of motion. This can be achieved through regular stretching, range-of-motion exercises, physical exercise, optimal positioning, and electrical stimulation. Treatment options for existing contractures include splinting, casting, botulinum toxin injections, and in severe cases, surgery.

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