General
- UMN syndrome includes
- Positive phenomenon
- Spasticity
- An involuntary, velocity dependent increase in muscle tone leading to increased resistance to movement.
- It is both amplitude and velocity dependent and is therefore best assessed using rapid movements of the relevant joint to effect abrupt stretching of the muscle group involved.
- When a threshold velocity, angle, or amplitude is reached, a sudden increase in tone can be detected as a characteristic “catch.”
- Due to damage to the corticoreticulospinal (pyramidal) tracts → loss of descending GABA inhibition of antagonistic muscle groups resulting in hypertonia
- Other features
- Hyperreflexia; involuntary muscle contractions (spasms) which cause movement and are often painful; pain or discomfort in the muscle; adoption or maintenance of a particular posture, especially on effort; clumsiness, or reduction of fine motor control; and reduced voluntary muscle strength.
- Generally patients do not complain about spasticity;
- In the short term, they are more likely to be aware of stiffness, deformity and limitations in functional abilities.
- In the long term, the patients will have a mixture of spasticity and muscle shortening or contracture.
- 2 types of deformities,
- Dynamic caused by spasticity
- Fixed contracture
- To differentiate deformity that remains even under local blocks or anesthesia.
- Spasticity should not be treated just because it is present;
- Indication for treatment
- Spasticity should only be treated when excess muscular tone leads to further functional losses, impairs locomotion, or induces deformities, or chronic pain.
- Some spasticity is useful in paraplegic patients (transferring bed to chair)
- Need to use intrathecal baclofen trial is to assess whether this would be lost (not favoring pump implantation).
- Clonus
- Rigidity
- Dysfunction of extrapyramidal pathways, most commonly the basal ganglia, but also as a result of lesions of the mesencephalon and spinal cord.
- Remains constant throughout the range of movement of the joint.
- It is independent of velocity and should even be detectable with very slow movements.
- Given that rigidity frequently arises in diseases of the basal ganglia, a tremor can coexist, giving rise to an interrupted “cogwheeling” effect.
- Negative phenomenon (weakness, incoordination, loss of dexterity).
- Comparison
Features | Spasticity | Rigidity |
Tone | Inc. Tone | Inc. tone |
Pathology | Corticospinal tract | Basal ganglia |
Example | Cerebral palsy/spinal cord pathology (spastic catch) | Parkinsons (cogwheel or lead pipe rigidity) |
Velocity dependence | Yes | No |
Affects antagonistic muscle | Asymmetrically | Symmetrically (present in flexors and extensor muscle groups equally, giving rise to a uniform quality in all directions often described as “lead pipe” rigidity.) |
- DO not use traditional descriptions of spasticity (ashemiplegia, diplegia, and quadriplegia to describe the distribution of the spasticity and the limbs involved) as
- They falsely suggest that the other limbs are unaffected, when they actually may be mildly affected. It is therefore preferred to state the mainly affected limbs (e.g. ‘spasticity mainly affecting the legs’ rather than ‘diplegia’).
- Depending upon the cause of the UMNL, the effects of spasticity may be seen in the upper or lower limbs.
Pathophysiological basis of spasticity
- Incompletely understood
- Arise mainly from injury to the
- Reticulospinal tracts
- Corticospinal/pyramidal tracts and the spinal interneurons.
- The injury leads to a reduction in the inhibitory input to the spinal motor circuits → a consequent exaggeration of the reflex arc.
- Neurophysiology testing
- Increase in motor neurone excitability in the form of Enhanced H- M ratios and F- wave amplitudes
- Within the spinal cord, changes are seen in the excitability of the
- Motor neurones
- Interneurons
- Reflex arc pathways
- In the healthy subject,
- The 1a inhibitory interneurons mediate the reflex arc, receiving descending input from the descending corticospinal pathways as part of this action.
- Due to
- A upper motor neurone lesions (UMNL) → lead to loss or diminution of descending inhibitory influence on the alpha and gamma motor neurones.
- Affected muscles
- Shows
- Shortening and contracture commonly develop over time,
- Muscle spindle sensitivity is usually unaltered.
- Progression
- After acute UMNL → muscle tone is usually low with a flaccid paresis initially → eventually progressing to spasticity.
Aetiology
Cranial origin
- Stroke
- Demyelinating disease
- Cerebral palsy
- Commonest cause of paediatric spasticity
- Incidence of 1 in 500 live births.
- Nonprogressive condition
- Clinical manifestations (variable)
- Spasticity
- Dystonia
- Dyskinesia
- Ataxia.
- While the brain lesion is static, the effects on the musculoskeletal system are often progressive
- Because the muscles grow more slowly than the adjacent bones and also because of an imbalance of forces across the joints.
- These have deleterious effects on the shape of the developing bones and joints.
Spinal origin (Since spasticity arises from an UMNL, it would not be expected to result from a spinal injury below the conus medullaris)
- Cervical spondylitic myelopathy,
- Traumatic spinal cord injury,
- Demyelination
- Multiple sclerosis
- Commonest cause of in adults spasticity
- Immune-mediated Progressive degenerative condition with a variety of courses including relapsing- remitting and gradually/ rapidly progressive.
- Numbers
- It occurs principally in people of a Northern- European origin
- Peak onset around age 30
- A female: male ratio of up to 3:1.
- UK
- Incidence 9.64 per 100 000 population
- Prevalence in England and Wales of 100– 140 per 100 000 population, increasing to 170 in Northern Ireland, 190 in Scotland, 295 in Shetland, and 402 in Orkney.
- Tumor compression,
- Spinal vascular malformations,
- Nutritional myelopathies,
- Tropical/hereditary spastic paraparesis).
- Syringomyelia
Investigation, assessment, and diagnosis of spasticity
Initial assessment
- Detailed history and examination
- Baseline blood tests
- Including FBC/UE)
- Blood/ urine cultures to look for infection.
- Family history is particularly important for children when considering neurodegenerative conditions.
- Specialist investigations such as
- CSF analysis
- MRI scanning
- EMG/ EEG
If sudden exacerbation of their spasticity,
- Assess through
- A detailed history and examination
- Blood tests
- Urine cultures
- Common causes of deterioration
- Infection (especially urine or ear),
- Medication changes
- Pain,
- Pressure sores
- Constipation,
- Occult fracture,
- Foot/ orthotic problems,
- DVT,
- Stress,
- Fatigue,
- Cold weather.
MDT discussion
- Evaluation of which muscles are overactive
- How the spasticity affects the patient throughout their daily life including self- care, mobility, sleep, and employment.
Scoring systems
- Developed to document the extent of spasticity and functional limitation.
- For Extent of spasticity
- Modified Ashworth Scale
- Most commonly used tool
- Use for one single joint PassiveROM (Video)
- When assessing for spasticity in a particular muscle, begin in a position in which that muscle is maximally shortened. (eg From a flexed elbow to test for biceps spasticity)
- Over 1 second (or faster), manually stretch that muscle by moving the joint through the opposite movement.
- E.g., to assess bicep brachii spasticity, begin in maximal elbow flexion, and rapidly move the elbow through EXT passively.
- Clinical use
- Generally patients with an Ashworth score of 3 are candidates for intrathecal baclofen,
- Although those with less severe spasticity may also benefit depending on the clinical context.
- During ITB test dose (25-50 μg in children) for spasticity an improvement of one point or greater is considered positive.
Modified Ashworth scale | Description | Tone |
0 | Moves freely at any velocity | Normal |
1 | Catch and release/minimal resistance at the end of ROM | Slight increase |
1+ | Catch and release/minimal resistance <50% of ROM | Slight increase |
2 | Resistance present throughout the ROM Joint can be easily moved still | Increased |
3 | Very difficult passive movement | Marked increased |
4 | Cannot move joint at all | Complete rigid |
- In addition, documentation of range of movement, muscle power, quality of life, function, and gait (if relevant) are required
- These assessments should be performed ahead of any planned intervention so the effects of the intervention can be evaluated. For children with cerebral palsy, measures such as the Gross
- For child’s functional capabilities
- Gross Motor Function Classification System (GMFCS)
- Between 6ᵗʰ and 12ᵗʰ birthday
- Children walk at home, school, outdoors and in the community. They can climb stairs without the use of a railing. Children perform gross motor skills such as running and jumping, but speed, balance and coordination are limited.
- Children walk in most settings and climb stairs holding onto a railing. They may experience difficulty walking long distances and balancing on uneven terrain, inclines, in crowded areas or confined spaces. Children may walk with physical assistance, a hand-held mobility device or used wheeled mobility over long distances. Children have only minimal ability to perform gross motor skills such as running and jumping.
- Children walk using a hand-held mobility device in most indoor settings. They may climb stairs holding onto a railing with supervision or assistance. Children use wheeled mobility when traveling long distances and may self-propel for shorter distances.
- Children use methods of mobility that require physical assistance or powered mobility in most settings. They may walk for short distances at home with physical assistance or use powered mobility or a body support walker when positioned. At school, outdoors and in the community children are transported in a manual wheelchair or use powered mobility.
- Children are transported in a manual wheelchair in all settings. Children are limited in their ability to maintain antigravity head and trunk postures and control leg and arm movements.
- Gross Motor Function Measure (GMFM)
- The GMFM is a standardized observational instrument that has been designed and validated to measure change over time, helping to summarize this with a single score that can then be compared to chart their progress.
Level 1
Level 2
Level 3
Level 4
Level 5
Adult assessment of spasticity for post spinal cord injury or cranial strokes
- Doing nothing if the spasticity is not troublesome or if its leg stiffness is used to allow walking;
- Prevention of complications such as contractures through stretching, evidence for which is lacking, and positioning at rest;
- Prevention of spasticity through amelioration of any exacerbating factors such as pain, infection, or anxiety;
- Learning self-control, for instance reduction through relaxation;
- Simple single drugs, such as baclofen or gabapentin;
- Combinations of drugs;
- Using intra-muscular botulinum toxin in conjunction with rehabilitation therapy for focal spasticity;
- Intra-thecal baclofen delivered by an implanted, programmable pump for more general spasticity especially of the legs;
- Destructive procedures such as tenotomies and phenol injection of nerves.
Controversy
- At present, the main source of controversy in spasticity management concerns the role of SDR for children with spasticity.
- Concern has been voiced because it is irreversible and can make function worse.
- Rigorous patient selection is therefore key.
- Today, most authors accept the role of SDR for children with moderate levels of disability (GMFCS levels 2 and 3)— for whom it can improve function and mobility.
- Even for this group, there remains controversy.
- The main critique of the SDR literature is that studies are usually single- centre, small volume, and not case- controlled.
- This surgery is low- volume and highly specialist which makes larger, case- control studies a challenge.
- Some authors also cite a lack of long- term outcome data, despite there being an increasing number of reports of up to 26- year follow- up
- Others cite a supposed high risk of paralysis or incontinence, which has not been proven in the literature.
- Some advocate SDR for more disabled and even wheelchair- bound children (GMFCS levels 4 and 5) as a replacement for ITB therapy.
- For this group, the indications and goals of treatment are different because these children will often not achieve independent walking
- They are also more likely to have mixed spasticity and dystonia, which can make the outcome less certain.
- Some advocate offering SDR instead of ITB for GMFCS level 4– 5 children to help with personal hygiene and ease of movement, because
- SDR means that they will not require the regular hospital reviews and pump refills/ replacements over the subsequent years.
- This has not been proven to be the case, however, and is certainly an area for future clinical trial research.
- For this group SDR can also remove/reduce their ability to stand for transfers with associated negative consequences for quality of life.
- In addition, there is interest in whether SDR could have a role in
- Genetic conditions,
- Acquired injuries (e.g. spinal trauma or postinfectious),
- Patients with hemiplegia
- RCT for physio without and with after STR
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