Definition
CP is a permanent disorder of movement and posture
- non-progressive
- brain injury before the age of two years
Strict definition excludes familial & progressive congenital problems & those acquired in childhood as a result of head injuries
Incidence
2-3 per 1000 live births
Higher in
- premature and low birth weight children
- low socio-economic group have higher incidence
- more common in advanced countries
(possible increase due to improved survival of premature and low birth weight infants)
Quadriplegia has diminished
Athetosis has been the most dramatic decrease due to
- Rh immunisation
- the drop in erythroblastosis fetalis
- better treatment of jaundiced infants
Most common
- spastic diplegia or hemiplegia
- 65%
Natural History
About 50% have normal intelligence
- 25% end up independent as adults
Walking
- hemiplegics 100% walk
- diplegics 75% walk
- quadriplegics 25% walk
Likely to walk
- sit by 2 years
- stand by 4 years
Aetiology
Prenatal (44%)
Maternal infection (TORCHS)
- Toxoplasmosis
- Rubella
- Cytomegalovirus
- Herpes
- Syphilis
Maternal exposure
- Alcohol
- Drugs
Perinatal (27%)
Hypoxia (accounts for <10% of CP)
Prematurity
Low birth weight
Postnatal (5%)
Meningitis
Head injury
Immersion
Other (24%)
Common Causes
Hemiplegia - obstetric
Diplegic - prematurity
Quadriplegia - anoxia
Athetoid - kernicterus
Prematurity Risk
2500 gms = 0.34%
1500 gms = 14%
<1500 gms = 90%
Pathology
The lesion that is seen in common is "Periventricular Leukomalacia "
Classification
Anatomic and Pathophysiologic classification
It takes at least 2 years to reach a static state
Pathophysiology Classification
Spastic (60%)
- hyperactive reflexes
- develops contractures, bony deformity & ultimately joint dislocation
- benefits from orthotics and surgery
Athetoid (10 - 20%)
- major problems with control of limb position and limb balance
- succession of slow writhing movements
- rarely benefit from orthotics & surgery
- benefit greatly from therapists in terms of self care & occupation programs
Hypotonia (2-5%)
- common in infancy
- most become hypertonic with time
Ataxic (2-5%)
- uncoordinated, unbalanced, wide based gait
Mixed
- important to identify these children as the motion disorder affects the outcome of surgery
- typically spasticity & athetosis with total body involvement
Spastic - motor cortex
Athetoid - basal ganglia
Ataxic - cerebellar
Mixed
Anatomic
(True monoplegia or triplegia probably don't occur)
Diplegia
- lower limbs affected much more than upper limbs
- 75% eventually walk
- IQ may be normal
- strabismus is common
Quadriplegia
- extensive involvement
- low IQ, high mortality
- only 25% able to walk
Hemiplegia
- usually with spasticity
- develop early handedness
- 100% walk regardless of treatment
Mercer Rang's Stages of CP
Stage 1: Dynamic contracture
- secondary to spasticity
- physiotherapy / orthotics / botox
Stage 2: Fixed musculotendinous contractures
- tendon lengthening / transfer
Stage 3: Bone & joint involvement
- osteotomy / arthrodesis + tendon lengthening
Pathogenesis
1. Weakness
UMN lesion / loss of voluntary movement
2. Spasticity
Feature of all pyramidal lesions
- excessive activity of disinhibited neurones / overactive stretch reflex
- hypertonicity with increased DTR
- clonus
3. Contracture
Shortening of the muscle-tendon unit due to failure to keep pace with bony growth
- normally muscles lengthen as bone grows
- as bone grows this worsens spasticity and shortens muscle
- as the muscles don't lengthen get contractures
The sarcomeres add to the muscle at the musculotendinous junction in response to stretch
4. Deformity
Secondary to unopposed muscle contracture
- worse in all cases where muscles cross 2 joints
- psoas, RF, hamstrings, T Achilles
Hip dislocation
- persistent adduction leads to valgus neck
- persistent flexion leads to anteverted neck
- acetabular dysplasia (deficient posteriorly), hip subluxation and dislocation can follow
It is actually uncertain how increased / decreased tibial torsion and increased femoral anteversion appear
Cascade
CNS lesion
Abnormal neurological activity
Spasticity
Reduced muscle excursion and growth
Contractures
Joint instability
Subluxation / Dislocation
Degenerative arthritis
Clinical Features
Spastic Quadriplegia
Usually due to cerebral anoxia
Presentation
- floppy child that won't feed
- choking during feeds - bulbar palsy
- failure to thrive
The primitive reflexes (Babinski, Moro, Parachute) are preserved
Intelligence / vision / hearing affected
- usually mentally impaired
- may have epilepsy
Only 10-20% will walk
- can be delayed up to 7 years
- hip dislocation and scoliosis will develop in non ambulators
Spastic Diplegia
Usually due to prematurity
Lower limb affected more than upper
- all milestones delayed
- most walk by 4 years of age
Can vary from mild toe walker to non-ambulators
Try to improve efficiency of gait
Spastic Hemiplegia
Usually due to obstetric complications
Usually noticed at walking age
- don't swing one arm
- limp with one - handedness
Right-sided form may have speech delay
Seizures common
All walk independently
- aim to improve walking appearance or posture of upper limb
GMFCS
Gross motor function classification system
I Essentially normal, decreased speed and balance
- walk stairs without aids
- some difficulty on uneven ground
II Hand rail up stairs
III Walker inside, wheelchair outside
IV Wheelchair inside and out
V Nil head support
Orthopaedic Management
Goals
1. ADL's
Upper limb / spine
2. Mobility
Walking / transferring
- keeping a GMFCS III walking is crucial
- keeps them out of nursing Home
Ability
- 25% TBI (Total body involvement)
- 100% hemiplegics
- 75% diplegics
Prognostic signs
- > 2 primitive reflexes over 1 year poor sign
- should sit at 2 years, walk at 4 years
- TBI v hemi v diplegic
Guidelines
Expert field
Should never decide on treatment at one visit
- variable nature
Gait analysis lab
- can help decide best options
Single Event Multi Level surgery (SEML)
- avoid birthday syndrome (where children are operated on every year)
- has a psychological impact
Surgery between 4-8 years
- after 8 years tend to develop fixed deformity
Non-operative Management
Physiotherapy
No scientific evidence that it alters the outcome
- very important nontheless
- high contact with parents / children
- keeps joints as supple as possible
Cast correction
Young and mild cases
Bracing
Useful particularly in the equinus ankle where it can be maintained plantigrade in AFO
Botox
Botulinium toxin Type A
- blocks acetylcholine release at NMJ
- 50-60% patients respond well
- for dynamic deformity UL or LL (R1 v R2)
Use
- every 6/12
- peaks at 4/52
- lasts 3-4/12
- at MT junction
- are maps of injection for every muscle in body
Areas
- useful in T Achilles
- useful in hamstrings
- overused in psoas
- very useful in UL
Problems
A. Will only fix dynamic spasticity not fixed contracture of muscle
B. Expense - $500 per IU
Examination
R1 v R2
- R1 is passive range of motion performed slowly
- R2 is passive range of motion performed quickly
- a difference between the two indicates dynamic component
Valium
Potentiates GABA
Intrathecal Baclofen
GABA analogue
Results
Gilmartin J Paed Neurology 2000
- significant improvement over placebo
- indicated for spastic quads / TBI
- pump under abdo wall with reservoir
- into spinal cord
Selective Dorsal Rhizotomy
Best for Spastic Diplegia < 9 without contractures
- need strong legs (as lose some strength with loss of spasticity)
- able to cooperate in rehab
- UL improvement also
Technique
Laminectomy
- stimulate rootlets to find which mediate spinal reflex
- if only these cut, sensation unchanged
- 30% of dorsal rootlets cut
- decreases feedback from stretch receptors
Complications
Spinal deformity
Weakness / parasthesia / bladder problems
Operative Management
Indications
1. Inability to control spastic deformity by non operative measures
2. Fixed deformity that interferes with function
3. Joint instability
Strategies
Stage 1
- physio to help prevent contractures
- botulinum
- splints
- selective posterior rhizotomy
Stage 2
- tight muscles released / lengthened
- weak muscles augmented by tendon transfers
Stage 3
- fixed deformities corrected by osteotomy / arthrodesis