Background

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