05 congenital abnormalities of the spinal cord

7/30/2019 05 Congenital Abnormalities of the Spinal Cord

1/16

Congenitalabnormalities of the

spinal cord

Dr Chamilka Jayasinghe


2/16

Definition

Spinal dysraphism or neural tube defect is a broad

termencompassing a group of congenital spinal

anomalies which result from defective closure ofthe neural tube in early foetal life.(1st four weeksof gestation)

Is the leading identified cause of infant death fromcongenital birth defects.


3/16

Clues as to an underlyingspinal dysraphism

Dermal dimple

Hairy patch of skin

Lipoma

dermal sinus Capillary haemangioma


4/16

Major neural tube defects

1. Spina bifida occulta

2. Meningocele

3. Myelomeningocele

4. Encephalocele5. Anencephaly

6. Dermal sinus

7. Tethered cord

8. Syringomyelia

9. Diastematomyelia


5/16

Classification

1. Closed neural tube defectse.g Spina bifida occulta 5-10% of general

populationBony spina bifida occulta with intact overlying skin

2. Open neural tube defectsA serious congenital anomaly.if the neural tube fails

to fuse

At the skull anencephalus or encephaloceleIf the tube fails to fuse along the spine-

meningomyelocele


6/16

Aetiology

Multifactorial inheritance-genetic & environmental factorsThe risk of an ONTD has been calculated as followsOne previous child with ONTD 2%Two previous children with ONTD 5%Three previous children with ONTD 10%

Sibling with ONTD 2%

CHROMOSOMAL ABNORMALITIES trisomy 13,18 TRIPLOIDY,SINGLE GENEMUTATIONS (10%)

MATERNAL RISK FACTORS IDDM,hypothermia,inutero drug exposure-trimethoprim,valproate,carbamezapine,phenytoin,phenobarbitone anddrugs to induce ovulation ,malnutrition,chemicals,genetic determinants

50% of NTD are related to a deficiency of folic acid


7/16

Spina bifida occulta

Defect in the vertebral arches not

associated with an externally visible sacSpina bifida cystica

Vertebral defect associated with a cysticmass at the back

Meningocele-without cord tissue within thesac

Myelomeningocele spinal neural tissueforms part of sac


8/16

complications Hydrocephalus Meningitis Arnold chiari malformations-cranial nerve dysfunction-occular

muscle palsies, swallowing and eating difficulties and problemswith phonation.

Problems due to associated chromosomal defects Neurological complications:

Paraplegia,functional bladder & bowel problemsSeizuresNeurogenic bladder and renal failure as a sequelaeMusculoskeletal disease-progressive bony & joint

deformities,pathological fractures & muscle atrophyPes cavus ,kyphoscoliosis

Complications following surgery-wound infection,CNS infection,acutehydrocephalus,low IQ

Complications of shunt surgery- ICH/IVH,Bowel perforation andinfection


9/16

Clinical features

Occult NTD

SYMPTOMS AND SIGNS may appear as child grows as more

tension is put on the tethered cord.INITIALLY pescavus, varus deformities,scoliosis

LATER- neurological symptoms pain ,paraesthesia, numbnessof toes and feet, sciatica like,unilateral pain.

Bladder,bowel involvement

Orthopaedic problems- progressive scoliosis,kyphosis,muscleweakness and gait disturbance evident by the time childbegins to walk.


10/16

myelomeningocele At birth-midline defect posteriorly with protrusion of

meninges and cord elements through dural sac is seen. Paraplegia motor level, reflex level and anatomic level of

lesion do not correspond. Thoracic (25%) no voluntary movement of lower limbs

Neck and trunk variable involvementMore severe CNS,cognitive involvement Lumbosacral (75%)High lumbar-hip extensor and abductor and all knee and ankle

movements lostLow lumbar-hip abductors,knee flexors,ankle dorsiflexors

affectedSacral-ankle plantar flexion affected ,anaesthesia in perineal

area


11/16

Prenatal diagnosis

During the first or second trimester- triplescreening of mother (amniocentesis during 16-18wk POG)

alpha feto protein elevated in 85% /acetylcholineesterase

Prenatal sonography

99% of affected fetuses can be detected bycombining these tests.


12/16

INVESTIGATIONS AFTER BIRTH

PLAIN X RAY

USS

MRITo determine extent of neural tissue involvement

CT scan brain to exclude hydrocephalus


13/16

Prevention

Preconception folic acid o.4 mg/d

Intrauterine repair of myelomeningocele- beforedevelopment of significant hydrocephalus withoutchanging the motor outcome.


14/16

interventions Leaking NTD - surgery within 24-48 hours of birth

Hydrocephalus-shunt surgery

Orthopedic surgery- spinal stabilization, tenotomy,tendonrelease , osteotomy

Neurogenic bladder-temporary vesicostomy, urinarydiversion, clean intermittent catheterization


15/16

Multidisciplinary approach tocare

Surgeons

Physicians

Therapists paediatrician


16/16

prognosis

Mortality following aggressivetreatment-10-15%

(most deaths before 4 years of age)

70% of survivors normal IQ

Learning disorders and seizures more

common than in general population

05 congenital abnormalities of the spinal cord

Documents