Definition
Spina Bifida is a congenital disorder in which the 2 halves of posterior vertebral arch fail to fuse
Dysraphism is maldevelopment of neural tube and skin
Cutaneous signs
Tuft of hair
Pigmented naevus
Scarred area
Post midline dimple / sinus
Lipoma
Tail
Associations
Cord tethering
Diastematomyelia
Cysts or lipoma of cord
Hydrocephalus
Arnold Chiari Malformation
- distal tethering may cause herniation of brain stem / cerebellum obstructing CSF flow
Epidemiology
10-30% of population
- 25% no cutaneous stigmata
- clinically significant dysraphism is rare
Embryology
Germ cell problem
- can get deformity in all three germ cell lines
1. Somatic Ectoderm
- cutaneous dysplasia
- hairy patch, naevus, dermal sinus
2. Mesoderm
- vertebral dysplasia
- split in spinous process and laminal defects
3. Neuroectodermal
- neural tube
- myelodysplasia, intramedullary and extramedullary growths associated with dysraphia
Commonest forms
Diastematomyelia
- spinal cord / filum terminale / both
- split sagittally by bony or fibrocartilaginous septum
Lumbosacral lipoma
Meningocele manque
- loop of nerve root or trunk becomes adherent to dura
- then returns to cord or cauda close to origin
Arachnoid / Dermoid cyst
Tethered Cord
- tight filum terminale leading to tethered cord
- conus at level of coccyx in fetus
- upper border of L3 at birth
- upper border L2 by 5 years
Hydromyelia
Clinical Presentation
Vast majority asymptomatic
Any age from birth to maturity with
- short, wasted leg
- small foot
- cavovarus deformity
- paralytic valgus foot deformity
- trophic ulceration
DDx
Hemihypertrophy or hemiatrophy if small limb
CMT
CP
Ultrasound
Investigation of choice < 6 /12 presenting with midline lumbar dermal anomalies
X-ray
>6/12
- varying degrees of spina bifida
- vertebral anomalies
MRI
Management
Principles
Recognise the condition and arrest any further neurological deterioration
- MRI spine
- If find tethered cord etc needs neurosurgical opinion on whether release of cord worthwhile
Address foot deformity along typical lines once neurological deformity stabilised