What are the effects and signs?
Primary neurological impairments
The primary neurological impairments in children with a meningomyelocele are paralysis, sensory loss and a Chiari II malformation (if present) with associated hydrocephalus.
Paralysis and sensory loss
The vertebral column consists of 7 cervical (C1 – C7), 12 thoracic (T1 - T12) and 5 lumbar (L1 - L5) vertebrae connected to the sacrum and coccyx at the base of the spine. Spinal nerves leave the spinal cord and pass out from holes in the adjacent vertebrae.
Cervical nerves supply movement and feeling to the neck, arms and upper trunk. Thoracic nerves supply the trunk and abdomen. Lumbar and sacral nerves supply the legs, bladder, bowel and sexual organs.
The extent of paralysis and sensory loss depends upon the location of the spinal defect, as paralysis and sensory loss occur below that point.
| Level of defect | Degree of paralysis |
|---|---|
| Thoracic (T1 - 12 ) or upper lumbar (L1 - 2) level | Paralysis affects the legs and variable weakness and sensory loss in the abdomen and lower body region. |
| L3 level | Children can usually flex their hips and extend their knees but their ankles and toes are paralysed. |
| L4 or L5 level | Children can usually flex their hips, extend their knees and flex their ankles but have weak or absent ankle extension, toe extension and hip extension. |
| Sacral level (low back/buttocks region) | Children usually only have mild weakness of their ankles or toes. |
All children with meningomyelocele have sensory loss that is greater on the back of the legs than the front. Most affected children have sensory loss around the anus, genitalia and feet.
Weakness and sensory loss may be worse on one side of the body than the other.
Spina bifida is associated with upper limb dysfunction, for example hand weakness and poor fine motor control and coordination.
Chiari malformation and hydrocephalus
Almost all children with a meningomyelocele above the sacral level have a Chiari II (used to be called Arnold Chiari) malformation of the brain. This is a downward displacement of the brainstem (the part of the brain that connects the brain and the spinal cord) and cerebellum into the neck from the skull.
The Chiari II malformation is associated with symptoms caused by compression of the brainstem. Depending upon the age of the child these may include headaches, sensory disturbance, visual disturbance with double vision or nystagmus (uncontrollable jerking movements of the eyes), swallowing problems, alteration in speech, poor coordination on walking, choking, breath holding attacks, brief recurrent respiratory arrests (apnoeic episodes), and opisthotonos (holding the head forced backwards).
Hydrocephalus occurs in the majority of children with a Chiari II malformation.
(90% of children with T1 – T12 or L1, L2 defect; 80% if L3, L4 defect and 65% if L5 or sacral defect).
