The first stages of the developmental defect of spina bifida occur in the first two to three weeks after conception, before the mother knows she is pregnant. The defect can occur anywhere along the length of the spine, but most commonly occurs in the lower back. The severity of the defect varies greatly from one individual to another, ranging from no noticeable impact to severe paralysis and loss of sensation. Lesions higher in the spinal column result in more weakness of the trunk and possibly the arms as well as the legs.
Because the nerves that control the bowel and bladder are located on the lowest part of the spine, the function of those organs will likely be compromised in all clinically significant cases. Myelomeningocele, the most common type of spina bifida, presents as a sac of exposed meninges or spinal cord membranous coverings, frequently containing parts of the spinal cord and the nerves attached to it. When a baby is born with this condition, it is critical to surgically repair the defect and cover the lesion with skin within the first 24 to 72 hours after birth to prevent infection in the nervous system and further nerve damage. 80% of children born with myelomeningocele will also have hydrocephalus. Hydrocephalus occurs when the cerebrospinal fluid flow is obstructed or blocked and then pressure from that fluid may build in the ventricular system, causing the brain and skull to expand.
It is typically treated by surgical insertion of a shunt to allow the fluid to flow out from the brain. It is important to note that each child born with spina bifida is unique and will have different degrees of clinical symptoms and functional limitations. With the appropriate medical care, rehabilitation, guidance, and encouragement, many individuals with spina bifida may live productive and fulfilling lives.