Spina Bifida Malformations
Being as spina bifida is such a heterogeneous defect, areas from the cervical spine (neck region) to the sacral spine (coccyx region) can be affected, depending on when the neural tube stopped developing and closing properly. The neural tube closes like a zipper during the first 4 weeks of fetal development starting at the cervical area and moving down toward the sacral area. If the neural tube fails to close at any point, all areas south of the point at which the ‘zipper’ gets caught are affected. The sooner neural tube development stops, the more severe the birth defect.
The most common areas directly affected in spina bifida are the lumbar (lower back) and sacral (seat) area of the spine. Vertebrae are numbered from the top downward. There are five lumbar vertebrae (numbered L1 – L5) and five sacral vertebrae (numbered S1 – S5). S5 is the lowest vertebra on a human skeleton.
If the malformation is located in the sacral region, the child’s inner legs and possibly their feet are involved in the disability. They may be able to walk on their own or they may need a little help, although parts of their legs may experience numbness. They may or may not have bowel and bladder control. If the malformation is located in the lower lumbar region (L4 – L5), more of the legs are involved in the disability. The child may be able to walk with crutches, although they may need a wheelchair. It is also likely they will not have bladder and bowel control. If the upper lumbar region is affected (L1 – L3), the child will experience numbness and/or paralysis from the waist down and will probably not be able to walk. They will be wheelchair bound and will not have control of their bowel or bladder functions.
Secondary malformations occur in practically all spina bifida children because of the spinal defect. Chiari malformations are caused when the spinal cord is pulled down through the vertebral cleft, causing the brainstem and cerebellum to be pulled into the sacral area of the spinal column. Complications from this malformation can cause nerve, spinal cord and brain damage at a much higher point than where the main cleft of the spina bifida exists. Hydroencephalus is also a danger with this malformation because spinal fluid is blocked from flowing freely. Those who suffer from spina bifida need to be monitored their entire life for these secondary malformations and for degeneration of the primary malformations.
Dr. Shannon Hamrick discusses in detail about the malformations and outcome of Spina Bifida