Cryptogenic spina bifida, the most common form of occult spinal canal closure, is seen in the lumbosacral region, where one or more vertebrae have an incomplete closure of the vertebral plate without bulging of the canal contents. The vast majority of cases of occult spina bifida are asymptomatic for life and have no external manifestations, but are occasionally detected on radiographs. Occasionally, there may be hyperpigmentation of the lumbosacral skin, small umbilical hollows in the skin, excessive hair growth, or a combination of lipomas. A small number of cases of occult spina bifida may have low back pain, mild urinary incontinence and enuresis. Those with symptoms of neurological damage often have local skin changes with intradural dermatomal cysts. According to the clinical symptoms, there are mild, moderate and severe cases, but a significant number of patients with spina bifida do not have symptoms throughout their lives. The symptoms at the onset of the disease include weakness of the lower limbs, mild muscle atrophy, numbness, urination, and sometimes low back pain or leg pain. Mostly one lower limb is involved, but there are cases where muscle weakness occurs in both lower limbs at the same time. Examination reveals the manifestation of peripheral nerve damage, i.e. low muscle tone of the limbs, flaccid mild muscle weakness, and hypoesthesia of the lower limbs and perineum. 2.Intermediate syndrome The above mentioned motor and sensory impairment is more obvious, and it is common to have clubfoot deformity, sometimes low back pain, sciatica or urinary incontinence. 3.Severe disease The lower extremities show obvious loss of muscle strength and even paralysis; sensation is also obviously reduced or disappeared, often accompanied by neurotrophic changes, coldness and cyanosis of the distal lower extremities, and the appearance of trophic ulcers. In some cases, trophic ulcers are often produced in the sacrococcygeal area, and skin sensory disorders are obvious in the sacral nerve distribution area. The lower extremities may show disuse atrophy and loss of Achilles tendon reflex or contracture. Foot deformity may appear as supinated toe foot, bowed foot, inversion or valgus foot. Some patients show complete paraplegia and urinary incontinence, and some are incontinent in both stool and urine. A few have herniated discs or lumbar spondylolisthesis, and some have upper extremity symptoms due to spinal cord embolism. Complications: Complex occult spina bifida is often associated with spinal cord or neurodevelopmental abnormalities, such as local scarring, adhesions, end filament hypertrophy and thickening, which anchor the spinal cord to the vertebrae and limit its upward migration during development, or with chondromas, lipomas, epidermoid cysts, dermatomal cysts, teratomas, arachnoid cysts, cavernous spinal cord ends, nerve root diverticulum formation, gliosis in the spinal cord, or dilated central canal. The condition. Sometimes combined with hemivertebrae, scoliosis, foramina and rib developmental malformations. Diagnosis The diagnosis is based on clinical manifestations such as local skin hirsutism, purple spots, and hyperpigmentation, combined with symptoms of nerve damage. In particular, spina bifida should be considered as the cause of prolonged enuresis or significant urinary incontinence. Spinal radiographs and CT and MRI scans are useful in the diagnosis of the disease. Differential diagnosis: occult spina bifida needs to be differentiated from lumbar disc herniation, lumbar strain, and myalgic spinal cord tumors. Adult-onset cases also need to be differentiated from spinal stenosis, etc. CT and MRI scans can be used to make a clear diagnosis. The examination: 1, spine X-ray radiographs anteroposterior and lateral images of the lumbosacral spine, showing the widening of the vertebral arch root plate defects, spinous process is absent, sometimes presenting multiple spina bifida, or combined with vertebral deformity scoliosis, etc. 2, CT and MRI scans, especially MRI for spina bifida combined with spinal cord embolism diagnosis is more clear. It can show that the end of the spinal cord is shifted down to the lumbosacral junction or sacral canal, and there are local adhesions and other signs. Nowadays, myelography has been replaced by MRI.