I. Cryptogenic crestal cleft and crestal medullary embolism syndrome [Definition] 1, early embryonic developmental disorders of the vertebral arch, incomplete closure of the spinal canal is called crestal cleft, if the vertebral plate fissure is not large, no spinal canal contents through the defect to expand outside the spinal canal, called cryptogenic crestal cleft. 2, early embryonic cremaster in the vertebral canal roughly equal to the length of the vertebral canal, later the vertebral canal growth is faster, cremaster growth and it is not synchronized. Under normal circumstances, at 20 weeks of embryonic life, the end of the crestal medulla is in the L4 to L5 plane, at 40 weeks in the L3 plane, at birth in the L1 to L2 plane, and in adulthood in the L1 plane. Embryonic cremasteric cleft is often combined with cremasteric malformation, local adhesions, and thick and short terminal filaments, causing the cremaster to be fixed at the lesion site and unable to adapt to the elongation of the cremaster and rise, which is called cremasteric tethering syndrome. Diagnosis】 1. Clinical manifestations The symptoms of occult cremasteric cleft are caused by damage to the cremaster and cremasteric nerve of the affected segment, and are related to the degree of combined cremasteric tethering, compression and nerve damage. (1) Mild symptoms: weakness of lower limbs, mild muscular atrophy, numbness, loss of urine, and sometimes back pain or leg pain. Mostly one lower limb is involved. On examination, there are signs of peripheral nerve damage, such as: low muscle tone, hypoesthesia of lower limbs and perineum. (2) Moderate disease: the above mentioned motor and sensory impairment is aggravated, common horseshoe clubfoot, and sometimes urinary incontinence. (3) Severe disease: the above motor and sensory disorders are further reduced, and even lower limb paralysis occurs, with marked hypoesthesia or loss of sensation, very poor neurotropism, coldness, cyanosis and trophic ulcers in the lower limbs. Nutritional ulcers also appear in the sacrococcygeal region, and contractures occur in the lower limbs after a long time, and paraplegia and urinary incontinence appear. 2, auxiliary examination (1) X-ray crestal plain film: it can show vertebral plate defect, spine protrusion is absent, there is a fashion for multiple crestal cleft, or combined with vertebral body deformity, crestal scoliosis. (2) CT and MRI examination: MRI examination is more accurate and clearer for the display of crestal cleft combined with crestal embolism. The end of the cremaster can be seen to be very low, reaching the lumbosacral junction or the sacral canal, and local adhesions exist. Differential diagnosis】The disease is differentiated from lumbar disc herniation, lumbar strain, myalgia, cremasteropathy, and spinal stenosis. MRI examination can clarify the diagnosis. Treatment principle】Crestal spondylolisthesis combined with crestal medullary tethering is suitable for surgical treatment. Surgery should be performed as early as possible, mainly to expand the vertebral plate, decompression, resection of adhesions, so that the crestal medulla and nerve root release. Cricoid membrane bulge and crestal crestal medullary bulge [Definition] Congenital incomplete closure of the vertebral plate is cremasteric cleft. If the crestal membrane, crestal medulla, crestal nerve from the crestal fissure that is the defect in the vertebral plate is called crestal membrane bulge or crestal crestal medulla bulge. Diagnostic basis] 1, clinical manifestations (1) local mass: at birth, the infant, the midline of the back, neck, chest or lumbosacral can be seen a cystic mass, varying in size, round or oval, most of the base is wide, most of the surface skin is normal. In cases of infection and ulceration, the surface is granulomatous, and in cases of rupture, there is an outflow of cerebral crest fluid. When the infant cries, the mass increases in size, and when the mass is pressed, the fontanelle bulges. If the mass contains cremaster and nerve roots, sometimes there is a shadow inside the mass. If there is a combination of lipoma, the outer surface is a fatty mass and the deep surface is a cremasteric bulge sac. (2) Nerve damage symptoms: simple crestal membrane bulge, there may be no neurological symptoms. The symptoms are more serious in the case of cremasteric cremasteric bulge with cremasteric terminal developmental malformation and formation of cremasteric cavity. Different degrees of bilateral lower limb paralysis and urinary and fecal incontinence may occur. Lumbosacral lesions cause far more severe neurological damage than cervical or thoracic lesions. If combined with cremasteric tethering, the cremasteric tethering syndrome becomes more severe with age. (3) Other symptoms: A few cristae bulge into the chest, abdomen and pelvis, showing symptoms of masses and compression of internal organs. Combined with hydrocephalus and other malformations, the corresponding symptoms appear. 2, auxiliary examinations (1) crestal X-ray plain film: shows crestal fissure changes, the bulging capsule extends into the thoracic and abdominal cavities, the intervertebral foramen is mostly enlarged. The sacral canal is enlarged if it protrudes into the pelvis. (2) CT and MRI examination: it can show crestal fissure, crestal medulla, neurological deformity, and local adhesions. Differential diagnosis】The disease needs to be differentiated from epidermoid swelling in the cervical, thoracic and posterior lumbosacral midline areas. X-rays, CT and MRI examinations can be performed to differentiate. Treatment principle】Surgery is the main treatment, resection of the cremasteric bursa and repair of soft tissue defects. In particular, simple cristae bulge is effective. If there is cremaster or nerve in the bulging capsule, it should be separated and returned to the spinal canal, and should not be removed blindly. When hydrocephalus and high cranial pressure symptoms are present, it is advisable to perform a shunt first and then perform a crista excision and repair in the second stage. To the thoracic, abdominal, pelvic protrusion of the mass, often need to perform laminectomy and thoracic, abdominal, pelvic joint surgery.