The crestal medulla is located in the crestal spinal canal. During growth and development, the crestal spinal canal grows faster than the crestal medulla, so the lower end of the crestal medulla gradually rises relative to the lower end of the spinal canal. Cristal embolism is a condition in which the lower end of the crestal medulla is constrained from rising normally at the end of the spinal canal for a variety of reasons, resulting in a lower-than-normal position. It is one of the main pathologic mechanisms of neurological symptoms caused by a variety of congenital developmental abnormalities, resulting in a series of clinical manifestations known as crural embolism syndrome, also known as crural tethering syndrome. Pathogenesis] Various congenital developmental abnormalities of the crural medulla and crural end can lead to crural embolism, such as occult crural cleft, crural bulge, crural crural bulge, crural end-filament tension, lumbosacral spinal canal lipoma, congenital cysts, and latent hairy sinus, etc. In addition to the aforementioned congenital factors, there are many other causes of crural embolism. In addition to the aforementioned congenital factors, postoperative adhesions in the lumbosacral crural bulge can also lead to crural re-embolization. It is generally believed that the blood circulation of the end of the crural cord is impaired by the crural embolism, which leads to the corresponding neurological symptoms. Clinical manifestations] The clinical manifestations of crural embolism syndrome (crural tethering syndrome) are similar to those of crural schisis, with the following main aspects: 1. Lumbosacral skin changes: lumbosacral skin bulges or depressions, which may be accompanied by secretions or infections; hirsutism; bulging masses …… These predict the presence of occult crural schisis, latent hairy sinus, crural bulge, etc., which may be combined with crural schisis. bulging, etc., which may be combined with crural embolism. 2, lower limb motor disorder: manifested as walking abnormality, lower limb power weakness, deformation and pain, also can be combined with crural scoliosis. Sensory disorder of lower limbs: manifested by abnormal sensation and pain in lower limbs, perineum and lumbar back. 4, urinary and fecal dysfunction: common manifestations are urinary retention, difficulty in urination, urinary incontinence, frequent urination, less than normal amount each time, etc.; constipation, constipation, or incontinence. Diagnosis and examination] Magnetic resonance imaging (MRI) is the main method to diagnose crural embolism, which can not only clarify the presence or absence of crural embolism, but also understand other coexisting pathological changes, such as lipoma, crural longitudinal fissure, etc. X-ray can determine the presence or absence of crural fissure. Combined with urinary and fecal function, urinary ultrasound and urodynamic examination can be performed to evaluate the degree of urinary tract involvement and impaired crural nerve function. 【Treatment】 Surgery to loosen the embolism and remove the lipoma and other lesions. Principles of surgical treatment for crural embolism syndrome] The crural embolism has already undergone organic changes by the time symptoms appear, so we cannot restore it to normal, but can only correct it appropriately so that it does not continue to develop. Symptoms of crural embolism syndrome may be caused by destructive damage to the nervous system, which is usually irreparable, and treatment is simply to keep the damage from worsening. Symptoms may also be the result of irritative or incomplete damage to the nervous system, in which case surgical treatment may have the dual effect of reducing symptoms and preventing progression of the disease. Therefore, the fundamental goal of surgical treatment of crural embolism syndrome (crural embolism syndrome) is to prevent the disease from continuing to progress, and in some patients, motor and sensory function of the lower extremities, and even bowel and bladder function, may be improved as a result. In general, the presence of bowel and bladder dysfunction suggests a poor prognosis. Surgery usually does not improve bowel and bladder dysfunction or deformities of the lower limbs and feet, but it may improve pain and incomplete loss of muscle strength to a certain extent. Deformities of the lower extremities and feet can be partially improved by orthopedic surgery. Therefore, for many patients with crural embolic syndrome, especially children, a combination of crural crural surgery or neurosurgery, urology, and orthopedic orthopedics is required. For patients with normal urinary and fecal function, including those found to have lumbosacral skin changes and sensory and motor deficits in the lower extremities, we recommend early and systematic examination, evaluation, and surgical treatment; for patients who already have urinary and fecal dysfunction, the choice of surgery should be made based on the patient’s general condition and the relevant investigations, and the vast majority of these patients can and do require surgical treatment. The concept of minimally invasive surgery should be implemented, and microsurgery should be performed with neurophysiological monitoring if necessary, in order to completely loosen the embolism as much as possible, to avoid nerve damage, to minimize re-adhesion and embolism, as well as to prevent postoperative wound complications. Postoperative patients are followed up with as much guidance as possible on the prevention and treatment of urinary tract dysfunction, motor and sensory rehabilitation of the lower extremities, and correction of lower extremity deformities. We believe that focusing solely on embolization surgery and neglecting to provide proper guidance for the continued management of these dysfunctions is detrimental to the patient. Relationship Between Crestal Medullary Embolization Syndrome and Crestal Fracture The concept of crestal fissure usually encompasses a wide range of congenital pathologic changes that occur in the crest. These pathological forms include congenital defects in the posterior aspect of one or more segments of the spinal canal, crural bulging of the crestal medulla (dominant crural cleft), crural hypoplasia (i.e., crural embolism), lipomas, cutaneous submerged hairy sinuses either alone or in association with tumors, and longitudinal clefts of the crural medulla. A congenital defect of the posterior aspect of the spinal canal in one or more segments, known as crural closure insufficiency, was the initial source of the term crural cleft and is its recognized diagnostic criterion. Crestal medullary crural bulge is a dominant crural cleft. Occult crural clefts usually take several pathological forms: low crural cone (crural embolism), lipoma, shortened and thickened terminal filaments, fibrous fasciculations, crural longitudinal fissures, cutaneous sinus tracts, crural cavities, dermatomal cysts, and epithelioid cysts. The crural embolism is basically the common pathologic form of the majority of lumbosacral recessive crural clefts, and it is also the main pathophysiologic mechanism of nerve damage caused by crural clefts. Clinicians, especially in China, are accustomed to describing the various pathologic forms of occult crural clefts separately and giving the diagnosis accordingly, such as crural embolism syndrome, lipoma, crural cavernosities, end-filament tension syndrome, crural longitudinal clefts, etc. In fact, these pathologic forms are all common to the majority of lumbosacral recessive crural clefts. However, in reality, the diagnosis of these pathologic forms often does not reflect the full picture of the disease, and the actual pathologic forms may often be more complex and tend to occur simultaneously. In summary, crural embolism syndrome is part of the disease of crural cleft, and it is rare to find a separate crural embolism without crural cleft. Cristal embolism is the main form of pathology causing nerve damage in crural cleft, but in many cases, the diagnosis of crural embolism syndrome alone is often incomplete because it often coexists with other forms of pathology, and recognizing this and performing a detailed analysis of the various forms of pathology with the help of the necessary preoperative investigations is important to improve the outcome of the surgery.