Intraspinal metastatic tumors

　　The pathways for tumor metastasis to the spinal canal include through the arterial and venous systems, subarachnoid space, lymphatic system dissemination, or direct invasion from adjacent lesions into the spinal canal. Most intraspinal metastatic tumors originate from lung cancer, renal cancer, breast cancer, thyroid cancer, colon cancer, and prostate cancer. Lymphatic system tumors such as lymphosarcoma, reticulum cell sarcoma, and lymphoreticular cell tumor can all invade the spinal cord. Intraspinal metastasis is about 2 to 3 times more common than intracranial metastasis because the tumor in the spinal canal lymph nodes can invade the epidural space through intervertebral foramina, and tumor destruction of the vertebrae can also compress the dura mater. Acute leukemia, especially acute lymphoblastic leukemia, can infiltrate the dura mater, spinal cord, or nerve roots, and can also infiltrate the blood vessels of the spinal cord.

　　Intraspinal metastatic tumors can be distributed in any segment of the spinal canal or spinal cord, but the most common is the thoracic segment. The majority of spinal canal metastases occur in the epidural space of the spinal cord, and some destroy vertebral bone such as vertebral bodies and adjacent structures, causing compressive fractures. Intramedullary and intradural spinal canal metastases are very rare, and tumor cells can spread into the spinal cord through nerve roots or subarachnoid space.

　　Due to the rapid development of the disease, patients with intraspinal metastatic tumors may present with incomplete or complete paraplegia when seeking medical attention.

　　1. Incomplete paraplegia:Incomplete loss of sensation, movement, or sphincter function below the level of spinal cord injury, with partial retention of sensory and motor functions in the lowest spinal segment, the sacral segment, including sacral sensation, the connection between anal mucosa and skin, and partial retention of the voluntary contraction of the anal external sphincter.

　　2. Complete paraplegia:Most vertebral fractures are caused by trauma, with severe injuries, many complications, and poor prognosis, even life-threatening, manifested as local pain, inability to move, severe cases with nerve compression leading to paralysis. If complete loss of sensation, movement, and reflexes below the level of injury, and complete loss of bladder and anal sphincter function, it is called complete paraplegia.

　　The clinical history of intraspinal metastatic tumors often has no specificity. Only when symptoms of spinal cord compression occur will patients seek medical attention and undergo targeted spinal cord examinations. At this time, it is difficult to determine the primary lesion in some cases, so there is no accurate statistical data on the time from the primary lesion to the intraspinal metastasis.

　　Since the majority of intraspinal metastatic tumors grow infiltratively in the epidural space, they are prone to invade the spinal nerve roots, so pain is the most common initial symptom. Radicular pain starts from the back and often worsens due to actions such as coughing, sneezing, deep breathing, or exertion. Pain as the initial symptom accounts for 96% of intraspinal epidural metastatic tumors, and the pain is more pronounced when lying flat at night. The location of radicular pain corresponds to the tender spots of the corresponding spinous processes, which has certain定位value, and incomplete or complete paraplegia accounts for about 86%, and about 14% of those who have not yet developed paraplegia have severe pain as the main symptom.

　　Early detection and early diagnosis of intraspinal metastatic tumors are the key to prevention and treatment. The following are the preventive measures for metastatic bone tumors.

　　1. Primary prevention:Firstly, the focus should be on preventing the occurrence of primary tumors. Different tumors have different triggering factors, such as smoking can induce lung cancer, etc., and these factors should be avoided as much as possible. Secondly, when a malignant tumor occurs, early detection and early treatment should be done as much as possible to achieve radical treatment of the primary tumor and avoid the source of bone metastatic tumor cells. Thirdly, for patients with a history of primary tumor, they should be vigilant of the signals of bone metastasis and have regular follow-up examinations. Efforts should be made to detect the metastatic lesions early and receive effective treatment.

　　2. Level 2 prevention:Generally, bone metastases are a late manifestation of cancer, and it is rare to have a cure at present. Therefore, the purpose of treating bone metastases is to prolong life, alleviate pain, preserve function, and improve the quality of life of patients.

　　3. Level 3 prevention:Patients with bone metastatic malignant tumors are all in the late stage and can be given supportive and symptomatic treatment.

　　The cerebrospinal fluid dynamics of patients with intraspinal metastatic tumors show varying degrees of obstruction in most cases, and the protein content of cerebrospinal fluid is often increased. The value of spinal X-ray films in the diagnosis of intraspinal metastatic tumors is greater than that of any other intraspinal tumor, and its main feature is osteoporosis and destruction around the spinal canal, with the most common being destruction of the vertebral plates and pedicles, followed by vertebral body destruction causing compressive fractures. CT scanning is mainly valuable for intraspinal metastatic tumors in that it can clearly show the condition of bone destruction around the spinal canal, and through axial bone window images or three-dimensional reconstruction images, it can clearly display the condition of bone destruction at the vertebral bodies, vertebral plates, and pedicles, but is less sensitive than magnetic resonance imaging in displaying the outline of the tumor itself. Magnetic resonance imaging is particularly sensitive to spinal cord and spinal canal lesions, and can first accurately locate and clearly distinguish the structures of the affected segments of the spinal cord, vertebral bodies, vertebral plates, intervertebral foramina, etc. Due to compression by the tumor, adjacent spinal cord edema or deformation is often high T1 and high T2 signals. After contrast-enhanced examination, it is often found that the lesions can be significantly enhanced. In summary, magnetic resonance imaging can accurately detect the location, characteristics of the tumor itself, and the compression condition of adjacent spinal cord and nerve roots, providing the most accurate information for further treatment.

　　Patients with intraspinal metastatic tumors should eat black fungus, tomatoes, carrots, mushrooms, peanuts, lilies, jellyfish, almonds, lotus seeds, pears, water chestnuts, bananas, milk, soybeans, and animal livers, etc. Avoid eating beef, mutton, hairtail, chili, chives, garlic, etc. In addition to appropriately increasing the intake of the above foods, attention should also be paid to avoiding those diet-related tumor-causing factors. In daily diet, it is necessary to avoid eating fruits and vegetables with withered spots, as well as moldy, deteriorated peanuts, grains, and beans. Do not eat pickled, deteriorated fish, meat, sauerkraut, etc. In addition, tumor patients should eat less fried, fried, fatty meat, and other greasy, indigestible foods.

　　Intraspinal metastatic tumors usually compress the spinal cord and nerve roots, causing spinal cord dysfunction or refractory pain, and are often treated palliatively with simple radiotherapy or radiotherapy after surgery. Malignant hematological tumors, such as lymphoma and leukemia, can invade the spinal cord or nerve roots, and radiotherapy is usually the only choice.

　　The treatment of intraspinal metastatic tumors emphasizes comprehensive treatment with surgery, radiotherapy, and biological therapy. The main value of surgery is to alleviate the compression of the spinal cord and nerve roots, and to relieve pain. Try to remove the tumor as much as possible, and make a clear pathological diagnosis to provide a basis for postoperative radiotherapy and chemotherapy.

　　1. Surgical Treatment for Intramedullary Metastatic Tumors

　　1. Indications: Patients who can tolerate surgery in general condition, single metastatic tumor compressing the spinal cord significantly, patients with severe pain who have been treated with various non-surgical treatments without effect, and spinal cord metastases appearing after the primary cancer has been resected.

　　2. Contraindications: Patients with extensive systemic metastases, advanced primary tumor, complete flaccid paraplegia within 72 hours of onset, and those without obvious spinal cord compression even though it is a metastatic tumor.

　　3. Surgical Principles: It mainly involves sufficient laminectomy decompression and, as far as possible, tumor resection to relieve the pressure on the spinal cord. For patients with refractory pain, anterior lateral tractotomy or anterior joint切开术 can be performed. The focus of metastatic tumors is often closely adherent to the dura mater, and only partial or most of the tumor can be resected, and some can only be done for biopsy. Therefore, postoperative radiotherapy or chemotherapy can further alleviate the symptoms.

　　2. Radiotherapy for intramedullary metastatic tumors

　　Whether performed alone or supplemented with radiotherapy after surgery, it has achieved certain effects. Since the normal spinal cord tissue has a very limited tolerance to radiation. Therefore, when choosing the radiation dose, it is necessary to weigh the spinal cord damage caused by high-dose radiation and the spinal cord dysfunction caused by low-dose failure to suppress tumor growth. Under modern radiotherapy equipment and precise planning, the standard dose is 180-200 rad per day, with a total dose of 5700-6100 rad, and the incidence of radiation complications is about 5%. At a radiation dose of 6800-7300 rad, the incidence of radiation complications reaches 50%. Many scholars advocate a total radiation dose of 3000 rad for intramedullary metastatic tumors, with each treatment session being 300 rad, and a total of 10 treatments.

　　3. Chemotherapy for intramedullary metastatic tumors

　　Primarily depends on the type of primary tumor, although some scholars have tried to treat nervous system tumors with catheter chemotherapy, there is no evidence to prove that this method can extend survival rates compared to simple intravenous administration.

　　4. For metastatic tumors invading the vertebral body

　　For patients with extensive destruction and severe vertebral compression fractures, radical tumor resection is usually performed when the general condition is good, and artificial vertebral bodies are implanted with internal fixation techniques. This helps to delay the occurrence of paraplegia and improve the quality of life of patients.