Many children in hematology and oncology departments have the “lumbar puncture” program during the treatment process. So here I would like to talk about the knowledge of lumbar puncture from the doctor’s point of view.
“Lumbar puncture” is short for “lumbar puncture”. What is the purpose of lumbar puncture? Simply put, the human central nervous system, in addition to the familiar brain, cerebellum and other tissues, there is a fluid called “cerebrospinal fluid” all over it, just like the city’s water circulation system, which maintains the normal function of the central nervous system. When lesions occur in the central nervous system (meningitis, encephalitis, tumors spreading to the brain, etc.), the nature of the cerebrospinal fluid usually changes as well. So, how do you get cerebrospinal fluid? Cerebrospinal fluid is circulating and is produced by the ventricular cells in the ventricles, passing through the ventricles, into the spinal cord, and finally back into the venous system where it is absorbed. The most convenient and safest way to obtain cerebrospinal fluid is by puncturing the lumbar spine of the body compared to other locations where cerebrospinal fluid flows. As long as the patient is in the proper position, the needle is inserted from the lumbar spine and the tip of the needle only needs to pass through some skin, subcutaneous tissue and ligaments, usually without touching important nerves or blood vessels, to enter the “subarachnoid space” (where the cerebrospinal fluid circulates) and the cerebrospinal fluid flows out.
Does a lumbar puncture hurt or not? This is the main concern of the young patient and parents. Of course, there is a completely painless way to do it, which is under intravenous anesthesia. The hospitals I visited in the United States and Hong Kong all use this method, where the child fasted for 4-6 hours beforehand, and the nurse gave the child some short-acting anesthetic drugs intravenously before the lumbar puncture so that the child immediately went into sedation and sleep, and the doctor operated under cardiac monitoring. However, in domestic hospitals, local anesthesia is still the mainstay, and the doctor first uses a relatively fine needle to inject some local anesthetic into the puncture site so that the nerves in the skin and subcutaneous tissue will be less sensitive and the subsequent puncture and operation will not feel too painful.
Chemotherapy is the main treatment for leukemia or lymphoma. However, it is usually difficult for oral or intravenous chemotherapy drugs to enter the central nervous system because there is a barrier called the “blood-brain barrier”, which is like a door that keeps chemotherapy drugs out of the central nervous system, and in this way, the central nervous system becomes a natural “shelter” for tumor cells. In that case, the CNS becomes a natural “shelter” for tumor cells, which is difficult to be killed by conventional chemotherapy, and the tumor cells of leukemia and lymphoma can easily invade the CNS, which is a reason for treatment failure. Therefore, in the Department of Pediatric Hematology and Oncology, while the cerebrospinal fluid is removed by lumbar puncture for laboratory tests (mainly to see if there are tumor cells hiding in the central nervous system), “intrathecal injection” is also performed, which means that chemotherapy drugs are injected through the lumbar puncture needle. The chemotherapeutic drugs are distributed to the CNS with the cerebrospinal fluid, bypassing the “blood-brain barrier” and directly targeting the tumor cells that may be hidden in the CNS to prevent infiltration and kill them. Typically, chemotherapy for leukemia and lymphoma is administered in rounds, and lumbar punctures and sheath injections are repeated with chemotherapy. The number and frequency of lumbar punctures and sheath injections vary depending on the type of disease and stage of treatment, and you should also ask the doctor in charge for details.
So, what should our children be aware of each time they have a lumbar puncture and sheath injection? First of all, it is recommended, if the child is physically able, to take a bath a day in advance, especially to wash the skin of the lower back thoroughly to facilitate local disinfection before the doctor’s operation. Then, it is not advisable to eat too much before the operation. If the doctor feels it necessary (if anesthesia is required), he/she will inform the child to fast for a few hours or to take medication with only a small amount of water. If you can get a local pain relief cream (I don’t think it is available in China yet), you can also apply some to the puncture site beforehand to reduce the pain. When doing the lumbar puncture, I hope that the child will be obedient, lie on his side, do not move around, lower his head close to his chest, bend his knees close to his stomach, that is, curl his body into a shrimp, this position can fully open the lumbar space, easy to operate and reduce the injury. After the lumbar puncture and sheath injection, according to the doctor’s instructions, lie flat on the bed for about 4 hours, do not put pillows, do not lift the head, if there is no discomfort, then you can move and eat normally.
Lumbar puncture and sheath injection are medically known as “invasive operations” because they are invasive puncture operations that may have some potential adverse effects, most commonly headaches or localized pain at the puncture site, most of which will resolve on their own. For other possible adverse effects, the doctor will inform the parents before each operation, as well as the necessity of the treatment, and let the parents sign the operation consent form after being informed. With all of the above, I wonder if you are clearer. No matter doctors, parents and children, all should be well prepared before lumbar puncture and sheath injection, I believe that this way, the operation will become smoother and safer, and it will not become as scary as imagined.