Meningocele

　　According to pathology, morphology, and associated malformations, it can be divided into the following three categories.

　　Meningocele

　　A cystic mass is formed within the soft tissue inside the vertebral plate that is not closed in the midline of the back, with varying sizes of the cystic sac, uneven widths at the base, and the skin surface is mostly normal. The deep surface of the subcutaneous layer, which is the dura mater of the herniation, forms the lining of the herniation sac and, together with the skin, constitutes a cystic mass. The sac is filled with colorless and transparent cerebrospinal fluid, without nerve tissue, or only a thin fibrous bundle is seen connecting to the surface of the spinal cord. The neck of the sac is usually narrow. The spinal cord within the spinal canal is of normal shape. In a few patients, the skin on the outside of the herniation sac shows scar-like changes.

　　The spinal cord and meninges herniation

　　The meningeal sac protrudes from the vertebral arch defect, with varying sizes, and the base is usually wide. The lining of the sac is the dura mater, and the sac neck is generally wide. The contents of the sac have two situations:

　　(1) One type is accompanied by a few nerve roots protruding into the sac and attaching to the sac wall, that is, there are nerve roots and cerebrospinal fluid components in the sac.

　　(2) Another type is the lumbar sacral spinal cord and meningocele, in which the sac contains the protrusion and attachment of spinal cord and nerve roots. The spinal cord and nerve tissue may protrude into the sac and then curl back into the dura mater sac in the spinal canal. The sac is filled with cerebrospinal fluid, and sometimes the sac is divided into small compartments or small sacs by fibrous bands. The protruding spinal cord and nerve tissue may only have loose adhesion with the sac wall, but some may have firm adhesion with the sac wall, even merging into one and being difficult to separate. Therefore, the degree of nerve damage varies greatly. Some cases have thin skin on the surface of the sac, or scar-like, and in some cases, it presents as squamous epithelial cancer. Some spinal meningoceles coexist with spinal cord and meningocele and lipoma, known as 'lipoma-type meningocele' associated with 'lipoma-type spinal and/or meningocele'. This kind of lesion sometimes has a large mass, with a wide base, and the sac is thickened.

　　3. Exposed or prolapsed spinal cord

　　This type is the most serious and is relatively rare in clinical practice. The vertebral arch defect is wider, the spinal canal and the dura mater are widely open, and the spinal cord and nerve tissue are directly exposed. On the surface, there is only a layer of arachnoid membrane, which generally does not form a cystic mass, and the internal spinal cord and nerve root tissue can be seen to pulsate. There are often degenerative changes in nerve tissue. Sometimes there is a layer of dura mater covering it.

　　Due to congenital factors leading to incomplete closure of the vertebral arch, there is also protrusion of meninges, spinal cord, and nerves into the defect of the vertebral arch. The etiology is not yet clear. This condition is most common in the midline of the dorsal side of the spine, with the lumbar sacral segment being the most common, and a few cases occur in the cervical or thoracic segments. In some cases, there may be protrusion from the paravertebral side through the expanded intervertebral foramen into the lateral side of the spinal canal, or the protruding sac extends to the posterior wall of the pharynx, thoracic cavity, abdominal cavity, and pelvic cavity. Spinal meningocele is generally solitary, and multiple occurrences are rare. Spinal meningocele sometimes coexists with congenital hydrocephalus.

　　During the 18-21st week of embryonic development, a defect in the closure of the neural tube can lead to incomplete ossification of the vertebral lamina, with the spinal cord and meninges bulging outward through the defect into the vertebral canal. It is currently believed that myelomeningoceles are caused by a combination of various factors, including environmental factors and genetic theories.

　　The main complications of spinal meningocele surgery are cerebrospinal fluid leakage and the resulting meningitis, as well as postoperative secondary adhesion. To prevent cerebrospinal fluid leakage, in addition to the strict suture of the dura mater, reinforcing the defect in the lumbar and sacral region with the lumbar and sacral fascia can significantly reduce the incidence of this complication. Postoperative application of antibiotics that can pass through the blood-cerebrospinal fluid barrier can reduce the incidence of meningitis. For cases with increased intracranial pressure after surgery, mannitol/sorbitol and other diuretic drugs should be used. Because the subarachnoid cavity contains blood after surgery, which can cause fever, dexamethasone and other drugs can be appropriately used to prevent hyperthermia and alleviate symptoms. After surgery, the patient should be kept in a lateral or prone position. For those with cerebrospinal fluid leakage, the head should be kept low to prevent excessive cerebrospinal fluid effusion and induce brain herniation. Preventing surgical infection leading to meningocele pyemia is of great importance. For patients with local drainage tubes and cerebrospinal fluid leakage, it is strictly forbidden to use various drugs locally, especially neurotoxic drugs, to prevent accidents.

　　The clinical manifestations of meningocele and myelomeningoceles can be divided into three aspects: local mass, neurological damage symptoms, and other symptoms.

　　1. Local mass: At birth, a cystic mass can be seen on the median line of the neck, chest, or lumbar sacral region of the baby, with varying sizes from dates to large ones. The mass is round or elliptical, with most bases wide and a few strap-like. The surface skin is normal, and sometimes it may be scar-like or thin. When the baby cries, the mass expands, and when the mass is compressed, the anterior fontanelle bulges. In cases where there has been ulceration, the surface defect only has a layer of arachnoid membrane, appearing granulomatous or infected. In cases where there has been ulceration, cerebrospinal fluid flows out from the surface of the mass, indicating that the meningocele sac is communicating with the subarachnoid space. The light transmission test of the mass shows that in simple meningoceles, the degree of light transmission is high; in myelomeningoceles, due to the presence of spinal cord and nerve roots, some may show shadows within the mass; if it is a meningocele or meningocele with spinal cord and meninges combined with lipoma, due to the fat tissue covering the surface and the meningocele sac underneath, the degree of light transmission is lower.

　　2. Neurological damage symptoms: Simple meningoceles may not present with neurological symptoms. In cases of myelomeningoceles with malformations, degeneration, and the formation of spinal cord cysts, the symptoms are often severe, with varying degrees of paralysis of the lower limbs and incontinence of urine and feces. Severe neurological damage symptoms caused by lumbar sacral lesions are much more common than those caused by cervical and thoracic lesions. These neurological damage symptoms include malformation of the feet (such as talipes, genu varum, genu valgum, and foot deformities), muscle atrophy, unequal length of the lower limbs, accompanied by numbness, weakness, and autonomic dysfunction. The spinal cord and meninges malformation itself can lead to further aggravation of the tethered cord syndrome with age and growth. The exposure of the spinal cord usually presents with severe neurological symptoms and is also determined by the degree of spinal cord malformation.

　　3. Other symptoms: A few cases of meningocele may extend to the lateral side of the vertebral canal, the posterior pharyngeal wall, the thoracic cavity, the abdominal cavity, and the pelvic cavity, causing symptoms of compression on adjacent tissues and organs. Some children with meningoceles may have associated symptoms such as hydrocephalus and scoliosis due to other malformations. These symptoms may include the corresponding symptoms.

　　During the 18-21st week of embryonic development, a defect in the closure of the neural tube can lead to incomplete ossification of the vertebral lamina, with the spinal cord and meninges bulging outward through the defect into the vertebral canal. It is currently believed that myelomeningoceles are caused by a combination of various factors, including environmental factors and genetic theories.

　　Pregnant women are advised to increase their intake of folic acid in the early stages of pregnancy to reduce the risk of neural tube defects. Deficiency of folic acid in the early stages of pregnancy can lead to fetal myelomeningoceles. Our country has vigorously promoted the oral administration of folic acid drugs or food fortification to supplement folic acid in pregnant women in the early stages of pregnancy to reduce the incidence of congenital spina bifida and myelomeningoceles.

　　The laboratory examinations for myelomeningoceles mainly include spinal X-ray films, CT, and MRI scans.

　　Spinal X-ray film

　　It can show the bony structural changes of spinal bifida. For those with sacs protruding into the thoracic or abdominal cavity, there is often an expansion of intervertebral foramina; for those protruding into the pelvic cavity, there is often a significant expansion of the sacral canal. Spinal X-ray film is an X-ray photograph examination of the spine. It is used for diagnosing lesions on the spine. Normal values of spinal X-ray film: No abnormal shadows are shown in the X-ray film of the spine. Abnormal results: The X-ray manifestation of intraspinal tumors is: ① The anteroposterior film shows an increase in the distance between the pedicles; the lateral film shows an increase in the anteroposterior diameter of the spinal canal. The extent of the increase is closely related to the size of the tumor; ② Changes in the bone quality of the vertebrae and appendages. The deformation or destruction of the vertebrae is most likely to appear at its posterior edge, presenting as an arched forward concavity; changes in the appendages are most common at the pedicles and vertebral plates, and can also extend to other structures, presenting as deformation, thinning, or even disappearance of the pedicles, absorption and corrosion of the vertebral plates, etc.; ③ Changes in the intervertebral foramina. It is manifested as the expansion or destruction of the intervertebral foramina, which is a common sign of nerve root tumors; ④ Abnormal calcification in the spinal canal. It is seen in a few meningiomas and hemangioblastomas, presenting as patchy calcification shadows; ⑤ Soft tissue mass shadows beside the spine, which are caused by the tumor growing outward through the intervertebral foramen.

　　CT and MRI scanning

　　CT is a comprehensive disease detection instrument, which is the abbreviation of electronic computer X-ray tomography. CT examination is based on the different absorption and transmission rates of X-rays by different tissues in the human body, and uses highly sensitive instruments to measure the human body, then inputting the obtained data into the computer. After the computer processes the data, it can take the cross-sectional or three-dimensional images of the body part to be examined, and detect any small lesions inside the body. It can show pathological conditions such as spinal bifida, malformations of the spinal cord and nerves, and local adhesions.

　　A reasonable diet refers to the nutrition provided by three meals a day, which must meet the needs of human growth, development, and various physiological and physical activities. 'The way to maintain health is to start with food.' Utilizing the nutrition of food to prevent and treat diseases can promote health and longevity. As the saying goes, 'It is better to supplement with food than with medicine.' What is meant by food supplementation is that it can play a role that medicine cannot. People obtain all kinds of nutrients and energy they need through diet to maintain their health. A reasonable diet with sufficient nutrition can improve the health level of a generation, prevent the occurrence and development of various diseases, prolong life, and improve the quality of the nation. Unreasonable diet, overnutrition, or undernutrition can bring varying degrees of harm to health. It is clear that a reasonable diet is extremely important.

　　Patients with meningocele and myelomeningoceles should have a balanced diet, eat more high-fiber foods such as fruits and vegetables, and more high-protein foods such as eggs and soybeans. Pay attention to light diet and moderate exercise. In addition, patients with meningocele and myelomeningoceles should best avoid smoking, drinking, spicy food, coffee, and other irritant foods.

　　1. Treatment Principle

　　In the principle of dealing with such lesions, surgical treatment should always be adopted, and the earlier the surgery, the better the effect.

　　2. Basic Points of Surgery

　　(1) Excision of the meningocele sac and repair of soft tissue defects can achieve cure for patients with simple meningocele through this operation.

　　(2) Exploration of the condition of the spinal cord and nerve roots herniating into the dural sac should be performed under a surgical microscope to free and dissect them, so that they can be returned to the spinal canal, and they must not be removed blindly.

　　(3) For spinal cord and dural hernia surgery, it is usually necessary to expand the vertebral plate incision upwards and downwards to facilitate exploration and treatment of the intraspinal canal, which is conducive to the return of the herniated nerve tissue.

　　(4) For those with hydrocephalus and increased intracranial pressure symptoms, cerebrospinal fluid diversion surgery should be performed first to relieve intracranial hypertension, and then the excision and repair of the spinal dural hernia should be performed in the second step.

　　(5) Spinal dural hernia masses extending towards the posterior wall of the pharynx, thoracic cavity, abdominal cavity, and pelvic cavity often require vertebral plate incision, and it is necessary to invite physicians from related disciplines to perform combined surgery within the posterior pharynx, thorax, abdomen, and pelvic cavity.

　　3. Anesthesia and Position

　　Surgery is usually performed under local anesthesia with reinforced anesthesia, or general anesthesia can be adopted according to the situation. Generally, the prone position is adopted.

　　4. Surgical Incision

　　Straight incisions or transverse incisions are adopted according to the size and shape of the mass. Straight incisions are more conducive to expanding the vertebral plate incision upwards and downwards for exploration.

　　5. Surgical Steps

　　The first step is to make a skin incision, free the dural sac to the vicinity of the vertebral plate fissure. If the hernia sac is too large, it should be pierced first to drain the fluid inside the sac to reduce its volume and to explore the need to expand the vertebral plate incision; the second step is to explore the contents of the sac, free the nerve tissue and handle it according to different situations to meet the requirements for the return of the nerve tissue, and it is also possible to perform an intraspinal exploration at the same time; the third step is to excise and repair the hernia sac, and to strengthen the suture repair of the outer muscular layer. Bone defects do not require repair.

　　6. Surgery for Infants and Young Children

　　When performing spinal cord and dural hernia surgery in infants and young children, it is necessary to comprehensively consider their overall condition and the tolerance for surgery. The infusion and blood transfusion during the operation should be guaranteed, which is very important to avoid hemorrhagic shock during the operation and the risk of life-threatening conditions.

　　7. Management of Special Types of Spinal Dural Hernias

　　For example, those protruding towards the posterior wall of the pharynx, chest, abdomen, and pelvic cavity require combined surgery. The principles of treatment are basically the same.

　　Antibiotics should be used after surgery to prevent infection, and it is necessary to prevent cerebrospinal fluid leakage to ensure the success of the repair surgery.