What Is Myelomeningocele?

At 18-21 weeks of embryonic development, neural tube closure defects result in laminar hypoplasia, and the spinal cord and meninges swell out of the spinal canal through the defective laminae. At present, spinal meningocele is considered to be caused by a variety of factors. Including surrounding environmental factors and genetics.

Hu Peng	(Resident)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University
Du Jianxin	(Chief physician)	Department of Neurosurgery, Xuanwu Hospital, Capital Medical University

Spinal meningocele (myelomeningoeele, MMC) is a congenital malformation of the nervous system. Due to congenital laminar dysplasia, the spinal cord and meningeal bulge out of the spinal canal through the laminar defect. The global morbidity rate is about 0.05% to 0.1%, which is one of the important causes of neonatal disability and death. It is conservatively estimated that 300,000 people get sick every year, resulting in 41,000 deaths and 230,000 disability. China is a high-incidence area with an incidence rate of about 0.1% to 1.0%, which seriously damages the physical health of children in our country and brings huge economic and spiritual burdens to their families.

Western Medicine Name: Spinal meningocele
English name: myelomeningoeele, MMC

Affiliated Department: Surgery-Neurosurgery
Contagious: Non-contagious

Causes of Spinal Meningocele

Pathogenesis and pathophysiology of spinal meningocele

Spina bifida spinal meningocele bulge genetic research is currently mainly in the animal experimental stage. By feeding pregnant rats with retinoids, 15.5 d, 17.5 d, and 19.5 d pregnant embryos were obtained, and Western blotting was used. And immunohistochemical detection of Eed, Rnf2, Su212, and H3k27me3 protein expression and polycomb group protein expression in the retinoid group and control control group, the results suggest that multi-comb histone may be involved in spina bifida spinal cord Swelling. Cossais et al.'S functional analysis of the formation of SOXl0 structure in the neural tube of chicks suggests that the SOXl0 structure is involved in spinal cord development and may be related to spina bifida spinal meningocele; although there are many similar animal experiments, spina bifida spinal meningocele There are relatively few studies on human genetic testing, and the pathogenesis genes are controversial. Isik et al. Reported that the gene of chromosome 7 (7p36) homologous gene HIxB9 is the main pathogenic gene of spina bifida spinal meningocele by genetic testing of children with spina bifida spinal meningocele with anorectal deformity and zygomatic deformity.

Clinical classification of spinal meningocele

According to pathology and morphology, and combined deformed tissues, they can be divided into three categories.

Spinal meningocele

A cystic mass occurred in the midline of the back. The size varies, the width of the base varies, and the surface skin is mostly normal. The deep surface film of the subcutaneous layer is the spinal dura mater, forming the lining of the bulging sac. The capsule is filled with cerebrospinal fluid, no nerve tissue, or only a thin fibrous band attached to the surface of the spinal cord. The capsule neck is usually thin. The spinal cord has a normal structure. In a few cases, there is a scar-like change in the outer epidermis.

Spinal meningocele

The meningeal sac bulges from the lamina rupture, varies in size, and has a wide base. The sac is lined with a dura mater and the sac neck is generally wider. There are two cases of capsule contents: one is accompanied by a small number of nerve root processes into the capsule and attached to the capsule wall. Another type of spinal meningocele of the lumbosacral region, the spinal cord and its nerve roots enter and attach in the capsule. Some of the spinal cord and nerve tissue burst into the capsule and then curl back into the spinal canal and dura mater. The sac is filled with cerebrospinal fluid, and sometimes the sac is divided into small rooms or sacs by fibrous bands. The spinal cord and nerve tissue protruding into the sac may have only loose adhesion to the sac wall, but some are tightly adhered to the sac wall, or even inseparable. The degree of nerve damage therefore varies widely. -In some cases, the skin on the surface of the mass is thin and scar-like, and in some cases, it is a squamous cell carcinoma. Spinal meningocele and spinal meningocele are sometimes combined with lipomas, which are called lipomatous meningoceles or lipoma spinal meningoceles.

Spinal meningocele exposed or spinal bulging

Rare. The spinal canal and dura mater are widely open, and the spinal cord and nerve tissue are directly exposed. May have degeneration of nervous tissue. There is fashion covered with a layer of bright film. ^[1]

Clinical manifestations of spinal meningocele

Spinal meningocele

When the baby is born, the midline of the back, neck, chest, or lumbosacral region are visiblecystic mass. From jujubes to huge. The mass is round or oval. Most bases are wide, and a few are banded. The surface skin is normal, sometimes scar-like, and thin. Those who have had ulceration have granulation or infection on the surface. Cerebrospinal fluid flows from the surface of the mass. When the baby cries, the mass increases, and when the pressure mass is pressed, the front door swells. It shows that the bulging mass is in communication with the subarachnoid space. Mass transmission test, pure meningocele, high degree of light transmission, and those containing spinal cord and nerve root. Sometimes there are visible shadows inside the mass. Such meningoceles and spinal meningoceles combined with lipomas have the appearance of fat mass. Its deep side is a meningocele.

Spinal meningocele nerve damage symptoms

Pure meningocele can be without neurological symptoms. Patients with spinal meningocele and deformities and degeneration of the spinal cord end, forming spinal cavities, the symptoms are more serious, with different degrees of paralysis of the lower limbs and incontinence. Severe neurological damage caused by lumbosacral lesions is far more than cervical and chest lesions. Spinal meningocele itself constitutes a tethered spinal cord. With the increase of age and length, the spinal cord tethering syndrome becomes more severe. Spinal cord exposure usually displays severe neurological symptoms and is also determined by the degree of spinal deformity.

Spinal meningocele other symptoms

A few spinal meningoceles extend into the chest, abdomen, and pelvis, with symptoms of mass and compression of the internal organs. Some children with meningocele have hydrocephalus and other malformations, and corresponding symptoms appear.

Spinal meningocele disease hazards

Myelomeningocele can cause local skin ulcers, infections, and even subarachnoid and intracranial infections, which can cause serious neurological complications and sequelae, including: cognitive dysfunction, epilepsy, and limb paralysis. Spinal meningocele can cause neurological symptoms such as lower back pain, numbness of the lower limbs, weakness, dysfestation, and habitual abortion. Can seriously affect the quality of life of patients.

Diagnosis and differential diagnosis of spinal meningocele

Spinal meningocele diagnosis

1) According to the characteristics of the above clinical symptoms, a diagnosis can generally be made. The light transmission test can be used as a diagnostic reference. The most important diagnosis point is that a bulging mass is found in the midline of the baby after birth, and it expands with age, and the corresponding symptoms of neurological damage.

2) Plain radiographs of the spine show changes in spina bifida. For those with bulging cysts extending to the thoracic cavity and abdominal cavity, the intervertebral foramen are often enlarged. For those protruding to the pelvic cavity, the sacral canal is significantly enlarged.

3) CT and MRI scans show pathological conditions such as spina bifida and deformities of spinal cord and nerves, as well as local adhesions.

Differential diagnosis of spinal meningocele

It needs to be distinguished from lipomas, teratomas, dermoid cysts, malignant tail tumors, and chordomas.

Spinal meningocele disease treatment

In principle, such diseases are suitable for surgical treatment. The main points of the operation are: 1) removal of the meningocele and repair of soft tissue defects, simple meningocele, which can be cured by this operation; 2) exploration of the spinal cord and nerves bulging into the meningeal sac. Give free, decompose, so that it is also contained in the spinal canal. Can not be removed blindly; 3) spinal meningocele surgery, usually need to expand up and down to expand the laminectomy range for spinal canal exploration and processing, and is conducive to the expansion of nerve tissue; 4) When combined with hydrocephalus and symptoms of increased intracranial pressure, hydrocephalus is performed first to relieve intracranial pressure, and the second step is meningocele resection and repair; 5) Extending to the thorax, abdomen and pelvic Meningeal masses often require laminectomy and combined surgery of the chest, abdomen, and pelvis.

The timing of surgery advocates early surgery. For spinal meningocele of infants and young children, it is necessary to combine their overall condition with the endurance of surgery. Infants and young children who have completely paralyzed lower limbs and incontinence are considered to be contraindications to surgery. At present, the development of anesthesia and microsurgery technology can selectively perform surgery and may achieve good results. ^[2]

Spinal and meningocele disease prevention and health care

Our country has vigorously promoted the oral administration of folic acid drugs or food-fortified folic acid supplementation in women during the first trimester to reduce the incidence of congenital spina bifida spinal meningocele.