Spina Bifida

Spina Bifida Spina Bifida and hydrocephalus are the most common anomalies of the central nervous system. Since the bifidus spin is potentially curable, its clinical significance is great.

Epidemiology
SPINA BIFIDA is a malformation of the spine (spinal dysraphism or rachischism) often combined with hernia membranes (meningocele or meningomyelocele) bulging through the bone defect (Fig. 1). It is also often combined with dysplasia of the spinal cord (myelosuppression). When the neural tube is formed not from the actual nerve plate, the spinal cord remains in a primitive form (myeloschisis). This fact causes a different degree of malformations of the neural tube.

The central nervous system occurs at the third week of embryonic development. The nerve plate can be detected in the dorsal part of the midline of the embryo at the initial stage, within a few days it protrudes forming neuronal folds. Neuronal folds deepen and move to the middle line forming a neural groove.

The pathogenesis of spinal dysraphism is not exactly established. There are two theories: one is a violation of the closure of the neural tube, which was put forward by Reklenhausen in 1886. Another pathogenetic theory is the hydrodynamic advanced Morgani in 1761. In addition to the two theories mentioned, there is a theory of excessively accelerated growth or growth arrest as the cause of the dysphasia of the neural tube.

The frequency of myelomeningocele varies from 1 to 2 per 1000 newborns. The frequency of repeated childbirth with this defect is from 6% to 8%, which indicates the genetic factor of the disease. The higher frequency of this pathology in children born from older mothers. Other factors, such as rubella, influenza, teratogenic substances - are predisposing.

Spina bifida is classified into 2 types:

  • Spina bifida occulta
  • Spina bifida cistica.

The first vice is not combined with the hernia of the membranes and may not manifest itself until adulthood. Meningocele contains only the cerebrospinal fluid, and there are no nerve elements. With myelomeningocele there is both a cerebrospinal fluid and a nervous tissue. Myelocystocele - local dilatation of the central canal with swelling of the posterior wall of the spinal cord. Myelocele - swelling of the spinal cord into the sac through the defect of the bone. In rare cases, the neural tube is absent and the spinal cord remains at the level of a primitive form resembling a nerve plate (spina bifida aperta).

Clinic Spina bifida occult (SBO) often appears in the lumbar region of the neck. Bone defect can be palpated. SBO is often combined with diastematomy, fixed spinal cord, lipomeningocele, non-enteric cyst with dermal or epidermal tumors. These manifestations usually do not give clinical symptoms until the child begins to walk and begins to monitor the acts of bowel movement and urination. Abnormalities of the skin on the back can be detected in 75% of patients with uncontrolled spinal dysraphism. There can be localized hair, capillary hemangiomas, dimpled skin.

Often there is an outflow of cerebrospinal fluid. About 80% of myelo-meningocele occurs in the lumbar and lumbar-sacral area. About half of meningocele is asymptomatic, and the frequency of combination with hydrocephalus is about 25%, whereas in myelomeningocele the frequency of hydrocephalus is 70-80%. Hydrocephalus can develop after the removal of myelomeningocele. In the development of postoperative hydrocephalus, the following mechanisms can result:

Defect of the absorption zone of the cerebrospinal fluid during removal of the bag, Occlusion of meningeal spaces after meningitis, Occurrence of cerebrospinal fluid outflow from the 4th ventricle is caused by the infringement of the medulla oblongata in the large occipital foramen in the Arnold-Chiari malformation. Most children with myelomeningocele have neurological symptoms, more often motor weakness in the lower extremities, and sensitive disorders. When the lesion is located above the L3 segment, complete paraplegia occurs and the patient remains permanently immobile. If the lesion is below the L4 segment, paraplegia does not exist, but there are symptoms of urinary incontinence of varying degrees. The level of motor disorders is determined by the presence of arbitrary movements in the thigh, knee, and foot. Sensitive disorders are checked by injections in the zone of loss to the zone of normal sensitivity.

The survey craniography reveals the divergence of cranial sutures in case of hydrocephalus and lacunar deformation of the skull. Lacunar deformation soon disappears after birth. The same happens with the fingerprints in the thickest parts of the chondra and is more likely a congenital bone dysplasia than the result of an increase in intracranial pressure. Since anomalies in the osseous system can be common, the whole spine needs to be examined. On the overview spondylograms, the intergranular distance, anomalies of adhesion, spina bifida, and anteroposterior diameter of vertebral bodies are evident. Computer tomography (CT) confirms or excludes the presence of hydrocephalus and other anomalies.

With the help of computer tomography, abnormalities of the skin, subcutaneous tissues, muscles, bones and nerves can be identified, however myelography combined with CT is the most informative method in setting a complete diagnosis for spinal dysraphism.

Treatment If there are no contraindications (severe concomitant deformities of other organs or irreversible neurological disorders), in cerebral hernias an operation is performed that consists in the isolation of the hernial sac and its peduncle from the surrounding tissues, the opening of this bag and examination of its contents. When there are in the cavity of the hernial sac roots of the spinal cord they are sharply excreted, immersed in the vertebral canal, the bag is excised and the remains are sewn over the spinal cord. The gap in the arches is closed with a muscle-fascial flap. The operation relieves patients of hernial protrusion, but is less favorable in terms of the reverse development of neurological disorders, which is the result of the irreversible degenerative changes in the spinal cord and its roots.