spina bifida myelomeningocele

NEUROPATORY SCOLIOSIS
From injury of the lower motor neurons

MIELOMENINGOCELE or SPINA BIFIDA

Among all the causes of spinal deformity, myelomeningocele is the most severe and most difficult form to treat; the anomaly is characterized by the herniation of the meninges and the nervous tissue through an opening of the posterior arches of the vertebrae and of the overlying soft tissues (Fig. 36).

Fig. 36 - Meningocele and myelomeningocele.

The disease develops in the fetus during the first weeks of pregnancy due to the incomplete closure of the neural tube, that is the draft of the central nervous system from which the brain and the spinal cord will be differentiated. The risk of mortality of children affected by spinal disease, which in the past was around 70%, has now reduced to 4%; this is mainly due to the multidisciplinary approach to the disease, and for other factors such as the precociousness of the diagnosis, the early closure of the bag, the effective prevention of hydrocephalus (Fig. 37A) (present in 15-20% of cases of spina bifida ) and its treatment (derivation-shunt) (Fig. 37B) as well as the prevention of infections in the urinary tract.
Fig. 37A - Myelomeningocele: clinical aspect of an advanced hydrocephalus. Fig. 37B - Myelomeningocele: intervention of peritoneal ventricle derivation.

At birth, the herniation appears as a red-purple swelling (Fig. 38),

Fig. 38 - Spina bifida with central scar.

sometimes ulcerated and secreting liquor, sometimes covered with intact and thinned skin; this sac can affect different areas of the rachis for a variable length from one to more vertebrae and localize at the cervical and thoracic high (rare) or more frequently at the thoraco-lumbar, lumbar and sacral.

Immediately after the classification of the disease, within the first 48 hours, the patient must undergo surgery to repair the malformation (reconstruction of the dural sac using the juxtaposed muscles at the muscle fascia and suturing the superficial planes).

etiopathogenesis

The cause of the missing and incomplete closure of the neural tube in the fetus is still unknown but it is hypothesized the involvement of 2 factors:

    Environmental, due to lack of folic acid in the period immediately prior to conception and in the first trimester of pregnancy.

    Genetics, due to deficiency in the gene or genes of tetrahydrofolatoreductase, enzyme responsible for the metabolic cycle of folic acid (recent research has shown that the intake of folic acid during pregnancy would decrease by 60-70% the risk of having a son with spina bifida).

Clinical picture

It is different in relation to the level of the lesion and associated diseases, such as peripheral paralysis of the lower limbs and sphincters, peripheral anesthesia, comitial syndromes, epilepsy, hydrocephalus, Chiari malformation, anchored marrow, syringomyelia, neurogenic bladder, hydronephrosis , bladder-ureteral reflux, urinary tract infections, chronic renal failure, incontinence or faecal retention, mental retardation (rare) or frequently learning and attention disorders, foot deformities, congenital hip dislocation, pelvis malformations ( pelvic obliquity) and of the rachis (scoliosis, hyperlordosis, hypercifosis).

In the child with myelomeningocele the onset of scoliosis can be directly related to spinal or congenital lesions (presence of one or more hemivertebras) or variously combined (they can give rise to kyphoscoliosis or to lordoscoliosis).

The treatment of spina bifida scoliosis must generally be aimed at preserving the respiratory function, maintaining stability in the sitting station and controlling the level of the pelvis, always aiming to obtain a straight trunk, centered on the pelvis itself. Congenital, scoliotic, or kyphotic curves become rigid during the first years of life, necessitating early surgical treatment.


Nonoperative treatment

It is not easy to implement it. It is more possible to practice it in subjects with pure paralytic deformities, with wide-radius curves extending up to the sacrum, where an arthrodesis performed at a very young age would result in a very severe spinal growth arrest: at the beginning a bust is preferable late the arthrodesis.

The gessi are not recommended. The bust used is the Milwaukee. Sometimes the child can sleep without a bust because the curve is of a collapsing type and hardly increases during the night. Subaxel busts (Lyonese) are widely used for flexible lumbar and thoraco-lumbar curves. However the busts have the main purpose of postponing the arthrodesis to an optimal age.

Surgical treatment

A general pre-operative examination must bring the child into the operating room under the best possible health conditions: hydrocephalus must be stabilized, the lung fields must be clear, every obstructive obstruction must be corrected, the urine must be sterile.

The arthrodesis area must be accurately determined: it is preferable to artrode at least 1 or preferably 2 vertebrae, beyond the upper and lower limit vertebra. The surgical procedure uses the posterior pathway (CD, ISOLA and others) or the anterior pathway (DWYER, ZIELKE).