Spina bifida
Spina bifida is a congenital malformation of the spine, also known as spina bifida, and spinal incomplete closure. Spina bifida is a congenital malformation of the spinal column, also known as spina bifida and spina incomplete. The basic pathology of spina bifida is the absence of the spinal processes and vertebral plates to varying degrees, resulting in incomplete closure of the spinal canal, with the contents of the spinal canal directly adjacent to or even protruding outside the spinal canal. The lesion may involve one or more vertebrae and is often associated with deformities of the nervous system or other systems. Spina bifida is most often seen in the lumbosacral region, to a lesser extent in the cervical segment, and less frequently in other areas.
Clinical manifestations of spina bifida
The overall clinical manifestations of spina bifida can be summarized as follows.
1, local skin manifestations: bulging or depressed skin in the lumbosacral region, which may be accompanied by secretions or infection; hirsutism; bulging large masses, etc.
2, lower limb dysfunction: including sensory disorders of the lower limbs and perineum, such as sensory numbness in the feet, and in severe cases, burns or cuts still do not know the pain; motor dysfunction of the lower limbs, especially the feet and ankles, such as foot drop, toe dragging when walking; deformities of the feet and ankles of the lower limbs, such as horseshoe clubfoot, etc.
3. Urinary and fecal dysfunction: constipation and urinary incontinence are common. Urinary abnormalities are caused by various pathological changes of spina bifida leading to neurogenic bladder, and in severe cases, late stage causes ureteropelvic fluid accumulation and finally leads to renal failure. Renal failure is the main cause of death in such patients.
4. Other manifestations: pain in the lower back, buttocks and lower limbs, etc.
Classification of spina bifida
Depending on the extent of the lesion, those with no obvious bulging of the spinal canal contents are broadly referred to as recessive spina bifida, while the opposite is true for dominant or cystic spina bifida.
(A) Occult spina bifida
Spina bifida without spinal canal contents expansion is called occult spina bifida, which is commonly found in the lumbosacral region, most often involving the fifth lumbar vertebra and the first sacral vertebra. The skin of the lesion area is mostly normal, with a few showing minor skin abnormalities such as hyperpigmentation, dilated capillaries, skin depressions, and local hairiness. However, there may be various pathological changes in the spinal canal at the site of spina bifida, such as scarring, adhesions, emboli, combined lipomas or dermatomal or epithelioid tumors, resulting in compression or involvement of the spinal cord and nerve roots, leading to a range of neurological symptoms.
Occult spina bifida and related lesions causing symptoms in infants and children are often not easily detected. Because infants’ limb and bowel functions are gradually developing and imperfect, and because they do not complain, abnormalities are easily overlooked. It is only when the child’s motor function and/or urinary control of the lower extremities lags significantly behind that of children of the same age, or when the lower extremities are deformed, or when the child still frequently loses urine at school age, that the child is considered to be suffering from congenital spina bifida and related pathologies that have caused damage to the spinal cord and cauda equina nerve roots. In a few cases, parents seek early detection of congenital lesions or early observation of symptoms due to skin abnormalities in the sacral region of the child.
Symptoms associated with occult spina bifida often appear before adulthood, but not all cases of occult spina bifida exhibit symptoms; many patients remain asymptomatic until adulthood and are detected only incidentally on examinations such as radiographs or MRI. In a small number of adult cases, the disease is detected by the presence of urinary incontinence, low back and leg pain, and muscle atrophy, or by the appearance of corresponding symptoms after trauma to the lumbosacral region, for which the patient is seen.
(ii) Dominant spina bifida
According to the pathological relationship between the bulge and the nerve and spinal cord tissue, the following two types are more commonly seen clinically.
1, spinal bulge: the walls of the bulging cystic cavity and the dura mater (and arachnoid membrane) continue, the cyst can be filled with cerebrospinal fluid or other substances, but no neural tissue, the cystic cavity is often formed through the vertebral plate defect in a thin neck with the subarachnoid space in the spinal canal, sometimes this neck is also closed by adhesions. This type is characterized by the fact that the spinal cord and its nerve roots are located in the spinal canal, but there may be coexisting lesions such as spinal cord hypoplasia or spinal cord embolism and intradural lipoma.
The picture on the right shows a large mass in the upper thoracic back of an adolescent female patient; fortunately, it was only a spinal bulge, MRI showed that the spinal cord and nerve roots were not simultaneously bulging, and the patient had no associated neurological symptoms. The prognosis is very good after surgical treatment.
2. Spinal cord bulge: This type is characterized by the dorsal expansion of the spinal cord with the nerve roots in the cystic cavity at the vertebral plate defect, with varying degrees of adhesions to the cystic cavity wall and surrounding tissues, and this type often coexists with severe spinal cord hypoplasia.
In children with manifest spina bifida, a garden-shaped cystic mass is seen in the posterior longitudinal axis of the spine at birth, varying in size from a large cyst with a thin neck to a broad, fornix-shaped base. The mass often increases with age, and the surface skin may be normal, or may be seen as a single or multiple small depressions, or may be thin and translucent, and may be accompanied by other abnormalities such as hydrocephalus.
Depending on the severity of the lesion, children with spinal bulges may have no significant neurological symptoms. In children with severe spina bifida and spinal cord spina bifida, there are various degrees of neurological symptoms and signs. Close examination may reveal weakness of the lower extremities or foot deformities, hypesthesia, unresponsiveness or weak response to acupuncture, urinary incontinence, and constipation.
Diagnosis and treatment of spina bifida
When spina bifida is identified or suspected, lumbosacral radiography and magnetic resonance imaging (MRI) should be performed. x-ray examination is important for understanding bone defects such as vertebral plates; MRI examination is important for clarifying the diagnosis, deciding whether to operate, guiding surgical operations, and reducing nerve damage. In addition, urodynamic examination and urological ultrasound are important for understanding the presence of neurogenic bladder, tracking the function of the urinary tract and giving reasonable treatment.
Almost all cases of spina bifida are treated surgically with the following objectives.
1, removal of the bulging cystic wall to restore a normal or near normal shape.
2. release the spinal cord and nerve root adhesions and incorporate the bulging nerve tissue back into the spinal canal.
3, repair the soft tissue defect, if necessary, turn the lumbar dorsal fascia for repair.
Generally, as long as the child can tolerate surgery and anesthesia, early surgery is advisable; if the wall of the capsule is extremely thin or broken, emergency or early surgery is required. If available, MRI should be performed before treatment. Surgery should not only remove the mass but neglect the release of spinal cord and nerve adhesions and their repositioning, otherwise it will not only fail to achieve the important purpose of nerve protection but also cause difficulties in future treatment. Postoperative care should be taken to keep the wound clean and to observe wound healing.
Patients with cryptogenic spina bifida who have (1) resulting dysfunction of the bowels and lower extremities; (2) lesions such as spinal cord embolism, intradural lipoma, or obvious adhesions that may cause neurological symptoms in the future, should be actively considered for surgery after careful examination. The purpose of surgery is to loosen the embolism, release the adhesions and compression of the spinal cord and nerves, etc., in order to prevent the appearance and aggravation of neurological symptoms.