Tethered spinal cord syndrome is a complex of pathological symptoms caused by tension of the spinal cord due to fixation of its caudal calving. The condition occurs as a result of congenital malformations, or throughout life due to injuries, neoplasms. The syndrome is manifested by impaired sensitivity and motor function of the lower extremities, dysfunction of the pelvic organs, skin symptoms in the lumbar region. Spinal MR scanning, neurosonography with echospondylography, and ENMG are prescribed for the diagnosis of the disease. Surgical treatment: excision of fixing formations, bypass surgery, craniovertebral bone-dural decompression.
General information
For the first time, tethered spinal cord syndrome (TSCS) was suggested by Funks in 1910, but this term became widely used only since 1976 after the publication of clinical observations by neurologist Hoffman, who described typical symptoms in 31 patients. The incidence of the syndrome is on average 0.8-1.4 cases per 1000 live-born children, according to other data, the prevalence of pathology in the population is 0.1%. In female children, spinal cord fixation is diagnosed more often.
Causes
Tethered spinal cord syndrome can be congenital and acquired. In the first case, it is caused by abnormalities of the spinal canal, which include spina bifida, lumbosacral myelomeningocele, terminal lipomas of the medullary cone, malformations. Children and adults may develop acquired fixation syndrome, which is provoked by the following reasons:
- Scar-adhesive process. About 2/3 of operations on the spinal cord and spine are accompanied by the formation of connective tissue constrictions that violate the normal structure of the spinal canal.
- Post-traumatic changes. Tethered spinal cord syndrome occurs as a complication of severe mechanical damage to the back in an accident, domestic or industrial injuries, as a result of which vertebral fractures occur, spinal membranes are affected.
- Neoplasms. The acquired anomaly is formed with cysts, other benign spinal tumors, and is also a typical consequence of malignant formations of nervous tissue or bone-cartilage structures.
Among the risk factors for congenital fixed spinal cord syndrome, folic acid deficiency is distinguished during the first trimester of pregnancy, which is fraught with serious defects in the formation of the neural tube. Other predisposing factors of the syndrome include the effect of teratogenic factors on the embryo, hereditary predisposition, burdened obstetric history.
Pathogenesis
Normally, when the trunk is bent, the spinal canal is lengthened by 7%, while there is no damage to the spinal tissues due to its stretching. Physiologically, the final thread, which consists of elastin, collagen, and reticular fibers, is responsible for the function of cushioning. The pathophysiological basis of the syndrome is traction of the caudal part of the spinal cord, its persistent fixation at the level of the lumbosacral vertebrae.
In the case of tethered spinal cord syndrome, when the spinal cord is stretched, the blood flow in its distal parts worsens, the electrical activity of cells is inhibited. At the biochemical level, the anomaly is manifested by a decrease in the intensity of oxidative phosphorylation in the mitochondria of neurons. Studies demonstrate the functional nature of the dyscirculatory and metabolic disorders that have arisen, as evidenced by the safety of the spinal pathways.
Symptoms
The manifestation of the syndrome occurs at the age of 1 to 4 years, when children learn to walk, they have a noticeable growth spurt. The second peak of the disease detection occurs during the period of active body lengthening in adolescent children: at 11-15 years old in girls, at 13-18 years old in boys. Diagnosis of a fixed spinal cord is complicated due to the prevalence of latent or low-symptomatic course.
The main group of symptoms consists of neurological disorders caused by damage to the distal spinal cord. Children have weakness in their legs, they are worried about an uncertain gait, clumsiness of movements. Violations of the temperature, tactile, and pain sensitivity of the lower extremities often join. Over time, muscle hypotrophy becomes noticeable, the disproportionality of the body structure.
The second most common is the skin syndrome, represented by visible changes in the lumbar region (subcutaneous lipoma, increased pigmentation, local hypertrichosis). Hemangioma and dermal sinus are less often detected. Gradually, orthopedic disorders appear and increase in children: deformity of the feet, shortening of the limbs, curvature of the spine (scoliosis, kyphosis). Pelvic organ dysfunction is often associated.
Complications
In the absence of treatment, the neurological deficit in children progresses, paralysis occurs in the lower extremities, motor skills are lost. Pelvic disorders are aggravated, which is manifested by incontinence of feces and urine, imperative urge to urinate, girls may have a feeling of a foreign body in the vagina. Up to 37% of patients face severe persistent or paroxysmal pain in the legs and lower back.
A dangerous consequence of the disease is hydrocephalic hypertension syndrome, which is caused by critical disorders of the circulation of cerebrospinal fluid. In children, tethered spinal cord syndrome is usually supplemented by an Arnold-Chiari anomaly. Pathology is manifested by cerebellar disorders (nystagmus, ataxia, dysarthria), multiple lesions of cranial nerves (bulbar, pseudobulbar syndromes), impaired brain stem functions.
After neurosurgical correction, in 5-50% of cases, relapses of tethered spinal cord syndrome are possible, which are more difficult to treat. With incomplete elimination of the fixed spinal area, the recurrence rate reaches 80%. Early postoperative complications include liquorrhea, marginal necrosis of the skin flap, displacement of bone structures. They require revision of the surgical wound.
Diagnostics
The appointment of a pediatric neurologist begins with the collection of complaints and anamnesis of the disease, a detailed clinical examination, checking muscle strength, superficial and deep sensitivity. With fixed spinal cord syndrome, the symptoms in children are nonspecific, therefore, the following diagnostic methods are used to verify the diagnosis:
- MRI of the spinal cord. The study demonstrates the low location and immobilization of the organ cone against the background of a thickened or shortened terminal filament. Indirect signs include non-infection of the posterior wall of the spinal canal, violations of vertebral segmentation, pathological formations in the spinal canal.
- Neurosonography. Ultrasound of the brain and spinal cord is performed in children of the first year of life as a screening method for diagnosing structural abnormalities of the central nervous system. For additional examination of the spine, highly informative echospondylography is prescribed.
- ENMG. Electrophysiological examination of neuromuscular transmission is necessary for the differential diagnosis of lesions of the central and peripheral nervous system in children, to clarify the volume and depth of the lesion.
- Consultations of specialists. In addition to the neurologist, the patient should be examined by other specialized doctors: orthopedist, urologist, functional diagnostics specialist. To resolve the issue of the expediency of surgical treatment of a child, an examination by a pediatric neurosurgeon is indicated.
- Research of biological material. Tissues excised during a neurosurgical operation are subject to biochemical, histological, immunohistochemical studies to clarify the nature of the pathological process, to exclude malignant neoplasms.
Treatment
The main method of treating tethered spinal cord syndrome is the elimination of fixing components, which allows to release the spinal cord, eliminate its pathological tension. To improve the accuracy of neurosurgical operations, intraoperative neurophysiological monitoring systems are used, including registration of CVD, electrostimulation mapping. All surgical methods are combined into 2 groups:
- Complete elimination of fixation. A radical way to correct the syndrome, which restores normal anatomical relationships in the spinal canal. It is used for congenital malformations, small tumors, post-traumatic adhesions.
- Incomplete elimination of fixation. Such operations are performed if the fixing tissues are firmly connected to the structures of the central nervous system, their separation is fraught with neurological deficiency. This is observed in scar-adhesive processes, large lipomas involving the spinal cord.
With severe hydrocephalic hypertension syndrome (edema of the optic nerve discs, impaired consciousness, Evans index more than 0.3), hydrocephalus correction is performed until the spinal cord fixation is eliminated. Liquor bypass operations, endoscopic ventriculocysternotomy, ventricular drainage are performed. With Arnold-Chiari anomaly, children are shown bone-dural craniovertebral decompression, dura mater plastic surgery.
Prognosis and prevention
The probability of cure is determined by the degree of fixation, the cause of the development of pathological changes, the presence of concomitant congenital malformations or organic diseases of the central nervous system in a child. With radical neurosurgical elimination of fixing elements, the prognosis is favorable, it is possible to achieve complete elimination of neurological deficit. Less optimistic prognosis for children with complicated course of the disease, relapses after surgical treatment.
Primary preventive measures: exclusion of teratogenic effects on the fetus, comprehensive obstetric and gynecological care for pregnant women, prevention of domestic and industrial injuries. Secondary prevention consists in the dispensary observation of patients by a pediatric neurologist with the performance of control MRI annually for 3 years, and then every 2-3 years.