Tethered cord (tethered spinal cord) syndrome is a condition in which the spinal cord is fixed by abnormal connective tissue from its lower end. It may be present at birth or may appear later. Abnormally located band at the lower end of the spinal cord causes the movement of the spinal cord to be restricted and stretched. Tension may increase in movements where the spine is bent forward and backward. This problem is usually due to problems in the stage of embryological development called secondary neurulation. It may also be associated with spina bifida occulta, tumors, lipomas, and infections.
Depending on the age of the person and the underlying cause, the signs and symptoms of tethered cord syndrome may differ. Pain in the groin area and legs, muscle strength and sensory disturbances, urination problems, orthopedic abnormalities and skin findings may be seen. Treatment is mostly surgery.
Congenital (Congenital, Primary) Tethered Cord Syndrome
The filum terminale is the tissue that extends from the end of the spinal cord to the rump bone (sacrum). During neural development, the lower end of the spinal cord facilitates the ascending of the conus medullaris. In secondary neurulation, improper development of the neural tube can cause precursor cells to proliferate and differentiate, thickening the filum terminale. This thickening prevents the conus medullaris from rising and the spinal cord elongates more than normal. If the spinal cord is overstretched, signs of injury may occur.
Lipomas at the lower end of the spinal cord can also cause tethered cord syndrome.
Other disorders in the development of the spinal cord may also be associated with tethered cord syndrome. Spina bifida occulta, split cord malformation (diastematomyelia and diplomyelia), neuroenteric cysts can be counted among these.
Secondary Tethered Cord Syndrome
If spinal cord stretching occurs due to subsequent factors such as infection, fibrotic scarring, surgical complication, tumor, it is classified as secondary tethered cord syndrome.
When the spinal cord is stretched, blood circulation is impaired, nerve cells cannot receive as much oxygen as they need, and symptoms occur.
In the congenital type, as the child grows, the severity of the stress increases and begins to give symptoms. Due to variations in the growth rate of the spinal cord and spine, the rate of progression of the complaints is variable. While signs and symptoms are noticed at birth or in infancy in some individuals, they may not cause complaints until adulthood in others.
- Pain in the buttocks and groin radiating to the legs; It can be increased by sitting for a long time and leaning forward.
- Muscle weakness (not in myotomal pattern), increased deep tendon reflexes, involuntary muscle spasticity
- Numbness, loss of sensation in the groin area, legs
- An electric shock sensation that spreads through the spine and progresses to the arms and legs, usually triggered by tilting the head forward (Lhermitte’s sign)
- Excessive activity in bladder muscles, feeling of urgency, decreased urine flow, urinary incontinence
- Club foot deformity, leg muscle wasting, thinning, scoliosis , increased lumbar cupping, gait abnormalities
- There may be symptoms such as cutaneous lipoma, dermal sinus, cutaneous hemangioma, differences in the lines of the buttocks, and abnormal pitting.
What Diseases Can It Be Confused With?
Lumbar hernia , lumbar slippage, peripheral nerve diseases, spinal cord diseases (tumor, infection, etc.) may give similar findings. The features that distinguish the symptoms of tethered cord syndrome from hernia or sciatica are:
- Muscle strength and sensory disturbances do not occur in a normal myotomal / dermatomal pattern.
- Coughing and sneezing do not cause an increase in complaints.
- Lying on your back does not relieve pain.
- The straight leg raise test does not increase pain.
Patients with suspected tethered cord syndrome based on a medical history and physical examination are usually diagnosed with MRI of the lumbar spine. On MRI, the conus medullaris is located below (below the L2-L3) level, the philum is thicker than 2 mm, and the presence of fat in the filum are characteristic features. However, the disease can also be found in those whose conus medullaris is at normal L1-L2 level. EMG allows to evaluate nerve functions. In infants, the position of the conus medullaris can be determined by ultrasonography.
The treatment of tethered cord syndrome is usually surgery. The band causing tension is released. In the early period, the results of the surgery are better before the symptoms get worse. If the surgery is delayed, bladder problems and neurological findings may be permanent. Nearly half of people who refused surgery had worsening of symptoms. However, preventive surgery is not recommended in asymptomatic tethered cord patients who do not cause any symptoms.
If the tethered cord associated with the lipoma has developed, rapid weight gain may aggravate the symptoms. If the symptoms are mild in these patients, weight loss may provide treatment.
Spinal cord strain may be exacerbated by position. Posture training can be useful in this regard. Balance, position sense and muscle strengthening exercises can be applied to people who develop gait disorders.