What is Tethered Cord Syndrome (TCS)?
Tethered cord syndrome, or TCS, is a condition that is commonly seen in people with a defect known as myelomeningocele and can lead to worsening of physical health. It’s estimated that one-third of these patients may need a surgical procedure in their childhood to release tension on the spinal cord, which is known as spinal cord untethering.
TCS happens when the spinal cord becomes stretched because it is anchored or attached at the base to hard structures inside the body that lack flexibility. These inflexible structures limit the movement of the spinal cord, causing it to stretch. This can happen due to naturally occurring defects like myelomeningocele or because of acquired issues like scar tissue formation.
This excessive stretching can cause changes in the functional ability of the spinal cord, leading to different types of abnormalities. These might include neurological issues (related to the nerves), urological problems (related to the urinary system), issues with the muscular-skeletal system (bones and muscles), or problems with digestion (gastrointestinal).
The term “tethered cord syndrome” came about after a study was published in 1976 where the authors mentioned about 31 patients who had stretched spinal cords. They noticed that symptoms in these patients improved after a surgical procedure that relieved the tension on the spinal cord.
What Causes Tethered Cord Syndrome (TCS)?
The reasons for getting tethered cord syndrome, a condition affecting the spinal cord, can be either from birth (congenital) or developed later in life (acquired). Myelomeningocele, which is a type of spinal defect present at birth, is the most common congenital cause of tethered cord syndrome. Other birth defects that could lead to tethered cord syndrome include dermal sinus tract, a tunnel-like opening in the skin; lipo-myelomeningocele, a fatty mass that attaches to the spinal cord; fibrous or fibro-adipose filum terminale, abnormal tissues at the end of the spinal cord; and diastematomyelia, a split spinal cord.
On the other hand, tethered cord syndrome can also be acquired. It may happen due to spinal cord tumors, which are abnormal growths in the spinal cord, and scar formation, which is the fibrous tissue left behind after an injury and healing process.
Risk Factors and Frequency for Tethered Cord Syndrome (TCS)
Myelomeningocele, a type of birth defect, affects between 0.3 and 1.43 out of 1,000 newborns in the United States. However, this condition is becoming less common thanks to factors like better nutrition for mothers and increased supplementation of folate.
- The incidence of myelomeningocele varies across different regions.
- Folate use and improved maternal nutrition have contributed to a decrease in cases.
- About one-third of children with myelomeningocele will need surgery to release a tethered spinal cord.
- The chances of symptomatic tethering of the spinal cord increase during periods of quick growth.
Signs and Symptoms of Tethered Cord Syndrome (TCS)
Tethered cord syndrome is a condition that affects people of varied age groups differently. For young children and toddlers, symptoms often include issues related to sensory and motor functions. Some common symptoms include sensory loss that’s not specific to a particular region and pain in the back and lower extremities.
However, for older kids and adolescents, their most common symptom is pain. This is usually not associated with any dermatomal abnormalities and is mostly in the lower back region, between the legs, and the lower extremities. These patients may also face issues with sphincter control, leading to problems like incontinence.
Adults with a history of spina bifida present similarly to adolescents with this condition, experiencing a lot of pain and problems with sphincter control. These issues could become more prominent with certain movements of the lower spine. For adults who do not have a history of spina bifida, the primary symptom remains pain, but this is often accompanied by weakness and problems with urination.
Conditions like trauma often lead to these symptoms manifesting in patients. The trauma could be a significant injury involving the spine or could come from everyday activities and milestones like exercise, pregnancy, or childbirth. This is because, in these patients, there is a mild restriction already present in the spinal cord due to the tethered cord syndrome. But the added stress from the trauma makes the condition worse, leading to the decline of nerve functions and difficulties in urination.
But the syndrome affects all age groups in one common way, and that is the problems with the sphincter which lead to issues like recurring urinary tract infections with no other cause, or moments of incontinence in between scheduled catheterization procedures. There may also be bowel dysfunction issues, causing problems like constipation.
Conducting a physical examination is important to diagnose tethered cord syndrome. This starts with a check of the back for signs of spina bifida or the presence of a twisted spine condition. Young babies and infants may only show signs of skin characteristics indicating a blockage condition, like tufts of hair, skin sinuses, birthmarks, and lumps of fatty tissue.
The lower body should be checked for any disorders related to the toes, feet, or hip mobility, as these are common signs of tethered cord syndrome. In patients under a year old, it may be difficult to detect disturbances in sphincter control, but if deformities are noted in the lower extremities or anus, suspicion for tethered cord syndrome should be raised.
Other important parts of the physical examination include an assessment of motor control, sensory perception, deep tendon reflexes, and walking patterns. Deep tendon reflexes and muscle tone could vary. Issues with walking could be due to muscle tightness or deformities in the feet or spine.
Testing for Tethered Cord Syndrome (TCS)
If there’s a reason to believe someone has a tethered spinal cord, a condition where the spinal cord is attached at the base, preventing it from moving freely, a special type of scan called an MRI is the best option for diagnosing it. This type of scan helps doctors see the bottom end of the spinal cord and find any related problems. The normal place for the bottom end of the spinal cord is at the second part of your lower back, or lumbar region. The scan also helps doctors make a plan for surgery.
One part of the spinal cord, called the filum terminale, can also be looked at with the MRI. If it’s thicker than 2 mm, it might not be normal. This is still debated among doctors, particularly when it comes to children. Another technique is to do the MRI twice: once with the patient on their back, and once with them on their stomach. If the spinal cord doesn’t move between these two scans, it might be tethered.
The MRI can also help doctors see other problems related to a tethered spinal cord, like myelomeningocele (a type of spina bifida), lipomyelomeningocele (a fatty mass in the spinal cord), a split spinal cord, or tumors. If the results from the MRI aren’t clear, a different type of MRI called a CISS might be used. This scan can sometimes see things that a regular MRI can’t. Other types of scans, like X-rays and CT scans (which use a computer and x-rays to make detailed pictures of the inside of your body), can be used to learn more about any scoliosis (curving of the spine) that might be present.
If the patient also has hydrocephalus, which is an abnormal buildup of fluid in the brain, the first step is to check if their shunt, a tube used to drain the fluid, is working properly. A faulty shunt can mimic symptoms of a tethered spinal cord. If it’s not working, it needs to be fixed, and the patient can be checked again a few weeks after surgery. If there’s no improvement, then it’s more likely that the patient has a tethered spinal cord.
Checking the function of the bladder can also help in diagnosing a tethered spinal cord. Things like the ability to control bladder movement, total bladder capacity and pressure, involuntary contractions, leak point pressure, sensation, and muscle activity can all be assessed. Deregulated bladder activity is the most common finding, but other symptoms can include uncoordinated bladder muscles, reduced bladder compliance, and decreased sensation. Checking bladder function can also be used as a way to monitor improvement of function after surgery to untether the spinal cord.
Treatment Options for Tethered Cord Syndrome (TCS)
Surgery is recommended for tethered cord syndrome when patients show distinct symptoms and medical imaging shows signs of the disorder.
The procedure to untether the spinal cord starts with a skin cut down the middle of the back, at the same level where the spinal cord connects to a string-like tissue called the “filum terminale”. The muscles along the spine are then gently moved away from the bone of the spine at one or two specific points. A procedure called a ‘laminectomy’ or ‘laminoplasty’ is performed, where parts of the bone in the spine are removed or reshaped.
Once a layer called the dura is visible, it is cut into, and small stitches are placed at the edges. The surgeon then carefully dissects or separates the lower part of the spinal cord until they find where the most caudal coccygeal nerve root (the lowest nerve root in the spine) comes out, which is just above the start of the filum terminale.
The filum terminale is then isolated, and any nerves that are stuck to it are carefully separated. The filum terminale is then cut and removed slightly below where it connects to the spinal cord. If the surgeon is unsure if the filum terminale has been completely separated from the nerve roots, they can perform nerve root stimulation studies during the surgery.
After untethering the spinal cord and checking the nerve roots, the dura is closed tightly and can be tested by performing a Valsalva maneuver, which is when the anesthesia team asks the patient to take a deep breath and gently exhale. Sealants or synthetic covers may be used on the closure. If a laminoplasty was done (where the bone was reshaped), they can use absorbable plates or titanium ones to put the bone back in place. Once bleeding is under control, the incision is closed layer by layer. Monitoring the electrical activity of the nerves during the surgery can be considered as well, as it may reduce risk during the surgery.
Recently, a less invasive option involving a smaller tube-like device has been suggested as an alternative to the traditional method. It has been shown to result in less blood loss and shorter hospital stays. For patients with chronic pain caused by tethered cord syndrome coming back after original surgery, a treatment method called spinal cord stimulation could be effective as well.
What else can Tethered Cord Syndrome (TCS) be?
Tethered cord syndrome can show up in a range of different ways, involving symptoms that affect numerous bodily systems, such as neurological, orthopedic, skin, and urinary. Therefore, there are many possible diagnoses that doctors have to consider when they see symptoms of this syndrome, too many to discuss here.
When doctors use imaging tests to try and pinpoint what’s causing the tethered cord syndrome, they generally categorize the possible causes as either congenital (meaning they’re present from birth) or acquired (developed after birth). The potential congenital causes of tethered cord syndrome could include:
- A dermal sinus tract (a tube-like passage under the skin)
- Myelomeningocele (a type of spina bifida)
- Lipomyelomeningocele (a fat-filled sack in the spinal cord)
- Fibrous or fibro-adipose filum terminale (abnormal tissue at the end of the spinal cord)
- Diastematomyelia (a spinal cord divided in two)
Meanwhile, the possible acquired causes of tethered cord syndrome could include:
- Spinal cord tumors
- Scarring from previous surgery
- Infection
- Bleeding
What to expect with Tethered Cord Syndrome (TCS)
After spinal cord untethering, which is a surgery to relieve tension or stretch on the spinal cord, long-term results are generally good. According to a study, after the surgery, 70% of patients have shown improvement in weakness, with 28% stable and 2% getting worse. When it comes to walking, 79% improved, 19% remained stable, and 3% worsened. Improvement was seen in 63% of patients with muscle stiffness, while 37% stabilized. Nearly all patients reported pain improvement, and 67% showed improved bladder function with 30% remaining stable and 3% getting worse.
However, if a child had bladder dysfunction before the surgery, this might continue for several days or even months after the operation due to temporary nerve injury, but that usually gets better. Most patients regain their ability to urinate within the first one or two months after surgery.
About 30% of patients who had the first spinal cord untethering surgery needed a similar surgery again. Of these patients, 39% required a third surgery and 13% needed a fourth one.
Another notable finding after spinal cord untethering is patients gaining height matching their age percentiles, which was more prevalent in children five years or older.
Possible Complications When Diagnosed with Tethered Cord Syndrome (TCS)
Complications after untethering the spinal cord are rare, with only about 3 to 5% of patients facing worsening neurological or urinary symptoms. Furthermore, post-surgery leaks of cerebrospinal fluid (the fluid surrounding the brain and spinal cord) and symptoms from pseudomeningoceles (abnormal collections of this fluid) are not very common. However, if these symptoms occur, it should signal a potential hidden problem with the cerebrospinal fluid shunt, which is a device used to drain excess cerebrospinal fluid.
Complications can include:
- Worsening neurological symptoms
- Worsening urinary symptoms
- Post-surgery leaks of cerebrospinal fluid
- Symptoms from pseudomeningoceles (abnormal fluid collections)
- A potential hidden problem with a cerebrospinal fluid shunt (drainage device)
Recovery from Tethered Cord Syndrome (TCS)
After surgery, patients usually spend 1 or 2 nights in the hospital. A short period of resting flat in bed, generally for one night, after the surgery can help lessen strain on the healing area. Another part of the post-operation care could include outpatient referrals to occupational therapy and/or physical therapy. This therapy can be helpful for issues with bowel or bladder function, as well as problems with stiff, tight limbs.
Preventing Tethered Cord Syndrome (TCS)
Tethered cord syndrome is a known cause of worsening in individuals with a spinal problem known as myelomeningocele. About one-third of these individuals may need a procedure known as spinal cord untethering during their childhood.
This condition, tethered cord syndrome, may affect different body systems and it can show various symptoms. These can affect the nervous system, the urinary system, the skin, and the bones and joints. The good news is that those who undergo surgery to release the tethered spinal cord usually have positive results. This can lead to improvements in symptoms such as pain, weakness, problems with walking, muscle stiffness, and bladder function.
However, in a few cases, the spinal cord may become tethered again. This means some patients might need to undergo additional surgeries. On rare occasions, surgical complications may occur. These complications could lead to worsening of nerve-related or urinary conditions in about 3 to 5% of patients.
