Tethered cord syndrome is a condition where the spinal cord is abnormally attached to surrounding tissue, restricting its movement inside the spinal canal. Normally, the spinal cord hangs loosely and can shift slightly as you bend and move. When it’s tethered, the cord gets stretched, which gradually damages nerve tissue and can cause pain, weakness, and bladder problems. The condition can be present from birth or develop later in life after spinal surgery or injury.
How a Tethered Cord Damages Nerves
The spinal cord is anchored at the brain and floats relatively freely inside a fluid-filled canal that runs down the spine. At the very bottom, a thin band of tissue called the filum terminale connects the cord’s tip to the tailbone. In tethered cord syndrome, abnormal tissue, fat, or scar tissue fixes the lower cord in place too tightly.
This fixation creates a constant pulling force. As the body grows or bends, the cord stretches instead of gliding freely. That stretch produces shear forces inside the cord tissue, which reduces blood flow to the affected area. Nerve cells and the cells that insulate them are highly sensitive to this kind of oxygen deprivation. Over time, the combination of reduced blood flow, oxidative damage, and chronic metabolic stress causes nerve cells to deteriorate and die. This is why symptoms tend to worsen gradually, especially during growth spurts in children or with repetitive bending in adults.
Congenital Causes
Most cases of tethered cord syndrome trace back to a problem that formed before birth. Myelomeningocele, the most severe common form of spina bifida, is the single most common congenital cause. In this condition, the spinal cord and canal don’t fully close during fetal development, and the cord can become abnormally attached to surrounding skin or tissue. Roughly one-third of children born with myelomeningocele will need surgery to release a tethered cord during childhood.
Less obvious birth defects also cause tethering. These include fatty growths (lipomas) at the base of the spine, an abnormally thick filum terminale (the band connecting the cord to the tailbone), tracts where skin tissue extends inward toward the spinal canal, and a rare condition called diastematomyelia where the cord is split by a bony or fibrous spur. In milder forms of spina bifida, such as spina bifida occulta, a thickened band or fatty tissue at the end of the cord quietly anchors it to the canal wall without any visible defect on the outside.
Acquired Causes
Tethered cord syndrome can also develop in people who weren’t born with it. Scar tissue from previous spinal surgery is one of the more common acquired causes. After operations on the lower spine, scar tissue can form around the cord or its surrounding membranes and gradually pull the cord into a fixed position. Spinal infections, spinal tumors, and inflammation of the membranes around the cord can also create adhesions that tether it over time.
Signs in Children
In infants and young children, visible skin markings on the lower back are sometimes the earliest clue. These cutaneous stigmata include tufts of hair growing from a small patch over the spine, dimples or pits in the skin at the lumbosacral area, small fatty lumps, and birthmarks or hemangiomas clustered near the midline. A pediatrician spotting one of these markers may order imaging even before neurological symptoms appear.
As children grow, the pulling on the cord becomes more consequential. In one clinical study, the most frequent symptoms in pediatric patients were lower back pain and lower limb weakness, each seen in 50% of cases. Bladder dysfunction and cutaneous stigmata were the next most common, each appearing in about a third of patients. Children may also develop a spastic or awkward gait, foot deformities (one foot noticeably different from the other), scoliosis, or progressive difficulty with toilet training that doesn’t improve with age. Symptoms often worsen during growth spurts, when the spine lengthens faster than the tethered cord can accommodate.
Signs in Adults
Adults with tethered cord syndrome tend to present differently than children. Pain is usually the dominant symptom, centered in the lower back and radiating into the legs. Leg weakness and pain in the foot arches are common. Adults also report muscle wasting in the legs, numbness or tingling in the lower limbs, and urinary problems including frequency, urgency, a persistent feeling of incomplete bladder emptying, and in some cases incontinence.
These symptoms often develop slowly over years, which makes the condition easy to mistake for a herniated disc, peripheral neuropathy, or simply “getting older.” Adults who had mild, undiagnosed spina bifida occulta as children may not develop noticeable symptoms until their 20s, 30s, or later, when cumulative stretching finally crosses a threshold.
Bladder and Bowel Problems
Bladder dysfunction deserves special attention because it’s both common and potentially serious if left untreated. The nerves controlling the bladder originate in the lowest segments of the spinal cord, exactly where tethering exerts the most force. In one study, 93% of adults with tethered cord syndrome had bladder dysfunction confirmed by testing. The most frequent problem, seen in about 73% of patients, was impaired ability of the bladder muscle to contract properly. In 60% of cases, the bladder muscle had essentially lost its reflex ability to squeeze, leading to incomplete emptying, overflow incontinence, or the need to strain to urinate.
Bowel dysfunction follows a similar pattern. Constipation and loss of bowel control can occur as the nerves supplying the lower intestine and pelvic floor lose function. For many patients, bladder or bowel symptoms are what finally prompt the diagnostic workup that reveals the tethered cord.
How It’s Diagnosed
MRI is the primary tool for diagnosing tethered cord syndrome. The key finding is the position of the conus medullaris, the tapered bottom end of the spinal cord. In a normal spine at any age, the conus sits at or above the L2-L3 vertebral level (roughly the upper part of the lower back). A conus found below this level raises suspicion for tethering. A conus at the L3 level is considered indeterminate, meaning it could be normal or abnormal depending on other findings.
MRI also reveals the cause of the tethering: a thickened filum terminale (anything greater than 2 mm in children is considered potentially abnormal), fatty infiltration, lipomas, scar tissue, or split cord abnormalities. In some cases, the conus position looks normal on imaging but the cord is still functionally tethered. This is sometimes called occult tethered cord syndrome, and diagnosis relies more heavily on matching the clinical symptoms to the imaging findings rather than on a single measurement.
When bladder symptoms are present, urodynamic testing measures how well the bladder fills and empties. This helps establish a baseline before surgery and tracks whether bladder function improves afterward.
Surgical Treatment
The standard treatment for symptomatic tethered cord syndrome is a surgical procedure called detethering or cord release. The goal is to free the spinal cord from whatever is anchoring it so it can move normally again within the canal.
During the procedure, a surgeon opens a small section of the spine at the level of the tethering, exposes the membranes surrounding the cord, identifies the structure causing the tethering, and carefully cuts it. When the cause is a thickened filum terminale, the surgeon locates the band, confirms it’s not a functional nerve root using electrical monitoring, then divides it. In more complex cases involving lipomas or scar tissue, the dissection is more involved. Throughout the surgery, intraoperative neurophysiological monitoring tracks nerve function in real time to protect healthy nerve roots from accidental damage.
Minimally invasive approaches have also been developed. Fully endoscopic techniques use a small camera and instruments inserted through a narrow opening between vertebrae, avoiding the need for a larger incision. These approaches are typically suited to simpler cases like a thickened or fatty filum.
Recovery and Long-Term Outlook
Hospital stays after detethering surgery are generally short, and children can often resume normal activities within a few weeks. Adults typically begin physiotherapy shortly after discharge, with two to three sessions per week being a common recommendation. The pace of recovery varies depending on how severe the symptoms were before surgery and how long the cord was tethered.
Pain and motor weakness tend to improve more reliably than bladder dysfunction. Nerves that have been stretched for years may recover partially or not at all, which is why earlier intervention generally produces better outcomes. In children, surgery performed before significant neurological damage occurs can prevent progression entirely. In adults with longstanding symptoms, surgery more often stabilizes the condition and provides partial improvement rather than full reversal.
Re-tethering is a known risk. Scar tissue from the surgery itself can sometimes create new adhesions that pull on the cord again, requiring a repeat procedure. This is more common after complex detethering surgeries than after simple filum sectioning. Long-term follow-up with periodic imaging and neurological exams helps catch re-tethering before it causes significant new damage.