The spinal cord is the central column of nervous tissue that extends from the brainstem down the vertebral column, functioning as the primary pathway for transmitting motor and sensory signals between the brain and the rest of the body. Normally, the spinal cord floats freely within the cerebrospinal fluid of the spinal canal, allowing it to move slightly with the body’s growth and movements. Tethered cord syndrome (TCS) occurs when this normal movement is restricted by tissue attachments that anchor the cord to the spinal column. This restriction causes abnormal stretching and tension on the delicate nervous tissue, which can disrupt blood flow and impair nerve function. The surgical procedure known as detethering, or tethered cord release, is designed to free the spinal cord from these abnormal attachments to restore its mobility and alleviate the neurological strain.
Understanding Tethered Cord Syndrome
Tethered Cord Syndrome (TCS) is a neurological condition where the end of the spinal cord, known as the conus medullaris, is held taut by various abnormal tissue attachments. This anchoring prevents the spinal cord from ascending naturally within the spinal canal as the body grows, or from moving freely during normal bending and stretching. This constant, progressive tension leads to mechanical and metabolic strain on the cord, which compromises its ability to transmit signals effectively.
The causes of TCS are often rooted in congenital conditions, meaning they are present from birth, such as those related to spinal dysraphism. Common underlying defects include a thickened or short filum terminale—the fibrous strand at the bottom of the cord—or the presence of fatty tumors called lipomas. Tethering can also be acquired later in life due to scar tissue forming after spinal surgery or trauma.
The progressive stretching of the cord results in a range of neurological symptoms that worsen over time, making surgical intervention necessary. One of the most common complaints is chronic pain in the lower back that can radiate down the legs, sometimes aggravated by positions like bending or sitting. Patients may also experience progressive weakness, numbness, or loss of feeling in the legs and feet, leading to changes in gait or foot deformities.
A significant sign of TCS is a change in bladder and bowel function, which can manifest as incontinence or difficulty emptying the bladder. In children, physical markers on the lower back, such as skin dimples, hairy patches, or fatty lumps, often suggest an underlying tethering issue. The purpose of detethering surgery is to stabilize or improve these neurological deficits by releasing the physical strain on the spinal cord.
The Surgical Procedure for Detethering
The surgery to release a tethered cord is performed by a neurosurgeon under general anesthesia. The patient is carefully positioned face-down to allow access to the lower back where the tethering is located. A small incision is made along the midline, and the surgeon removes a section of the bony vertebrae, known as a laminotomy or laminectomy, to access the dura mater, the protective covering of the spinal cord.
Once the dura is opened, the surgeon uses high-powered magnification and specialized microsurgical instruments to identify the exact point of attachment. This tethering structure could be a tight filum terminale, an embedded lipoma, or dense scar tissue from a prior operation. The goal is to meticulously dissect the spinal cord and its delicate nerve roots away from these abnormal attachments without causing damage.
A primary safety measure during this complex process is the use of Intraoperative Monitoring (IOM). Electrodes are placed on the patient’s limbs to continuously monitor the electrical activity of the nerves and the spinal cord while the surgeon works. This real-time feedback allows the surgical team to stimulate the nerve roots and confirm the functional integrity of the nervous system before any tissue is cut, significantly minimizing the risk of new neurological deficits.
After the tethering structure has been successfully divided or removed, the surgeon confirms that the spinal cord is able to move freely within the spinal canal once more. The dura mater is then closed securely to prevent cerebrospinal fluid leakage. The overlying muscle, soft tissues, and skin are closed with sutures. The entire procedure can take several hours, depending on the complexity of the tethering.
Recovery and Long-Term Monitoring
Immediately following the detethering procedure, the patient is transferred to a recovery area and then closely monitored in a hospital unit. A typical hospital stay ranges from three to seven days. To minimize the risk of a cerebrospinal fluid leak from the surgical site, patients are generally required to remain lying flat for a period, often between 24 and 72 hours.
Pain management is a primary focus during the initial recovery period, often involving scheduled medications to keep the patient comfortable. The incision site is monitored for signs of infection or leakage. A urinary catheter, often placed before the surgery, may remain for a short time until the patient is mobile and bladder function is stable.
Once home, activity restrictions are necessary to allow the surgical wound and surrounding tissues to heal completely, usually lasting six to eight weeks. Patients must avoid strenuous activities, bending or twisting at the waist, and lifting anything heavier than a few pounds. Physical therapy may be recommended to help regain strength and function, particularly if the patient experienced significant preoperative weakness or gait issues.
The expected outcome of detethering surgery is often the stabilization of existing neurological symptoms and the prevention of further deterioration. Long-term follow-up is necessary because the formation of new scar tissue can lead to the spinal cord becoming tethered again, a condition known as retethering. Patients are advised to watch for a recurrence of symptoms, such as the return of back pain, leg weakness, or changes in bladder function, which would necessitate further evaluation.