Low back pain affects millions annually. In most cases, low back pain improves without surgery. However, severe back pain can be a symptom of a serious condition, one that is not well known and often misdiagnosed. Cauda equina syndrome (CES) occurs when the nerve roots of the cauda equina are compressed, disrupting motor and sensory function to the lower extremities and bladder. Often, patients with CES are admitted to hospitals as a medical emergency. This syndrome can lead to incontinence and even permanent paralysis.
Due to its resemblance to a horse's tail, the cauda equina is the collection of nerves at the end of the spinal cord equina. The spinal cord ends at the upper portion of the lower back, also known as the lumbar spine . The individual nerve roots located at the spinal cord’s end, which provide motor and sensory function to the legs and the bladder, continue in the spinal canal. The cauda equina is the continuation of these nerve roots in the spine’s lumbar region. These nerves send and receive messages to and from the pelvic organs and lower limbs.
INCIDENCE
CES is not related to race or gender. Although trauma-related CES can affect people of all ages, CES primarily affects adults. CES occurs in a very small percentage of patients who have undergone surgery for a lumbar herniated disc.
CAUSES
Most commonly, CES results from a massive herniated disc in the lumbar region. Herniated discs may be caused by a single injury or excessive strain. However, as an individual ages, disc material degenerates naturally, and the ligaments that hold disc material in place start weakening. As this degeneration progresses occurs, a relatively minor twisting movement or strain can cause a disc to rupture.
Other potential CES causes:
- Spinal tumors and lesions
- Spinal inflammation or infections
- Lumbar spinal stenosis
- Violent injuries lower back injuries (gunshots, auto incidents, falls)
- Birth abnormalities
- Spinal arteriovenous malformations (AVMs)
- Spinal hemorrhages (subarachnoid, subdural, epidural)
- Postoperative lumbar spine surgery complications
- Spinal anesthesia
SYMPTOMS AND DIAGNOSIS
CES symptoms mimic those found in other conditions. Its symptoms may vary in intensity, and they may evolve slowly over time. CES is accompanied by a range of symptoms. The severity of these depends on the degree of compression, along with the precise nerve roots that are being compressed. Apart from a herniated disc, other conditions with similar symptoms to CES include spinal cord compression, conus medullaris syndrome, peripheral nerve disorder, and irritation or compression of the nerves after exiting the spinal column as they travel through the pelvis (lumbosacral plexopathy).
Patients with back pain should be aware of these "red flag" symptoms, as they may indicate CES:
- Severe low back pain
- Sensory loss, motor weakness, or pain in one (more commonly both) legs
- Saddle anesthesia (inability to feel anything in the body areas that sit on a saddle)
- Recent onset of bladder dysfunction (e.g. incontinence or urinary retention)
- Recent onset of bowel incontinence
- Sensory abnormalities in the rectum or bladder
- Recent onset of sexual dysfunction
- Loss of reflexes in the extremities
Medical history implications:
- Recent violent injury in the back
- Recent surgery to the lumbar spine
- A history of cancer
- Recent severe infection
The following tests may be helpful in diagnosing CES:
- Magnetic resonance imaging (MRI): A diagnostic test, which produces three-dimensional images of body structures through computer technology and magnetic fields; produces images of nerve roots, the spinal cord, and surrounding areas.
- Myelogram: An X-ray of the spinal canal following the injection of a contrast material into the surrounding cerebrospinal fluid spaces; can show displacement on the spinal cord or spinal nerves due to bone spurs, herniated discs, tumors, etc.
TREATMENT
After a CES diagnosis and the establishment of the etiology, the treatment of choice is typically urgent surgery. The goal of which is to reverse neural dysfunction symptoms. Left untreated, CES can result in incontinence and even permanent paralysis .
Those experiencing any of the aforementioned “red flag” symptoms should consult a neurosurgeon as soon as possible. The best treatment for CES patients is prompt surgery. Treating patients within 48 hours after the onset of CES provides a significant advantage in improving sensory and motor deficits, along with rectal and urinary function. However, even patients who undergo surgery after the 48-hour ideal time frame may experience significant improvement.
Although short-term bladder function recovery may lag behind the reversal of lower extremity motor deficits, the function may continue to improve years after the surgery. Following surgery, drug therapy, accompanied with intermittent self-catheterization, can help lead patients to a slow but steady recovery of bowel and bladder function.
COPING WITH CES
CES can affect patients both emotionally and physically, particularly if it is chronic. People with CES may no longer be able to work. This may be due to either severe pain, motor weakness and sensory loss, socially unacceptable incontinence problems, or a combination of these problems.
Loss of bowel and bladder control can be extremely distressing, enacting a highly negative impact on social life, relationships, and work. CES patients may develop frequent urinary infections. Sexual dysfunction can also be devastating to the patient and his/her partner, and it may lead to depression and relationship difficulties.
Severe nerve-type (neurogenic) pain may require prescription pain medication, which can have side effects that may cause further issues. If pain is chronic, it may become "centralized" and radiate to other areas of the body. Neurogenic pain tends to worsen at night, possibly interfering with sleep. This type of pain tends to produce burning feelings, which can become constant and unbearable. Sensory loss may range from pins and needles to complete numbness, and it may affect the bowel, bladder and genital areas. Weakness is usually located in the legs, and it may contribute to issues with walking.
If possible, people with CES must receive emotional support from a network of family members and friends. It is important for patients to work closely with their physician on pain management and medication. There are several medications prescribed to address pain, bladder, and bowel problems. Additionally, some patients seek physical therapy and psychological counseling to help them cope with CES.
