Cauda Equina Syndrome; Causes, Symptom, Treatment

Cauda equina syndrome (CES) is a serious neurologic condition in which there is the acute loss of function of the lumbar plexus, neurologic elements (nerve roots) of the spinal canal below the termination (conus) of the spinal cord. It is a collection of symptoms and signs that result from severe compression of the descending lumbar and sacral nerve roots.

Up until recently, there has been little consensus in the literature as to how CES is defined. For example, Fraser et al. (2009) reported that were 17 different definitions of CES. However, this is improving and five characteristic features of CES are now more consistently recognized (Todd and Dickson, 2016).

These include

• Bilateral neurogenic sciatica – Pain associated with the back and/or unilateral/bilateral leg symptoms may be present.
• Reduced perineal sensation – Sensation loss in the perineum and saddle region is one of the most commonly reported symptoms.
• Altered bladder function leading to painless urinary retention – Bladder dysfunction is the other most commonly reported symptom and can range from increased urinary frequency, difficulty in micturition, change in the urine stream, urinary incontinence, and urinary retention.
• Loss of anal tone – loss or reduced anal tone may be evident if a patient reports bowel dysfunction. Bowel dysfunction may include fecal incontinence, inability to control bowel motions and/or inability to feel when the bowel is full with consequent overflow.
• Loss of sexual function – Sexual dysfunction is not widely mentioned in the literature but is an important aspect of health and wellbeing that needs discussion with patients, despite the potential embarrassment for both patient and therapist.

Anatomy of Cauda Equina Syndrome

Spinal cord

Conus medullaris

• tapered, the terminal end of the spinal cord
• terminates at T12 or L1 vertebral body

Filum terminal

• non-neural, fibrous extension of the conus medullaris that attaches to the coccyx

Cauda equina (horse’s tail)

• collection of L1-S5 peripheral nerves within the lumbar canal
• compression considered to cause lower motor neuron lesions

Bladder

Receives innervation from

• parasympathetic nervous system (pelvic splanchnic nerves and the inferior hypogastric plexus) and
• sympathetic plexus (hypogastric plexus)

• External sphincter of the bladder is controlled by the pudendal nerve
• Lower motor neuron lesions of cauda equina will interrupt the nerves forming the bladder reflex arcs

Types of Cauda Equina Syndrome

There are two main types of CES: CES-R and CES-I. R is for retention, where there is established retention of urine, and I is for incomplete, where there is reduced urinary sensation, loss of desire to void or a poor stream, but no established retention and overflow. Both need the immediate referral for urgent surgery, but CES-R is less likely to be reversible. In CES-I, the time window from onset of cauda equina symptoms to surgical decompression should be <48 hours (some say 24 hours) to have a reasonable chance of reversal.

Suspected CESS – Patients who do not have CES symptoms but who may go on to develop CES. It is important that patients understand the gravity of the condition and the importance of the time frame to seeking urgent medical attention. The use of a

Incomplete CES-I – Perianal/saddle paraesthesia but urinary retention/incontinence has not fully developed although the loss of urgency or decreased sensation may be present. Patients who present with urinary difficulties with a neurogenic origin, including loss of desire to void, poor stream, needing to strain to empty their bladder, and loss of urinary sensation.

Cauda equina syndrome with retention CES-R – Perianal/saddle paraesthesia with urinary retention or incontinence.

Retention CESR  – Patients who present with painless urinary retention and overflow incontinence; the bladder is no longer under executive control. An urgent surgical opinion is necessary

Complete CESC – Patients who have objective loss of the cauda equina function, absent perineal sensation, a loose anus and paralyzed bladder and bowel.

Causes of Cauda Equina Syndrome

• Spinal lesions and tumors
• Spinal infections or inflammation
• Lumbar spinal stenosis
• Violent injuries to the lower back (gunshots, falls, auto accidents)
• Birth abnormalities
• Spinal arteriovenous malformations (AVMs)
• Spinal hemorrhages (subarachnoid, subdural, epidural)
• Postoperative lumbar spine surgery complications
• Spinal anesthesia

Degenerative

• lumbar disc herniation (most common, especially at L4/5 and L5/S1)
• lumbar spinal canal stenosis
• spondylolisthesis
• Tarlov cysts
• facet joint cysts

Trauma

• Traumatic events leading to fracture or partial dislocation (subluxation) of the low back (lumbar spine) result in compression of the cauda equina.
• Spinal fracture or dislocation
• Epidural hematoma (may also be spontaneous, post-operative, post-procedural or post-manipulation)
• A collection of blood surrounding the nerves following trauma (epidural hematoma) in the low back area can lead to compression of the cauda equina.
• Penetrating trauma (gunshot or stab wounds) can cause damage or compression of the cauda equina.
• A rare complication of spinal manipulation is partial dislocation (subluxation) of the low back (lumbar spine) that can cause cauda equina syndrome.

Herniated Disk

• Most disk herniations will improve on their own (are self-limiting) and respond well to conservative treatment, including anti-inflammatory medications, physical therapy, and short periods of rest (one to two days).
• Cauda equina syndrome can result from a herniated lumbar disk.
• Of lumbar disk herniations, most occur either at the vertebral levels L4-L5 or L5-S1.
• Seventy percent of cases of herniated disks leading to cauda equina syndrome occur in people with a history of chronic low back pain, and some develop cauda equina syndrome as the first symptom of lumbar disk herniation.
• Males in their 30s and 40s are most prone to cauda equina syndrome caused by disk herniation.
• Most cases of cauda equina syndrome caused by disk herniation involve large particles of disk material that have completely separated from the normal disk and compress the nerves (extruded disk herniations). In most cases, the disk material takes up at least one-third of the canal diameter.

Spinal Stenosis

• Spinal stenosis is any narrowing of the normal front to back distance (diameter) of the spinal canal.
• Narrowing of the spinal canal can be caused by a developmental abnormality or degenerative process.
• The abnormal forward slip of one vertebral body on another is called spondylolisthesis. Severe cases can cause a narrowing of the spinal canal and lead to cauda equina syndrome

Tumors (Neoplasms)

• Cauda equina syndrome can be caused by isolated tumors (primary neoplasms) or from tumors that have spread to the spine from other parts of the body (metastatic spinal neoplasms). Metastatic spine tumors are most commonly from the prostate or lung in males and from the lung and breast in females.
• Malignant – lymphoma, metastases, primary CNS malignancies (e.g. ependymoma, schwannoma, neurofibroma)
• The most common initial symptom of people with cauda equina syndrome caused by a tumor (spinal neoplasm) is severe low back and leg pain.
• Later findings include lower extremity weakness.
• Loss of feeling in the legs (sensory loss) and loss of bowel or bladder control (sphincter dysfunction) are also common.

Inflammatory Conditions

• Both acute and chronic form may be seen in long-standing ankylosing spondylitis (2nd-5th decades; average 35 years)
• Long-lasting inflammatory conditions of the spine, including Paget’s disease and ankylosing spondylitis, can cause a narrowing of the spinal canal and lead to cauda equina syndrome.

Infectious Conditions

• Infections in the spinal canal (spinal epidural abscess) can cause deformity of the nerve roots and spinal column.
• Symptoms generally include severe back pain and rapidly worsening muscle weakness.
• Infective – epidural abscess , tuberculosis (Pott disease)

Accidental Medical Causes (Iatrogenic Causes)

• Poorly positioned screws placed in the spine can compress and injure nerves and cause cauda equina syndrome.
• Continuous spinal anesthesia has been linked to cases of cauda equina syndrome.
• Lumbar puncture (spinal tap) can cause a collection of blood in the spinal canal (spontaneous spinal epidural hematoma) in patients receiving medication to thin the blood (anticoagulation therapy). This collection of blood can compress the nerves and cause cauda equina syndrome.
• Aortic dissection
• Arteriovenous malformation

Symptoms of Cauda Equina Syndrome

Basic symptoms are

• Bilateral neurogenic sciatica – Pain associated with the back and/ or unilateral/bilateral leg symptoms may be present.
• Reduced perineal sensation – Sensation loss in the perineum and saddle region is the most commonly reported symptom.
• Altered bladder function leading to painless retention – Bladder dysfunction is the most commonly reported symptom and can range from increased frequency, difficulty in micturition, change in the stream, incontinence and retention.
• Loss of anal tone – loss or reduced anal tone may be evident if a patient reports bowel dysfunction. Bowel dysfunction may include incontinence, inability to control motions, inability to feel when the bowel is full and consequently overflow.
• Loss of sexual function – Sexual dysfunction is not widely mentioned in the literature but is an important aspect that should be discussed with patients.
• Weakness in the Legs – The weakness is often times asymmetric.
• Loss of Sensation – Those affected may experience numbness or tingling in their perineum
• Loss of Reflexes – A person’s knee and ankle reflexes might be diminished, along with anal and bulbocavernosus abilities.
• Sensory Loss – Sensory loss may range from, ‘pins and needles,‘ to complete numbness. It might affect the person’s bowel, bladder and genitalia Bladder, Bowel and

Associate clinical feature is-

• Severe back pain
• Saddle anesthesia i.e., anesthesia or paraesthesia involving S3 to S5 dermatomes, including the perineum, external genitalia, and anus; or more descriptively, numbness or “pins-and-needles” sensations of the groin and inner thighs which would contact a saddle when riding a horse.
• Bladder and bowel dysfunction, caused by the decreased tone of the urinary and anal sphincters.
• Detrusor weaknesses causing urinary retention and post-void residual incontinence as assessed by bladder scanning the patient after the patient has urinated.
• Sciatica type pain on one side or both sides, although pain may be wholly absent
• The weakness of the muscles of the lower legs (often paraplegia)
• Pain in one leg (unilateral) or both legs (bilateral) that starts in the buttocks and travels down the back of the thighs and legs (sciatica)
• Numbness in the groin or area of contact if sitting on a saddle (perineal or saddle paresthesia)
• Bowel and bladder disturbances
• Lower extremity muscle weakness and loss of sensations
• Inability to urinate (urinary retention)
• Difficulty initiating urination (urinary hesitancy)
• The decreased sensation when urinating (decreased urethral sensation)
• Inability to stop or control urination (incontinence)
• Reduced or absent lower extremity reflexes
• Local pain is generally a deep, aching pain resulting from soft tissue and vertebral body irritation.
• Leg pain (radicular pain) is generally a sharp, stabbing pain resulting from compression of the nerve roots.
• Radicular pain projects along the specific areas controlled by the compressed nerve (known as a dermatomal distribution).
• Inability to stop or feel a bowel movement (incontinence)
• Constipation
• Loss of anal tone and sensation
• Achilles (ankle) reflex absent on both sides.
• Sexual dysfunction
• Absent anal reflex and bulbocavernosus reflex
• Gait disturbance

Red flag symptoms of cauda equina syndrome (CES): typically from a central PID
Usually severe LBP and bilateral neurogenic sciatica
Perineal/genital numbness
Inability to pass water since >6–8 h
Triage
CES: Incomplete—Emergency management!	CES-Retention: Urgent management!
Ideally surgery within 24 h of onset—good prognosis	Ideally surgery within 24 h of diagnosis: less good prognosis
Symptoms	Symptoms
Sciatica may be unilateral, bilateral or absent (L5/S1prolapse)—if present, is it increasing in intensity or becoming bilateral?	Sciatica: as for CES-I—NB Lumbar and sacral nerve roots may suffer progressive damage resulting in long-term neuropathic leg pain/numbness
Perineal numbness: may be unilateral and patchy, becoming bilateral and spreading	Perineal numbness: as for CES-I but likely to be widespread and complete with diminishing discomfort
Neurogenic urinary dysfunction: HNPU>6 h loss of desire to void, poor stream, strain to micturate, the sensation of full bladder	Neurogenic urinary dysfunction: HNPU >8 h painless urinary retention, overflow incontinence, no bladder sensation or control, fecal incontinence
Physical signs	Physical signs
Sciatica: check for the neurological deficit in legs—SLR, reflexes, power, and sensation. Maybe deteriorating and becoming bilateral	Sciatica: as for CES-I. Maybe more severe and bilateral with the increased neurological deficit. May be absent or mild with sequestrated L5/S1 prolapse
Perineal numbness: usually incomplete—check light touch and pin-prick—always test for both	Perineal numbness: the complete sensory deficit. Check light touch and pin-prick
Neurogenic bladder and bowel dysfunction: check anal sphincter tone (Deletion) and ‘wink’ reflex. Test trigone sensation—pull catheter gently	Neurogenic bladder and bowel dysfunction: painless full bladder, no anal sphincter function. No trigone sensation on pulling the catheter

Diagnosis of Cauda Equina Syndrome

A doctor can diagnose cauda equina syndrome. Here’s what you may need to confirm a diagnosis

• A medical history – in which you answer questions about your health, symptoms, and activity.
• A physical exam to assess your strength – reflexes, sensation, stability, alignment, and motion. You may also need blood tests.
• Magnetic resonance imaging (MRI) scan – which uses magnetic fields and computers to produce three-dimensional images of your spine.
• A myelogram – an X-ray of the spinal canal after injection of contrast material — which can pinpoint pressure on the spinal cord or nerves.

• A computed tomography (CT) scan.
• Urodynamic studies – may be required to monitor recovery of bladder function following decompression surgery.

Treatment of Cauda Equina Syndrome

Non-surgical 

Rest – It is important that patient take proper rest and sleep and avoid any activities which will further aggravate the disc bulge and its symptoms. Many minor disc bulges can heal on their own with rest and other conservative treatment.

Ice & Moist Heat Application – Ice application where the ice is wrapped in a towel or an ice pack for about 20 minutes to the affected region, thrice a day, helps in relieving the symptoms of a disc bulge. Heat application in the later stages of treatment also provides the same benefit.

Cervical Pillow – It is important to use the right pillow to give your neck the right type of support for healing from a cervical disc bulge and also to improve the quality of sleep.

Hot Bath – Taking a hot bath or shower also helps in dulling the pain from a disc bulge. Epsom salts or essential oils can be added to a hot bath. They will help in soothing the inflamed region.

Over the Door Traction – This is a very effective treatment for a disc bulge. It helps in relieving muscle spasms and pain. Typically a 5 to 10-pound weight is used and it is important that patient do this under medical guidance.

• Patient education on proper body mechanics (to help decrease the chance of worsening pain or damage to the disk)
• Physical therapy, which may include ultrasound, massage, conditioning, and exercise
• Weight control
• Use of a lumbosacral back support

Medications

• Analgesics – Prescription-strength drugs that relieve pain but not inflammation.
• Antidepressants: A Drugs that block pain messages from your brain and boost the effects of endorphins (your body’s natural painkillers).
• Medication – Common pain remedies such as aspirin, acetaminophen(Tylenol), ibuprofen (Advil, Motrin), and naproxen can offer short-term relief. All are available in low doses without a prescription. Other medications, including muscle relaxants and anti-seizure medications, treat aspects of spinal stenoses, such as muscle spasms and damaged nerves.
• Corticosteroid injections – Your doctor will inject a steroid such as prednisone into your back or neck. Steroids make inflammation go down. However, because of side effects, they are used sparingly.
• Anesthetics – Used with precision, an injection of a “nerve block” can stop the pain for a time.
• Muscle Relaxants – These medications provide relief from spinal muscle spasms.
• Neuropathic Agents: Drugs(pregabalin & gabapentin) that address neuropathic—or nerve-related—pain. This includes burning, numbness, and tingling.
• Antibiotic –  to the management of bowel & bladders control and protect further infection. Infection causes should be treated with appropriate antibiotic therapy
• Topical Medications – These prescription-strength creams, gels, ointments, patches, and sprays help relieve pain and inflammation through the skin.
• Calcium & vitamin D3 – to improve bones health and healing fracture.
• Glucosamine & diacerine – can be used to tightening the loose tension and regenerate cartilage or inhabit the further degeneration of cartilage.
• Corticosteroid – to healing the nerve inflammation and clotted blood in the joints.
• Dietary supplement -to remove the general weakness & improved the health.
• Lesion debulking –  is required for space-occupying lesions – eg, tumors, abscess.
• If surgery cannot be performed – radiotherapy may relieve cord compression caused by malignant disease.
• Radiation therapy and Chemotherapy – may have a role in treatment if the cauda equina syndrome is caused by the tumor.
• Support or brace – A pelvic belt can be used to stabilize a joint that is too loose until the inflammation and pain subside.
• Joint injections – Numbing injections into the sacroiliac joint are used diagnostically to help identify the cause of them but are also useful in providing immediate pain relief. Typically, an anesthetic is injected along with an anti-inflammatory medication.

Other treatment options

• Other treatment options –  may be useful in certain patients, depending on the underlying cause of the CES
  • Anti-inflammatory agents, including steroids, can be effective in patients with inflammatory causes – eg, ankylosing spondylitis.
  • Patients with spinal neoplasms should be evaluated for chemotherapy and radiation therapy.

• Weakness – Physiotherapy may be helpful if there is no inflammatory component such as that found in arachnoiditis where exercise might exacerbate the condition and cause flare-ups.
• Sensory Loss – Little conventional treatment exists for sensory loss in Cauda Equina syndrome, although in conditions such as Multiple Sclerosis use of vitamin B complex is considered to have potential beneficial effects.
• Sore Feet – Loss of muscle tone and control over the movement of the foot may lead to foot pain. If foot drop is a notable issue, a brace to hold it in position may help. It is important; however, to attempt to maintain as much muscle tone as possible as well as the range of movement (ROM). Exercises might help.
• Sexual Dysfunction – Sexual dysfunction is very hard for people to talk about at times. It might be best to pursue advice from specialists. If no physical treatment is feasible for improving function, the person and their sexual partner might pursue counseling which might help to lessen the impact of this disability on not only the person affected but their partner.
• Depression – Depression is an understandable reaction to a form of debilitating illness. Antidepressant medication should be reserved for severe depression. Counseling and support are the preferred methods of managing depression. Sharing experiences may help people with Cauda equina syndrome to come to terms with the disabilities associated with Cauda Equina syndrome.
• Poor Circulation – Poor circulation is a common issue in Cauda Equina syndrome. The person’s feet may be cold and turn white, then red when re-warmed (also known as, ‘Raynaud’s syndrome,) as well as chilblains. Some medications exist that can be taken, yet it is most likely best to use general measures such as avoiding getting cold feet and foot massage with warm oil to help improve the person’s circulation. Avoid extremely hot baths after the feet have been cold because it will most likely cause chilblains.

• Postoperative care – includes addressing lifestyle issues (eg, obesity), and also physiotherapy and occupational therapy, depending on residual lower limb dysfunction.

If you have loss of bladder or bowel function, the following tips may help

• Use a catheter to completely empty your bladder three or four times a day.
• Drink plenty of fluids and use good personal hygiene to prevent urinary tract infections.
• Check for waste and clear the bowels with gloved hands. If needed, use glycerin suppositories or enemas.
• Wear protective pads and pants to prevent leaks.

The surgical options include

• Laminectomy – An operation on the spine to remove some of the bone and ligament that surround the spinal cord, in order to free up space around the nerves.
• Microdiscectomy – An operation where a smaller portion of bone and ligament is removed and the surgeon will gently move the nerves out of the way to find a slipped disc and try to remove as much of the disc as is possible.

Physical therapy

Physical therapists can assist in sitting stability and transferring by working on strength training. Therapists will work on balance, gait, and transfers since muscle weakness or paralysis may occur in the lower extremities (Dawodu, 2013). Additionally, electrical stimulation is also helpful to enhance muscle tone (Dawodu, 2013).

Incorporating Aerobic Exercise

Aerobic exercises, such as walking, biking, and swimming are often recommended for CES patients. These types of exercises not only help to strengthen muscles and improve balance but are also effective in improving the functioning of the circulatory system. For best results, patients should walk, bike, swim, jog or hike for at least 30 minutes a day, five days per week. Individuals who are very weak or out of shape should start with five to 15 minutes per day and increase their time slowly to ensure optimal results.

Incorporating Strengthening Exercise

Resistance-training exercises, including hamstring curls, leg extensions, and calf raises can also help to increase strength and endurance. Cauda equina syndrome patients should perform two to three sets of 10 to 15 repetitions of these exercises once or twice per week. Space these resistance-training sessions out during the week to allow the muscles adequate amounts of recovery time.

Keywords: Cauda equina syndrome, Central disc prolapse, Bilateral sciatica, Urinary retention, Perineal hypoaesthesia, Sexual, dysfunction Intervertebral disc displacement, Neurogenic urinary bladder

References