L5 syndrome

What is L5 Syndrome?

The L5 syndrome describes a pain syndrome that occurs due to nerve irritation in the fifth lumbar vertebra. The spinal cord runs within the spine, from which nerves emerge along the entire length of the spine in order to supply the individual areas of the body in a sensitive and motorized manner. Pinching nerves causes pain and other problems. So this is a root compression syndrome.

L5 is a very often affected segment that is located in the lower area of ​​the lumbar spine at the transition to the coccyx and supplies the area from the rear thigh to the big toe. The compression of the nerve root can lead to pain, paralysis and / or sensitivity disorders in the supply area of ​​the affected nerves. Depending on the cause of the nerve irritation, many different accompanying symptoms, abnormalities and therapies can result from L5 syndrome.

Also read on this topic: Lumbar spine pain

Treatment of L5 Syndrome

The treatment can vary widely and must be made dependent on the cause of the L5 syndrome. Too often, a herniated disc is treated surgically, although physiotherapeutic and conservative therapies are just as successful. Surgery can sometimes achieve success much faster, but in the long term the results are on par with those of conservative treatment, which involves fewer risks.

In some cases, however, surgery may be necessary during the course of treatment. In the case of a herniated disc, this is the case with acute damage to the nerve roots; in the case of tumors or spinal canal stenosis, surgery is often the only possible causal treatment. This also applies to sudden incontinence due to the damage.

In support of all causes of the L5 syndrome, adequate pain therapy should be provided to enable movement and prevent relieving postures. This can be done with mild pain relievers from the NSAID group, for example ibuprofen or diclofenac. Opioids such as morphine can also be used for severe pain.

Read more on this topic at: Treatment of lumbar spine syndrome

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My name is dr. Nicolas Gumpert. I am a specialist in orthopedics and the founder of .
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The spine is difficult to treat. On the one hand it is exposed to high mechanical loads, on the other hand it has great mobility.

The treatment of the spine (e.g. herniated disc, facet syndrome, foramen stenosis, etc.) therefore requires a lot of experience.
I focus on a wide variety of diseases of the spine.
The aim of any treatment is treatment without surgery.

Which therapy achieves the best results in the long term can only be determined after looking at all of the information (Examination, X-ray, ultrasound, MRI, etc.) be assessed.

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These drugs can help

In order to prevent pain-related relieving posture, pain reliever medication is prescribed. Depending on the severity of the pain, medicines like diclofenac, ibuprofen, or indomethacin may be effective. If the symptoms are particularly severe, pain-relieving, opioid drugs are prescribed. These include fentanyl, buprenorphine, hydromorphone, oxycodone, and tilidine.

Some pain relievers are at increased risk of developing addiction. The medication intake should be discussed with the attending physician or the family doctor and adjusted if necessary.

Read more on this topic at:

  • Diclofenac
  • Ibuprofen
  • Fentanyl
  • Opioids

These exercises can help

Targeted exercises of the back muscles can help alleviate the symptoms of a herniated disc with L5 syndrome. You should start with a low load and gradually increase. Exercises like arm rests with arm and leg raises, planks, abdominal muscle exercises like sit-ups and rowing can have a positive effect on posture.

Read more on this topic at: Exercises after a herniated disc of the lumbar spine

Periradicular Therapy (PRT)

Periradicular therapy is a treatment of pain. As the Latin name suggests, this involves a small operation directly on the nerve root, whereby certain medications can be applied CT-controlled directly to the cause of the pain. Usually a mixture of pain reliever and anti-inflammatory drugs is injected to allow the tissues to heal. This is often an anesthetic and cortisone, which also stops an inflammatory reaction.

PRT can be an important treatment for severe and especially chronic pain, but it should not be a permanent solution. The pain is suppressed for a few days before a new treatment is necessary. This can give the body the time to break down the herniated disc itself. In the case of long-term complaints, however, physiotherapeutic measures should be in the foreground.

Read more on this topic at: Therapy of a herniated disc of the lumbar spine

When do you need an operation?

An operation is necessary in L5 syndrome when the spinal canal is narrowed, for example due to degenerative protrusions. Herniated discs are rarely operated on. However, if the person concerned suffers from a herniated disc with pronounced motor deficits, i.e. paralysis of the leg, an operation is usually performed immediately.

Read more on this topic at: Operation of a herniated disc in the lumbar spine

Duration / forecast

The duration of the L5 syndrome can vary widely and depends largely on the severity of the disease, the response to therapy and the patient's own wishes. The sooner the syndrome is recognized, the better the course. A herniated disc is often successfully treated conservatively and leads to relief or even full recovery over the course of weeks to months.

There may be only minor pain that subsides after a few days. A severe finding can, however, also cause lasting discomfort and also cause long-term damage. Back pain in the lumbar region has a high potential to cause discomfort over a long period of time.

Important factors that favor chronic pain for more than 6 months are:

  • Lack of muscles and exercise
  • incorrect postures
  • Obesity
  • frequent, heavy lifting.

The underlying disease can often be remedied conservatively or surgically in a short time, but back pain can persist beyond that.

Read more on this topic at: Duration of a lumbar spine syndrome

If the neuroforamen is narrow, surgery is needed to correct the symptoms. Those affected often benefit from the operation. If the pain becomes chronic, it has a negative impact on the prognosis. Therefore, pain relieving medication is indicated to prevent a relieving posture due to pain and chronic pain.


The most common cause of L5 syndrome is a herniated disc. The intervertebral disc is located between two vertebral bodies to cushion their impact. It consists of an outer ring and a jelly-like mass inside. In a herniated disc, certain movements and long-term changes in the structure of the intervertebral disc cause the outer ring to tear, which allows the inside to escape and thus press on surrounding nerves and cause pain syndrome.

Read about this too: General symptoms of a herniated disc

Less often, however, the pressure on the nerve root on the spinal cord can also be attributed to a tumor. Both benign and malignant tumors can grow in the spinal canal and damage important structures. In addition to tumors that consist of solid tissues, fluid-filled cysts or other accumulations of fluid are also conceivable in this area. Tumors or swellings of surrounding organs in the abdominal and pelvic area can in principle also cause a pain syndrome in the spine.

In addition to foreign tissues, the spine itself can grow and put increasing pressure on the nerves. If the spinal cord and the nerve roots in the vertebral canal are narrowed by the vertebral bodies or foreign tissues, one speaks of a so-called "spinal canal stenosis".

More rarely, however, the cause of the pain syndrome is not directly in the lumbar spine, but rather earlier in the vascular system.This can lead to vascular constrictions and insufficient supply of the nerves and the spinal cord, which is noticeable with symptoms similar to mechanical nerve irritation.

Read more on this topic at: Causes of a lumbar spine syndrome

disc prolapse

A herniated disc is the most common cause of L5 syndrome. A herniated disc in the area of ​​the fifth lumbar vertebra and the first sacral vertebra can damage the L5 nerve root that emerges from the spinal canal between these vertebrae. In this area, most people suffer signs of wear and tear of the intervertebral disc over the years as a result of a combination of low muscle activity and movement and frequent, incorrect loading, for example when lifting heavy loads from the back. It can easily happen that the gelatinous core of the ban disc bulges out of the surrounding fibrous ring and constricts the spinal canal and nerves.

Sensitivity disorders can occur in the area of ​​the inner and rear thighs, the outer rear lower leg, the back of the foot and the outer edge of the foot. In addition to the weakness of the toe muscles, a weakness when rolling the foot is often noticeable. Urinary and intestinal continence may rarely function properly, depending on the exact location of the herniated disc.

Read more on this topic at:

  • Herniated disc L4 / L5
  • L4 syndrome
  • Herniated disc in the lumbar spine

Narrow in the neuroforamen

A neuroforamen is an opening in a vertebral body. Each vertebral body has a neuroforamen on the left and right, which is used for the exit of the nerves from the spinal cord. The neuroforamina form a kind of bony canal along the spine. The neuroforamen can become narrowed and put pressure on the nerves that run through them. A tightness in the neuroforamen can be congenital or result from wear and tear. It is a possible cause for the development of an L5 syndrome.

You can recognize L5 syndrome by these symptoms

Symptoms characteristic of L5 syndrome arise depending on the extent of the nerve damage. People typically experience pain in the dermatome of the L5 nerve root. There is pain in the back of the thigh, the side knee and the front and outer side of the lower leg. The pain extends over the back of the foot to the big toes. Those affected can feel the pain at rest or during exercise.

The affected parts of the body can also have sensitive disorders such as numbness, tingling, pulling and pins and needles. If, in addition to the sensitive nerve fibers, motor nerve fibers are affected, muscle paralysis also occurs. The sick then suffer from limited mobility in the hip joint and can only move the leg with difficulty.

Typical is a dorsiflexion weakness in which the affected person can neither lift the foot nor the big toe. The heel stand is severely disabled and not feasible. Local pain in the spine is also an important symptom. This can express itself in a pressing and piercing manner. In addition to the circumstances accompanying the herniated disc, swelling, overheating and other signs of inflammation can occur at this point.

What you might also be interested in on this topic:

  • Lumbar spine pain
  • Signs of a herniated disc
  • Symptoms of lumbar spine syndrome

Pain in the leg

Pain in the affected leg is a major symptom of L5 syndrome. Often there is pain in the back of the thigh, the side knee and the front and side lower leg, the back of the foot and the big toe. If a tumor or a cyst presses on the nerve root, the pain is often calm, i.e. permanent. In the case of a herniated disc, the pain often occurs during exercise.

Read more on this topic at: Herniated Disc: Symptoms in the Leg

Tingling sensation / numbness

In addition to pain, sensory disorders often occur in the affected supply areas of the L5 nerve root. These include tingling, pins and needles, and numbness. The symptoms can be temporary or permanent.

Paralysis (paresis)

A paresis describes a paralysis of the muscles due to a disruption of the responsible nerves. Nerve cells can only recover after an irritation over a certain period of time. They perish quickly if they are under pressure, damaged or circulatory disorders and cannot be replaced. In the following weeks the muscles break down and become weaker.

If the paresis persists beyond that, the muscle can change irreversibly, so that it can no longer fulfill any motor function and one can achieve little or no movement through the muscle. In L5 syndrome, several muscles of the leg can be affected by the paresis. Since there is often a supply from several different nerves, the failure can be partially compensated for by other muscle cords. The greatest motor damage in L5 syndrome typically occurs on the toe muscle.

Peroneal palsy

Peroneal palsy is a disorder of the Common peroneal nerve. The consequences are sensory disturbances on the lateral lower leg and back of the foot and the paralysis of certain muscles that are supplied by the nerve. The consequence is that those affected cannot move the foot and toe lifters. There is a typical gait pattern, the so-called stepper gait. This is caused by the fact that the foot has to be raised higher when walking and the toes point to the ground when pulling the leg due to gravity.

Peroneal palsy is an important differential diagnosis of L5 syndrome and should be ruled out. The dorsiflexor weakness is the typical deficiency symptom, which immediately indicates damage to the nerve root at level L5. Two other small muscles can also lift the foot, but if the L5 fails completely, a significant weakness can be felt.

Trendelenburg sign

The Trendelenburg sign describes another motor failure symptom that can occur when the L5 nerve root is damaged. The affected nerve also arises from this segment and supplies individual small gluteal muscles. If this nerve fails completely, the pelvis will sink to the opposite side, as the muscles can no longer hold the pelvic ring upright. While running, this is noticeable as a kind of waddling, which is known as the Trendelenburg sign.

no pain

The L5 syndrome describes a pain in the spine caused by various underlying diseases. The herniated disc, the most common cause of the pain syndrome, can also be silent and cause no discomfort. This leads to a tear in the ring of the intervertebral disc, but no nerve root is compressed and no local complaints are caused because the emerging mass emerges at a different point. The herniated disc is often discovered later as an incidental finding. The pain can sometimes only appear after many years and thus reveal an old, unnoticed herniated disc.

Other constrictions in the vertebrae, for example a tumor or spinal canal stenosis, can initially be pain-free. The changes in the spine often only become noticeable suddenly when nerves or the spinal cord are affected.


The L5 syndrome does not describe a disease of its own but a symptom. L5 syndrome can therefore be diagnosed by the attending physician with a detailed discussion about the symptoms and previous illnesses as well as a physical and neurological examination with a focus on sensitivity, paralysis and reflexes.

However, the cause of the pain syndrome often requires further diagnostic investigations. In order to be able to diagnose a herniated disc, a radiological examination with CT or MRI is often necessary. Other masses in the area of ​​the spinal cord, for example cysts, tumors or spinal canal stenoses, can also be identified in this way.

In rare cases, for example with unclear tumors, a biopsy is also necessary. This is an invasive diagnostic measure. In order to be able to diagnose possible damage to the nerves or muscles, so-called "electromyography" can be performed. The function of the nerve in the muscle can be examined more closely.

What you might also be interested in on this topic: MRI of the lumbar spine

Lasègue sign

The so-called "Lasègue sign" describes a test that can be used to diagnose a herniated disc or other neurological diseases. A motor maneuver is used to test whether the nerve roots in the lumbar spine area are irritated and inflammatory changes.

To do this, the person concerned lies flat on their back and slowly lifts the extended leg. As a rule, flexion of up to 90 ° in the hip joint should be possible without any problems. If pain occurs early on during this exercise, this suggests an inflammatory process in the nerve root such as a herniated disc.

Right or left?

In the case of a herniated disc, neurological failure symptoms are often only observed when the herniation is leaning in one direction. The nerves of each individual segment emerge laterally from the spinal cord and the spinal canal, where they can be depressed and irritated by a herniated disc. In this case, the complaints that are passed on occur on the respective affected side. Symmetrical complaints, on the other hand, are unlikely, since both nerve roots are rarely equally involved. In this case, other neurological diseases must be included in the diagnosis.

Identification muscle

A characteristic muscle is a specific muscle that can be clearly assigned to a vertebral segment. The nerve in this vertebral segment is therefore primarily responsible for the motor function of this one muscle. In emergency medicine, the identification muscles play an important role in quickly localizing potential nerve damage.

For the L5 segment, the key muscle is the so-called "extensor hallucis longus" muscle. This muscle can stretch in the ankle joint as well as in the big toe joint and thus lift the foot and big toe skyward. Other muscles, for example the knee extensors, can also be affected in an L5 syndrome, but are usually supplied by other nerves, which is why there is no complete failure.

Muscle failure is another indication of L5 syndrome.