Cruralgia or neuralgia crurale is a pain that follows the path of the crural nerve (now called the femoral nerve).
This nerve is born at the bottom of the spine (or spine) of the meeting of nerve roots emanating from the spinal cord, or spinal cord according to the new nomenclature. This cord is a cord about 50 cm long extending the brain and sheltered inside the spine that protects it thanks to the bones of the vertebrae.
A total of 31 pairs of nerves emerge to the right and left of the spinal canal: from top to bottom, 8 at the neck (cervical roots), 12 at the upper back (thoracic roots), 5 at the lower back ( lumbar roots), 5 at the level of the sacrum and 1 at the level of the coccyx.
The crural nerve is, like all the spinal nerves, a nerve that is both sensory and motor: it innervates the front of the thigh and the leg and allows the flexion of the thigh on the trunk, the extension of the knee and the collection of sensory information from this region (hot, cold, pain, contact, pressure, etc.)
Why do we have cruralgia?
In the vast majority of cases, cruralgia is due to compression of the crural nerve by a herniated disc. The hernia is a formation coming from an intervertebral disk, which, coming out of its normal space, puts pressure on one of the roots of the crural nerve.
The vertebral column is formed by the stacking of vertebrae separated from each other by an intervertebral disk, a structure similar to that of the cartilage and the ligament. This disc normally acts as a shock absorber and force distributor. This disc, which includes a ring with a nucleus at its center, tends to dehydrate and crack over time. The disk core can then migrate to the periphery and protrude, and this is the disc herniation. This hernia can then irritate and compress a nerve root, in this case the lumbar root L3 or L4 for the crural nerve, and cause pain. This compression can also be related to spinal osteoarthritis (parrot beaks,
Much more rarely, other causes of compression can be considered (infection, hematoma, fracture, tumor, etc.).
What are the symptoms of cruralgia?
In its usual form, related to a herniated disc, the beginning is usually brutal, characterized by lumbar pain (low back pain) that descends into the buttock, bypasses the hip to pass in front of the thigh and down into the calf.
This pain can be accompanied by other sensations such as tingling or tingling, typical of neuralgia. There may also be areas of lesser sensation (hypoesthesia). A motor deficit can also cause difficulty lifting the thigh or raising the foot.
When to consult
In general, the question does not arise and the person consulted quickly, because the pain is disabling and needs to be quickly relieved. Nevertheless, in some cases, the pain is not in the foreground or the signs are more atypical: progressive onset, association with a fever, etc. which requires a balance in search of another cause than the disc herniation.
Some herniated discs require urgent care. Fortunately, they are relatively rare. These hernias where it is necessary to consult in urgency are those where there exists:
– A very strong pain which require a powerful antalgic treatment,
– A paralysis (major motor deficit)
– Urinary disorders (loss of urine, difficulty to urinate)
– Des digestive disorders (sudden constipation)
– Sensory disturbances (anesthesia of the perineum, area between the front of the thighs and the anus)
If any of these signs occur during cruralgia, this is a surgical emergency. Indeed, without treatment, nerve compression can lead to irreversible neurological damage (urinary disorders, paralysis, anesthesia …). The treatment aims to relieve the nerves and prevent it from being permanently compressed and damaged.
In case these signs appear, it is necessary to consult quickly.
Which doctor to consult in case of cruralgia?
Most of the time, the general practitioner is able to diagnose and treat cruralgia.
Specialists in this disease include rheumatologists, neurologists and rehabilitators (PRMs). Some radiologists may also perform a therapeutic procedure.
Surgical emergencies are managed by neurosurgeons or orthopedic surgeons.
Some cases of painful crural pain may require consultation in a pain center.
What exams do we do?
In classical cruralgia, the symptoms are so typical that the clinical examination is sufficient. Tensioning of the nerve by a maneuver intended to find a sign of inverted Lasègue or Leri’s sign (on the stomach, extension behind the leg) causes an increase in pain. A small motor deficit and a decrease in the sensitivity corresponding to the territory of the crural nerve can also contribute to confirm the diagnosis. When the L3 lumbar root is squeezed, the sore path concerns the buttocks, the anterior aspect of the thigh and the inner side of the knee, and the muscular insufficiency affects the quadriceps and the anterior tibial muscle of the leg (flexion of the foot). When the L4 root is compressed,
Increased pain with coughing, sneezing, or defecation are classic signs of pain due to compression of a nerve root. In principle, the pain subsides at rest, but there may be nocturnal recrudescence.
The other examinations are made only in case of doubt about the origin of cruralgia or inefficacy of the treatment, or even aggravation: x-rays of the spine, blood test, CT scan, MRI. However, in Western countries, these examinations are often practiced more or less systematically. They then make it possible to visualize the compression of the nerve roots. Other explorations may, more rarely, be necessary such as an electromyogram, for example.
The treatments of cruralgia
In case of cruralgia related to a herniated disc, the treatment initially includes the resting, analgesics, anti-inflammatories administered in sufficient doses and long enough sometimes associated with muscle relaxants. Medical treatment usually lasts 6 to 8 weeks. Many failures and recurrences are in this respect due to a therapeutic insufficiency.
Sometimes one or more local corticosteroid injections (epidural infiltrations) are needed to relieve pain and inflammation. The analgesic treatment must also be adapted to the level of the pain, with, if necessary, derivatives of the morphine.
In some cases, surgery may be necessary.
Once the acute crisis has passed, physiotherapy is also very useful, especially by learning the movements of the back, by weight training (abdominal, spinal and quadriceps). In overweight people, weight loss can reduce the stress on the vertebrae. In some cases of trailing or recurring cruralgia, the pain can evoke a nerve pain causing so-called neuropathic pain which then require a specific treatment not using the usual analgesics, but other drugs such as anti-inflammatory drugs. epileptics and / or low-dose antidepressants also having the property of reducing this type of pain.
Anyway, the regular practice of a sporting activity, the maintenance of a correct musculature, the management of the movements, are strongly advised in the course of a cruralgie, like a sciatica, in order to avoid recurrences.
Finally, some herniated discs, which can cause a cruralgia, can be of professional origin in connection with heavy loads or exposure to vibrations, prolonged sitting. It is then the occupational doctor who is important to contact for possible professional care.