The lumbar spine, or lumbosacral spine, refers to the part of the spine located in the lower back, just above the sacrum. Very mobile zone and supporting all the rest of the spine, it is heavily used on a daily basis and sometimes the victim of premature aging. Also, the lumbar spine is often the site of pain, the causes of which can be numerous.

The term spine refers to the spine. It is made up of a stack of different vertebrae: 7 cervical vertebrae, 12 dorsal (or thoracic) vertebrae, 5 lumbar vertebrae, the sacrum made up of 5 fused vertebrae and finally the coccyx made up of 4 vertebrae.

The lumbar spine refers to the low, mobile part of the spine, located just above the sacrum. It is made up of five lumbar vertebrae: the L1, L2, L3, L4 and L5 vertebrae.

These five vertebrae are connected and articulated at the rear by the facet joints, and at the front by the vertebral discs. Between each vertebra, nerve roots come out through holes called foramina.

The lumbar spine presents a concave arch towards the rear, called lumbar lordosis.

Like the rest of the spine, the lumbar spine protects the spinal cord up to the L1-L2 vertebrae, then the spinal nerves from the L1-L2.

Dynamically, due to its location, the lumbar spine supports the rest of the spine and ensures its mobility. It also plays the role of shock absorber and load distribution between the pelvis and the thorax. The erector muscles of the spine, also called the spinal muscles, which extend on both sides of the spine help to relieve some of this pressure exerted on the spine.

Due to its anatomical complexity, the neurological structures it contains, the daily mechanical constraints that it supports but also the physiological aging of its various structures, the lumbar spine can be affected by many pathologies. Here are the main ones.

Low back pain

Low back pain is the umbrella term for lower back pain. In its latest recommendations on the management of low back pain, the HAS (Haute Autorité de Santé) recalls this definition: “low back pain is defined by pain located between the thoracolumbar hinge and the lower gluteal fold. It can be associated with radiculalgia corresponding to pain in one or both lower limbs at one or more dermatomes. “

Schematically, we can distinguish:

• common low back pain, characterized by low back pain that does not have warning signs. In 90% of cases, common low back pain evolves favorably in less than 4 to 6 weeks, recalls the HAS;
• chronic low back pain, i.e. low back pain lasting more than 3 months;
• the “acute flare of back pain” or acute back pain, or lumbago in everyday language. It is an acute pain, temporary because most often due to a wrong movement, the carrying of a heavy load, a sudden effort (the famous “turn of the kidney”). 

Lumbar disc herniation

A herniated disc is manifested by a protrusion of the nucleus pulposus, the gelatinous part of the intervertebral disc. This hernia will compress one or more nerve roots, causing back pain or pain in the thigh depending on the location of the hernia. If the L5 vertebra is affected, the hernia will indeed cause sciatica characterized by pain in the thigh, descending in the leg towards the big toe.

Lumbar osteoarthritis

Osteoarthritis, which as a reminder is a degenerative disease of the cartilage, can affect the joints between two vertebrae. This lumbar osteoarthritis may not cause any symptoms, as it can lead to bone growths called osteophytes which, by irritation of the nerve, will cause lower back pain.

Lumbar spinal stenosis or narrow lumbar canal

Lumbar stenosis is a narrowing of the central canal of the spine, or lumbar canal, which contains nerve roots. It is most often related to age, and causes difficulty in walking with a feeling of weakness, numbness, tingling in the legs, sciatica occurring at rest or during exertion, and very rarely, paralysis. more or less important of the lower limbs or sphincter functions.

Lumbar disc disease

Degenerative disc disease, or disc degeneration, is characterized by premature aging of the intervertebral disc and progressive dehydration of its central gelatinous nucleus. The disc is then pinched and the nerve roots irritated, which causes pain in the lower back. Degenerative disc disease is also considered to be the main cause of low back pain.

Degenerative lumbar scoliosis

Degenerative lumbar scoliosis manifests itself as a deformity of the spine. It is more common in women, especially after menopause. It manifests itself by back pain and in the buttock, radiating into the thigh, often increased with walking. Degenerative lumbar scoliosis is the consequence of a set of factors: disc failure to which is added a lack of muscle tone, osteoporosis as well as spinal ligament fragility.

Degenerative spondylolisthesis

This pathology linked to the natural aging of the spine manifests itself by the sliding of one vertebra on the other, generally the L4-L5. Lumbar canal stenosis and its symptoms follow.

Lumbar fracture

A fracture of the spine can occur during a very strong impact (road accident in particular). This spinal fracture may be associated with injury to the spinal cord and / or nerve roots, the risk then being paralysis. The fracture can also be unstable, and in the event of secondary displacement lead to a neurological risk.

Low back pain

In its latest recommendations on the management of common low back pain, the HAS recalls that physical exercise is the main treatment allowing a favorable evolution of this pathology. Physiotherapy is also indicated. Regarding drug treatment, it is recalled “that no analgesic drug has proved effective in the medium term on the development of an acute attack of low back pain, but that graduated analgesic management, starting with analgesics level I (paracetamol, NSAIDs), can be implemented to relieve painful attacks ”. The HAS also underlines “the importance of a global care of the patient known as” bio-psycho-social “, taking into account the patient’s experience and the repercussions of his pain (physical, psychological and socio-professional dimensions)” .

Herniated disc

The first-line treatment is symptomatic: analgesics, anti-inflammatory drugs, infiltrations. If treatment fails, surgery may be offered. The procedure, called a discectomy, involves removing the hernia in order to decompress the irritated nerve root.

Lumbar stenosis

The first-line treatment is conservative: analgesics, anti-inflammatories, rehabilitation, even corset or infiltration. If medical treatment fails, surgery may be offered. The procedure, called laminectomy or spinal cord release, involves removing a vertebral lamina to free the spinal cord canal.

Degenerative disc disease

The first-line treatment is symptomatic: analgesics, anti-inflammatory drugs, infiltrations, functional rehabilitation. Surgery will be considered in the event of failure of medical treatment and disabling pain on a daily basis. Lumbar arthrodesis, or spinal fusion, consists of removing the damaged disc and then placing a medical device between the two vertebrae to maintain disc height.

Degenerative lumbar scoliosis

Analgesics, anti-inflammatory drugs and injections constitute the first-line symptomatic treatment. In case of failure and debilitating pain, surgery may be considered. The arthrodesis will then aim to merge the overly mobile vertebral floor and decompress the nerve roots.

Lumbar fracture

Treatment depends on the type of fracture and the associated neurological damage or not. The surgery will aim, depending on the case, to restore the stability of the spine, to restore the anatomy of the fractured vertebra, to decompress the neurological structures. For this, different techniques are used: arthrodesis, spinal expansion, etc.

Degenerative spondylolisthesis

In the event of failure of medical treatment (analgesics, anti-inflammatory drugs and infiltrations), arthrodesis may be considered.

Lumbar spine x-ray

This standard examination assesses the overall morphology of the spine. It is often prescribed as a first-line treatment for low back pain. It makes it possible to detect the presence of degenerative lesions (lumbar osteoarthritis), vertebral compression or morphological abnormalities of the vertebrae, an abnormality of the statics (scoliosis) or a slippage of the vertebrae. On the other hand, it does not always make it possible to diagnose a vertebral fracture. The discs, the spinal cord, the nerve roots being radiolucent structures (they allow X-rays to pass), the x-ray of the lumbar spine does not show herniated discs or pathologies of the spinal cord.

MRI of the lumbar spine

MRI is the standard examination of the lumbar spine, in particular to detect pathologies of the spinal cord. It allows to visualize in 3 dimensions the bony parts and the soft parts: spinal cord, ligament, disc, nerve roots. And thus to diagnose various pathologies of the lumbar spine: herniated disc, degenerative disc disease, disc protusion, lumbar stenosis, inflammation of the vertebral plates, etc.

The lumbar spine CT scan

The lumbar CT scan or computed tomography is the standard examination in the event of a fracture of the spine. It can also diagnose a herniated disc, assess the degree of lumbar stenosis, detect vertebral bone metastases. It is also generally prescribed as part of the preoperative assessment of spine surgeries, in particular to assess the position of the vessels.