What are the causes of acute lumbar disc bulging?

Lumbar disc bulging is a relatively common spinal disease. Generally speaking, the various components of the lumbar disc will have lesions of varying degrees. When suddenly subjected to some external force, a symptom of protrusion will appear. Generally, after suffering from lumbar disc bulging, there are cervical disc, thoracic disc and lumbar disc herniation according to the different parts of the disease. So what are the causes of acute lumbar disc bulging?

1. Congenital genetic factors

Lumbar vertebrae have vertebral bodies and vertebral arch ossification centers at birth. There are two ossification centers on each vertebral arch, one of which develops into the superior articular process and pedicle, and the other develops into the inferior articular process, lamina, and half of the spinous process. If the two do not heal, congenital isthmic spondylolysis, also known as isthmic nonunion, will form a local pseudoarthrosis-like change. After walking, the upper vertebra may slide forward due to standing, which is called spondylolisthesis. Spondylolisthesis may also occur due to abnormal development of the upper sacrum or L5 vertebral arch, without collapse of the isthmus.

2. Traumatic

The isthmus of the lumbar spine may suffer acute fractures due to acute trauma, especially extension trauma, which is more common in competitive sports or heavy labor porters. 3. Fatigue fracture or chronic strain

From a biomechanical perspective, when the human body is standing, the lower lumbar spine bears a greater load. The force that causes forward displacement acts on the isthmus where the bone is relatively weak. Long-term repeated action can lead to fatigue fractures and chronic strain injuries.

4. Degenerative factors

Due to long-term instability in the lower back or increased stress, the corresponding small joints wear out and undergo degenerative changes. The joints suddenly become horizontal, and coupled with intervertebral disc degeneration, intervertebral instability, and relaxation of the anterior longitudinal ligament, slippage gradually occurs. However, the isthmus remains intact, so it is also called pseudoslippage. It is more common after the age of 50. The incidence rate in women is three times that in men. It is more common in L4, followed by L5 vertebrae. The degree of slippage is generally within 30%.

5. Pathological fracture

It is a systemic or local lesion that involves the vertebral arch, isthmus, upper and lower articular processes, causing loss of stability of the posterior structure of the vertebral body and pathological slippage. Localized bone lesions can be tumors or inflammatory. The incidence of lumbar spondylolisthesis varies with race and region. It is 4-6% in Europe and about 4.7-5% of the total population in my country. Spondylolisthesis caused by isthmus collapse accounts for about 15%, and degenerative lumbar spondylolisthesis accounts for about 35%. In my country, the incidence age of lumbar spondylolisthesis is mostly between 20 and 50 years old, accounting for 85%; the incidence rate is higher in males than in females, with a male-to-female ratio of 29:1. The most common sites of lumbar spondylolisthesis are L4-L5 and L5-S1, with the incidence of L5 vertebra being 82-90%.