The lumbar vertebrae in the lower back are the 5 biggest and sturdiest of the vertebrae in the spine and have the strongest muscular support in the spine. This strength is required to support the human torso in an upright, walking position. Fractures of the lumbar vertebrae result, therefore, from either serious disease processes (such as cancer or long-term osteoporosis) or from significant traumatic forces. Likewise, due to the amount of strength and stability required of the lumbar spine, fractures in the lumbar vertebrae can be devastating injuries. Even less significant injuries that alter the proper curvature of the lumbar spine, its support muscles and ligaments, and its postural mechanics can cause sigificant problems in that portion of the body, as well as in the upper levels of the spine which may be stressed by efforts to accommodate the lumbar injuries.
The primary concern in diagnosing lumbar vertebral fractures is to determine the amount of remaining stability in the fracture fragment. This will dictate the need for and the type of intervention that will be undertaken to treat the fractrure. The most common type of fracture resulting from osteoporosis or cancer is called a wedge fracture. Fractures resulting from forceful flexion of the spine (often due to lap seat belts) commonly damage the posterior portions of the vertebrae and disrupt the attached ligaments. Young children are common victims of this type of injury due to the relative lack of strength in their underdeveloped spinal structures. A third type of injury is the burst fracture, which results from force being applied along the length of the spinal column. The “bursting” of the vertebra often resuls in a very unstable fracture which may include significant damage to the spinal canal and spinal cord. Burst fracture can result from falls that cause force to be applied at the end of the spine. For patient ages up through middle age, trauma is the most frequent cause of lumbar fractures. In older age, osteoporosis become the most common cause.
Lumbar vertebral fractures that are severe and unstable to the point of requiring surgery are most often the result of trauma and are most commonly at the upper end of the lumbar spine where it adjoins the thoracic spine. While death from lumbar fractures is rare, the long-term health conditions of these injuries can be very significant, including loss of strength and feeling in the legs and problems with bladder and bowell control.