Lumbosacral fusion is a surgical procedure that fuses vertebrae together in the lumbosacral region of the spine, when necessary as a result of degeneration and diseases that affect the area, such as a herniated or ruptured disc, vertebral compression fracture or degenerative spondylolisthesis.
Lumbosacral fusion surgery often is performed in tandem with another surgery that deals with the underlying problem. For example, if a herniated disc in the lumbosacral area of the spine is the problem, the spine surgeon first removes the damaged disc. Then the surgeon inserts bone graft material to replace the herniated disc so that the two vertebrae fuse together. The fusion of the two vertebrae restores stability to the spine.
The lumbosacral area of the spine is the point where the last vertebra of the lumbar spine (lower back) connects to the first vertebra of the sacral spine (below the lumbar, it is part of the pelvic region). The five lumbar vertebrae experience a great deal of motion and flexibility and also have an important weight-bearing function. The sacral vertebrae consist of five bony segments that form a triangle. The lumbosacral joint is very involved in movement including walking, running, twisting, jumping, bending and lifting. That's why the lumbosacral spine is highly susceptible to debilitating problems and conditions. The lumbosacral segment, where the lumbar and sacral regions meet, is prone to degeneration and disease.
Lumbosacral spondylosis is the general term for a variety of degenerative spinal abnormalities that may protrude into the spinal canal, exerting pressure on spinal nerves where the last vertebra of the lumbar spine and first vertebra of the sacral spine connect. When severe, these conditions can be repaired with lumbosacral fusion surgery:
- Degenerative spondylolisthesis – A condition in which a bone (vertebra) in the lower (lumbar) part of the spine slips out of its proper position onto the bone below it as a result of a degenerative disease such as arthritis.
- Vertebral compression fractures – These happen when the vertebrae are compressed together to a smaller height. The leading cause of this type of fracture is osteoporosis, a degenerative bone disease that thins and weakens bone tissue as people age. Osteoporosis makes bones brittle and more vulnerable to fractures.
- Bulging or ruptured discs – In the spine, discs act as shock-absorbing cushions between the vertebrae and keep the bones from rubbing against each other. When discs are damaged by injury, disease or normal wear and tear, they may bulge or rupture outside of their normal position and press on nerves. A ruptured or herniated disc can cause extreme pain in the lumbosacral joint.