Introduction
Minimally invasive spinal fusion surgery is a procedure designed to connect two bones in the spine to alleviate back pain and address spinal instability. Traditional fusion techniques often required extensive incisions, disruption of surrounding muscles, and prolonged hospital stays. However, advancements in surgical methods have introduced minimally invasive posterior fusion, which employs smaller incisions and spares muscle tissue. This approach leads to less postoperative pain, decreased blood loss, shorter hospitalizations, and faster recovery times.
Anatomy
The spine is made up of a series of bones known as vertebrae, which are organized into distinct regions based on their shape and function. The cervical spine consists of seven small vertebrae in the neck. The thoracic spine, located in the chest, contains twelve vertebrae, while the lumbar spine is found at the lower back, consisting of five larger vertebrae. The lower vertebrae are often fused or variably shaped to connect with the hip and pelvic bones.
Each vertebra has a back section called the lamina, which forms a protective arch over the spinal canal. This central opening houses the spinal cord, nerves, and blood vessels that facilitate communication between the brain and the rest of the body. Intervertebral discs, positioned between each pair of vertebrae, consist of strong connective tissue. Their outer layer, known as the annulus fibrosus, surrounds a gel-like center called the nucleus pulposus, which retains about 80% water. These discs and the facet joints between the vertebrae enable movement, provide stability, and act as shock absorbers to protect the spinal column.
Causes
Minimally invasive posterior fusion is indicated for patients experiencing back pain or leg symptoms due to specific spinal conditions, including spondylolisthesis, degenerative disc disease, traumatic injuries, compressed spinal nerves, and recurrent disc herniation. The surgery can be performed on both thoracic and lumbar spinal levels.
Symptoms
Candidates for minimally invasive posterior fusion typically present with low back pain or radiating pain that extends to other areas of the body.
Treatment
This surgery is performed in a hospital setting, with the patient positioned face down. Utilizing X-ray guidance, the surgeon makes two small incisions in the back and uses retractors to gently separate the muscles for access to the spine. The lamina is then excised, allowing the surgeon to inspect the nerve roots.
Next, the affected disc is removed, and a bone graft along with a structural support cage is inserted. Rods and screws are placed for additional stability, after which the retractors are removed, and the incisions are closed.
Recovery
Due to the smaller incisions and preservation of muscle tissue, patients typically experience less blood loss, reduced trauma to surrounding soft tissues, decreased pain, shorter hospital stays, and expedited recovery. Over time, the vertebrae will fuse together, enhancing spinal stability. The surgeon will advise when it is appropriate to begin physical therapy.
