Evolution of Technology

Posterior Lumbar Instrumented Fusion

Posterior Lumbar Instrumented Fusion (PLIF) is a technique performed to achieve spinal fusion in the low back (lumbar spine). While there are many approaches to achieve fusion this one is performed through a direct posterior approach to the back and works by inserting a cage made of synthetic material (plastic or metal) with bone graft directly into the disc space. A cage serves as a space holder between the diseased vertebrae and allows bone to grow through it, eventually becoming a part of the spine. During a PLIF a 3-6 inch incision is made in the patient’s back and the spinal muscles are separated to allow access to the vertebral disc. The surgeon then carefully removes the back of the vertebrae (lamina) to be able to see and access the nerve roots. The affected disc is then removed and the adjacent vertebral bone surfaces are prepared for fusion. Once the disc space is prepared, bone graft, a metal cage, or other biologic materials are inserted into the disc space to promote fusion between the vertebrae. Rods and screws may also be added to maintain stability and hold the graft in position.

Evolution of Procedure

Lumbar Decompression and Fusion

Surgery for degenerative spondylolisthesis may be warranted in cases where there is persistent, incapacitating pain or neurologic dysfunction. Decompression of the nerves and fusion is the treatment of choice to prevent disease progression, manage pain and provide neurological relief. In this procedure, the spinal canal is widened by removing or trimming part of the vertebrae (lamina). This creates more space for the nerves and relieves pressure on the spinal cord. Fusion is then performed to permanently connect the unstable vertebral segments together to prevent further slippage and stop motion within that segment. There are multiple techniques to fuse the spine to include using metal, plastic or bone graft, and varying approaches to access the spine through either the front (abdomen), sides, or back.

Evolution of Diagnosis

Degenerative Spondylolisthesis

Degenerative spondylolisthesis is a wear and tear phenomenon which describes the condition of one vertebrae slipping over the vertebrae below. This condition more commonly affects the lumbar spine (low back) and is found in older patients typically >60 years old. When the vertebra slips forward, it can compress nerve roots and cause low back pain or radiating pain to the legs. Some people with spondylolisthesis are symptom-free, however most experience some form of low back pain, leg pain/weakness, muscle spasms, and/or difficulty walking. Most of the time this condition can be managed without surgery with bracing, physical therapy, muscle relaxants, and anti-inflammatory medications. Degenerative spondylolisthesis can be progressive, and once it causes neurologic dysfunction surgery may be warranted.