San Diego Spine Foundation


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Spinal fusion with instrumentation

Patients with chronic back pain or spinal instability may require spinal fusion surgery. Spinal instability is defined as the displacement or deformity of the spine that weakens it and creates risk of injury. Spinal fusion surgery is done to stabilize and strengthen the spine and to alleviate severe, chronic back pain. At the San Diego Center for Spinal Disorders, we use spinal fusion surgery to treat spondylolisthesis, scoliosis, severe disc degeneration or spinal fractures. However, we usually only consider fusion after non-operative therapies have failed.

What is fusion?

Spinal fusion is the joining or fusing of two or more vertebrae. Bone graft is traditionally used to facilitate fusion. This involves small amounts of bone being taken from the patient's pelvis (autograft), or from a donor (allograft), and then packed between the vertebrae in order to "fuse" them together.

Specially designed implants (including cages, rods, hooks and screws) are also often used in a fusion surgery. The implants are used to ensure correct alignment between vertebrae and to help successful fusion to take place. In addition, these implants add strength and stability to the spine while healing progresses.

A fusion is not always achieved after surgery. Fusion rates vary depending on factors such as whether or not the patient smokes, number of previous procedures and the underlying pathology. However, there has recently been a breakthrough relating to fusions. Surgeons are now able to use bone substitutes such as bone morphogenetic proteins (BMPs) and other material during surgery to facilitate fusion. BMP is a "substance" that causes bone growth. The use of BMP in fusion surgery is already improving fusion rates. To read more about BMP, click here


These are interbody (between vertebral bodies) fusion techniques used to treat chronic low back pain are PLIF and ALIF.

PLIF stands for Posterior Lumbar Interbody Fusion. It is a fusion technique done from the back (posterior) of the lumbar spine. The PLIF procedure involves three basic steps:

  1. Pre-operative planning and templating.   Before the surgery, the surgeon will use MRI and CT scans to determine what size implant(s) the patient will need.
  2. Preparing the disc space.   An incision is made and back muscles are retracted to allow access to the vertebral disc. The surgeon then carefully removes the affected disc and surrounding tissue.
  3. Implants Inserted.     Once the disc space is prepared, bone graft, and an implant such as a cage, is inserted to promote fusion between the vertebrae. Additional implants may also be used at this time to further stabilize the spine.

ALIF, which stands for Anterior Lumbar Interbody Fusion, is similar to PLIF, except it is done from the front (anterior) of the body.


For some spinal disorders, we may recommend spinal fusion surgery. If so, rest assured that the surgeons at SDCSD are highly skilled with spine fusion techniques. In addition, we use new tools such as BMPs to further enhance the likelihood of a successful fusion.

If you have any questions or concerns about spinal fusion surgery, please speak with your surgeon.