I watched a short video in my surgeon’s office on an operation called posterolateral fusion. That’s what I’m going to have done at L45. There wasn’t any narration with the film so I think I got the gist of what’s going to be done. But could you give me sort of a dummied down version of the procedure?

Spinal fusion is a commonly used way to stabilize one or more segments of the spine in older adults. A spinal fusion procedure is also known as a spinal arthrodesis. There are several different ways to perform this operation. The simplest and most often studied technique is the posterolateral spine fusion.

Patients are placed face down (prone) on a special surgical table called a Wilson frame. This frame can be adjusted to place the spine in the exact amount of curvature (flexion or extension) needed to give the surgeon access to the spine while limiting blood loss as much as possible.

To describe the basic fusion procedure in layman’s terms, the surgeon makes the necessary incision down to the bone, then divides the fascia (connective tissue covering the muscles and spine). The muscles are cut away (enough to get to the spine). The surgeon removes the cartilage around the facet (spinal) joint and then removes enough bone along the sides to form a gutter. This depression is where the bone graft will be placed for the fusion.

Screws are used to hold the segments together (one above and one below) until the fusion takes hold. X-rays are used to make sure the screws are in the right spot for optimal stability. Once the screws are in place, additional bone is shaved or cut away, a procedure called decortication. The screws are locked together with a supporting (vertical) rod between the two segments being fused. The final step involves packing the gutters with bone graft material.

It used to be that surgeons would remove some of the patient’s own pelvic bone to use as an autograft (bone donated to oneself). But more and more, bone from a bone bank is used supplemented by newer materials that work much better. These newer graft substitutes are made up of bone marrow, bone morphogenetic proteins (growth factors), and even ceramic material.

One final X-ray is taken to make sure everything is in place where it should be before closing the incision. Patients are followed routinely to make sure the graft material fills in and stabilizes the segment. This may not describe the exact steps your surgeon will take but it may help you make sense of what you saw on the video. It might not be a bad idea to view the video again with this information in hand. And you might want to double check to make sure the film really is without narration — perhaps there is a way to turn on sound that was missing the first time around.