The fusion is accomplished when the graft material placed between the two bones of a motion segment induces bony incorporation on both sides and heals them together as one bone. This eliminates motion but also hopefully reduces the pain from that segment of the spine.
Bone Graft Types
There are a number of different types of bone grafts that can be used for spinal fusion:
- Synthetic bone graft substitutes (man made)
- Allograft (cadaver bone from a bone bank)
- Autograft (bone graft taken from the patient’s own body).
Bone graft material can be morselized into small pieces or used as larger pieces for structural purposes to help achieve a spinal fusion.
What Is Bone Graft Site Morbidity?
Graft site morbidity refers to any consequences that result from the harvesting of the patient's own bone (an autograft). Undesirable side effects and complications that can result from the bone graft harvesting procedure include early post-operative pain, chronic pain, scarring, bleeding, infection, and more.
In spinal fusion surgery the most common site for obtaining autograft bone is from the portion of the pelvis called the iliac crest - the boney prominence around the belt-line of the hip. The bone graft can be harvested from the front (anterior iliac crest) or from the back (posterior iliac crest) of the pelvis. The ilium is also a source for harvesting bone marrow aspirate, which contains cells that serve to stimulate bone formation.
The incidence of donor site pain, or pain related to bone graft harvesting for spinal fusion, varies greatly and has been reported to persist for over 3 months in 2.8% to 39% of patients. Pain lasting for up to 2 years has been reported in 15% to 39% of patients.1,2