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  • Writer's pictureFayette Williams, DDS, MD

Should bone be placed immediately or later?

Updated: Feb 13, 2021

Replacing missing jaw bone removed during tumor surgery is important to restore the facial profile, maintain chewing ability, and to provide a platform for new teeth. There are multiple options to replace missing bone. Some methods are possible at the same time as tumor removal, and other options must be delayed a few months.

Immediate replacement of bone is most predictable with a vascularized bone transplant from another area of the body. This is most commonly done with the fibula from the leg. The fibula is harvested with the blood vessels supplying the bone and re-attached to vessels in the neck. Because this bone has it's own blood supply, it has a very high survival rate (95%). Most patients do surprisingly well giving up this small bone because the larger bone (the tibia) remains. Dr. Williams'team has performed this surgery on a marathon runner, a cyclist, and a power lifter who continue their sports. While there is never a guarantee that problems will not develop after such a complex surgery, most patients tolerate giving up their fibula quite well. When there is a choice, Dr. Williams prefers to use the LEFT fibula because there is less interference with your driving ability during the early stages of recovery.

Another advantage of the fibula is that soft tissue from the leg (skin) can be taken with the fibula to replace soft tissue in the mouth removed with the tumor.

Immediate replacement of bone is most predictable with a vascularized bone transplant from another area of the body. This is most commonly done with the fibula from the leg.

To determine if you are a candidate to use your fibula, a special xray of the leg blood vessels (angiogram or CT angiogram) is performed to verify the blood vessels are suitable. In normal leg anatomy, there are 3 vessels running to the foot. One of these vessels (peroneal) is taken with the fibula, leaving two vessels to supply the foot. Two vessels are perfectly adequate if they have normal flow to the foot. In some patients (5%), there can be anatomical variations where fewer than three vessels supply the foot. Other patients have vessel blockages which render removal of the fibula and it's vessel unsafe.

What about Delayed Bone Reconstruction?

In some cases, reconstructing the bone defect at a later date makes sense. If there is uncertainty in the ability to remove all the tumor then a surgeon might recommend waiting for the final pathology report before adding new bone. While the reconstructive process is important, we must first ensure that all the tumor is removed. The surgeon's experience is important here and there are certain locations and radiographic features that might make your surgeon less confident that all the tumor can be removed on the first attempt.

While a vascularized fibula reconstruction can usually be performed at the same time as tumor removal, not all surgeons are trained in fibula reconstruction. Most surgeons are only trained in non-vascularized bone reconstruction since additional fellowship training is needed for vascularized bone reconstruction such as a fibula flap. This involves harvesting bone from areas such as the hip. This bone is packed into the defect and relies on the surrounding soft tissue to bring in a new blood supply. These non-vascularized grafts have a higher infection rate since the blood supply is poor, especially for larger grafts. The oral cavity is full of bacteria and exposure to the mouth increases the risk of infection. Therefore, some surgeons choose to let the defect heal after tumor removal, then place non-vascularized bone a few months later through the neck, avoiding the contaminated mouth. However, the higher infection rate still remains. This has its own challenges since it can be surprisingly difficult to position the new bone in the correct location without being able to view it from the mouth. And infection is still a risk which can result in loss of the entire bone graft.

Another option is tissue engineering. This involves a triad of three materials to grow new bone. The three ingredients include BMP (Bone Morphogenic Protein), BMAC (Bone Marrow Aspirate Concentrate) and allogenic bone (cadaver bone). While this explanation is overly simplified, I'll give it a try. The BMP is a protein which acts as a signaling molecule to tell the BMAC to turn into bone. While BMP comes in a package off the shelf, BMAC comes from the patient's bone marrow. Instead of a large incision, a needle is placed into the hip bone to draw out marrow and stem cells. These stem cells are instructed by the BMP to turn into bone. Since BMP and BMAC are liquids, cadaver bone is used to form a "matrix" to maintain the space to grow new bone. These three ingredients are mixed together in a wet mushy slurry and placed into the defect. The main advantage of this tissue engineering approach is that it lets you keep your fibula in your leg. The disadvantage is that it does not allow immediate dental implant placement and actually takes 9-12 months before it is solid enough to place implants. An additional disadvantage is that it often must be done in a delayed setting. Lastly, the BMP produces tremendous swelling and many patients must have their jaws wired shut for 3-4 weeks because the swelling of the gums can cause the opposing teeth to bite a hole into the gums and lead to exposure to the mouth and infection.

When faced with the challenge of jaw reconstruction, it's in your best interest to see a surgeon trained in all types of jaw reconstruction. Our team performs vascularized grafting (fibula, scapula), non-vascularized grafting (iliac crest) and tissue engineering (BMP). There is no "one size fits all" method and some patients will have better success with one method over another.

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