Bone Grafting
Bone grafting is a surgical procedure that replaces missing bone in order to repair bone fractures that are extremely complex, to reconstruct lost tissue due to pathology, or to prepare the jaws for dental implants.
Bone generally has the ability to regenerate completely but requires a very small fracture space or some sort of scaffold to do so. Bone grafts may be autologous (bone harvested from the patient’s own body, often from the iliac crest), allograft (cadaveric bone usually obtained from a bone bank), or synthetic (often made of hydroxyapatite or other naturally occurring and biocompatible substances) with similar mechanical properties to bone. Most bone grafts are expected to be reabsorbed and replaced as the natural bone heals over a few months’ time.
The principals involved in successful bone grafts include osteoconduction (guiding the reparative growth of the natural bone), osteoinduction (encouraging undifferentiated cells to become active osteoblasts), and osteogenesis (living bone cells in the graft material contribute to bone remodeling). Osteogenesis only occurs with autografts.
Uses for bone grafting procedures
Depiction of mandibular reconstruction bone grafting
- Socket graft preservation for dental implants
- Filling of defects caused by tumors
- Repair of alveolar clefts in cleft lip and palate patients
- Ridge augmentation for dentures or implants
- Augmenting voids in bone caused by trauma
- Sinus Lift Procedure for Dental Implants
The Procedure
The actual procedure being performed with hip grafting.
Bone grafting procedures can be performed with either local anesthesia or IV anesthesia with the exception of major bone grafting. Major bone grafting is usually performed to repair large defects in the face or jaws and the bone is typically autogenous and harvested from the iliac crest (hip), the rib, the tibia, or the skull. These procedures are performed in the hospital with general anesthesia.
Types of Bone Grafts
Autograft
Autologous (or autogenous) bone grafting involves utilizing bone obtained from the same individual receiving the graft. Bone can be harvested from other specific bones, such as from the iliac crest, or more commonly in oral and maxillofacial surgery, from the mandibular symphysis (chin area) or often from the hip, jaw, ribs and skull. This is particularly true for block grafts, in which a small block of bone is placed whole in the area being grafted. When a block graft will be performed, autogenous bone is the most preferred because there is less risk of the graft rejection because the graft originated from the patient’s own body.
Allografts
Allograft bone, like autogenous bone, is derived from humans; the difference is that allograft is harvested from an individual other than the one receiving the graft. Allograft bone can be taken from cadavers that have donated their bone so that it can be used for living people who are in need of it; it is typically sourced from a bone bank.
Xenografts
Xenograft bone substitute has its origin from a species other than human, such as bovine or porcine. Xenografts are usually only distributed as a calcified matrix. Over time, these grafts are resorbed by your body’s natural remodeling processes and are replaced with your own bone.
Platelet Rich Plasma
Platelet rich plasma (PRP) is exactly what the name suggests. The substance is a by-product of blood (plasma) that is rich in platelets. Until now, its use has been confined to the hospital setting. This was due mainly to the cost of separating the platelets from the blood (thousands) and the large amount of blood needed (one unit) to produce a suitable quantity of platelets. New technology permits the doctor to harvest and produce a sufficient quantity of platelets from only a small amount of blood drawn from the patient’s IV during out-patient surgery.
What is the advantage of using PRP?
PRP permits the body to take advantage of the normal healing pathways at a greatly accelerated rate. During the healing process, the body rushes many cells and cell-types to the wound in order to initiate the healing process. One of those cell types is platelets. Platelets perform many functions, including formation of a blood clot and release of growth factors (GF) into the wound. These GF (platelet derived growth factors PGDF, transforming growth factor beta TGF, and insulin-like growth factor ILGF) function to assist the body in repairing itself by stimulating stem cells to regenerate new tissue. The more growth factors that are released into the wound, the more stem cells that are stimulated to produce new host tissue. Thus, one can easily see that PRP permits the body to heal faster and more efficiently.
A subfamily of TGF is bone morphogenic protein (BMP). BMP has been shown to induce the formation of new bone in research studies in animals and humans. This is of great significance to Dr. Mueller when he places dental implants. By adding PRP, and thus BMP, to the implant site with bone substitute particles, Dr. Mueller can now grow bone more predictably and faster than ever before.
Dr. Mueller has been using PRP for over 10 years. He routinely uses PRP for bone grafting, facial and jaw reconstruction and with facial cosmetic surgery. Dr. Mueller has lectured internationally on tissue engineering with the use of PRP and BMP.
PRP Has Many Clinical Applications
- Bone grafting for dental implants. This includes veneer and onlay grafts, sinus lift procedures, ridge augmentation procedures, and closure of cleft, lip, and palate defects.
- Repair of bone defects creating by removal of teeth or small cysts.
- Repair of fistulas between the sinus cavity and mouth.
PRP Also Has Many Advantages
Safety: PRP is a by-product of the patient’s own blood, therefore, disease transmission is not an issue.
Convenience: PRP can be generated in the doctor’s office while the patient is undergoing an outpatient surgical procedure, such as placement of dental implants.
Faster Healing: The super-concentration of the wound with PRP, and thus growth factors, produces an increase of tissue synthesis and thus faster tissue regeneration.
Cost Effectiveness: Since PRP harvesting is done with only 40 – 60 cc of blood in the Doctor Mueller’s office, the patient need not incur the very large expense ($2000 – $3000) of the harvesting procedure in a hospital or at the blood bank.
Ease of Use: PRP is easy to handle and actually improves the ease of application of bone substitute materials and bone grafting products by making them more gel-like.
Frequently Asked Questions about PRP
Is PRP Safe?
Yes. During the out-patient surgical procedure, a small amount of your own blood is drawn out via the IV. This blood is then placed in the PRP centrifuge machine and spun down. In less than 15 minutes, the PRP is formed and ready to use.
Should PRP Be Used In All Bone Grafting Cases?
Not always. In some cases, there is no need for PRP. However, in the majority of cases, application of PRP to the graft will increase the final amount of bone present in addition to making the wound heal faster and more efficiently.
Will My Insurance Cover The Cost?
Unfortunately it does not. The cost of the PRP application (approximately $600 – $700) is paid by the patient.
Can PRP Be Used Alone To Stimulate Bone Formation?
No. PRP must be mixed with the patient’s own bone, a bone substitute material such as demineralized freeze-dried bone, or a synthetic bone product, such as BIO-OSS®.
Are There Any Contradictions To PRP?
Very few. Obviously, patients with bleeding disorders or hematologic diseases do not qualify for this in-office procedure. Check with your surgeon and/or primary care physician to determine if PRP is right for you.