When Stacy Pilarski entered Detroit Receiving Hospital early in December month, she was missing 4 to 5 inches of bone from her lower left leg.
In August 1999, a random shooting shattered her tibia and tore muscles and nerves. Unable to walk or play her beloved softball since then, the 31-year-old has been living in various relatives’ homes, making it through the days — and the longer nights — on painkillers. A titanium rod — now a permanent fixture — was implanted in her leg soon after the incident and has kept her leg from collapsing.
During a 2-hour operation recently, the gap in Pilarski’s leg was repaired. The missing bone was replaced with a mixture of Pilarski’s own bone cells (harvested from her blood), a few shavings of bone taken from her left hip area and a chemical to turn the mixture into a paste.
Although it will be months before Pilarski’s leg will be strong enough to walk on, that mixture will gradually convert into her own bone. If an X-ray is taken six months from now, it will be impossible to tell that a segment of bone once was missing.
This exciting new paste, derived from the technique known as autogenous (made from one’s own body) growth factor harvesting, has allowed Pilarski to heal in a way that was impossible even 18 months ago.
Most large medical centers across the country now employ this technique, but Dr. J. Tracy Watson, Pilarski’s surgeon and a Wayne State University professor and orthopedic trauma specialty team member, is renowned in the Detroit area. The team members, Watson says, “were the first ones to employ it in this part of the country, east of the Mississippi.” Few, if any, other countries in the world use the autogenous growth factor, or AGF, technique yet, he says.
Two years ago, physicians would have tried to repair Pilarski’s leg through massive bone grafting, which requires taking bone from other sites of the body and layering it to fill in the area that is missing bone. Doctors would have needed to take bone from at least four sites to fill such a large area, Watson says.
Not only would the grafting have been painful and required extensive recovery time but it also would likely have failed to entirely fill the extensive gap in Pilarski’s leg.
Although Pilarski hardly considers herself lucky to have been randomly shot and suffered such a debilitating injury, she is lucky in her timing.
“Years ago, we would have had to amputate her leg,” Watson says. “Even with this new technique, you don’t lose 5 inches of bone and walk away like nothing happened, without any residual disability. There will be extensive recovery time involved.”
Muscles and nerves of Pilarski’s leg may require extensive physiotherapy and may not entirely heal, but the new bone in her leg will heal completely once the paste has converted into normal bone. She will be able to walk again in a few months, Watson says.
The paste does not heal any faster than regular bone. The breakthrough, Watson says, is that the AGF technique can fill in large areas of missing bone by using mostly natural materials from the body. There is also less recovery time than with a conventional bone graft, and less pain, because bone grafting from the pelvic area requires pieces of bone to be chipped off and moved.
To make the paste, Watson takes a pint of blood from the patient just before surgery. The blood contains multiple bone-growth hormones found in the platelets. Using a cell-saver machine that most hospitals already have to separate blood components, the platelets from the patient’s blood are separated from the other blood components.
The platelets are then concentrated using a pediatric dialysis machine (typically used to clean blood in patients with kidney failure) and the bone growth factors are harvested. The red blood cells are later transfused back into the patient.
While this process is taking place, the surgeon removes small chips of bone from another area of the body, usually the pelvis.
“We scoop it out,” Watson says. “As we harvest the bone, it looks and feels like salad croutons.” For Pilarski’s surgery, about two tablespoons of her bone were needed.
The surgeon then mixes the harvested bone, the platelet growth factors and a chemical binding component (thrombin calcium chloride) into one syringe. Five minutes are allowed for the paste to stiffen. What emerges looks like a very red, small hot dog, with the consistency and color of a horseradish cocktail sauce. The whole paste-making process takes 20 minutes. This material is then placed into the area of the patient’s missing bone and molded to the bone that remains.
“We trowel it in, much like applying mortar between bricks, although in the future, it may be possible to inject the paste,” Watson says.
The area is then closed with suturing.
Within several days, the patient’s growth hormones begin to produce the cells needed to form bone, and eventually normal bone tissue is regrown in the damaged area.
Other uses are being devised.
AGF costs $1,200 to $1,800, depending on the amount of material that needs to be harvested from the patient. The cost is comparable to traditional bone grafting but requires less hospital recovery time.
“With the success of this research, this technique is now a reasonable tool for most surgeons to use,” Watson says.
For Pilarski, the procedure was more than reasonable.
“It’s been really hard to not be mobile and able to get up and go. But I can get on with my life. I don’t have to depend on anybody.”
