References:
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1 Chapman J R, Hanson B P, Dettori J R. et al .Spine Outcomes Measures and Instruments. 1st ed. Stuttgart New York: Thieme 2007: 81-89
Clinical notes
Farid Kassab, Saudi Arabia
BMP-2 has osteoinductive properties, which gives it a superior role to other bone grafting alternatives when it comes to obtaining fusion. In both animal and human trials it has shown similar if not superior results in increasing the fusion rates in spine and nonspine surgeries. It has also been used to treat difficult cases of nonunions in other sites.
Obtaining a good fusion is one of the basic principles of spine surgery and the research has usually focused on techniques that would increase the fusion rate of any surgery. That is why the interbody fusion techniques were introduced as a stand alone surgery or associated with posterior instrumentation plus or minus pedicle screw fixation. Interbody fusion techniques have shown to have higher fusion rates than PLF techniques, and while 360 ° fusion techniques increase the fusion rate even more, the is at a price of higher complications.
The best fusion technique should decrease operating time, reduce blood loss and decrease graft site morbidity while showing similar or even better results than the gold standard for fusion, which is autografting. BMP-2 has shown all of these characteristics. The only reason why it is not being used extensively, despite all its advantages, is because of its expensive price tag. As of 2007 the cost of 5 ml was $5000. Once this price decreases I expect it will be used more extensively.
Note that the contraindictions for its use are pregnancy, history of cancer, skeletal immaturity, and history of bone tumors.
After saying that a last thought: the assumption of spine surgery has always been as follows: obtaining a sold fusion improves the outcome of surgeries. This is why all the techniques that we use today are directed at increasing the fusion rate. Unfortunately, studies have shown consistently that an increase in fusion rates does not translate into an increase in functional outcomes for patients.
I would like to attract the attention of my fellow colleagues to the must read articles in the Journal of Neurosurgery: Spine 2: June 2005. Every aspect of spine disease and treatments were reviewed. My comments are informed by their findings.
Clinical notes
Ibrahim Tabsh, Saudi Arabia
These two articles shed light on very important points to the enthusiastic and young spine surgeons who are pressured by the industry to try out new products. However, the abundant evidence for the excellent outcome of the autogenous bone grafting technique, the gold standard, with its easy accessibility and affordability, make the change a challenge, especially if expenses must be absorbed by the practice for the new technology.
Comparing the two methods by these randomized clinical trials indicates to me that there is a role for the new and rather expensive BMP in obtaining lumbar interbody fusion with comparable results to the use of autologous bone grafting techniques. Functional outcome and patient satisfaction were the same for the two groups, but expected morbidity from the donor site remains an issue for the autologous option.
These specific studies used allograft with the rhBMP, which carries the potential risks of communicable diseases as for any allograft usage. This risk can be avoided by the use of cages as carriers.
In my practice, I have found that the use of allograft cancellous chips, local autogenous bone graft (posterior surgery mostly) with bone marrow aspirate all mixed together, provides a combination of osteoconductive and osteoinductive material to obtain fusion. The mixture will act as good “filler” for the cages used in the anterior interbody fusions.
Until the rhBMP becomes affordable and approved by the insurance companies or health providers in our region, autogenous bone grafting remains the gold standard in obtaining fusion in spine surgery for the general patient population.
