MDNews - Cleveland-Akron-Canton

+ +++++++++++++++++++++++++++++++++++++++++ + +++ +++ +++++++++++++++++++++++++++++++++++++++++ SPECIAL SECTION: NEUROSCIENCE New Options for Spinal Surgery: By Dane L. Donich, MD F OR MANY YEARS the standard of care for performing spinal fusions involved the harvesting and implantation of autograft bone. Even today the gold standard for spinal fusions continues to be the harvesting of a patient's iliac crest "hip graft." In many cases patients experience significant morbidity with hip graft harvesting including prolonged pain, increased blood loss and surgical time as well as wound healing issues. As a result, much effort has been focused on the development of viable alternatives to a hip graft. These alternatives are either less invasive or in some cases non-invasive. Perhaps the most signifi cant develop- ment for grafting is the use of Bone Morphogenic Protein (BMP). A naturally occurring substance for human bone growth, BMP is now produced com- mercially and is being utilized for spinal fusions throughout the U.S. with nearly 1 billion dollars of sales annually. It is used as a substitute for hip autograft and is applied via collagen BMP-soaked sponges. It does not require any additional incisions or bone marrow aspiration and saves the patient considerable pain and morbidity. It is the only option available that, by itself, has been demonstrated to be equivalent to hip autograft in its ability to achieve bone growth and fusion. Limitations include a maximum lifetime dosage, non-use in patients with malignancy, non-use in potentially reproductive females and non-use in anterior cervical spine surgeries. The most common complication reported is a very low incidence of excessive bone growth. In my experience, it has proven to be well tolerated, with signifi cantly less morbidity than iliac crest autograft and is now used frequently for lumbar spinal fusions. By far, BMP commands the largest market share world wide for autograft alternatives. Another alternative to iliac crest grafting is bone marrow aspiration from the iliac crest or vertebral body that is then applied to a synthetic bone growth promoting material or allograft. This is less invasive than an open iliac crest graft but still involves some morbidity due to multiple needle passes into the area of harvest. It is not generally considered to be equivalent to an open iliac crest auto- graft in its ability to achieve bone growth and fusion. Some promise has been shown when combining this technique with centrifuge and the concentration of stem cells or platelet rich plasma in enhanc- ing fusion rates. These concentration techniques are relatively new with sparse data and are not widely used at this time. There has been much fanfare sur- rounding the development of artifi cial or prosthetic discs for the cervical and lumbar spine regions. The rationale for an artificial disc includes motion preservation, less risk for an adjacent segment disc problem, above or below the involved disc, in the future. In theory, a good artifi cial disc would eliminate the need for most spinal fusions. Intuitively, it makes good sense. There are now commercially available cervical and lumbar artifi cial discs. There 20 | Cleveland-Akron-Canton MD NEWS MDNEWS.COM SEPTEMBER-OCTOBER 2011 Fusion Without Bone Graft and Prosthetic Disc Replacement Surgery are specifi c limitations regarding which spinal levels and how many levels can be fused. There are also contraindications including neural compression in the lumbar spine due to disc herniation (or recurrent disc herniation with prior surgery) or degenerative stenosis. Expectations for sales of artifi cial discs were very high but have not been achieved. Currently, artifi cial discs are implanted in only a very small percent- age of patients, with the vast majority of these patients receiving spinal fusions. Reasons for the relative failure of artifi cial discs thus far include a higher complication rate than expected as well patient satisfaction outcomes that are not superior to spinal fusion. In addition, they have been plagued with initial costs that are often higher than spinal fusion and insurance companies are reluctant to pay for it as it has not been proven to the satisfaction of most surgeons to be superior to spinal fusion. As a result, artificial disc surgery is rarely performed and cannot be said to represent the standard of care in most areas of the U.S. It's expected there will be improvements with each subsequent generation of artifi cial disc, with lower complication rates improved outcomes. Ultimately, it will likely lead to the widespread adoption of artifi cial discs. Dr. Dane Donich is a neurosurgeon and a member of the medical staff at Summa Barberton, Summa Wadsworth-Rittman Hospital, Summa Akron City and St. Thomas Hospitals and Robinson Memorial Hospital, an affi liate of Summa Health System. n

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