In the last several months, the National Scoliosis Foundation (NSF) has received a number of inquiries regarding the anterior and posterior surgical techniques used to correct scoliosis. To find out more about these procedures, NSF asked Dr. Howard King, Clinical Associate Professor of orthopaedic surgery, University of Washington, and Northwest Spine and Pediatric Orthopaedic Surgeons Seattle, Washington. What follows is an excerpt of a conversation between Nancy Schommer and Dr. King.

Q: Dr. King, let's start with some basic definitions of these terms.
A: Posterior refers to the back of the spine, while anterior means the front of the spine. With the posterior approach, we make our incision down the middle of the back. With the anterior approach we will make an incision along the right or left side of the body, depending upon the direction of the curve.

Q: Is the surgical procedure the same for the posterior and anterior approaches?
A: Scoliosis surgery involves straightening the curve and stabilizing the spine, either with bone grafts (fusion) or spine instrumentation, and in most cases both. These steps are essentially the same for posterior and anterior surgery. The primary difference is that in the anterior approach we have access to the larger part of the vertabra for fixation of spine instrumentation, and we can also remove the discs in between the vertabra to free up the spine and gain better correction.

Q: Can anterior surgery be used in all situations?
A: No, anterior surgery is not indicated in all situations. Additionally, it is a more complex procedure and therefore has more potential risk. In scoliosis surgery our goal is to get the best correction and stability we can while fusing the least amount of vertebral segments possible and minimizing surgical and post-surgical complications. Using different approaches or a combination of them helps us to achieve that goal.

Q: Generally speaking, when do surgeons use the posterior approach and when do they opt for anterior?
A: For scoliosis, posterior surgery is primarily for single thoracic and double (thoracic/lumbar) curves. Anterior surgery may be used for a lumbar or thoraco-lumbar curve.

Q: Under what circumstances would you do both anterior and posterior procedures?
A: We would do both procedures on someone who has a very large, stiff, rigid curve a situation where we're trying to help the person gain spine correction. We'd also do both on an adult who needed a very long fusion down to the pelvis, and on a young child who has a lot of growth left. We would also do both procedures on someone with significant kyphosis; the combination of the two approaches would give the best correction and stability.

Q: Why would anterior/posterior surgery be done on the young growing child?
A: In the young growing child we would want to avoid what's known as "crank shafting." If a child is very young, 8 or 9, and hasn't yet gone through his or her rapid growth phase, a posterior fusion alone would stop the growth of the posterior portion of the spine, but the anterior portion would continue to grow and the scoliosis would continue to worsen. The anterior procedure would be done to arrest that anterior growth.

Q: When you do both procedures, do you do them in stages a few days apart, or on the same day?
A: If we were faced with a really complicated reconstruction we may opt for stages. But generally speaking, we usually do both procedures on the same day: we start with the anterior portion to free up the spine, and then continue with the posterior portion.

Q: What is the advantage of doing both procedures on the same day?
A: One advantage is we reduce the overall time that the patient is under anesthesia and that helps reduce recovery time. By doing both procedures on the same day, we can also reduce the amount of time the patient spends in the hospital. With surgeries on the same day, a patient might spend 5 days in the hospital, versus two weeks for a patient who had the surgeries in stages. We also know from good studies that post operative nutrition and blood clotting factors are better with same day procedures.

Q: Any final thoughts on anterior and posterior approaches?
A: Just a reminder to readers: when it comes to surgery for scoliosis, every case is different—one particular approach will not work for everyone.

Reprinted from:
The Spinal Connection
A biannual publication of the
National Scoliosis Foundation

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