Becker's Spine Review

38 Spine Devices & Technology 8 Important Spinal Technology Advances Heading Into 2013 By Laura Miller Here are eight important spinal technology advances heading into next year. 1. Artificial discs. Much controversy circles around the future of artificial disc replacements. Lumbar disc replacements have not held up under scrutiny and researchers studying cervical disc replacements are just beginning to gather long term effectiveness data. "Lumbar disc replacement is dead in the water, but there is a lot we are still excited about with cervical disc replacement," says Andrew Hecht, MD, co-chief of orthopedic spine surgery at Mount Sinai School of Medicine in New York City. "Now we are seeing some evidence that in its current form, cervical artificial discs aren't preventing adjacent segment disease as we had hoped. Cervical fusion is such a successful procedure that the key is really going to be whether disc replacement really does reduce the rates of adjacent segment disease." At this year's North American Spine Society annual meeting, studies presented compared cervical disc replacement and fusion procedures and showed minimal, if any, difference in adjacent segment disease. However, there are promising developments on the horizon for artificial discs. "One of the shortcomings of the United Statesapproved lumbar discs is they do not incorporate shock absorption while some of the European ones do," says Donald Corenman, MD, a spine surgeon with The Steadman Clinic in Vail, Colo. "The currently available ball and cup disc replacements are not mechanically connected so there are no significant stresses created in the interface between the vertebral body bone and the implant itself. With a shock absorption type of disc, there is a strong mechanical connection between the two ingrowth endplates. This creates greater mechanical stress between the host bony endplate and the device. Longevity of the implant comes into question. Nonetheless, I think this will finally yield disc implants that are more acceptable for the lumbar spine." Regardless of the method, surgeons are looking for ways to preserve motion in the spine and new developments in disc replacements may give patients more normal motion than in the past. "We continue to get closer to having actual metal and plastic options that really more closely mimic the movements and kinematics of the normal human cervical spine and disc," says Sheeraz Qureshi, MD, associate professor of spine surgery in the department of orthopedics and chief of trauma in at Mount Sinai School of Medicine in New York City. "We are getting longer term results on disc replacement options that are available, which have had excellent outcomes. We continue to improve the type of motion that is occurring and we are getting closer to the point where we can say we will have these devices to protect against adjacent segment disease." 2. Minimally invasive surgery for instrumentation and fusion. Minimally invasive techniques are now the standard of care for simpler procedures like decompressions and are gaining traction among instrumentations and fusions. While maverick surgeons have been performing these procedures for several years, more studies now show their effectiveness and the idea of minimally invasive spinal surgery has gone mainstream. "Now that we have done this for quite some time, we are seeing a lot more papers discussing how effective minimally invasive surgery is compared to mini open techniques," says Dr. Hecht. "We are trying to figure out where these procedures will fit in and whether the differences are really enduring. For cervical foraminotomy and far lateral discectomies, the minimally invasive techniques are the gold standard; for spinal fusion, the jury is still out on whether it makes a difference." For some procedures, such as transforaminal lumbar interbody fusions, the minimally invasive technique might shorten hospital stays by a day, but the patient might not achieve fusion as well as the mini open technique would have. "We need to have a minimally invasive technique that will allow us to achieve as good of a fusion there," says Dr. Hecht. 3. Lateral access procedures. Device companies are increasingly developing instrumentation for lateral access techniques. These techniques allow surgeons to access several different areas of the spine through a minimally invasive approach. "Initially, minimally invasive surgery was just percutaneous pedicle screw placement, but as things evolved we were able to do more TLIFs and fusions, and now we are seeing the increased popularity of direct lateral surgery," says Dr. Qureshi. "The next thing on the horizon will be the ability to more safely access not only the L4-5 space through a minimally invasive direct lateral approach, but also the L5-S1. Before this area wasn't considered a space that could be accessed through those approaches, but if we are able to do that it would be a major advancement." Dr. Donald Corenman Dr. Sheeraz Qureshi The lateral approach has also brought forth several new innovations in image guidance. "We are very excited about the improvements in image guidance technology that allows us to do these less invasive procedures more safely because when you have an idea of where you are and how close you are to directly accomplishing the goals of surgery, you have better outcomes," says Dr. Qureshi. "We are seeing improved ability to navigate and access levels commonly involved in surgery that weren't possible even through lateral approaches before. In 2013, we will be introducing some new ways to do that." 4. Implant and instrumentation materials. Spinal instrumentation is constantly being refined based on the metal material, shape and technique. Every major manufacturer routinely updates their instrumentation and while the application of the instrumentation hasn't changed much, the metal material has. "There is a trend, in spinal deformity surgery, to use cobalt chrome for longer constructs. This

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