Over the last 30 years, minimally invasive technology has developed rapidly in spine surgery, with many technologies demonstrating significant clinical advantages, but others promising more than they could deliver and largely falling by the wayside.
Seven spine surgeons discuss which technologies are here to stay and which could be a flash in the pan.
Ask Spine Surgeons is a weekly series of questions posed to spine surgeons around the country about clinical, business and policy issues affecting spine care. We invite all spine surgeon and specialist responses.
Next week's question: What needs to change for endoscopic spine surgery to become more widely adopted in the U.S.?
Please send responses to Alan Condon at firstname.lastname@example.org by 5 p.m. CDT Wednesday, July 28.
Note: The following responses were lightly edited for style and clarity.
Question: Which minimally invasive technology trends are a fad and which are here to stay?
Peter Derman, MD. Texas Back Institute (Plano): I anticipate that motion preservation via disc replacement and minimally invasive and endoscopic decompressions will increasingly be utilized. For this to happen, training in these techniques must become more widespread; we must continue to produce high-quality evidence supporting their use; and the reimbursement system must change to reflect the value generated by these operations compared to fusion. Continued innovation with development of arthroplasty devices that can be used in the setting of deformity and instability will ultimately help even more patients avoid fusion.
I believe that the recent explosion in the use of interspinous and interlaminar spacers will subside just as it has in the past. I am skeptical that the long-term data will demonstrate meaningful benefit. Furthermore, the argument that these devices are useful in patients who are too old or frail for a direct decompression is flawed — advanced surgical techniques allow us to perform laminectomies via comparable (or smaller) incisions with minimal blood loss. General anesthesia may not even be necessary if endoscopic techniques are employed, and patients can go home the same day. Why insert a kyphosis-inducing implant when a nondestabilizing direct decompression is an option?
Joseph Lee, MD. Rothman Orthopaedic Institute (Philadelphia): Minimally invasive surgery has continued to evolve in the last 30 years. However, the goals of minimally invasive spine surgery remain constant: nerve decompression and spinal stability. Advances in navigation, robotics and augmented reality will continue to evolve together and allow surgeons to perform minimally invasive surgery safely and efficiently. The next frontier will be merging information from MRI and CTs to allow robots to assist in exposure, neural decompression and disc space preparation. Advances in interbody technology such as surface modification and multiplanar expansion capabilities facilitate achievement of fusion and sagittal plane correction. The traditional lateral MIS approach remains a successful surgical technique for a variety of degenerative spinal conditions. The recent introduction of the single-position prone lateral technique has been successful, with its proposed advantages of superior OR efficiency, better sagittal correction and ability to incorporate navigation/robotics. Endoscopic spine surgery, or "ultra-minimally invasive surgery," has become more popular in the last few years, but it has yet to be determined if this technique provides superior clinical outcomes compared to traditional minimally invasive techniques.
James Mok, MD. NorthShore Orthopaedic & Spine Institute (Skokie and Des Plaines, Ill.): Here to stay are expandable interbody cages, which facilitate restoration of disc height, maximize footprint, and minimize the amount of trialing and energy of insertion. These attributes further enable the minimally invasive surgeon to achieve the goals of interbody fusion. The continuing advances in cage designs make this a minimally invasive technology with staying power.
On the other hand, prone lateral interbody fusion, a variant of the established MIS lateral retroperitoneal interbody fusion, might prove to be a fad. It is performed in the prone position, and although an interesting concept, several problems may preclude widespread adoption. While there is only a single major value proposition — the time savings in repositioning (the "flip") — the prone position has several potential drawbacks, including gravity dragging retroperitoneal fat and other soft tissues into the field of view, making disc space prep and implant insertion challenging. But the major concern is safety. It is easier to consistently maintain a safe working angle (vertical) with the patient in the lateral decubitus position than the prone position (horizontal). This is critical considering the adjacent structures such as the great vessels. The effect of gravity on the lumbar plexus — considered the structure most at risk in the lateral approach for interbody fusion — is yet to be defined. Surgeons must carefully weigh the benefit of saving time against these safety considerations when evaluating prone lateral interbody fusion.
Ali H. Mesiwala, MD. DISC Sports & Spine Center (Newport Beach, Calif.): Minimally invasive surgery is fast becoming the norm across all specialties. However, the concept of MIS can be confusing for many patients. In traditional spine applications, MIS refers to the use of smaller incisions or multiple stab incisions to replace large open incisions and operations. This minimizes blood loss, anesthetic time and complications. Any MIS and related technologies that achieve these endpoints will be adopted, modified and improved upon, and are here to stay.
The MIS trends, however, that are likely to be transient are those which have been used in spine surgery in the past and have been abandoned by surgeons, only to be repackaged and reapplied by other specialists in traditionally nonsurgical fields. Prime examples of this are spinous process distraction devices for the treatment of lumbar stenosis, posterior sacroiliac fusion using allograft dowels, and needle/shaving devices used for ligamentum flavum removal as a replacement for traditional laminectomies.
Procedures which allow us to take advantage of the body's natural corridors and orifices are here to stay. Those operations that can be done more safely, effectively, efficiently and reproducibly through small incisions will also be the ones that we continue to utilize. Lastly, advances in medical device design will also streamline surgery and make it less invasive.
Hooman Melamed, MD. Hoag Orthopedic Institute Surgery Center - Marina del Rey (Calif.): The field of endoscopic spine surgery, which I would consider is ultra-minimally invasive, is going to become the preferred and a better alternative choice for patients who not only require decompression, but even more importantly, save many patients from having fusion done, where, with the power of endoscopy, one can perform a very thorough extraforaminal decompression without destabilizing the spine and decompressing nerve roots and obviate the need from doing any interbody grafting and fusion. You are preserving most of the normal anatomy with very minimal blood loss, much lower risk of infection and way faster recovery. Most importantly, you're not burning any bridges with this approach. These surgeries all can be done outpatient and most of them going home the same day.
I also think robotic spine surgery — just like how robotics advanced in urology and other general surgery procedures — is going to continue to advance in spine, where I can potentially see where the robot is performing the endoscopic decompression, performing precise osteotomy cuts and placing pedicle screws.
However, I would be very wary about advertising laser spine surgery as it does not have a big consensus for good outcomes or advertising minimally invasive procedures as nails and a hammer where every single surgery can be done that way.
Not every decompression or fusion can be done as minimally invasive. Unfortunately, there's recently more bad results of spinal deformity surgery that are being done minimally invasive with suboptimal outcomes that require a major revision reconstruction. There will always be spinal deformity cases that should be done with a traditional open approach.
Brian Gantwerker, MD. The Craniospinal Center of Los Angeles: By looking backward, we can see that very few MIS technologies have completely phased out. There are technologies that perhaps have not had their moment as of yet. I have seen some companies with innovative solutions, for instance for interbody constructs, especially stand-alone transforaminal lumbar interbody devices that probably need two to three more revisions as well as peer-reviewed studies conducted to properly select patients. The fad technologies can often be found in the dustbin of the last 20 years. And perhaps not justifiably so. Not to name names, but we can all give examples of things we really miss and liked that have been relegated to the elephant graveyard. I think you can predict the ones that will endure are technologies that make you work faster or do something you already do in a novel, faster or safer manner.
John Burleson, MD. Hughston Clinic Orthopaedics (Nashville, Tenn.): I think endoscopic spine surgery might finally be ready to make it. Those utilizing this technique are more enthusiastic than in the past and the technology to support it has expanded. As with most technologies, I believe the real key to new technology sticking is their utilization at teaching programs. As more residents and fellows are exposed to endoscopic spine surgery, they will perform these procedures from the beginning.