Domagoj Coric, MD, chief of neurosurgery at Carolinas Medical Center and surgeon at Carolina Neurosurgery & Spine Associates, has his pulse on the developmental technologies in spine biologics and motion-preservation technology. He is currently participating in three clinical trials examining less invasive biologic disc repair as well as artificial disc replacements that improve on traditional open procedures in both clinical quality and cost.
"The way spine surgery developed was backwards; they developed the most invasive procedure first, that's the fusion procedure, and the less invasive treatments are still coming down the pipe," he says. "The fusion procedures are a big operation done under general anesthesia and the patient has to stay in the hospital for multiple days. Now we're working toward less invasive procedures that preserve the anatomy and allow patients to go home the same day."
There is great potential for both innovations, depending on how far along the patient is with degenerative disc disease.
Biologic disc repair
Currently, surgeons have nonsurgical treatment options for patients in the beginning stages of DDD and fusion for patients at the end stages, but not much in between. That could change over the next few years, depending on the outcome of clinical studies examining disc repair.
"With biologic disc repair, you will see the potential for less intensive treatment, lower cost and less recovery time for a more patient-friendly, outpatient procedure," says Dr. Coric. "It's really akin to an epidural steroid injection, but here you have the potential for repair as opposed to just the anti-inflammatory effect."
Dr. Coric and his team are involved in two studies with disc regeneration injections: the Mesoblast and ISTO Technologies' NuQu clinical trials. They are preparing for Phase III of the Mesoblast study that will compare Mesoblast stem cell injection to saline injections. The previous Phase II clinical trial showed the Mesoblast injection is most effective with 6 million cells per cc of injection as opposed to 18 million cells, so they'll use 6 million cells per cc in Phase III.
The NuQu injectable juvenile cartilage disc repair has completed Phase II, and researchers are waiting until they hit the two-year follow-up mark with their current patients before moving on to Phase III, which could start later this year.
"These investigational treatments offer the potential to treat patients with DDD in a minimally invasive outpatient fashion," says Dr. Coric. "Using these biologics, we're able to perform the injection under local anesthesia. It takes about five to 10 minutes to complete the procedure, and the injection is only about 30 to 45 seconds long. It doesn't involve a major procedure and potentially offers the hope to repair the disc as opposed to obliterate it with fusion or disc replacement."
The FDA hasn't yet approved any biologic disc repair treatments, but both the Mesoblast and NuQu trials are on their way. A third company, Discgenics, is also working on a biologic treatment for disc repair and could go to the human trials next year. The Discgenics procedure includes active disc cells that are cultured and injected into the disc space.
"There are several regenerative procedures moving through the process and it's exciting because it's a minimally invasive way to repair the disc," says Dr. Coric. "But at the end of the day, this is another tool that surgeons can incorporate into their practices. Like anything else, it's about patient selection. We can work with patients early on with isolated one-level disc disease and treat them before they become chronic narcotics users. It's a niche that needs to be filled, but it's not a cure-all for back pain so surgeons still need to be selective."
Artificial disc replacement
Biologic injections are one avenue to meeting cost and quality goals; cervical disc replacement is another for the right patients.
"With cervical disc replacement, everyone tries to compare it to fusion but they are really different procedures for different patients," says Dr. Coric. "It allows you to treat a younger, more active patient population who present with more isolated, one- or two-level cervical disc disease."
There are currently seven FDA approvals for cervical artificial discs and new generations of technology will soon become available on the market. The procedure gained a Category I CPT code for one-level cervical disc replacement earlier this year and more surgeons are adopting it. Dr. Coric and his team are actively involved in studying the M6 disc from Spinal Kinetics; it's one of the most popular discs in Europe and now could expand into the United States.
"It's a next-generation disc with a compressibility component for better quality motion," says Dr. Coric. "There are parts of the disc that mimic the annulus and nucleus, so there is more sophistication of the devices."
There are also new discs, such as the Simplify Disc, with PEEK and ceramic components, that could come to trial this year that would have advantages for imaging in patients with the disc. "The technology is evolving and more patients want artificial discs as opposed to fusion, if possible," he says.
Spinal cord injury
Spinal cord injury treatment is also evolving into the biologics realm. Dr. Coric and his team are involved in the InVivo clinical trial for the Neuro-Spinal Scaffold for patients with traumatic spinal cord injury. Currently, surgeons are limited in treating spinal cord injury patients, but with the new InVivo technology surgeons open the dura and insert the implant in the substance of the damaged spinal cord. The implant is a resorbable polymer to provide biomechanical support for the cord.
Only three patients have undergone the surgery so far with between six and nine month follow up. However, two of the three patients (66 percent) improved their AIS grade by one month after surgery, typically only 5 to 6 percent of patients with complete spinal cord injury improve an AIS grade by 1 month post-injury.
"It's exciting because there is this huge area of catastrophic injuries and very little we can do besides stabilization," says Dr. Coric. "But now we can implant the polymer into the substance of the spinal cord to provide some mechanical support. It's early on, but we're doing the human trials focused on trying to positively affect the actual site of spinal cord injury. These results are preliminary, but you can envision somewhere down the line combining the biological treatment with mechanical treatment for a better solution."