Sacroiliac joint fusions are a relatively new area for spine surgeons to treat, and a few different companies are developing technology to treat SI joint dysfunction through minimally invasive procedures.
In the past, many training programs didn't focus on SI joint dysfunction and patients with SI joint pain underwent other types of spine surgeries. Data shows that around one-third of low back pain or hip pain patients have an SI joint issue. Now, it's clear the SI joint is the pain generator for many patients and as a result technology is evolving to address the issue.
Initially, SI fusions involved a complex open anterior surgery that required several surgeons and multiple hours to perform. Today the SI joint can be accessed with minimally invasive techniques.
"The first MIS technologies to be developed for treatment of sacroiliac dysfunction were metal implants that transversed the joint," says Gowriharan "Ty" Thaiyananthan, MD, founder of BASIC Spine in Newport Beach, Calif. "One of the questions that arose from this technology is whether surgeons were achieving a true fusion across the joint."
Second generation technology was developed to allow surgeons to access the SI joint through a MIS approach and to given them the ability to decorticate the joint and place bone graft in the surgical site to encourage a true fusion.
The two major players in the MIS SI joint fusion field today are SI-BONE and Zyga Technologies.
"There were a host of other companies that came out with similar products and variations of these two techniques," says Dr. Thaiyananthan. "The real question is: What is the best way to treat this?"
Both techniques demonstrate the benefits of less invasive procedures:
• Less blood loss
• Patients can often return home the same day
• Less muscle disruption
• Lower pain scores following surgery
The challenge with treating the SI joint has also been that many if not most surgeons weren't trained on the technology during residency or fellowship. This was problem was compounded by the fact that many payers initially considered the procedure experimental resulting in poor to no reimbursements.
"There is enough data behind the procedure to justify that it is an effective treatment to a prevalent spine problem," says Dr. Thaiyananthan. "As insurance carriers and patients acknowledge SI fusion as an effective treatment and as more surgeons get trained on this procedure we will see an increase in the number of SI fusions."
The procedure received a CPT Category 1 code in January 2015 and studies showing minimally invasive SI fusion's effectiveness have been published in peer-reviewed literature. But not all surgeons are performing it.
"One of the hesitations for physicians to picking up and performing these procedures is that they weren't trained on it in school and the anatomy can be a little challenging," says Dr. Thaiyananthan. "It definitely takes practice on cadavers and a good understanding of the three-dimensional anatomy of the SI joint."
The procedure also has a learning curve in the operating room. Initially, minimally invasive SI joint fusions can take 60 minutes to 90 minutes. For an experienced surgeon, it's relatively common to finish the procedure in 30 minutes.
Additionally, strong data on long-term outcomes is still being developed.
"The key thing right now with this technology is developing the data behind it," says Dr. Thaiyananthan. "We need more prospective studies. There is a difference between the SI joint fusion systems that are out there and I believe the longevity of the surgical results which hinge on whether these systems can create a true fusion across the joint and in turn provide a long term solution to patients with SI dysfunction."
There is a large population who could benefit from minimally invasive SI joint fusion and the technology is growing. "The market will drive evolution of the SI fusion technologies," says Dr. Thaiyananthan. "As patient's become more educated on the fact that upwards of 30 percent of back pain may actually be SI pain they will look for surgeons that can treat this condition. Surgeons will demand SI fusion technologies backed by data that deliver lasting solutions for their patients."