SI-Bone Showcases Sacroiliac Implant at AAOS

SI-Bone Inc. was spun off of Inbone Technologies when Wright Medical bought the company in 2008. Since then, the company has developed an implant specifically aimed at the treatment of the sacroiliac (SI) joint, the joint in the bony pelvis between the sacrum and the ilium of the pelvis, which are joined by strong ligaments. In humans, the sacrum supports the spine and is supported in turn by an ilium on each side. The iFuse Implant System (pictured left) is designed to provide a less-invasive alternative to traditional SI joint fixation/fusion surgery, and uses the same titanium implant technology that was used in the Endo-Fuse system, the system developed and marketed by Inbone Technologies.

The San Jose, Calif.-based company will be featuring its technology at this year’s 80th annual conference of the American Academy of Orthopaedic Surgeons (AAOS). “We are looking forward to the opportunity to educate this diverse group of orthopedic specialists on the diagnosis and treatment of SI joint disorders,” said Jeffrey Dunn, president and CEO of SI-Bone.

The iFuse received original 510(k) clearance in November 2008 from the U.S. Food and Drug Administration (FDA) for fracture fixation of long bones and large bone fragments of the pelvis for conditions including sacroiliac joint disruptions and degenerative sacroiliitis (inflammation of the SI joint), and an additional clearance in April 2011 for SI joint fusion for conditions including SI joint disruptions and degenerative sacroiliitis. The CE mark for European commercialization was obtained in November 2010.

Data from a 1987 article in Clinical Orthopedics identified the SI joint as the source of pain in 20 percent of low back pain patients. In 2011, Pain Medicine ran a study identifying the SI joint as the pain generator in 40 to 61 percent of post-lumbar fusion patients, or so-called “failed back surgery patients.” Initial treatment options for patients with SI joint disorders typically involve non-surgical management and, when non-surgical treatment of the SI joint fails, surgical treatments such as the iFuse may provide a viable option.

The SI joint tends to be under-diagnosed as the source for lower back pain, as lower back pain is so common and the causes so wide. According to the National Institute of Neurological Disorders and Stroke (a division of the National Institutes of Health), “Americans spend at least $50 billion each year on low back pain.”

“Our goal for attending the AAOS meeting this year is to raise awareness among the various orthopedic specialists…who currently manage these patients and educate them on the diagnosis and treatment of patients who suffer from SI joint disorders,” SI-Bone spokesperson Greg Desfor told Orthopedic Design & Technology.

The iFuse procedure, a minimally invasive surgery (MIS), uses a small incision for delivery and implantation of titanium implants. The implants are coated with a porous, titanium plasma spray that acts as an interference surface, designed to help decrease implant motion and provide immediate fixation and long term fusion. According to SI-Bone, the advantage of the implants over conventional screws used to fix bony structures is that the implants are thicker with a more sophisticated metallurgy.

Desfor explained that “the implants are placed through an interference fit across the ilium and into the sacrum, and the triangular profile minimizes rotation to achieve stabilization and fusion of the SI joint.” An interference fit refers to a method of attachment where two parts are pressed together. There are no other clips or means of fastening involved.

December last year saw the 5,000th patient treated by the iFuse implant, and also the first ever inclusion of the device in a peer-reviewed journal article. The article, titled “Sacroiliac Joint Arthrodesis—MIS Technique with Titanium Implants: Report of the First 50 Patients and Outcomes” is a retrospective study of the first 50 consecutive patients treated by a single surgeon in a single center. Patients were evaluated for pain and functional outcomes and showed early and sustained statistically significant improvement at all post-operative time points. Complication rates were low and after an average of 40 months, more than 80 percent of patients report that they would have the same surgery again.

Editor’s note: SI-Bone will be exhibiting at booth 655 during AAOS at the McCormick Place convention center.

Photo courtesy of Genesys Healthcare.