Surgeons Discuss Minimally Invasive Surgical Sacroiliac (SI) Joint Fusion with the iFuse Implant System®

Doctors do not always look at the sacroiliac joint as a source of low back problems. In the below interviews, Dr. Steven Garfin* and Dr. Leonard Rudolf+. They discuss the need to educate patients and doctors about the SI joint being a relatively common cause of low back problems and answer questions regarding the issues affecting the sacroiliac joint. Once the sacroiliac joint is identified as a possible source, what options does the patient have and when does minimally invasive surgery with iFuse; make sense? Read the interviews below to learn more about diagnosing and treating the sacroiliac joint.

Steven Garfin, MD Image
Steven Garfin, MD
Orthopedic Surgeon
San Diego, California


Dr. Garfin is an orthopaedic surgeon specializing in adult spine disorders. He trains both orthopaedic surgeons and neurosurgeons in spine care at UC San Diego. He has been involved in a number of clinical trials related to new techniques to treat spinal deformities and injuries. In this interview, Dr. Garfin shares his experience with diagnosing and treating SI joint problems.

Question: If a patient is experiencing pain in the lower back, how important is it to look at the sacroiliac (SI) joint as a pain generator?
Answer: As physicians we are unable to make a specific diagnosis in 80-90% of patients who complain of low back pain. It is important to evaluate all possible causes of low back pain to help direct more specific treatments. The SI joint can and does cause low back pain and should be included in the differential diagnostic work-up.

Question: How often do patients you see with low back pain have a problem with their SI joints?
Answer: It is only recently that I have paid attention to the SI joint as a potential cause of low back pain (LBP). That is because of increasing awareness in the literature of multiple pain generators being responsible for LBP. Published studies have shown that up to 25% of low back pain complaints can be related to the SI joint. This underscores the need for all clinicians to be aware of non-spinal pain generators and to pursue alternative differential diagnoses.

Question: Who is most at risk for sacroiliac joint problems?
Answer: Anyone can develop SI joint problems with or without trauma. However, perhaps the highest risks of patients with symptoms originating from the SI joint are during/following pregnancy, following motor vehicle accidents or other high impact accidents or falls. Additionally, patients with specific types of sacroilitis and major pelvic disruptive trauma can have persistent SI joint problems, not responsive to normal medical means.

Question: Is it difficult to diagnose sacroiliac joint disorders?
Answer: Yes, it may be difficult to diagnose SI joint disorders. Imaging studies (X-rays, MRI, CT) are occasionally, but not always, helpful. There are no specific imaging studies (unless there is obvious disruption of the joint) that reliably help. The physical exam is not specific. The 'gold standard' is image-guided injection into the SI joint.

Question: If a patient were to present in your office today with sacroiliac joint problems, how would you treat them?
Answer: The standard treatment is non-steroidal anti-inflammatory medications, physical therapy, and time. If those are not effective then I would consider SI joint injections (both for diagnosis and potentially treatment). If that fails (therapeutic injections into the joint are only effective approximately 70% of the time), I would consider SI joint fusion using the iFuse Implant System.

Leonard Rudolf, MD Image
Leonard Rudolf, MD
Orthopedic Surgeon
Lebanon, New Hampshire


Doctor Rudolf is an orthopedic spine surgeon who has performed SI joint procedures for over 5 years. He is a spine fellowship trained surgeon in community practice since 1987. He completed his residency in New York, and his spine training at Columbia-Presbyterian Medical Center. In this interview, Dr. Rudolf shares his experience with diagnosing SI joint disorders and treating patients with the iFuse Implant System.

Question: Why is it important to be informed about the sacroiliac (SI) joint and its role in low back pain?
Answer: It’s important for both patients and physicians to be informed because the SI joint has been determined to be one of three key pain generators for patients with low back pain (the hip-spine-SI joint triad). For practitioners to establish a reasonable differential diagnosis of low back pain, they need to be aware of the SI joint as a legitimate pain generator. In this day and age, patients are educated about their health, and we are seeing much more informed decision making and patient directed care. Patients with low back pain need to be aware of the SI joint when they are interacting with their doctor and know what questions to ask. Certain medical professionals with low back pain and diagnostic experience are already aware of SI joint problems, such as pain management physicians, physiatrists, and physical therapists. These specialists are already aware of and treating the SI joint non-invasively. We need heightened awareness among primary care physicians, who are the first line of defense when a patient has low back pain, and among spine surgeons who deal with lumbar spine problems (one of the pain generator triad). The SI joint needs to be on their radar screen, as it has not traditionally been included in the orthopedic/neurosurgery educational curriculum or in spine fellowships.

Question: Which patients do you examine for SI joint problems?
Answer: Any patient that presents with low back pain gets an evaluation of the spine, hip and SI joint (the triad). These three areas of the body are part of a continuum that can cause or contribute to low back pain. The SI joint is not ignored, as it is part of this three-part triad and it can therefore be assessed. The SI joint must be included in the evaluation, as it may be affected. I would not be complete in my differential diagnosis without examining all three.

Question: How do you diagnose the SI joint as a cause or contributor to a patient's low back pain symptoms?
Answer: It is a diagnostic process that is complex and has elements of inclusion and exclusion. All three areas – the lumbar spine, the hip, and the SI joint - are all initially evaluated. As we are able to rule out a certain area or areas, the differential diagnosis gets shorter. Then we can evaluate the SI joint through inclusion. To prove the SI joint is the pain generator, is to do image-guided injections (either fluoroscopic or CT guided) to ensure the needle is in the right place. The patient's response to the injection is the factor most important to ascertain the SI joint as a pain generator. If >75% of the patient’s pain is reduced with one injection, then the SI joint is ruled in.

What we are really talking about here are major paradigm shifts in the way spine surgeons diagnose low back pain. The first paradigm shift is the inclusion of the SI joint in the differential diagnosis of low back pain. The second paradigm shift here is to understand that patients can have more than one pain generator. Identifying the primary and secondary (if applicable) pain generators becomes important and affects treatment. For example, if a patient experiences 50%-75% pain relief from an injection, the SI joint is a secondary pain generator, but if its >75% then the SI joint is primary. This determination impacts both the strategy and sequence of treatment.

Question:If a patient were to present in your office today with SI joint problems, how would you treat him or her?
Answer: If they've not yet had any non-operative care, I would refer them and see how they do; minimally invasive surgery may be offered later if they don’t improve. If a patient has long-standing symptoms and has exhausted non-operative care, and/or if a patient was referred by a pain management physician, who could not improve the patient's condition, then I would suggest the patient consider minimally invasive SI joint surgery.

A significant clinical problem I see is that an otherwise appropriate, well-executed spine fusion surgery can still leave a patient exposed to problems later – whether from a single or multi-level fusion. This is a condition sometimes referred to as adjacent segment disorder. In this type of case the SI joint is negatively impacted after joints are fused higher up in the spine (I would consider this the third paradigm shift). With this situation, a change in spinal mechanics generates a change to the SI joint that may not get better with physical therapy or other conservative care.

Question: In your opinion, how is the iFuse Implant System good for surgeons and their patients?
Answer: iFuse is an MIS treatment option for fusion of the SI joint that is less invasive than open surgery, which is ultimately important to patients. From a surgical point of view, the iFuse procedure is straightforward, simple, and the image-guided design of the implants allows for proper placement.

It is a newer procedure and does require training, which is readily available. Using iFuse requires some change in thinking, as the implants cross the SI joint they create the bridge needed for successful fusion.

Many spine surgeons see their post-lumbar fusion patients with continued pain or with new onset of low back pain. They may work them up for another lumbar spine problem, when they in fact should be addressing the SI joint. In my opinion, the availability of iFuse may help decrease unnecessary additional procedures, such as second or third lumbar spine procedure. This may help control costs overall, and most importantly, may help address the patient’s specific problem.

The iFuse Implant System® is intended for sacroiliac fusion for conditions including sacroiliac joint dysfunction that is a direct result of sacroiliac joint disruption and degenerative sacroiliitis. This includes conditions whose symptoms began during pregnancy or in the peripartum period and have persisted postpartum for more than 6 months. Clinical studies have demonstrated that treatment with the iFuse Implant System improved pain, patient function, and quality of life at 12 months post-implantation. There are potential risks associated with the iFuse Implant System. It may not be appropriate for all patients and all patients may not benefit. For information about the risks, click here.

* Paid consultant of, ownership interest in SI-BONE Inc.

+Paid consultant of, ownership interest in, and conducts clinical research for SI-BONE Inc.

Next Page: Clinical Results
More Resources in the Physicians Center