Bengt Sturesson, of the Department of Orthopaedics, Ängelholm Hospital, Sweden, talks to Spinal Surgery News about the role of the sacroiliac joint and how pain can develop and be diagnosed inside the pelvic ring
Where is the SI joint?
The sacroiliac (SI) joint is located inside the pelvic ring and has, to some extent, been a hidden or forgotten link between the spine and the hip. The mission for the SI joint is to transfer load and be part of force transmission from the spine to the hip.
What is the role of the SI joint?
The SI joint is a joint with cartilage and joint capsule. The movements are low but well described. The movements are related to the force transmission and the position of the body. In standing there is a forward rotation of the sacrum related to the ilia and in the supine position a posterior rotation. These movements are 1.2 to 1.4 degrees. There is no evidence for hypermobility but the variation between individuals shows a normal distributed pattern. Evidence shows a reciprocal pattern in walking and reduced movement when compression is achieved with muscle power or external fixation.
How does the SI joint contribute to low back pain?
Like all joints the SI joint is exposed to trauma, degenerative arthritis as well as inflammatory arthritis. The prevalence is not fully known; however, we know that degeneration starts already in the third decade and increases with age.
What makes it start hurting?
Pain is more complex to understand than degeneration. Some individuals report pain because of the joint arthritis and some not. To that extent, the SI joint can be compared with other joints. Either the movement over a degenerated cartilage or so-called end-position pain can facilitate the pain.
What are the most common symptoms of SI joint pain?
The pain is located in the gluteal area with a pain referral most often to the posterior thigh but sometimes also to the lower leg and groin. The SI joint is innervated with nerve branches from L4 to S2. As with all degenerative diseases there is a variation of severity; the pain is experienced in sitting, standing, walking and lying on the back.
Who can have SI joint pain?
Anyone can develop SI joint pain due to degeneration. Persistent pain after pregnancy, post-traumatic pain after both low- and high-energy traumas, arthritis linked to inflammatory disorders, and degenerative arthritis – with or without previous spinal surgery – are the most common aetiologies.
What steps can be taken to diagnose SI joint pain?
Patients with back pain below L5 should be suspected of having an SI joint disorder. Persisting pain after pregnancy, trauma to the pelvic ring with or without fracture and previous spinal surgery should be further assessed. Specific clinical tests for the SI joint are well described in European guidelines for pelvic girdle pain. If three out of five tests are positive, the diagnosis has to be confirmed with a sacroiliac joint block.
What are the treatment options?
It has to be emphasised that there is a big variation in severity of SI joint pain. The treatment has to be focused on stability of the joint. Physical exercise programmes have to be individually tailored. Core muscle training with specific emphasis on the transverse and oblique abdominals and gluteals are essential for a good outcome with non-surgical treatment. Painkillers have to be regarded as adjuvants. Injections have a place in the treatments only with patients with inflammatory diseases. Passive treatments such as TNS have a place during pregnancy but in all other situations treatment will focus on active muscle training; if this fails, surgical treatment can be discussed but not before six months of good exercise training.
What’s your personal experience of treating SI joint pain using surgery?
Personally, I have more than 25 years of experience in surgical treatment. For the first 20 years I performed open fusion using the Smith-Peterson approach, with either an external Hoffman-Slätis frame fixation or an iliosacral screw fixation. The surgery was demanding both for the surgeon and the patient. The postoperative morbidity was also significant.
In 2010 I found iFuse. From my previous biomechanical studies and the technique achieving immediate stability, I clearly saw the potentials of this product. I performed my first surgery in 2011 and the outcome was great. Five years later we have performed around 200 procedures. In 2012 we conducted a pilot study; the outcome was rewarding and we are about to start a European multi-centre study.
iFuse is a very unique product and currently more than 20,000 procedures have been performed and multiple clinical studies have been published.
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