Diane Lee is a physiotherapist from Delta, British Columbia, who specialises in pelvic dysfunction. Her reputation is renowned worldwide through her many published works. She is a member of the international scientific committee for the Interdisciplinary World Congress on Low Back and Pelvic Pain and is on the editorial board of the journals “Manual Therapy” and “Manual and Manipulative Therapy”. She is the author of four acclaimed books on Pelvic dysfunction as well as videos for therapists and patients.
There is much debate on movement at the SacroIliac Joint. Could you explain how much movement takes place and why?
“Two independent studies have shown that the sacroiliac joint is capable of a small amount of movement (1-4 degrees of angular motion) and that this motion persists throughout life. It is an essential component for shock absorption to prevent impact forces during walking from reaching the spine. For load to be properly transferred through the pelvis it is essential that this motion is controlled, and this control comes from proper activation of the deep stabilizing muscles of the low back and pelvis and proper function of the ligaments of the sacroiliac joint.”
Jacob H A C, Kissling R O, 1995, The mobility of the sacroiliac joints in healthy volunteers between 20 and 50 years of age. Clinical Biomechanics 10(7): 352-361.
Sturesson B, Selvik G, Uden A, 1989, Movements of the sacroiliac joints a roentgen stereophotogrammetric analysis. Spine 14 (2): 162 165.
Vleeming A, Wingerden J P van, Dijkstra P F, Stoeckart R, Snijders C J, Stijnen T, 1992, Mobility in the SI-joints in old people: a kinematic and radiologic study. Clinical Biomechanics 7: 170-176.
The theory you co-developed with Andry Vleeming, of “An integrated model of joint function”, has been widely accepted as a brilliant illustration of how joints work and become dysfunctional. Could you briefly explain the four components for our readers?
“First of all, thank you for your kind comment regarding our model. This model centres around function as opposed to pain. There is a lecture on my website www.dianelee.ca, called Understanding Your Back Pain, which addresses the difference between functional diagnoses and structural diagnoses. The Integrated Model of Function (Lee & Vleeming) addresses 4 separate components which are essential for optimal function. The primary functional requirement of the pelvis is to transfer load between the trunk and the lower extremities. The first component is called “form closure”. This term was coined by Andry Vleeming and Chris Snijders.”
Vleeming A, Stoeckart R, Volkers A C W, Snijders C J 1990a Relation between form and function in the sacroiliac joint. 1: Clinical anatomical aspects. Spine 15(2): 130-132.
Vleeming A, Volkers A C W, Snijders C J, Stoeckart R 1990b Relation between form and function in the sacroiliac joint. 2: Biomechanical aspects. Spine 15(2): 133-136.
“Form closure addresses how a joint’s shape and its ligaments contribute to stability. In other words, how does the integrity of the joint help to prevent shearing and excessive translation between the two joint surfaces when under load. At the SIJ, vertical forces must be controlled during walking, sitting and prolonged standing while forward and backward forces (anteroposterior translation) must be controlled during forward bending activities such as vacuuming, making beds or putting on your shoes.”
“The second component of our model is called Force closure – another term coined by Vleeming and Snijders. This component addresses how and what extra forces are necessary to control translation between two joint surfaces when load is applied. The necessary force for controlling shear at the SIJ is compression. Compression is provided by the deep stabilizing muscles of the low back and pelvis which are transversus abdominis, multifidus and the pelvic floor. Collectively, these muscles have been referred to as the core muscles.”
“The third component of our model is motor control. Motor control addresses the nervous system and is about the co-ordination or co-activation of these deep stabilizers. One of the world’s leading research teams from the University of Queensland (Richardson, Jull, Hodges & Hides) have investigated the timing of these muscles in low back pain patients. They found that normally, these deep stabilizers should contract before load reaches the low back and pelvis so as to prepare the system for the impending force. They found that in dysfunction, there is a timing delay or absence of contraction of these muscles and consequently the system is not stabilized prior to loading. They also found that recovery is not spontaneous, in other words – the pain may go away but the dysfunction persists.”
Hides J A, Stokes M J, Saide M, Jull G A, Cooper D H 1994 Evidence of lumbar multifidus muscles wasting ipsilateral to symptoms in patients with acute/subacute low back pain. Spine 19(2): 165-177.
Hides J A, Richardson C A, Jull G A 1996 Multifidus recovery is not automatic following resolution of acute first episode low back pain. Spine 21(23): 2763-2769.
Hodges P W, Richardson C A 1996 Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of transversus abdominis. Spine 21(22): 2640-2650.
“Recently, Richardson investigated how these muscles impact the SIJ using the Echo Doppler [a diagnostic ultrasound device, which can show if specific muscles are contracting]. They were able to show that when the transversus abdominis and multifidus co-contract, the stiffness of the SIJ increases thereby proving that these muscles are essential for compressing the SIJ and stabilizing the joint under load (force closure – 2nd component). It is critical that this compression occurs at just the right time (motor control – 3rd component).”
Richardson C A, Snijders C J, Hides J A, Damen L, Pas M S, Storm J 2002 The relationship between the transversely oriented abdominal muscles, sacroiliac joint mechanics and low back pain. Spine 27(4):399-405.
“The fourth component of our model addresses the role that our emotional state has on our ability to motor control effectively. It is well known that stress, anxiety, fear and pain all impact our emotional state and we now know that this state impacts our ability to motor control. Several studies are currently underway to specifically look at the impact of attention deficit, stress, fear etc on the core muscles. Holstege has shown that the emotional state is critical to health and recovery since it is through the muscle system that the mind ultimately expresses itself.”
Holstege G, Bandler R, Saper C B 1996 The emotional motor system. Elsevier Science.
“In summary, what we are trying to express through the Integrated Model of Function is that there are many components to consider in a functional model and each must be addressed for recovery to be long-standing.”
Joint stability is important for optimal function. Do you feel that once the patient with pelvic dysfunction has been taught stabilisation exercises they are able to maintain healthy joint function themselves?
“Effective force closure is the goal of these stabilization exercises and yes, with proper education and individual can maintain healthy joint function.”
Could you briefly explain the mechanism of SI joint dysfunction during pregnancy?
“During pregnancy, the deep abdominal muscles become stretched. If a woman has less form closure and relies on force closure for stability, then she is more vulnerable to developing pelvic pain during her pregnancy. In addition, a hormone called relaxin is released at periodic intervals during pregnancy and this hormone has the effect of relaxing the ligaments of not only the SIJ but the body. This contributes to the loss of both form and force closure and again there is a greater vulnerability to shear.”
“During a vaginal delivery, the muscles of the pelvic floor are frequently stretched, cut or torn. This further compromises force closure of the pelvis. It is absolutely essential that a postpartum woman address the function of her deep abdominals and pelvic floor if she is to prevent an onset of pelvic and/or low back pain, possible future urinary incontinence and uterine prolapse. For this reason, the program Postpartum Health for Moms (www.dianelee.ca) was developed and I truly believe that all women should take a course like this to learn how to “put their bodies” back together again after having a baby. Prevention is the key! While training these deep muscles a sacroiliac belt (see The COMPRESSOR at www.dianelee.ca or OPTP.com) can help to support the pelvis. The COMPRESSOR was designed to allow an individual to specify where and how much compression is applied to the pelvis. It is a training tool and not meant to replace a proper exercise program.”
What are your thoughts on the role of corticosteroid or local anaesthetic injections for patients with SI joint dysfunction?
“Intra-articular injections of corticosteriods are useful when the SIJ is acutely inflamed. An inflamed SIJ is difficult to stabilize since further compression increases the pain. A local anaesthetic merely confirms the diagnosis that the SIJ is a pain generator but in my opinion, does little to answer the question ‘Why is the SIJ painful?’ These injections play a role in the treatment of SIJ pain but are not functional treatments and a patient with SIJ dysfunction should be treated with a functional approach. Sometimes, it is necessary to address pain in order to move forward in the rehabilitation of function. When compression of the SIJ increases pain – a consideration must be given as to the possibility of an intra-articular synovitis (truly inflamed SIJ). This is the main indication for cortictosteroid injection.”