Published February 2020
Author, Rob Orr
Sometimes it can be confusing establishing whether it is a disc of the lumbar spine or the sacroiliac joint (SIJ) causing the client’s unilateral lower back pain, SIJ pain and associated buttock pain. What about when the client tells you that they also have referred pain into the groin and anterior thigh region, and on testing displays major losses in lumbar range of motion as well? There will of course be times where the client only presents with lower back pain and major losses of motion, or pain directly over the SIJ and nowhere else with major losses of motion.
Is it a lumbar disc? Is it the SIJ? Could it be a combination? Or is it a sinister pathology presenting as a mechanical source of pain? Sinister spinal pathologies (red flags) and psychosocial matters (yellow flags) are out of the scope of this article as it will focus on acute mechanical pain. ‘Serious spinal pathology presents in <1.8% of the population.’1 Even though this is a low statistic it is always essential that you clear ‘red flags’ by taking a thorough history! It is also important to clear yellow flags, especially if the pain has been chronic. The hip joint as a differential diagnosis hasn’t been included here as this article’s main focus is the lumbar spine and SIJ.
Theory
The focus of this article is to help the clinician establish whether the client’s acute pain and major losses of motion are mechanical in nature, and whether they are being produced by a lumbar disc or the SIJ.
An evidence-based and scientific approach will be applied in the form of the McKenzie Method (2) (repeated movement of the spine in a specific direction) to help the clinician to rule in/out a lumbar disc derangement (joint obstruction; also known as a posterior disc bulge, posterior lateral disc bulge, disc prolapse, disc protrusion or slipped disc). ‘Using the McKenzie system assessment for discogenic pain had a sensitivity of 94 per cent and specificity of 82 per cent.’(1) Kappa values measuring the reliability of the McKenzie Method when applying this assessment technique to the lumbar spine were measured at 0.70 and 0.84 (on a scale of 0.0 to 1.0).(1) Dr Mark Laslett’s protocol for testing the SIJ will also be covered. He found that the McKenzie Method combined with a specific cluster of SIJ provocation tests showed excellent sensitivity and specificity values for the diagnosis of SIJ related pain.(3)
Due to the high prevalence of positive SIJ pain provocation tests in clients with discogenic pain, Laslett used the McKenzie Method to rule in/out lumbar derangement. If the subject’s pain centralised or showed a clear direction preference during the spinal assessment they were eliminated from his study, and once eliminated the diagnostic accuracy of the SIJ pain provocation tests increased significantly.
Let’s quickly address why you should examine the lumbar spine first for any involvement during the physical examination. In 1991, Dr Kuslich et al published a paper on the tissue origin of low back pain involving 193 patients.(4) Each patient had 17 different tissue types in their lower back stimulated for a painful response through blunt force, and electrical stimulation. The most common tissue type that caused pain was the disc, and to be precise, it was the outer layer (annulus fibrosis) of the disc. Always clear the spine!
Note that the disc can be its own entity of local pain and can refer to multiple sites with no spinal nerve-root involvement. If there is associated pain below the knee it is more likely that the spinal nerve root is involved.(4) The most common source of a spinal nerve root compression is a bulging disc.
In regards to the SIJ, clients may say that they have been told they have SIJ instability; this is unlikely to be the case as the range of movement of the SIJ is ‘less than four degrees of rotation and up to 1.6mm of translation.’(3) Laslett cited the work of Sturesson, who found that in patients presumed to have an SIJ source of pain, there was no difference in range of motion between symptomatic and asymptomatic sides.(3) There is the exception of course with pregnancy-related SIJ pain, pregnancy-related pelvic girdle pain (PGP), and history of trauma.
When it comes to testing the SIJ, there are certain tests that have poor inter-examiner reliability and lack a reference standard for measuring SIJ dysfunction. So the ‘validity of these tests for this disorder is unknown.’(3) Additionally, asymmetry and fusion are common findings in those without pain. ‘Pain provocation tests have acceptable inter-examiner reliability with an acceptable reference standard.’(3) However, used in isolation they do not (Kappa values for three or more positive tests have proven to be higher than a single positive test). This article will focus on reliable and valid methods of testing the SIJ, and specifically which SIJ tests to combine to increase the sensitivity and specificity of the examination. The McKenzie Method will then be incorporated to rule in the lumbar spine (disc) or help clear the lumbar spine of any involvement.
Subjective examination
On questioning (after ruling out ‘red flags’, including fracture) you should get some clues from the client concerning what position, if any, makes them better. For example, better standing (extension) and walking (extension), worse sitting (flexion) and bending forward (flexion). Or is the client worse standing and walking, and better sitting. Even though this is only the start of the investigation these clues are important because your client is telling you what position makes them better!
Objective examination
The first part of a physical examination will consist of a postural check looking for any signs of a lateral shift, a lack of lumbar lordosis, or a kyphotic deformity of the lumbar spine.
The second part of the examination will focus on the client’s lumbar spine, looking at range of motion and associated pain/s.
The third part of the examination will focus on the SIJ. Four specific SIJ pain provocation tests will be applied consecutively:
(1) Iliac Distraction also known as the Gapping Test
(2) Posterior Shear also known as Posterior Thrust Test
(3) Side lying Compression Test
(4) Gaenslen’s Test also known as Pelvic Torsion Test.
If the client is positive with three out of the four SIJ pain provocation tests in the absence of the client’s pain centralising (distal pain moving towards the midline of the spine), the validity of the tests markedly increases.(3)
The fourth part of the examination is to apply the McKenzie Method, consisting of repeated movements in a specific direction aiming to get to end range. If the client’s pain does not centralise when applying the McKenzie Method, the probability of having SIJ pain increases.(3)
Now remember this is only the case if the client’s pain and symptoms do not centralise. To clarify, three out of four SIJ tests need to be positive, meaning that the client’s pain is reproduced during the examination. In conjunction with this the McKenzie Method needs to be included to rule out a lumbar derangement.(3)
The fifth and final part of the examination is re-testing the SIJ and lumbar spine with the same tests to establish if the condition is the same, better or worse after the McKenzie assessment. Prior to re-testing, ask the patient if their location of pain has moved towards the midline (centralising)? Has the pain disappeared from one area and gone to another? These are all important clues. When re-testing the client’s lumbar spine range of motion is there still pain associated with those movements? Can the client move further into range comfortably? When re-testing the SIJ are all three or four tests still positive? If unsure, repeat procedures two to five again.
If the client’s pain starts to centralise during the McKenzie Method, it is more likely that the pain is discogenic in nature and not the SIJ. If this is the case, you should also notice a significant improvement in lumbar range of motion. ‘Centralisation can be reliably evaluated and has been shown to be a significant prognostic factor; its presence is associated with good outcomes.’(1)
Discussion
The history of the client combined with the above objective examination should help you clinically assess: (1) red and yellow flags; (2) which structures are more likely involved; (3) which structures are less likely involved; (4) whether there is an injury leading to chemical sensitivity in the form of inflammation; (5) if the pain is mechanical due to the tissue being structurally compromised; (6) if there is evidence of a derangement (joint obstruction); (7) if the pain is non-mechanical in origin.
So in the history if the client displays either a sustained position or a repeated movement that rapidly reduces their pain, it is more likely a derangement of a lumbar disc or SIJ. Something is obstructing the joint leading to pain. If the pain is constant, it’s more likely that the pain is chemically driven. If the pain is intermittent, it’s more likely that the pain is being driven by mechanical sensitivity of that specific tissue/s. If the client displays a significant improvement in range of motion as well, this is more supporting evidence of a derangement. If the client’s pain shows signs of centralising, this is further evidence that a lumbar disc is involved.
Now if the client’s pain rapidly subsides with either repeated hip flexion (posterior torsion of the SIJ) or repeated hip extension (anterior torsion of the SIJ) without signs of centralising, it’s more likely that the SIJ has been deranged. This should also be supported by a significant improvement in lumbar range of motion on retesting. So once you have ruled out the lumbar spine it should be a lot clearer if the SIJ is involved. These are all clues that will help you with your working diagnosis supported by scientific evidence. Also please remember that the examination is not just about ruling in which structures are involved, but most importantly which structures are not involved.
Summary
If your client displays a rapid improvement in their symptoms with a sustained position or a repeated movement into a specific direction, it is more likely that something is obstructing (deranging) the joint leading to pain. Also, if the client’s symptoms centralise this is even more supporting evidence that a derangement (disc bulge) of the lumbar spine is more likely.
If the client’s symptoms rapidly improve with unilateral repeated movements of the hip with no signs of centralising, it is more likely to be a derangement of the SIJ.
It’s not always this straightforward, and you will get some complex cases, but this approach should help guide you through your investigation.
CASE STUDY
I would like to finish with an informal case study involving myself to give you an example of how this system works. On Sunday 2 February 2020 during a heavy weight training session I experienced sharp and dull left-sided lower back pain, pain over the sacroiliac region, sharp catching pain when getting up or down, left groin pain, and shooting pain into the left anterior thigh. The pain was constant and was rated 8/10 on the pain scale, and I was unable to walk or stand for two days due to the pain. No pain or altered sensation was felt below the knee at any point. Was it a lumbar disc or SIJ?
On day one of the injury I only felt a reduction in pain with sitting in flexion, and then a further reduction in my pain when placing my hip in maximal flexion. The 8/10 pain was rapidly reduced to 2/10 then 0/10 within 10 minutes of injuring myself, while in this position. With this rapid and significant reduction of pain I thought it was more likely to be a derangement of the lumbar spine or the SIJ. The chance of a serious spinal pathology like a fracture was unlikely due to these sudden changes for the better. It was less likely to be inflammation due to tissue damage because my constant pain changed to intermittent pain then completely disappeared as soon as I found a specific position.
On day two of the injury I used the McKenzie Method to help classify my condition so I could start my rehabilitation as soon as possible! I couldn’t use Laslett’s SIJ testing protocol as I was on my own, but I knew I could use the McKenzie Method to rule in/out other conditions. The clues at this point: I was worse with standing (extension) and walking (extension), and better with sitting (flexion) and my hip placed in end range flexion. Another important clue was that my pain didn’t centralise, it reduced, then just disappeared within 10 minutes.
So the evidence was strongly indicating that my SIJ was responding to a direction preference for flexion. The more ideal term for the SIJ would be posterior torsion, but let’s refer to this as flexion to keep it simple. From the evidence presented I proceeded with repeated supine bilateral hip flexion x 10–15.
On re-testing my pain had reduced and my range of motion also improved, not significantly but there was an improvement. This indicated to me that I was heading in the right direction. I then proceeded with supine unilateral hip flexion x 10–15 aiming to get to end range. During the last couple of repetitions the pain was minimal to none, and I was able to get my hip to end range. This made me believe it was more likely to be a derangement of my SIJ that was displaying a direction preference for repeated hip flexion.
My clinical reasoning for this was
(1) Repeated supine bilateral hip flexion reduced my pain and increased my mobility, but this was a minimal change (also I did not feel my pain centralise)
(2) Repeated supine unilateral hip flexion that involves more motion of the SIJ into flexion caused a rapid and significant reduction in pain, and a significant increase in lumbar range of motion.
(3) I was also able to stand and walk for a longer period of time with minimal pain.
So for the next three to four days I did 10–15 repetitions every 1–2 hours.
Within four days of the injury I was back to boxing, within six days I was back to modified weight training. Within eight days of the injury I was back to lifting heavy weights over my head again, including Olympic lifting!
This is an example of how efficient the McKenzie Method is in helping the therapist to establish where the main pain is coming from, and how fast I was able to get back into heavy lifting and training following the McKenzie protocol. This is a pretty good result after not being able to walk or stand for two days.
References
1. McKenzie R, May S. The Lumbar Spine Mechanical Diagnosis & Therapy volume one. Spinal publications Waikanae, New Zealand; 2004.
2. McKenzie R, May S. The Lumbar Spine Mechanical Diagnosis & Therapy volume two. Spinal publications Waikanae, New Zealand; 2004.
3. Laslett M. Evidence-Based Diagnosis and Treatment of the Painful Sacroiliac Joint. Journal Manual Therapy. 2008; 16:3:142-152.
4. Kuslich et al. The Tissue Origin of Low Back Pain and Sciatica: A report of Pain Response to Tissue Stimulation During Operations on the Lumbar Spine Using Local Anesthesia. Orthopedic Clinics of North America. 1991, April;22(2):181-7.
Bibliography
Sturesson B 1999, Load and Movement of the Sacroiliac Joint, PhD thesis, Lund University, Malmo, Sweden.
Laslett M, Williams M 1994, The Reliability of Selected Pain Provocation Tests for Sacroiliac Joint Pathology. Spine 1994;19:1243-49.
Laslett M, Young SB, April CN, McDonald B 2003, Diagnosing Painful Sacroiliac Joints: A Validity Study of a McKenzie Evaluation and Sacroiliac Joint Provocation tests. Australia Journal Physiotherapy. 2003;49:89-97.
Aina A, May S, Clare H 2004, The Centralization Phenomenon of Spinal Symptoms: A Systematic Review. Man Ther. 2004;9:134-143.
Donelson R, April C, Medcalf R, Grant W 1997, A Prospective Study of Centralization of Lumbar and Referred Pan: A Predictor of Symptomatic Discs and Annular Competence. Spine. 1997;22:1115-1122.
Donelson R, Grant W, Kamps C, Medcalf R Spine 1991, Vol 16. Pain Responce to Sagittal End Range Spine Motion. A Multi-centered, Prospective, Randomized Trial; pp.S206-S212.
Wetzel FT, Donelson R 2003, The Role of Repeated End-Range/Pain Response Assessment in the Management of Symptomatic Lumbar Discs. Sopine J. 2003;3:146-154.
Dreyfuss P, Dryer S, Griffin J, Hoffman J, Walsh N 1994, Positive Sacroiliac Screening Tests in Asymptomatic Adults. Spine. 1994;19:1138-1143.
Sturesson B, Selvik G, Uden A 1989, Movements of the Sacroiliac Joints: A Roentgnen Strereophotogrammetric Analysis. Spine. 1989;14:162-165.
McKenzie RA 1981, The Lumbar Spine: Mechanical Diagnosis and Therapy. Waikanae, NZ: Spinal Publications Ltd; 1981.
May S, Aina A 2012, Centralisation and Direction Preference: A Systematic Review, Manual Therapy. Doi. 10.1016/j.math.2012.05.003.
About the Author
Rob Orr, Cred. Mechanical Diagnostic Therapy, Post. Grad. MSK, Adv. Dip. Myotherapy, Dip. App. Sports Studies, Cert IV Personal Training.
Rob is a Credentialed McKenzie Therapist & Clinical Myotherapist with 18 years clinical experience in private practice specializing in the diagnostics of musculoskeletal pain including sports injuries, spinal pain, disc pain and sciatica.
Rob also lectures at Victoria University and runs private workshops for other allied health professionals around Australia. If you would like to make an appointment to see Rob or have a query, please click this link