ASRA Pain Medicine Update

A 62-year-old male without a significant past medical or surgical history presents to the ambulatory clinic complaining of low back pain. The pain has been present for roughly 3 weeks, and it started after a slip on the ice where he fell onto his buttock. He noted mild immediate pain but a gradual worsening since then. He went to an urgent care 1 week after the fall, and an X-ray at that time was negative for fracture. He denies a prior history of low back pain.

1. If the patient described above had pain originating from the sacroiliac joint (SIJ), what typical symptoms would you expect? What symptoms would lead you towards a different pain generator other than the SIJ?

Symptoms of SIJ pain¹ include: 

• Pain is usually immediately over the SIJ just inferior to the posterior superior iliac spine though it can be present in many other locations such as pain in the buttock, low back, leg, or groin.
• The pain can possibly radiate into the groin or lower extremity though not past the knee.
• Pain onset can be gradual or acute.
• The quality of pain is typically described as aching or sharp but rarely described as burning, numbness, or tingling. 
• Pain is largely influenced by positional changes.
• There is often discomfort within associated muscles including the quadratus lumborum, erector spinae, gluteal, and piriformis muscles.

Symptoms that are less likely to be from the SIJ¹ include:

• Neuropathic quality
• Radiation below the knee
• Positive straight leg raise
• Axial low back pain worsened with extension or facet loading
• FABER test positive with pain into the groin
• FADIR test positive with tender to palpation over piriformis
• Present in a dermatomal pattern 
• Tenderness to palpation over the proximal hamstring, coccyx, ischial spine.
  

Note: it is not uncommon for SIJ pain to present concomitantly with other pain pathologies as listed below.

Differential diagnosis: Seronegative spondyloarthropathies, femoro-acetabular pathologies, hamstring tendinopathy, piriformis syndrome, sacral stress fracture, pudendal neuropathy, Ischial bursitis, coccygodynia, lumbosacral referred pain (discogenic, arthropathy, arthritis, radiculopathy)²

2. What proportion of patients have low back pain caused by sacroiliitis?

A. 5%-20%
B. 15%-30%
C. 20%-35%
D. 25%-40%

B. It has been shown that sacroiliitis accounts for roughly 15%-30% of patients with low back pain, making it a very important etiology to rule in or out when evaluating a patient.³

3. The patient above asks what the cause of his SIJ pain is. What are the typical etiologies of SIJ pain?

SIJ pain is caused by a specific inciting event in approximately 40%-50% of cases. This includes falls (such as in this case), motor vehicle accidents, pregnancy, and spinal fusion. Pregnancy is associated with SIJ pain because of anterior weight gain, compensatory postural changes, and hormone induced relaxation of pelvic ligaments. Leg length discrepancy is another common etiology of SIJ pain due to asymmetric distribution of pressure across the SIJ as forces are increased on the longer leg. Repetitive stress may also cause SIJ pain.^4,5

SIJ pain is usually divided into intraarticular and extraarticular etiologies. Intraarticular etiologies include arthritis (osteoarthritis, rheumatoid arthritis), spondyloarthropathy, and infection. Extraarticular causes include ligamentous injury, myofascial pain, enthesopathy, and pregnancy. Trauma and cystic disease may fall into either category. Patients with intraarticular causes of SIJ pain are more likely to be elderly with insidious onset of pain in bilateral SIJ and evidence of joint disease on imaging. Extraarticular pathology is more likely to be demonstrated in younger individuals who report a specific inciting event leading to unilateral pain.^4,5

4. The patient is asked to point to where it hurts. He points to a location just inferior to the left posterior superior iliac spine. After a series of provocative exam maneuvers you feel fairly confident that the pain is coming from the sacroiliac joint. What is the optimal number of provocative exam maneuvers that should be positive to suggest SIJ related pain?

A. 1
B. 2
C. 3
D. 4
E. 5
F. 6

C. The common sacroiliac pain provocation tests are Pelvic Distraction test, Thigh Thrust, Gaenslen’s, Pelvic Compression test, Sacroiliac Shear test, Yeoman’s (Extension) test, Gilet’s test and FABER-Patrick’s. A systematic review of 18 studies found a combination of three provocative tests has sufficient discriminative power in diagnosing SIJ pathology. These maneuvers should not be interpreted in isolation, as previous studies show they may be positive in 16%-33% of asymptomatic patients. SIJ pathology may confidently be ruled out when all six SIJ provocation tests are negative.^5-10

In addition, flexion, abduction, and external rotation (FABER or Patrick’s test) had the highest specificity and positive predictive value among special tests (FABER, Gaenslen’s, Thigh thrust, Distraction, Compression, Sacral Thrust). Fortin’s finger sign (as described in the vignette) is a reliable and easy test, completed by having the patient point with 1 finger to where the pain is. Pain located over the SIJ suggest SIJ-related pain, although it should be used in combination with other tests.^5-10

5. After performing provocative exam testing, you tell the patient there is one more test you would like to perform to diagnose his sacroiliac pain more accurately. Which test is considered the gold standard and most accurate diagnostic test for pain?

A. Fortin’s finger exam maneuver
B. Radiographs of the SIJ
C. Diagnostic block into the SIJ under fluoroscopic guidance
D. Magnetic resonance imaging of the pelvis and SIJ

C. Intraarticular injections with local anesthetics are considered the gold standard for diagnosing SIJ pain. Cutoff values are not clear for pain reductions after the injection; however, studies suggest either 70% or 75%. Level 2 evidence supports the use of dual diagnostic blocks with at least 70% pain relief and Level 3 evidence supports use of single diagnostic blocks with at least 75% pain relief. Studies suggest a positive predictive value of a single diagnostic block of 87.5% and a negative predictive value of 81.8%.^11,12

6. What initial treatment options would you recommend for this patient? 

Initial treatment focuses on symptom management with rest and activity modification. Alternating ice and heat and over-the-counter pain relievers such as nonsteroidal anti-inflammatory drugs may help relieve pain. If pain persists after a short trial of the above measures, referral to physical therapy should be considered. The rehabilitation focus should be on strengthening supporting musculature that includes the transversus abdominis, latissimus dorsi, gluteal muscles, hip external rotators, and pelvic floor muscles. Manual mobilization and manipulation could also be included in the treatment plan. The length of the therapy course is not well-defined, but common regimens are 4-10 weeks long.^1,13,14

7. If initial conservative treatments fail, what interventions would you offer this patient?

Initial interventions to consider include therapeutic intraarticular injections, with the most common injectate being steroid. A recent review of 15 total studies (12 injecting steroids and three using tumor necrosis factor inhibitors) suggested a good response in 80% of patients with a mean duration of improvement over eight months. The two controlled studies suggested significant results over placebo. These injections should be image-guided, as a study showed that only 22% of non-guided injections were intraarticular. If injections fail to provide sufficient pain relief, neuroablation of the posterior sensory innervation of the SIJ can be considered. A lateral branch nerve diagnostic block is typically performed prior to ablation. Although evidence is still limited, neuromodulation also may provide lasting pain relief. A small study of 16 patients with refractory SIJ pain showed that an implanted peripheral nerve stimulator with leads overlying the involved rami dorsales was successful with follow-up of up to four years. Surgical referral for SIJ stabilization or fusion is an option for persistent pain.^1,14-17

8. A medical student shadowing you on your procedure day asks which nerves are usually targeted in SIJ procedures. What is your response?

A. L4 medial branch nerve, L5 dorsal ramus, and lateral branch nerves of S1-S3
B. L5 medial branch and lateral branches of S1-S3
C. L4 and L5 medial branches and the dorsal rami of S1-S4
D. L4 and L5 dorsal rami
E. S1-S3 lateral branches

A. The exact innervation has become an important topic of investigation in research and is debated. Previous studies suggest there are separate anterior and posterior innervations. However, other authors support exclusive posterior innervation.

The posterior ligaments and aspect of the SIJ is innervated by the L5 dorsal ramus and the lateral branches of S1, S2, and S3. Some individuals have contributions from S4 as well. Infrequently, if there is sacralization of L5, then L4 may contribute to the posterior aspect of the joint as well.^1,5,18

References

1. Falowski S, Sayed D, Pope J, et al. A review and algorithm in the diagnosis and treatment of sacroiliac joint pain. J Pain Res 2020;13:3337-48. https://doi.org/10.2147/JPR.S279390

2. Buchanan P, Vodapally S, Lee DW, et al. Successful diagnosis of sacroiliac joint dysfunction. J Pain Res 2021;14:3135-43. https://doi.org/10.2147/JPR.S327351

3. Rashbaum RF, Ohnmeiss DD, Lindley EM, et al. Sacroiliac joint pain and its treatment. Clin Spine Surg 2016;29(2):42-8. https://doi.org/10.1097/BSD.0000000000000359

4. Cohen S. Sacroiliac joint pain. In: Benzon H, Raja SN, Fishman SM, et al. Essentials of Pain Medicine. 4^th ed. New York: Elsevier; 2018. 

5. Wagner G, Nelson A, Cohen S, et al. Buttock and sciatica pain. In: Benzon H, Rathmell J, Wu Christopher, et al. Practical Management of Pain. 6^th ed. New York: Elsevier; 2023.

6. Kokmeyer DJ, Van der Wurff P, Aufdemkampe G, et al. The reliability of multitest regimens with sacroiliac pain provocation tests. J Manipulative Physiol Ther 2002;25(1):42-8. https://doi.org/10.1067/mmt.2002

7. Fortin JD, Falco FJ. The Fortin finger test: an indicator of sacroiliac pain. Am J Orthop 1997;26(7):477-80.

8. Laslett M, Aprill CN, McDonald B, et al. Diagnosis of sacroiliac joint pain: validity of individual provocation tests and composites of tests. Man Ther 2005;10(3):207-18. https://doi.org/10.1016/j.math.2005.01.003

9. Nejati P, Sartaj E, Imani F, et al. Accuracy of the diagnostic tests of sacroiliac joint dysfunction. J Chiropr Med 2020;19(1):28-37. https://doi.org/10.1016/j.jcm.2019.12.002

10. Woznica D, Press J. Physical examination of the lumbar spine and sacroiliac joint. In: Malanga G, Mautner K. Musculoskeletal Physical Exam: An Evidenced Based Approach. New York: Elsevier; 2017. 

11. Simopoulos TT, Manchikanti L, Gupta S, et al. Systematic review of the diagnostic accuracy and therapeutic effectiveness of sacroiliac joint interventions. Pain Physician 2015;18(5):E713-56.

12. Buchanan P, Vodapally S, Lee DW, et al. Successful diagnosis of sacroiliac joint dysfunction. J Pain Res 2021;14:3135-43. https://doi.org/10.2147/JPR.S327351

13. Al-Subahi M, Alayat M, Alshehri MA, et al. The effectiveness of physiotherapy interventions for sacroiliac joint dysfunction: a systematic review. J Phys Ther Sci 2017;29(9):1689-94. https://doi.org/10.1589/jpts.29.1689

14. Mooney V, Pozos R, Vleeming A, et al. Exercise treatment for sacroiliac pain. Orthopedics 2001;24(1):11199347. https://doi.org/10.3928/0147-7447-20010101-14 

15. Wendling D. Local sacroiliac injections in the treatment of spondyloarthritis. What is the evidence? Joint Bone Spine 2020;87(3):209–13. https://doi.org/10.1016/j.jbspin.2019.06.003

16. Rosenberg JM, Quint DJ, de Rosayro AM. Computerized tomographic localization of clinically-guided sacroiliac joint injections. Clin J Pain 2000;16(1):18–212000. https://doi.org/10.1097/00002508-200003000-00004

17. Guentchev M, Preuss C, Rink R, et al. Long-term reduction of sacroiliac joint pain with peripheral nerve stimulation. Operative Neurosurgery 2017;13(5):634-9 https://doi.org/10.1093/ons/opx017

18. Falowski S, Sayed D, Pope J, et al. A review and algorithm in the diagnosis and treatment of sacroiliac joint pain. J Pain Res 2020;13:3337-48. https://doi.org/10.2147/JPR.S279390