Low back pain (LBP) is a significant source of morbidity that affects a significant portion of the population. While initially a mainstay in therapy, surgical interventions have come under intense scrutiny as research has questioned their efficacy in addressing LBP. Nonspecific LBP (NSLBP) is particularly difficult to treat because multiple etiologies can contribute to ongoing pain. Mechanical dysfunction of the sacroiliac joint (SIJ) has been targeted as a common source of low back pain amenable to treatment. Several authors, including TOBI faculty Dr. Jennifer Saunders, undertook to compare the efficacy of PRP and prolotherapy injections in addressing SIJ-related pain.
Treatment of the SIJ-related pain is modeled in the mechanics of the joint, including form and force closure of the joint. Form closure results from interlocking of the surfaces between the sacrum and the iliac bones with some contribution from the dorsal interosseous sacroiliac ligaments (DIOL). Force closure results from sequential contraction of the abdominal core muscles that lock the sacrum into the pelvic ring. This sequential contractility may be impaired if typical mechanics are disrupted. This can occur if the DIOL is damaged and leads to loss of force closure.
Physical therapy can address SIJ dysfunction by reestablishing sequential contractility, but presumes integrity of the DIOL. Significant DIOL damage can lead to therapy failure because of ongoing mechanical disruption that destabilizes the SIJ. Prolotherapy and PRP have both been used in cases where therapy has failed to address ongoing DIOL dysfunction and instability. The relative effectiveness of each treatment has not been well-established and the authors set out to compare these two methods of treatment directly.
To do so, they recruited 48 patients with lumbosacral pain with at least three clinical signs of SIJ dysfunction who had failed at least three months of physical therapy. All patients were treated with PRP injected under ultrasound guidance into the DIOL rather than into the synovial portion of the SIJ. Pain was typically reproduced during the injection, confirming the source of the patient’s pain. This was also confirmed using a SPECT/CT scan to localize injury to the DIOL. Two injections were performed with the second done six weeks to three months after the first procedure. The patients were reevaluated at three and 12 months. Their results were then compared to a prior data set of those treated with several prolotherapy injections performed under CT guidance.
Interestingly, the authors also collected information on location of pain complaints and noted that SIJ pain can follow a distribution similar to sciatica. This likely occurs because the periarticular tissues have the same nerve supply as the intervertebral discs.
The authors found no significant difference between the PRP and prolotherapy groups on any of the measures used including the visual analogue scale (VAS), the Roland-Morris questionnaire (RM), and the Quebec back pain inventory at three months. However, scores continued to improve in the PRP group at 12 months leading to superior long-term results in the PRP group over the prolotherapy group.
The authors hope that their study adds data behind alternative options for treatment of SIJ mechanical dysfunction, specifically when DIOL injury is present. They note that their study also demonstrates the importance of precision in treatment, both in choice and in placement of the therapeutic agent.
We congratulate the authors on their publication and thank them for their work!