Platelet-Rich Plasma Prolotherapy for Low Back Pain Caused by Sacroiliac Joint Laxity
The sacroiliac joints are subject to con-siderable stresses in weight-bearing and back-twisting movements. Trauma to the SI ligaments can occur with falls on the buttocks, car accidents, twisting and lifting injuries, and repetitive impact loading from excessive running (marathoners). Predisposing factors include hypermobile joint syndromes (such as Ehlers-Danlos syndrome; see Figure 1) and pregnancy resulting in hormonally induced laxity (relaxin). With an injury to the SI joint, pain tends to be unilateral and can refer to the posterior thigh, iliac fossa and buttocks. Sprains of the iliolumbar ligaments can also result in referred pain into the groin and genitalia. Non-traumatic causes of SI joint pain also include seronegative arthritides such as ankylosing spondylitis, reiter’s syndrome, and psoriatic arthritis.
SI joint ligament instability pain is aggravated with prolonged immobility—e.g., pain from the “cocktail party”-prolonged standing; “theatre”-prolonged sitting. Pain is often worse with turning in bed, getting out of bed, standing up from a seated position or stepping up with the affected leg. Clinical signs include contranutation (anterior torsion of the ilium relative to the sacrum) as reflected by the anterior superior iliac spine (ASIS) being lower and the posterior superior iliac spine (PSIS) being higher. Nutation is the opposite (as when doing the “pelvic tilt”). Provocative tests can be done supine (gapping test, femoral shear test, Laguere’s sign, Gaenslen’s test); prone (sacral apex pressure test, yeoman’s test, posterior iliac glide test); sitting (piedallu sign, supine-to-sit test); and standing (gillet’s knee-to-chest test). Clinical exam for diagnosis is, however, quite unreliable.1,2
A new scale to diagnose SI joint instability that responds to prolotherapy has been recently co-developed by the author and is undergoing validity/reliability testing (Whitmore-Gordons Sacroiliac Instability Tool; see Appendix A). SI joint dysfunction diagnosed by intra-articular blocks accounts for about 20% of chronic low back pain.3,4 Treatment options for SI joint pain include medication (anti-inflammatories, analgesics, cortisone injections), physiotherapy, psychological counseling, surgery (radiofrequency den-ervation, surgical fusion), cortisone and botulinum toxin-A injections,5 and prolotherapy.6 Prolotherapy injections with Platelet-rich Plasma (PRP) is a relatively new treatment. This paper documents its effective application in patients with SI joint ligament laxity and painful dysfunction.
It used to be thought (and sometimes is still taught) that there is no movement in the sacroiliac joints. Over 100 years ago, clinical observations documented SI joint movement in pregnant women with low back pain.8 Subsequent in-vivo studies using implanted metal markers and stereoradiography have shown small move-ments in normal individuals in prone hyperextension (2 degrees of backward rotation of the sacrum relative to the ileum; 0.2 degrees of inward rotation of the iliac crests; and translation gliding of 0.6mm between the sacrum and ilium).9 Movements were 30-40% smaller in men and tended to increase slightly with age. Larger angular rotations (6-8 degrees) and translations (2.5mm) were reported in one subject with recurrent SI problems.10 In-vitro cadaver studies using embedded lead spheres and CT scan analysis have also documented movement.11 Application of eccentric forces (up to 60% of body weight) to cadaver pelvises resulted in rotational and translation movement. Rotational movement was increased by 10% when the posterior or anterior ligaments were cut and by 30% when both were cut.12 Anteriorly, the symphysis pubis is a cartilaginous joint with an interpubic fibrocartilaginous disc between the two joint surfaces. The sacrococcygeal joint is another symphysis that is united by a fibrocartilaginous disc. Occasionally this joint is synovial and movable. With advanced age, this and the SI joint may fuse and become obliterated.
Prolotherapy is a medical procedure that involves the injection of proliferating agents such as 12.5% dextrose mixed with local anesthetic. The injections are di-rected into ligaments, particularly at their insertion into bone/joints. Stronger customized solutions to promote faster healing include P2G (phenol-glycerine-glucose), sodium morrhuate (cod liver oil extract) and a patient’s own blood (platelet enriched plasma). The goal of prolotherapy is to stimulate collagen formation and deposition. By doing so, ligaments are strengthened and joint stability is enhanced. Such strengthening has been supported by both animal and human studies.13-15
The first physician to report on prolotherapy was Earl Gedney, DO, in 1937, who reported on this type of joint-injection after using it successfully on his own thumb.16 At a later date, while performing a hernia operation, general surgeon George Hackett, MD, discovered by chance that injections given “(usually in error) at the junction of ligament and bone resulted in profuse proliferation of new tissue at this union.” He then spent the rest of his career developing and refining the injection techniques leading to the publication of his text Ligament and Tendon Relaxation Treated by Prolotherapy in 1956. He treated 543 chronic low back pain patients (ages 15 to 88 with pain duration of 4 to 56 years) and reported an 82% success rate with such patients considering themselves cured over periods ranging up to 12 years at follow-up. Subsequent supportive clinical studies include case series for chronic groin pain,17 whiplash,18 fibromyalgia19 and randomized controlled trials (RCTs) for knee osteoarthritis,20 finger-thumb osteoarthritis,21 and chronic low back pain.22,23 One two-year RCT for low back pain found improvement in both the active (dextrose) and placebo (saline) prolotherapy groups suggesting that even the needle itself has an effect.
Platelet-Rich Plasma Prolotherapy
Platelet-rich plasma prolotherapy (PRPP) involves the injections of autologous blood—in particular, the portion concentrated with platelets—back into the donor’s body at the site of concern.