Lower back pain after pregnancy: what might be causing it and how can you make the pain go away? The SI joint may be to blame.
The SI Joint May Be to Blame for Post-Partum Pelvic Girdle Pain
The sacroiliac (SI) joints are located between the spine and the hip joints. The SI joints are responsible for absorbing and transferring the large amounts of force that are generated in the spine and lower extremities during physical activities. The SI joints are particularly vulnerable to injury because of their location and their orientation. The SI joints provide the crucial balance between pelvis stability and pelvis mobility.
Post-partum pelvic girdle pain (PPGP) (which may include the SI joint(s)) will resolve in most women within 4 months after giving birth,45 but 20% of women who experience this pain during and immediately after pregnancy report continuing pain two and three years postpartum.46 The underlying causes of PPGP are not well defined, with the explanation most likely being a combination of hormonal, biomechanical, and traumatic factors.47
Potential Causes of PPGP
Hormonal: Relaxin is a hormone that the body produces in increased amounts during pregnancy. This hormone helps increase the flexibility of the ligaments that support the SI joints. This facilitates the widening of the birth canal that occurs during delivery.
Biomechanical: As pregnancy progresses, some of the core muscles (transverse abdominals and pelvic floor) are stretched due to the increasing size and weight of the fetus. Stretching of these muscles may lead to a decrease in the ability of these muscles to stabilize the pelvic joints
As the fetus grows during pregnancy, the center of gravity shifts forward and remains forward in the post-partum period. This typically results in a forward rotation of the pelvic bones, leading to increased load, decreased functional stability and increased wear and tear of the SI joints.48
Traumatic: 52% of women with pregnancy related low back and pelvic pain have pelvic floor dysfunction including a change in the firing of the muscles (change of motor control).49 This may be due to direct injury of the pelvic floor muscles or injury to the nerves that innervate the pelvic floor muscles during pregnancy and/or delivery. A biomechanical study by Pel showed increased stability of the SI joints with contraction of the pelvic floor and the transverse abdominal muscles together.50
Diagnosis of PPGP/SI joint pain is usually made with history and physical examination. Physical examination typically includes a series of provocative tests (physical maneuvers performed by the examiner that stress the SI joints in different directions). Diagnosis is confirmed with a diagnostic SI joint injection. During the injection procedure, a small amount of numbing medicine (a local anesthetic such as lidocaine) is injected into the SI joint under fluoroscopic guidance. If the injection results in a significant decrease in SI joint pain (more than 75% pain relief) for an hour or two after the injection, then this is considered a positive or confirmatory diagnostic injection.
There has been some research on the non-surgical treatment of PPGP including physical therapy and other conservative measures such as injections and RFA. Physical therapy is performed to increase the functional stability of the pelvic (SI) joints. Physical therapy treatment of sacroiliac joint pain should ideally address the underlying muscle and ligament problems. Treatments with a physical therapist will typically focus on restoring normal pelvis and core muscle stability (Transversus Abdominis, Multifidus and Pelvic Floor muscles) as these muscles are responsible for what is known as Force Closure of the pelvis,47 which creates a dynamic active compressive force and stabilization of the SI joints. Physical therapy is a therapeutic option that may provide relief for some women, but has also been shown to exacerbate symptoms in others.
This treatment along with exercises to improve general spinal stability, improve body mechanics, correct postural problems, strengthen and/or stretch specific muscles to balance the muscle groups that surround, attach to, and support the SI joints, combined with general physical conditioning are considered “best practice.” There is little formal research to support these recommendations as the treatments are highly individualized to the specific patient making it difficult to draw conclusions across a broad range of patients.
An SI belt, a non-elastic strap placed temporarily around the pelvic joints, has also been found to reduce the sensation of abnormal movement and may aid with symptom reduction.51,52 Other non-surgical treatment options include injection of medications (steroids) into the joint to decrease inflammation and pain, and radiofrequency ablation (RFA). RFA is a procedure where heat or cold is used to temporarily deaden the sensory nerves over the SI joints in order to decrease their ability to transmit pain signals coming from the SI joint.
If a patient continues to have disabling SI joint pain after 6 months or more of appropriate non-surgical treatment, then the patient may benefit from an iFuse minimally invasive surgical (MIS) procedure to fuse the SI joint. The iFuse procedure, available since 2009, has been shown to provide improvement in pain, disability and quality of life in many high-quality studies including two randomized controlled trials (RCTs).18,19 Patients with SI joint pain that began in the peri-partum period that received the iFuse procedure showed significant long-term reduction in pain and marked improvement in physical function and in quality of life.53
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More Related Resources
Here's a quiz to determine whether your SI joint is a contributor to pain in your lower back, pelvic region, buttocks, or legs.
More links and information regarding the diagnosis and treatment of SI Joint Pain:
How do I Know that my SI Joint is not Functioning Properly?
If you have trouble sleeping comfortably, or frequently experience your leg giving way, pain in certain lying or bending positions, or tenderness in your buttocks, you may have an SI joint disorder. Visit your doctor to determine the cause of your low back pain.