Acute mechanical low back pain is one of the most common complaints for GP visits in the United States and across the Western World. The prevalence of mechanical low back pain is estimated to be up to 84% of the population, with a further 12% experiencing severe disability within their lifetime. In New Zealand, it is the leading contributor to disability, incurring significant medical costs, workers’ compensation and ACC claims. Most occurrences of low back pain are mechanical, meaning the pain intrinsically comes from the spine, surrounding soft tissues, spinal joints and/or intervertebral disks. For low back pain to be considered acute, it has to be present for less than four to six weeks. Acute mechanical low back pain is also commonly referred to as lumbar syndrome, lumbosacral sprain/strain, or idiopathic low back pain. 

What Causes Acute Mechanical Low Back Pain?

The causes of acute low back pain are usually mechanical, meaning the source of the pain is triggered by movement within the spinal column. This can lead to irritation or damage to the moving parts of the spine, impacting the ligaments, tendons, facet joints, vertebral bodies, intervertebral discs, or surrounding soft tissue that can lead to a reactive spasm. In the majority of instances of mechanical low back pain, the exact cause is identified in only 20% of cases, with the rest remaining unknown. Fortunately, most cases resolve quickly with time and low back pain treatment. While less common, other factors that can lead to acute low back pain include spinal stenosis, herniated discs, zygapophysial joint pain, discogenic pain, vertebral fractures, sacroiliac joint pain, and myofascial pain.