Medical Library

It is estimated that approximately 80% of people worldwide will experience low back pain at some point in their lives. Among the working population, about 50% acknowledge having low back pain each year. In the United States alone, complaints of low back pain are reported by 15-20% of individuals annually. Moreover, around 2% of the U.S. population faces temporary or chronic disability due to low back pain, resulting in significant economic costs of approximately 100 billion dollars in lost wages, productivity, medical expenses, and time.

It is crucial to recognize that there is a high likelihood of recovering from low back pain in the near future. Research studies have demonstrated that 74% of individuals who experience back pain return to work within 4 weeks, and over 90% within 3 months or less. Some healthcare professionals compare low back pain to catching a cold – you experience it, and over time, it tends to resolve on its own.

To summarize, the chances of experiencing low back pain are quite high, but there is also a good probability of recovering from it. However, there is also a possibility of experiencing pain again in the future. Medical research suggests that an active exercise program can reduce disability and potentially prevent future episodes of pain.

The low back, also known as the lumbar spine, is an incredibly intricate and remarkable structure comprising various components such as bones, discs, joints, tendons, muscles, ligaments, and nerves. Functionally, the spine serves three primary purposes. Firstly, it acts as a connecting link between the pelvis, trunk, and head. Secondly, it safeguards and encloses the spinal cord, which consists of countless nerves that establish connections between the brain and the body's major organs. Lastly, the spine provides stability, balance, flexibility, and mobility necessary for carrying out our daily activities. It enables activities like swinging a golf club while withstanding and transferring substantial forces. For instance, if you weigh 150 pounds and bend over at approximately 65 degrees, your back muscles generate around 375 pounds of force to maintain balance. Furthermore, if you simultaneously carry a 50-pound object, your muscles generate approximately 700 pounds of force.

A closer examination reveals a stack of five vertebrae (bones) with fluid-filled discs positioned between them. The lumbar spine takes the shape of a hollow, C-shaped curve known as the lumbar lordosis, which is specifically designed to withstand significant forces. This curvature enhances the spine's strength, making it about 15 times stronger compared to a straight spine. Within the "hollow" of the spine resides the spinal cord, composed of nerves responsible for transmitting signals from the brain to the muscles, coordinating their contractions. These nerves also facilitate sensations such as touch and pain. They exit the spinal cord through small openings called intervertebral foramen, known as nerve roots.

The vertebral bodies bear the majority of the weight and feature cartilage end plates that attach to the discs. Each vertebra has spinous processes protruding from the back and two additional bones called transverse processes pointing sideways, serving as attachment sites for muscles and ligaments.

Between each vertebral body lies a fluid-filled disc, akin to a jelly donut. The outer fibrous portion is called the annulus fibrosus, while the inner jelly-like substance is known as the nucleus pulposus. Healthy discs play a crucial role in maintaining spinal height, absorbing shocks, and evenly distributing forces in all directions.

Ligaments, which are sturdy but minimally stretchable structures, play a vital role in the low back. Numerous ligaments are associated with the lumbar spine. The anterior longitudinal ligament holds the front part of the vertebral bodies together, while the posterior longitudinal ligament holds the back part. The interspinous and intertransverse ligaments pass between the spinous processes and transverse processes, respectively. The ligamentum flavum holds the rear section of the vertebrae together and aids in protecting the spinal cord. The thoracolumbar fascia, a large ligamentous tissue, contributes to the stability of the lumbar vertebrae, working in conjunction with muscles.

Over 140 muscles collaborate to facilitate movement and stability of the spine, many of which are located in the lumbar region. These include the abdominal muscles, erector muscles, hip muscles, and lateral stabilizing muscles. The abdominal muscles encompass the rectus abdominis, internal and external obliques, and transverse abdominis. They provide frontal support, maintain proper posture, hold the abdominal organs in place, and act as a natural "back belt" for the body. The erector spinae muscles run along the back, assisting in maintaining an upright posture and aiding in the recovery from forward bending positions. Deeper muscles are involved in rotational movements and side bending. The hip muscles, particularly the gluteus maximus, hamstrings, and psoas, play a role in pelvis and thigh movements. The gluteus maximus and hamstrings are significant muscles for lifting activities, with around 67% of bending during activities like touching your toes originating from the hips, controlled by these muscles. The psoas muscles help lift the thighs and stabilize the spine. The lateral stabilizers, such as the quadratus lumborum and latissimus dorsi, attach to the spinous and transverse processes through the thoracolumbar fascia. They contribute to the stability and movement of the spine. Any individual structure or combination thereof can influence the lumbar lordosis or curve of the low back.

Mechanical Low Back Pain

Mechanical low back pain can stem from various factors, including traumatic incidents such as falls, motor vehicle accidents, twisting motions, prolonged poor postures, mental stress, fatigue, disc extrusion (commonly known as a slipped disc, rupture, or herniation), degenerative disc disease (also referred to as arthritis), aging, congenital defects, and poor flexibility. However, it is important to note that causes like infections, hormonal issues, fractures, systemic diseases, and tumors require serious medical attention but are rare occurrences and beyond the scope of this discussion.

Acute low back pain is characterized by a limited ability to engage in activities due to symptoms in the lower back or back-related leg pain lasting less than three months. Chronic low back pain, on the other hand, refers to pain or problems that persist for more than three months. Regardless of the cause or duration of mechanical low back pain, it is likely that soft tissues have sustained damage, which can stimulate nerves and result in pain.

It is crucial to understand that identifying the exact tissue(s) responsible for low back pain is extremely challenging, if not impossible. Individuals, like yourself, may experience pain without a clear cause. The pain could be originating from muscles, ligaments, discs, tendons, joints, or other connective tissues. These structures can produce similar symptoms, typically manifesting as pain on one side or across the back. The pain may radiate into the buttock or thigh and is often accompanied by muscle spasms and cramping. Moreover, medical research has demonstrated that X-rays are generally unhelpful in pinpointing the cause of low back pain, except in severe trauma cases. Magnetic resonance imaging (MRI) is also not very effective in determining the cause. For example, two out of three individuals may exhibit disc abnormalities on an MRI but experience no pain. Similarly, one in three people may have disc bulges without any pain. Healthcare professionals often refer to low back pain as a "pain in search of a pathology," indicating that medical tests may yield negative results or false positives. The cause of the pain could involve any number of structures.

When it comes to treating low back pain without a precise diagnosis, the focus lies on addressing the damaged soft tissue that is causing the pain. The objective is to facilitate the healing process of the affected tissues, leading to the elimination of pain rather than merely treating the symptoms. This involves implementing a customized program tailored to your specific needs.

Here are the steps involved in the treatment process:

1. Protecting the damaged soft tissue: The first step is to safeguard the area of damaged tissue from further breakdown. This is achieved through rest and appropriate positioning. Activities that trigger pain should be avoided to allow the low back to heal. Your physical therapist will discuss pain management techniques that can be utilized during this phase. Bed rest is typically recommended for only 1-3 days, as prolonged periods have not proven to be beneficial.
2. Enhancing circulation and mobility: Increasing circulation is crucial to deliver essential building blocks like proteins, repair cells (fibroblasts), oxygen, and nutrients to the damaged tissues. It also aids in the removal of inflammatory and waste products that accumulate in painful areas. Walking and engaging in a painless range of motion, stretching, and strengthening exercises are effective ways to boost circulation and mobility.
3. Correcting dysfunctions: Identifying and addressing the underlying dysfunctions that initially caused the problem is essential for long-term recovery. Weakness, poor posture, and limited flexibility are common factors contributing to low back pain. Progressive strengthening exercises, flexibility exercises, and education on postural alignment and proper body mechanics help alleviate stress on the low back and promote optimal repair.

The Key: Your physical therapist will equip you with the necessary tools to address your specific dysfunctions and create a customized treatment program. However, it's important to note that resolving low back pain extends beyond the cessation of pain itself. Muscles need to be stronger than they were prior to the onset of pain (which typically takes 12 or more weeks), several weeks are required to improve flexibility, and consistent practice is necessary to incorporate proper posture and body mechanics into your daily activities.