Low back pain

Low back pain (or lumbago, English pronunciation: /lʌmˈbeɪgoʊ/) is a common musculoskeletal disorder affecting 80% of people at some point in their lives. In the United States it is the most common cause of job-related disability, a leading contributor to missed work, and the second most common neurological ailment — only headache is more common.^[1] It can be either acute, subacute or chronic in duration. With conservative measures, the symptoms of low back pain typically show significant improvement within a few weeks from onset.

What is the anatomy of the low back?

The first step to understanding the various causes of low back pain is learning about the normal design (anatomy) of the tissues of this area. Important structures of the low back that can be related to symptoms there include the bony lumbar spine (vertebrae, singular = vertebra), discs between the vertebrae, ligaments around the spine and discs, spinal cord and nerves, muscles of the low back, internal organs of the pelvis and abdomen, and the skin covering the lumbar area.
The bony lumbar spine is designed so that vertebrae "stacked" together can provide a movable support structure while also protecting the spinal cord from injury. The spinal cord is composed of nervous tissue that extends down the spinal column from the brain. Each vertebra has a spinous process, a bony prominence behind the spinal cord, which shields the cord's nervous tissue from impact trauma. Vertebrae also have a strong bony "body" (vertebral body) in front of the spinal cord to provide a platform suitable for weight bearing of all tissues above the buttocks. The lumbar vertebrae stack immediately atop the sacrum bone that is situated in between the buttocks. On each side, the sacrum meets the iliac bone of the pelvis to form the sacroiliac joint of the buttocks.
The discs are pads that serve as "cushions" between the individual vertebral bodies. They help to minimize the impact of stress forces on the spinal column. Each disc is designed like a jelly donut with a central softer component (nucleus pulposus) and a surrounding outer ring (annulus fibrosus). The central portion of the disc is capable of rupturing (herniating) through the outer ring, causing irritation of adjacent nervous tissue and sciatica as described below.
Ligaments are strong fibrous soft tissues that firmly attach bones to bones. Ligaments attach each of the vertebrae to each other and surround each of the discs.
The nerves that provide sensation and stimulate the muscles of the low back as well as the lower extremities (the thighs, legs, feet, and toes) exit the lumbar spinal column through bony portals, each of which is called a "foramen."
Many muscle groups that are responsible for flexing, extending, and rotating the waist, as well as moving the lower extremities, attach to the lumbar spine through tendon insertions.
The aorta and blood vessels that transport blood to and from the lower extremities pass in front of the lumbar spine in the abdomen and pelvis. Surrounding these blood vessels are lymph nodes (lymph glands) and tissues of the involuntary nervous system that are important in maintaining bladder and bowel control.
The uterus and ovaries are important pelvic structures in front of the pelvic area of women. The prostate gland is a significant pelvic structure in men. The kidneys are on either side of the back of the lower abdomen, in front of the lumbar spine.
The skin over the lumbar area is supplied by nerves that come from nerve roots that exit from the lumbar spine.

The majority of lower back pain stems from benign musculoskeletal problems, and are referred to as non specific low back pain; this type may be due to muscle or soft tissues sprain or strain,^[3] particularly in instances where pain arose suddenly during physical loading of the back, with the pain lateral to the spine. Over 99% of back pain instances fall within this category.^[4] The full differential diagnosis includes many other less common conditions.

• Mechanical:
  • Apophyseal osteoarthritis
  • Diffuse idiopathic skeletal hyperostosis
  • Degenerative discs
  • Scheuermann's kyphosis
  • Spinal disc herniation ("slipped disc")
  • Thoracic or lumbar spinal stenosis
  • Spondylolisthesis and other congenital abnormalities
  • Fractures
  • Leg length difference
  • Restricted hip motion
  • Misaligned pelvis - pelvic obliquity, anteversion or retroversion
  • Abnormal Foot Pronation

• Inflammatory:
  • Seronegative spondylarthritides (e.g. ankylosing spondylitis)
  • Rheumatoid arthritis
  • Infection - epidural abscess or osteomyelitis

• Neoplastic:
  • Bone tumors (primary or metastatic)
  • Intradural spinal tumors

• Metabolic:
  • Osteoporotic fractures
  • Osteomalacia
  • Ochronosis
  • Chondrocalcinosis

• Psychosomatic
  • Tension myositis syndrome

• Paget's disease

• Referred pain:
  • Pelvic/abdominal disease
  • Prostate Cancer
  • Posture

• Depression^[5]
• Oxygen deprivation

What is the treatment for low back pain?

So, how is low back pain treated? Well, as described above, the treatment very much depends on the precise cause of the low back pain. Moreover, each patient must be individually evaluated and managed in the context of the underlying background health status and activity level.
As has been highlighted by research presented at the national meeting of the American College of Rheumatology, a very important aspect of the individual evaluation is the patient's own perception of their particular situation. British researchers found that those who believed that their symptoms had serious consequences on their lives and that they had, or treatments had, little control over their symptoms were more likely to have a poor outcome. This research points out to physicians the importance of addressing the concerns and perceptions that patients have about their condition during the initial evaluations.
Finally, it should be noted that the conditions listed above are intended for general review. There are many other causes of back pain, including upper back pain, that have not been discussed.

 

 

Posted in: