By Daryll C. Dykes, MD
Low back pain (LBP) is a nearly universal condition, affecting most adults at some point during their lifetime. Men and women are equally affected with a peak occurrence between the ages of 30 and 50. While LBP remains a considerable source of disability and health care expenditure (Americans spend approximately $50 billion per year on LPB-related conditions), typical episodes are short-lived and respond well to simple treatments. Fortunately, only rarely are occurrences of LBP related to any serious or dangerous condition.
The human spine is a unique structure that is elegantly designed to carry out several important functions. On one hand, it must be strong and stable enough to support the body’s weight and to protect the delicate spinal cord and nerves; while on the other hand, it must be flexible enough to allow the intricate and coordinated motions of the body. This is achieved through a series of specialized bones – the vertebrae – stacked on top of one another. The vertebrae are joined by cartilage-lined joints in the back of the spine (called facet joints) and separated by intervertebral discs in the front of the spine. The discs act as “shock absorbers” between the vertebrae and provide the flexibility to the spine. Strong connective tissues, such as tendons, ligaments and muscles connect the discs to the vertebral endplates (the upper and lower surfaces of the vertebrae) and to the remainder of the body. The back half of each vertebra has an oval-shaped hole from top to bottom, which, when aligned with the vertebra above and below, produces a channel called the spinal canal that houses the spinal cord. Gaps between the stacked vertebrae – called foramen – provide portals for the smaller nerve roots traveling to and from the spinal cord. LBP originates in the lumbar segment of the spine representing the five lowest vertebrae and discs.
LBP may originate in any of the structures in the lumbar region such as fractures of the vertebrae, tearing or rupture of the intervertebral discs, pinching or irritation of the nerve roots, or straining of the muscles, tendons or ligaments. Most commonly, degeneration of the intervertebral discs is the underlying culprit. Degenerative Disc Disease (DDD) represents of spectrum of conditions initiated by drying out of the discs and resulting in disc collapse, tearing, and bulging. Changes in the protective functions of the disc ultimately lead to degenerative changes of the vertebral endplates and facet joints. While the causes of DDD are not completely understood, genetic factor seem to be significant contributors. Specific trauma, such as a lifting injury, sports injury, a sudden jolt or repetitive physical strain may precipitate LBP in individuals with otherwise pain-free disc degeneration. Obesity, smoking, poor aerobic conditioning significantly contribute to both DDD and DDD-related LBP.
In general, LBP can be divided into “acute” and “chronic” categories, depending on the duration of symptoms. Acute LBP is most common, lasting from a few hours to several weeks. Chronic LBP describes symptoms that persist for more than three months or reoccurring episodes of acute LBP over a longer period of time. Rarely, acute or chronic LBP may be accompanied by constant severe pain, fever, alteration in bowel or bladder control or progressive weakness of the legs that may signify fracture, infection, tumor or other potentially serious condition. In the case of such “red flags”, patients should seek immediate medical evaluation and treatment.
Non-operative management is the mainstay of treatment for acute LBP. Short-term activity modifications, over-the-counter nonsteroidal anti-inflammatory medications (such as aspirin, ibuprofen and naproxen), and application of ice (usually more effective in the early phases) or heat (usually more effective in the later phases) are effective management for most episodes of acute LBP. Long-term bed rest has been shown to be ineffective and may actually worsen symptoms. Individuals with acute LBP symptoms not showing signs of improvement within 72 hours should seek advice from a qualified health care provider.
Medical evaluation of LBP begins with the taking of a thorough medical history and physical exam. This is usually sufficient to make a diagnosis and initiate treatment. In cases of atypical findings on the initial screening, or in the case of prolonged symptoms, the health care provider may initiate routine diagnostic tests including laboratory blood tests, x-rays, MRI scans or CT scans. Specialized diagnostic procedures such as electromyography, bone scans, discograms or other x-ray-guided spinal injections may be necessary if routine tests do not provide definitive diagnoses.
Prescription medications, physical therapy modalities and spinal manipulation are usually effective in cases failing to respond to self-care. X-ray-guided injections of anesthetics and/or steroid medications can be highly-effective treatments for acute back pain or leg pain associated with DDD. Yoga, biofeedback, acupuncture are low-risk interventions that may be useful in pain relief.
Surgery is rarely necessary for management of LBP. When patients fail to improve with time and appropriate non-surgical measures, surgical procedures may be considered for the management of chronic LBP. The most common surgical procedures include laminectomy or discectomy to decompress pinched nerve roots and fusion surgery to remove painful degenerative discs and stabilize unstable spinal segments. Decompression surgery is associated with high levels of success, and is usually completed through small surgical incisions with minimal risk and relatively quick recovery. Fusion surgery usually involves the insertion of bone grafts with screws, rods, cages or other biomechanical implants. This has been associated with more variable outcomes and typically involves greater surgical risks, longer recovery times and some degree of lost flexibility of the spine. Recently, both types of procedures have benefited from advancements in “less invasive” surgical techniques that allow completion of the surgical procedure with less disruption to normal surrounding tissues. Technological advances in implant design and the availability of laboratory-produced fusion enhancing substances (bone morphogenetic proteins, or BMP) have also led to improved outcomes of surgical procedures. While long-term outcome information is not yet available, significant interest has emerged in disc arthroplasty (artificial disc replacement) as an alternative to fusion surgery, with several disc replacement devices being recently approved by the US Food and Drug Administration. Ongoing research is providing promise for even more effective and less invasive treatments in the future. Because there are many different factors to consider and no two cases of DDD are identical, only a qualified spinal surgeon can determine the appropriate treatment options for any given situation.
As with all musculoskeletal prevention of repetitive injury is an important consideration for LBP. Generalized fitness, proper body mechanics and a balanced diet (with sufficient daily intake of calcium, vitamin D and phosphorous) are important to spinal health.
Daryll C. Dykes, M.D., PhD is a renowned expert on spinal care and disorders, including arthritis, fractures, deformities and tumors. He is engaged in ongoing clinical research to study advances in both operative and non-operative treatments.
Dr. Dykes graduated from Syracuse University in 1986 with a Bachelor’s of Science in Biology, concentrating in Microbiology and Immunobiology. He received his PhD in 1992 and his MD in 1995 from State University of New York – Syracuse. He has a State of Minnesota Medicine and Surgery license and is certified by the American Board of Orthopaedic Surgery.
His career recognition includes: the President’s Award For Excellence in Research, SUNY Health Science Center at Syracuse; 1st Place Award – Student National Medical Association National Research Forum and Competition, New Orleans; the Dr. Henry A. Washington Brother of the Year Award, 1991-1992 (for Community Service, Academic, and Professional Achievement); American Society of Clinical Pathologists, Award for Academic Excellence; the Premedical Society of Syracuse University, Outstanding Alumnus Award; SUNY-HSC Department of Pathology Award for Excellence in Pathology; American Heart Association Award for Excellence in Medical Research; the James L. Potts, M.D. Public Service Award; the David G. Murray, M.D. Award for Excellence in Orthopedic Surgery.
Dr. Dykes is a veteran of the United States Marine Corps and currently practices at the Twin Cities Spine Center in Minneapolis, MN. Dr. Dykes is a spokesperson for the American Academy of Orthopaedic Surgeons.