Below is an excerpt from "Spine Surgery: Products, Technologies, Markets & Opportunities, Worldwide, 2008-2017," report #M510 from MedMarket Diligence.
Degenerative Disc Diseases
The mechanics of bipedalism—walking on two legs—is often cited as a factor in the development of degenerative disease of the lumbar spine. Over a normal lifespan, humans endure microtraumas and undergo bodily changes that either alter or redistribute biomechanical forces unevenly on the lumbar region, resulting in lower back pain. The stresses and microtraumas associated with lumbar degenerative disk disease (LDDD) degrade the many structures that stabilize the spine, from the bony architecture to the intervertebral discs to the complex array of supporting muscles and ligaments. Changes to the structure of the intervertebral disc contribute to the condition. The collagen (protein) structure of the annulus fibrosis weakens over time, and the water and proteoglycan (PG) content of the disc decreases. These changes diminish the disc’s ability to handle mechanical stresses. In the end analysis, many factors, including genetic, inflammatory, traumatic, and infectious, likely work together to initiate LDDD.
The back pain associated with LDDD occurs with equal frequency among men and women. Peak incidence is around the age of 40. Estimates indicate that 175.8 million days of restricted activity each year are attributed to back pain. The condition accounts for more lost productivity than any other, with estimates running around 89 million lost work days per year. According to the National Center for Health Statistics, 14.3% of new patient visits to primary care physicians are for lower back pain, and about 13 million physician visits are made in connection with back pain complaints.
Spinal stenosis results from the progressive combined narrowing of the central spinal canal, the neurorecesses, and the neuroforaminal canals. The narrowing of the spinal canal may result from bulging or protrusion of the intervertebral disc annulus or from other factors. Spinal stenosis increases a patient’s risk for acute neurological injury. Symptoms of spinal stenosis include pain, motor weakness, or paresthesia.
Spinal stenosis involving the cervical and thoracic regions can contribute to neurological injury. When it involves the lumbar spine, spinal stenosis is most commonly linked with midline back pain and radiculopathy. In the United States, CT and MRI studies in patients who exhibit no symptoms and are younger than 40 years indicate a 4% to 28% occurrence of spinal stenosis. Most patients over the age of 60 exhibit spinal stenosis to some degree. Internationally, nations with large numbers of older citizens tend to have a higher occurrence of the disease.
Osteoporosis, a systemic skeletal disorder characterized by low bone mass and loss of bone tissue, leads to weak and fragile bones. People with osteoporosis are at increased risk of fractures, especially in the hip, spine, and wrist. Women make up 80% of all osteoporosis sufferers.
Because bone loss typically occurs without symptoms, osteoporosis is often called the “silent disease.” Many people are unaware that they have the disease until a bump or fall results in a fracture or a collapsed vertebra. These collapsed vertebrae might manifest themselves in severe back pain, loss of height, or in spinal deformities such as the stooped posture characteristic of kyphosis.
A combination of genetic and environmental factors leads to the development of the disease, which is typically classified into Types I, II, and III. Type I, or postmenopausal, osteoporosis is believed to result from deficiencies in estrogen or testosterone. These deficiencies accelerate bone loss; they can also cause bone to be more sensitive to the effects of parathyroid hormone, which speeds calcium release from bone. In the five to seven years following menopause, women can lose up to 20% of their bone mass, which makes them much more likely to develop the disease. Type II osteoporosis, also known as senile osteoporosis, occurs in people late in life due in part to decreased formation of bone. Type III osteoporosis occurs as an effect of certain medications like glucocorticoids or other conditions that cause bone loss. Worldwide, according to the International Osteoporosis Foundation, the disease affects about 1 in 3 women and about 1 in 8 men. In Type I and Type II osteoporosis, women are affected more often than men. Both sexes exhibit equal incidence for Type III.
Researchers have found that genetic factors play a key role in the pathogenesis of osteoporosis by regulating phenotypes that predispose to fracture. Most of the genes remain to be discovered. Important findings to emerge over recent years include the observation that different genes are responsible for the regulation of bone mineral density (BMD) in both genders and at different skeletal sites, and that many of the genes that are mutated in rare bone diseases such as osteopetrosis and sclerosing bone dysplasias also seem to contribute to the regulation of BMD in the normal population. Future research may look at better defining the functional mechanisms by which candidate gene polymorphisms affect bone cell function and bone mass.
In the United States, about 10 million people have osteoporosis. Of this total, eight million are women. According to estimates from the National Osteoporosis Foundation, 14 million Americans will be diagnosed with osteoporosis by 2020. If current trends continue, an additional 47 million will be at high risk of developing the disorder. The disease is cited as the primary cause in an estimated 1.5 million or more bone fractures annually. This total includes about 700,000 vertebral fractures, 250,000 wrist fractures, 300,000 hip fractures, and 300,000 fractures at other sites. For people over the age of 50, one in two women and one in four men will have an osteoporosis-related fracture in their lifetime.
Recent studies indicate that about 1 of 13 postmenopausal women with osteoporosis who exhibit no fractures initially are likely to suffer a spinal fracture within one year. Related statistical models indicate that spinal fracture prevalence among these women increases rapidly over time if the condition is left untreated. Results of other studies indicate that 1 out of 5 postmenopausal, osteoporotic women who suffer an initial spinal fracture will experience another spinal fracture within a single year.
According to figures supplied by the National Osteoporosis Foundation, the estimated national direct expenditures for osteoporosis totaled $17 billion in 2001. By 2020, the cost of fall injuries is projected to reach $32.4 billion. The incidence of osteoporotic fractures—and the costs associated with them—increases with age. As life expectancy increases for much of the world’s population, these costs will multiply exponentially.
Rheumatoid arthritis (RA) is an inflammatory disease of unknown cause. Common symptoms include fatigue, malaise, and morning stiffness. The disease primarily affects the peripheral joints; because it causes joint destruction, it often leads to significant morbidity.
Although an infectious cause has been speculated, to date no organism has been proven responsible for initiating the disease.
Rheumatoid arthritis is linked to various autoimmune responses, but it remains unclear if autoimmunity is a primary or secondary event. The disease has a significant genetic component, with up to 90% of RA patients exhibiting a shared epitope of the LLA-DR4/DR1 cluster. Although the disease is observed in children and the elderly, it typically peaks in persons between the ages of 35 and 50. Females are two to three times more likely to develop rheumatoid arthritis than are males. Smoking cigarettes or cigars increases the risk for developing rheumatoid arthritis by up to 50 percent. The prevalence rate for the disease worldwide is about 1%, and the incidence is about 3 cases per 10,000 population. Because worldwide frequency of the disease is relatively constant, it is thought that a ubiquitous infectious agent may play a causative role.