1、Low back pain (LBP) Cause A herniated disc as seen on MRI, one possible cause of low back pain The majority of LBP is believed to be the result of non-serious muscle or skeletal issues such as sprains or strains. Obesity, smoking, weight gain during pregnancy, stress, poor physical condition, poor p
2、osture and poor sleeping position may also contribute to low back pain. A full list of possible causes includes many less common conditions. Physical causes may include osteoarthritis, degeneration of the discs between the vertebrae or a spinal disc herniation, a broken vertebrae (such as from osteo
3、porosis) or, rarely, an infection or tumor of the spine. Women may have acute low back pain from medical conditions affecting the female reproductive system, including endometriosis, ovarian cysts, ovarian cancer, or uterine fibroids. Nearly half of all pregnant women report pain in the lower back o
4、r sacral area during pregnancy, due to changes in their posture and center of gravity causing muscle and ligament strain. Low back pain can be broadly classified into four main categories: Musculoskeletal - mechanical (including muscle strain, muscle spasm, or osteoarthritis); herniated nucleus pulp
5、osus, herniated disk; spinal stenosis; or compression fracture Inflammatory - HLA-B27 associated arthritis including ankylosing spondylitis, reactive arthritis, psoriatic arthritis, and inflammatory bowel disease Malignancy - bone metastasis from lung, breast, prostate, thyroid, among others Infecti
6、ous - osteomyelitis; abscess Pathophysiology Back structures The five lumbar vertebrae define the lower back region The structures surrounding and supporting the vertebrae can be sources of low back pain The lumbar (or lower back) region is made up of five vertebrae (L1-L5), sometimes including the
7、sacrum. In between these vertebrae are fibrocartilaginous discs, which act as cushions, preventing the vertebrae from rubbing together while at the same time protecting the spinal cord. Nerves come from and go to the spinal cord through specific openings between the vertebrae, providing the skin wit
8、h sensations and messages to muscles. Stability of the spine is provided by the ligaments and muscles of the back and abdomen. Small joints called facet joints limit and direct the motion of the spine. The multifidus muscles run up and down along the back of the spine, and are important for keeping
9、the spine straight and stable during many common movements such as sitting, walking and lifting. A problem with these muscles is often found in someone with chronic low back pain, because the back pain causes the person to use the back muscles improperly in trying to avoid the pain. The problem with
10、 the multifidus muscles continues even after the pain goes away, and is probably an important reason why the pain comes back. Teaching people with chronic low back pain how to use these muscles is recommended as part of a recovery program. An intervertebral disc has a gelatinous core surrounded by a
11、 fibrous ring. When in its normal, uninjured state, most of the disc is not served by either the circulatory or nervous systems blood and nerves only run to the outside of the disc. Specialized cells that can survive without direct blood supply are in the inside of the disc. Over time, the discs los
12、e flexibility and the ability to absorb physical forces. This decreased ability to handle physical forces increases stresses on other parts of the spine, causing the ligaments of the spine to thicken and bony growths to develop on the vertebrae. As a result, there is less space through which the spi
13、nal cord and nerve roots may pass. When a disc degenerates as a result of injury or disease, the makeup of a disc changes: blood vessels and nerves may grow into its interior and/or herniated disc material can push directly on a nerve root. Any of these changes may result in back pain. Diagnosis As
14、the structure of the back is complex and the reporting of pain is subjective and affected by social factors, the diagnosis of low back pain is not straightforward. While most low back pain is caused by muscle and joint problems, this cause must be separated from neurological problems, spinal tumors,
15、 fracture of the spine, and infections, among others. Classification There are three general types of low back pain by cause: mechanical back pain (including nonspecific musculoskeletal strains, herniated discs, compressed nerve roots, degenerative discs or joint disease, and broken vertebra), non-m
16、echanical back pain (tumors, inflammatory conditions such as spondyloarthritis, and infections), and referred pain from internal organs (gallbladder disease, kidney stones, kidney infections, and aortic aneurysm, among others). Mechanical or musculoskeletal problems underlie most cases (around 90% o
17、r more), and of those, most (around 75%) do not have a specific cause identified, but are thought to be due to muscle strain or injury to ligaments. Rarely, complaints of low back pain result from systemic or psychological problems, such as fibromyalgia and somatoform disorders. Low back pain may be
18、 classified based on the signs and symptoms. Diffuse pain that does not change in response to particular movements, and is localized to the lower back without radiating beyond the buttocks, is classified as nonspecific, the most common classification. Pain that radiates down the leg below the knee,
19、is located on one side (in the case of disc herniation), or is on both sides (in spinal stenosis), and changes in severity in response to certain positions or maneuvers is radicular, making up 7% of cases. Pain that is accompanied by red flags such as trauma, fever, a history of cancer or significan
20、t muscle weakness may indicate a more serious underlying problem and is classified as needing urgent or specialized attention. Red flags(warning signs that may indicate a more serious problem) Red flag Possible cause Previous history of cancer Cancer Unintentional weight loss Loss of bladder or bowe
21、l control Cauda equina syndrome Significant motor weakness or sensory problems Loss of sensation in the buttocks (saddle anesthesia) Significant trauma related to age Fracture Chronic corticosteroid use Osteoporosis Severe pain after lumbar surgery in past year Infection Fever Urinary tract infectio
22、n Immunosuppression Intravenous drug use The presence of certain signs, termed red flags, indicate the need for further testing to look for more serious underlying problems, which may require immediate or specific treatment. The presence of a red flag does not mean that there is a significant proble
23、m. It is only suggestive, and most people with red flags have no serious underlying problem. If no red flags are present, performing diagnostic imaging or laboratory testing in the first four weeks after the start of the symptoms has not been shown to be useful. Tests The straight leg raise test can
24、 detect pain originating from a herniated disc. When warranted, imaging such as MRI can provide clear detail about disc related causes of back pain (L4L5 disc herniation shown) Imaging is indicated when there are red flags, ongoing neurological symptoms that do not resolve, or ongoing or worsening p
25、ain. In particular, early use of imaging (either MRI or CT) is recommended for suspected cancer, infection, or cauda equina syndrome. MRI is slightly better than CT for identifying disc disease; the two technologies are equally useful for diagnosing spinal stenosis. Only a few physical diagnostic te
26、sts are helpful. The straight leg raise test is almost always positive in those with disc herniation. Lumbar provocative discography may be useful to identify a specific disc causing pain in those with chronic high levels of low back pain. Similarly, therapeutic procedures such as nerve blocks can b
27、e used to determine a specific source of pain. Some evidence supports the use of facet joint injections, transforaminal epidural injections and sacroilliac injections as diagnostic tests. Most other physical tests, such as evaluating for scoliosis, muscle weakness or wasting, and impaired reflexes,
28、are of little use. Management Physical management For acute pain, low- to moderate-quality evidence supports walking. There is tentative evidence to support the use of heat therapy for acute and sub-chronic low back pain but little evidence for the use of either heat or cold therapy in chronic pain.
29、 Exercise therapy is effective in decreasing pain and improving function for those with chronic low back pain. It also appears to reduce recurrence rates for as long as six months after the completion of program and improves long-term function. Medications The management of low back pain often inclu
30、des medications for the duration that they are beneficial. The medication typically recommended first is acetaminophen or NSAIDs (though not aspirin), and these are enough for most people. Standard doses of acetaminophen are very safe; however, very high doses may cause liver problems. NSAIDs are mo
31、re effective for acute episodes than acetaminophen; however, they carry a greater risk of side effects including: kidney failure, stomach ulcers and possibly heart problems. Thus, NSAIDs are a second choice to acetaminophen, recommended only when the pain is not handled by the latter. NSAIDs are ava
32、ilable in several different classes; there is no evidence to support the use of COX-2 inhibitors over any other class of NSAIDs with respect to benefits. Muscle relaxants may also be beneficial. If the pain is still not managed adequately, short term use of opioids such as morphine may be useful. Th
33、ese medications carry a risk of addiction, may have negative interactions with other drugs, and have a greater risk of side effects, including dizziness, nausea, and constipation. Opioids may be suitable for short-term management of severe, acute pain that is causing significant problems. Specialist
34、 groups advise against general long-term use of opioids for chronic low back pain. For older people with chronic pain, opioids may be used in those for whom NSAIDs present too great a risk, such as those with diabetes, stomach or heart problems. Antidepressants may be effective for treating chronic
35、pain associated with symptoms of depression, but they have a risk of side effects. Although the antiseizure drugs gabapentin and carbamazepine are sometimes used for chronic low back pain and may relieve sciatic pain, there is insufficient evidence to support their use. Facet joint injections and st
36、eroid injections into the discs have not been found to be effective in those with persistent, non-radiating pain; however, they may be considered for those with persistent sciatic pain. Epidural corticosteroid injections provide a slight and questionable short-term improvement in those with sciatica
37、 but are of no long term benefit. There are also concerns of potential side effects. Surgery Surgery may be useful in those with a herniated disc that is causing significant pain radiating into the leg, significant leg weakness, bladder problems, or loss of bowel control. It may also be useful in th
38、ose with spinal stenosis. In the absence of these issues, there is no clear evidence of a benefit from surgery. Discectomy (the partial removal of a disc that is causing leg pain) can provide pain relief sooner than nonsurgical treatments. The less invasive microdiscectomy has not been shown to resu
39、lt in a different outcome than regular discectomy. For most other conditions, there is not enough evidence to provide recommendations for surgical options. The long-term effect surgery has on degenerative disc disease is not clear. Less invasive surgical options have improved recovery times. Fusion
40、may be considered for those with low back pain from acquired displaced vertebra that does not improve with conservative treatment. There are a number of different surgical procedures to achieve fusion, with no clear evidence of one being better than the others. Prevention Lifting technique suggested
41、 to avoid low back pain Effective methods to prevent low back pain have not been well developed. Exercise is probably effective in preventing recurrences in those with pain that has lasted more than six weeks. Medium-firm mattresses are more beneficial for chronic pain than firm mattresses. There is little to no evidence that back belts are any more helpful in preventing low back pain than education about proper lifting techniques. Shoe insoles do not help prevent low back pain.
