Low back pain

[BSHC]

Low back pain

Low back pain or lumbago ( /lʌmˈbeɪɡoʊ/)

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.

 Classification

Lower back pain may be classified by the duration of symptoms as

acute (less than 4 weeks),

sub acute (4–12 weeks),

chronic (more than 12 weeks).^[2]

 Cause

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
  • Sacroiliac Joint Dysfunction
  • 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
  • Sacroiliitis

• 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

 Pathophysiology

The lumbar region in regards to the rest of the spine.

The lumbar region (or lower back region) is made up of five vertebrae (L1-L5). In between these vertebrae lie fibrocartilage discs (intervertebral discs), which act as cushions, preventing the vertebrae from rubbing together while at the same time protecting the spinal cord. Nerves stem from the spinal cord through foramina within the vertebrae, providing muscles with sensations and motor associated messages. Stability of the spine is provided through ligaments and muscles of the back, lower back and abdomen. Small joints which prevent, as well as direct, motion of the spine are called facet joints (zygapophysial joints).^[6]

Causes of lower back pain are varied. Most cases are believed to be due to a sprain or strain in the muscles and soft tissues of the back.^[3] Overactivity of the muscles of the back can lead to an injured or torn ligament in the back which in turn leads to pain. An injury can also occur to one of the intervertebral discs (disc tear, disc herniation). Due to aging, discs begin to diminish and shrink in size, resulting in vertebrae and facet joints rubbing against one another. Ligament and joint functionality also diminishes as one ages, leading to spondylolisthesis, which causes the vertebrae to move much more than they should. Pain is also generated through lumbar spinal stenosis, sciatica and scoliosis. At the lowest end of the spine, some patients may have tailbone pain (also called coccyx pain or coccydynia). Others may have pain from their sacroiliac joint, where the spinal column attaches to the pelvis, called sacroiliac joint dysfunction which may be responsible for 22.6% of low back pain.^[7] Physical causes may include osteoarthritis, rheumatoid arthritis, degeneration of the discs between the vertebrae or a spinal disc herniation, a vertebral fracture (such as from osteoporosis), or rarely, an infection or tumor^[8] .

In the vast majority of cases, no noteworthy or serious cause is ever identified. If the pain resolves after a few weeks, intensive testing is not indicated.^[9]

 Diagnostic approach

Typically people are treated symptomatically without exact determination of the underlying cause. Only in cases with worrisome signs is diagnostic imaging needed.

 Imaging

X-rays, CT or MRI scans are not required in lower back pain except in the cases where "red flags" are present.^[10] If the pain is of a long duration X-rays may increase patient satisfaction.^[11] However routine imaging may be harmful to a person's health and more imaging is associated with higher rates of surgery but no resultant benefit.^[12] From 1994 to 2006, in the United States MRI scans of the lumbar region increased by more than 300%.^[13]

 Red flags

• Recent significant trauma
• Milder trauma if age is greater than 50 years
• Unexplained weight loss
• Unexplained fever
• Immunosuppression
• Previous or current cancer
• Intravenous drug use
• Osteoporosis
• Chronic corticosteroid use
• Age greater than 70 years
• Focal neurological deficit
• Duration greater than 6 weeks^[14]

 Risks of imaging

Complaints of lower back pain are one of the most common reasons why people visit doctors.^[15] Although many patients and doctors try to find the cause of the pain with imaging tests such as an X-ray, CT scan, or MRI, in most cases these tests are not necessary.^[15] Most people with lower-back pain feel better after a month regardless of whether they get imaging.^[15] Fewer than 1% of imaging tests identify the cause of a problem.^[15]

The negative effects of imaging include the following:

• The tests rarely result in a faster or better recovery^[15]
• X-rays and CT scans expose the patient to harmful radiation^{[citation needed]}
• They can detect harmless abnormalities which encourage the patient to request further unnecessary testing or to worry^[15]
• Testing for acute back pain often leads to unnecessary surgery^[15]
• The tests are expensive^[15]

Medical societies do not recommend imaging tests for lower back pain within a few weeks of the onset of pain as the pain is likely to subside.^[15]

 Prevention

Exercise is effective in preventing recurrence of non-acute pain, however has shown mixed results in the treatment of acute episodes.^[16] Proper lifting techniques may be useful.^[17]

Cigarette smoking impacts the success and proper healing of spinal fusion surgery in patients who undergo cervical fusion; rates of nonunion are significantly greater for smokers than for nonsmokers.^[18] Smoke and nicotine accelerate spine deterioration, reduce blood flow to the lower spine, and cause discs to degenerate.^[19]

 Management

 Acute pain

Self care

For acute cases that are not debilitating, low back pain may be best treated with conservative self-care,^[20] including: application of heat or cold,^[21][22] and continued activity within the limits of the pain.^[23][24] Firm mattresses have demonstrated less effectiveness than medium-firm mattresses.^[25]

Engaging in physical activity within the limits of pain aids recovery. Prolonged bed rest (more than 2 days) is considered counterproductive.^[23][26] Even with cases of severe pain, some activity is preferred to prolonged sitting or lying down - excluding movements that would further strain the back.^[9] Structured exercise in acute low back pain has demonstrated neither improvement nor harm.^[16]

Physical therapy

Physical therapy can include heat, ice, massage, ultrasound, and electrical stimulation. Active therapies can consist of stretching, strengthening and aerobic exercises. Exercising to restore motion and strength to your lower back can be very helpful in relieving pain and preventing future episodes of low back pain.^[27]

Medications

Short term use of pain and anti-inflammatory medications, such as NSAIDs or acetaminophen may help relieve the symptoms of lower back pain.^[26][28] NSAIDs are slightly effective for short-term symptomatic relief in patients with acute and chronic low-back pain without sciatica.^[29] Muscle relaxants for acute^[26] and chronic^[28] pain have some benefit,^[30] and are more effective in relieving pain and spasms when used in combination with NSAIDs.^[31]

Spinal manipulation

It is not known if chiropractic care improves clinical outcomes in those with lower back pain more or less than other possible treatments.^[32] A 2004 Cochrane review found that spinal manipulation (SM) was no more or less effective than other commonly used therapies such as pain medication, physical therapy, exercises, back school or the care given by a general practitioner^[33] which was supported by a 2006 and 2008 review.^[34][35] A 2010 systematic review found that most studies suggest SM achieves equal or superior improvement in pain and function when compared with other commonly used interventions for short, intermediate, and long-term follow-up.^[36] In 2007 the American College of Physicians and the American Pain Society jointly recommended that it be considered for people who do not improve with self care options.^[20] A 2007 literature synthesis found good evidence supporting SM and mobilization for low back pain.^[37]

 Chronic pain

Low back pain is more likely to be persistent among people who previously required time off from work because of low back pain, those who expect passive treatments to help, those who believe that back pain is harmful or disabling or fear that any movement whatever will increase their pain, and people who have depression or anxiety.^[9] A number of factors predict disability from back pain and include thsoe who have poor coping behaviors or who fear activity are about 2.5 times as likely to have poor outcomes at a year.^[38]

The following measures have been found to be effective for chronic non-specific back pain:

• Exercise therapy appears to be slightly effective at reducing pain and improving function in the treatment of chronic low back pain.^[39] Compared to usual care, exercise therapy improved post-treatment pain intensity and disability, and long-term function.^[40] Exercise programmes are effective for chronic LBP up to 6 months after treatment cessation, evidenced by pain score reduction and reoccurrence rates.^[41] There is no evidence that one particular type of exercise therapy is clearly more effective than others.^[42] The Schroth method, a specialized physical exercise therapy for scoliosis, kyphosis, spondylolisthesis, and related spinal disorders, has been shown to reduce severity and frequency of back pain in adults with scoliosis.^[43]
• Tricyclic antidepressants are recommended in a 2007 guideline by the American College of Physicians and the American Pain Society.^[44]
• Acupuncture may help chronic pain;^[28] however, a more recent randomized controlled trial suggested insignificant difference between real and sham acupuncture.^[45]
• Intensive multidisciplinary treatment programs may help subacute^[26] or chronic^[28] low back pain.^[9]
• Behavioral therapy^[28]
• The Alexander Technique was shown in a UK clinical trial to have long-term benefits for patients with chronic back pain.^[46]
• Spinal manipulation has been shown to have a clinical effect equal to that of other commonly used therapies and was considered safe.^[47]
• Treatment according to McKenzie method is somewhat effective for acute low back pain, but the evidence suggests that it is not effective for chronic low-back pain.^[48]
• Manipulation under anaesthesia, or medically-assisted manipulation, currently has insufficient evidence to make any strong recommendations.^[49]
• Prolotherapy, facet joint injections, and intradiscal steroid injections have not been found to be effective.^[50]

Epidural corticosteroid injections provide slight temporary relief of sciatica however have no long term benefit.^[51]Traditional Chinese Medical acupuncture was proven to be relatively ineffective for chronic back pain.^[52]

 Surgery

Surgery may be indicated when conservative treatment is not effective in reducing pain or when the patient develops progressive and functionally limiting neurologic symptoms such as leg weakness, bladder or bowel incontinence, which can be seen with severe central lumbar disc herniation causing cauda equina syndrome or spinal abscess.^{[citation needed]} Spinal fusion has been shown not to improve outcomes in those with simple chronic low back pain.^[53]

The most common types of low back surgery include microdiscectomy, discectomy, laminectomy, foraminotomy, or spinal fusion. Another less invasive surgical technique consists of an implantation of a spinal cord stimulator and typically is used for symptoms of chronic radiculopathy (sciatica). Lumbar artificial disc replacement is a newer surgical technique for treatment of degenerative disc disease, as are a variety of surgical procedures aimed at preserving motion in the spine. According to studies, benefits of spinal surgery are limited when dealing with degenerative discs.^[54]

A medical review in March 2009 found the following: Four randomised clinic trials showed that the benefits of spinal surgery are limited when treating degenerative discs with spinal pain (no sciatica). Between 1990 and 2001 there was a 220% increase in spinal surgery, despite the fact that during that period there were no changes, clarifications, or improvements in the indications for surgery or new evidence of improved effectiveness of spinal surgery. The review also found that higher spinal surgery rates are sometimes associated with worse outcomes and that the best surgical outcomes occurred where surgery rates were lower. It also found that use of surgical implants increased the risk of nerve injury, blood loss, overall complications, operating times and repeat surgery while it only slightly improved solid bone fusion rates. There was no added improvement in pain levels or function.^[55]

The logic behind spinal fusion is that by fusing two vertebrae together, they will act and function as a solid bone. Since lumbar pain may be caused by excessive motion of the vertebra the goal of spinal fusion surgery is to eliminate that extra motion in between the vertebrae, alleviating pain. If scoliosis or degenerative discs is the problem, the spinal fusion process may be recommended. There are several different ways of performing the spinal fusion procedure; however, none are proven to reduce pain better than the others.^[27]

 Other

Additional treatments have been more recently reviewed by the Cochrane Collaboration:

• Massage therapy may benefit some patients.^[56]
• Heat application may have a modest benefit. The evidence for cold therapy is limited.^[57]
• Yoga has been found beneficial.^[58][59][60]
• Correcting leg length difference may help by inserting a heel lift or building up the shoe.^[61]
• The role of narcotics for chronic low back pain is uncertain.^[62]
• Antidepressants appear ineffective in the treatment of chronic back pain^[63] even though some previous studies found them helpful.^[28]
• Transcutaneous electrical nerve stimulation (TENS) has not been found to be effective in chronic lower back pain.^[64]

 Prognosis

Most people with acute lower back pain recover completely over a few weeks regardless of treatments.^[65][66] At 6 weeks complete recovery rates have been reported at between 40-90%.^[67] For those whose low back pain continues on to chronicity, it is rarely self limiting, as fewer than 10% of those whose low back pain becomes chronic report no pain five years later.^[68]

 Epidemiology

Over a lifetime 80% of people have lower back pain,^[66] with 26% of American adults reporting pain of at least one day in duration every three months.^[69] 41% of adults aged between 26 and 44 years reported having back pain in the previous 6 months. In the United States, estimates of the costs of low back pain range between $38 and $50 billion a year and there are 300,000 operations annually. Along with neck operations, back operations are the 3rd most common form of surgery in the United States.^[70]

 In pregnancy

An estimated 50-70% of pregnant women experience back pain.^[71]

As one gets farther along in the pregnancy, due to the additional weight of the fetus, one’s center of gravity will shift forward causing one’s posture to change. This change in posture leads to increasing lower back pain.^[71][72]

The increase in hormones during pregnancy is in preparation for birth. This increase of hormones softens the ligaments in the pelvic area and loosens joints. This change in ligaments and joints may alter the support to which one’s back is normally accustomed.^[73][74]