Back pain, a leading cause of disability worldwide , is characterized by a dull ache or a piercing pain in the back. It may arise from the muscles, nerves, bones, joints or other structures in the spine.
Back pain is classified based on three criteria:
1) Duration: Episodes of back pain may be acute, sub-acute, or chronic, where acute pain lasts up to 12 weeks, sub-acute pain for 6 to 12 weeks and chronic pain persists beyond 12 weeks.
2) Origin: Back pain is classified anatomically based on the segment of the spine from where the pain is originated. Neck pain originates from the cervical region, middle back pain from the thoracic region, lower back pain from the lumbar region and coccydynia from the sacral region of the spine.
3) Cause: Based on the cause of the pain, the classification is as follows: Non-specific back pain is defined as low back pain which is not attributed to any known specific pathology but is believed to be from soft tissues such as muscles or fascia. Radicular pain involves pain in the nervous tissue and secondary back pain results from an already existing medical condition such as cancer. 
The most common form of back pain is the non-specific acute lower back pain. Low back pain (LBP) is a very common health problem contributing to voluminous medical consultations each year and affects all ranges of the population. The Global Burden of Disease Study (GBD) 2010 shows that LBP is amongst the top ten high-burden diseases and injuries, with an average number DALYs (disability-adjusted life years) higher than that of HIV, road injuries, lung cancer and chronic obstructive pulmonary disease.
Globally, and out of 291 conditions, LBP was ranked as the greatest contributor to global disability and sixth in terms of overall burden . It was also the leading cause of activity limitation and work absence throughout much of the world, and thus resulting in an enormous economic burden on individuals, families, industries and governments .
Symptoms include shooting pain, muscle ache, limited flexibility and an inability to stand upright. It is mostly progressive and the cause can be difficult to determine . Low back pain may be felt as a burning, stabbing pain-sharp or dull, well-defined or vague with varying intensity .
Warning signs — Serious symptoms include severe back pain with fever, bowel/bladder incontinence, weight loss, appetite loss and progressive weakness. Pain that radiates into the hands and legs, accompanied by numbness, tingling or paralysis may be a sign of potential damage to the nerves that exit the spinal cord. Individuals with medical conditions such as osteoporosis, multiple myeloma or cancer experiencing back pain need prompt medical attention and those individuals with a history of cancer should be carefully examined to eliminate the metastatic disease of the spine .
Back pain may be caused due to various reasons, majority of which are not serious or debilitating. This accounts to almost 98% of back pain patients who experience nonspecific acute back pain to which a specific cause cannot be attributed. Approximately 2% are comprised by metastatic cancers, while serious infections such as spinal osteomyelitis and epidural abscesses account for less than 1%. Studies suggest that low back pain may arise from any of a number of anatomical structures, including bones, intervertebral discs, ligaments, muscles, neural structures and blood vessels. In only a few instances, low back pain can be attributed to a specific cause such as an osteoporotic fracture, neoplasm or infection. 
The major causes include:
Ø Conditions such as a spinal disc herniation, degenerative disc disease, isthmic spondylolisthesis, sciatica, osteoarthritis, lumbar spinal stenosis, cancer, infection and inflammatory disease.
Ø Trauma (such as a car accident/fall) may indicate a bone fracture or other injury.
Ø Psychosocial factors such as on-the-job stress and dysfunctional family relationships.
Ø Other factors that can cause low back pain include: individual characteristics, lifestyle factors, working conditions such as heavy physical work, awkward static and dynamic working postures, as well as manual handling and lifting .
Both environmental and personal factors influence the onset and course of back pain. Some of them include:
Ø Socio-demographic factors: Lifestyle factors, such as smoking and physical conditioning are potential risk factors for low back pain. Modifiable factors also include lack of exercise, obesity and high body weight.
Ø Psychosocial factors: People with low levels of social support in the workplace, high psychological demands and work dissatisfaction as well as stress, anxiety, depression are more prone to low back pain.
Ø Occupational factors: People who are subjected to vibrations or long standing positions such as health-care workers, occupational drivers, and construction workers are more predisposed to to LBP .
Ø Other risk factors such as gender, age, and genetics are not modifiable. About 50% of women experience low back pain during pregnancy and hence extra care and preventive measures must be taken to avoid back pain during pregnancy.
Prior to imaging studies, patient history is studied and a brief physical examination is done to exclude any serious disorders causing the pain (eg ., tumor, infection, fracture). Low back pain can be classified based on the pain distribution, pain behavior, functional disability and clinical signs. Clinical examination is followed by diagnosis through imaging techniques which include the following:
· X-ray images reveal the alignment of bones and are useful in detecting any broken bones or other skeletal defects.
· MRI and CT scans can reveal disc ruptures, tumours or problems with bones, muscles, tissue, tendons, nerves, ligaments and blood vessels.
· Bone scans are done to detect any bone tumors or compression fractures caused by osteoporosis.
· Blood tests can help detect an infection or other conditions causing the pain.
· Nerve studies using electromyography measure electrical nerve impulses and responses from muscles. Such studies can confirm spinal stenosis or nerve compression caused by herniated disks .
PREVENTION AND TREATMENT
Back pain may be prevented by various physical and educational interventions. Many work-related injuries heightened by stressors such as heavy lifting, repetitive motion and awkward posture can be avoided by applying ergonomic principles in the workplace .
Currently, the main treatment goal for low back pain is to minimize the pain and sustain function. Treatment usually involves using pain relievers and anti-inflammatory drugs to reduce pain and inflammation. Some of the several ways to alleviate pain are as follows:
· Medications: Analgesics such as paracetamol, NSAIDs (Nonsteroidal anti-inflammatory drug) and opioids can treat low back pain. The difficulty is to manage pain when it becomes chronic because of the long-term side events of these medicines. Acetominophen (such as tylenol) and muscle relaxants also effectively provide pain relief.
Also, small doses of tricyclic antidepressants can help regulate sleep cycles. Some of these medications are available over-the-counter (OTC) while others require a physician’s prescription. Creams, gels, ointments, patches, and sprays may relieve pain and inflammation of the skin.
To treat depression, sleep disorders, pain.
Dizziness, head ache, weight gain, constipation.
Relieves pain and inflammation.
Headache, dizziness, increased pain.
Reduces muscle spasms, pain and improves muscle mobility.
Possible side effects: drowsiness, addiction, dry mouth, urinary retention.
Relieves pain and inflammation
Long-term use: stomach irritation, diarrhea, kidney dysfunction.
Treats severe pain
Long-term use: addiction, drowsiness, constipation.
· Heat therapy: It is useful for back spasms and can reduce symptoms of acute and sub-acute low back pain. Exposure to moist heat (e.g. a hot bath) or continuous low-level heat (e.g. heat wrap) can help lessen the pain.
· Other options: Massages may give short-term pain relief, but not functional improvement. Supervised exercises can also be an effective approach to reduce pain. Essentially, non-drug approaches such as massages, ultrasounds, electrotherapy, laser and traction can substantially improve the treatment of low back pain only in certain cases. Typically, the management of low back pain involves musculoskeletal rearrangement through manipulations by physiotherapists, chiropractors or exercise therapists.
Only in the most serious cases, when all other treatments fail, surgery is done. The main back pain surgeries include discetomies, spinal fusions, laminectomies, removal of tumors, and vertebroplasties.
· Nerve decompression is primarily performed in older patients suffering from conditions causing nerve irritation or nerve damage.
· Spinal fusion, a procedure commonly performed to treat intervertebral disc herniations and degenerated discs is done to fuse together two or more bony fragments with the help of metalwork.
· Deformity correction surgeries are performed to correct congenital deformities or deformities caused by a traumatic fracture.
· A discectomy performed in case of a herniated intervertebral disc, involves removing the protruding disc that is placing pressure on the nerve root.
· In cases of spinal stenosis and disc herniation, laminectomy can also be performed to reduce pressure on the nerves, thereby relieving some pain.
· Back surgeries are done to prevent the growth of benign and malignant tumors.
Other treatment options such as:(i) Implantation of mechanical prostheses,(ii) Intradiscal injections of steroids or glucocorticoids to treat discogenic pain,(iii) Neuro-reflexotherapy intervention (NRT) (defined as the temporary implantation of epidermal devices in trigger points defined by their innervations to desensitize neurons) also exist. 
Hindrances to treatment: Hence, fundamentally there is no standard curefor most cases of back pain. Compared to other medical conditions, there are relatively few standardized approaches to treatment of back problems and so spine specialists will often disagree or have differing opinions on the diagnosis and the appropriate treatment plan. However, diagnoses and treatment for few conditions are relatively straightforward (eg., spinal tumor, infection, or fracture).
Back pain has a substantial impact on individuals and their families, communities, health-care systems and businesses. This includes pain, activity limitations, career burden and enormous financial burden which includes the costs of medical care, productivity loss, employee retraining, administrative expenses, etc.,
Fig.1: Map of annual years of healthy life lost due to low back pain across countries. Worldwide, Germany, Sweden, and Switzerland are the top three countries that lost healthy lives from low back pain in 2013, respectively. (Source: Global-diseases.healthgrove.com, 2017)
· Downside of human evolution: Researchers put forth an evolutionary perspective stating that the modifications in the human spine because of our upright posture may have led to unique back pains. For instance, although walking upright freed up our hands for tool use, the subsequent stresses on the human spine may have resulted in back pain. 
· Several celebrities such as George W. Bush, Jackie Chan and George Clooney have also combated back pain which has hindered their career. Usain Bolt, the fastest man on earth suffered from scoliosis (curvature of the spine) which led him to missing out on the 2010 track season .
· President John F. Kennedy’s back surgery: President Kennedy suffered from back pain throughout his life and underwent spine surgery in 1954 that nearly killed him. He underwent several surgical procedures for back pain and continued to receive conservative care for the rest of his life .
CURRENT STUDIES AND FUTURE WORK
While current treatments for back pain only offer palliative care to help mobility and reduce pain, recent advances such as stem cell therapy provide a new, alternative hope for back pain treatment. One of the fast growing research areas is the application of stem cells and biomaterials in low back pain therapy. Other studies in the area of prostheses involve the development of more resistant materials and 3D imaging technologies to investigate improved surgical options for disc replacement. Researchers also examine different health care approaches to the management of acute low back pain (standard care versus chiropractic, acupuncture, or massage therapy). The following information highlights some of the on-going research work conducted on back pain treatment:
· Research work on intervertebral disc (IVD) regeneration:
Alternative approaches for tackling biologic repair and regeneration of IVD such as cell transplantation, administration of growth factors, gene therapy and tissue regeneration are being studied currently.
· A solution to repair the degenerated disc and restore its function by the introduction of functional cells and supporting biomaterials is a recent focus.
· Another way for disc regeneration is the injection of molecules such as growth factors, inflammatory cytokine antagonists, etc., into the IVD to aid regeneration.
· Replacing the altered annulus fibrosus instead of the entire disc by injecting shock absorbing materials as an alternative is also being explored.
· Mesenchymal stem cells (MSCs) may be ideal candidates for disc regeneration because of their high proliferation rate and potential for multi-lineage differentiation. Since autologous transplant eliminates the risk of immunoreaction and shows promising results in terms of improvement of pain, several approaches are being investigated to improve the survival of the injected MSC.
Various institutions and agencies conduct research aiming to improve the management of back pain. The European Union proposes guidelines that are intended to offer guidance on diagnosis and treatment of chronic non-specific low back pain. A research project called Genodisc, being funded by the European Commission aims to explore different areas such as (a) searching for biomarkers (b) searching for anthropometric risk factors and adapted rehabilitation(c) development of biomaterials and (d) stem cell research to improve the treatment options of low back pain .
The National Institute of Neurological Disorders and Stroke (NINDS) and other NIH institutes perform pain research and also support research of other major institutions through grants. The National Center for Complementary and Integrative Health (NCCIH) funds and conducts research to understand more about complementary and integrative health approaches that may help in treating chronic pain. Their objective is to play a key role not only in determining the value of nondrug approaches and self-management strategies but also in understanding the neuroscience of pain .
Back pain, a disorder with a constellation of symptoms is both a major cause of disability and a challenge to medical and surgical treatment decisions. It causes enormous socio-economic impacts on societies, and treatments, for now, are still focused on reducing the pain. The management of patients with low back pain requires several interventions, close monitoring of potential complications, and appropriate rehabilitation by trained professionals.
As the current world population ages, the burden of low back pain will increase substantially. Since surgery and disc replacements remain at present the last option to relieve pain when all other strategies fail, novel developments in 3D imaging, biomaterials and stem cell therapies may bring new hope for the treatment of back pain. Further research is needed to help us understand more about the broader outcomes and impacts of back pain.
Disability-adjusted life years
Global Burden of Disease
Low back pain
Magnetic resonance imaging
Mesenchymal stem cells
National Center for Complementary and Integrative Health
National Institutes of Health
National Institute of Neurological Disorders and Stroke
Non-steroidal anti-inflammatory drug
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Dr. Sukant Khurana runs an academic research lab and several tech companies. He is also a known artist, author, and speaker. You can learn more about Sukant at www.brainnart.com or www.dataisnotjustdata.com and if you wish to work on biomedical research, neuroscience, sustainable development, artificial intelligence or data science projects for public good, you can contact him at firstname.lastname@example.org or by reaching out to him on linkedin https://www.linkedin.com/in/sukant-khurana-755a2343/.