Treatment of back pain: strategies for drug therapy

A general practitioner consults 20 out of 1,000 people a year for back pain, 10-15% of whom have to be hospitalized. And less than 10% of those hospitalized are offered back pain surgery.

Back pain is an extremely common symptom, affecting 80% of the population of Western Europe at some point in their lives. Of every 1,000 industrial workers, 50 are unable to work each year due to back pain at some point in their lives. In the UK, 11.5 million working days are lost each year due to back pain.

In most cases, back pain goes away on its own: of those who consult a general practitioner, 70% experience improvement within 3 weeks, 90% within 6 weeks, and this does not depend on the treatment the patient receives. However, it should be remembered that back pain can also be a manifestation of a serious illness - a malignant neoplasm, local infection, compression of the spinal cord or equine tail, and, of course, such cases must be diagnosed quickly. The elderly age of the patient forces us to take complaints of back pain more seriously. Thus, according to one study, among patients aged 20 to 55 years complaining of back pain, only 3% were diagnosed with so-called spinal pathology (tumor, infection, inflammatory disease), compared to 11% in people under 20 years old and 19% in people over 55 years old.

Treatments for back pain include:

• treatment of acute back pain;
• bed rest and exercise;
• physical factors;
• medicinal products;
• physiotherapy and procedures;
• surgical intervention;
• back pain prevention training.

Treatment of back pain primarily depends on the nature of the underlying disease. It is divided into undifferentiated and differentiated therapy.

Undifferentiated therapy is aimed at reducing pain syndrome or the patient's reactions to pain and eliminating vegetative reactions. It includes: bed rest until the pain is reduced; local dry heat; reflex-distracting agents (mustard plasters, cupping, ointments); exercise therapy, massage, vitamin therapy, physiotherapy, reflexology, correction of psychological status.

The Importance of Laboratory Tests in the Differential Diagnosis of Back Pain

Deviations	Possible diseases
Increased ESR	Spondyloarthritis, rheumatic polymyalgia, malignant tumors, tuberculosis, osteomyelitis, abscess
Increased alkaline phosphatase activity	Bone metastases, Paget's disease, osteomalacia, primary hyperparathyroidism
Pathological peak on serum protein electropherogram	Myeloma disease
Positive blood culture	Sepsis with development of osteomyelitis or abscess
Detection of prostate specific antigen	Prostate cancer
HLA-B27 detection	Spondyloarthritis
Changes in urine tests	Kidney diseases (stones, tumors, pyelonephritis), Reiter's disease
Positive tuberculin tests	Tuberculosis of bones or spinal cord

Differentiated treatment of back pain of vertebrogenic nature depends on their pathogenetic mechanisms. Complex pathogenetic therapy is aimed at the affected segment, elimination of muscular-tonic manifestations and myogenic trigger zones, foci of neuromyo-osteofibrosis, visceral foci of irritation, autoallergic processes.

In addition, treatment should be differentiated depending on the phase of the disease. In the initial phases or during exacerbation, treatment is aimed at reducing and then completely eliminating the pain syndrome, a significant role in this belongs to immobilization, decongestants, desensitizing, antispasmodic agents, therapeutic drug blockades, special types of massage, vitamin therapy (neuroRubin). The main place is occupied by non-steroidal anti-inflammatory drugs (topical - gels, ointments; oral and parenteral - diclac) and muscle relaxants - tolperisone hydrochloride (mydocalm) intramuscularly 100 mg (1 ml) 2 times a day. After parenteral administration, 150 mg of mydocalm is prescribed 3 times a day orally.

Differential diagnosis of back pain

Signs	Groups of reasons
	Mechanical	Inflammatory	Soft tissue	Focal infiltrative
Start	Variable, often acute	Subacute	Subacute	Gradual
Localization	Diffuse	Diffuse	Diffuse	Focal
Symmetry of the process	Unilateral	Most often bilateral	Generalized	Unilateral or midline
Intensity	Variable	Moderate	Moderate	Expressed
Neurological symptoms	Characteristic	No	No	Usually no
Morning stiffness	Up to 30 min	More than 30 min	Variable	No
Pain response to rest	Weakening	Gain	Variable	No (the pain is constant)
Pain response to physical activity	Gain	Weakening	Variable	No (the pain is constant)
Pain at night	Weak, depends on the position	Moderate	Moderate	Strong
Systemic manifestations	No	Characteristic	No	Possible
Possible diseases	Osteochondrosis, herniated/damaged disc, vertebral fracture, spondylolisthesis	Spondyloarthritis, polymyalgia rheumatica	Fibromyalgia, myofascial syndrome, muscle-ligament strain	Tumor, infection of bones or soft tissues

Upon reaching the stationary phase and the regression phase, other methods acquire leading importance, most of which are related to physiotherapy: manual therapy, stretching, traction treatment, massage, various methods of electrotherapy, acupuncture, local anesthesia, therapeutic gymnastics, various rehabilitation programs: dosed physical and rational motor activity, teaching the patient a new, individually selected motor regimen, the use of bandages, the use of insoles for flat feet. All of them are used in the treatment of similar diseases, and which of them should be preferred is decided by the doctor, and he chooses the method that he is better at.

At different stages of treatment, resorption agents and regeneration stimulants, chondroprotectors (teraflex) are prescribed. Many authors recommend using antidepressants throughout the course of treatment, regardless of the clinical manifestations of depression.

Errors: use of ineffective treatment; inadequate use of time when working with the patient; opioids.

The question of surgical intervention in each specific case is decided jointly with doctors of different specialties: cardiologist, neurologist, rheumatologist, orthopedist and neurosurgeon.

Indications for surgical treatment of neurological complications are divided into absolute and relative. Absolute indications for surgical intervention include: acute compression of the equine tail or spinal cord, irreducible hernia with complete liquorodynamic and myelographic block. Relative indications include unilateral or bilateral pain that does not respond to conservative therapy and leads to disability.

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Signs that may indicate a prognostically severe pathology

Pain caused by physical activity and disappearing after rest is rarely malignant, and vice versa. Alternating or bilateral sciatica, especially if accompanied by sensory symptoms or weakness in the lower limbs or feet, suggests a lesion of the equine tail (urination disorder also supports this).

Anxiety symptoms may also include pain-induced limitation of lumbar spine mobility in all directions, localized bone tenderness to palpation, bilateral neurological "dropout", neurological changes corresponding to the levels of several spinal roots at once (especially if the sacral nerves are involved), bilateral symptoms of spinal root tension (for example, according to the straight leg raise symptom). ESR acceleration (more than 25 mm/h) is a fairly valuable screening test for various serious pathologies.

Patients suspected of having spinal cord or cauda equina compression or experiencing exacerbation of unilateral symptoms should be referred to a specialist immediately, and patients suspected of having cancer or infection should be referred to a specialist without delay.

Treatment for "mechanical" back pain

Most people with back pain are treated conservatively. Patients should rest, lie in a horizontal position or with a slightly straightened back, preferably on a hard mattress (a board can be placed under the mattress). It is necessary to avoid straining the back: the patient should carefully get out of bed, should not bend forward, bend over, stretch upward, sit on low chairs. Analgesics will help break the vicious circle - muscle pain - spasm: for example, paracetamol up to 4 g / day orally, NSAIDs, such as naproxen 250 mg every 8 hours orally after meals, but in acute stages opioids may be required. Heat also helps. If spastic muscle contraction persists, then it is necessary to consider the use of diazepam 2 mg every 8 hours orally. Physiotherapy used in the acute phase of the disease can reduce pain and muscle spasm. The recovering patient should be given instructions on how to stand up and what physical exercises to do to strengthen the back muscles. Many patients prefer to seek help from specialists in bone pathology or chiropractors, but they usually use the same treatment methods as physical therapists. Special observations show that manual therapy can relieve severe pain, but the effect is usually short-lived. If the pain does not go away after 2 weeks, then it is necessary to consider an X-ray examination, epidural anesthesia or a corset. Later, if the pain still persists, it may be necessary to consult a specialist to clarify the diagnosis, increase the effectiveness of treatment measures and to feel confident in your own actions.

Pyogenic infection

It is sometimes quite difficult to make a diagnosis of this type, since there may be no usual signs of infection (fever, local tenderness to palpation, leukocytosis of the peripheral blood), but the ESR is often elevated. Pyogenic infection may be secondary to a primary septic focus. Muscle spasm causes pain and limitation of any movement. About half of these infections are caused by staphylococcus, but Proteus, E. coli, Salmonella typhi and mycobacterium tuberculosis can also cause it. X-rays of the spine reveal rarefaction or erosion of the bone, narrowing of the interarticular space (in one or another joint) and sometimes new bone formation under the ligament. Bone scanning with technetium has the greatest diagnostic value for this pathology. Treatment: as for osteomyelitis, plus bed rest, wearing a corset or plaster "jacket".

Tuberculosis of the spine

Currently, this disease is quite rare in Western Europe. Young people are more often affected. There is pain and limitation of all movements in the back. ESR is usually elevated. In this case, an abscess and compression of the spinal cord may occur. The intervertebral discs are affected in isolation or with the involvement of the vertebral bodies on both the right and left sides, usually the anterior edge of the vertebra is affected first. Radiographs show a narrowing of the affected discs and local osteoporosis of the vertebrae, later bone destruction is detected, which subsequently leads to a wedge-shaped fracture of the vertebra. If the thoracic spine is affected, paraspinal (paravertebral) abscesses may be visible on the radiograph, and kyphosis is also detected during examination of the patient. In case of damage to the lower thoracic or lumbar regions, abscesses may form on the sides of the lumbar muscle (psoas abscess) or in the iliac fossa. Treatment: anti-tuberculosis chemotherapy with simultaneous drainage of the abscess.

Prolapse (protrusion) of the disc in the central direction

The need for urgent neurosurgical intervention should be considered in the presence of bilateral sciatica, perineal or saddle anesthesia, and impaired bowel movement and bladder function.

Urgent decompression is necessary to prevent paralysis of both legs.

Drug therapy for back pain should be combined, taking into account the contribution of nociceptive, neuropathic and psychogenic components; in other words, it is of the utmost importance not only to assess structural changes in the spine, but also to identify the leading pathophysiological mechanisms of pain. In practical terms, it is advisable to consider strategies for differentiated pharmacotherapy depending on structural changes, pathophysiology of pain, mechanisms and targets of drug action and methods of their use.

Drug therapy strategy depending on structural changes

• It is necessary to clarify whether neuropathic pain is caused by transient compression of the root and its swelling, which manifests itself as periodic pain, or by constant compression. In case of transient compression, it is advisable to prescribe a local anesthetic (lidocaine plates), an opioid analgesic and NSAIDs. In case of constant compression of the nerve root, lidocaine plates, tricyclic antidepressants and anticonvulsants are most effective.
• NSAIDs are effective in inflammation of the tissues surrounding the intervertebral disc and in facet syndrome. At the same time, NSAIDs are ineffective in inflammation of the internal sections of the intervertebral disc, since they practically do not penetrate from the blood into these sections (it is appropriate to recall that there are no blood vessels in the intervertebral disc, as well as in other cartilaginous tissues). In this case, the best choice may be an opioid analgesic that affects the central mechanisms of pain. In case of vertebral fractures or during recovery processes after surgical operations, it is undesirable to prescribe NSAIDs, since they inhibit the formation of bone tissue.

Drug therapy strategy based on pain pathophysiology

Analysis of pathophysiological mechanisms allows for more precise selection of medications.

• If there is an obvious inflammatory component, NSAIDs should be recommended. In the case of allodynia, lidocaine patches, anticonvulsants, and antidepressants are indicated. The same medications can be prescribed for sympathetic pain.
• For local muscle hypertonicity, muscle relaxants are effective; for myofascial pain syndrome, local injections of local anesthetics into trigger points are effective.
• With constant activation of NMDA receptors, GABA-mediated inhibition is disrupted. Therefore, GABA-ergic drugs can potentially be effective in relieving pain. Among anticonvulsants, such drugs include topiramate and, to some extent, gabapentin. This group can also include baclofen, which has a GABA-ergic effect at the spinal level.

Drug therapy strategy based on the mechanisms of drug action

• NSAIDs and opioids are more effective in peripheral lesions because the former act on the cascade of proinflammatory reactions, while the latter are able to reduce the release of substance P.
• As already mentioned, anticonvulsants may be useful if neural structures outside the immediate lesion zone are involved. Opioids are most active in the posterior horns of the spinal cord, but it should be remembered that tolerance can develop, mediated by activation of NMDA receptors. To prevent the development of tolerance to opioids, tricyclic antidepressants can be used in small doses, which partially block NMDA receptors.
• GABA receptor agonists can be recommended for increased anxiety and sleep disorders (benzodiazepines, zolpidem). Depression and anxiety are constant "companions" of chronic pain, and antidepressants can be used to relieve them (sertraline, escitalopram, venlafaxine have the best safety profile).

Drug therapy strategy considering different routes of drug administration

Most pain medications are administered orally. However, this is often associated with the risk of systemic side effects, including those from the central nervous system. In this regard, drugs applied locally (for example, lidocaine patches) have an advantage. Another promising method is the use of transdermal systems with an opioid analgesic (in particular, with fentanyl), which provide a slow supply of the drug over a long period of time. Intramuscular and intravenous administration of drugs is usually recommended for patients in hospital. Sometimes intrathecal pumps are implanted for continuous infusion of baclofen and/or opioid analgesics in small doses. This helps to avoid unwanted side effects, but the pump implantation itself is a surgical procedure and may be accompanied by complications. In conclusion, it should be noted that at present, the main principle of drug therapy for back pain is rational polypharmacotherapy. It is not always possible to relieve pain with just one drug. When prescribing medications, it is important to maintain a balance between their effectiveness and the risk of adverse effects, and in combination therapy, to take into account the possibility of their interaction.