Lower back pain

In domestic literature, the term “lumbago” is sometimes used for pain in the lower back, “lumbosciatica” for pain localized in the lumbar region and leg, and “lumbosacral radiculitis” (radiculopathy) in the presence of signs of damage to the lumbar roots.

In addition, often when pain is localized in any area of the back, with the exception of the cervical-shoulder area or a combination of several painful areas of the back, one can come across the term "dorsalgia" or "dorsopathy". In this case, the term "dorsopathy" defines a pain syndrome in the trunk and limbs of non-visceral etiology associated with degenerative diseases of the spine.

The term "lower back pain" refers to pain, muscle tension or stiffness localized in the back area between the 12th pair of ribs and the gluteal folds, with or without irradiation to the lower limbs.

What causes lower back pain?

Lower back pain as a clinical manifestation occurs in almost a hundred diseases, and perhaps for this reason, there is no generally accepted classification of pain sensations in this localization. The source of pain impulses in this area can be almost all anatomical structures of the lumbosacral region, abdominal cavity and pelvic organs.

Based on pathophysiological mechanisms, the following types of lower back pain are distinguished.

• Nociceptive pain in the lower back occurs when pain receptors - nociceptors - are excited due to damage to the tissues in which they are located. Accordingly, the intensity of nociceptive pain sensations, as a rule, depends on the degree of tissue damage and the duration of exposure to the damaging factor, and its duration on the characteristics of the healing processes. Pain in the lower back can also occur with damage or dysfunction of the structures of the central nervous system and / or peripheral nervous system involved in the conduction and analysis of pain signals, i.e. with damage to nerve fibers at any point from the primary afferent conduction system to the cortical structures of the central nervous system. It persists or occurs after the healing of damaged tissue structures, so it is almost always chronic and does not have protective functions.
• Neuropathic pain is pain in the lower back that occurs when peripheral structures of the nervous system are damaged. Central pain occurs when structures of the central nervous system are damaged. Sometimes neuropathic back pain is divided into radicular (radiculopathy) and non-radicular (sciatic nerve neuropathy, lumbosacral plexopathy).
• Psychogenic and somatoform lower back pain occurs regardless of somatic, visceral or neurological damage and is determined primarily by psychological factors.

The most widely accepted scheme in our country is one that divides lower back pain into two categories: primary and secondary.

Primary lower back pain is a pain syndrome in the back caused by degenerative and functional changes in the tissues of the musculoskeletal system (facet joints, intervertebral discs, fascia, muscles, tendons, ligaments) with possible involvement of adjacent structures (roots, nerves). The main causes of primary lower back pain syndrome are mechanical factors, determined in 90-95% of patients: dysfunction of the muscular-ligamentous apparatus; spondylosis (in foreign literature this is a synonym for osteochondrosis of the spine): intervertebral disc herniation.

Secondary lower back pain is caused by the following reasons:

• congenital anomalies (lumbarization, spina bifida, etc.);
• injuries (vertebral fractures, protrusions of intervertebral discs, etc.);
• arthritis (Bechterew's disease, reactive arthritis, rheumatoid arthritis, etc.);
• other diseases of the spine (tumors, infections, metabolic disorders, etc.);
• projection pain in diseases of internal organs (stomach, pancreas, intestines, abdominal aorta, etc.);
• diseases of the genitourinary organs.

On the other hand, A.M. Wayne divided the causes into two large groups: vertebrogenic and non-vertebrogenic.

Vertebrogenic causes of lower back pain, in descending order of frequency, included:

• prolapse or protrusion of the intervertebral disc;
• spondylosis;
• osteophytes;
• sacralization, lumbalization;
• facet syndrome;
• ankylosing spondylitis;
• spinal stenosis;
• instability of the vertebral motion segment;
• vertebral fractures;
• osteoporosis (due to fractures);
• tumors;
• functional disorders.

Among the non-vertebrogenic causes are named:

• myofascial pain syndrome:
• psychogenic pain;
• reflected pain in the lower back due to diseases of the internal organs (heart, lungs, gastrointestinal tract, genitourinary organs);
• epidural abscess;
• metastatic tumors;
• syringomyelia;
• retroperitoneal tumors.

Based on duration, lower back pain is divided into:

• acute (up to 12 weeks);
• chronic (over 12 weeks).

The following stands out separately:

• recurrent lower back pain occurring at intervals of at least 6 months after the end of the previous exacerbation;
• exacerbation of chronic lower back pain, if the specified interval is less than 6 months.

Based on specificity, lower back pain is divided into:

• specific;
• non-specific.

In this case, non-specific lower back pain is usually such an acute pain that it is impossible to make an exact diagnosis and there is no need to strive for it. In turn, specific lower back pain is defined in cases where painful sensations are a symptom of a certain nosological form, often threatening the patient's future health and/or even life.

Epidemiology

Lower back pain is one of the most common complaints of patients in general medical practice. According to a number of researchers, 24.9% of active requests for outpatient care by people of working age are associated with this condition. Particular interest in the problem of lower back pain is primarily due to its widespread prevalence: at least 80% of the adult population of the world experiences this pain at least once in their life; approximately 1% of the population is chronically disabled and twice as many are temporarily disabled due to this syndrome. At the same time, a decrease in working capacity in the presence of pain is noted by more than 50% of patients. The total disability of patients - mainly people of working age - in turn leads to significant material losses and costs for diagnostics, treatment and rehabilitation and, as a result, to significant health care costs and a negative impact on the national economy.

At present, only a few epidemiological studies of lower back pain have been conducted, mostly concerning organized groups. Thus, a study of workers and employees of a medium-sized machine-building plant in 1994-1995 showed that 48% of respondents complained of lower back pain during their life, 31.5% in the last year, and 11.5% at the time of the survey, without significant differences between men and women. A high prevalence of lower back pain was found among workers in motor transport (2001) and a metallurgical plant (2004): 43.8 and 64.8%, respectively. The problem of lower back pain concerns not only the adult population, it is found in 7-39% of adolescents.

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How does lower back pain manifest itself?

Lower back pain has virtually no differences in its characteristics from other types of pain, except for its localization. As a rule, the nature of the pain is determined by the organs or tissues whose pathology or damage led to its appearance, neurological disorders, as well as the psycho-emotional state of the patient.

Clinically, three types of back pain should be distinguished:

• local:
• projected;
• reflected.

Local pain occurs at the site of tissue damage (skin, muscles, fascia, tendons and bones). They are usually characterized as diffuse and are constant. Most often, they include musculoskeletal pain syndromes, among which are:

• muscular-tonic syndrome;
• myofascial pain syndrome;
• arthropathy syndrome:
• segmental instability syndrome of the spine.

Muscular tonic syndrome

It usually occurs after prolonged and isometric muscle tension due to a certain motor stereotype, exposure to cold, or pathology of internal organs. A prolonged muscle spasm, in turn, leads to the appearance and intensification of pain, which intensifies the spastic reaction, which further intensifies the pain, etc., that is, the so-called "vicious circle" is launched. Most often, muscle-tonic syndrome occurs in the muscles that straighten the spine, in the piriformis and gluteus medius muscles.

Myofascial pain syndrome

It is characterized by local non-specific muscle pain caused by the occurrence of foci of increased irritability (trigger points) in the muscle, and it is not associated with damage to the spine itself. Its causes may be, in addition to congenital skeletal abnormalities and prolonged muscle tension in antiphysiological positions, trauma or direct compression of muscles, their overload and stretching, as well as pathology of internal organs or mental factors. The clinical feature of the syndrome, as has already been said, is the presence of trigger points corresponding to zones of local muscle compaction - areas in the muscle, the palpation of which provokes pain in an area remote from pressure. Trigger points can be activated by an "unprepared" movement, a minor injury to this area, or other external and internal effects. There is an assumption that the formation of these points is due to secondary hyperalgesia against the background of central sensitization. In the genesis of trigger points, damage to peripheral nerve trunks is not excluded, since anatomical proximity has been noted between these myofascial points and peripheral nerve trunks.

The following criteria are used to diagnose the syndrome.

Major criteria (all five must be present):

• complaints of regional pain in the lower back;
• palpable "tight" band in the muscle;
• an area of increased sensitivity within the “tight” cord;
• characteristic pattern of reflected pain or sensory disturbances (paresthesia);
• limitation of range of motion.

Minor criteria (one of three is enough):

• reproducibility of pain sensations or sensory disturbances during stimulation (palpation) of trigger points;
• local contraction upon palpation of the trigger point by them during injection of the muscle of interest;
• reducing pain from muscle strain, therapeutic blockade or dry needling.

A classic example of myofascial pain syndrome is piriformis syndrome.

Arthropathic syndrome

The source of pain in this syndrome is the facet joints or sacroiliac joints. Usually this pain is mechanical in nature (increases with exertion, decreases at rest, its intensity increases towards evening), especially it is increased by rotation and extension of the spine, which leads to localized pain in the area of the affected joint. Pain in the lower back can radiate to the groin area, coccyx and outer surface of the thigh. A positive effect is provided by blockades with a local anesthetic in the projection of the joint. Sometimes (approximately up to 10% of cases) arthropathic pain in the lower back is of an inflammatory nature, especially in the presence of spondyloarthritis. In such cases, patients complain, in addition to "blurred" pain in the lumbar region, of limited movement and stiffness in the lumbar region, expressed to a greater extent in the morning.

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Segmental instability syndrome of the spine

Lower back pain in this syndrome occurs due to the displacement of the body of a vertebra relative to the axis of the spine. It occurs or intensifies with prolonged static load on the spine, especially when standing, and often has an emotional coloring, defined by the patient as "fatigue in the lower back". Often this lower back pain is encountered in people with hypermobility syndrome and in middle-aged women with signs of moderate obesity. As a rule, with segmental instability of the spine, flexion is not limited, but extension is difficult, in which patients often resort to the help of their hands, "climbing up themselves."

Reflected pain is pain in the lower back that occurs when there is damage (pathology) to internal organs (visceral somatogenic) and is localized in the abdominal cavity, small pelvis, and sometimes in the chest. Patients feel this pain in the lower back in those areas that innervate the same segment of the spinal cord as the affected organ, for example, in the lumbar region with an ulcer of the posterior wall of the stomach, dissecting aneurysm of the abdominal aorta, pancreatitis, etc.

Projected pains are widespread or precisely localized in nature, and by the mechanism of their occurrence they are classified as neuropathic. They occur when the nerve structures that conduct impulses to the pain centers of the brain are damaged (for example, phantom pains, pains in areas of the body innervated by the compressed nerve). Radicular, or radicular, pain in the lower back is a type of projected pain, usually of a shooting nature. They can be dull and aching, but movements that increase irritation of the roots significantly increase the pain: it becomes sharp, cutting. Almost always, radicular pain in the lower back radiates from the spine to some part of the lower limb, most often below the knee joint. Bending the body forward or raising straight legs, other provoking factors (coughing, sneezing), leading to an increase in intravertebral pressure and displacement of the roots, increase radicular pain in the lower back.

Among the projected pains, compression radiculopathy is of particular importance - pain syndrome in the lumbosacral region with irradiation to the leg (a consequence of compression of the nerve roots by a herniated disc or a narrow spinal canal). Such pain in the lower back, caused by compression of the lumbosacral roots, has a number of features. In addition to the pronounced emotional coloring characteristic of neuropathic pain (burning, piercing, shooting, crawling ants, etc.), it is always combined with neurological symptoms in areas predominantly innervated by the affected root: sensitivity disorders (hypalgesia), a decrease (loss) of the corresponding reflexes and the development of weakness in the "indicator" muscles, at the same time, if the compression of the root occurs at the level of the corresponding intervertebral foramen, the pain occurs not only when walking or moving, but also persists at rest, does not intensify with coughing or sneezing and is monotonous.

Sometimes, due to degenerative changes in the bone structures and soft tissues of the root canals, narrowing of the spinal canal (lateral stenosis) occurs. The most common causes of this process are hypertrophy of the yellow ligament, facet joints, posterior osteophytes and spondylolisthesis. Since the L5 root is most often affected, neurogenic (caudogenic) intermittent claudication with clinical manifestations in the form of pain in one or both legs during walking, localized above or below the knee joint or in the entire lower limb and, sometimes, a feeling of weakness or heaviness in the legs is considered characteristic of this pathology. Almost always, it is possible to detect a decrease in tendon reflexes and an increase in paresis. A decrease in the pain that has arisen when bending forward is characteristic, and limitation of extension in the lumbar spine with a normal range of flexion is diagnostically important.

How is low back pain diagnosed?

Sometimes compression radiculopathy must be differentiated from Bechterew's disease, which can also manifest as pain in the buttocks, spreading to the back of the thighs and limiting movement in the lower back. As noted above, lower back pain is divided into specific and non-specific.

Non-specific lower back pain is usually local in nature, i.e. it can be clearly defined by the patient himself. In terms of duration, it is usually (up to 90%) acute or subacute. The general well-being of patients may suffer only with pronounced pain intensity, mainly due to deterioration of the psycho-emotional state.

In the vast majority of cases, acute lower back pain is caused by musculoskeletal disorders and is a benign, self-limited condition that does not require special laboratory and instrumental diagnostic measures. As a rule, such patients have a good prognosis: full recovery within 6 weeks is noted in more than 90% of cases. However, it should be especially emphasized that the lower back pain syndrome, as shown above, is caused by many reasons - both serious, threatening the patient's health, and transient, functional, after the disappearance (elimination) of which the person again becomes practically healthy. Therefore, already at the first visit of the patient, it is necessary to identify signs that indicate the presence of both non-vertebrogenic (i.e. pathogenetically not associated with damage to the spinal column) and vertebrogenic "serious" pathology that has caused acute back pain. Vertebrogenic "serious" causes of back pain include malignant neoplasms (including metastases) of the spine, inflammatory (spondyloarthropathies, including AS) and infectious lesions (osteomyelitis, epidural abscess, tuberculosis), as well as compression fractures of the vertebral bodies due to osteoporosis. Non-vertebrogenic pain syndromes can be caused by diseases of the internal organs (gynecological, renal and other retroperitoneal pathology), herpes zoster, sarcoidosis, vasculitis, etc. Although the incidence of "serious" causes of acute back pain during the first visit to a doctor is less than 1%, all patients should undergo an examination aimed at identifying a possible serious, life-threatening pathology. Currently, this group of diseases includes:

• oncological diseases (including history);
• vertebral fractures;
• infections (including tuberculosis);
• abdominal aortic aneurysm;
• cauda equina syndrome.

In order to suspect these pathological conditions, during clinical examination it is necessary to pay attention to the presence of fever, local pain and increased local temperature in the paravertebral region, which are characteristic of an infectious lesion of the spine. Its risk is increased in patients receiving immunosuppressive therapy, intravenous infusions, suffering from HIV infection and drug addiction. The presence of a primary or metastatic tumor may be indicated by unexplained weight loss, a history of malignant neoplasm of any localization, persistent pain at rest and at night, as well as the patient's age over 50 years. Compression fracture of the spine most often occurs as a result of trauma, with the use of glucocorticosteroids and in patients over 50 years. In the presence of a pulsating formation in the abdomen, signs of atherosclerotic vascular lesions and unrelenting pain in the lower back at night and at rest, there is a high probability that the patient has developed an abdominal aortic aneurysm. If the patient complains of weakness in the leg muscles and has decreased sensitivity in the anogenital area (“saddle anesthesia”) and pelvic disorders, compression of the structures of the equine tail should be suspected.

The consequence of neoplasms is less than 1% (0.2-0.3%) of all acute pain sensations, while approximately 80% of patients with malignant tumors are people over 50 years old. The presence of a tumor in the anamnesis is a highly specific factor of neoplastic etiology of pain sensations, which must be excluded first of all. Other important signs that allow one to suspect the tumor nature of pain in the lower back:

• unexplained weight loss (more than 5 kg in 6 months):
• no improvement within a month of conservative treatment;
• duration of severe pain syndrome more than one month.

In patients under 50 years of age with no history of cancer and unexplained weight loss who have been helped by conservative therapy for 4-6 weeks, cancer as a cause of back pain can be excluded with almost 100% certainty.

Fever with acute pain sensations is detected with a frequency of less than 2%. The probability of an infectious nature of the pain syndrome increases if:

• recent history of intravenous manipulation (including drug addiction);
• have urinary tract, lung or skin infections.

The sensitivity of the fever syndrome for infections in the back ranges from 27% for tuberculous osteomyelitis to 83% for epidural abscess. Increased sensitivity and tension in the lumbar region during percussion have been shown to be 86% for bacterial infections, although the specificity of this test does not exceed 60%.

Cauda equina syndrome is a very rare pathological condition, the frequency of which is less than 4 per 10,000 patients with low back pain. The most common clinical syndromes are:

• urinary dysfunction; weakness in the leg muscles;
• decreased sensitivity in the anogenital area (“saddle anesthesia”).

If they are not present, the likelihood of this syndrome is reduced to less than 1 in 10,000 patients with low back pain.

A vertebral compression fracture may be suspected in a patient with pain who has had a recent significant spinal injury, or who has established osteoporosis, or who is over 70 years of age. It should be noted that most patients with an osteoporotic fracture do not have a history of back injury.

The most common form of vascular aneurysm is abdominal aortic aneurysm. Its incidence at autopsy is 1-3%, and it is found 5 times more often among men than among women. Pain syndrome can be a sign of aneurysm growth, warning of an imminent rupture of the aorta. Lower back pain with an aneurysm often occurs at rest, and the pain itself can spread to the anterior and lateral surfaces of the abdomen; in addition, a pulsating formation can be palpated there.

If muscle weakness in the limbs increases, the patient should immediately consult a neurosurgeon, as this symptom may indicate a severe disc herniation, in which case timely surgical treatment leads to a more favorable outcome.

Signs of serious pathology, called “red flags” in English-language literature and indicating a possible secondary nature of lower back pain, are listed below.

Anamnestic data:

• malignant tumors, unexplained weight loss:
• immunosuppression, including long-term use of glucocorticoids;
• intravenous drug addiction;
• urinary tract infections;
• pain that increases or does not subside with rest;
• fever or constitutional symptoms:
• coagulopathy-thrombocytopenia, use of anticoagulants (possibility of development of retroperitoneal, epidural hematoma, etc.);
• an elderly patient with new-onset lower back pain;
• metabolic bone disorders (eg, osteoporosis):
• significant trauma (a fall from a height or a severe bruise in a young patient, a fall from standing height or lifting something heavy in an elderly patient with probable osteoporosis).

Current status:

• age under 20 or over 50 years;
• the presence of pain in the lower back, which intensifies at night, when lying on the back, and does not subside in any position;
• suspicion of cauda equina syndrome or spinal cord compression (urination and defecation disorders, impaired sensitivity in the perineum and movement in the legs);
• other progressive neurological pathology.

Physical examination and laboratory findings:

• pulsating formation in the abdominal cavity;
• fever:
• neurological disorders that do not fit into the picture of normal radiculopathy and persist (increase) over the course of a month:
• tension, stiffness of the spine;
• elevated ESR, CRP levels, unexplained anemia.

A picture that does not fit into the idea of benign mechanical pain in the lower back.

Lack of any positive effect from the generally accepted conservative treatment of the patient within a month.

Taking into account the above, the algorithm for diagnostic search and management of a patient with pain can be presented as follows.

• Examination of the patient taking into account the clinical signs of the disease and with particular emphasis on the presence of “signs of danger”.
• In the absence of “signs of danger,” the patient is prescribed symptomatic pain relief therapy.
• Identification of “signs of threat” requires further laboratory and instrumental examination and consultations with specialists.
• If additional examination does not reveal signs of diseases that threaten the patient’s condition, non-specific pain-relieving therapy is prescribed.
• When a potentially dangerous condition is identified, specific therapeutic, neurological, rheumatological or surgical measures are prescribed.

It should be emphasized once again that, according to internationally accepted standards, if the patient does not show any “signs of danger,” then there is no need to conduct laboratory and instrumental examinations, including even an X-ray of the spine.

Indications for consultation with other specialists

If a patient who has pain in the lower back is found to have “signs of a threat,” he or she must undergo further examination depending on the nature of the suspected pathology and be observed by specialists.

How to treat lower back pain?

Treatment for low back pain can be divided into two categories.

• The first is used in the presence of a potentially dangerous pathology, and it should only be performed by specialists.
• The second, when there is non-specific pain in the lower back without “signs of danger,” can be carried out by therapists and general practitioners; it should be aimed at relieving the pain syndrome as quickly as possible.

NSAIDs are the main drugs prescribed to relieve low back pain. However, it should be emphasized that there is no evidence that any NSAID is clearly more effective than others, and there is insufficient evidence that they are effective in treating chronic low back pain.

Another aspect is the use of muscle relaxants. These drugs are classified as auxiliary analgesics (co-analgesics). Their use is justified in painful myofascial syndromes and spasticity of various origins, especially in acute pain. In addition, in myofascial syndromes, they allow you to reduce the dose of NSAIDs and achieve the desired therapeutic effect and in a shorter time. If the pain in the lower back has become chronic, the effectiveness of prescribing muscle relaxants has not been proven. This group of drugs primarily includes centrally acting drugs - tizanidine, tolperisone and baclofen.

It should also be noted that almost all types of physical intervention, including electrical therapy, are considered questionable and their clinical effectiveness in reducing pain intensity has not been proven. The only exception is therapeutic exercise, which really helps speed up recovery and prevent relapses in patients with chronic lower back pain.

Prescribing bed rest for acute lower back pain is harmful. It is necessary to convince the patient that maintaining daily physical activity is not dangerous, and advise him to return to work as soon as possible. The only exception is patients with compression radiculopathy, for whom it is necessary to achieve maximum unloading of the lumbosacral spine in the acute period, which is easier to achieve with bed rest (for 1-2 days) with the simultaneous prescription, in addition to analgesic therapy, of diuretics with vasoactive drugs to reduce swelling and improve microcirculation.

Further management

Uncomplicated lower back pain is usually a relatively benign pathological process that can be easily relieved with conventional pain medications and does not require additional laboratory or instrumental examination methods. These patients should be monitored by therapists or general practitioners.

ICD-10 code

Low back pain is a symptom, not a diagnosis, which was included in ICD-10 as registration category M54.5 "Low back pain" due to its high prevalence and the frequent inability to establish a specific nosological cause of pain.