Invasive Treatment of Lower Back Pain

Lower back pain is one of the most common conditions that lead a person to a doctor. It is defined as pain limited upwards by the lower part of the rib arch and down by the lower gluteal crease. It can spread in the lower limb, but not necessarily. About 7.5% of the world's population suffers from back pain. Most people experience an episode of low back pain at least once in their lives. A survey carried out in 2019 on the incidence of chronic pain in Slovenia ranked lower back pain first, with 63% of respondents describing it.

The prevalence of low back pain is between 21% and 75%. In 60% of these individuals it can lead to a reduction in the quality of life due to functional disability. Since 1990, lower back pain has been the leading cause of disability. Causes may be fractures of the osteoporotic vertebrae, spondyloarthritis, malignancy, infections. In 2019, the group of patients aged 50 to 54 were the most affected. Episodes of acute low back pain are usually transient and short-lived, but pain can persists occasionally in more than half of these patients. In most patients with lumbar back pain, the condition improves significantly within six weeks, 33% patients recover within the first three months and in 65% pain remains present also after 12 months. In 33% of patients, the pain recurs within a year after recovery from the previous episode.

Acute and initial chronic (> 6 months) back pain often occurs in the working active population. In 10 percent of patients, acute back pain, lasting more than 6 months, progresses into chronic. After an initial episode, lower back pain often repeates within 12 months after recovery. Treatment should be bio psycho social from the start. The prevalence of back pain is higher in women compared to men (ratio 1.27). This difference is greater when women reach postmenopausal period. It is gender-related (e.g. hormones, differences in the endogenous opioid system). Socio-economic status (level of education) is associated with recurrence of pain and disability, especially in men. The reasons could be behavioural and environmental risks, the professional status, the accessibility to the health system. The socio-economic situation in childhood is a risk factor for the occurrence of back pain in adulthood.

Lower back pain, especially chronic, is a very complex condition that has different causes. There is no single pathophysiological mechanism that could explain the causes of low back pain. Therefore, despite its frequency, we often do not find an exact cause. In 85 - 95% it is defined as non-specific and results in only symptomatic treatment. The mechanisms ob pain overlap and combine with genetic, epigenetic, individual factors and lifestyle. On the other hand, when low back pain have a defined cause, the treatment can be causal. Specific causes of back pain may be fractures, infection, autoimmune diseases, nerve cramping.

Inflammation, hypersensitivity and altered spine innervation are present. Even if nerve tightness due to hernia disci is not present, changes in peripheral nervous system may occur, which may contribute to the development of back pain. The cause could be inflammation in musculoskeletal structures. Compression and degeneration of intervertebral discs are associated with an increase in inflammatory mediators, increased sensory innervation of the disc and plastic changes in peripheral and spinal sensory neuron. These changes indicate a biological mechanism of pain origin. These patients have altered and increased pain sensitivity. This may be due to peripheral or central sensitisation. Hyperalgesia fluctuates with pain intensity and normalises with pain reduction.

According to the latest classification, low back pain is nociceptive, neuropathic or neuroplastic.

In the first case, the pain is caused by irritation of pain-sensing receptors, and in the second by disease or damage of the somatosensory nervous system. In neuroplastic pain perception to stimuli is changed, the patient describes pain, although no clear cause of it is found. When the neuropathic component is also present, pain is more resistant to treatment, the quality of life is even lower and the cost of treatment is higher.

Treatment should be causal when the cause of pain is known. If the neuropathic component is also present then treatment should follow guidelines for neuropathic pain management.

At the beginning of the treatment of patients with non-specific low back pain, identification of those that would probably need more complex treatment was tried. In simple cases education and low doses of simple analgesics are needed. More complex patients are also referred to physiotherapy, and those who are more likely to develop chronic back pain, should be also referred to a psychologist.

An important place to terminate the back pain cycle has spine blockades, either local, trigger points blockades, or x-ray-guided blockades of facet joints or nerve roots.

The research will be conducted in the Department for Chronic Pain, Clinical Department of Anaesthesiology and Intensive Therapy. Patients with chronic low back pain and/or spinal nerve root impairment, scheduled for invasive treatment, will be included in the study. Trigger points blockade were compared to x-ray-guided blockade of small joints of the spine or nerve roots.

Experts from different medical fields are involved in the treatment of chronic low back pain, as the outcome of treatment depends very much on a multidisciplinary approach. Beside the biological component, pain is also affected by the psychological and social components.

In the present research determination after 1, 3 and 6 months after procedure the difference between the groups in pain intensity and in pain quality was tried. The impact of other factors on chronic pain treatment was also determined.

PROTOCOL

In the control group, local anaesthetic and long-acting corticosteroid will be used for trigger blockade. In the study group, a blockade of the small joints of the spine and/or roots of the spinal nerves under x-ray control will also be performed by a combination of local anaesthetic and a long-acting corticosteroid. In each group, 30 patients, will be randomised. The pain will be recorded by using a short pain questionnaire and a McGill pain questionnaire. The consumption of analgesics, VAS score and improvement of quality of life will be monitored.

DATA GHADERING

Following values will be monitored:

• scoring of a Short pain questionnaire and the McGill Pain Questionnaire T
• Analgesic consumption