Pain, be it lower back, upper back, or any other type, is classified as either acute or chronic. Chronic pain is often defined as pain lasting more than three months. The three-month mark dividing the two assumes that the original cause of the injury should be healed by then, but even healing can leave in its wake a chronic syndrome that is a different disease altogether. The three-month mark also denotes that if the original cause has not healed, then it unlikely to do so and will persist as an ongoing chronic pain.
What are the causes of low back pain?
Most adults have low back pain at some point in their lives. Most of these adults—up to 85% of them— will be unable to identify the cause. Most patients who have low back pain for an unidentifiable reason will improve over a few weeks. However, the longer it takes for pain resolution, the lower the likelihood of the back reverting to a pain-free state.
Common causes of low back pain include:
- Herniated disc, or the compression of the spinal cord (spinal stenosis) or the cauda equina (termination of the spinal cord);
- Ankylosing spondylitis;
- Vertebral osteomyelitis;
- Vertebral facture resulting in compression (compression fracture).
What are the risk factors for low back pain?
- Smoking: Smoking is a vasoconstrictor, which means lower blood flow and oxygen to the areas that are inflamed and to the muscles that are overreaching to splint a person’s posture against the pain. This leads to cramping.
- Obesity: This is purely physics. Many lower back pain episodes resolve when there is less weight on the cushioning and muscular structures supporting the skeleton.
- Age: This is simply years of wear-and-tear, age-dependent inflammation (osteoarthritis), and bone loss.
- Being female: This is probably related to the increased tendency toward osteoporosis seen in postmenopausal women.
- Physically taxing work: Such work brings about wear-and-tear and usually involves little or no down time for healing after an injury.
- Sedentary lifestyle and work: Unvaried posture positions as well as the obesity that comes with a sedentary lifestyle increase the risk of low back pain. Persistent non-ergonomic (slouching) positions also adds to this.
- Stressful work.
- Less educated: This makes manual labor or physically demanding work more likely.
- Anxiety and depression.
How is low back pain diagnosed?
- Examination of medical history and the carrying out of physical exam: This involves paying attention to pressing on the spine, carrying out a neurological exam, and inspecting the back and posture.
- Straight leg raising: This and other movements are useful to determine if there is a neuropathy (radiculitis).
- Imaging studies: These are of limited usefulness in that those with pain may show no findings, and incidental findings may be found in those without back pain. For these reasons, low back pain of less than four weeks does not require imaging.
- MRI without contrast (in most cases): If there is previous scarring from a back surgery, use contrast to separate scarring from disc protrusion.
How is low back pain treated?
Since most acute low back pain presentations will improve within a month, treatment is meant to address the symptoms. Treatments can include the following:
- No bedrest: With bedrest, recovery is slower, and patients have more pain. Normal activity should be encouraged as soon as is feasible. If pain hinders normal activity, activity should be reduced but slowly increased thereafter.
- Superficial heat: This provides short-lived moderate relief.
- Massage: This may be helpful.
- Acupuncture: This may be helpful.
- Spinal manipulation: This may give modest relief.
- Physical therapy: For acute pain, recommend PT only if a patient has risk factors for chronic low back pain, such as poor health and/or depression/anxiety.
- Medications: The following medications are presented in order of trial:
- Muscle relaxants, including the following:
- Opioids: Because the most common cause of chronic pain is inadequately treated acute pain, opioids are on the list but are far down the choice hierarchy because of the high likelihood that patients will abuse them.
- Tramadol: A non-opioid drug that acts on opioid receptors. There is a lower chance of abuse or constipation.
Treatments with little or no benefit includes cold applications, traction, lumbar supports, and acetaminophen. Although yoga may be helpful with chronic pain, it hasn’t been shown to ameliorate acute back pain.
Chronic low back pain
Since this is back pain that lasts more than three months, it can be a neurological disease remaining from the healed original injury or continued pain from a chronic, on-going process. The goal of pain management for chronic low back pain is the return of function and not necessarily complete pain relief. The following are tips and treatments for chronic low back pain:
- Avoid pharmacologic therapy initially, since any therapy for a chronic condition is likely a chronic therapy.
- Self-care: Maintain activity as tolerated.
- Active interventions: These include cognitive behavioral therapy (CBT); tai chi; yoga; and other MBSR (mindfulness-based stress reduction), including biofeedback.
- Physical therapy: This includes motor control exercises, core strengthening, flexion/extension movements, aerobic exercise, and mind-body exercise (yoga, Pilates).
- Pharmacologic therapy should be pursued of necessary or if previous interventions have failed. Turn to the following medications:
- NSAIDs with a nonbenzodiazepine muscle relaxant:
- Non-opioid tramadol: Tramadol attaches to the opioid receptors on nerves, so it acts as a weak narcotic. It also increases serotonin, a development that is thought to enhance pain relief, but it must be used with caution if a patient is on an SSRI or SNRI antidepressant.
- Lumbar support may or may not be helpful.
- Acupuncture, massage—may have short-term relief, but studies are inconclusive on any long-term relief.
Medications with little or no benefit based on studies so far include the following:
- Gabapentin and pregabalin (Neurontin and Lyrica, respectively);
- Herbal remedies.
Therapies that have limited or no benefit:
- Interferential therapy;
- Low-level laser;
- Ultrasound treatment;
- Shortwave diathermy;
- Traction treatment.
The differences between treatment of acute and chronic lower back pain begin to blur the more unsuccessful the treatments become. Some patients with acute lower back pain that is eventually resolved go on to have chronic pain, thereby impacting their personal productivity.