Chronic Back Pain is pain, muscle tension, or stiffness localized below the costal margin and above the inferior gluteal folds, with or without leg pain (sciatica), and is defined as chronic when it persists for 12 weeks or more. Non-specific low back pain is pain not attributed to a recognizable pathology (such as infection, tumor, osteoporosis, rheumatoid arthritis, fracture, or inflammation). People in this review have chronic low back pain (>12 weeks’ duration).
Chronic low back pain (CLBP) is the most common musculoskeletal condition affecting the adult population, with a prevalence of up to 84% [rx]. Chronic LBP (CLBP) is a chronic pain syndrome in the lower back region, lasting for at least 12 weeks [rx]. Many authors suggest defining chronic pain as pain that lasts beyond the expected period of healing, avoiding this close time criterion. This definition is very important, as it underlines the concept that CLBP has well-defined underlying pathological causes and that it is a disease, not a symptom. CLBP represents the leading cause of disability worldwide and is a major welfare and economic problem [rx].
Types of Pain
There are multiple categories and types of pain, including neuropathic, nociceptive, musculoskeletal, inflammatory, psychogenic, and mechanical.
Peripheral neuropathic pain as the case post-herpetic neuralgia or diabetic neuropathy
Central neuropathic pain – cerebral vascular accident sequella
Pain due to actual tissue injuries such as burns, bruises, or sprains
Autoimmune disorders (rheumatoid arthritis)
Pain caused by psychologic factors such as headaches or abdominal pain caused by emotional, psychological, or behavioral factors
Causes ofChronic Back Pain
The more specific diagnoses are made based on the etiology of mechanical back strain, which is typically due to pathology involving the anatomy of the spine. While the lower back is usually affected the most, mechanical back pathology may involve any part of the bones, spinal ligaments, intervertebral discs, facet joints, spinal cord, spinal nerves, or paraspinal muscles. Common examples of pathology involving these structures include the following diseases[rx]:
Rheumatologic – ankylosing spondylitis, Reiter syndrome, psoriatic spondylitis, polymyalgia rheumatica
Oncologic – metastatic disease, spinal cord tumor, lymphomas, leukemia, multiple myeloma
Infectious – spinal epidural abscess, osteomyelitis, discitis
Gastrointestinal – pancreatitis, cholecystitis, bowel perforation
Vascular – aortic aneurysm, spinal epidural hematoma, aortoiliac disease
Renal – pyelonephritis, nephrolithiasis, perinephric abscess
Genitourinary – endometriosis, prostatitis, pelvic inflammatory disease
Spinal foraminal stenosis
Degenerative disc disease
Sacroiliac joint dysfunction
Facet joint syndrome
Ligamentous and muscular injury
Myofascial pain syndrome
Spine Related Causes
Sprains and strains
Disc prolapse and radiculopathy
Spinal stenosis and pseudo claudication
Cauda equina syndrome
Aortic disease dissection, aneurysm,
Genitourinary disease – Colic, tumor, and infection.
Gastrointestinal causes – pancreatitis and pancreatic cancer, peptic ulcer, cholecystitis, and cholangitis
Symptoms of Chronic Back Pain
Chronic low back pain symptoms are
- Pain in the back, and sometimes all the way down to the buttocks and legs. Some back issues can cause pain in other parts of the body, depending on the nerves affected.
- In most cases, signs, and symptoms clear up on their own within a short period. If any of the following signs or symptoms accompany back pain, people should see their doctor:
- Pain. It may be continuous, or only occur when you are in a certain position. The pain may be aggravated by coughing or sneezing, bending or twisting.
- Patients who have been taking steroids for a few months
- Drug abusers
- Patients with cancer
- Patients who have had cancer
- Patients with depressed immune systems
Fever/unexplained weight loss
Bowel or bladder dysfunction
Malignancy (document/record any previous surgeries, chemo/radiation, recent scans and bloodwork, and history of metastatic disease)
Can be seen in association with pain at night, pain at rest, unexplained weight loss, or night sweats
Significant medical comorbidities
Neurologic deficit or serial exam deterioration
Red flag conditions indicating possible underlying spinal pathology or nerve root problems
- Onset age < 20 or > 55 years
- Non-mechanical pain (unrelated to time or activity)
- Thoracic pain
- Previous history of carcinoma, steroids, HIV
- Feeling unwell
- Weight loss
- Widespread neurological symptoms
- Structural spinal deformity
Indicators for nerve root problems
- Unilateral leg pain > low back pain
- Radiates to foot or toes
- Numbness and paraesthesia in the same distribution
- Straight leg raising test induces more leg pain
- Localized neurology (limited to one nerve root)
Diagnosis of Chronic Back Pain
The physical examination should include assessment of symmetry in both the sagittal and coronal plane, gait, muscle atrophy, flexibility (flexion, extension, lateral flexion and rotation), touch and pinprick sensation in all relevant dermatomes, muscle power, deep tendon reflexes, Babinski, clonus, tenderness, straight leg raising, femoral stretch test and FABER’s test [rx].
The majority of low back pain do not have an identifiable diagnosis. Also, the standard battery of tests during the physical examination may not identify the strength and endurance of the paraspinal muscles, which plays a significant role in low back pain. The following tests could identify the weakness in these muscles
- A straight leg raising – can be painful in lumbosacral radiculopathy. The mechanism of pain during a straight leg raise is increased dural tension placed upon the lumbosacral spine during the test. Patients are supine during the test. The physician will flex the patient’s quadriceps with the leg in extension as well as dorsiflex the patient’s foot on the symptomatic side. Pain or reproduction of paresthesias is considered a positive test (Lasegue sign). Separately, a Bowstring sign is a relief of this underlying radicular pain with flexion of the patient’s knee on the affected side. The straight leg raising test is most helpful in the diagnosis of L4 and S1 radiculopathies.[rx][rx]
- An internal hamstring reflex – for L5 radiculopathy has also been shown to be a useful test. Tapping either the semimembranosus or the semitendinosus tendons proximal to the popliteal fossa elicits the reflex. When there is an asymmetry of the reflex between legs, this can be significant for radiculopathy.[rx]
- A contralateral straight leg raising test – is the passive flexion of the quadriceps with the leg in extension and foot in dorsiflexion of the unaffected leg by the physician. This test is positive when the unaffected leg reproduces radicular symptoms in the patient’s affected limb. However, the straight leg raising test is more sensitive but less specific than the contralateral straight leg raising test.[rx][rx][rx]
- The prone instability test – The patient starts by standing on one end of the examination couch. While continuing to stand on the foot end of the couch, the patient lowers his / her torso onto the couch. The patient can hold onto the couch’s sides for support. The examiner then palpates the lower lumbar spine to elicit tenderness. The patient then holds onto the couch and lifts his / her feet off the ground tensing the paraspinal muscles. Less pain and tenderness on repeat palpation of the lower lumbar spine, while the feet are off the floor, is considered positive. [rx]
- Prone Plank/Bridge – The patient is prone and elevates his / her entire body off the couch/mat on the forearms and tips of toes. The body should be parallel to the couch/mat. With adequate muscle strength, men should maintain this position for 124 +/- 72s and Women for 83 +/- 63s.[rx]
- Supine Bridge – The patient is supine and flexes the hip and knee to keep the feet flat on the couch/mat. The arms are flexed to position the hands beside the ears. The lower part of the torso and pelvis is lifted off the couch/mat, to maintain the trunk and the thigh in a straight line. With adequate muscle strength, men should maintain this position for 188 +/- 45s and Women for 152 +/- the 30s. [rx]
- X-rays – These are very accessible at most clinics and outpatient offices. This imaging technique can be used to assess for any structural instability. If x-rays show an acute fracture, it needs to be further investigated using a computed tomogram (CT) scan or magnetic resonance imaging (MRI).
- CT Scan – It is the preferred study to visualize bony structures in the spine. It can also show calcified herniated discs. It is less accessible in office settings compared to x-rays. But it is more convenient than MRI. In the patients that have non-MRI comparable implanted devices, CT myelography can be performed to visualize herniated disc.
- CT myelography – is when the patient has either a contraindication to having an MRI such as having a pacemaker device or defibrillator or be used when a standard CT or MRI is negative or equivocal. Myelography is a CT scan or an MRI with intrathecal administration of contrast. CT myelography visualizes a patient’s spinal nerve roots in their passage through the neuroforamina. CT myelography can be used to assess the underlying root sleeve. A unique population to recommend a CT myelogram is for patients with surgical spinal hardware. A CT is a poor test for the visualization of nerve roots, making it challenging to diagnose radicular disease.[rx][rx]
- Electromyography (EMG) – are complete after three weeks of symptoms, not before. Diagnostic tests such as EMG or nerve conduction studies are accurate only after three weeks of persistent symptoms. The primary reason why ordering an EMG or nerve conduction study is delayed three weeks following the development of pain is because fibrillation potentials after an acute injury lead to an axonal motor loss. These do not develop until two to three weeks following injury.[rx][rx]
- Cerebrospinal fluid analysis – is a useful test if there is a suspected neoplasm or infectious cause or radiculopathy symptoms. The recommendation for a lumbar puncture is in the case of a patient with negative or nondiagnostic neuroimaging, without known primary cancer, who has progressive neurological symptoms and has failed to improve promptly.
- MRI – It is the preferred and most sensitive study to visualize herniated disc. MRI findings will help surgeons and other providers plan procedural care if it is indicated.
- Bone scintigraphy – with single-photon emission computed tomography (SPECT) is more sensitive in detecting facet joint lesions and allows more accurate anatomical localization. A recent study suggested that SPECT could help to identify patients with low back pain who would benefit from facet joint injections [rx]. Facet joint block (FJB) is an indispensable diagnostic instrument in order to distinguish painful from painless facet joints, and to plan the intervention strategy.
- Foraminal nerve root entrapment test – is best visualized on T1-weighted MRI where the high contrast between fat tissue and the nerve root sheath is of great help. Usually, a combination of hypertrophic degenerative facets with osteophytes spurs posteriorly, and vertebral osteophytes and/or disc herniation anteriorly diminishes the anteroposterior diameter of the foramen. Foraminal height is lessened by degenerative disc disease and subsequent disc height loss. Whenever the normal rounded (oval) appearance of the nerve root sheath is lost in combination with loss of the surrounding fat tissue, nerve root compression should be considered.
Treatment of Chronic Back Pain
Use of hot or cold packs for comfort and to decreased inflammation
Avoidance of inciting activities or prolonged sitting/standing
Practicing good, erect posture
Engaging in exercises to increase core strength
Gentle stretching of the lumbar spine and hamstrings
Regular light exercises such as walking, swimming, or aromatherapy
Use of proper lifting techniques
For chronic low back pain, non-pharmacologic approaches were recommended as the first-line agents, including exercise, tai-chi, yoga, multidisciplinary rehabilitation, spinal manipulation, acupuncture, psychotherapy, low-level laser therapy, and electromyogram biofeedback.[rx]
Broadly speaking the treatments that have been used for non-specific low back pain are:
Basic Information – Including advice from practitioners regarding exercise and/or causes of back pain, formal education sessions, and written educational material.
- Physiotherapy – Physiotherapy aims to improve human function and movement and maximizing potential: it uses physical approaches to promote, maintain and restore physical, psychological, and social well-being, through the use of manual therapy, electrotherapy, and exercise.
- Manual therapies – including manipulation, massage, mobilization.
Other non-pharmacological interventions – Including, laser, transcutaneous electrical nerve stimulation, traction, ultrasound, IRR, wax therapy.
Back school – These include the components seen in some types of back school and multidisciplinary rehabilitation programs
Percutaneous electrical nerve stimulation (PENS)- including acupuncture, electro-acupuncture, nerve blocks, neuro reflexotherapy, percutaneous electrical nerve stimulation (PENS), injection of a therapeutic substance into the spine.
- Hydrotherapy – An exercise treatment conducted within a specially designed pool so that water supports the patient’s body weight
- Interferential therapy – An electrical treatment that uses two medium frequency currents, simultaneously, so that their paths cross. Where they cross a beat frequency is generated which mimics a low-frequency stimulation
- Intra-Discal Electrothermal Therapy (IDET) – Use of a heating wire passed through a hollow needle into the lumbar disc intended to seal any ruptures in the disc.
- Lumbar supports – External devices designed to reduce spinal mobility, e.g. corsets
- Manipulation – Small amplitude high-velocity movement at the limit of joint range taking the joint beyond the available range of movement.
- Transcutaneous electrical nerve stimulation (TENS) – Electrodes are placed on the skin and different electrical pulse rates and intensities are used to stimulate the area. Low-frequency TENS (also referred to as acupuncture-like TENS) usually consists of pulses delivered at 1 to 4 Hz at high intensity, so they evoke visible muscle fiber contractions. High-frequency TENS (conventional TENS) usually consists of pulses delivered at 50 to 120 Hz at a low intensity, so there are no muscle contractions.
- McKenzie – A system of assessment and management for all musculoskeletal problems that uses classification into non-specific mechanical syndromes. Assessment involves the monitoring of symptomatic and mechanical responses during the use of repeated movements and sustained postures
- Neuroreflexotherapy – Temporary implantations of epidermal devices into trigger points at the site of each subject’s clinically involved dermatomes on the back and into referred tender points in the ear.
- Traction – Traction performed by utilizing the patient’s own body weight (for example by suspension via the lower limb) or through movement.
- Intra-Discal Electrothermal Therapy (IDET) – Use of a heating wire passed through a hollow needle into the lumbar disc intended to seal any ruptures in the disc.
- Prolotherapy – Injections of irritant solutions to strengthen lumbosacral ligaments.
- The Back Book – A widely used advice booklet for people with back pain.
- Psychological treatment – Psychological treatments include a range of talking therapies including both psychotherapy and counseling there a several different broad psychological approaches, including, for example, cognitive-behavioral therapy (CBT). The focus of these treatments is usually on health promotion rather than treating specific disorders
- Counseling – Counselling takes place when a counselor sees a client in a private and confidential setting to explore a difficulty the client is having, distress they may be experiencing or perhaps their dissatisfaction with life, or loss of a sense of direction and purpose. It is always at the request of the client as no one can properly be ’sent’ for counseling.
- Analgesics – with or without paracetamol may improve pain and function compared with placebo. However, long-term use of NSAIDs or opioids may be associated with well-recognized adverse effects.
- Non-steroidal anti-inflammatory drugs – (NSAIDs) may be more effective than placebo at improving pain intensity in people with chronic low back pain. Nonsteroidal anti-inflammatory drugs were again the first-line pharmacologic agents recommended followed by tramadol and duloxetine as the second-line treatments.
- Antidepressants – decrease chronic low back pain or improve function compared with placebo in people with or without depression. Antidepressants such as tricyclic antidepressants and SNRI’s, topical analgesics, muscle relaxers, N-methyl-d-aspartate (NMDA) receptor antagonists, and alpha 2 adrenergic agonists are also the most effective pharmacological therapies.
- Muscle Relaxant – Benzodiazepines may improve pain, but studies of non-benzodiazepine muscle relaxants have given conflicting results.
- Gabapentin –The initial treatment of neuropathic pain and chronic back pain is often with gabapentin or pregabalin. It is Considere’s most effective treatments are in general recommended in chronic low back pain. They are indicated for postherpetic neuralgia, diabetic neuropathy, and mixed neuropathy.[rx]
- Tricyclic antidepressant (TCA) – A type of drug that can be used to treat back pain –this use is different from its action in treating depression, which usually requires a much higher dose. Examples include amitriptyline and imipramine
- Epidural corticosteroid injections – or local injections with corticosteroids and local anesthetic improve chronic low back pain treatment in people without sciatica. Facet-joint corticosteroid injections may be more effective than placebo at reducing pain.
- Epidural glucocorticoid injections – are beneficial for up to three months in duration in patients with acute lumbar radiculopathy. This benefit is modest yet clinically significant in the short-term.[rx][rx][rx] If a patient has not improved after six weeks of conservative management, they would be eligible for an epidural glucocorticoid injection.
- Oral systemic steroids tablet – are often prescribed for acute low back pain, and chronic low back pain although there is limited evidence to support their use. It is basically used to remove nerve-related inflammation, edema, hematoma.
- The serotonin-norepinephrine reuptake inhibitor (SNRI) – duloxetine is useful in treating chronic pain, osteoarthritis, and the treatment of fibromyalgia.[rx] Furthermore, the efficacy of duloxetine in the treatment of comorbid depression is comparable to other antidepressants.[rx][rx] Venlafaxine is an effective treatment for neuropathic pain, as well.[rx] A TCA can also be utilized, such as nortriptyline. TCA medications may require six to eight weeks to achieve their desired effect.[rx]
- Topical lidocaine and ointment – is a useful treatment for neuropathic pain and allodynia as in postherpetic neuralgia.[rx][rx] [rx][rx] Separately, topical capsaicin cream is an option for chronic neuropathic or musculoskeletal pain unresponsive to other treatments.[rx]
- Opioids – are considered a second-line option; however, they may be warranted for pain management for patients with severe persistent pain or neuropathic pain secondary to malignancy.[rx] [rx] Opioid therapy should only start with extreme caution for patients with chronic back pain and musculoskeletal pain.[rx] Side effects of opioids are significant and frequent and may include opioid-induced hyperalgesia, constipation, dependence, and sedation.[rx][rx]
- Buprenorphine – Patients with chronic pain who meet the criteria for the diagnosis of opioid use disorder should receive the option of buprenorphine to treat their chronic pain. Buprenorphine is a considerably better alternative for patients with very high daily morphine equivalents who have failed to achieve adequate analgesia. It is a considerably better alternative for patients with very high daily morphine equivalents who have failed to achieve adequate analgesia.
- Botulinum toxin – has also demonstrated effectiveness in the treatment of postherpetic neuralgia.[rx] The use of cannabis is also an area of interest in pain research. There is some evidence that medical marijuana can be an effective treatment of neuropathic pain and chronic low back pain, while the evidence is currently limited in treating other types of chronic pain.[rx]
As always, surgical treatment is the last resort.
- Surgical procedures for a herniated disc include laminectomies with discectomies depending on the cervical or lumbar area.
- Also, a patient with chronic low back pain can be managed via an anterior approach that requires anterior lumbar decompression and fusion. This patient can also be controlled with artificial disk replacement.
- Other alternative surgical procedures to the lumbar spine include a lateral or anterior approach that requires complete discectomy and fusion. The benefits of surgical intervention are moderate and tend to decrease over time following surgery [rx].
Types of exercise that have proven effective include the following:
Special programs – consisting of exercises to strengthen and stabilize the deep abdominal (tummy), back and pelvic muscles, as well as endurance training and exercises to stretch the muscles in the calves, hips and thighs.
Pilates – A total body workout in which strengthening the deep core muscles is key.
Tai chi – Originally an Asian martial art, tai chi is now practiced with slow, flowing movements. It can improve your balance and coordination skills, strengthen your muscles, and is said to help you relax your body and mind.
Yoga – An ancient Indian practice that aims to improve your body awareness and health. Yoga typically involves getting into various positions or carrying out certain sequences of movements that aim to promote strength and flexibility, body awareness, and a good posture.
Going on walks – Initial research suggests that going on a walk or brisk walking (Nordic walking) can help relieve back pain if done regularly – for instance, every two days for 30 to 60 minutes.
- Alexander Technique – The Alexander Technique is a taught self-care discipline that enables an individual to recognize, understand, and avoid habits adversely affecting muscle tone, coordination, and spinal functioning. Priority is given to habits that affect freedom of poise of the head and neck and that lead to stiffening and shortening of the spine, often causing or aggravating the pain.
- Chiropractic treatment – The diagnosis, treatment, and prevention of mechanical disorders of the musculoskeletal system, and the effects of these disorders on the functions of the nervous system and general health. There is an emphasis on manual treatments including spinal adjustment and other joint and soft-tissue manipulation. (World Federation of Chiropractic 2001)
A doctor or physiotherapist can help you to find a suitable type of exercise that is tailored to your situation and that you enjoy. People who have medical problems often find it helpful to have a course instructor or trainer with the appropriate experience.
Passive treatments, on the other hand, are carried out by other people – because you can’t do them yourself or because they don’t involve being active yourself. These treatments include the following:
Magnetic field therapy
Manual therapy techniques such as manipulation and mobilization of the spine
Applying heat or cold
The national guidelines consist of a collection of recommendations to improve the care of people with back pain. They were developed by several medical societies in Germany, based on current research.
- Acupuncture is a traditional Chinese treatment in which thin needles are inserted into specific points on the skin. According to traditional beliefs, the needles influence the flow of energy through the body when they are placed at points along the energy pathways (meridians). This is thought to activate the body’s own healing powers. But these energy pathways haven’t been proven to exist. Research has shown that it doesn’t matter where exactly you insert the needles and whether they actually enter the skin or not.
- There aren’t many good-quality studies on acupuncture for the treatment of chronic back pain. The best study concluded that acupuncture wasn’t more effective than “fake” acupuncture. Other studies found that acupuncture was slightly better at relieving the pain. But the effect was only small and didn’t last long.
- Inserting the acupuncture needles sometimes causes minor bleeding or bruising. To avoid infection, it is important to use sterile disposable needles. The risk of serious side effects is low.
- Transcutaneous electrical nerve stimulation (TENS) and percutaneous electrical nerve stimulation (PENS) are types of electrotherapy. These treatments use specialist equipment to trigger electrical impulses in the nervous system. This is done to stop pain signals being sent to the brain and to stimulate the production of endorphins, the body’s own pain-relieving hormones. TENS involves placing electrodes on the skin to send electrical impulses through the skin (transcutaneously). In PENS, the electrical impulses are transmitted through acupuncture needles inserted into the skin (percutaneously). Inferential current therapy is another technique that works in a similar way to TENS.
- Electrotherapy hasn’t been proven to relieve chronic back pain. In PENS, the small punctures in the skin may lead to minor bleeding or an infection.
Mobilization and manipulation of the spine
- Mobilization and manipulation are both types of manual therapy (“manual” comes from the Latin word for “hand”: manus). In mobilization, the therapist slowly moves the joint within its natural range of movement. Manipulation therapy, on the other hand, involves using short, sharp movements to push a joint beyond its normal range of movement.
- This type of sudden manipulation is also known as a chiropractic adjustment. Popping or cracking sounds may be heard during the procedure. These sounds occur when small bubbles of gas in the joints burst, just like when people crack their knuckles. It’s not exactly clear how these approaches are meant to work. Some of the current theories involve the release of muscle tension, the “unsticking” of tissue that is stuck together, and the realignment of certain joint structures.
- There are only a few good-quality studies on the manipulation and mobilization of the spine for the treatment of chronic back pain. Further research is needed in order to properly assess the effectiveness of these treatments.
- Manual therapy can sometimes have side effects such as sore muscles, cramping, and temporary stiff joints or pain. More serious complications of joint manipulation, such as broken bones or partial paralysis, are very rare. They could occur if, for instance, someone has osteoporosis or if the manipulation leads to a slipped disk or makes an existing slipped disk worse.
- Massages are a traditional way of treating back pain. They are meant to relax your muscles, reduce painful muscle tension, and increase your general sense of wellbeing.
- There are different types of massage. Common techniques include traditional (Swedish) massage, Thai massage, and acupressure. The methods differ in terms of the type of hand movements that are used and which parts of the body are massaged. They also vary in the amount of pressure applied, and whether the massage therapist uses their hands, fingertips, or special tools.
- Massages can relieve chronic back pain a little, for a short time, but they don’t have a lasting effect. Depending on how much pressure is applied to the affected area, the massage might be painful or you might feel sore afterward. Some people are allergic to massage oil, which can cause things like rashes.
- Osteopathy is a type of alternative treatment. It is based on the idea that all of the body’s structures and functions influence each other. This means that problems and diseases in one joint or organ are thought to have an effect on other parts of the body. Connective tissue is considered to be particularly important in osteopathy because it connects the body’s different physical structures and organs. There is no scientific proof that this theory is true, though.
- In osteopathy, therapists use nothing but their hands when performing physical examinations and treatments. The therapist first feels for areas of limited mobility and areas of tension in the body, as well as other kinds of tissue changes. Then they apply various stretching techniques, massage approaches, and hand movements to help with these problems. One type of osteopathic treatment is known as “muscle energy techniques.” The aim of these approaches is to release areas of physical tension by tensing the muscles and stretching. Research on osteopathic treatments for back pain has produced contradictory results. There is no proof that muscle energy techniques work.
In Germany, the job title “osteopath” isn’t protected and doesn’t require specific training.
- Other treatments that haven’t been proven to help reduce back pain include kinesiology taping, short-wave diathermy, laser therapy, magnetic field therapy, and therapeutic ultrasound.
Anatomy of The Low Back
The lumbar spine consists of five vertebrae (L1–L5). The complex anatomy of the lumbar spine is a combination of these strong vertebrae, linked by joint capsules, ligaments, tendons, and muscles, with extensive innervation. The spine is designed to be strong since it has to protect the spinal cord and spinal nerve roots. At the same time, it is highly flexible, providing for mobility in many different planes.
The mobility of the vertebral column is provided by the symphyseal joints between the vertebral bodies, with an IVD in between. The facet joints are located between and behind adjacent vertebrae, contributing to spine stability. They are found at every spinal level and provide about 20% of the torsional (twisting) stability in the neck and low back segments [rx]. Ligaments aid in joint stability during rest and movement, preventing injury from hyperextension and hyperflexion. The three main ligaments are the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), and ligament flavum (LF). The canal is bordered by vertebral bodies and discs anteriorly and by laminae and LF posteriorly. Both the ALL and PLL run the entire length of the spine, anteriorly and posteriorly, respectively. Laterally, spinal nerves, and vessels come out from the intervertebral foramen. Beneath each lumbar vertebra, there is the corresponding foramen, from which spinal nerve roots exit. For example, the L1 neural foramina are located just below the L1 vertebra, from where the L1 nerve root exits.
IVDs are located between vertebrae. They are compressible structures able to distribute compressive loads through osmotic pressurization. In the IVD, the annulus fibrosus (AF), a concentric ring structure of organized lamellar collagen, surrounds the proteoglycan-rich inner nucleus pulposus (NP). Discs are avascular in adulthood, except for the periphery. At birth, the human disc has some vascular supply but these vessels soon recede, leaving the disc with little direct blood supply in the healthy adult [rx]. Hence, the metabolic support of much of the IVD is dependent on the cartilaginous endplates adjacent to the vertebral body. A meningeal branch of the spinal nerve, better known as the recurrent sinuvertebral nerve, innervates the area around the disc space [rx].
The lumbar spine is governed by four functional groups of muscles, split into extensors, flexors, lateral flexors, and rotators. The lumbar vertebrae are vascularized by lumbar arteries that originate in the aorta. Spinal branches of the lumbar arteries enter the intervertebral foramen at each level, dividing themselves into smaller anterior and posterior branches [rx]. The venous drainage parallels the arterial supply [rx].
Typically, the end of the spinal cord forms the conus medullaris within the lumbar spinal canal at the lower margin of the L2 vertebra [rx]. All lumbar spinal nerve roots stem from the connection between the dorsal or posterior (somatic sensory) root from the posterolateral aspect of the spinal cord and the ventral or anterior (somatic motor) root from the anterolateral aspect of the cord [rx]. The roots then flow down through the spinal canal, developing into the cauda equina, before exiting as a single pair of spinal nerves at their respective intervertebral foramina. Cell bodies of the motor nerve fibers can be found in the ventral or anterior horns of the spinal cord, whereas those of the sensory nerve fibers are in the dorsal root ganglion (DRG) at each level. One or more recurrent meningeal branches, known as the sinuvertebral nerves, run out from the lumbar spinal nerves. The sinuvertebral nerve, or Luschka’s nerve, is a recurrent branch created from the merging of the grey ramus communicans (GRC) with a small branch coming from the proximal end of the anterior primary ramus of the spinal nerve. This polisegmentary mixed nerve directly re-enters the spinal canal and gives off ascending and descending anastomosing branches comprising both somatic and autonomic fibers for the posterolateral annulus, the posterior vertebral body, and the periosteum, and the ventral meninges [rx], [rx]. The sinuvertebral nerves connect with branches from radicular levels both above and below the point of entry, in addition to the contralateral side, meaning that localizing pain from the involvement of these nerves is challenging [rx]. Also, the facet joints receive two-level innervation comprising somatic and autonomic components. The former conveys a well-defined local pain, while the autonomic afferents transmit referred pain.
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