Sciatica is the term used to describe pain brought on by sciatic nerve inflammation. Pain, ranging from mild to severe, can be brought on by anything that irritates this nerve. Typically, a compressed nerve in the lower spine is what causes sciatica. The term "sciatica" is frequently confused with other types of back pain or radicular leg pain. Sciatica, though, is not only a back issue. The longest and widest nerve in the human body is the sciatic nerve. The L4 through S2 nerve roots come together to produce the sciatic nerve at the pelvis. The sciatic nerve is without a doubt the biggest nerve in the body, measuring up to 2 cm in diameter. It originates in the lower back and extends through the buttocks, down the legs and finally to the knee. The skin of the foot and much of the lower leg receive sensation from this nerve, which also controls a number of lower leg muscles. Sciatica is a sign of another issue that affects the sciatic nerve rather than a true medical illness. According to some experts, up to 40% of people will at some point throughout their lives experience sciatica. Sciatica is a crippling condition where the patient feels pain and/or paresthesia in the sciatic nerve or a related lumbosacral nerve root's distribution. The pain caused directly by disease in the sciatic nerve or the sciatic nerve root is known as sciatica. Twisting, bending, coughing and lumbar spine flexion can all aggravate sciatica. The hamstrings and lower extremity adductors receive direct motor function from the sciatic nerve, while the calf muscles, anterior lower leg muscles and some intrinsic foot muscles receive indirect motor function. The sciatic nerve also indirectly supplies sensation to the plantar foot, as well as the posterior and lateral lower legs, through its terminal branches. It is crucial to understand that the majority of sciatica cases are caused by inflammatory conditions that irritate the sciatic nerve. Direct compression of the nerve, on the other hand, results in more severe motor dysfunction, which is frequently not detected and, if present, would call for a more thorough and quick workup [1-3]. Depending on the source, sciatic pain is described differently by various people. From "burning", "electric", or "stabbing" pain to "sharp, shooting, or jolts of pain." Pain may be ongoing or intermittent. When compared to the lower back, it usually affects the leg more severely and it may get worse if you stand for extended periods of time.

The literature on sciatica was gathered from a variety of textbooks, medical journals and published literary works. It was then analysed, thoroughly discussed and the conclusions were provided here.

Anatomical Features

Because there is a finite amount of room in the neural canal and intervertebral foramina, any disorder that diminishes or changes the amount of space there could harm the spinal cord or peripheral nerve roots, or could even cause ischemia by squeezing blood vessels.

Prolapsed Intervertebral Disc

Compression of the spinal cord and/or nerve roots results from this condition most frequently. The intervertebral discs, which each include a central nucleus pulposus made of soft gelatinous material and a central annulus fibrosus made of cartilage, separate the bodies of the vertebrae. When a disc prolapses, the nucleus pulposus herniates, allowing the posterior longitudinal ligament and annulus fibrosus to protrude into the neural canal. The damage solely affects the nerve roots since it most frequently occurs in the lumbar area, typically below the level of the spinal cord, or below L2. Compression of the chord is also possible if it happens in the cervical area. Herniation can happen quickly, usually in young adults following vigorous exercise or exertion, or it can happen gradually in elderly persons when bone disease or disc degeneration cause a rupture during little exercise. The hernia may occur in a variety of ways, including unilaterally, compressing the spinal cord, the anterior spinal artery and potentially both bilateral nerve roots. The results vary depending on the hernia's size and how long pressure is exerted for. Due to strain on the nerve ends in the posterior longitudinal ligament, small herniations induce localised pain [4]. Large herniations can result in unilateral or bilateral paralysis as well as acute or persistent pain that is thought to originate in the region that is supplied by the compressed sensory nerve, such as the leg or foot. Localized muscular spasm brought on by pressure on motor nerves due to compression of the anterior spinal artery, which results in ischemia and possibly necrosis of the spinal cord [4].

Causes

Spinal Disc Herniation: The major cause of sciatica, occurring in roughly 90% of patients, is a herniated spinal disc pressing on one of the lumbar or sacral nerve roots [5]. If the disc tear heals and the pulposus extrusion and inflammation stops, the sciatica brought on by pressure from a herniated disc and swelling of the surrounding tissue may go away on its own [5].

Spinal Stenosis

The spinal canal, through which the spinal cord flows, narrows and compresses the spinal cord, cauda equina, or sciatic nerve roots in the case of lumbar spinal stenosis, one of the other causes of compressive spinal conditions. The spinal cord's available space can constrict due to bone spurs, spondylolisthesis, inflammation, or a herniated disc, which can squeeze and irritate nerves from the spinal cord that travel to the sciatic nerves [6-8].

Piriformis Syndrome

According to various analyses, piriformis syndrome can be a "very rare" cause of low back or buttock discomfort or it can account for up to 8% of cases. The sciatic nerve travels through, or under, the piriformis muscle in 15% of the population as opposed to beneath it. The sciatic nerve is thought to be compressed when a muscle shortens or spasms as a result of injury or overuse [6]. Since a wallet kept in the back hip pocket compresses the buttock muscles and sciatic nerve when the bearer sits down, it has been known as "wallet sciatica." When the nerve root is healthy, the piriformis syndrome might produce sciatica [7,8].

Degenerative Disc Disease (DDD)

Each vertebral segment is "cushioned" by a disc in the spine. The disc is more prone to herniation (rupture), which can cause localised or radiate pain, when the disc degenerates (deteriorates). When nerves in the low back are inflamed, disc herniation (also known as a "ruptured disc") can cause sciatica [9].

Isthmic Spondylolisthesis

Greek words (spondylo = vertebra and olisthesis = translation). A minor fracture in a piece of bone that joins the two joints on the back side of the spinal segment causes one vertebral body to slip forward on the one below it, resulting in the spine ailment known as Isthmic spondylolisthesis [10].

Pregnancy

The weight of the foetus pressing against the sciatic nerve while sitting or during leg cramps can potentially cause sciatica during pregnancy. The numbing effect on the legs, which can lead to loss of balance and falling, might have an indirect negative impact on the mother or foetus even though most cases do not directly affect either. There is no established treatment for sciatica brought on by pregnancy [11].

Other Causes

Malignancy, infection, vascular compression, bony compression, muscular compression, epidural adhesions and gynaecological conditions are additional causes of sciatica (Table 1) [12].

Table 1: Other Causes of Sciatica

Epidemiology

Gender, body habit, parity, age, genetic variables, occupation and environmental factors have all been explored as potential environmental and inherent factors that may affect the development of sciatica. Although body mass may have been linked to low back pain, a cross-sectional research of 2946 women and 2727 men revealed neither gender nor body mass had an impact on the development of sciatica [13]. Body height could increase the risk of sciatica. This only seems to be important for males in the 50–64 age range [14]. Additionally, it has been determined that sciatica and parity up to six do not correlate [15]. Age has an impact on the prevalence of sciatica. The incidence rarely occurs before the age of 20, rises in the fifth decade and then diminishes [16]. The age distribution of patients seeking treatment for lumbar disc herniation was also noted [17]. Up until the age of 64, the Odds Ratio (OR) of experiencing sciatica increased by 1.4 for each additional 10 years of age. It's interesting to note that as people age, the disc herniation site seems to shift. Although L4/5 or L5/S1 levels account for the majority of disc herniations, L3/4 or even L2/3 levels tend to be more frequently affected as people get older [18].

Pathophysiology

The L4 through S2 nerve roots make up the sciatic nerve. The big sciatic nerve in the pelvic cavity is formed by the fusion of several nerve roots. The sciatic nerve then leaves the pelvis via the posterior sciatic foramen. The nerve travels inferiorly and anteriorly to the piriformis after leaving the pelvis and laterally to the gemellus superior, inferior, obturator internus and quadratus femoris. The sciatic nerve then passes through the biceps femoris and enters the posterior thigh. Last but not least, the sciatic nerve gives origin to the tibial and common fibular nerves at the knee's posterior popliteal fossa. When there is disease somewhere along the nerve's journey, sciatica symptoms develop [19]. According to the research, a complicated interaction of inflammatory, immune and pressure-related processes may be involved. Pathophysiology of the disc herniation is shown in Figure 1 [20].

Risk Factors

The key finding of earlier studies is that physically demanding employment increases the incidence of sciatica [21]. In the present study, sedentary work involving the handling of moderately heavy things, as well as physically light labour requiring standing or moving, predicted the occurrence of sciatica, whereas heavy/very heavy physical work even protected against being admitted to the hospital with sciatica. Physically less fit people might prefer lighter labour duties, which would account for the higher risk in these tasks. On the other hand, participants who are able to sustain physically demanding jobs are likely in better physical and muscular condition, which would improve their ability to control their spine and trunk neuromuscularly. The fact that people who continue to perform physically demanding occupational duties have better tissue tolerance may be one reason for the decreased probability of hospitalisation for sciatica. The "healthy worker effect" may potentially affect the findings in many occupational studies since sick people may be kept out of the workforce [22]. The intradiscal pressure appears to be higher when seated and this may be one of the underlying factors causing sciatica in jobs that require prolonged sitting [23]. We discovered that carrying and lifting large objects increased the likelihood that sciatica would cause hospitalisation. It has been discovered that carrying and lifting raise intradiscal pressure [24,25]. Sciatica incidence was predicted by baseline smoking behavior [26]. According to some theories, smoking may exacerbate sciatica by interfering with the nutrition of the intervertebral discs [27]. Increasing the intervertebral discs' capacity to produce pro-inflammatory cytokines [28]. Hospitalization for sciatica appears to be most common among overweight or obese people exposed to whole-body vibration, in people who lift or carry large goods, or in people who have sedentary jobs that require the handling of moderately heavy objects [28].

Diagnosis

Leg discomfort is experienced by about two thirds of people with Low Back Pain (LBP) [29,30]. Leg pain caused by nerve root involvement (sciatica) or non-specific referred pain from other structures in the low back are the two possibilities for a differential diagnosis when the possibility of serious spinal disease ('red flags') or other non-spinal causes for the pain has been ruled out It is acknowledged that making this diagnostic choice is challenging [31] and doctors may dispute on the diagnosis [32]. It is not always possible or necessary to make specific diagnoses in a primary care setting (disc herniation, spinal stenosis), but early recognition and differentiation of Low Back-Related Leg Pain (LBLP) symptoms (sciatica versus referred leg pain) are crucial for communicating the likely diagnosis and prognosis to patients, creating treatment plans and directing the need for prompt referrals to specialist services. There is no accepted medical terminology or definition for sciatica [33–35]. In this subgroup of LBP patients, this has resulted in variability, which limits the generalizability of study findings because the same disease entity may not be assessed across investigations. When compared to results from an MRI or surgery, the history [36] and physical examination [37–39] have generally performed poorly as diagnostic tools for diagnosing sciatica. To enhance diagnostic performance, combining clinical evaluation items is advised [37,40]. Clinicians evaluating patients with LBP in primary care and other settings combine a number of patient traits and symptoms to create a diagnosis [41]. 

Figure 1: An Overview of the Pathogenesis of Discogenic Sciatica

Diagnostic models are instruments that integrate predictors to calculate the likelihood that an individual with a specific predictor profile has the condition of interest [42]. The Lasègue's sign or straight leg rising test is the examination that is used the most [43].

Straight-Leg Test

The patient is placed in a relaxed, supine position while being subjected to the straight-leg test. After that, the examiner raises the leg from the back, flexing at the hip joint while maintaining complete knee extension or keeping the leg straight. A lumbar disc herniation is typically the cause of discomfort that is replicated between 30 and 70 degrees of hip flexion and felt mostly in the back. Leg discomfort and parenthesis are probably brought on by lateralizing compression of a peripheral nerve. While not always the case, musculoskeletal pain will typically be reproduced at flexion angles above and below 30 degrees [44,45].

Supportive physiotherapy with analgesia and relaxation, notably through exercises and stretching, is a form of conservative treatment. The treatment's goals are to reduce pain and promote neurological healing. The most effective drugs are NSAIDs since they precisely address physiopathological demands (which are essentially inflammation-related issues), yet pure analgesics continue to be a useful therapeutic option. Utilizing anaesthetics and corticoids to block the damaged root is one option to the conservative treatment. Both of them directly affect the hernia by reducing its volume and the root by lowering the inflammatory response.

General

Starting out by relaxing and staying away from sports, lifting and bending. Analgesics and NSAIDs lessen musculoskeletal pain while also acting as an anti-inflammatory on irritated nerves and joints. Epidural steroid injections can be used to treat neurogenic claudication, radiculopathy-related lower extremities pain and low back pain. To lessen segmental spinal instability and pain, a brace might be helpful [46].

Pain Medication

In general, acetaminophen, NSAIDs, oral steroids, narcotic medicines and muscle relaxants are utilised to treat low back pain.

Chiropractic Manipulation

By relieving pressure on delicate neurological tissue, expanding range of motion, restoring blood flow, reducing muscle tension and inducing a number of chemical reactions in the body (like endorphin release), manual manipulation by a chiropractor or other qualified health professional is thought to provide lower back pain relief.

Epidural Injections

Steroids are injected epidurally into the spine and by reducing inflammation in the troublesome location, they can relieve low back pain.

Transcutaneous Electrical Nerve Stimulators (TENS)

These gadgets give mild electrical stimulation that blocks the lower back's painful impulses.

Surgery

Nerve structures are decompressed surgically via laminectomy or microdiscectomy.

Physical Therapy, Exercises and Bracing

A thorough rehabilitation regimen involving manual treatment, hip and lumbar stretching and strengthening activities.

Treatment for Piriformis Syndrome

Local anaesthetics (such lidocaine), anti-inflammatory medications, corticosteroids, botulinum toxin, or a combination of the three are examples of therapeutic injections that have been shown to be useful at treating muscle-related pain. Hip muscles shouldn't be stretched until the immediate pain has subsided. Start with mild stretches at that point, such the cross-legged stretch with the knee pulled up. Before returning to jogging actively, the muscle should be more flexible. Surgery may be advised in rare instances of intractable chronic pain. Surgery to release the piriformis muscle is frequently successful.

Panchakarma Therapy

Since ancient times, several care techniques for Sciatica (Gridhrasi) have been mentioned in Ayurvedic literature. These have withstood the test of time and continue to be effective in providing comfort to those who are afflicted with this terrible illness. The first logical step in treatment is Nidana Parivarjan (avoid causative factors), which is followed by the various Panchakarma therapies, including Snehana (oleation therapy), Swedana (sweating therapy), Vamana (emesis therapy), Virechana (purgation therapy), Niruha and Anuvasana Basti (medicated enema), Siravedhana, Raktamokshana (bloodletting), Agnikarma (thermal cautery) and Shastrakarma (surgical intervention) [47].

Patient Counselling

• 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 aqua therapy

• Use of proper lifting techniques

Sciatica is a condition that develops when a nerve is squeezed as a result of a herniated disc, a bone spur, or any other underlying cause. Since it is the longest and widest nerve, the sciatic nerve has control over a significant portion of the lower limbs. Although ageing is the main cause of sciatica, smoking and work-related variables are also risk factors. MRI studies allow for a more accurate diagnosis when compared to the results of a physical examination. In addition to sensible medication therapy, physical therapy can aid in easing sciatica pain. It is important to stay as far away from activities that could cause sciatica as you can. Even in the present period, Panchakarma procedures appear to be helpful.

Acknowledgment

I acknowledge and thank to all my coauthors, study participants and I also would like to thank all the Staff of Sultan-ul-Uloom college of Pharmacy and Parul Institute of Pharmacy and Research, Parul University for providing resources to complete this research.

Authors Contributions

All authors have contributed to the preparation of manuscript.

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