Sciatica is a debilitating condition in which patients experience pain or paresthesia along the path of the sciatic nerve in a dermatomal pattern. Up to 2 cm in diameter, the sciatic nerve is the largest in the body and – directly or indirectly – innervates the hamstrings, lower extremity adductors, calf muscles, anterior lower leg muscles, and intrinsic foot muscles.1-3 In the general population, the annual prevalence of disc related sciatica is 2.2%.1 In patients with low back pain, the annual prevalence is 5-10%.1 Risk factors include age, height, smoking, stress, strenuous activity, and exposure to whole body vibration (e.g. in a car).4 Epidemiologically, sciatica displays no gender predominance, peak incidence in the fourth decade, a genetic predisposition, and an occupational predisposition (e.g. in machine operators and truck drivers).4
Sciatica is primarily diagnosed by history taking and physical examination. Patients with sciatica commonly report unilateral pain in the lumbar spine, pain or burning sensations deep in the buttocks, and paresthesia.5 Less commonly, patients report ipsilateral leg weakness. Physical examination depends on neurological testing, such as the straight leg raising test. In the straight leg raising test, the patient lays in a relaxed, supine position while the examiner lifts the leg from the posterior, flexing at the hip joint and keeping the knee in full extension. Typically, pain experienced between 30 and 70 degrees of hip flexion indicates a lumbar disc herniation.4 Overall, the diagnosis of sciatica is justified if a patient reports radiating pain in one leg and demonstrates nerve root tension or neurological deficits based on a positive result on one or more neurological tests.4
Anatomically, the sciatic nerve is comprised of the L4 through S2 nerve roots, which merge at the pelvic cavity and exit posteriorly through the sciatic foramen.5 The sciatic nerve then travels inferior and anterior to the piriformis, and posterior to the gemellus superior, gemellus inferior, obturator internus, and quadratus femoris.5 Next, the sciatic nerve enters the posterior thigh, travels to the biceps femoris, and terminates at the knee in the popliteal folsa.5 Sciatica occurs when the nerve is pinched or compressed anywhere along the aforementioned pathway. In 90% of cases, sciatica is caused by a herniated disc with associated nerve root compression.4 However, sciatica is also caused by several other pathologies, including:
Muscle spasm
Nerve root impingement
Epidural abscess
Epidural hematoma
Tumor
Spinal tuberculosis
Piriformis syndrome
The prognosis for sciatica is quite favorable, with most cases resolving in 4 to 6 weeks with no long-term consequences. For example, a randomized trial involving non-steroidal anti-inflammatory drugs showed that 60% of patients recovered within three months and 70% within 12 months.6 That said, recovery is more prolonged in severe cases involving neurological deficits. Accordingly, some studies suggest that up to 30% of patients experience pain for a year or longer.6-7 Therefore, it is advised to seek treatment to avoid chronic and recurrent pain.
Chiropractic treatment for sciatica is non-invasive, non-surgical, and drug-free. The type of treatment depends on the cause of sciatica, but may include a combination of ice therapy, ultrasound, transcutaneous electrical nerve stimulation, and spinal adjustments. Ice therapy alleviates sciatic pain by reducing inflammation.8 Ultrasound therapy involves sound waves that penetrate deep into soft tissue, which increases circulation and reduces muscles spasms, cramping, swelling, stiffness, and sciatic pain.8
In transcutaneous electrical nerve stimulation, a machine generates variable amounts of electrical current to reduce muscle spasms and alleviate pain.8 Spinal manipulation frees restricted movement of the spine by restoring misaligned vertebral bodies to their proper position in the spinal column; this alleviates inflammation, muscle spasms, and sciatic pain.8 Overall, sciatica is a debilitating condition that can significantly affect one’s quality of life. Patients displaying symptoms should seek chiropractic care to alleviate their pain and restore their quality of life.
References
1) Lagerbäck T, Fritzell P, Hägg O, Nordvall D, Lønne G, Solberg TK, Andersen MØ, Eiskjær S, Gehrchen M, Jacobs WC, van Hooff ML, Gerdhem P. Effectiveness of surgery for sciatica with disc herniation is not substantially affected by differences in surgical incidences among three countries: results from the Danish, Swedish and Norwegian spine registries. Eur Spine J. 2019 Nov;28(11):2562-2571.
2) Alrwaily M, Almutiri M, Schneider M. Assessment of variability in traction interventions for patients with low back pain: a systematic review. Chiropr Man Therap. 2018;26:35.
3) Hong X, Shi R, Wang YT, Liu L, Bao JP, Wu XT. Lumbar disc herniation treated by microendoscopic discectomy : Prognostic predictors of long-term postoperative outcome. Orthopade. 2018 Dec;47(12):993-1002.
4) Koes BW, van Tulder MW, Peul WC. Diagnosis and treatment of sciatica. BMJ. 2007;334(7607):1313–1317.
5) Delgado-López PD, Rodríguez-Salazar A, Martín-Alonso J, Martín-Velasco V. [Lumbar disc herniation: Natural history, role of physical examination, timing of surgery, treatment options and conflicts of interests]. Neurocirugia (Astur). 2017 May – Jun;28(3):124-134.
6) Weber H, Holme I, Amlie E. The natural course of acute sciatica with nerve root symptoms in a double blind placebo-controlled trial of evaluating the effect of piroxicam (NSAID). Spine 1993;18:1433-8.
7) Vroomen PCAJ, Krom MCTFM de, Slofstra PD, Knottnerus JA. Conservative treatment of sciatica: a systematic review. J Spinal Dis 2000;13:463-9.
8) Grassi R. Chiropractic Treatment of Sciatica. Remedy Health Media. Spine Universe. 2020.