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Evaluation and Treatment of Low Back Pain

A Clinically Focused Review for Primary Care Specialists
  • W. Michael Hooten
    Correspondence
    Correspondence: Address to W. Michael Hooten, MD, Department of Anesthesiology, Mayo Clinic, Charlton 145, 200 First St SW, Rochester, MN 55902.
    Affiliations
    Mayo Clinic College of Medicine and Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN
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  • Steven P. Cohen
    Affiliations
    Department of Anesthesiology and Critical Care Medicine, Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD

    Department of Anesthesiology, Department of Physical Medicine and Rehabilitation, Uniformed Services University of Health Sciences, Bethesda, MD
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      Abstract

      Low back pain (LBP) is a leading cause of disability worldwide. In the absence of a classification system for pain syndromes, classification of LBP on the basis of the distribution of pain as axial (pain generally localized to the low back) or radicular neuropathic (pain radiating to the lower extremities) is relevant to clinical practice because the distribution of pain is often a corollary of frequently occurring disease processes involving the lumbar spine. Common sources of axial LBP include the intervertebral disc, facet joint, sacroiliac joint, and paraspinal musculature, whereas common sources of radicular pain include a herniated intervertebral disc and spinal stenosis. The accuracy of historical and physical examination findings has been established for sacroiliac joint pain, radiculopathy, and lumbar spinal stenosis. However, the accuracy of similar data, so-called red flags, for identifying the underlying medical sources of LBP has been overstated. Diagnostic imaging studies can be useful, and adherence to established guidelines can protect against overuse. Multiple pharmacological trials exist for the management of LBP; however, the long-term outcomes of commonly used drugs are mixed. For carefully selected patients with axial LBP, radiofrequency denervation techniques can provide sustained pain relief. In patients with radicular pain, transforaminal epidural steroid injections may provide short-term pain relief, but neurostimulation may confer more enduring benefits of refractory symptoms. Pain-related indications for commonly performed operations include spinal decompression for radicular symptoms as well as spinal fusion or disc prosthesis for discogenic LBP. Physical modalities and psychological treatments can improve pain and functioning, but patient preferences may influence treatment adherence.

      Abbreviations and Acronyms:

      ESI (epidural steroid injection), LBP (low back pain), LSTV (lumbosacral transitional vertebra)
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      Learning Objectives: On completion of this article, you should be able to: (1) distinguish the key anatomical structures implicated in the pathogenesis of low back pain; (2) identify the clinical characteristics that differentiate axial and radicular low back pain; and (3) formulate an evidence-based treatment plan for low back pain.
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      Low back pain (LBP) is a leading cause of disability worldwide with a lifetime incidence of 51% to 84%.
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      • Maher C.G.
      The epidemiology and economic consequences of pain.
      The taxonomy of pain syndromes, including LBP, is underdeveloped, and no widely accepted single classification system currently exists.
      • Fillingim R.B.
      • Bruehl S.
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      • et al.
      The ACTTION-American Pain Society Pain Taxonomy (AAPT): an evidence-based and multidimensional approach to classifying chronic pain conditions.
      • Geurts J.W.
      Classification and management of low back pain: Is this the right direction?.
      • Henriques A.A.
      • Dussán-Sarria J.A.
      • Botelho L.M.
      • Caumo W.
      Multidimensional approach to classifying chronic pain conditions—less is more.
      However, classification of LBP based on the distribution of pain as predominately axial (pain localized to the low back area) or radicular (pain radiating to the lower extremities in a dermatomal distribution with or without accompanying LBP) is particularly relevant to primary care specialists because the distribution of pain is often a corollary of frequently occurring disease processes involving the lumbar spine.
      • DePalma M.J.
      • Ketchum J.M.
      • Saullo T.
      What is the source of chronic low back pain and does age play a role?.
      This simple classification scheme provides a clinically focused framework for organizing key historical and physical examination findings that drive the diagnostic and therapeutic decision-making processes that arise in the routine care of adults with LBP.
      • DePalma M.J.
      • Ketchum J.M.
      • Saullo T.
      What is the source of chronic low back pain and does age play a role?.
      • DePalma M.J.
      • Ketchum J.M.
      • Saullo T.R.
      Multivariable analyses of the relationships between age, gender, and body mass index and the source of chronic low back pain.
      Therefore, the purpose of this review was to provide a clinically focused approach for the evaluation and treatment of chronic LBP for primary care specialists.

      Methods

      Similar to previously published search strategies,
      • Cohen S.P.
      Epidemiology, diagnosis, and treatment of neck pain.
      databases of MEDLINE using the PubMed and Ovid platforms as well as the Cochrane Database of Systematic Reviews were searched using the key words low back pain, lumbar spine pain, and lumbar radiculopathy with no date restrictions. Key words pertaining to specific topics (eg, lumbar spinal stenosis, physical examination, therapeutic spinal injections, and analgesic medication) were cross-referenced with the initial search terms using the identified databases. Search terms were cross-referenced with review articles, and additional articles were identified by manually searching reference lists.

      Epidemiology and Natural Course

      Epidemiology

      The estimated prevalence of LBP varies according to the surveillance period and specific type of pain. For example, in a systematic review,
      • Hoy D.
      • Brooks P.
      • Blyth F.
      • Buchbinder R.
      The epidemiology of low back pain.
      the point prevalence of LBP was 18.3%, the 1-month rate was 30.8%, and the mean annual prevalence was 38.0%. In a more recent systematic review
      • Hoy D.
      • Bain C.
      • Williams G.
      • et al.
      A systematic review of the global prevalence of low back pain.
      in which chronic LBP was defined as pain lasting longer than 12 weeks, the prevalence ranged from 5.9% to 18.1%. The 1-year incidence of an initial episode of LBP ranges from 6.3% to 26.2%, and estimates of recurrence at 1 year range from 24% to 80%.
      • Henschke N.
      • Kamper S.J.
      • Maher C.G.
      The epidemiology and economic consequences of pain.
      • Hoy D.
      • Brooks P.
      • Blyth F.
      • Buchbinder R.
      The epidemiology of low back pain.
      • Taylor J.B.
      • Goode A.P.
      • George S.Z.
      • Cook C.E.
      Incidence and risk factors for first-time incident low back pain: a systematic review and meta-analysis.
      Neuropathic pain, defined as pain resulting from a lesion or disease affecting the somatosensory system, can be an important characteristic of LBP especially in individuals with a herniated disc causing nerve root irritation and lumbar spinal stenosis. In individuals with predominately chronic axial LBP, questionnaires designed to detect the distinguishing characteristics of neuropathic pain have found that between 17% and 55% of individuals have pain that is primarily neuropathic in nature, with a median rate of 41%.
      • Freynhagen R.
      • Baron R.
      • Gockel U.
      • Tölle T.R.
      painDETECT: a new screening questionnaire to identify neuropathic components in patients with back pain.
      • El Sissi W.
      • Arnaout A.
      • Chaarani M.W.
      • et al.
      Prevalence of neuropathic pain among patients with chronic low-back pain in the Arabian Gulf Region assessed using the leeds assessment of neuropathic symptoms and signs pain scale.
      • Beith I.D.
      • Kemp A.
      • Kenyon J.
      • Prout M.
      • Chestnut T.J.
      Identifying neuropathic back and leg pain: a cross-sectional study.
      • Kaki A.M.
      • El-Yaski A.Z.
      • Youseif E.
      Identifying neuropathic pain among patients with chronic low-back pain: use of the Leeds Assessment of Neuropathic Symptoms and Signs pain scale.
      • Hassan A.E.
      • Saleh H.A.
      • Baroudy Y.M.
      • et al.
      Prevalence of neuropathic pain among patients suffering from chronic low back pain in Saudi Arabia.
      • Cohen S.P.
      • Bicket M.C.
      • Jamison D.
      • Wilkinson I.
      • Rathmell J.P.
      Epidural steroids: a comprehensive, evidence-based review.
      This distinction is important because neuropathic pain may be associated with greater levels of physical and psychological dysfunction as compared with other types of pain.
      • Smith B.H.
      • Torrance N.
      • Bennett M.I.
      • Lee A.J.
      Health and quality of life associated with chronic pain of predominantly neuropathic origin in the community.
      The incidence of new-onset radicular pain ranges from 1.5% to 18.5%,
      • Younes M.
      • Béjia I.
      • Aguir Z.
      • et al.
      Prevalence and risk factors of disk-related sciatica in an urban population in Tunisia.
      • Matsudaira K.
      • Kawaguchi M.
      • Isomura T.
      • et al.
      Identification of risk factors for new-onset sciatica in Japanese workers: findings from the Japan epidemiological research of Occupation-related Back pain study.
      and the incidence of lumbar spinal stenosis has been estimated to be 5 per 100,000 people.
      • Melancia J.L.
      • Francisco A.F.
      • Antunes J.L.
      Spinal stenosis.

      Natural Course

      Axial LBP

      Although most episodes of acute LBP will resolve, a substantial proportion of patients will develop chronic or recurrent pain. A large study
      • Henschke N.
      • Maher C.G.
      • Refshauge K.M.
      • et al.
      Prognosis in patients with recent onset low back pain in Australian primary care: inception cohort study.
      that followed 973 people with acute axial LBP found that 28% had not fully recovered 12 months after their initial consultation. Factors associated with persistence included older age, greater baseline pain and dysfunction, depression, fear of pain persistence, and ongoing compensation claims.
      • Henschke N.
      • Maher C.G.
      • Refshauge K.M.
      • et al.
      Prognosis in patients with recent onset low back pain in Australian primary care: inception cohort study.
      A systematic review
      • Itz C.J.
      • Geurts J.W.
      • van Kleef M.
      • Nelemans P.
      Clinical course of non-specific low back pain: a systematic review of prospective cohort studies set in primary care.
      comprising 11 studies that followed individuals with axial LBP less than 3 months in duration who sought evaluation in a primary care setting yielded less favorable findings. Itz et al
      • Itz C.J.
      • Geurts J.W.
      • van Kleef M.
      • Nelemans P.
      Clinical course of non-specific low back pain: a systematic review of prospective cohort studies set in primary care.
      found that one-third of individuals recovered within 3 months, but 65% continued to experience persistent pain at 1-year follow-up. This suggests that individuals who do not recover within 3 months are at increased risk of developing chronic axial LBP.

      Radicular Pain

      Several studies have sought to determine the natural course of lumbosacral radiculopathy. In one of the earliest studies examining the clinical course in individuals with sciatica, Hakelius
      • Hakelius A.
      Prognosis in sciatica: a clinical follow-up of surgical and non-surgical treatment.
      found that 58% of 38 patients with clinical symptoms and positive contrast myelography were symptom-free within 30 days and 88% were symptom-free after 6 months. A retrospective study by Saal and Saal
      • Saal J.A.
      • Saal J.S.
      Nonoperative treatment of herniated lumbar intervertebral disc with radiculopathy: an outcome study.
      reported that among 52 patients with signs and symptoms of lumbosacral radiculopathy confirmed by electrodiagnostic testing who received aggressive conservative care, 96% experienced good (n=35) or excellent (n=15) outcomes at a mean follow-up period of 31 months. In both the treatment (piroxicam) and placebo-control arms of a randomized study evaluating 208 patients with acute sciatica, Weber et al
      • Weber H.
      • Holme I.
      • Amlie E.
      The natural course of acute sciatica with nerve root symptoms in a double-blind placebo-controlled trial evaluating the effect of piroxicam.
      found that 64 patients (30%) continued to report significant pain after 3 months, with few patients experiencing resolution between 3-month and 1-year follow-up. In another double-blind study
      • Fraser R.D.
      Chymopapain for the treatment of intervertebral disc herniation: the final report of a double-blind study.
      evaluating chymopapain chemonucleolysis, 11 out of 30 patients 37% of the placebo-controlled group experienced a good outcome at 6 weeks, which increased to 60% by 6 months. In summary, whereas most episodes of new-onset radicular pain will resolve without aggressive treatment, 15% to 40% of individuals will experience early (<1 year) or frequent recurrences of symptoms.
      • Weber H.
      • Holme I.
      • Amlie E.
      The natural course of acute sciatica with nerve root symptoms in a double-blind placebo-controlled trial evaluating the effect of piroxicam.
      • Suri P.
      • Rainville J.
      • Hunter D.J.
      • Li L.
      • Katz J.N.
      Recurrence of radicular pain or back pain after nonsurgical treatment of symptomatic lumbar disk herniation.
      • Casey E.
      Natural history of radiculopathy.
      The observation that most cases of acute radiculopathy improve within several months is consistent with radiological studies
      • Saal J.A.
      Natural history and nonoperative treatment of lumbar disc herniation.
      • Benoist M.
      The natural history of lumbar disc herniation and radiculopathy.
      that found that approximately two-thirds of herniated lumbar discs undergo significant (>50%) resorption within 1 year.
      Several instruments have been developed to predict which patients may be at risk for developing chronic LBP after a back injury, with one of the more common being the Acute Low Back Pain Screening Questionnaire, which was subsequently modified to include all musculoskeletal conditions.
      • Linton S.J.
      • Boersma K.
      Early identification of patients at risk of developing a persistent back problem: the predictive validity of the Orebro Musculoskeletal Pain Questionnaire.
      A systematic review
      • Sattelmayer M.
      • Lorenz T.
      • Röder C.
      • Hilfiker R.
      Predictive value of the Acute Low Back Pain Screening Questionnaire and the Örebro Musculoskeletal Pain Screening Questionnaire for persisting problems.
      found that the pool sensitivity of this questionnaire was 0.59 and the specificity was 0.77.

      Lumbar Spinal Stenosis

      Lumbar spinal stenosis occurs when the vertebral canal is narrowed by surrounding bone and soft tissues, leading to compression of neural structures including the spinal nerve roots. Spinal stenosis is not a single disease process; rather, it is multifactorial and generally the result of a combination of anatomical changes including intervertebral disc protrusion or herniation, facet joint hypertrophy, spondylolisthesis (forward displacement of a vertebra), congenital narrowing of the vertebral canal, or hypertrophy/buckling of the ligamentum flavum. Consequently, the natural history of lumbar spinal stenosis is less auspicious, though only a minority of patients develop progressively worsening symptoms. At a mean follow-up period of 11.1 years, Minamide et al
      • Minamide A.
      • Yoshida M.
      • Maio K.
      The natural clinical course of lumbar spinal stenosis: a longitudinal cohort study over a minimum of 10 years.
      found that similar proportions of 34 patients with lumbar spinal stenosis treated conservatively experienced improvement, no change, or worsening of symptoms. A cohort study
      • Micankova Adamova B.
      • Vohanka S.
      • Dusek L.
      • Jarkovsky J.
      • Bednarik J.
      Prediction of long-term clinical outcome in patients with lumbar spinal stenosis.
      evaluating 56 patients with symptomatic mild-to-moderate lumbar spinal stenosis symptoms who were treated conservatively found that 34 patients (60.7%) had a stable or improved clinical status at a median follow-up period of 88 months. These findings are consistent with several older studies
      • Johnsson K.E.
      • Udén A.
      • Rosén I.
      The effect of decompression on the natural course of spinal stenosis: a comparison of surgically treated and untreated patients.
      • Johnsson K.E.
      • Rosén I.
      • Udén A.
      The natural course of lumbar spinal stenosis.
      exhibiting that most patients with conservatively treated spinal stenosis will report either stable or improved symptoms at least 3 years after the presentation. In a partially randomized study, Amundsen et al
      • Amundsen T.
      • Weber H.
      • Nordal H.J.
      • Magnaes B.
      • Abdelnoor M.
      • Lilleâs F.
      Lumbar spinal stenosis: conservative or surgical management? A prospective 10-year study.
      found that 57% of a nonrandomized cohort (n=50) with mild symptoms obtained a good outcome at 4-year follow-up whereas 44% of 18 randomized nonsurgically treated patients had a good outcome at 4 years.
      In contrast to an acute herniated disc that may resolve over time, the chronic degenerative and bony changes that characterize axial LBP and spinal stenosis do not generally regress. Thus, the anatomical changes that predispose to the development of axial LBP and spinal stenosis may in part explain the discrepancies observed in the overall prognosis of these patients.

      Clinically Oriented Anatomy of the Lumbar Spine

      Although the anatomy of the lumbar spine is complex, several key anatomical structures contribute to commonly encountered clinical problems including the vertebral body, intervertebral disc, facet joint, paraspinal muscles, and ligamentum flavum. The lumbar spine is composed of 5 vertebrae; however, estimates of the prevalence of lumbosacral transitional vertebrae (LSTVs) range from 7% to 30%.
      • Konin G.P.
      • Walz D.M.
      Lumbosacral transitional vertebrae: classification, imaging findings, and clinical relevance.
      The transverse processes of the fifth lumbar (L5) vertebral body may be broad and elongated, which can lead to complete sacral fusion. The assimilation of the L5 vertebra into the sacrum is termed sacralization of L5. Conversely, the first sacral (S1) vertebra may form articulations with the S2 vertebral body and even have well-formed lumbar-type facet joints and a lumbar-sized intervertebral disc. The term lumbarization refers to an S1 vertebra that has features of a lumbar vertebra. The correct identification of LSTVs is important to avoid surgical and procedural errors attributed to inaccurate vertebral body enumeration and to ensure accurate correlation of clinical symptoms. One approach to enumerating the lumbar vertebrae involves identifying the most caudal rib (12th rib) that articulates with the 12th thoracic vertebral body (T12). The vertebral body immediately caudal to T12 is designated L1, and the remainder of lumbar vertebrae are enumerated sequentially in the caudal direction. Although an LSTV has been associated with radicular pain because of compression of spinal nerve roots,
      • Taskaynatan M.A.
      • Izci Y.
      • Ozgul A.
      • Hazneci B.
      • Dursun H.
      • Kalyon T.A.
      Clinical significance of congenital lumbosacral malformations in young male population with prolonged low back pain.
      • Otani K.
      • Konno S.
      • Kikuchi S.
      Lumbosacral transitional vertebrae and nerve-root symptoms.
      studies that have sought to establish an association between LSTVs and the occurrence of axial LBP have been mixed, with only certain types of LSTVs (eg, pseudarthrosis) being linked to LBP.
      • Tang M.
      • Yang X.F.
      • Yang S.W.
      • et al.
      Lumbosacral transitional vertebra in a population-based study of 5860 individuals: prevalence and relationship to low back pain.
      • Nardo L.
      • Alizai H.
      • Virayavanich W.
      • et al.
      Lumbosacral transitional vertebrae: association with low back pain.
      The intervertebral disc is an avascular fibrocartilaginous structure that allows movement between adjacent vertebral bodies (Figure 1). Each lumbar intervertebral disc is approximately 4 cm in diameter and 7 to 10 mm in thickness,
      • Roberts S.
      • Menage J.
      • Urban J.P.
      Biochemical and structural properties of the cartilage end-plate and its relation to the intervertebral disc.
      and it is composed of an outer annulus fibrosus and an inner nucleus pulposus. The annulus is a dense concentric ring of layered collagen fibers that surrounds the nucleus and resists tensile forces. The nucleus pulposus contains collagen and elastin fibers embedded within a hydrated proteoglycan gel. Disc degeneration is associated with annular tears and dehydration of the nucleus pulposus, which can lead to decreased disc height, impaired mechanical function, rupture, and compression of spinal nerve roots (Figure 2). In addition, nerve and vascular ingrowth into the disc and exposure of these nerves to inflammatory mediators have been associated with axial LBP.
      • Simon J.
      • McAuliffe M.
      • Shamim F.
      • Vuong N.
      • Tahaei A.
      Discogenic low back pain.
      • Kallewaard J.W.
      • Terheggen M.A.
      • Groen G.J.
      • et al.
      15. Discogenic low back pain.
      Figure thumbnail gr1
      Figure 1Intervertebral disc structure.
      Figure thumbnail gr2
      Figure 2A, Lateral view of the potential effects of disc bulging and degenerative changes on spinal nerve roots. B, Axial view of a ruptured lumbar intervertebral disc.
      Lumbar facet joints, also referred to as the zygapophysial joints, are true synovial joints formed by the superior and inferior articulating processes of 2 adjacent vertebrae (Figure 3). The inferior aspect of each lumbar facet joint is innervated by the medial branch of the posterior primary rami at the same level of the facet joint, and the superior aspect is innervated by the medial branch from 1 level above. This dual innervation is important when considering targeted diagnostic and interventional therapies for lumbar facet pain. From a biomechanical perspective, the 2 facet joints and the intervertebral disc at each spinal level are interdependent and form what is referred to as a motion segment, otherwise termed the three-joint complex.
      • Cohen S.P.
      • Raja S.N.
      Pathogenesis, diagnosis, and treatment of lumbar zygapophysial (facet) joint pain.
      In this manner, the lumbar spine can be conceptualized as a stacked series of motion segments. Whereas the intervertebral disc is the principal weight- or load-bearing structure of each motion segment, the role of the facet joints is to limit torsion and resist forward displacement of the vertebral segment. However, in the setting of degenerative disc disease and associated disc space narrowing, the total load transmitted to the facet joint increases and can sometimes exceed 50% of the total load placed on the vertebral segment.
      • Yang K.H.
      • King A.I.
      Mechanism of facet load transmission as a hypothesis for low-back pain.
      • Adams M.A.
      • Hutton W.C.
      The mechanical function of the lumbar apophyseal joints.
      Pathophysiologically, osteoarthritic changes involving the lumbar facet joints are common and include joint space narrowing due to degenerative thinning of the cartilage, presence of inflammatory cells and mediators, increased vascularization, subchondral bone remodeling, and osteophyte formation, which can contribute to axial LBP and spinal stenosis.
      • Izzo R.
      • Guarnieri G.
      • Guglielmi G.
      • Muto M.
      Biomechanics of the spine. Part I: spinal stability.
      • Gellhorn A.C.
      • Katz J.N.
      • Suri P.
      Osteoarthritis of the spine: the facet joints.
      These osteoarthritic changes, particularly osteophyte formation, can contribute to neural foraminal stenosis and compression of the exiting nerve root, which can lead to the development of radicular pain.
      Figure thumbnail gr3
      Figure 3Anatomy and innervation of the lumbar facet joint. Also depicted are bilateral fractures of the pars interarticularis (pars defect) and an osteoarthritic facet joint.
      The ligamentum flavum extends along the posterior aspect of the vertebral column and connects the laminae of the adjacent vertebrae (Figure 4). The ligamentum flavum is 2- to 3-mm thick and is composed of elastin and collagen fibers in a 2:1 ratio; the elastin fibers provide elasticity, and the collagen fibers provide tensile strength and stability. Hypertrophy of the ligamentum flavum is multifactorial and has been associated with older age, mechanical stress, increased body mass index (calculated as the weight in kilograms divided by the height in meters squared), and alterations in cytokine and proteinase inhibitor concentrations.
      • Kosaka H.
      • Sairyo K.
      • Biyani A.
      • et al.
      Pathomechanism of loss of elasticity and hypertrophy of lumbar ligamentum flavum in elderly patients with lumbar spinal canal stenosis.
      • Sairyo K.
      • Biyani A.
      • Goel V.
      • et al.
      Pathomechanism of ligamentum flavum hypertrophy: a multidisciplinary investigation based on clinical, biomechanical, histologic, and biologic assessments.
      Ligamentum flavum hypertrophy can be an important contributor to the development of spinal stenosis, especially when it occurs in conjunction with other disease processes that narrow the spinal canal, including facet joint arthropathy and disc protrusions.
      • Szpalski M.
      • Gunzburg R.
      Lumbar spinal stenosis in the elderly: an overview.
      Figure thumbnail gr4
      Figure 4Cross-sectional view of the lumbar spine, depicting ligamentous structures.
      Multiple muscles affect lumbar spine function and can be categorized into 3 major anatomical groups relative to the torso: the posterior, anterior, and lateral groups (Figure 5).
      • Bartleson J.
      • Deen G.H.
      Spine Disorders: Medical and Surgical Management.
      Together, these 3 muscle groups control movement of the spine, contribute to the stabilization of the vertebral column, and provide proprioceptive feedback.
      • Leinonen V.
      • Kankaanpää M.
      • Luukkonen M.
      • et al.
      Lumbar paraspinal muscle function, perception of lumbar position, and postural control in disc herniation-related back pain.
      The posterior group, composed of superficial (ie, erector spinae and serratus posterior inferior), intermediate (ie, longissimus thoracis), and deep (ie, multifidus and quadratus lumborum) layers, arise from the transverse and spinous processes of the vertebrae and insert on the iliac crests and sacrum. The deeper muscles span fewer vertebrae compared with the more superficial muscles, and the muscles more adjacent to midline are of greater diameter. The muscles of the posterior group are responsible for extending, lateral bending, and torsion of the spine. The anterior group is chiefly composed of the abdominal wall (ie, rectus abdominis, external oblique, and internal oblique) and is primarily responsible for flexion of the spine, but these muscles also contribute to lateral bending and torsional movement. The lateral group includes the psoas and iliacus muscles. The psoas muscle arises from the lateral aspects of the lumbar vertebrae, and the iliacus muscles arise from the anterior ilium and lateral sacrum. These 2 muscles join as they move laterally to insert on the lesser trochanter of the femur and are often referred to as the iliopsoas muscle. The iliopsoas is a powerful flexor of the thigh and works to maintain an upright and erect posture. Current evidence suggests that the cross-sectional area and density of paraspinal muscles are reduced in patients with LBP,
      • Chan S.T.
      • Fung P.K.
      • Ng N.Y.
      • et al.
      Dynamic changes of elasticity, cross-sectional area, and fat infiltration of multifidus at different postures in men with chronic low back pain.
      • Kalichman L.
      • Hodges P.
      • Li L.
      • Guermazi A.
      • Hunter D.J.
      Changes in paraspinal muscles and their association with low back pain and spinal degeneration: CT study.
      and alterations in muscle activation and fat infiltration of the paraspinal muscles have been observed in these patients.
      • Silfies S.P.
      • Squillante D.
      • Maurer P.
      • Westcott S.
      • Karduna A.R.
      Trunk muscle recruitment patterns in specific chronic low back pain populations.
      • Teichtahl A.J.
      • Urquhart D.M.
      • Wang Y.
      • et al.
      Physical inactivity is associated with narrower lumbar intervertebral discs, high fat content of paraspinal muscles and low back pain and disability.
      In addition, reduced paraspinal muscle density has been associated with facet joint osteoarthritis, spondylolisthesis, and disc space narrowing.
      • Kalichman L.
      • Hodges P.
      • Li L.
      • Guermazi A.
      • Hunter D.J.
      Changes in paraspinal muscles and their association with low back pain and spinal degeneration: CT study.
      Figure thumbnail gr5
      Figure 5Muscle groups that contribute to lumbar spine function.

      History and Physical Examination

      Significance of “Red Flag” Symptoms

      A critical aspect in the evaluation of axial or radicular pain is to identify nonmusculoskeletal diseases that may be responsible for the patients' symptoms. Although the differential diagnosis of LBP is broad, most nonmusculoskeletal disease states can be categorized as neoplastic, inflammatory, visceral (which includes pelvic and retroperitoneal structures), infectious, vascular, endocrine, and traumatic (Table 1).
      • Deyo R.A.
      • Weinstein J.N.
      Low back pain.
      The risk factors, historical features, and physical examination findings associated with nonmusculoskeletal diseases are widely referred to as red flags, but the accuracy, or risk-benefit ratio, of many previously recognized red flag signs and symptoms has been called into question.
      • Chou R.
      • Qaseem A.
      • Snow V.
      • et al.
      Clinical Efficacy Assessment Subcommittee of the American College of Physicians; American College of Physicians; American Pain Society Low Back Pain Guidelines Panel
      Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society.
      • Underwood M.
      • Buchbinder R.
      Red flags for back pain.
      In a prospective study
      • Henschke N.
      • Maher C.G.
      • Refshauge K.M.
      • et al.
      Prevalence of and screening for serious spinal pathology in patients presenting to primary care settings with acute low back pain.
      that involved 1172 consecutive patients receiving primary care for acute LBP, 11 patients (0.9%) were identified as having “serious spinal pathology” including 8 with vertebral compression fractures, 2 with inflammatory arthritides, and 1 with cauda equina syndrome. Although the prevalence of serious pathology was low, 4 clinical factors were statistically significantly associated with vertebral compression fractures, including female sex, age greater than 70 years, trauma, and prolonged use of corticosteroids.
      • Henschke N.
      • Maher C.G.
      • Refshauge K.M.
      • et al.
      Prevalence of and screening for serious spinal pathology in patients presenting to primary care settings with acute low back pain.
      A set of similar red flag indicators were identified in 2 systematic reviews
      • Downie A.
      • Williams C.M.
      • Henschke N.
      • et al.
      Red flags to screen for malignancy and fracture in patients with low back pain: systematic review.
      • Williams C.M.
      • Henschke N.
      • Maher C.G.
      • et al.
      Red flags to screen for vertebral fracture in patients presenting with low-back pain.
      that investigated the accuracy of various clinical factors used to screen for vertebral compression fractures and spinal malignant neoplasm (Table 1). In clinical practice, the use of red flag indicators should supplement but not supplant clinical judgment on the evaluation of nonmusculoskeletal disease processes.
      Table 1Medical (Nonmusculoskeletal) Causes of Low Back Pain and Posttest Probability (PTP) of Red Flag Signs to Detect Fracture and Malignancy
      Medical (nonmusculoskeletal) causes of low back pain
      Neoplastic
      Data from N Engl J Med.61
      Inflammatory
      Data from N Engl J Med.61
      Visceral
      Data from N Engl J Med.61
      Infectious
      Data from N Engl J Med.61
      Vascular
      Data from N Engl J Med.61
      Endocrine
      Data from N Engl J Med.61
      Traumatic
      Data from N Engl J Med.61
      Metastatic carcinomaAnkylosing spondylitisEndometriosisOsteomyelitisAortic aneurysmOsteoporotic fracturesVertebral fracture
      Multiple myelomaPsoriatic spondylitisProstatitisEpidural abscessAortic dissectionPaget diseaseRib fracture
      LymphomaRheumatoid arthritisNephrolithiasisDiscitisSpinal hemangiomaPelvic fracture
      LeukemiaReiter syndromeAortic aneurysmHerpes zosterInferior vena cava obstructionHip fracture
      Spinal cord tumorsEnteropathic spondylitisPancreatitisPyelonephritisSickle cell crisis
      PTP of red flag signs to detect vertebral compression fracture
      Red flag signPTP (95% CI)
      Data from BMJ65 and Cochrane Database Syst Rev.66
      Contusion or abrasion62% (49%-74%)
      Prolonged corticosteroid use33% (10%-67%)
      Severe trauma11% (8%-16%)
      Older age9% (3%-25%)
      Multiple signs present
       Combination of any 3
      Female90% (34%-99%)
      Age >70 y
      Severe trauma
      Prolonged corticosteroid use
      PTP of red flag signs to detect spinal malignancy
      Red flag signPTP (95% CI)
      Data from BMJ65 and Cochrane Database Syst Rev.66
      History of malignancy33% (22%-46%)
      a Data from N Engl J Med.
      • Deyo R.A.
      • Weinstein J.N.
      Low back pain.
      b Data from BMJ
      • Downie A.
      • Williams C.M.
      • Henschke N.
      • et al.
      Red flags to screen for malignancy and fracture in patients with low back pain: systematic review.
      and Cochrane Database Syst Rev.
      • Williams C.M.
      • Henschke N.
      • Maher C.G.
      • et al.
      Red flags to screen for vertebral fracture in patients presenting with low-back pain.

      Axial LBP

      The differential diagnosis of axial LBP is broad but commonly involves lumbar spine structures that include the intervertebral discs, facet joints, sacroiliac joints, and paraspinal musculature. Although nonspecific,
      • Malik K.M.
      • Cohen S.P.
      • Walega D.R.
      • Benzon H.T.
      Diagnostic criteria and treatment of discogenic pain: a systematic review of recent clinical literature.
      some historical features and characteristic signs and symptoms associated with axial LBP may be helpful in determining the source of pain. The intervertebral disc can be a source of pain in up to 40% of patients with axial LBP. These patients tend to be younger (age <45 years), and though the onset tends to be insidious in most cases, in some instances an inciting event may be described (ie, lifting, bending, and twisting).
      • DePalma M.J.
      • Ketchum J.M.
      • Saullo T.
      What is the source of chronic low back pain and does age play a role?.
      • Simon J.
      • McAuliffe M.
      • Shamim F.
      • Vuong N.
      • Tahaei A.
      Discogenic low back pain.
      • Schwarzer A.C.
      • Aprill C.N.
      • Derby R.
      • Fortin J.
      • Kine G.
      • Bogduk N.
      The prevalence and clinical features of internal disc disruption in patients with chronic low back pain.
      Discogenic LBP is often worsened by activities that load the spine, and a history of sitting intolerance and improvement of pain with recumbency are often reported. Patients will often localize pain to the midline of the spine,
      • Depalma M.J.
      • Ketchum J.M.
      • Trussell B.S.
      • Saullo T.R.
      • Slipman C.W.
      Does the location of low back pain predict its source?.
      but pain can be referred to the upper thigh and up to 20% will experience pain distal to the knee.
      • Kallewaard J.W.
      • Terheggen M.A.
      • Groen G.J.
      • et al.
      15. Discogenic low back pain.
      • Ohnmeiss D.D.
      • Vanharanta H.
      • Ekholm J.
      Relation between pain location and disc pathology: a study of pain drawings and CT/discography.
      Although no physical examination findings can accurately discriminate patients with discogenic pain,
      • Schwarzer A.C.
      • Aprill C.N.
      • Derby R.
      • Fortin J.
      • Kine G.
      • Bogduk N.
      The prevalence and clinical features of internal disc disruption in patients with chronic low back pain.
      greater midline tenderness may be an indicator in some patients.
      • Depalma M.J.
      • Ketchum J.M.
      • Trussell B.S.
      • Saullo T.R.
      • Slipman C.W.
      Does the location of low back pain predict its source?.
      Axial LBP attributed to the lumbar facet joints is estimated to affect approximately 15% to 30% of patients.
      • DePalma M.J.
      • Ketchum J.M.
      • Saullo T.
      What is the source of chronic low back pain and does age play a role?.
      • Schwarzer A.C.
      • Wang S.C.
      • Bogduk N.
      • McNaught P.J.
      • Laurent R.
      Prevalence and clinical features of lumbar zygapophysial joint pain: a study in an Australian population with chronic low back pain.
      • Schwarzer A.C.
      • Aprill C.N.
      • Derby R.
      • Fortin J.
      • Kine G.
      • Bogduk N.
      Clinical features of patients with pain stemming from the lumbar zygapophysial joints: is the lumbar facet syndrome a clinical entity?.
      Although numerous studies have attempted to identify the historical and physical examination findings associated with lumbar facet pain, no discrete set of clinical markers has been delineated.
      • Cohen S.P.
      • Raja S.N.
      Pathogenesis, diagnosis, and treatment of lumbar zygapophysial (facet) joint pain.
      However, the onset of lumbar facet pain is generally insidious and it occurs more frequently in older adults (age >65 years).
      • DePalma M.J.
      • Ketchum J.M.
      • Saullo T.
      What is the source of chronic low back pain and does age play a role?.
      Lumbar facet pain is generally worsened by prolonged standing and relieved with sitting or recumbency, which decreases the load on the joints.
      • Laslett M.
      • McDonald B.
      • Aprill C.N.
      • Tropp H.
      • Oberg B.
      Clinical predictors of screening lumbar zygapophyseal joint blocks: development of clinical prediction rules.
      In some patients, pain may be localized to the paraspinal region with or without radiation to the groin, thigh, or occasionally distal to the knee.
      • Cohen S.P.
      • Raja S.N.
      Pathogenesis, diagnosis, and treatment of lumbar zygapophysial (facet) joint pain.
      • Depalma M.J.
      • Ketchum J.M.
      • Trussell B.S.
      • Saullo T.R.
      • Slipman C.W.
      Does the location of low back pain predict its source?.
      On physical examination, no test is considered to be sensitive for identifying a painful facet joint. Although small and methodologically flawed studies suggested that pain with extension and axial rotation was indicative of facet arthropathy, diagnostic studies using double local anesthetic and placebo-controlled facet blocks, cadaveric studies using infrared markers, and correlative studies evaluating lumbar facet radiofrequency denervation outcomes have all refuted this assertion.
      • Schwarzer A.C.
      • Aprill C.N.
      • Derby R.
      • Fortin J.
      • Kine G.
      • Bogduk N.
      Clinical features of patients with pain stemming from the lumbar zygapophysial joints: is the lumbar facet syndrome a clinical entity?.
      • Ianuzzi A.
      • Little J.S.
      • Chiu J.B.
      • Baitner A.
      • Kawchuk G.
      • Khalsa P.S.
      Human lumbar facet joint capsule strains: I. During physiological motions.
      • Revel M.
      • Poiraudeau S.
      • Auleley G.R.
      • et al.
      Capacity of the clinical picture to characterize low back pain relieved by facet joint anesthesia: proposed criteria to identify patients with painful facet joints.
      • Cohen S.P.
      • Hurley R.W.
      • Christo P.J.
      • Winkley J.
      • Mohiuddin M.M.
      • Stojanovic M.P.
      Clinical predictors of success and failure for lumbar facet radiofrequency denervation.
      Sacroiliac joint pain occurs in 15% and 30% of individuals with axial LBP
      • Depalma M.J.
      • Ketchum J.M.
      • Trussell B.S.
      • Saullo T.R.
      • Slipman C.W.
      Does the location of low back pain predict its source?.
      • Maigne J.Y.
      • Aivaliklis A.
      • Pfefer F.
      Results of sacroiliac joint double block and value of sacroiliac pain provocation tests in 54 patients with low back pain.
      and is associated with a specific inciting event in 40% and 50% of occurrences; motor vehicle collisions and falls are 2 of the most common causes.
      • Cohen S.P.
      • Chen Y.
      • Neufeld N.J.
      Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment.
      Patients will often report pain in the gluteal or paraspinal (below the fifth lumbar vertebra) regions with or without radiation to the thigh, but up to 28% of patients may have referral of pain distal to the knee.
      • Cohen S.P.
      • Chen Y.
      • Neufeld N.J.
      Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment.
      • Slipman C.W.
      • Jackson H.B.
      • Lipetz J.S.
      • Chan K.T.
      • Lenrow D.
      • Vresilovic E.J.
      Sacroiliac joint pain referral zones.
      Although discogenic pain is often characterized by sitting intolerance, sacroiliac joint pain may be worsened during transitional movements, such as rising from a sitting position.
      • Young S.
      • Aprill C.
      • Laslett M.
      Correlation of clinical examination characteristics with three sources of chronic low back pain.
      On physical examination, previous studies
      • Laslett M.
      • Aprill C.N.
      • McDonald B.
      • Young S.B.
      Diagnosis of sacroiliac joint pain: validity of individual provocation tests and composites of tests.
      • van der Wurff P.
      • Buijs E.J.
      • Groen G.J.
      A multitest regimen of pain provocation tests as an aid to reduce unnecessary minimally invasive sacroiliac joint procedures.
      • Szadek K.M.
      • van der Wurff P.
      • van Tulder M.W.
      • Zuurmond W.W.
      • Perez R.S.
      Diagnostic validity of criteria for sacroiliac joint pain: a systematic review.
      suggest that a combination of physical maneuvers rather than a single test can accurately identify patients with sacroiliac joint pain (Table 2). In the differential diagnosis of sacroiliac joint pain, it is important to rule out piriformis muscle syndrome.
      • Michel F.
      • Decavel P.
      • Toussirot E.
      • et al.
      Piriformis muscle syndrome: diagnostic criteria and treatment of a monocentric series of 250 patients.
      The piriformis muscle originates from the inner surface of the sacrum and attaches to the greater trochanter of the femur. Unilateral or bilateral buttock pain with radiation in an L5 or S1 dermatomal distribution (when impingement on the sciatic nerve is present) is characteristic, and pain intensity typically fluctuates throughout the day.
      • Michel F.
      • Decavel P.
      • Toussirot E.
      • et al.
      Piriformis muscle syndrome: diagnostic criteria and treatment of a monocentric series of 250 patients.
      On physical examination, transgluteal buttock tenderness can often be elicited, pain can sometimes be provoked by maneuvers that stretch the muscle (eg, adduction and internal rotation of the hip), and the straight leg raising test result is typically negative, which help distinguish piriformis muscle syndrome from radicular pain. A digital rectal examination, which may be significant for tenderness, can aid in the diagnosis.
      Table 2Accuracy of Physical Examination Tests for Sacroiliac Joint–Related Pain, Lumbar Radiculopathy, and Lumbar Spinal Stenosis
      Pain problemTestDescriptionSensitivity (95% CI)Specificity (95% CI)
      Sacroiliac joint pain
      Data from Man Ther,81 Arch Phys Med Rehabil,82 and J Pain.83
      CompressionCompression of the iliac crest in the lateral positionIf 3 or more tests reproduce pain:
      DistractionDownward pressure on the anterior superior iliac crestSensitivity range, 78%-79%
      Patrick (FABER test)Flexion abduction external rotation of the thigh and hipSpecificity range, 85%-94%
      GaenslenHyperextension of the leg on the affected side
      Thigh trustAdduction of the flexed hip on the affected side
      Fortin fingerPain localized 1 fingerbreadth of the posterior iliac crest
      GilletFlexion of the leg toward the chest while standing
      Lumbar radiculopathy
      Data from J Neurol90 and Cochrane Database Syst Rev.91
      Straight leg raisingPatient supine and hip flexed with knee extended64% (56%-71%)57% (47%-66%)
      Cross straight leg raisingPain with passive extension of the contralateral leg28% (22%-35%)90% (85%-94%)
      Muscle weaknessDuring ankle dorsiflexion or extension of the great toe27% (20%-37%)93% (88%-97%)
      Impaired reflexesAchilles tendon (S1 radiculopathy)15% (9%-21%)93% (88%-97%)
      Patellar tendon (L4 radiculopathy)15% (9%-21%)75% (55%-89%)
      Sensory deficitsReduced tactile sensation, tingling, and numbness28% (21%-36%)66% (56%-74%)
      Forward flexionPain with bending forward in the standing position45% (37%-53%)74% (65%-81%)
      Lumbar spinal stenosis
      Data from Arthritis Rheum.92
      RombergImbalance when standing with feet together and eyes closed39% (24%-54%)91% (81%-100%)
      Gait abnormalityWide-based gait43% (28%-58%)97% (91%-100%)
      Spinal flexionNo pain with lumbar flexion79% (67%-91%)44% (27%-61%)
      Spinal extensionThigh pain with 30-s lumbar extension51% (36%-66%)69% (53%-85%)
      Vibration deficitReduced vibratory sense (128-Hz tuning fork)53% (38%-68%)81% (67%-95%)
      Pinprick deficitReduced pinprick sense (medial/lateral foot or calf)47% (32%-62%)81% (67%-95%)
      Impaired reflexAbsent Achilles tendon reflex46% (31%-61%)78% (64%-92%)
      a Data from Man Ther,
      • Laslett M.
      • Aprill C.N.
      • McDonald B.
      • Young S.B.
      Diagnosis of sacroiliac joint pain: validity of individual provocation tests and composites of tests.
      Arch Phys Med Rehabil,
      • van der Wurff P.
      • Buijs E.J.
      • Groen G.J.
      A multitest regimen of pain provocation tests as an aid to reduce unnecessary minimally invasive sacroiliac joint procedures.
      and J Pain.
      • Szadek K.M.
      • van der Wurff P.
      • van Tulder M.W.
      • Zuurmond W.W.
      • Perez R.S.
      Diagnostic validity of criteria for sacroiliac joint pain: a systematic review.
      b Data from J Neurol
      • Vroomen P.C.
      • de Krom M.C.
      • Knottnerus J.A.
      Diagnostic value of history and physical examination in patients suspected of sciatica due to disc herniation: a systematic review.
      and Cochrane Database Syst Rev.
      • van der Windt D.A.
      • Simons E.
      • Riphagen II,
      • et al.
      Physical examination for lumbar radiculopathy due to disc herniation in patients with low-back pain.
      c Data from Arthritis Rheum.
      • Gardner A.
      • Gardner E.
      • Morley T.
      Cauda equina syndrome: a review of the current clinical and medico-legal position.
      Axial LBP related to the paraspinal muscle or ligament strain is often precipitated by both strenuous and nonstrenuous activities including heavy lifting, repetitive movements, spinal torsion, or trauma. The onset of pain is generally delayed by 1 to 2 days and is often localized to the lumbosacral region. On physical examination, hypomobility due to muscle spasm or guarding may be evident, and pain may be reproduced with palpation of the paraspinal musculature. Although any muscle or ligament can potentially be affected, frequently involved structures include the multifidus, quadratus lumborum, erector spinae, and psoas muscles, as well as interspinous and supraspinous ligaments.
      • Vora A.J.
      • Doerr K.D.
      • Wolfer L.R.
      Functional anatomy and pathophysiology of axial low back pain: disc, posterior elements, sacroiliac joint, and associated pain generators.
      Myofascial pain may be an important contributing factor to other sources of LBP or a primary cause by itself and is characterized by the presence of trigger points that are hyperirritable tense bands of skeletal muscles.
      • Malanga G.A.
      • Cruz Colon E.J.
      Myofascial low back pain: a review.
      Patients will typically present with a history of localized or regional pain, and the range of motion may be reduced in the affected muscles. On physical examination, palpation of a trigger point will typically provoke sharp localized pain that may be referred to a contiguous body region, although this can be difficult, if not impossible to discern, in nonsuperficial muscles.
      • Malanga G.A.
      • Cruz Colon E.J.
      Myofascial low back pain: a review.
      A source of axial LBP often seen in children, adolescents, and young adults is bilateral stress fractures of the pars interarticularis (Figure 3), otherwise termed spondylolysis or a pars defect, which can lead to the development of spondylolisthesis. The incidence of lumbar spondylolysis ranges from 6% to 8%, and 95% of the occurrences involve the L5 vertebra.
      • Leone A.
      • Cianfoni A.
      • Cerase A.
      • Magarelli N.
      • Bonomo L.
      Lumbar spondylolysis: a review.
      Patients will typically present with axial LBP, with or without a radicular component, that is worsened by activities involving repetitive flexion-extension movements of the lumbar spine. Although conservative treatment is generally sufficient, surgery may be required to prevent the progression of spondylolisthesis.
      • Leone A.
      • Cianfoni A.
      • Cerase A.
      • Magarelli N.
      • Bonomo L.
      Lumbar spondylolysis: a review.

      Radicular Pain

      Herniated Intervertebral Disc

      Similar to axial LBP, the differential diagnosis of radicular pain is broad, but approximately 90% of cases in the nonelderly are caused by a herniated intervertebral disc at the L4-L5 or L5-S1 level.
      • Bartleson J.
      • Deen G.H.
      Spine Disorders: Medical and Surgical Management.
      • Koes B.W.
      • van Tulder M.W.
      • Peul W.C.
      Diagnosis and treatment of sciatica.
      Another important source of radicular pain includes foraminal stenosis, which is common because of far lateral disc herniation or facet joint hypertrophy. An inciting event may or may not be identified, but some patients report experiencing a “pop” in the region of the lumbar spine followed by the gradual onset of pain over the next 1 to 2 days. However, the single most important historical factor is the distribution of pain, which should follow a dermatomal pattern,
      • Czyrny J.J.
      • Lawrence J.
      The importance of paraspinal muscle EMG in cervical and lumbosacral radiculopathy: review of 100 cases.
      though approximately one-third of people have multiple affected dermatomes (Table 3).
      • Vroomen P.C.
      • de Krom M.C.
      • Knottnerus J.A.
      Diagnostic value of history and physical examination in patients suspected of sciatica due to disc herniation: a systematic review.
      In contrast to nociceptive pain, neuropathic LBP is often described as a sharp, lancinating, or burning sensation. Patients may report that pain is worsened by forward bending, coughing, sneezing, or prolonged sitting and improved with recumbency. When localizing the affected nerve root on the basis of the dermatomal distribution of pain, it is important to recognize that each nerve root exits the spinal column beneath the pedicle of the vertebral body with the same number as the nerve. For instance, the L4 nerve root exits beneath the pedicle of the L4 vertebral body, which is situated above the interspinal disc at this level. Therefore, disruption of the disc situated between the L4 and L5 vertebrae will typically impinge the traversing L5 nerve root (unless it is a far lateral herniation that accounts for <10% of cases), but not the L4 nerve root. On physical examination, the specificities of various physical tests and neurological findings for detecting lumbar radiculopathy are good, but the sensitivities are generally low (Table 2).
      • Vroomen P.C.
      • de Krom M.C.
      • Knottnerus J.A.
      Diagnostic value of history and physical examination in patients suspected of sciatica due to disc herniation: a systematic review.
      • van der Windt D.A.
      • Simons E.
      • Riphagen II,
      • et al.
      Physical examination for lumbar radiculopathy due to disc herniation in patients with low-back pain.
      Table 3Sensory, Motor, and Reflex Abnormalities Associated With Lumbar Spine Radiculopathy
      Adapted from Bartleson et al
      • Bartleson J.
      • Deen G.H.
      Spine Disorders: Medical and Surgical Management.
      with permission.
      RootRegion of painDermatomal sensory distributionMotorReflex
      L1InguinalInguinalNoneCremasteric
      L2Inguinal

      Anterior thigh
      Proximal anterior and medial thighHip flexion

      Hip adduction

      Some knee extension
      Cremasteric

      Thigh adductor
      L3Anterior thigh and kneeAnterior and medial thighKnee extension

      Hip flexion

      Hip adduction
      Patellar (knee)

      Thigh adductor
      L4Anterior thigh and anteromedial legAnterior knee and medial legHip extension

      Hip flexion

      Hip adduction
      Patellar
      L5Posterolateral thigh

      Lateral leg

      Medial foot
      Anterolateral leg

      Dorsal aspect foot

      Great toe
      Foot dorsiflexion

      Knee flexion

      Hip abduction

      Toe extension/flexion
      Possibly internal

      Hamstring
      S1Posterior thigh/leg

      Heel

      Lateral foot
      Posterolateral leg

      Heel

      Lateral Foot
      Plantar flexion

      Toe flexion

      Knee flexion

      Hip extension
      Achilles (ankle)
      One potentially devastating source of LBP is cauda equina syndrome, which is caused by severe compression of the cauda equina due to massive midline disk herniation, tumor, or epidural abscess.
      • Gardner A.
      • Gardner E.
      • Morley T.
      Cauda equina syndrome: a review of the current clinical and medico-legal position.
      Cauda equina syndrome is a surgical emergency characterized by the sudden onset of axial or radicular pain, leg weakness, bowel and/or bladder dysfunction, and loss of perineal sensation, which is also referred to as saddle anesthesia.

      Lumbar Spinal Stenosis

      Lumbar spinal stenosis can be associated with both axial and radicular pain, but the hallmark symptom is neurogenic claudication, which has a sensitivity and specificity of 88% (95% CI, 78%-98%) and 34% (95% CI, 18%-50%), respectively.
      • Katz J.N.
      • Dalgas M.
      • Stucki G.
      • et al.
      Degenerative lumbar spinal stenosis. Diagnostic value of the history and physical examination.
      Patients with neurogenic claudication will typically report the onset or worsening of radicular pain when standing and walking (sensitivity, 71%; specificity, 30%), and rapid improvement in pain with sitting (sensitivity, 52%; specificity, 83%).
      • Katz J.N.
      • Dalgas M.
      • Stucki G.
      • et al.
      Degenerative lumbar spinal stenosis. Diagnostic value of the history and physical examination.
      • Suri P.
      • Rainville J.
      • Kalichman L.
      • Katz J.N.
      Does this older adult with lower extremity pain have the clinical syndrome of lumbar spinal stenosis?.
      Pain will often radiate into the buttocks, thighs, and/or legs in the distribution of 1 or more dermatomes. Although the mechanism of neurogenic claudication has not been fully elucidated, the prevailing evidence suggests that activities associated with lumbar extension, which reduces the cross-sectional area of the spinal canal, leads to mechanical compression and subsequent impairment of the nerve.
      • Kobayashi S.
      Pathophysiology, diagnosis and treatment of intermittent claudication in patients with lumbar canal stenosis.
      This proposed mechanism partly explains the reversibility of symptoms with lumbar flexion, which increases the cross-sectional area of the spinal canal and neural foramina.
      • Katz J.N.
      • Harris M.B.
      Clinical practice: lumbar spinal stenosis.
      Other important historical factors associated with a diagnosis of lumbar spinal stenosis include age greater than 65 years (sensitivity, 77%; specificity, 69%) and the presence of bilateral buttock or leg pain (sensitivity, 88%; specificity, 34%).
      • Katz J.N.
      • Dalgas M.
      • Stucki G.
      • et al.
      Degenerative lumbar spinal stenosis. Diagnostic value of the history and physical examination.
      • Suri P.
      • Rainville J.
      • Kalichman L.
      • Katz J.N.
      Does this older adult with lower extremity pain have the clinical syndrome of lumbar spinal stenosis?.
      On physical examination, the accuracy of motor or sensory findings is generally reliable, and most likely reflect the involvement of the proprioceptive fibers in the posterior columns of the spinal cord (Table 2).
      • Katz J.N.
      • Dalgas M.
      • Stucki G.
      • et al.
      Degenerative lumbar spinal stenosis. Diagnostic value of the history and physical examination.
      • Katz J.N.
      • Harris M.B.
      Clinical practice: lumbar spinal stenosis.
      Other important considerations in the differential diagnosis of lumbar spinal stenosis include hip osteoarthritis, trochanteric bursitis, and vascular claudication. Vascular claudication can be distinguished from neurogenic claudication by signs of poor perfusion, including diminished pedal pulses, pallor, and decreased temperature in the feet. One study
      • Nadeau M.
      • Rosas-Arellano M.P.
      • Gurr K.R.
      • et al.
      The reliability of differentiating neurogenic claudication from vascular claudication based on symptomatic presentation.
      found that a positive “shopping cart sign” (relief of pain when leaning forward as if pushing a shopping cart) and pain that was triggered by standing alone and relieved by sitting were the most reliable means to differentiate neurogenic from vascular claudication.

      Diagnostic Testing

      Diagnostic Imaging

      Despite the availability of practice guidelines for more than 20 years,
      • Bigos S.
      • Bowyer O.
      • Braen G.
      • et al.
      Acute Low Back Problems in Adults.
      overuse of imaging persists. This is important because imaging has long been recognized as a key contributor to the overall costs of LBP,
      • Deyo R.A.
      Cascade effects of medical technology.
      and early imaging has not been shown to improve outcomes of patients with axial or radicular pain.
      • Chou R.
      • Fu R.
      • Carrino J.A.
      • Deyo R.A.
      Imaging strategies for low-back pain: systematic review and meta-analysis.
      • Jarvik J.G.
      • Gold L.S.
      • Comstock B.A.
      • et al.
      Association of early imaging for back pain with clinical outcomes in older adults.
      • Cohen S.P.
      • Gupta A.
      • Strassels S.A.
      • et al.
      Effect of MRI on treatment results or decision making in patients with lumbosacral radiculopathy referred for epidural steroid injections: a multicenter, randomized controlled trial.
      In addition, imaging abnormalities not directly related to the patients' symptoms may lead to extraneous testing, contribute to more aggressive treatments, and diminish patients' health perception.
      • Graves J.M.
      • Fulton-Kehoe D.
      • Jarvik J.G.
      • Franklin G.M.
      Health care utilization and costs associated with adherence to clinical practice guidelines for early magnetic resonance imaging among workers with acute occupational low back pain.
      • Ash L.M.
      • Modic M.T.
      • Obuchowski N.A.
      • Ross J.S.
      • Brant-Zawadzki M.N.
      • Grooff P.N.
      Effects of diagnostic information, per se, on patient outcomes in acute radiculopathy and low back pain.
      Best practice guidelines for diagnostic imaging for LBP have been published by the American College of Physicians (Table 4).
      • Chou R.
      • Qaseem A.
      • Owens D.K.
      • Shekelle P.
      Clinical Guidelines Committee of the American College of Physicians
      Diagnostic imaging for low back pain: advice for high-value health care from the American College of Physicians.
      The timing and indications for obtaining imaging studies in these guidelines are risk-stratified and center around the temporal course of the patients' symptoms, which allow these recommendations to be readily implemented in daily clinical practice.
      Table 4American College of Physicians Guideline for Imaging in Patients With Low Back Pain
      ESR = erythrocyte sedimentation rate; MRI = magnetic resonance imaging.
      ,
      Data from Ann Intern Med.105
      Clinical actionImaging modalityIndications for initial imaging
      Immediate imagingRadiograph and ESRMajor risk factors for cancer
      MRISuspect spinal infection
      Signs of cauda equina syndrome
      Severe neurological deficits
      Defer imaging until after initial treatmentRadiograph and/or ESRWeaker risk factors for cancer
      Risk factors for inflammatory arthritides
      Risk factors for vertebral compression fracture
      MRISigns of radiculopathy
      Signs of spinal stenosis
      No imagingImproved/resolved pain 1 mo after treatment
      Previous imaging with no change in clinical status
      a ESR = erythrocyte sedimentation rate; MRI = magnetic resonance imaging.
      b Data from Ann Intern Med.
      • Chou R.
      • Qaseem A.
      • Owens D.K.
      • Shekelle P.
      Clinical Guidelines Committee of the American College of Physicians
      Diagnostic imaging for low back pain: advice for high-value health care from the American College of Physicians.

      Electrodiagnostics

      Electromyography and nerve conduction studies are the principal electrodiagnostic tests used in the evaluation of patients with radicular pain and lumbar spinal stenosis. In general, the primary objectives of electrodiagnostics for radicular pain are 2-fold.
      • Sandoval A.E.
      Electrodiagnostics for low back pain.
      First, if indicated, electrodiagnostic tests are useful to confirm the existence of radiculopathy and to exclude the presence of other peripheral nerve disorders (eg, mononeuropathy multiplex and plexopathy).
      • Sandoval A.E.
      Electrodiagnostics for low back pain.
      Second, electrodiagnostic testing can help clarify which nerve root levels are involved, determine the type of nerve root dysfunction (eg, demyelination, axonal loss, and presence of conduction block), and provide information on the severity and chronicity of nerve root abnormalities.
      • Sandoval A.E.
      Electrodiagnostics for low back pain.
      Electrodiagnostics can complement the findings of diagnostic imaging studies
      • Haig A.J.
      • Geisser M.E.
      • Tong H.C.
      • et al.
      Electromyographic and magnetic resonance imaging to predict lumbar stenosis, low-back pain, and no back symptoms.
      • Reza Soltani Z.
      • Sajadi S.
      • Tavana B.
      A comparison of magnetic resonance imaging with electrodiagnostic findings in the evaluation of clinical radiculopathy: a cross-sectional study.
      and are particularly useful in the following 2 clinical scenarios: (1) physical examination does not correlate with imaging studies and (2) to clarify the functional significance of an imaging abnormality.
      • Sandoval A.E.
      Electrodiagnostics for low back pain.
      Previous studies
      • Plastaras C.T.
      • Joshi A.B.
      The electrodiagnostic evaluation of radiculopathy.
      • Mondelli M.
      • Aretini A.
      • Arrigucci U.
      • Ginanneschi F.
      • Greco G.
      • Sicurelli F.
      Clinical findings and electrodiagnostic testing in 108 consecutive cases of lumbosacral radiculopathy due to herniated disc.
      have found a sensitivity ranging between 40% and 85% in detecting lumbosacral radiculopathy, depending on the reference standard. However, electrodiagnostic tests are time-sensitive because nerve root abnormalities may not be reliably detectable until 3 weeks after the onset of symptoms.
      • Sandoval A.E.
      Electrodiagnostics for low back pain.
      • Plastaras C.T.
      Electrodiagnostic challenges in the evaluation of lumbar spinal stenosis.

      Diagnostic Injections

      Diagnostic injections are often used to confirm a putative diagnosis and to identify patients who may be candidates for further interventional treatments. For example, blocks targeting nerves innervating the lumbar facet joints (eg, medial branch blocks) and sacroiliac joints (eg, both intra- and extra-articular blocks) help distinguish patients with axial LBP who may be candidates for percutaneous radiofrequency denervation procedures.
      • Cohen S.P.
      • Hurley R.W.
      • Buckenmaier III, C.C.
      • Kurihara C.
      • Morlando B.
      • Dragovich A.
      Randomized placebo-controlled study evaluating lateral branch radiofrequency denervation for sacroiliac joint pain.
      • Cohen S.P.
      • Williams K.A.
      • Kurihara C.
      • et al.
      Multicenter, randomized, comparative cost-effectiveness study comparing 0, 1, and 2 diagnostic medial branch (facet joint nerve) block treatment paradigms before lumbar facet radiofrequency denervation.
      Provocative discography is often touted as the only means to establish a relationship between disc pathology and symptoms but is characterized by a high false-positive rate in some patients (eg, those with psychopathology and previous surgery).
      • Provenzano D.A.
      Diagnostic discography: what is the clinical utility?.
      Furthermore, the evidence that discography may improve surgical outcomes is limited to a recent subgroup analysis of a randomized study
      • Margetic P.
      • Pavic R.
      • Stancic M.F.
      Provocative discography screening improves surgical outcome.
      comparing fusion outcomes in those patients who underwent presurgical discography screening and those who did not. In patients with radicular pain, selective nerve root blocks can be considered when imaging, physical examination, or electrodiagnostic studies are inconsistent or noncorroborative.
      • Yeom J.S.
      • Lee J.W.
      • Park K.W.
      • et al.
      Value of diagnostic lumbar selective nerve root block: a prospective controlled study.
      Patients should be referred to a pain medicine specialist with expertise in performing and interpreting the outcomes of diagnostic injections.

      Treatment of LBP

      Pharmacological Treatment

      There are multiple trials evaluating a plethora of medication classes for LBP, but aside from studies conducted in patients with radiculopathy, most have been performed in patients with axial LBP. There is strong evidence in support of nonsteroidal anti-inflammatory drugs for chronic LBP compared with placebo for up to 3 months, but long-term outcome studies are lacking.
      • Kuijpers T.
      • van Middelkoop M.
      • Rubinstein S.M.
      • et al.
      A systematic review on the effectiveness of pharmacological interventions for chronic non-specific low-back pain.
      Muscle relaxants are more effective than placebo for nonspecific LBP, with stronger evidence supporting their use for acute rather than chronic pain. However, caution should be exercised when prescribing drugs such as carisoprodol and benzodiazepines, which carry greater risks (eg, physical dependence) but no greater efficacy than do other muscle relaxants.
      • van Tulder M.W.
      • Touray T.
      • Furlan A.D.
      • Solway S.
      • Bouter L.M.
      Cochrane Back Review Group
      Muscle relaxants for nonspecific low back pain: a systematic review within the framework of the Cochrane collaboration.
      For antidepressants, the results of systematic reviews are mixed. One narrative review
      • Williamson O.D.
      • Sagman D.
      • Bruins R.H.
      • Boulay L.J.
      • Schacht A.
      Antidepressants in the treatment for chronic low back pain: questioning the validity of meta-analyses.
      found that 3 of 5 systematic reviews evaluating 14 randomized trials found some evidence of benefit. In general, tricyclic antidepressants have been found to have superior efficacy than serotonin-norepinephrine reuptake inhibitors, which, in turn, are more efficacious than serotonin-specific reuptake inhibitors.
      • Finnerup N.B.
      • Sindrup S.H.
      • Jensen T.S.
      The evidence for pharmacological treatment of neuropathic pain.
      Opioids, including tramadol and tapentadol, have been shown to be effective for episodes of acute LBP, as well as for chronic LBP unresponsive to more conservative treatment.
      • Lasko B.
      • Levitt R.J.
      • Rainsford K.D.
      • Bouchard S.
      • Rozova A.
      • Robertson S.
      Extended-release tramadol/paracetamol in moderate-to-severe pain: a randomized, placebo-controlled study in patients with acute low back pain.
      • Biondi D.
      • Xiang J.
      • Benson C.
      • Etropolski M.
      • Moskovitz B.
      • Rauschkolb C.
      Tapentadol immediate release versus oxycodone immediate release for treatment of acute low back pain.
      However, the long-term benefits of opioids, or superiority over nonopioid analgesic medications, remain unproven. For instance, in a systemic review, Chaparro et al
      • Chaparro L.E.
      • Furlan A.D.
      • Deshpande A.
      • Mailis-Gagnon A.
      • Atlas S.
      • Turk D.C.
      Opioids compared to placebo or other treatments for chronic low-back pain.
      found low- to moderate-quality evidence for the short-term benefits of opioids as compared with placebo. For pain relief and functional improvement, no evidence was found to suggest that opioids were superior to nonsteroidal anti-inflammatory drugs or antidepressants.
      • Chaparro L.E.
      • Furlan A.D.
      • Deshpande A.
      • Mailis-Gagnon A.
      • Atlas S.
      • Turk D.C.
      Opioids compared to placebo or other treatments for chronic low-back pain.
      Few well-designed clinical trials exist for adjuvant medication treatment of radicular pain. Gabapentinoids have shown mixed results in randomized controlled trials as stand-alone and add-on analgesic medications, with a large, placebo-controlled, industry-sponsored study
      • Baron R.
      • Freynhagen R.
      • Tölle T.R.
      • et al.
      A0081007 Investigators
      The efficacy and safety of pregabalin in the treatment of neuropathic pain associated with chronic lumbosacral radiculopathy.
      failing to show efficacy for pregabalin. An unpublished industry-sponsored study
      • Zhou M.
      • Chen N.
      • He L.
      • Yang M.
      • Zhu C.
      • Wu F.
      Oxcarbazepine for neuropathic pain.
      found no efficacy for oxcarbazepine in 145 patients with lumbosacral radiculopathy. However, 2 placebo-controlled crossover studies
      • Khoromi S.
      • Patsalides A.
      • Parada S.
      • Salehi V.
      • Meegan J.M.
      • Max M.B.
      Topiramate in chronic lumbar radicular pain.
      • O'Connor A.B.
      • Dworkin R.H.
      Treatment of neuropathic pain: an overview of recent guidelines.
      found efficacy for topiramate, a medication not classified as a first- or second-line treatment of neuropathic pain. In a double-blind, placebo-controlled, crossover study
      • Khoromi S.
      • Cui L.
      • Nackers L.
      • Max M.B.
      Morphine, nortriptyline and their combination vs. placebo in patients with chronic lumbar root pain.
      comparing nortriptyline, sustained-release morphine, and the combination of nortriptyline and morphine to an active placebo, small reductions in pain for all treatment groups were observed, and more than half of patients reported adverse effects. A more recent meta-analysis found that the efficacy for duloxetine in patients with chronic LBP was similar to other medications including nonsteroidal anti-inflammatory drugs, opioids, selective serotonin reuptake inhibitors, and glucosamine.
      • Cawston H.
      • Davie A.
      • Paget M.A.
      • Skljarevski V.
      • Happich M.
      Efficacy of duloxetine versus alternative oral therapies: an indirect comparison of randomised clinical trials in chronic low back pain.
      Recently, evidence has emerged in support of a possible infectious etiology for some cases of LBP.
      • Urquhart D.M.
      • Zheng Y.
      • Cheng A.C.
      • et al.
      Could low grade bacterial infection contribute to low back pain? A systematic review.
      A double-blind placebo-controlled study
      • Albert H.B.
      • Sorensen J.S.
      • Christensen B.S.
      • Manniche C.
      Antibiotic treatment in patients with chronic low back pain and vertebral bone edema (Modic type 1 changes): a double-blind randomized clinical controlled trial of efficacy.
      performed in 162 patients with chronic LBP and endplate signal changes indicative of edema (Modic type 1) after a recent (<24 months) disc herniation found significant reductions in both back and leg pain in those treated with oral antibiotics for 100 days. The rationale behind antibiotic treatment is that tears in the outer fibers of annulus fibrosus may enable anaerobic bacteria to enter the disc, resulting in a low-grade inflammatory process
      • Albert H.B.
      • Kjaer P.
      • Jensen T.S.
      • Sorensen J.S.
      • Bendix T.
      • Manniche C.
      Modic changes, possible causes and relation to low back pain.
      ; however, these findings are yet to be replicated.

      Therapeutic Injections and Fluoroscopically Guided Procedures

      The use of injections and other minimally invasive interventions for LBP has risen dramatically over the past decade, but increased use has not been accompanied by a concomitant reduction in disability rates or surgical procedures.
      • Manchikanti L.
      • Falco F.J.
      • Singh V.
      • et al.
      Utilization of interventional techniques in managing chronic pain in the Medicare population: analysis of growth patterns from 2000 to 2011.
      • Deyo R.A.
      • Mirza S.K.
      • Turner J.A.
      • Martin B.I.
      Overtreating chronic back pain: time to back off?.
      If therapeutic injections are considered to be a treatment option, the patient should be referred to a pain medicine specialist with expertise in performing image-guided injections. Fluoroscopically guided corticosteroid injections targeting the facet joints have not been shown to provide significant benefits in controlled trials, whereas intra- and extra-articular sacroiliac joint injections have been shown to provide only short-term benefits.
      • Cohen S.P.
      • Raja S.N.
      Pathogenesis, diagnosis, and treatment of lumbar zygapophysial (facet) joint pain.
      • Hansen H.
      • Manchikanti L.
      • Simopoulos T.T.
      • et al.
      A systematic evaluation of the therapeutic effectiveness of sacroiliac joint interventions.
      However, after the appropriate diagnostic blocks, various radiofrequency denervation (ie, nerve ablation) procedures have been associated with sustained pain relief in carefully selected patients with facet and sacroiliac joint pain.
      • Cohen S.P.
      • Raja S.N.
      Pathogenesis, diagnosis, and treatment of lumbar zygapophysial (facet) joint pain.
      • Cohen S.P.
      • Chen Y.
      • Neufeld N.J.
      Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment.
      • Hansen H.
      • Manchikanti L.
      • Simopoulos T.T.
      • et al.
      A systematic evaluation of the therapeutic effectiveness of sacroiliac joint interventions.
      Interventional treatments of discogenic axial LBP have been largely disappointing. Placebo-controlled studies evaluating intradiscal steroids
      • Khot A.
      • Bowditch M.
      • Powell J.
      • Sharp D.
      The use of intradiscal steroid therapy for lumbar spinal discogenic pain: a randomized controlled trial.
      • Simmons J.W.
      • McMillin J.N.
      • Emery S.F.
      • Kimmich S.J.
      Intradiscal steroids: a prospective double-blind clinical trial.
      and cytokine inhibitors
      • Cohen S.P.
      • Wenzell D.
      • Hurley R.W.
      • et al.
      A double-blind, placebo-controlled, dose-response pilot study evaluating intradiscal etanercept in patients with chronic discogenic low back pain or lumbosacral radiculopathy.
      have yielded negative results. Although an initial placebo-controlled study
      • Peng B.
      • Pang X.
      • Wu Y.
      • Zhao C.
      • Song X.
      A randomized placebo-controlled trial of intradiscal methylene blue injection for the treatment of chronic discogenic low back pain.
      evaluating intradiscal methylene blue injection found more than a 90% success rate at 2-year follow-up, the lack of supporting preclinical evidence and the failure to replicate these results in subsequent uncontrolled studies
      • Gupta G.
      • Radhakrishna M.
      • Chankowsky J.
      • Asenjo J.F.
      Methylene blue in the treatment of discogenic low back pain.
      • Kim S.H.
      • Ahn S.H.
      • Cho Y.W.
      • Lee D.G.
      Effect of intradiscal methylene blue injection for the chronic discogenic low back pain: one year prospective follow-up study.
      has led to the virtual abandonment of this treatment. Several techniques have been developed to treat discogenic LBP by heating intradiscal elements. Although an early controlled study
      • Pauza K.J.
      • Howell S.
      • Dreyfuss P.
      • Peloza J.H.
      • Dawson K.
      • Bogduk N.
      A randomized, placebo-controlled trial of intradiscal electrothermal therapy for the treatment of discogenic low back pain.
      suggested that some patients may benefit from intradiscal electrothermal therapy, a treatment that purportedly acts by coagulating pain receptors, altering collagen architecture in the disc, and sealing annular tears, subsequent studies either failed to replicate these results
      • Freeman B.J.
      • Fraser R.D.
      • Cain C.M.
      • Hall D.J.
      • Chapple D.C.
      A randomized, double-blind, controlled trial: intradiscal electrothermal therapy versus placebo for the treatment of chronic discogenic low back pain.
      • Kvarstein G.
      • Måwe L.
      • Indahl A.
      • et al.
      A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy—a 12-month follow-up.
      or found that any benefit tended to be short-lived.
      • Freedman B.A.
      • Cohen S.P.
      • Kuklo T.R.
      • Lehman R.A.
      • Larkin P.
      • Giuliani J.R.
      Intradiscal electrothermal therapy (IDET) for chronic low back pain in active-duty soldiers: 2-year follow-up.
      More recently, a similar procedure known as biacuplasty has emerged that circumvents some of the technical problems associated with performing intradiscal electrothermal therapy. A single randomized trial
      • Kapural L.
      • Vrooman B.
      • Sarwar S.
      • et al.
      Radiofrequency intradiscal biacuplasty for treatment of discogenic lower back pain: a 12-month follow-up.
      found that patients who underwent biacuplasty obtained better pain relief and functional improvement than did a control group who underwent sham lesioning, with the results persisting through 1-year follow-up. However, concerns about long-term effectiveness and the propensity for disc injury after annulus puncture limit the use of this treatment.
      The effects of local anesthetic, steroid, or botulinum toxin injections for muscle-related axial LBP are mixed, and the findings of 2 systematic reviews suggest that these treatments provide only limited short-term pain relief.
      • Waseem Z.
      • Boulias C.
      • Gordon A.
      • Ismail F.
      • Sheean G.
      • Furlan A.D.
      Botulinum toxin injections for low-back pain and sciatica.
      • Staal J.B.
      • de Bie R.A.
      • de Vet H.C.
      • Hildebrandt J.
      • Nelemans P.
      Injection therapy for subacute and chronic low back pain: an updated Cochrane review.
      Epidural steroid injections (ESIs) are the most frequently performed pain management procedures for radicular pain. In well-selected patients, ESIs appear to provide significant benefit as compared with sham injections and conservative treatment for approximately 6 weeks, though some patients may obtain longer benefit.
      • Cohen S.P.
      • Bicket M.C.
      • Jamison D.
      • Wilkinson I.
      • Rathmell J.P.
      Epidural steroids: a comprehensive, evidence-based review.
      Similar to other treatments, patients with greater disease burden, receiving opioid therapy, and with coexisting psychosocial dysfunction are less likely to respond to ESIs.
      • Jamison R.N.
      • VadeBoncouer T.
      • Ferrante F.M.
      Low back pain patients unresponsive to an epidural steroid injection: identifying predictive factors.
      • Hopwood M.B.
      • Abram S.E.
      Factors associated with failure of lumbar epidural steroids.
      • Kirpalani D.
      • Mitra R.
      Is chronic opioid use a negative predictive factor for response to cervical epidural steroid injections?.
      A recent systematic review
      • Bicket M.C.
      • Horowitz J.M.
      • Benzon H.T.
      • Cohen S.P.
      Epidural injections in prevention of surgery for spinal pain: systematic review and meta-analysis of randomized controlled trials.
      found that ESIs may possibly reduce the need for surgery in the short-term, but the evidence for long-term surgery prevention is mostly anecdotal and based on indirect evidence or small clinical trials.
      • Riew K.D.
      • Park J.B.
      • Cho Y.S.
      • et al.
      Nerve root blocks in the treatment of lumbar radicular pain: a minimum five-year follow-up.
      Technical factors that may improve ESI treatment results include the use of transforaminal rather than interlaminar injections and the use of depo-steroids.
      • Cohen S.P.
      • Bicket M.C.
      • Jamison D.
      • Wilkinson I.
      • Rathmell J.P.
      Epidural steroids: a comprehensive, evidence-based review.
      However, the administration of transforaminal depo-steroids may be associated with rare but catastrophic consequences including spinal cord infarction.
      • Atluri S.
      • Glaser S.E.
      • Shah R.V.
      • Sudarshan G.
      Needle position analysis in cases of paralysis from transforaminal epidurals: consider alternative approaches to traditional technique.
      This has led researchers to investigate alternatives to ESI. One such alternative that has garnered intense interest is the use of inflammatory cytokine inhibitors such as the tumor necrosis factor antagonist etanercept. Yet, to date, clinical trials
      • Cohen S.P.
      • White R.L.
      • Kurihara C.
      • et al.
      Epidural steroids, etanercept, or saline in subacute sciatica: a multicenter, randomized trial.
      • Ohtori S.
      • Miyagi M.
      • Eguchi Y.
      • et al.
      Epidural administration of spinal nerves with the tumor necrosis factor-alpha inhibitor, etanercept, compared with dexamethasone for treatment of sciatica in patients with lumbar spinal stenosis: a prospective randomized study.
      • Freeman B.J.
      • Ludbrook G.L.
      • Hall S.
      • et al.
      Randomized, double-blind, placebo-controlled, trial of transforaminal epidural etanercept for the treatment of symptomatic lumbar disc herniation.
      evaluating epidural etanercept have yielded conflicting results.

      Physical Modalities and Psychological Treatments

      An extensive array of physical modalities and behavioral treatments are used for axial and radicular pain. Some of the more widely used physical modalities associated with improvements in pain and functioning include exercise,

      Searle A, Spink M, Ho A, Chuter V. Exercise interventions for the treatment of chronic low back pain: a systematic review and meta-analysis of randomised controlled trials [published online ahead of print February 13, 2015]. Clin Rehabil. doi:10.1177/0269215515570379.

      specifically walking,

      Lawford BJ, Walters J, Ferrar K. Does walking improve disability status, function, or quality of life in adults with chronic low back pain? A systematic review [published online ahead of print June 18, 2015]. Clin Rehabil. doi:10.1177/0269215515590487.

      yoga,
      • Cramer H.
      • Lauche R.
      • Haller H.
      • Dobos G.
      A systematic review and meta-analysis of yoga for low back pain.
      and Pilates.
      • Wells C.
      • Kolt G.S.
      • Marshall P.
      • Hill B.
      • Bialocerkowski A.
      The effectiveness of Pilates exercise in people with chronic low back pain: a systematic review.
      When exercise is recommended, patients may be more likely to participate in programs that reflect their individual preferences, previous exercise experiences, and fitness level.
      • Slade S.C.
      • Patel S.
      • Underwood M.
      • Keating J.L.
      What are patient beliefs and perceptions about exercise for nonspecific chronic low back pain? A systematic review of qualitative studies.
      Other forms of treatment associated with favorable outcomes include massage,
      • Furlan A.D.
      • Imamura M.
      • Dryden T.
      • Irvin E.
      Massage for low back pain: an updated systematic review within the framework of the Cochrane Back Review Group.
      acupuncture,
      • Lam M.
      • Galvin R.
      • Curry P.
      Effectiveness of acupuncture for nonspecific chronic low back pain: a systematic review and meta-analysis.
      therapeutic ultrasound,
      • Ebadi S.
      • Henschke N.
      • Nakhostin Ansari N.
      • Fallah E.
      • van Tulder M.W.
      Therapeutic ultrasound for chronic low-back pain.
      and manipulative spinal therapies,
      • Franke H.
      • Franke J.D.
      • Fryer G.
      Osteopathic manipulative treatment for nonspecific low back pain: a systematic review and meta-analysis.
      • Franke H.
      • Fryer G.
      • Ostelo R.W.
      • Kamper S.J.
      Muscle energy technique for non-specific low-back pain.
      and there is some evidence that supports the integration of these treatments into conventional medical therapy for LBP.
      • Kizhakkeveettil A.
      • Rose K.
      • Kadar G.E.
      Integrative therapies for low back pain that include complementary and alternative medicine care: a systematic review.
      Although these treatments appear to provide short-term benefit compared with no treatment, the evidence supporting the superiority over sham therapy, other treatments, or long-term benefit is at best mixed.
      • Rubinstein S.M.
      • van Middelkoop M.
      • Kuijpers T.
      • et al.
      A systematic review on the effectiveness of complementary and alternative medicine for chronic non-specific low-back pain.
      Transcutaneous electrical nerve stimulation is widely used in clinical practice, but current evidence does not support its use for LBP.
      • Khadilkar A.
      • Odebiyi D.O.
      • Brosseau L.
      • Wells G.A.
      Transcutaneous electrical nerve stimulation (TENS) versus placebo for chronic low-back pain.
      • Dubinsky R.M.
      • Miyasaki J.
      Assessment: efficacy of transcutaneous electric nerve stimulation in the treatment of pain in neurologic disorders (an evidence-based review): report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology.
      Chronic LBP can have devastating effects on emotional functioning and sense of well-being.
      • Snelgrove S.
      • Liossi C.
      Living with chronic low back pain: a metasynthesis of qualitative research.
      One of the most widely used psychological treatments of chronic LBP is cognitive behavioral therapy, which focuses on examining the relationships between thoughts, feelings, and behaviors. This form of therapy is associated with improvements in overall emotional functioning and can be delivered in individual or group sessions or as part of a more comprehensive multidisciplinary biopsychosocial rehabilitation program.
      • Kamper S.J.
      • Apeldoorn A.T.
      • Chiarotto A.
      • et al.
      Multidisciplinary biopsychosocial rehabilitation for chronic low back pain.
      • Henschke N.
      • Ostelo R.W.
      • van Tulder M.W.
      • et al.
      Behavioural treatment for chronic low-back pain.
      Mindfulness-based stress reduction is a program that incorporates a combination of meditation, bodily awareness, and yoga-like movements. Recent evidence suggests that this form of treatment may lead to improvements in pain acceptance, but evidence supporting its effectiveness in improving pain intensity and physical functioning remains inconclusive.
      • Cramer H.
      • Haller H.
      • Lauche R.
      • Dobos G.
      Mindfulness-based stress reduction for low back pain: a systematic review.

      Lumbar Spine Surgery, Neurostimulation, and Intrathecal Drug Delivery

      A broad range of operative techniques are used to treat LBP, including spinal decompression, discectomy, foraminotomies, disc prosthesis (artificial disc replacement), minimally invasive and microsurgeries, and various approaches for spinal fusion with or without instrumentation. The indications for performing the various lumbar spine operations are complex and depend, in part, on individual patient factors, but geographic variations in surgical rates suggest that other factors, including access to health care resources, may influence the surgical decision-making process.
      • Pannell W.C.
      • Savin D.D.
      • Scott T.P.
      • Wang J.C.
      • Daubs M.D.
      Trends in the surgical treatment of lumbar spine disease in the United States.
      • Mroz T.E.
      • Lubelski D.
      • Williams S.K.
      • et al.
      Differences in the surgical treatment of recurrent lumbar disc herniation among spine surgeons in the United States.
      The general indications for commonly performed lumbar spine operations include spinal decompression for radicular symptoms including lumbar spinal stenosis as well as spinal fusion or disc prosthesis for discogenic LBP without nerve root involvement.
      In a systematic review
      • Jacobs W.C.
      • van Tulder M.
      • Arts M.
      • et al.
      Surgery versus conservative management of sciatica due to a lumbar herniated disc: a systematic review.
      that investigated the effects of spinal decompression compared with nonoperative management of radicular pain, early surgery within 12 weeks of the onset of radicular pain was associated with faster pain relief compared with prolonged conservative treatment. However, there was no significant group difference in pain or functionality at 1- and 2-year follow-up.
      • Jacobs W.C.
      • van Tulder M.
      • Arts M.
      • et al.
      Surgery versus conservative management of sciatica due to a lumbar herniated disc: a systematic review.
      In patients with lumbar spinal stenosis with or without spondylolisthesis, decompressive laminectomy was associated with improved pain, disability, and quality of life than was conservative treatment.
      • Kovacs F.M.
      • Urrútia G.
      • Alarcón J.D.
      Surgery versus conservative treatment for symptomatic lumbar spinal stenosis: a systematic review of randomized controlled trials.
      • Chou R.
      • Baisden J.
      • Carragee E.J.
      • Resnick D.K.
      • Shaffer W.O.
      • Loeser J.D.
      Surgery for low back pain: a review of the evidence for an American Pain Society Clinical Practice Guideline.
      The favorable benefits of surgical decompression emerged at 3 to 6 months and were still evident 2 to 4 years after surgery.
      • Kovacs F.M.
      • Urrútia G.
      • Alarcón J.D.
      Surgery versus conservative treatment for symptomatic lumbar spinal stenosis: a systematic review of randomized controlled trials.
      However, a recent systematic review
      • Machado G.C.
      • Ferreira P.H.
      • Harris I.A.
      • et al.
      Effectiveness of surgery for lumbar spinal stenosis: a systematic review and meta-analysis.
      found that decompression with fusion was not superior to decompression alone for lumbar spinal stenosis and concluded that the efficacy of various surgical treatments remains uncertain. For discogenic LBP, disability scores at 2- to 4-year follow-up were similar in patients randomized to undergo spinal fusion or cognitive behavioral-based pain rehabilitation.
      • Ibrahim T.
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      • Gabbar O.
      Surgical versus non-surgical treatment of chronic low back pain: a meta-analysis of randomised trials.
      • Mirza S.K.
      • Deyo R.A.
      Systematic review of randomized trials comparing lumbar fusion surgery to nonoperative care for treatment of chronic back pain.
      Although disc prosthesis is associated with more preserved range of motion than is spinal fusion and, in some contexts, may be superior to spinal fusion for improvements in pain and disability,
      • Wei J.
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      • Lv C.
      Comparison of artificial total disc replacement versus fusion for lumbar degenerative disc disease: a meta-analysis of randomized controlled trials.
      the outcomes compared to pain rehabilitation are mixed.
      • Hellum C.
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      • Storheim K.
      • et al.
      Surgery with disc prosthesis versus rehabilitation in patients with low back pain and degenerative disc: two year follow-up of randomised study.
      For example, in a randomized comparative trial,
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      • et al.
      Surgery with disc prosthesis versus rehabilitation in patients with low back pain and degenerative disc: two year follow-up of randomised study.
      patients allocated to undergo disc prosthesis experienced a statistically significant but not a clinically meaningful reduction in disability scores at 2-year follow-up as compared with patients allocated to receive pain rehabilitation.
      Neurostimulation, which includes spinal cord, dorsal root ganglion, motor cortex, and deep brain stimulation, provides pain relief through modulation of the nervous system. Spinal cord stimulation, the most widely used neurostimulation technique, involves placement of electrodes in the epidural space. This technique exerts its analgesic effects by stimulating large, fast-conducting sensory fibers, thereby inhibiting the slower-conducting A-delta and C nociceptive fibers responsible for pain transmission. In essence, conventional spinal cord stimulation acts by creating an area of paresthesia within the anatomical distribution of pain, though high-frequency and burst stimulation have been found to be more effective than traditional stimulation for alleviating pain without the accompanying paresthesias.
      • Bartleson J.
      • Deen G.H.
      Spine Disorders: Medical and Surgical Management.
      • Pope J.E.
      • Falowski S.
      • Deer T.R.
      Advanced waveforms and frequency with spinal cord stimulation: burst and high-frequency energy delivery.
      One of the most widely recognized indications for neurostimulation is refractory radicular pain in association with failed back surgery syndrome.
      • Deer T.R.
      • Mekhail N.
      • Provenzano D.
      • et al.
      Neuromodulation Appropriateness Consensus Committee
      The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee.
      Although the evidence supporting neurostimulation for axial LBP is limited, recent randomized studies
      • Deer T.R.
      • Mekhail N.
      • Provenzano D.
      • et al.
      Neuromodulation Appropriateness Consensus Committee
      The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee.
      • Kapural L.
      • Yu C.
      • Doust M.W.
      • et al.
      Novel 10-kHz high-frequency therapy (HF10 Therapy) Is Superior to traditional low-frequency spinal cord stimulation for the treatment of chronic back and leg pain: The SENZA-RCT randomized controlled trial.
      found high-frequency spinal cord stimulation to be more effective than conventional stimulation. Referral to a pain medicine specialist for a neurostimulation evaluation is typically reserved for patients who have failed other pain therapies including medications, injections, and physical modalities.
      Intrathecal drug delivery systems, also referred to as pain pumps or morphine pumps, administer medications directly to the intrathecal space.
      • Prager J.
      • Deer T.
      • Levy R.
      • et al.
      Best practices for intrathecal drug delivery for pain.
      A small caliber catheter is placed percutaneously in the intrathecal space and tunneled subcutaneously to a programmable reservoir pump that is typically implanted in the subcutaneous tissues of the lower abdominal region. Medications that are typically used as solo therapy or in combination include opioids (eg, morphine, hydromorphone, and fentanyl), local anesthetic medications (eg, bupivacaine), clonidine, and ziconotide, which is a novel N-type voltage-gated calcium channel blocker approved only for intrathecal use.
      • Deer T.R.
      • Prager J.
      • Levy R.
      • et al.
      Polyanalgesic Consensus Conference 2012: recommendations for the management of pain by intrathecal (intraspinal) drug delivery: report of an interdisciplinary expert panel.
      Although the primary indication for intrathecal drug delivery is intractable cancer-related pain, patients with refractory and possibly inoperable LBP due to failed back surgery syndrome or, less frequently, spinal stenosis may occasionally be considered for intrathecal drug delivery.
      • Deer T.R.
      • Mekhail N.
      • Provenzano D.
      • et al.
      Neuromodulation Appropriateness Consensus Committee
      The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee.
      • Prager J.
      • Deer T.
      • Levy R.
      • et al.
      Best practices for intrathecal drug delivery for pain.

      Conclusion

      In the absence of a widely recognized classification system for pain syndromes, classifying LBP as mechanical or neuropathic provides a cohesive model for organizing the large body of knowledge surrounding the evaluation and treatment of LBP in daily clinical practice (Figure 6). The sensitivity and specificity of some historical and physical examination findings have been established for commonly occurring sources of LBP, including sacroiliac joint pain, radiculopathy, and lumbar spinal stenosis. However, red flag indicators of serious underlying pathology are accurate only for vertebral compression fracture and spinal malignancy. Diagnostic testing, including electrodiagnostics and injections, can be useful in identifying the source of LBP, and adherence to established guidelines governing diagnostic imaging can potentially diminish the risk of unnecessary resource utilization. Multiple pharmacological trials exist for both axial and radicular pain; however, the long-term outcomes of commonly used drugs remain mixed. For carefully selected patients with sacroiliac joint and facet-related LBP, radiofrequency denervation techniques can provide sustained pain relief. For patients with radicular pain, transforaminal ESIs and neurostimulation may provide short- and longer-term pain relief, respectively. The indications for performing the various lumbar spine operations are complex and depend, in part, on individual patient factors. However, the general indications for commonly performed operations include spinal decompression for radicular symptoms and spinal fusion or disc prosthesis for discogenic LBP. A broad array of physical modalities and psychological treatments can improve pain and functioning, but individual patient preferences may influence treatment adherence.
      Figure thumbnail gr6
      Figure 6Summary of clinical and anatomical characteristics of axial LBP and radicular pain. EBM = evidence-based medicine; LBP = low back pain.

      Supplemental Online Material

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