Approach to Low Back Pain

Definition of Low Back Pain

Low back pain (LBP) is defined as pain, muscle tension or stiffness localized below the costal margin and above the inferior gluteal folds, with or without leg pain (sciatica). “Diagnostic triage” after excluding non-spinal causes of low back pain classifies LBP into 3 broad categories:

  1. Specific spinal pathology (<1%)
  2. Radicular syndrome (5-10%)
  3. Non-specific low back pain (90-95%; diagnosis of exclusion)

Non-specific low back pain is subclassified according to the duration:

  1. Acute: <6 weeks
  2. Subacute: 6-12 weeks
  3. Chronic: >12 weeks
  4. Recurrent: period of LBP lasting more than 24 h preceded and separated by a period of at least 1 month without LBP (de Vet definition)

Origin of Back Pain

Soft tissue (Lumbar strain/sprain)NeoplasmPelvic organ disease
Muscle/fascia (Myofascial pain)InfectionRenal disease
Discs (Herniated discs, Discogenic pain)InflammatoryAbdominal aortic aneurysm
Joints (Facet joints, Sacroiliac joint)MetabolicGastrointestinal disease
Bone (Vertebral fractures, Spondylolisthesis, Kyphosis, Scoliosis)

Nature of Back Pain

Mechanical vs Inflammatory Back Pain:

inflammatory vs mechanical back pain

ASAS criteria for inflammatory back pain will be discussed later.

Back pain with leg pain:

Back pain with leg pain must be classified as either referred or radicular pain whenever possible.

Referred painRadicular pain
Back > LimbLimb > Back
Dull acheLancinating
Above kneeBelow knee (usually; S1 occasionally felt in thigh & buttock only)
Unilateral or BilateralUnilateral
No aspect (front/back/side) or edgeAspect and edge
No sensory symptoms+/- sensory symptoms (inflamed root = pain; non-inflamed root = paresthesia)
No neurological signs+/- neurological signs
Straight leg raise (SLR) – ?back pain worseSLR – leg pain worse

Vascular claudication vs Neurogenic claudication:

Vascular ClaudicationNeurogenic Claudication
Triggered by increased demand across arterial stenosis. Relieved by rest.Triggered by lumbar extension worsening spinal stenosis. Relieved by lumbar flexion.
Pain reliably comes after a fixed amount of exertion (e.g. specific walking distance)Pain may come with minimal exertion (e.g. standing in line, going down stairs)
Pain comes with activity even if back is flexed (e.g. riding a bicycle)Pain does not occur with exertion in lumbar flexion (e.g. riding a bicycle or walking uphill)
Cramping pain – distal to proximalNumbness, aching – proximal to distal

Natural History of Low Back Pain

  1. At least 50% of these people will recover within 2 weeks and 90% within 6 weeks, but recurrences are frequent.
  2. After 6 weeks, improvement is slowed.
  3. Cumulative risk of at-least 1 recurrence within a 12 month period is 73%.
  4. Only 5% of people with an acute episode of low back pain develop chronic low back pain and related disability.

Flags in Back Pain

  1. Red flags: Indicate potential serious pathology
  2. Yellow flags: Risk factors for chronicity, the psychosocial barriers to recovery
  3. Orange flags: Psychiatric issues in patients with back pain
  4. Blue flags: Occupational issues
  5. Black flags: Organizational barriers to recovery

5 Goals of Low Back Pain Assessment

There are 5 main goals of low back pain assessment and are listed sequentially below:

  1. Ruling out potentially serious spinal pathology (Red flag signs)
  2. Ruling out specific causes of Low Back Pain
  3. Ruling out substantial neurologic involvement
  4. Evaluating the severity of symptoms and functional limitations
  5. Identifying the risk factors for chronicity (Yellow flag signs)

Red Flag Signs in Low Back Pain

Red flag signs are the indicators of serious spinal pathology and suggests for additional investigations or urgent evaluation.

Mnemonic: TUNIC

Red flag signs are used to rule out following causes of low back pain and the questions and examinations must be directed to rule them out:

1. Trauma (Spinal fracture)
2. Unresponsiveness to therapy >1 month
3. Neoplasm (Spinal cancer)
4. Infection (Spinal infections)
5. Cauda equina syndrome

Additional red flags for children:

  1. Age <4 years
  2. Pain that interferes with daily activity
  3. Limp or altered gait
  4. Back pain despite no clear mechanism of injury
  5. Acute or repetitive trauma
AllDuration of pain > 1 month
Bed rest with no relief
CancerAge ≥ 50 years
History of cancer
Unexplained weight loss
Neurologic findings
Compression fractureAge ≥ 50 years (> 70 years is more specific)
Significant trauma
History of osteoporosis
Corticosteroid use
Substance abuse
InfectionFever or chills
Recent skin or urinary tract infection or catherterization
Injection drug use
Fever (temperature > 100°F or 38°C)
Tenderness over spinous processes
Cauda equina syndromeSaddle anesthesia
Bilateral sciatica or leg weakness
Difficulty urinating
Fecal incontinence
Progressive motor or sensory deficit

Ruling out Specific Causes of Low Back Pain

Classic discogenic history (factors that worsen pain):

  • Sitting > Standing > Lying
  • Arising from seated position
  • First 20-30 minutes of day
  • Coughing, sneezing, straining (Valsalva maneuver)
  • Lifting weight out in front of the body
  • Twisting
  • Bending at waist

Differentials of back pain according to age groups:

  1. Children: Scoliosis, Spondylolisthesis, Infections, Calve’s disease
  2. Adolescents: Scheuermann’s disease, Scoliosis, Mechanical back pain, Spondylolysis, Infections, Adolescent intervertebral disc disease
  3. Young adults: Mechanical back pain, PIVD, Spondylolisthesis, Spinal fracture, Ankylosing spondylitis, Coccydynia, Infections, Spinal stenosis
  4. Middle aged: Mechanical back pain, PIVD, Scheuermann’s disease and old fracture, Spondylolisthesis, Rheumatoid arthritis, Spinal stenosis, Paget’s disease, Coccydynia, Spinal metastases, Pyogenic osteitis of spine
  5. Elderly: Osteoarthritis, True senile kyphosis, Osteoporosis +/- fracture, Osteomalacia +/- fracture, Spinal metastases
DiseaseFeaturesRelation to movement/position and Response to treatment
Annular tearAge – 4th decade
Non-radicular axial back pain
Discogenic history
Improved with passive extension, side gliding, proper body mechanics
Paramedian protrusions & herniationsAge ~40 yrs
Back + Leg pain (In variable percent)
Discogenic history
Radiculopathy: 90-95% involve L5-S1 (S1 may present as calf cramps)
Recurrences – common
Positive dural tension signs
Pain increases with ipsilateral weight bearing on sitting/standing
Comfortable in lateral decubitus or supine with hips and knees flexed
Larger herniations – uncomfortable in standing and extension
Pain centralizes with extension or side gliding
Pain peripheralizes with flexion activities or manipulation
Lateral & foraminal herniationsAge ~60 yrs
Leg pain > Back pain
May not have discogenic history
L4-L5 (60%); L3-L4 (30%); L5-S1 (<10%)
Recurrences – uncommon
Positive dural tension signs
Pain is worst with standing or walking erect
Often uncomfortable in bed; many sleep sitting
Sitting usually relieves pain
Generally more resistant to mobilization, centralization and traction
Upper lumbar protrusions and herniations (above L4)Age ~55 years
Risk: prior L4-S1 fusions
L1-L2, L2-L3: groin, anterior thigh, back pain
L3-L4: extension to knee, medial leg
Positive dural tension sings
Sequestered disc herniations and disc fragmentsDiscomfort during Valsalva maneuver or lifting abruptly resolves
Back pain decreases and lower extremity pain increases
Cauda equina syndromeRisks: Tumors (50%), Central L3-L4, L4-L5 discs
Bladder incontinence
Bowel incontinence
Sexual dysfunction
Diminished perineal sensation
Bilateral lower extremity neurologic complaints or pain
Lumbar stenosisAge >55 years
Spontaneous, insidious onset with gradual progression
Central stenosis – bilateral symptoms, fairly symmetrical but non-specific distribution
Lateral or Foraminal stenosis – unilateral symptoms, fairly specific dermatomal distribution
Increased symptom on extension
Symptoms: walking (neurogenic claudication) > standing > lying
Sitting – often asymptomatic
Valsalva – doesn’t affect pure stenosis
Flexion relieves symptoms (going uphill, bicycling, shopping cart sign)
Flexion exercises may provide transient relief only; Chairs and corsets that place patient in flexion may provide relief
Spondylolisthesis – IsthmicAge – Late childhood/Adolescence
Risk: Athletes (sports with significant lumbar extension & rotation – gymnastics, dance, martial arts, crew)
L5-S1 involvement
Intervertebral slip by inspection or palpation
Worsened with extension
Segmental hypermobility by use of manual passive physiological intervertebral motion test
Spondylolisthesis – DegenerativeF>M; Old age
L4-L5 involvement
Unilateral radicular symptom (due to foraminal stenosis)
Intervertebral slip by inspection or palpation
Worsened with extension
Segmental hypermobility by use of manual passive physiological intervertebral motion test
TumorsAge – 20 (Benign tumors); 50 (Malignancy)
Constant pain awakening the patient or persists beyond 1 month despite treatment
Smoking history
B symptoms, Dry cough, Change in bowel/bladder habit
Benign – Osteoid osteoma and Osteoblastoma (pain relived by aspirin)
Malignant primary tumor – Multiple myeloma
Metastatic tumors (bronchogenic, breast, prostatic, renal) – 2 patterns of pain (mild local complaints progressing to severe radiculopathy OR sudden pain due to pathological fracture or instability)
Unrelated to position
Herpes Zoster radiculopathyHistory of cancer
Spontaneous onset
Pain may precede vesicular lesion by upto 3 weeks and usually lasts through eruption period
10-20% have post-herpetic pain (common in older patients)
Single, unilateral dermatome involved (thoracic root in 50%) – initially dysesthesia, full paresis occurs within hours to days (55% recover fully)
No relation with position, movement or activities
Diabetic radiculopathyMiddle-aged or Elderly
Pain – constant and worse at night
Sensory and Motor complaints common
ArachnoiditisRisks: Disc space infections, Subarachnoid hemorrhage, Multiple surgeries, Intrathecal drugs, Radiation therapy, Myelography
Reproduction of lumbar or lower extremity symptoms with long stride or cervical and thoracic flexion
No discogenic history
Sciatic neuropathyBlunt/penetrating injuries or Traction injuries (hip surgery) or Tumors or Compression (Wallet sciatica, Piriformis syndrome)
Neurologic complaints and deficits are more common than pain
No discogenic history
No relation to spinal posture or Valsalva maneuver
Piriformis syndromeDouble devil (Trigger point pain + Sciatic nerve entrapment)
Trigger point pain – Back pain, buttock pain, posterior thigh pain
Sciatic nerve entrapment – Paresthesias &/or numbness in calf and foot
Externally rotated attitude of affected leg
Reproduction of symptoms:
1. Freiburg’s sign – Forceful internal rotation of flexed hip
2. Bonet’s sign: Add adduction (i.e. FAIR test)
3. Pace maneuver: Resisted abduction and external rotation of hip in sitting position
Piriformis tenderness (Along the line drawn from greater trochanter to sacroiliac end of greater sciatic foramen in lateral position with affected limb up and hip flexed to 90 degrees)
Facet joint pathology (Facet syndrome)Conditions associated – Osteoarthritis, Instability, Acute subluxation
Onset relates to increased axial loading and hyperextension activities
Axial back pain
No localizing neurologic signs
Pain with extension and ipsilateral side bending and rotation
Pain: Standing > Sitting
Dramatic response to facet manipulation and facet joint injection
StrainsUncommon but over-diagnosed
Pain with stretch or prolonged contraction of involved muscle
Sacroiliac joint painRisks: Mid-pregnancy to postpartum period, Seronegative spondyloarthropathy, After trauma, After extensive spinal fusion
Gradual or sudden onset
Pain in sacroiliac region or buttock (usually unilateral); may cause posterior thigh or groin pain
3 positive out of 5: Distraction, Compression, Thigh thurst, Ganselen’s test, Sacral thurst
Patient feels best when reclining
Pain with vasalva maneuver may be present
Spinal fracturesTraumatic or Osteoporotic (postmenopausal and prolonged corticosteroid use)
Commonly involves T10-L1
May result in leg pain and occasionally neurologic symptoms
Increased pain with changing positions
Generally worse in spinal flexion
Ankylosing spondylitisYounger male (AS, Reiter’s)
Lower lumbosacral pain
Morning stiffness (“gel”) of 2-3 hours (20-30 minutes in disc disease)
Positive modified Schober’s test
Reduced chest expansion
Enthesopathy (heel pain)
Radiographic sacroilitis
Elevated ESR or HLA-B27
Pain improved with activity
Spinal infectionsRisks: Immunosupressed patients, Prior sepsis, Prior spinal procedures
Constant pain awakening the patient
Radiculopathy, fever and constitutional symptoms may be present
Epidural abscess – progresses quickly
Vertebral osteomyelitis – average delay to diagnosis is 3 months (TB has more slower course)
Pain doesn’t relate well to position or movement
Vascular claudicationHistory of smoking, diabetes or hyperlipidemia
Sudden or gradual onset
Asymmetrical involvement of calves
Leriche syndrome – buttock claudication and impotence due to aorto-iliac occulsive disease
Increased work demands on lower extremity musculature worsen symptoms
Walking uphill increases symptoms
Claudication symptoms caused by cycling and walking are relieved by cessation of activity
Standing, sitting or flexion do not reproducibly relieve symptoms
Abdominal aortic aneurysmMedical background same as for vascular claudication
Pain – Lumbar, constant, gradually worsens
Unrelated to motion
ViscerogenicProstatitis, Renal disease, Stomach and duodenal diseases, Pancreatic diseases, Retroperitoneal disease, Gynecologic disorders
Pain modified by state of activity of viscera
Unrelated to position or motion
Nonorganic or PsychogenicMalingering – Intentional
Depression, Anxiety, Hysteria – Unintentional
See the Wadell signs below (DoREST mnemonic)

Diagnosis of Pseudospine pain

ConditionDiagnostic keys
Abdominal aortic aneurysmAge >50 years
Abdominal and back pain
Pulsatile abdominal mass
Curvilinear aortic calcification in X-rays
EndometriosisWomen of reproductive age
Cyclic back and pelvic pain
Pelvic inflammatory diseaseYoung, sexually active woman
Systemically ill (fever, chills)
Discharge, Dysuria
Ectopic pregnancyMissed period
Abdominal and/or pelvic pain
Positive pregnancy test
ProstatitisMen >30 years
Low back and perineal pain
Tender, boggy prostate gland
NephrolithiasisFlank and groin pain
Costovertebral angle tenderness
PancreatitisAbdominal pain radiating to back
Systemic signs
Elevated serum amylase
Perforated duodenal ulcerAbdominal pain radiating to back
Air under diaphragm on erect Chest X-ray
FibromyalgiaYoung to middle-aged woman
Widespread pain
Multiple tender points
Disrupted sleep, fatigue
Normal radiographs and lab values
Polymyalgia rheumaticaAge over 50-60 years
Hip or shoulder girdle pain and stiffness
Elevated ESR
Dramatic response to low dose prednisone
Seronegative spondyloarthropathiesYounger male (AS, Reiter’s)
Lower lumbosacral pain
Morning stiffness (“gel”)
Improvement with activity
Positive modified Schober’s test
Reduced chest expansion
Enthesopathy (heel pain)
Radiographic sacroilitis
Elevated ESR or HLA-B27
Forrestier’s disease (DISH)Age >50-60 years
Thoracolumbar stiffness > pain
Flowing anterior vertebral calcification over 4 contiguous vertebrae
No sacroiliac invovlement
Normal ESR and CRP
Piriformis syndromeButtock and leg pain
Pain on resisted hip external rotation and abduction
Transgluteal or transrectal tenderness
3 or more wedged vertebrae with endplate irregularities
Trochanteric bursitis, gluteal fasciitisGluteal and leg pain
Pain lying on affected side or with crossed-leg
Pain or tenderness over greater trochanter frequently with iliotibial band tightness and tenderness
OsteoporosisWoman >60 years
Severe pain (fractures)
Aching dull thoracic pain relieved in supine position (mechanical)
Loss of height, increased thoracic kyphosis
OsteomalaciaDiffuse skeletal pain or tenderness
Increased ALP
Paget’s diseaseBone pain: low back, pelvic, tibia
Nerve root entrapment (hearing loss, spinal stenosis)
Increased ALP
“Picture frame” vertebra in X-rays
Proximal motor neuropathy>50 years
Diffuse leg pain, worse at night
Proximal muscle weakness
Malignancy>50 years
Back pain unrelieved by position change – night pain
Previous history of malignancy
Elevated ESR

Evaluating the Severity of Symptoms and Functional Limitations

There are numerous rating scales and scoring systems to assess the severity of low back pain. A simple assessment tool developed by Higuchi may be useful at bedside.

a. Pain intensity: 3 parameters scored on scale of 0 (no pain) to 10 (worst pain) and average of 3 is calculated

  1. Current pain
  2. Average pain during last 6 months
  3. Worst pain during last 6 months

b. Pain interference:

  1. Almost daily back pain during past 6 months: 1 point
  2. Affect on work activity:
    1. Sick leave: 2 points
    2. Other: 1 point
  3. Non-work activity affected: 1 point
  4. Treatment during last 6 months:
    1. Alternative medicine: 1 point
    2. Physician: 1 point
    3. Both: 2 points


  1. Mild: Pain interference <3, Pain intensity <5
  2. Moderate: Pain interference <3, Pain intensity >/= 5
  3. Severe: Pain interference >/= 3

Source: Higuchi, Y., Izumi, H., & Kumashiro, M. (2010). Development of a simple measurement scale to evaluate the severity of non-specific low back pain for industrial ergonomics. Ergonomics, 53(6), 801–811. doi:10.1080/00140139.2010.489652

Yellow Flag Signs in Low Back Pain

These are psychosocial factors shown to be indicative of long term chronicity and disability.

Mnemonic: ABCDEFS

Attitude: Negative
Behavior: Fair avoidance
Compensation issues
Depression and anxiety
Expectation: Passive treatment better than active (expectation that pain will increase with work and activity)
Financial problems
Social issues: History of sexual abuse, physical abuse, lack of support, older age, overprotective family

  • A negative attitude that back pain is harmful or potentially severely disabling
  • Fear avoidance behavior and reduced activity levels
  • An expectation that passive, rather than active, treatment will be beneficial
  • A tendency to depression, low morale, and social withdrawl
  • Social or financial problems

Inflammatory Back Pain and Axial Spondyloarthritis

Inflammatory back pain mnemonic (Positive if 4 out of 5): ERIN40

  1. Exercise – improvement
  2. Rest – no improvement
  3. Insidious onset and persisting for >3 months
  4. Night pain
  5. <40 yrs age at onset

European Spondyloarthropathy Study Group (ESSG) Criteria

Inflammatory spinal pain OR Synovitis and 1 of the following: AS DIP

  1. Alternating buttock pain
  2. Sacroiliitis
  3. Diarrhea, cervicitis or urethritis occurring within 1 month before the onsent of arthritis
  4. Inflammatory bowel disease
  5. Psoriasis
  6. Positive family history

ASAS classification for axial spondyloarthritis: SPINEACHE mnemonic

1. Sacroilitis on imaging (by radiograph or MRI) + >/= 1 of SPINEACHE OR
HLA-B27 + >/= 2 of SPINEACHE
a. Sausage digit (dactylitis)
b. Psoriasis-positive family history of SpA
c. Inflammatory back pain
d. NSAID good response
e. Enthesitis (heel)
f. Arthritis
g. Chron’s colitis/disease – elevated CRP
h. HLA-B27
i. Eye (Uveitis)

New York Criteria for Ankylosing Spondylitis

Bilateral sacroiliitis grade 2 or higher OR Unilateral sacroiliitis grade 3 or higher and 1 of the following:

  1. Inflammatory back pain
  2. Limitation of lumbar movements in sagittal and frontal planes
  3. Decreased chest expansion (1 inch or less at 4th ICS)

ACR Criteria for Diagnosis of Fibromyalgia

Mnemonic: WOKE UP STIFF (this also reminds that non-restorative sleep and morning stiffness are also important features of this disorder although not included in the criteria)

  1. Widespread pain AND 11 out of 18 tender points (9 pairs)
  2. Tender points (9 pairs):
    • Occiput: suboccipital muscle insertion
    • Knee: medial fat pad
    • Epicondyle: 2 cm distal to lateral epicondyles
    • Upper outer quadrant of buttocks
    • Parasternal: second costochondral junction
    • Supraspinatus muscles: at origins, above scapula spine
    • Trapezius muscles: upper border, midpoint
    • Intertransverse spaces at C5-C7, anterior aspects
    • Femoral greater trochanter: posterior to prominence
    • Four kg: approximate force on digital palpation

History Taking For Low Back Pain

In general, a history must obtain following informations:

  1. Acute/Subacute/Chronic/Recurrent back pain
  2. Axial/Radicular/Referred pain
  3. SOCRATES of pain (Inflammatory vs Mechanical; Discogenic/Stenosis/Non-spinal, etc.)
  4. ADL (Activities of daily living) affected (Severity of Symptoms)
  5. Red flag signs
  6. Yellow flag signs in cases of subacute and chronic back pain
  7. Screening question for depression in chronic back pain: Ask 2 questions (highly sensitive but not specific)
    • Have you often been bothered by feeling down, depressed or helpless?
    • Have you often had little interest or pleasure in doing things?
    • If ‘yes’ response for both the 2 questions above: Is this something you would like help with? (increases specificity)
  8. Patient’s occupation, demands, ICE history (Ideas, Concerns and Expectations)

Physical Examination in Low Back Pain

  • Radiculitis = lower limb pain and neurological signs
  • Nerve root sleeve involvement = neurological signs (conduction block), radicular pain (radiculitis), back pain (inflammation of dura)
low back pain neurological examination
low back pain examination
examination of back
Source: Textbook of Orthopedics by John Ebnezar

List – deviation to opposite side: shoulder type PIVD
List – deviation to same side: axillary type PIVD

Braggard’s test involves dorsiflexing the foot after lowering the hip flexion by 10-15 degrees from point of SLR positive. Neri’s test involves flexing the neck. SLR detects tension on nerve root L4, L5, S1. Reverse SLRT or Femoral nerve stretch test detects tension in the L2–L4 nerve roots. With the patient prone, pain elicited in the anterior thigh with extension of the hip or flexion of the knee confirms a positive RSLR test.

Wadell’s sign (Non-organic cause of Back Pain)

Wadell’s sign indicate psychological distress (nonorganic causes of pain): 3 out of 5 is significant

Explore these signs in cases of non-specific back pain.

Mnemonic: DOReST

  • Distraction testing: Inconsistent responses noted with the same test when performed in a standard fashion and when the patient’s attention is distracted (eg. flip test – seated straight leg raising without discomfort versus radiating pain with supine straight leg raise)
  • Overreaction: Disproportionate verbalization, facial expression, muscle tension, tremor, collapsing, and even profuse sweating (single most important sign but observer dependent)
  • Regional disturbances: in strength and sensation that do not correspond with nerve root innervation patterns
  • Stimulation testing: Pain on simulated axial loading by pressing on the top of the head or simulated spine rotation
  • Tenderness: Localized tenderness that is does not follow a dermatomal or expected referral pattern; superficial light touch over the low back causing severe discomfort, or deep palpation causing widespread discomfort through the thoracic spine or sacrum or hips

Apply 4 tests:

  1. Skin roll test: gently roll loose skin of lower back
  2. Twist test: gently rotate patient’s torso at hips
  3. Head compression test: apply small load to top of head
  4. Flip test: test straight leg raise when seated and supine


backpain syndromes


  1. da C Menezes Costa L, Maher CG, Hancock MJ, McAuley JH, Herbert RD, Costa LO. The prognosis of acute and persistent low-back pain: a meta-analysis. CMAJ. 2012 Aug 7;184(11):E613-24. doi: 10.1503/cmaj.111271. Epub 2012 May 14. PMID: 22586331; PMCID: PMC3414626.
  3. Low Back Pain – Handbook
  4. Evidence based management of Low back pain

6 Viewpoints 💬 on “Approach to Low Back Pain”

  1. Thank you for this article, I am currently using it to study for my NP Finals. It is very thorough and comprehensive.

  2. Thank you for the great explanation!
    Could you tell us the source of each photograph you used from a book or site?
    Thank you in advace!

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