Week 5: Low Back Pain

Question 1

Radiculopathy

Answer 1

(Pinched nerve) injury or damage to nerve roots in the area they leave the spine that may result in pain, loss of sensation and/or motor function depending on the severity of symptoms

Question 2

Acute low back pain (LBP)

Answer 2

up to 12 weeks

chronic LBP - 3 months or greater

Question 3

Lumbago

Answer 3

often refers to acute back pain or a strain, typically to either the quadratus lumborum muscle or the paraspinal muscles

Question 4

Sciatica

Answer 4

often used to describe lumbosacral radiculopathy, more specifically pain distributed along the sciatic nerve (L4, L5, S1, S2, S3)

Question 5

Classifying Low Back Pain in Primary Care

Answer 5

1. a problem beyond the lumbar spine (e.g., kidney stones, hip pathology)
2. a serious disorder affecting the lumbar spine (e.g., epidural abscess, vertebral fracture, spondylolysis, spondylolisthesis)
3. low back pain occurring with radicular pain (e.g., related to intervertebral disc herniation)
4. neurogenic claudication (e.g., related to central spinal canal stenosis)
5. nonspecific low back pain - 90% of low back pain in primary care

Question 6

Constructing a Differential Diagnosis: Acute LBP

Answer 6

. LBP due to disorders of the musculoskeletal structures
Nonspecific (mechanical) back pain
Specific MSK back pain: clear relationship between anatomic abnormalities seen on imaging and symptoms
Lumbar radiculopathy due to herniated disc, osteophyte, facet hypertrophy, or neuroforaminal narrowing
Spinal Stenosis
Cauda equina syndrome

2. LBP due to systemic disease affecting the spine
   Serious and emergent (requires specific and often rapid treatment)
   Neoplasms
   Infection
   Serious but nonemergent (requires specific treatment but not urgently).
   Osteoporotic compression fracture
   Inflammatory arthritis
3. LBP due to visceral disease (serious, requires specific and rapid diagnosis and treatment) - could involve the pelvis, renal structures, GI structures, etc.

Question 7

Ddx: acute LBP with radiculopathy

Answer 7

Question 8

Red flag findings

Answer 8

Question 9

Cauda Equina Syndrome

Answer 9

compression and disruption of function to cauda equina (namely L3-L5 nerve roots), most commonly due to lumbar disc herniation (45% of cases, but only approx. 3% of lumbar disc hernations)
incidence 1:33,000-100,000, approx. 1000 new cases per year in US

classical symptoms:
new urinary retention or overflow incontinence, fecal incontinence
progressive motor or sensory loss - saddle anesthesia, lower motor neuron weakness, significant deficits that encompass multiple nerve roots

Diagnosis: imaging (MRI) is diagnostic gold standard

Urgent ER referral; requires surgical decompression within 24-48hrs

Question 10

Spinal Malignancy: Metastases

Answer 10

the most commonly tumours of the spine are metastases of other primary cancers: breast (21%), lung (19%), prostate (7.5%), renal (5%), gastrointestinal (4.5%), and thyroid (2.5%)
personal history of cancer
back pain (deep, aching), unexplained weight loss; possibly sensory loss, weakness or radiculopathy (with tumour growth)

Diagnosis: imaging (xray or MRI)
blood work (incl CBC) and symptoms depend on type of primary cancer

Urgent referral back to oncologist or palliative care

Question 11

Vertebral Fracture

Answer 11

a break in one or more spinal vertebrae that can result from trauma and metastatic disease but, in most cases, are the result of osteoporosis (at T11 - L2)
low bone density (smoking, alcohol, anorexia, medications, Vitamin D deficiency), female > 50 yrs, prolonged use of corticosteroids, trauma/fall, personal history of vertebral fracture
back pain (acute or chronic, localized) agg. with standing or walking, rarely radiculopathy

Diagnosis: imaging (CT) is diagnostic
tenderness over affected vertebra(e)

Urgent referral for imaging, may require surgical intervention

Question 12

Vertebral Infection: Osteomyelitis

Answer 12

the most common vertebral infection (particularly the vertebral body), often caused by hematogenous spread of Staphylococcus aureus
rare (4.8 cases per 100,000 in US), approx. 3-5% of all cases of osteomyelitis
recent spinal procedure/surgery (with 12 months), recent infection, wound in spinal region, Hx IV drug use, immunosuppression (incl. advanced age, diabetes, long term corticosteroid use, malnutrition, malignancy)
back pain (as infection progresses, pain localizes), fever (in 35-60% of cases); sensory loss, weakness or radiculopathy (in 33% of cases)

Diagnosis: imaging (MRI) is preferred
CBC often normal, ESR elevated, CRP elevated, blood cultures

Urgent ER referral; requires antibiotic therapy (IV and oral)

Question 13

Flow chart of LBP

Answer 13

Question 14

LBP with Radiculopathy: Etiology

Answer 14

L4-L5 (L5 nerve root) and L5-S1 (S1 nerve root) are most susceptible to injury
particularly flexible part of lumbar spine
bears more impact than thoracic and cervical spine

Approx. 90% of compressive lumbosacral radiculopathies occur at either of these levels.

Question 15

LBP with Radiculopathy: Epidemiology

Answer 15

Lumbosacral radiculopathy is common: 3 - 5% of population
male (40yr+) > female (50yr+) - 3:2
L5 radiculopathy is the single most common lumbar radiculopathy
Pain Experience: often described as tingling, electric, burning or sharp
Paresthesia: 63 to 72% of patients
Radiation of pain into lower limb: 35%
Numbness (anesthesia): 27%
Muscle weakness: present in up to 37%
Absent Ankle Reflexes: 40%
Absent Knee Reflexes: 18%

Question 16

LBP with Radiculopathy: Risk Factors

Answer 16

Social History:
Repetitive lifting and twisting motions
Chronic overloading of disc: driving occupations, Heavy industry work, Military
Lifestyle: smoking, overweight, sedentary
Medical History:
Prior trauma (fall, motor vehicle accident (MVA))
Multiple pregnancies
History of back pain
Chronic cough

Question 17

LBP with Radiculopathy: History Intake

Answer 17

Site: ask about the location of the back pain
Onset:
How and when the back pain developed
Pain may follow a heavy lifting, twisting or straining episode or repetitive stress trauma
Quality: pain is often described as throbbing, aching, sharp, dull, burning, pressure, numbness, tingling, or shooting
Radiation: assess dermatomal distribution
Time Course: consider how the back pain changed over time

Severity of pain experience: Scale of 1-10
Pain is typically worse with:
Increased intradiscal pressure
Valsalva, weight bearing, standing, walking, sitting for prolonged periods
Pressure increases:
Coughing, sneezing, straining (bowel movement)
Forward flexion of the lumbar spine
Pain is typically better with:
Extension of the lumbar spine
Recumbent position (knees flexed)

Severity of pain experience: Scale of 1-10
Pain is typically worse with:
Increased intradiscal pressure
Valsalva, weight bearing, standing, walking, sitting for prolonged periods
Pressure increases:
Coughing, sneezing, straining (bowel movement)
Forward flexion of the lumbar spine
Pain is typically better with:
Extension of the lumbar spine
Recumbent position (knees flexed)

Associated Signs and Symptoms:
Fever: typically associated with urinary tract infection, pneumonia and discitis.
Malaise: associated with a wide range of pathology but in the context of back pain consider discitis or malignancy.
Weight loss: associated with malignancy.
Early morning stiffness: associated with inflammatory arthritis (e.g. rheumatoid arthritis, ankylosing spondylitis).
Muscular spasms: may be associated with spinal fracture or primary muscular injury.

Key Medical History:
History of malignancy
Recent bacterial infections
Recent history of epidural or spinal surgical procedures
Medications: history of or current corticosteroid use
Patients should also be evaluated for social or psychologic distress that may be contributing. Assess ability to function in daily life.

Question 18

Disc Hernation

Answer 18

displacement of intervertebral disc material (nucleus pulposus or annulus fibrosis) beyond the intervertebral disc space
1-3% of patients with acute LBP; age 30-40, male: female 2:1
acute-chronic pain, paresthesia, sensory change, loss of strength or reflexes (depends on affected nerve root)

Diagnosis: SLR + Hancock rule
Straight Leg Raise (SLR) test - ipsilateral leg pain at less than 45-60o is positive for lumbar disc herniation
Well Leg Raise (WLR, aka. crossed SLR) test - reproduction of contralateral pain at less than 45o is positive for lumbar disc herniation

85-90% experience relief within 6-12 weeks without treatment

Question 19

Patterns of Disc Herniation

Answer 19

Bulging Disc
Loss/damage of annular fibers allows the nucleus pulposus to shift without herniation
Associated with trauma, repetitive stress or aging

Prognosis (without treatment):
Regression: 13%
Complete Disappearance: 11%

Herniated Disc – Protrusion (Prolapse)
Focal distension of the disc
Annulus fibrosis remains intact

Prognosis (without treatment):
Regression: 41%
Complete Disappearance: 0%

Herniated Disc – Extrusion
Nucleus palposus breaks through the annulus fibrosis
Remains in the disc

Prognosis (without treatment):
Regression: 70%
Complete Disappearance: 15%

Herniated Disc – Sequestration
Nucleus palposus breaks through the annulus fibrosis and is displaced from the site of extrusion.
Considered a subtype of of ‘‘extruded disc’’

Prognosis (without treatment):
Regression: 96%
Complete Disappearance: 43%

Question 20

Physical Exam Findings associated with Lumbar Disc Herniation

Answer 20

Question 21

Hancock Rule: Clinical Prediction Rule for Lumbar Disc Herniation

Answer 21

The diagnostic accuracy of multiple neurologic findings improves clinician ability to determine level of disc herniation if at least 3 of 4 findings are in concordance with a specific nerve root:
dermatomal pain location
sensory deficit
reduced reflex
motor weakness

Question 22

L2, L3, and L4 Radiculopathy

Answer 22

Distribution of Pain:
L2, L3, and L4 lumbar radiculopathies are considered a group
Marked overlap of the innervation of the anterior thigh muscles
An acute injury in the distribution of L2, L3, and L4 will most commonly present with
Radiating back pain to the anterior aspect of the thigh, which may progress into their knee, and possibly radiate to the medial aspect of the lower leg, into thefoot.

Physical Exam :
Motor Weakness: knee extension, hip adduction, and or hip flexion.
Paresthesia/Sensory Changes: anterior thigh along the area of pain
Absent Reflexes: patellar reflex (L4)
Activities that can make the symptoms worse include coughing, leg straightening, or sneezing.

Question 23

L5 Radiculopathy

Answer 23

Distribution of Pain:
In L5 radiculopathy, patients will oftencomplain of acute back pain, which radiates down the lateral leg into the foot.

Physical Exam:
Motor Weakness:
Big toe extension (extensor hallucis longus)
Foot eversion & inversion
Ankle dorsiflexion.
Hip abduction (gluteus minimus and medius)
Paresthesia/Sensory Changes:
Lateral thigh, lateral lower leg, dorsum of the foot
Absent Reflexes: none
Atrophy (chronic): extensor digitorum brevis and tibialis anterior.

Question 24

S1 Radiculopathy

Answer 24

Distribution of Pain :
S1 radiculopathy will cause radiation of sacral or buttock pain into the posterior aspect of the patient’s leg, into the foot, or the perineum.

Physical Exam:
Motor Weakness: plantar flexion
Paresthesia/Sensory Changes: sole, lateral foot and ankle, fourth and fifth toes
Absent Reflexes: ankle reflex (S1)

Question 25

Serious disorders affecting the Lumbar Spine

Answer 25

Spondylosis, spinal stenosis, spondylolysis, spondylolisthesis

Question 26

Spondylosis

Answer 26

an umbrella term for age-related degeneration of the spinal column (often involves degenerative disc disease and facet arthropathy)

Question 26

spinal stenosis

Answer 26

narrowing of the spinal canal, neural foramen and lateral recess which can lead to compression of the nerve roots and neurogenic claudication most commonly due to spinal osteoarthritis (degeneration of the vertebral bodies, joints and foramina due to “wear and tear”)

Question 27

Spondylolysis

Answer 27

weakness or stress fracture through the pars interarticularis a unilateral or bilateral defect through the pars interarticularis (most commonly affects L5, 90%) 6-18% population (14+); up to 50% young athletes (male:female, 2:1) risk associated with excessive lumbar lordosis, genetics (fHx) asymptomatic (90% of patients); insidious onset, recurrent axial low back pain exacerbated with activity or lumbar hyperextension, +/- radiculopathy Diagnosis: imaging is diagnostic increased lumbar lordosis, tight hamstrings, reduced lumbar ROM (esp. extension), tenderness overlying fracture site at diagnosis, 50-75% of bilateral spondylolysis will have spondylolisthesis

Question 27

spondylolisthesis

Answer 27

the slippage of one vertebral body with respect to the adjacent vertebral body the slippage of one vertebral body with respect to the adjacent vertebral body from degenerative, lytic (isthmic), traumatic, dysplastic, or pathologic causes (most commonly anterior translation of L5 on S1) 3-4% of patients with mechanical LBP adults, female > male, obesity, fHx (spondylolisthesis, scoliosis, spina bifida) intermittent and localized low back pain that radiates into buttock or posterior thigh; paresthesia, sensory change, loss of strength or reflexes (depends on affected nerve root) Diagnosis: imaging is diagnostic (used to grade as well) pain elicited with lumbar flexion and extension, tenderness over affected vertebral segment 75% are grade I and typically stable in older patients, may progress in puberty

Question 28

Spinal Stenosis

Answer 28

narrowing of the spinal canal, neural foramen and lateral recess which can lead to compression of the nerve roots and neurogenic claudication 3% with mechanical low back pain (LBP), 19.4% aged 60-69 years LBP with B/L lower extremity pain, numbness or loss of strength (depends on affected nerve root) agg. by ambulation, standing and lumbar extension neurogenic claudication: pain/discomfrot with walking or prolonged standing that radiates into one or both lower extremities (relieved by rest/ sitting, lumbar flexion) Diagnosis: imaging is diagnostic pain elicited with passive and active lumbar extension, neurologic exam (typically normal), pedal pulses symmetrical approx. 19% of patients who had an initial surgery eventually repeat surgery

Question 29

Evaluation - Imaging

Answer 29

Initial imaging is not indicated in the majority of patients with low back pain. due to very high prevalence of abnormal neuroimaging findings even in asymptomatic patients conservative management for 6 weeks is typically recommended before considering imaging (radiography, MRI, CT) UNLESS presenting with severe symptom intensity (causing diability) or red flag findings for conditions that require timely diagnosis to prevent serious consequences (e.g. cauda equina syndrome, malignancy, fracture and infection) MRI: considered the best initial examination Provides axial as well as sagittal views Demonstrates discs, ligaments, nerve roots, and epidural fat, as well as the shape and size of the spinal canal. MRI is more sensitive and specific than plain radiographs for the detection of spinal infection and malignancy. CT with contrast: used in patients who cannot undergo MRI Contraindications to MRI: pacemaker or defibrillator device Plain Radiographs: those who have risk factors for malignancy or fractures

Question 30

Acute Low Back Pain Considerations for Imaging (FLOW CHART)

Answer 30

Question 31

Management

Answer 31

There are three categories of radicular symptoms and signs: Mild radiculopathy is considered a sensory loss and pain without motor deficits Moderate radiculopathy is the sensory loss or pain with mild motor deficits Severe radiculopathy is considered sensory loss and pain with marked motor deficits. Management of patients underlying symptoms will depend on the severity of the radiculopathy, namely severe radiculopathy increases need for earlier imaging. 

Question 32

Prognosis

Answer 32

Most cases of lumbosacral radiculopathy are self-limited. Spontaneous improvement is very common without treatment. Counseling is crucial for patients with radicular symptoms since most cases are mild and will resolve within six weeks.  It is vital to discuss weight loss reduction, as the vast majority of these patients will have an elevated body mass index.  Concerns arise when a patient's symptoms worsen or are severe. Severe symptoms warrant further imaging and/or emergent surgical intervention.

Question 33

Patient Education

Answer 33

Disease education: Provide reassurance: low likelihood of serious pathology most cases are self-limited and resolve with conservative management in 6-8 weeks Stay active (moderate level) and return to normal activities as soon as possible; avoid bed rest and aggravating movements Pain management includes nonpharmacologic (physiotherapy) and pharmacologic options What they need to look out for: Symptoms persisting for over six weeks may benefit from additional interventions (e.g. injections) Red Flag symptoms that warrant an immediate emergent evaluation and potential surgical consultation

Question 34

Complications

Answer 34

Lumbar radiculopathy is often self-limited but can be extremely painful. An immediate complication that can arise from acute radicular pain is the loss of function and decreased quality of life. Emergent complications include cauda equina syndrome and severe lumbar radiculopathy. Both of these complications often require emergent surgical decompression.  Patients who do not improve within the six to twelve weeks following the onset of pain can develop chronic pain. Slowly progressing radicular symptoms can eventually lead to muscle atrophy as the nerves innervating the lower extremity musculature are affected. Deconditioning can occur over time.