A Concise Approach to Low Back Pain

By :Hieder A`ala

601MUST UNIVERSITY

Prevalence 60-80% of people will have LBP sometime in their

lives. 30% are referred to Ortho; 3% admitted; 0.5%

operated. 90% LBP resolves in 6w, 75% may experience

symptoms & disability one year after initial consultation.

The prevalence of LBP has changed little over the years, but the associated disability has increased four fold  

In the UK certified incapacity for LBP was 120 milion days in 1996 

14 million consultations annually. Overall cost of LBP was £6 billion

Why take it seriously?

Acute low back pain is often recurrent, Predisposes to chronic pain and disability A warning of potential future trouble Impacts on the quality of life Lost days of productivity Huge cost of incapacity payouts Enormous burden on healthcare costs when

chronic

AETIOLOGY AND CLASSIFICATIONS 1.congenital: 2.acquired :

• Mechanical Low Back Pain• Traumatic•  Infective •  Inflammatory• Neoplastic • Degenerative • Metabolic• Endocrine  • Idiopathic • Psychogenic• Visceral• Vascular • Gynaecological

1% tumor, infection,

inflammatory arthritis

2% visceral

97%

“mechanical”

Types of Back Pain:

Discogenic back pain • annulus fibrosus when it is stretched with a

bulging disc • Outer1/3 has sensory innervation, • radial fissuring is associated with painful discs

Radicular back pain • pain extending to the buttock and/or leg • disc herniation , spinal stenosis or intraspinal

pathology

Psychogenic back pain • must exclude organic pathology

Types of Back Pain Facet-joint pain

• Studies of provocative intra-articular injection techniques demonstrated local and referred pain into the lower extremity from the lumbar facets.

• The fibrous capsule of the facet joint contains encapsulated, unencapsulated, and free nerve endings.

Sacroiliac pain • variable local and referred pain patterns into regions of the

buttock, lower lumbar area, lower extremity, and groin.

Muscular pain (myofascial pain ) • MP is characterized by muscles that are in a shortened or

contracted state, with increased tone and stiffness, and that contain trigger points

Types of Back Pain Viscerogenic Back Pain

• may be derived from disorders of the kidneys or the pelvic viscera, lesions of the lesser sac, and retroperitoneal tumors

• Backache is rarely the sole symptom of visceral disease.

Vascular Back Pain• Abdominal aortic aneurysms or peripheral vascular

disease (PVD) may give rise to backache or symptoms resembling sciatica

• Intermittent claudication intermittent pain in the calf”associated with PVD may on occasion mimic sciatic pain produced by root irritation, but the history of specific aggravation by walking and relief by standing still will make the clinician look for signs of peripheral vascular insufficiency.

Three syndromes are recognized in which spinal disorders cause both back and neurologic dysfunction. Examples are :

1. Herniated disc causing a single nerve root compression (leg pain > back pain).– Clinical features include positive straight leg-raising test and

radicular pain in the limb disproportionate to pain in the spine. Loss of strength, reflex, and sensation occurs in the territory of the compressed root.

2. Lateral recess syndrome (leg pain ≥back pain). Single or multiple nerve roots on one or both sides become compressed. Pain in the limb is usually equal to or greater than that in the spine. Symptoms are brought on by either walking or standing and are relieved with sitting. Testing by straight leg raising may be negative.

3. Spinal stenosis (leg pain < back pain). Multiple nerve roots are involved, and the pain in the spine is significantly greater than that in the limb. Symptoms develop with standing or walking. Impairment in bowel and bladder dysfunction as well as sexual dysfunction may occur.

History taking….

Past history of similar symptoms, course of treatment, and response

Onset of current episode, mechanism of injury, and initial location of pain

Current location and character of pain, associated symptoms, and influencing factors

Pain status: improving, deteriorating, or plateaued? Red flags (eg, neurologic deficits, bowel or bladder

dysfunction, systemic illness) Physical and functional impairment due to pain

Identify complexities in management

Involvement with a disability compensation claim, Symptom magnification, drug-seeking behaviour,

past history of chronic pain, and psychosocial stressors.

Past medical history, family history, health habits, exercise habits, social and occupational history

Dependency, sleeplessness, and emotional distress resulting from or contributing to the pain.

Points to note….. Lumbar spine tolerates a higher degree of stenosis

than the cervical or thoracic region

The discs, facet joints & capsules, ligamentum flavum are affected by degenerative processes.

The dimensions of the spinal canal and foramen are influenced by dynamic and postural factors

The foramina decrease in size while the nerve roots increase in diameter as you move down the spine. Thus the lumbar spine is most commonly affected

. 

Points to note…..

The objective of a detailed history and thorough clinical examination are to avoid missing cauda equina syndrome…

The MPS case book has highlighted the following points ( slides 9 -14)

What is Cauda Equina Syndrome?

Cauda Equina Syndrome is a collection of signs and symptoms resulting from compression of the bundle of nerve roots emerging from the end of the spinal cord below the 1st lumbar vertebra.

The classic syndrome is characterised by severe LBP with bilateral sciatica associated with saddle anaesthesia, urinary retention and bowel dysfunction.

Causes of cauda equina syndrome

Traumatic injury Herniated inter-vertebral disc Secondary to surgery, spinal or epidural

anaesthesia, spinal manipulation Tumours Infections Vascular problems Spina bifida Spinal stenosis Late-stage ankylosing spondylitis

Cauda equina syndrome - Red flags

Severe low back pain with bilateral or unilateral sciatica

Bladder or bowel dysfunction Anaesthesia or paresthesia in perineal

region or buttocks Significant lower limb weakness Gait disturbances Sexual dysfunction

Types of onset

The onset can be either acute or chronic….

Acute onset: of severe back pain, sciatica, urinary disturbances, motor weakness in the lower extremities and saddle anaesthesia or hypoesthesia in patient with no previous history of LBP

More insidious onset characterised by recurrent episodes of backache over a few weeks to years followed by– gradual onset of sciatica and – motor and sensory loss, – with bowel and bladder dysfunction developing over a

few days to several weeks.

Vital questions for patients with LBP ‘Have you noticed any numbness or strange sensations

around your buttocks or between your legs? For example, does the toilet paper feel normal when you wipe your bottom?’

‘Has your bladder been working normally? Can you tell when it’s full? Have you had any loss of control (accidents), or difficulty passing urine? Or have you felt that you want to go all the time?’

‘Have you experienced any unusual problems with your bowels lately?’

‘Have you noticed any changes in sexual function

Physical examination The severity depends on the location and the

degree of compression. The levels most often affected are L4/L5 and L5/S1

Few patients actually present with a ‘classical’ set of signs and symptoms which should be specifically elicited

Neurological examination should include testing for sensation, motor weakness and diminished reflexes

Spinal Stenosis: Pathophysiology

Narrowing of the central canal and/or intervertebral foramina is due to:– Posterior disc bulging – bone spur formation – facet joint enlargement  – hypertrophy of ligamentum flavum

Natural history– Symptoms unchanged in 60-70% – Worse in 15-20% – Improved in 15-20%

Incidence of spinal stenosis on imaging is very high in the elderly population but only a fraction manifest the true symptoms  

Central stenosis:

– increased unsteadiness or loss of balance

– they walk stooped forward 

– Rarely - urinary incontinence & cauda equina syndrome

– Physical examination can be unimpressive

Foramenal stenosis:

– Radicular signs from narrowing of the lateral recess or the neural foramen. 

Discogenic pain

Normal discs have sensory nerve endings in the outer 1/3 of the annulus

Disc stimulation studies normal discs do not cause pain

Disc stimulation is specific for painful discs and is in particular for radial annular tears

Reproduction of pain co-relates with the degree of fissuring of the disc

Spondylo-lysis & listhesis

Caused by a defect in the pars interarticularis Usually a fatigue fracture from repetitive

hyperextension stresses (gymnasts) most common cause of LBP in adolescents plain x-rays demonstrate 80% of lesions oblique views - additional 15% picked up -

'Scottie dog' sign (Lachapelle) CT - may miss fracture

Examination Posture – change in lumbar lordosis, scoliosis Range of motion – flexion,extension, lateral flexion SLR – seated & supine, sciatic nerve stretch test Presence of paraspinal muscle spasm, trigger points Tender areas –facets, sacro-iliac joints Neurological deficit –

– Dermatomal hypo/hyperaesthesia

– Ability to rise from squatting position (L4),walk on heels(L5), walk on tip-toes (S1)

– Tendon reflexes – knee jerk(L4 root), ankle jerk(S1 root)

Evaluation Consider the physical & psychological aspects Degree of interference with desired & necessary

activity Response to past treatments Co-existing complaints & medical diseases Evaluation of functional capacity – walk, stand, sit,

climb stairs

Investigations X-rays:  bone spurs, decreased disc height and facet

hypertrophy in older patients. 

CT: more accurate and detailed picture of the bony anatomy – less accurate than MRI in estimating the degree of

compromise of the soft tissue elements. – thus can underestimate the degree of stenosis – spinal canal < 10mm AP diameter = Absolute Stenosis

MRI: (without gadolinium) – currently represents the "gold standard" in the evaluation of

central stenosis.  – allows visualization of disc, neural elements, ligamentum flavum & thecal sac

Pitfalls Upto 80% of patients cannot be given a definite

diagnosis because of the poor co-relation between symptoms, clinical findings and imaging results

High incidence of false negatives on imaging

No diagnostic lab tests that reveal the cause of LBP

Outcome of treatment difficult to quantify and predict

Management Pharmacological

– NSAIDS – intolerance, cautions, gels, coxibs

– Co-analgesics – TCA, anticonvulsants, ms –relaxants

– Opioids & compound codeine preparations Injection Therapy

– Epidural steroids – lumbar, caudal

– Facet joint injection, Sacro-iliac joint injection, coccyx

– Nerve root infiltration Physiotherapy Acupuncture & TENS Pain management – psychological approaches

Surgical treatment

Urgent operations are required in cases like progressive neural deficit, cauda

equine syndrome, lumbar trauma with instability, tumors and infections (the red flags ) .

The non-urgent operation operation is for persistent pain that does not respond to proper

conservative measures or mechanical LBP with instability

Operative ResultsOperative results can be variable as….. not all stenotic sites necessarily cause symptoms,

therefore selecting decompression levels can be difficult

insufficient decompression regrowth of resected tissue & scarring Multi-level involvement does not do well due to post-op

instability (should consider fusion, but very invasive)

Careful attention to patient selection and meticulous operative planning are important in optimizing surgical outcome.