13 – Low back pain

Basics of spine

• Intervertebral discs
  • They lie between the vertebral bodies
  • They consist of the outer annulus fibrosus and the inner nucleus pulposus
  • The discs have no blood supply, they’re instead supplied by diffusion
    • Moving of the spine causes changes in compression of the discs, which creates a “pumping” effect which facilitates diffusion of nutrients
  • Annulus fibrosus
    • = concentric collagen fibres
    • Protects against distraction
  • Nucleus pulposus
    • Gelatinous core
    • Consists of mostly water
    • Protects against compression
  • As the patient ages the water content of the discs decreases, which puts more of the compression forces on the vertebral bodies

20. Spondylolysis, spondylolisthesis, sacralisation, lumbarization

Spondylolysis

• Spondylolysis is a defect of the neural arch (pars interarticularis) of the vertebrae which allows the vertebra lying superiorly to slip anteriorly, called spondylolisthesis
• More common in certain territories
• Diagnosis: oblique x-ray
• Most commonly between L5-S1

Spondylolisthesis

• Spondylolisthesis refers to anterior slipping of a vertebra compared to the one below it
• Etiology
  • Spondylolysis
  • Fracture
  • Congenital malformation
  • Tumour
• Clinical features
  • Many cases are asymptomatic
  • Low back pain
  • Palpable “step off” at the area of slippage
  • Pain may radiate
• Severe (grave V) spondylolisthesis is called spondyloptosis
  • The vertebra has slipped so far with respect to the vertebra below that the two endplates are no longer congruent

Sacralisation and lumbarisation

• Sacralisation = fusion of L5 to S1
• Lumbarisation = non-fusion of S1 and S2, which causes the S1 to appear as a sixth lumbar vertebra
• These are congenital abnormalities
• Due to abnormal weight bearing -> problems with the rest of the spine
• May cause lumbago in adult years

29. Spondylarthritis ankylopoetica (ankylosing spondylitis)

• Ankylosing spondylitis is an inflammatory disorder of the back. It's also called Bektherev disease
• Epidemiology
  • Males > females
  • 15 – 40
• Etiology
  • HLA-B27 positivity
  • Inflammatory bowel disease
• Pathology
  • Ankylosis = fusion of articular surfaces
  • Spondylitis = inflammation of the vertebrae
• Clinical features
  • Back pain
  • Neck pain
  • Morning stiffness
  • Limited spinal mobility
  • Anterior uveitis
• Diagnosis
  • Schober test
  • X-ray
    • Shows ankylosis and sacroilitis
• Treatment
  • Conservative
    • Physical therapy
    • NSAIDs
    • Biological therapy (TNF inhibitors)
  • Surgery
    • Osteotomy
    • Nerve decompression
    • Spinal fusion

36. The degenerative spine (spondylosis, low back pain)

Spondylosis is an age-related degenerative change in spinal vertebrae. It's most commonly due to spinal osteoarthritis. It may cause compression of the spinal cord, causing low back pain or sciatica.

Low back pain

• Low back pain is very common
• LBP can generally take on one of two major forms
  • Lumbago (mechanical low back pain)
  • Sciatica (neurological low back pain)
• LBP can occur in a healthy spine, often due to stretching or microscopic tears of muscles or ligaments

• Lumbago
  • = mechanical low back pain
  • (Some sources, like this year’s lecture, reserve the term “lumbago” for idiopathic LBP)
  • Can have many causes
    • Mechanical disorders
    • Congenital malformations
    • Lumbar instability
    • Degenerative diseases
  • Can be acute or chronic
    • Lasts less than 1 month – acute
    • Lasts more than 6 months – chronic
  • Clinical features
    • Low back pain
    • Decreased lumbar lordosis
    • Antalgic gait
    • Paravertebral muscle spasm
    • Restricted lumbar movements
    • No neurological signs (radiation, paraesthesia, etc.)
  • Treatment
    • Analgesia
    • For acute lumbago – rest
    • For chronic lumbago – mobilization
    • Surgery is almost never indicated

66. Discus hernia, sciatica

Sciatica

Sciatica, also called ischias syndrome or lumboischialgia (the latter usually in Hungarian literature), refers to a type of low back pain which is neurological in nature and radiates to the legs below the knees. It occurs due to compression of spinal roots, most frequently due to spinal disc herniation.

Clinical features

• Low back pain
• Decreased lumbar lordosis
• Antalgic gait
• Paravertebral muscle spasm
• Restricted lumbar movements
• Neurological symptoms (usually follow L5/S1 distribution)
  • Pain radiating to the legs
  • Paraesthesia in the legs

Spinal disc herniation

Spinal disc herniation, also called disc extrusion, refers to when the nucleus pulposus extrudes out of the disc through a tear in the annulus fibrosus, which compresses spinal nerves or spinal cord.

Spinal disc protrusion, also called disc prolapse, refers to a similar situation where the intervertebral disc protrudes onto spinal nerves or the spinal cord but the nucleus has not broken through the annulus. The protruding disc may still compress nerves.

Spinal disc sequestration is similar to herniation but part of the nucleus pulposus has torn off and has been left as a fragment.

Compression of spinal nerves or spinal cord can cause sciatica, cauda equina syndrome, or conus medullaris syndrome.

Clinical features

The most common symptom is sciatia (pain in the distribution of one of the below mentioned spinal nerves), but it can also cause loss of muscle function or paraesthesia.

• L4
  • Motor: Tibialis anterior muscle
  • Reflex: Patellar reflex
  • Sensory: Medial part of feet
• L5
  • Motor: Extensor hallucis longus muscle
  • Reflex: Ankle reflex
  • Sensory: Middle part of feet
• S1
  • Motor: Peroneus muscle
  • Reflex: Achilles reflex
  • Sensory: Lateral part of feet

Diagnosis and evaluation

• Physical examination
• Straight leg-raise test (Lasegue test)
• MRI
  • Gold standard

Treatment

• Most cases are self-limiting, healing itself
• Conservative
  • Physiotherapy
  • Local heat
  • NSAIDs
• Herniectomy or discectomy
  • If conservative treatment fails or in case of cauda equina syndrome

Cauda equina syndrome and conus medullaris syndrome

Cauda equina syndrome is a consequence of compression of the cauda equina, the nerve fibres of L3 – S5. Conus medullaris syndrome is a consequence of compression of the conus medullaris, the spinal cord segments T12 – L2. Both are neurological emergencies as they may cause permanent neurological injury if untreated. They are usually caused by spinal disc herniation.

These syndromes are medical emergencies and so any patient with these signs must undergo imaging and decompressive surgery immediately. Urgent neurosurgery to decompress the spine is necessary.

Warning signs

• Saddle anaesthesia
• Paraplaegia
• Urinary retention or incontinence
• Loss of lower extremity reflexes

These signs are suspicious for spinal cord compression, conus medullaris syndrome or cauda equina syndrome.

Clinical features

Conus medullaris syndrome	Cauda equina syndrome
An upper motor neuron lesion	A lower motor neuron lesion
Symmetric symptoms	Asymmetric symptoms
Motor symptoms rare	Paraparesis and loss of patellar and Achilles reflex
Sensory loss of pelvic and perianal region (saddle anaesthesia)
No pain	Radicular pain
Vegetative symptoms like urinary retention, faecal incontinence, erectile dysfunction, loss of anal and bulbocavernosus reflexes