Back pain and nerve entrapment syndromes

Question 1

Function of a healthy intervertebral disc

Answer 1

• Shock absorber
• Allow movement
• Transfer weight

Question 2

Describe structure of healthy intervertebral disc

Answer 2

• Annulus fibrosis: Tough elastic ring that ties vertebrae together
• Nucleus Pulposus: Semi-fluid gelatinous filling inside annulus fibrosis
• Vertebral endplate: cartilage plates on vertebral body surface

Question 3

List the types of back pain

Answer 3

Somatic referred pain:

• The site of injury of pain is distant from the location where the pain is felt. e.g. pain from compression of nerve in arm is felt at the hand
• Pain is referred from a superficial or deep structure

Radicular pain:

• Pain originates at the spinal root and relates to nerve root irritation
• Characterized by shooting and burning pain.

Question 4

List the causes of back pain

Answer 4

<1%: serious spinal pathology:

• Malignancy
• Spinal infection
• Vertebral fracture

5-10%: Radicular syndrome:

• Radicular pain
• Spinal stenosis (narrowing of spinal column)

90-95%: Non-specific lower back pain

• Muscle sprain
• Muscle spasm
• Ligament sprain
• Minor vertebral joint problem

Question 5

Define and describe ankylosing spondylitis

Answer 5

• Long term inflammation of joints of spine causes vertebral arthritis
• Onset: age <40, gradual
• Symptoms:
  1) buttock pain
  2) pain at night (relieved in morning)
  3) Fatigue
  4) Weight loss

Question 6

Describe disc degeneration consequences and causes

Answer 6

• Intervertebral disc ruptures or herniates due to wear from movement
• Degeneration occurs in areas of highest mobility (e.g. cervical and lumbar regions)

Question 7

Describe disc prolapse causes and consequences

Answer 7

• Ligaments support ventral bodies anterolaterally and posteriorly
• Annulus rupture herniates between ligaments (i.e. towards intervertebral foramen).
• Exiting nerve of spinal nerve of lower vertebrae is compressed: e.g. if herniation of L5-S1 disc, sacral nerve S1 would be compressed

Question 8

Relate the developmental aspects of the spinal cord to the clinical problems associated with compression of the sciatic nerve

Answer 8

Development of spinal cord:

• Spinal column and spinal cord same length in early embryo
• Spinal column elongates much faster
• Spinal cord ends at L1 or L2 in adults
• Lower spinal cords form a ‘horse’s tail’ where spinal nerves leave spinal cord in vertebral column and travel inferiorly before exiting vertebral column

Question 9

Discuss spinal nerves in relation to developmental aspects

Answer 9

• In embryo, each afferent and efferent nerves supply dermatomes and myotomes respectively
• In adults, ventral rami of spinal nerves form plexus:
• C1-C4 = Cervical plexus to neck
• C5-T1 = Brachial plexus to arm
• T2-T12 = no plexus (intercostal nerves)
• L1-L4 = lumbar plexus to pelvis
• L5-S4 = Sacral plexus

Question 10

Describe sciatica

Answer 10

• Sciatica = pain due to injury of sciatic nerve or compression of ventral rami of L4 to S3
• Commonly caused by herniation of L5-S1 disc
• Causes tingling and numbness, leading to wasting of muscles supplied by sciatic nerve (legs)

Question 11

Describe the range of back and other musculoskeletal disorders seen in dentists and members of the dental team

Answer 11

Carpal Tunnel Syndrome
- Caused by entrapment of medial nerve
- Leads to paranesthesia of hand
 Risk factors:
- Female
- Menopause
- Obesity/lack of fitness
- Diabetes/family history of diabetes
- Osteoarthritis of metacarpophalangeal joint of thumb
- Smoking
- Alcohol
- Occupation with repetitive movement tasks

Question 12

Outline approaches to treatment and management of back pain and nerve entrapment syndromes

Answer 12

Treatment of back pain:
- Rehabilitation - most effective treatment of lower back pain: strength training, flexibility fitness, aerobic training

• Treat significant underlying illness (rare 5%)
• Bed rest discouraged