Orthopaedics - Spine

Question 1

How many vertebrae make up the cervical, thoracic, lumbar and sacral segments?

Answer 1

7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
5 sacral vertebrae

The sacral vertebrae are fused to form a solid mass.

Question 2

Describe the main characteristics of a vertebra? What processes are given off by the vertebral arch?

Answer 2

The vertebra in each section of the spine have different characteristics, but they all share some common features.

Anteriorly is the vertebral body. Posteriorly, the vertebral arch encloses the spinal canal in which lies the spinal cord. The vertebral arch consists of 2 pedicles which arise from the vertebral body and two flattened laminae that come together to form the posterior wall of the arch.

The vertebral arch gives off a spinous process posteriorly, two transverse processes laterally and four articular processes - two superior and two inferior. The articular processes articulate with the corresponding processes of the vertebra above and below to form facet joints.

Question 3

What are the anatomical features of cervical vertebrae?

Answer 3

Cervical vertebrae are:

• small
• transverse foramina (for passage of vertebral artery)
• rudimentary transverse processes
• flat facet joints

Question 4

Anatomical features of thoracic vertebrae?

Answer 4

Thoracic vertebrae are:

• large in size
• larger transverse processes that articulate with the ribs
• heart shaped spinal canal
• oblique facets (causing a natural lordosis)

Question 5

Anatomical features of lumbar vertebrae?

Answer 5

Lumbar vertebrae are:

• the largest vertebrae
• stout transverse processes
• almost vertical facet joints

Question 6

Describe the structure of the intervertebral disc?

Answer 6

The IVDs are located between adjacent vertebral bodies. They allow movement between vertebral bodies and act as shock absorbers.

They have a tough, outer fibrocartilagenous annulus fibrosus surrounding a central nucleus pulposus made of water and cartilage.

As an individual gets older, the fibres of the annulus degenerate and weaken. Excessive loading of the disc may result in rupture of the annulus and herniation of the nucleus pulposus. This may press on the nerve root or the spinal cord.

Question 7

What are the 3 main groups of ligaments that connect vertebrae to one another?

Answer 7

1) Anterior longitudinal ligament - runs as a continuous band along the anterior aspect of the vertebral bodies from skull to sacrum
2) Posterior longitudinal ligament - a band connecting the posterior aspects of the vertebral bodies. It is not as strong as the anterior longitudinal ligament but is important because it forms the anterior boundary of the spinal canal
3) Interspinous ligaments - run between adjacent spinous processes and prevent excessive forward flexion of the spine

Question 8

How should the neck be examined?

Answer 8

The posture of the neck and any bone tenderness (midline and over the spinous processes) are noted.

Most neck examination is performed in the context of suspect cervical spine injury, so the patient is likely to be immobilised with collar and blocks. If these are safe to remove, check the range of movements: flexion and extension (mainly atlanto-occipital joint), rotation (mainly atlanto-axial joint) and lateral flexion (whole of the cervical spine). Rotation is the movement most commonly affected.

Examine the arms and test for root lesions and reflexes (biceps C5, brachioradialis C6, triceps C7). If cord compression is suspected, examine the lower limbs for signs of this - e.g. hyperreflexia and upgoing plantars.

The main sites of injury are C6 and 7, followed by C2. Roughly 10% of C spine fractures will have another spine fracture eleswhere, so always examine the whole spine!

Question 9

What is cervical spondylosis?

Answer 9

This refers to degenerative changes of the cervical spine - e.g. degeneration of the annulus fibrosis and bony spurs narrow the spinal canal and intervertebral foramina.

It is extremely common, 90% of men >60 years and women over 50 years exhibit some degree of degeneration. However, it is usually asymptomatic, but can cause neck and arm pain with parasthesia - sometimes with myelopathy (spastic weakness and later, incontinence).

Question 10

What is mechanical back pain?

Answer 10

Soft tissue injury leads to dysfunction of the whole spine causing muscle spasm and pain.
It may have a precipitating event, e.g. lifting.
Typically happens in younger patients with no sinister features (e.g. weight loss, night sweats etc)

Question 11

How is mechanical back pain managed?

Answer 11

Conservative:

• Max 2d bed rest
• Education: keep active, how to lift/ stoop
• Physiotherapy
• Warmth - e.g. swimming in a warm pool

Medical:

• analgesia: paracetamol +/- NSAIDS +/- codeine
• muscle relaxant: low dose diazepam (short term)

Question 12

What back pain diagnoses should not be missed?

Answer 12

Infection - discitis or epidural abscess
Fracture
Malignancy - primary or metastatic
Inflammatory conditions - ankylosing spondylitis
Nerve root impingement or cauda equina syndrome

Question 13

What are the red flag signs for back pain?

Answer 13

Thoracic pain
Fever
Unexpected weight loss 
History of cancer 
Age of onset <20 or >55 years
Pain worse at night 
Neurological deficit - e.g foot drop
Saddle anaesthesia and loss of bladder control

Question 14

What causes disc herniation?

Answer 14

The vertebrae are separated by intervertebral discs, composed of two parts. The outer fibrous annulus fibrosus and the inner nucleus pulposus.

As part of the natural ageing process, the nucleus pulposus becomes dehydrated and brittle. This is a common cause of mechanical back pain. The annulus fibrosus may also be affected and may split, allowing the nucleus pulposus to leak out.

Question 15

How do patients present with disc herniation?

Answer 15

If a disc herniation compresses a nerve root, the result is shooting pain, numbness and weakness in the distribution of the affected nerve. This is known as a radiculopathy. The commonest nerve roots to be affected are those supplying the sciatic nerve (L4-S3) causing sciatica. Typically, sciatica pain radiates from the buttock as far as the sole of the foot. The exact presentation depends on the nerve root affected.

Question 16

How does an L3 nerve root compression present?

Answer 16

Sensory loss over the anterior thigh
Weak quadriceps
Reduced knee reflex (“L3, L4 kick the door”)
Positive femoral stretch test

Question 17

What are the features of an L4 nerve root compression?

Answer 17

Sensory loss over the anterior aspect of the knee
Weak quadriceps
Reduced knee reflex
Positive femoral stretch test

Question 18

How does an L5 nerve root compression present?

Answer 18

Sensory loss over the dorsum of the foot
Weakness in foot and big toe dorsiflexion
Reflexes intact
Positive sciatic nerve stretch test

Question 19

How does an S1 nerve compression present?

Answer 19

Sensory loss posterolateral aspect of the leg and lateral aspect of the foot
Weakness in plantar flexion
Reduced ankle reflex
Positive sciatic nerve stretch test

Question 20

How should disc prolapse be managed?

Answer 20

The patient should be carefully examined for evidence of cauda equina syndrome. If neurology is progressive, or symptoms have been present for more than 6 weeks, an MRI should be organised. Most cases will settle with conservative treatment as the herniated nucleus pulposus is resorbed and inflammation settles. Symptoms lasting more than 3 months are unlikely to resolve spontaneously and surgery to remove the herniated disc, discectomy, may be considered.

Question 21

What is cauda equina syndrome?

Answer 21

The spinal cord terminates in an adult at L1. Below this level, the spinal canal is occupied by lower motor nerves, collectively known as the cauda equina (horses tail). The nerve roots are L2-S4 and supply most of the lower limb muscles and sensation of the perineum, including the bladder and rectal sphincters.

A large disc herniation (or mass) can compress the nerves of the cauda equina. This is cauda equina syndrome and is a surgical emergency.

Question 22

What are the signs and symptoms of cauda equina syndrome?

Answer 22

Symptoms and signs include back pain, lower limb flaccid paralysis, loss of reflexes, paraesthesia of the perineum, loss of anal tone, faecal incontinence, painless retention of urine, overflow or stress incontinence of urine. Not all of these may be present.

Perform a full neurological exam as well as a rectal exam. If the patient is in retention, catheterise and note the residual volume in the bladder and whether the patient felt the catheter being inserted.

Question 23

What are the MRI features of disc herniation?

Answer 23

A T2 weighted image shows the CSF as bright. The nucleus pulposus of the discs can be dark which indicates dehydration. Disc herniation shows as a narrowing of of the spinal canal.

Question 24

How is cauda equina syndrome managed?

Answer 24

Treatment should be performed urgently and consists of surgical decompression of the spinal canal and evacuation of the herniated disc. Delaying surgery more than 24 hours significantly increases the risk of developing permanent nerve damage.

Question 25

What is spinal stenosis?

Answer 25

In the elderly, a combination of disc degeneration and arthritis of the facet joints at the back of the spine can result in narrowing of the spinal canal, putting pressure on the spinal cord. The result is chronic leg pain, worse when walking and standing and relieved by leaning or sitting forwards. It resembles vascular claudication and may be differentiated by a normal vascular exam and a careful history. Patients often notice that there exercise tolerance improves when walking around a supermarket - they are in fact opening up the spinal canal by leaning forward on the shopping trolley!

Question 26

How is spinal stenosis treated?

Answer 26

Treatment includes steroid epidural injections to reduce swelling, or surgical decompression of the canal (laminectomy).

Question 27

What is discitis?

Answer 27

A serious cause of back pain, discitis is infection within the intervertebral disc. The slow rate of blood flow within the disc allows bacteria from remote sources to become lodged and multiply. The result is severe back pain, fever and raised inflammatory markers. The elderly and immunosuppressed are most at risk. If left untreated it can lead to an epidural abscess. This forms within and can compress the spinal canal.

Question 28

How should discitis be investigated? How is it treated?

Answer 28

Investigations include inflammatory markers, blood cultures, MRI of the spine and search for the source of bacteraemia, including cardiac echo to look for vegetations. Treatment is a protracted course of antibiotics, often for several months. Presence of neurological symptoms may require surgical decompression.

Question 29

What tumours commonly metastasise to the spine?

Answer 29

Multiple myeloma is neoplasm of plasma (antibody producing) cells and has a preference for the spine. Other common metastases are breast, prostate, lung, thyroid and kidney.

Patients may present with weight loss, general malaise and pain worse at night as well as symptoms of the primary tumour. A high index of suspicion is needed. Investigations include MRI, CT of the chest, abdo pelvis, urinary Bence Jones proteins and tumour markers.

Question 30

What is ankylosing spondylitis?

Answer 30

AS is one of the seronegative arthropathies and is a chronic inflammatory disorder affecting the axial skeleton.

Sacro-ilitis is usually visible on plain film x ray. Up to 20% of patients who are HLA-B27 positive will develop the condition.

Affected articulations develop bony or fibrous change. Typical spinal features include loss of the lumbar lordosis and progressive kyphosis of the cervico-thoracic spine.

Question 31

How should ankylosing spondylitis be investigated?

Answer 31

Inflammatory markers (ESR, CRP) are raised, but normal levels should not exclude the diagnosis.

HLA-B27 is of little value in making the diagnosis as it is:

• positive in 90% of patients with ankylosing spondylitis
• positive in 10% of the normal population

Plain x ray of the sacro-iliac joints is the most useful investigation. Radiographs may be normal in early disease but later changes include:

• bamboo spine (late and uncommon)
• syndesmophytes: due to ossification of the outer fibres of the annulus fibrosus
• squaring of lumbar vertebrae
• Dagger sign (single central radiodense line related to ossification of the suprapsinous and interspinous ligaments)

Question 32

What is Scheuermman’s disease?

Answer 32

The main pathological process is epiphysitis of the vertebral joints.
It predominantly affects adolescents.
Symptoms include back pain and stiffness.
X ray findings include epiphyseal plate disturbance and anterior wedging.
Clinical features include progressive kyphosis.
Minor cases may be managed by physiotherapy and NSAIDs. Major cases may require bracing or surgical stabilisation.

Question 33

What are the examination features of ankylosing spondylitis?

Answer 33

Reduced lateral flexion.
Loss of lumbar lordosis.
Reduced forward flexion - Schober’s test; a line draw 5cm below and 10cm above the back dimples (dimples of Venus). The distance between the two lines should increase by more than 5 cm bends forwards as far as possible.
Reduced chest expansion.

Question 34

What is congenital scoliosis?

Answer 34

This happens when there is failure of adjacent vertebra to separate, or failure of half a vertebra to grow, results in a mismatch between left and right halves of the spine. The result is a rapidly progressive scoliosis of the spine in infants.

Congenital scoliosis is often associated with other congenital abnormalities affecting the heart, renal, genitourinary and facial abnormalities. In addition, restriction of the thoracic cavity at an early age limits development of the lungs.

Surgery is difficult and dangerous with risk of neurological injury and short stature as an adult.

Question 35

What is scoliosis?

Answer 35

Scoliosis is deformity of the spine in three planes - rotation, lateral bending and lordosis. In mild cases it may be barely noticeable. In moderate cases, predominance of the ribs on one side produces cosmetic concerns. In severe cases, pulmonary insufficiency results from restriction of thoracic expansion. Scoliosis can be classified into several groups:

• idiopathic
• congenital
• neuromuscular

Question 36

What is neuromuscular scoliosis?

Answer 36

Conditions that alter the normal tone of muscles can result in scoliosis in the growing child. Underlying conditions may be paralytic (e.g. polio), muscle weakness (e.g. muscular dystrophy), or upper motor neurone (e.g. cerebral palsy). The curves tend to be long and C shaped involving both lumbar and thoracic segments. Treatments may include bracing, adapting wheelchair cushions to allow sitting, or surgical correction.

Question 37

What is idiopathic scoliosis?

Answer 37

This is the commonest type of scoliosis. It may occur as an infant (<3 years), juvenille (3-10 years) or an adolescent (>10 years). The curve may be single (lumbar or thoracic) or double involving both lumbar and thoracic segments. The commonest type is adolescent idiopathic scoliosis with a RIGHT thoracic curve.

Question 38

How is idiopathic scoliosis diagnosed?

Answer 38

The child or a parent may notice one shoulder blade is more prominent than the other, or the shoulders or hips appear at different levels. The child may compensate very effectively for a thoracic curve by bending the lumbar spine to stay upright. In order to eliminate this compensation, perform the Adams’ forward bend test: ask the child to bend at the waist and look from behind at the level of the scapula. The alternative is to sit the child down with his hips bent at 90 degrees. This eliminates the lumbar compensation.

Question 39

How is idiopathic scoliosis treated?

Answer 39

As a rule of thumb, the treatment of idiopathic scoliosis depends on the Cobb angle. Treatment should be:

• <25 = observe
• 25-40 = brace
• > 40 = consider surgery

Question 40

How is the curve magnitude measured?

Answer 40

X rays are the first investigation for scoliosis. The whole spine should be imaged on a PA film.
Draw a plumb line from C7 to the middle of the sacrum. This represents the midline. Try to identify where the curve starts and ends: the disc spaces will be open on one side and closed on another. The point at which the disc orientation changes is the end vertebra. Next measure the Cobb angle between the two end vertebrae. This parameter defines the magnitude of the curve.

Question 41

What factors suggest a curve will progress?

Answer 41

Some curves will not progress and can therefore be treated conservatively. Others will progress rapidly and may need treatment with a brace or surgery. There are several risk factors that can predict progression. The important risk factors are:

• female sex
• young age
• premenarche
• skeletal immaturity
• Cobb angle >50 degrees
• Progression of >5 degrees over two serial X rays

Question 42

What is Spondylolysis?

Answer 42

This is a defect in the pars interarticularis - the section of bone between the superior and inferior parts of the facet joint. There are a number of reasons why a defect may be present in adults, but in adolescents the commonest reason is stress fracture due to repeated hyperextension. Sportsman and gymnasts are typically affected, complaining of lower back pain.

X ray may show a fracture, although it can be difficult to see. Oblique X rays may be helpful. Better is a CT or SPECT (a technique that combines a CT with a bone scan).

Question 43

How is spondylolysis managed?

Answer 43

Mild cases resolve with activity modification. More severe cases, where the fracture has displaced, may result in spondylolisthesis - forward slippage of a lumbar vertebra over another. If this occurs, reduction and fixation may be required.

Question 44

What is spina bifida?

Answer 44

This is caused by non fusion of the vertebral arch during embryonic development. There are three categories: meningocele, spina bifida occulta and myelomeningocele.

Myelomeningocele is the most severe type with persistence of neurological defects in spite of anatomical closure of the defect.

Up to 10% of the population may have spina bifida occulata, in this condition the skin and tissues (but not bones) may develop over the distal cord. The site may be identifiable by a birth mark of hair patch.

Incidence has decreased since folic acid supplementation was introduced for pregnant women.