Week 4 - A - Lumbar Spine - Mechanical back pain, disc tear, sciatica, stenosis, cauda equina, red flags, crush fracture

Question 1

Many people experience back pain at some point during their life and back pain is one of the most common reasons for ill health resulting in time off work. The vast majority of cases will be “mechanical” back pain with no serious underlying pathology. What is the difference between mechanical and inflammatory back pain?

Answer 1

Mechanical back pain is worse with exercise and relieved by rest

Inflammatory back pain is worth with rest and is relieved by exercise

Question 2

Try and describe mechanical back pain in a sentence

Answer 2

Mechanical back pain can be thought of as recurrent relapsing and remitting back pain with no neurological symptoms.

It is worse on movement and relieved by rest

Question 3

Patients with mechanical back pain tend to be between 20 and 60 What are some of the causes of mechanical back pain?

Answer 3

Causes include

* Obesity

* Poor posture

* Poor lifting technique

* Lack of physical activity

* Depression

* Degenerative disc prolapse

* Facet joint OA

* Spondylosis

Question 4

What is spondylosis? What does it lead to?

Answer 4

Spondylosis is a degenerative disorder of the spine where the intervertebral discs lose water content with age

This results in less cushioning and increased pressure on the facet joints leading to secondary OA and the development of oteophytes

Question 5

What is the treatment of mechanical back pain? What should you tell the patients?

Answer 5

Mechanical back pain is treated with analgesia and physiotherapy

Patients should be reassured that they do not have a serious problem and should be urged to maintain normal function and return to work early

Question 6

Acute inter-vertebral disc tears

* What are the two parts of the intervertebral disc? * Which part do the disc tears usually occur in?

Answer 6

Intervetebral disc consists of the inner gelatinous nucleus pulposus and the outer tough annulus fibrosus

Disc tears usually occur in the outer annulus fibrosus (this can allow herniation of the nucleus pulposus)

Question 7

What is the usual cause of an acute disc tear?

Answer 7

Acute disc tears classicially happen after lifting a heavy object eg a lawnmower

Question 8

What is the presenting symptom of acute disc tears? - when is it worse?

Answer 8

Acute disc tears can be very painful and severe as the periphery of the disc, the annulus fibrosus is richly innervated

Pain is characteristically worse on coughing (which increases disc pressure)

Question 9

What is the treatment of acute disc tears? How long can they take to settle?

Answer 9

Like mechanical back pain, treatment is usually analgesia and physiotherapy

Symptoms usually resolve but can take 2-3 months to settle

Question 10

When a disc tear occurs, what can herniate or prolapse through the tear? What can herniation of this cause to the spinal cord / nerves?

Answer 10

If an acute disc tear occurs, the gelatinous nucleus pulposus can herniate through the tear

Usually herniating discs protrude do not impinge directly onto the spinal cord (due to posterior longitudinal ligament)

* The herniating disc can impinge on an exiting nerve root however

Question 11

What is the presentation of a herniated disc? What is the commonest site for disc herniation to occur?

Answer 11

Presentation usually results in pain and altered sensation in a dermatomal distribution as well as reduced power in a myotomal distribution

Reflexes may also be reduces (these are all signs of a LMN lesion which it is)

Commonest site for a disc herniation is

* L4/5 and L5/S1 intervertebral disc levels

Question 12

The commonest site for this to occur in the spine is the lower lumbar spine with the L4, L5 and S1 nerve roots contributing to the sciatic nerve and pain radiating to the part of the sensory distribution of the sciatic nerve (hence the term “sciatica”). How would you describe the pain in sciatica?

Answer 12

The pain in sciatic would be described as a radicular pain - type of pain radiating into the lower extremity directly along the course of a spinal nerve

The radicular pain feels like a burning or severe tingling pain (neuralgic pain) often like severe toothache

Question 13

Where in the lower limb is the burning / severe tingling pain felt in sciatic? How does this differenitiate it from back pain?

Answer 13

The neuralgic burning / severe tingling pain radiates down the back of the thigh and below the knee (remember sciatic nerve innervation)

This differentiates the pain from mechanical back pain as this can radiate to the buttock and thigh but not below the knee

Question 14

How do you test for sciatica? Test name and how it is carried out?

Answer 14

Test for sciatica with the sciatic stretch test

* In this test, perform a straight leg raise - pain may be felt due to impinging of the sciatic nerve

* To make the test more specific, then dorsfilex the toe and note additional pain

Question 15

Usually in the lumbar spine, the nerve root corresponding to the lower of the two vertebra in the affected segment is compressed State the nerve entrapped and the symptoms (dermatome, myotome) in a * L3/4 prolapse * L4/5 prolapse * L5/S1 prolapse

Answer 15

* L3/L4 prolapse - L4 root entrapment - pain down to medial ankle, loss of quadriceps power and reduced knee jerk

* L4/L5 prolapse - L5 root entrapement - pain down dorsum of foot, reduced power of extensor hallucis longus and tibialis anterior

* L5/S1 prolapse - S1 root entrapment - pain to sole of foot, reduced power plantarflexion and reduced ankle jerk

Question 16

The nerve affected by the disc prolapse really depends on how lateral the disc herniation is Say for each of the pictures the black spot is in L4/5 intervetebral disc space State which nerve is affected in each picture? What is the most common example?

Answer 16

• Type A - lateral herniation affecting the L4 exiting nerve root
• Type B - more central herniation affecting the L5 traversing nerve root- most common herniation
• Type C - central herniation leading to cauda equina
• Type D - formation of osteophytes in lateral canal will cause L5 root compression (spondylosis)

Question 17

What is the first line treatment of sciatica?

Answer 17

Fist line treatment is analgesia, maintaining mobility and phsyiotherapy

Question 18

What drug may be of benefit in sciatic if the leg pain is particular severe? When is surgery (discectomy indicated)?

Answer 18

Neuropathic pain drugs eg gabapentin or pregablin can be used if leg pain is particularly severe

Very occasionally (discectomy) is indicated

* when the pain is not resolving despite physiotherapy

* and there are localising signs suggesting a specific nerve root involvement

* and positive MRI evidence of nerve root compression

Question 19

OA of the facet joints can result in osteophytes impinging on exiting nerve roots, resulting in nerve root symptoms and sciatica as previously discussed. What can be done as treatment here?

Answer 19

Surgical decompression with trimming of osteophytes

Question 20

What is the general definition of spinal stenosis? Is lumbar or cervical spine stenosis more common?

Answer 20

The general definition of stenosis is the abnormal narrowing of a passageway in the body

Lumbar stenosis is more common than cervical spine stenosis

Question 21

With spondylosis and a combination of bulging discs, bulging ligamentum flavum and osteophytosis, the cauda equina of the lumbar spine has less space What is this condition known as? What else can be comrpessed?

Answer 21

This condition is known as spinal stenosis where spinal cord and multiple nerve roots can be compressed / irritated

Question 22

What age group does spinal stenosis tend to have affect? and when is pain characteristically felt?

Answer 22

Spinal stenosis tends to affect over 60s and characteristically have claudication (pain in the legs on walking)

Question 23

How does the claudication in spinal stenosis differ from the vascular claudication seen in peripheral vascular disease?

Answer 23

In contrast to vascular claudication (PVD), spinal stenosis presents with

* Claudication distance being inconsistent

* Pain is burning rather than cramping

* Pain is less walking uphill (spine flexion creates more space for cauda equina)

* Pedal pulses are preserved

Question 24

What is the management of spinal stenosis? What happens if first line management fails?

Answer 24

Conservative management is first line with physiotherapy and weight loss if indicated

If there is MRI evidence of stenosis and conservative management fails, surgery may be performed (decompression to increase space for cauda equina)

Question 25

Occasionally a very large central disc prolapse can compress all the nerve roots of the cauda equina producing a clinical picture known as what? Is this a surgical emergency?

Answer 25

Cauda equina syndrome can occur occassionally when a very large central disc prolapse compresses all the nerve roots of the cauda equina

THIS IS A SURGICAL EMERGENCY

Question 26

What are the presenting features of cauda equina syndrome?

Answer 26

* Saddle anaesthesia - numbness around the sitting area and perineum

* Bilateral leg pain, paraesthesia (weakness) or numbness

* Altered bladder or bowel function

In essence, any patient with bilateral leg symptoms/signs with any suggestion of altered bladder or bowel function is a cauda equina syndrome until proven otherwise.

Question 27

If cauda equina syndrome is not treated immediately, what can happen?

Answer 27

Prolonged compression can cause permanent nerve damage requiring colostomy and urinary diversion - urgent treatment can prevent this catastrophe

Question 28

What is the mandatory first line examination to carry out in cauda equina syndrome? What may it reveal? What investigation is done urgently to determine the level of the prolapse?

Answer 28

Mandatory first line investigation is a digital rectal examination (DRE) - assesses for loss of anal tone and sensation

Urgent MRI is required to determine the level of prolapse

Question 29

What is required once the diagnosis and level of disc prolapse have been confirmed in cauda equina?

Answer 29

Urgent discectomy is required to decompress the spinal cord once diagnosis is confirmed

Even with prompt surgical intervention, significant number of patients have residual nerve injury with permanent bladder and bowel dysfunction.

Question 30

Clinical evidence of cauda equina syndrome is one of the red flags for serious spinal disease. You will hear the term “red flag” symptoms or signs when spinal conditions are discussed. The presence of such symptoms may indicate that significant and serious underlying pathology is present, such as tumour, infection or spondylolisthesis What are 4 main red flags symptoms?

Answer 30

Back pain in the younger patient ( 60 years)

Nature of pain - constant, severe, worse at night

Systemic upset - fevers, night sweats, weight loss, fatigue, malaise

Question 31

Significant back pain in childhood, adolescence or early adulthood is uncommon. What are younger children more susceptible to? What are adolescents at peak age for?

Answer 31

Younger children are more susceptible to infections - osteomyelitis and discitis

Adolescents are the peak age for spndylolisthesis as well as some benign (osteoid osteoma) and malignant (osteosarcoma) primary bone tumours

Question 32

New back pain in patients older than 60 years brings worry of what?

Answer 32

Back pain in the older patient may represent arthritic change or a crush fracture

However patients in this age group are at higher risk of neoplasia, particularly metastatic disease and multiple myeloma.

Question 33

In patients with a red flag of constant, severe pain that is worse at night, what is the worrying caise?

Answer 33

Pain from tumour or infection tends to be constant, unremitting, severe and worse at night.

Mechanical back pain is worse with activity and tends to be relieved by rest.

Question 34

What is important to consider in a patient presenting with back pain and the red flag of systemic upset?

Answer 34

Back pain with Fevers, night sweats, weight loss, fatigue and malaise may indicate the presence of underlying tumour or infection.

Question 35

A spinal fracture due to osteoporosis (weak bones) is commonly referred to as a compression fracture Wedge fractures are the most common type of compression fractrue where the front of the veretebral body collaspes making a wedge shape What are crush fractures and when do they occur?

Answer 35

Crush fractures are when the entire vertebral bone breaks rather than just the front of the vertebra - they can occur with severe osteoporosis (The burst fractures are usually in young related to high-energy axial loading spinal trauma)

Question 36

How can crush fractures present? What is the usual treatment for crush fractures?

Answer 36

Crush fractures may present with acute pain and kyphosis

They are usually treated conservatively -analgesics and physiotherapy