Lumbar clinical conditions

Question 1

Describe the occurance of mechanical back pain?

Answer 1

50% of the UK population report lumbar back pain for at least 24 hours in any one year

Half of those episodes last > 4 weeks.

80% of the UK population will experience lumbar back pain lasting >24 hours in their lifetime

Question 2

How is mechanical back pain characterised?

Answer 2

Pain when the spine is loaded, that worsens with exercise and is relieved by rest.

It tends to be intermittent and is often triggered by innocuous activity

Question 3

What are the risk factors for mechanical back pain?

Answer 3

Obesity, poor posture, a sedentary lifestyle with deconditioning of the paraspinal (core) muscles, poorly-designed seating and incorrect manual handling (bending and lifting) techniques

Question 4

Describe degenerative changes in the vertebral column which lead to disc degeneration and marginal osteophytosis?

Answer 4

Disk degeneration - Nucleus pulposus of intervertebral disks dehydrates with age. This causes a decrease in the height of the discs, bulging of the discs and alteration of the load stresses on the joints.

Marginal osteophytosis - Osteophytes (bony spurs) called syndesmophytes develop adjacent to the end plates of the discs.

Question 5

How do degenerative changes in the vertebral column lead to osteoarthritic changes?

Answer 5

Increased stress is placed on the facet joints

As the facet joints are innervated by the meningeal branch of the spinal nerve, arthritis in these joints is perceived as painful.

As the disc height decreases and arthritis develops in the facet joints and vertebral bodies, the intervertebral foramina decrease in size.

This can lead to compression of the spinal nerves and is perceived as radicular or nerve pain.

Question 6

What causes slipped disc?

Describe the most common age groups where it occurs?

Answer 6

Pain occurs due to herniated disc material pressing on a spinal nerve.

The most common age group is 30-50 years and 90% of cases resolve by 3 months.

Question 7

What are the four stages of disc herniation?

Answer 7

1. Disc degeneration: chemical changes associated with ageing cause discs to dehydrate and bulge
2. Prolapse: Protrusion of the nucleus pulposus occurs with slight impingement into the spinal canal. The nucleus pulposus is contained within a rim of annulus fibrosus
3. Extrusion: The nucleus pulposus breaks through the annulus fibrosus but is still contained within the disc space
4. Sequestration: The nucleus pulposus separates from the main body of the disc and enters the spinal canal.

Question 8

What are the most common sites for slipped disks?

Why are they the most common?

Answer 8

L4/5 and L5/S1

Due to the mechanical loading at these joints.

Question 9

What is a paracentral prolapse?

Answer 9

Occurs in 96% of cases

The nucleus pulposus most commonly herniates posterolaterally (lateral to the posterior longitudinal ligament), causing compression of a spinal nerve root within the intervertebral foramen

Question 10

State how commonly the different types of disk prolapse occur?

Why is canal filling particulary dangerous?

Answer 10

Paracentral – 96%

Far Lateral – 2%

Canal Filling – 2% - can cause cauda equina syndrome

Question 11

What is sciatica?

Answer 11

The name given to pain caused by irritation or compression of one or more of the nerve roots that contribute to the sciatic nerve (i.e. L4, L5, S1, S2 and S3)

Question 12

Describe the distribution of pain with sciatica?

Answer 12

L4 sciatica: anterior thigh, anterior knee, medial leg

L5 sciatica: lateral thigh, lateral leg, dorsum of foot

S1 sciatica: posterior thigh, posterior leg, heel, sole of foot

Question 13

What causes cauda equina syndrome?

Answer 13

Approx. 5% of cases of cauda equina syndrome are due to a disc prolapse. This most commonly occurs in people aged 30 – 50 years.

Tumours (primary or secondary) affecting the vertebral column or meninges

Spinal infection / abscess

Spinal stenosis secondary to arthritis

Vertebral fracture

Spinal haemorrhage

Late-stage ankylosing spondylitis.

Question 14

What are the 5 red flag symptoms of cauda equina syndrome?

Answer 14

Bilateral sciatica

Perianal numbness (saddle anaesthesia)

Painless retention of urine

Urinary / faecal incontinence

Erectile dysfunction

Question 15

How is cauda equina syndrome treated?

Answer 15

Treated by surgical decompression within 48 hours of the onset of sphincter symptoms, otherwise the prognosis is poor

Question 16

What are the consequences of missing a diagnosis of cauda equina syndrome?

Answer 16

Chronic neuropathic pain

Impotence

Having to perform intermittent self-catheterisation to pass urine

Faecal incontinence or impaction requiring manual evacuation of the rectum

Loss of sensation and lower limb weakness requiring a wheelchair.

Question 17

What is spinal canal stenosis?

Answer 17

Spinal canal stenosis is an abnormal narrowing of the spinal canal that compresses either the spinal cord or the nerve roots

Question 18

What causes spinal canal stenosis?

Answer 18

Tends to affect the elderly.

Due to a combination of:

Disc bulging

Facet joint osteoarthritis

Ligamentum flavum hypertrophy

Other causes include - Compression fractures of the vertebral bodies Spondylolisthesis, Trauma

Question 19

What are the symptoms of spinal stenosis?

Answer 19

Discomfort whilst standing (95% of patients)

Discomfort or pain in the shoulder, arm or hand (for cervical stenosis) or in the lower limb (for lumbar stenosis)

Bilateral symptoms in approximately 70% of patients

Numbness at or below the level of the stenosis

Weakness at or below the level of the stenosis

Neurogenic claudication

Question 20

What is the prognosis of lumbar canal stenosis?

Answer 20

70% of patients’ symptoms stay unchanged, 15% get progressively worse and 15% improve with time.

Question 21

What is neurogenic claudication?

Answer 21

Neurogenic - originates from nerve

Claudication - limp

Symptom rather than a diagnosis.

The patient reports pain and/or pins and needles in the legs on prolonged standing and on walking, radiating in a sciatica distribution

Question 22

What causes neurogenic claudication?

Answer 22

Compression of the spinal nerves as they emerge from the lumbosacral spinal cord.

This leads to venous engorgement of the nerve roots during exercise, leading to reduced arterial inflow and transient arterial ischaemia.

The ischaemia of the affected nerve(s) results in the pain and/or paraesthesia.

Question 23

What is spondylolisthesis?

Answer 23

anterior displacement of the vertebra above on the vertebra below.

Question 24

What is a lumbar puncture?

Answer 24

The withdrawal of fluid from the subarachnoid space of the lumbar cistern. It is an important diagnostic test for a variety of central nervous system disorders including meningitis, multiple sclerosis etc

Question 25

How is a lumbar puncture performed?

Answer 25

Patient lying on the side with the back and hips flexed (knee–chest position).

Flexion of the vertebral column facilitates insertion of the needle by spreading apart the vertebral laminae and spinous processes, stretching the ligamenta flava.

The skin covering the lower lumbar vertebrae is anesthetized, and a lumbar puncture needle is inserted in the midline between the spinous processes of the L3 and L4 (or L4 and L5) vertebrae.

This can be located by finding the plane transecting the highest points of the iliac crests—the supracristal plane—this usually passes through the L4 spinous process.

At these levels, there is no danger of damaging the spinal cord. After passing 4–6 cm in adults (more in obese persons), the needle “pops” through the ligamentum flavum, then punctures the dura and arachnoid, and enters the lumbar cistern. When the stylet is removed, CSF escapes and can be collected.