S2 - Cervical, Thoracic Spine Conditions Flashcards
- *Mechanical back pain**
- prevalance
- Characteristics of it
- Risk factors
Mechanical back pain is extremely common.
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.
It is characterised by 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.
Risk factors: include obesity, poor posture, a sedentary lifestyle with deconditioning of the paraspinal (core) muscles, poorly-designed seating and incorrect manual handling (bending and lifting) techniques.
- *Degenerative changes in the vertebral column:
- disc degeneration and marginal osteophytosis**
The nucleus pulposus of the intervertebral discs dehydrates with age.
This leads to a decrease in the height of the discs, bulging of the discs and alteration of the load stresses on the joints.
Osteophytes (bony spurs) called syndesmophytes therefore develop adjacent to the end plates of the discs. This is known as marginal osteophytosis.
Increased stress is also placed on the facet joints, which also develop osteoarthritic changes. The facet joints are innervated by the meningeal branch of the spinal nerve, so 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.
- *Herniation of an intervertebral disc i.e. ‘slipped disc’**
- Stages
- How to name discs
Herniation of an intervertebral disc i.e. ‘slipped disc’
‘Slipped disc’ is common. 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.
There are four stages of disc herniation that you need to be aware of:
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.
Naming discs:
When naming discs, the intervertebral disc lying between vertebrae L4 and L5 is called the L4/5 disc. The disc between the L5 vertebrae and the sacrum is the L5/S1 disc. The lumbar nerve roots emerge from below their respective vertebrae (in this part of the spine). The most common sites for ‘slipped disc’ are L4/5 and L5/S1 due to the mechanical loading at these joints.
Types of disc herniations
-
Paracentral prolapse: The nucleus pulposus most commonly herniates posterolaterally (lateral to the posterior longitudinal ligament), causing compression of a spinal nerve root within the intervertebral foramen. This is known as a paracentral prolapse and occurs in 96% of cases (figure 2.47). The nerve most at risk is the transversing nerve root (transiting in the diagram above).
Explanation: Paracentral herniation of the L4/5 disc, the L5 root (the transvering root) is most frequently compressed, because the L4 root (the exiting root) emerges above the level of the L4/5 disc. Similarly, a paracentral herniation of the L5/S1 disc compresses the S1 root, not the L5 root RISK OF SCIATICA -
Far lateral prolapse: The nerve root that emerges from the spinal canal at the same level as the intervertebral disc is termed as the exiting nerve root. This is the most at risk in a far lateral disc herniation.
In 2% of cases, the herniation is ‘far lateral’ (image below). RISK OF SCIATICA - Central herniation: Central prolapse i.e. directly towards the spinal cord. RISK OF CAUDA EQUINA
- *Summary:
- In paracentral prolapse,** the transversing nerve root is most frequently compressed.
- *-Far lateral prolapse** (roughly 2% of cases), the exiting nerve root is most at risk
- Central disc herniation is that carries a risk of causing cauda equina syndrome, which as you know is a medical emergency.
- *Sciatica**
- What is this?
- Which nerves?
- Pain is…
- Distribution of pain
Radicular leg pain (“Sciatica”) Sciatica is 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).
Causes include: marginal osteophytosis, slipped disc etc (see description above – paracentral and far lateral prolapse)
The pain experienced is typically experienced in the back and buttock and radiates to the dermatome supplied by the affected nerve root. Pain: Hence it follows a path ‘from the back to the dermatome’ (radiating pain – from path to dermatome).
Typical distribution of pain:
- 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
If the nerve compression also causes paraesthesia (abnormal sensation e.g. pins and needles, tingling), this will be only experienced in the affected dermatome (rather than the full path from lumbar spine to dermatome)
Test: Straight leg test
- *Cauda Equina Syndrome**
- What is this
- Causes
- 5 red flags
- Diagnosis
- Treatment
Cauda equina syndrome can develop in the context of prolapsed intervertebral disc when there is a ‘canal filling disc’ that compresses the lumbar and sacral nerve roots within the spinal canal (e.g. a central herniation). Approximately 5% of cases of cauda equina syndrome are due to a disc prolapse. This most commonly occurs in people aged 30 – 50 years.
Other causes include: tumours (primary or secondary) affecting the vertebral column or meninges, spinal infection / abscess, spinal stenosis secondary to arthritis, vertebral fracture, spinal haemorrhage, and late-stage ankylosing spondylitis. Anything that outs pressure at this part of the spine (below the conus medullaris)
The 5 red flag symptoms are:
· Bilateral sciatica
· Perianal numbness (saddle anaesthesia) – see diagram below
· Painless retention of urine
· Urinary / faecal incontinence
· Erectile dysfunction
Diagnosed: MRI (the key one), can use x-rays, CT
Treatment: Cauda equina syndrome needs to be treated by surgical decompression within 48 hours of the onset of sphincter symptoms, otherwise the prognosis is poor. The consequences of missing this diagnosis are serious and life-changing e.g. chronic neuropathic pain, impotence, having to perform intermittent self-catheterisation to pass urine, faecal incontinence or impaction requiring manual evacuation of faeces, loss of sensation and lower limb weakness requiring a wheelchair. You do not want to miss a case of cauda equina syndrome! Urgent
- *Spinal canal stenosis**
- What is this
- Causes
- Symptoms
Spinal canal stenosis is an abnormal narrowing of the spinal canal that compresses either the spinal cord or the nerve roots (cauda equina).
Causes:
Spinal canal stenosis tends to affect the elderly and is often due to a combination of:
· Disc bulging
· Facet joint osteoarthritis
· Ligamentum flavum hypertrophy
Other causes include:
· Compression fractures of the vertebral bodies
· Spondylolisthesis (see below)
· Trauma
Symptoms:
The symptoms depend on the region of the cord or nerve roots that are affected. Lumbar stenosis is most common, followed by cervical stenosis.
Symptoms include:
· 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 (see below) The natural history of lumbar canal stenosis is that 70% of patients’ symptoms stay unchanged, 15% get progressively worse and 15% improve with time.
- *Neurogenic claudication**
- What is this
- Causes
- Symptoms
Neurogenic claudication (or pseudoclaudication) is a 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. Neurogenic means that the problem originates in the nerve and claudication is derived from the Latin for limp (claudigo), as the patient feels a cramping pain or weakness in their legs, and therefore tends to limp.
Cause:
It results from compression of the spinal nerves as they emerge from the lumbosacral spinal cord (see spinal canal stenosis above). 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.
Neurogenic claudication may be present in one or both legs. It is classically relieved by rest (most effective), a change in position and by flexion of the spine (see image below). Movements that involve flexion of the waist are well tolerated such as cycling, pushing a trolley and climbing stairs
- *Spondylolisthesis**
- What is this
- Causes
Spondylolisthesis is anterior displacement of the vertebra above relative to the vertebra below. It is classified into various types according the underlying cause (You should aim to broadly understand these but do not need to memorise the classification in Phase 1):
Cause:
· Congenital or dysplastic: congenital instability of the facet joints
· Isthmic: A defect in the pars interarticularis
· Degenerative: results from facet joint arthritis and joint remodelling (age >50 years)
· Traumatic: Acute fractures in the neural arch, other than the pars interarticularis
· Pathological: Infection or malignancy
· Iatrogenic: Caused by surgical intervention e.g. if too much lamina and facet joint is excised during a laminectomy operation
- *Spondylolysis**
- What is this
- Treatment
A complete fracture in this location without displacement is referred to as spondylolysis. Once anterior displacement of the upper vertebra occurs, this is spondylolisthesis. Spondylolisthesis may, or may not, be associated with gross instability of the vertebral column. Some individuals remain asymptomatic, but most complain of some discomfort ranging from occasional lower back pain to incapacitating mechanical pain, sciatica from nerve root compression, and neurogenic claudication. The treatment is surgical using screws and rods to stabilise the spine.
One method for spotting spondylolysis is to trace the outline of a ‘Scottie dog’ in oblique views of the spine. Undisplaced fractures through the pars interarticularis (i.e. spondylolysis), look like a collar on the dog (indicated with an arrow on the ‘blue dog’ in the X-ray below). If the dogs head is detached from the body, this indicates that spondylolisthesis has occurred.
However, you should however be able to spot a grossly-displaced spondylolisthesis yourself by tracing the line of the anterior and posterior longitudinal ligaments and thereby detecting the ‘step’ at the site of the displacement. The image below shows how drawing these lines on an X-ray can enable you to identify an L5/S1 spondylolisthesis:
Lumbar puncture
- Position of the patient
- Steps
- Layers
Position the patient: lying on their side in a fetal position: ask the patient to flex forwards whilst bringing their knees up towards their chest.
Identify the lumbar puncture site:
Map out the nnsertion site on the patient:
- With the patient standing, mark out L4 by joining a line between the highest points of the iliac crests.
- Palpate above for L3 and below for L5.
- The insertion site can be marked out either between L3/4 or L4/5 depending on the patient’s anatomical features.
Press the lumbar puncture needle to the patient’s skin over the insertion site and ask if it feels sharp (if it does, it suggests more local anaesthetic or time is needed).
If the patient is unable to feel the sharp sensation you should proceed with performing the lumbar puncture.
Advance the lumbar puncture needle through the insertion site slowly, tilted slightly cranially. The bevel of the needle should face laterally as you insert it. If using an atraumatic needle, you first insert the short introducer needle and then insert the longer atraumatic needle through this.
The needle passes through the following layers before it reaches the subarachnoid space:
- Skin
- Subcutaneous fat
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum
- Dura mater
- Subdural space
- Arachnoid mater
As the needle passes through the three defined ligaments, three ‘pops’ (sudden reductions in resistance) will normally be felt. After the third ‘pop’ (ligamentum flavum) the dura should be breached and CSF should begin to flow through the lumen of the lumbar puncture needle. If there is no CSF flowing through the needle, try withdrawing the needle very slightly and rotating the bevel of the needle to face cranially.
