MSK - Back Pain Flashcards
What are the hallmark symptoms of Cauda Equina?
- Lower back pain
- Unilateral / bilateral leg pain / weakness
- Neurogenic bladder dysfunction - disruption to bladder sensation causes retention (bladder can’t tell brain it’s full) then overflow incontinence
- ↓ perianal sensation - saddle anaesthesia
- ↓ anal tone
What is the mechanism that causes cauda equina?
List some causes.
The spinal cord terminates at the conus medullaris (L1/2).
After this point spinal nerves continue as a bundle called the cauda equina. Compression of these nerves in the lumbro-sacral region causes the syndrome.
Causes:
- Disc herniation (most common)
- Spinal stenosis
- Tumour
- Trauma
- Spinal epidural haematoma (rare anaesthetic/surgical complication)
- Is collection of blood in space between dura and vertebrae periosteum
- Epidural abscess
What are the investigations of choice for
suspected Cauda equina syndrome?
MRI - best evaluates neurologic compression
CT myelography - investigation of choice if can’t have MRI
Myuelography = form of fluoroscopy, inject contrast into spinal subarachnoid space
How is Cauda Equina syndrome treated?
Urgent surgical decompression within 48 hours
Discectomy or laminectomy
If a patient present with back pain, what conditions could cause back pain but not originate in the back?
- Peptic ulcer
- Acute pancreatitis
- Pancreatic cancer
- Ruptured AAA
- Pyelonephritis - costovertebral angle pain
What are ‘Red Flag’ symptoms of spinal pain?
- Age <20 years or >50 years
- Fever
- Pain at night, progressive or constant pain, pain lying flat
- Alcohol or drug use
- Trauma
- Weight-loss
- Reduced appetite
- History of cancer
- Neurology – weakness, numbness
- Bladder or bowel symptoms
What is an osteoporotic vertebral compression fracture (wedge fracture) ?
- Vertebral body fracture due to axial loading
- Most commonly affects anterior aspect - producing wedge shaped vertebra
- Typically are insufficiency fractures secondary to osteoporosis
- Most common fragility frature + most common spine fracture
What is considered normal lumbar flexion in the modified Schober’s Test?
What is the main pathology that Schober’s test targets?
≥ 5cm
Ankylosing spondylitis
What are the initial / non-invasive treatments that come under conservative treatment of back pain / sciatica?
- Education: nature of lower back pain, red flags
- Avoid triggers
- Weight loss
- Local modalities: heat or ice
- Do not offer US, PENS or TENS for management
- Mobility devices + home modifications e.g. special chairs
- Exercise / activity: Return to normal activities
- Avoid bed rest for > 2 days
- Pain management:
- Paracetamol ineffective for back pain
- NSAIDs = 1st line - co-prescribe PPI in pts > 45 yrs and account for GI, liver and renal toxicity
- Weak opiods e.g. codeine
- Physiotherapy - once pain is controlled
What does the natural recovery in most patients
with lower back pain look like?
Natural recovery is favourable - most recover from acute episode in 6-12 weeks
- 50% recover in 2 weeks
- 70% recover in 1 month
- 90% recover by 4 months
- If pt fails to recover by 4 months then they are more likely to progress to long-term chronic back pain
Disc herniation and spinal stenosis are 2 common casues of back pain - at what ages are each more common?
- Disc herniations = more common in patients < 50 years
- Spinal stenosis = more common in patients > 60 years
A prolapsed lumber disc tends to have the main features:
- leg pain usually worse than back
- pain often worse when sitting
A prolapsed lumbar disc produced clear dematomal leg pain + neurlogical deficits depending on the level of the prolapse.
For the following describe the pattern of leg pain + neurological deficit:
- L3 nerve root compression
- L4 nerve root compression
- L5 nerve root compression
- S1 nerve root compression
-
L3 nerve root compression
- Sensory loss over anterior thigh
- Weak quadriceps
- Reduced knee reflex
- Positive femoral stretch test (lie prone, knee flexed to thigh, thigh extended –> pain = +ve)
-
L4 nerve root compression
- Sensory loss anterior aspect of knee
- Weak quadriceps
- Reduced knee reflex
- Positive femoral stretch test
-
L5 nerve root compression
- Sensory loss dorsum of foot
- Weakness in foot and big toe dorsiflexion
- Reflexes intact
- Positive sciatic nerve stretch test (straight leg raise pain = +ve)
-
S1 nerve root compression
- Sensory loss posterolateral aspect of leg and lateral aspect of foot
- Weakness in plantar flexion of foot
- Reduced ankle reflex
- Positive sciatic nerve stretch test
For pts with lower back pain resistant to inital conservative management, what alternative non-surgical approaches can be used?
Pain Clinic
- Multidisciplinary team
- Physiotherapy
- Occupational therapy
- Phsychotherapy
- Address complex issues related to pain behaviours
- Identify psychosocial barriers to treatment
- Different medication called ‘pain modifying medication’:
- Gabapentin
- Amitryptiline
TENS is often used by pain clinics in the treatment of resistant lower back pain.
What is TENS?
Transcutaneous electrical nerve stimulation
- Small electrodes on superficial skin
- Gate theory of pain: stimulation of large myelinated fibres at the level of the spinal cord blocks transmission of pain by small unmyelinated fibres (pain fibres) at the level of the spinal cord
What invasive, non-surgical interventions can be considered for back pain?
-
Radiofrequency denervation when:
- Non-surgical treatments not working AND
- Main pain source comes from structures supplied by medial branch nerve AND
- Pain score > 5/10
- Only use after a +ve response to diagnostic medial branch block
- Medial branch nerve = small nerves that carry pain signals from spinal facet joints (see pic)
-
Epidural - acute / severe sciatica
- Local anaesthetic + steorid
- Don’t use in spinal stenosis
What is spondylolysis?
- Cogenital or acquired defect / stress fracture in pars interarticularis of the vertebral arch - often L4/L5
- Pars interarticularis = part of vertebra located between inferior and superior articular processes of the facet joint (lies between lamina and pedicle)
- Spondyolysis is the commonest cause of spondylolisthesis in children
- Asymptomatic cases = no treatment
What is Spondylolisthesis?
- When one vertebra is displaced relative to it’s immediate inferior vertebral body
- Features:
- Stiff back
- Lower back pain + shooting pain form buttocks to posterior thigh
- Abnormal posture + gait
- Guteal muscle atrophy due to lack of use in gait
- If pt has radicular symptoms / signs then will often require spinal decompression + stabilisation
