Neurosurgery Flashcards
Pathophysiology of disc prolapse
Herniation of nucleus pulposus through annulus fibrosus
What’s spinal cord compression?
a common group of patients
Spinal cord compression
- an oncological emergency
- affects up to 5% of cancer patients
- Extradural compression accounts for the majority of cases, usually due to vertebral body metastases
- It is more common in patients with lung, breast and prostate cancer
Features of spinal cord compression
- back pain - the earliest and most common symptom - may be worse on lying down and coughing
- lower limb weakness
- sensory changes: sensory loss and numbness
- neurological signs depend on the level of the lesion
*Lesions above L1 usually result in upper motor neuron signs in the legs and a sensory level
*Lesions below L1 usually cause lower motor neuron signs in the legs and perianal numbness. Tendon reflexes tend to be increased below the level of the lesion and absent at the level of the lesion
Mx of spinal cord compression
- high-dose oral dexamethasone
- urgent oncological assessment for consideration of radiotherapy or surgery
Presentation of disc prolapse
- L5 and S1 roots most commonly compressed by prolapse of L4/5 and L5/S1 discs
- May present as severe pain on sneezing, coughing or twisting a few days after low back strain
- Lumbago: low back pain
- Sciatica: shooting radicular pain down buttock and thigh
Signs of L4/L5 root compression
L4/5 → L5 Root Compression
• Weak hallux extension ± foot drop
- In foot drop due to L5 radiculopathy, weak
inversion (tib. post.) helps distinguish from peroneal N. palsy
• ↓ sensation on inner dorsum of foot
Signs of L5/S1 root compresison
L5/S1 → S1 Root Compression
- Weak foot plantarflexion and eversion
- Loss of ankle-jerk
- Calf pain
- ↓ sensation over sole of foot and back of calf
Management of disc prolapse
- Conservative: Brief rest, analgesia and mobilisation effective in ≥90%; physio
- Medical: analgesia, transforaminal steroid injection
- Surgical: discectomy or laminectomy may be needed in cauda-equina syndrome, continuing pain or muscle weakness
Indications for surgery in disc prolapse (3)
Surgical: discectomy or laminectomy may be needed in:
- cauda-equina syndrome
- continuing pain
- muscle weakness
Signs of Acute Cord Compression
Acute Cord Compression = emergency!
- Bilateral pain: back and radicular
- LMN signs at compression level
- UMN signs and sensory level below compression
- Sphincter disturbance
Signs of Cauda Equina
Acute Cauda Equina Compression
- Alternating or bilateral radicular pain in the legs
- Saddle anaesthesia
- Loss of anal tone
- Bladder ± bowel incontinence
Treatment of different causes (3) of acute cord compression
Acute cord compression = EMERGENCY
- Large prolapse: laminectomy / discectomy
- Tumours: radiotherapy and steroids
- Abscesses: decompression
What’s extradural haematoma
An extradural (or ‘epidural’) haematoma is a collection of blood that is between the skull and the dura
What’s that?
Extradural haemorrhage
Cause of extradural haemorrhage
It is almost always caused by trauma and most typically by ‘low-impact’ trauma (e.g. a blow to the head or a fall)
The most common artery affected in extradural haemorrhage
- often in the temporal region since the thin skull at the pterion overlies the middle meningeal artery and is therefore vulnerable to injury.
The classical presentation of extradural haemorrhage
(2 signs and why)
- Luicid interval
- Apatient who initially loses, briefly regains and then loses again consciousness after a low-impact head injury
- The brief regain in consciousness is termed the ‘lucid interval’ and is lost eventually due to the expanding haematoma and brain herniation.
- Fixed and dileted pupils
-As the haematoma expands the uncus of the temporal lobe herniates around the tentorium cerebelli
-the patient develops a fixed and dilated pupil due to the compression of the parasympathetic fibers of the third cranial nerve
Ix and characteristic appearance in Extradural Haemorrhage
CT head
On imaging, an extradural haematoma appears as a biconvex (or lentiform), hyperdense collection around the surface of the brain
They are limited by the suture lines of the skull