• The clinical features of a spinal cord lesion depend on its rate of development
• Trauma produces acute compression with rapidly developing effects
• Benign neoplasms can cause substantial compression with little neurological deficit

Anatomy

• The spinal cord is shorter than spinal canal
• The cord ends at the interspace between the L1 and L2 vertebrae
• Below the termination of the cord the nerve roots form the cauda equina
• Within cervical spine segmental levels of cord correspond to bony landmarks
• Below this level there is increasing disparity between levels
• Spinal pathology below L1 presents with only root signs

Aetiology

• Trauma - vertebral body fracture or facet joint dislocation
• Neoplasia - benign or malignant
• Degenerative - prolapsed intervertebral disc, osteophyte formation
• Vascular - epidural or subdural haematoma
• Inflammatory - rheumatoid arthritis
• Infection - tuberculosis  or pyogenic infections

Clinical presentation

• Clinical features depend on extent and rate of development of cord compression
• Motor symptoms include easy fatigue and gait disturbance
• Cervical spine disease produces quadriplegia
• Thoracic spine disease produces paraplegia
• Lumbar spine disease affects L4, L5 and sacral nerve roots
• Sensory symptoms include sensory loss and paraesthesia
• Light touch, proprioception and joint position sense are reduced
• Tendon reflexes are often:
  • Increased below level of compression
  • Absent at level of compression
  • Normal above level of compression
• Reflex changes may not coincide with sensory level
• Sphincter disturbances are late features of cervical and thoracic cord compression
• Cauda equina compression due to central disc prolapse produces:
  • Loss of perianal sensation
  • 'Root pain' in both legs
  • Painless urinary retention
• Most patients with surgical treatable causes of spinal compression have spinal pain
• Movement induce pain suggests vertebral fracture or collapse
• Exquisite tenderness suggests an epidural abscess
• Low-grade background pain suggests tumour infiltration or osteomyelitis

Investigation

• Plain x-rays may show bone or paravertebral soft tissue disease
• Features include vertebral collapse, lytic lesions, loss of pedicle
• Integrity of disc may indicate diagnosis
• 'Good disc = bad news' often indicates malignancy
• 'Bad disc = good news' may indicate infection
• MRI is investigation of choice to define extent of soft tissue disease
• Bone scan may indicate pattern and extent of bone pathology

Management

• Acute cord compression is a 'surgical' emergency
• In those with malignant disease radiotherapy may be treatment of choice
• In general, tumour, infection and disc disease produces anterior compression
• Surgical decompression should be achieved through an anterior approach
• Cervical spine can be approached between larynx medially and carotid sheath laterally
• Thoracic spine can be approached through chest by a posterior thoracotomy or costotransversectomy

Bibliography

Gleave J R W,  MacFarlane R.  Cauda equina syndrome:  what is the relationship between timing of surgery and outcome?  Br J Neurosurg 2002;  16:  325-328.

Healey J H,  Brown H K.  Complications of bone metastases.  Cancer 2000;  88 (Suppl 1): 2940-2951.