Pathophysiology

1. Disc consists of outer annulus fibrosis and inner nucleus pulposus
2. Herniation = rupture of nucleus pulposus through annulus with material going into spinal cord 

Approach

• Expose back
• Be gentle

Features to extract

1. Age
2. Occupation
3. Features of pain
4. Neurological symptoms
5. Sphincter disturbance
6. Effect on lifestyle - sleep
7. Previous treatments - analgesia, physiotherapy, epidurals, operative intervention
8. Other causes of back pain: AAA, renal causes

1. Look
   • Gait
   • Skin - scar, sinuses
   • Spine position / curvature
   • Posture: "sciatic list" - reduced nerve irritation by opening up spinal foramen by moving to one side
2. Feel
   • Erector spinae muscle spasm
3. Move
   • Forward flexion: should be able to reach within 5cm of floor
   • Extension: normally 30'
   • Lateral flexion
   • Rotation: fix pelvis (yourself/get patient to sit), cross arms, turn
   • Straight leg raise: demonstrates lumbosacral nerve root irritation (normally 80'; Lasegue's sign positive if pain felt in the back, buttock and thigh)
   • Crossed SLR: SLR on unaffected leg produces pain on affected side
   • Sciatic stretch test: SLR + dorsiflexion of foot causes pain
4. Neurological examination of lower limbs
   • Tone
   • Power
   • Reflexes
   • Sensation: dermatomes
     

     Disc	Nerve root	Sensory distribution	Motor signs	Reflexes
     L4/5	L5	Lateral aspect of leg and dorsum of foot	Weakness of big toe extension and dorsiflexion
     L5/S1	S1	Lateral aspect of foot and heel	Weakness of ankle plantarflexion and foot eversion	Ankle je

Completion

1. Examine prone
2. Perform femoral stretch test (reverse lasengue)
3. Peripheral vascular examination
4. DRE - check anal tone; perianal sensation and anal reflex to exclude cauda equina compression

Factors increasinf risk of developing symptomatic disc disease

1. Physiological
   • Age
   • Posture
   • Overall aerobic fitness (or lack of!)
   • Poor strenght of spinal extensor and abdominal muscles
   • Decreased spinal mobility
2. Environmental
   • Smoking
3. Occupational
   • Heavy physical work
   • Frequent bending, lifting, pushing, pulling, twisting
   • Repetitive work postures
   • Static work postures
   • Vibration

Management of lumbar disc herniation

1. Non-surgical
   • Bed rest (not more than 2 days), analgesia (muscle relaxant, NSAID)
   • Physiotherapy - muscle strengthening and stabilisation with emphasis usually on extension exercises
2. Epidural analgesia
   • Injection of a long-acting steroid with epidural analgesia results in 60-85% short-term pain relief which falls to 30-40% at 6 months
3. Surgery: with neurological defect or incapacitating pain
   • Chemonucleolysis of disc (with chymopapain) ~70% but rarely used due to complications such as as severe post-operative pain and spasms
   • Percutaneous discectomy: decompress nerve root by removing materal from centre of the disc space
   • Endoscopic discectomy
   • Laminectomy