Summary

Lumbar Disc Herniation (LDH) is the displacement of disc material (Nucleus Pulposus) beyond the intervertebral disc space, compressing a nerve root. This causes Radiculopathy (Sciatica): severe shooting pain in a specific dermatome. 95% of herniations occur at L4/L5 (compressing L5 root) or L5/S1 (compressing S1 root). The natural history is highly favourable: 90% of patients recover without surgery within 3-6 months as the disc material desiccates and resorbs. Management is primarily conservative (Analgesia, Physiotherapy, Nerve Root Injections). Surgery (Microdiscectomy) is reserved for progressive neurological deficit or intractable pain failing conservative care. [1,2,3]

Key Facts

• Most Common Levels: L4/5 and L5/S1.
• The "Traversing" Root: A paracentral disc at L4/5 usually misses the exiting L4 root but catches the traversing L5 root as it goes down to the next level.
• Natural History: Most discs shrink. The immune system recognizes the nucleus pulposus as "foreign" and attacks/resorbs it (macrophage mediated).

Clinical Pearls

"L5 Lifts, S1 Stands": To test L5, ask the patient to heel walk (Lift toes). To test S1, ask them to toe walk (Stand on toes).

"The Chemotherapy of the Spine": Sciatica is not just pressure; it's inflammation. The nucleus pulposus is acidic and inflammatory. This is why steroids (oral or injected) often help the pain even if the disc hasn't moved.

"Crossed Leg Raise": If lifting the good leg reproduces pain in the bad leg, this is highly specific for a large herniated disc.

                 SCIATIC PAIN (RADICULOPATHY)
                        ↓
             RED FLAGS? (CES / Cancer / Infection)
             ┌──────────┴──────────┐
           YES                    NO
            ↓                     ↓
        URGENT MRI           CONSERVATIVE CARE
       (Refer Specialist)    (Standard Pathway)
                                  ↓
                             PHARMACOLOGY
                             (NSAIDs, Neuropathic Agents)
                             + PHYSIOTHERAPY
                                  ↓
                             IMPROVED AT 6 WEEKS?
                           ┌──────┴──────┐
                         YES             NO
                          ↓              ↓
                     DISCHARGE          MRI
                                         ↓
                                    DISC CONFIRMED?
                                         ↓
                                    MANAGEMENT
                             ┌───────────┴───────────┐
                       INJECTION                  SURGERY
                 (Transforaminal Epidural)    (Microdiscectomy)
                 Usually tried first          Relieves leg pain

1. Conservative (Up to 12 weeks)

• Keep Moving: Bed rest is harmful. Continue normal activity as tolerated.
• Medication: L2 Ladder.
  • NSAIDs (Anti-inflammatory).
  • Neuropathic Agents: Amitriptyline (Night), Gabapentin/Pregabalin.
  • Weak Opioids: Short term only.
• Physio: Core stability, McKenzie exercises.

2. Nerve Root Block (Injection)

• Transforaminal Epidural Steroid: Targeted CT/X-ray guided injection of steroid + anaesthetic around the angry nerve root.
• Intent: Symptom relief (dampens inflammation) to allow natural resorption. 50-60% gain good relief.
• Diagnostic: If pain vanishes immediately (anaesthetic), it confirms that root is the cause.

3. Surgical: Lumbar Microdiscectomy

• Indication:
  1. Cauda Equina Syndrome (Emergency).
  2. Progressive motor weakness (e.g., foot drop).
  3. Intractable pain failing conservative care (>6-12 weeks).
• Technique: Small incision. Microscope used. Drill lamina (laminotomy). Retract nerve root. Pluck out loose disc fragment.
• Outcome: 85-90% relief of LEG pain. Back pain may persist.
• Risk: Recurrent herniation (5-10%), Dural tear, Nerve injury.

The SPORT Trial (Weinstein et al.)

• Comparison: Surgery vs Conservative for Disc Herniation.
• Finding: Surgery relieved pain FASTER. Both groups were similar at 2 years (crossover was high).
• Conclusion: Surgery is a time-accelerator. It gets you better quicker, but you likely get better eventually anyway.

NICE Guidelines (NG59)

• Advise against spinal fusion for simple disc disease.
• Advise against opioids for chronic back pain.
• Recommend exercise and manual therapy.

What is a Slipped Disc?

The cushion between your back bones has a tough skin and a jelly center. A tear in the skin allowed the jelly to squirt out. This jelly is pressing on the nerve that runs down your leg.

Will it go back in?

Not exactly back in, but your body will eat it up. Your immune system sees the jelly as "rubbish" and dissolves it over 3-6 months. That's why we usually wait.

Why does my leg hurt if the problem is in my back?

The nerve is like a telephone wire. The problem is at the exchange (your back), but the signal (pain) is felt at the handset (your leg).

When do I need surgery?

If you lose bladder control (Emergency), if your foot goes weak (floppy), or if the pain is unbearable despite months of treatment. Surgery just removes the piece of jelly; it doesn't give you a new disc.

Q1: What are the signs of an L5 nerve root compression? A: Motor: Weakness of Big Toe Extension (EHL) and Hip Abduction. Sensory: Numbness in the first web space / dorsum of foot. Reflex: Usually no specific reflex change (sometimes medial hamstring).

Q2: Describe the "Crossed Straight Leg Raise" sign. A: Passive elevation of the unaffected (well) leg reproduces sciatica in the affected (bad) leg. This is highly specific (>90%) for a herniated disc, implying a large central/axillary herniation.

Q3: Why is Cauda Equina Syndrome an emergency compared to a simple foot drop? A: CES involves compression of the sacral roots controlling autonomic bladder/bowel function. Once these nerves differntiate (die), recovery of continence is rare, leading to lifelong disability. A foot drop is a single peripheral motor deficit; while important, it does not carry the same systemic morbidity as incontinence.

(End of Topic)