High-yield overview
Radicular Pain | Straight Leg Raise | Microdiscectomy for Failed Conservative Care
5-10%Adults experience sciatica in lifetime
90%Resolve with conservative care at 6 weeks
L4-L5/L5-S1Most common levels (95%)
5-10%Recurrence rate after microdiscectomy
HERNIATION TYPES (NASS NOMENCLATURE)
Protrusion
PatternBase wider than dome, contained
TreatmentConservative
Extrusion
PatternBase narrower than dome, may migrate
TreatmentConsider surgery if symptomatic
Sequestration
PatternFragment separated from disc
TreatmentOften surgical
Critical Must-Knows
- Radicular pain (leg worse than back) is hallmark - back pain alone is NOT disc herniation
- Straight leg raise (SLR) positive if reproduces radicular pain below knee at less than 60 degrees
- MRI confirms clinical diagnosis - never operate on imaging alone without matching symptoms
- Conservative management first - 90% improve by 6 weeks without surgery
- Surgery indicated for: cauda equina, progressive motor deficit, or failed 6 weeks conservative care
- Microdiscectomy gold standard - remove herniated fragment, preserve disc space, early mobilization
Clinical Pearls
- "SLR positive at less than 60 degrees with radicular pain = disc herniation until proven otherwise
- "Crossed SLR (raising opposite leg reproduces ipsilateral leg pain) is highly specific
- "L5-S1 disc herniation affects S1 nerve root (ankle jerk, plantar flexion, lateral foot numbness)
- "Cauda equina syndrome = surgical emergency - saddle anesthesia, bowel/bladder dysfunction, bilateral symptoms
- "SPORT trial: surgery provides faster relief but similar 4-year outcomes to conservative care
Clinical Imaging
Imaging Gallery
Critical Lumbar Disc Herniation Exam Points
Radicular Pain Dominates
Leg pain worse than back pain is the key feature. Pure back pain without radiculopathy is NOT a disc herniation presentation. Sciatica follows dermatomal distribution below the knee.
Clinical-Radiological Correlation
MRI confirms clinical diagnosis. Never operate based on imaging alone. Up to 30% of asymptomatic adults have disc bulges on MRI. Match imaging level to clinical examination findings.
Conservative Care First
90% improve with conservative management within 6 weeks. Surgery is for failed conservative care, progressive motor deficit, or cauda equina syndrome. Natural history favors non-operative treatment.
Cauda Equina is an Emergency
Saddle anesthesia, bowel/bladder dysfunction, bilateral leg symptoms = cauda equina syndrome. Requires urgent MRI and emergency decompression within 24-48 hours to prevent permanent dysfunction.
Quick Decision Guide - Management Algorithm
| Presentation | Clinical Features | Management | Key Pearl |
|---|---|---|---|
| Acute radiculopathy, no red flags | Leg pain worse than back pain, positive SLR, intact motor/reflexes | Conservative: NSAIDs, physio, nerve root injection | 90% resolve by 6 weeks - reassure patient |
| Persistent radiculopathy 6 weeks | Failed conservative care, impacting function | MRI, consider microdiscectomy | Surgery for quality of life, not cure |
| Progressive motor deficit | Worsening foot drop, EHL weakness grade 3 or less | Urgent MRI, early surgery (within 2 weeks) | Footdrop may not fully recover if delayed |
| Cauda equina syndrome | Saddle anesthesia, bowel/bladder dysfunction, bilateral | Emergency MRI, immediate decompression | Operate within 24-48h to prevent permanent deficit |
Mnemonic
DISCDISC - Herniation Characteristics
| D | Dermatomal distribution Radicular pain follows nerve root pattern |
| I | Imaging confirmation MRI shows herniation matching clinical level |
| S | Straight leg raise positive Reproduces leg pain at less than 60 degrees |
| C | Conservative care first 90% improve without surgery by 6 weeks |
| D | Dermatomal distribution Radicular pain follows nerve root pattern | S | Straight leg raise positive Reproduces leg pain at less than 60 degrees |
| I | Imaging confirmation MRI shows herniation matching clinical level | C | Conservative care first 90% improve without surgery by 6 weeks |
Hook:DISC reminds you that herniation causes radicular pain confirmed by imaging and SLR
Mnemonic
SCIATICASCIATICA - Red Flags for Surgery
| S | Saddle anesthesia Cauda equina syndrome - emergency |
| C | Cauda equina symptoms Bowel/bladder dysfunction |
| I | Intolerable pain Failed 6 weeks conservative care |
| A | Acute motor deficit Progressive foot drop, EHL grade 3 or less |
| T | Timing critical CES needs surgery within 24-48 hours |
| I | Imaging matches symptoms MRI level correlates with clinical findings |
| C | Conservative failed 6 weeks physio, NSAIDs, injections tried |
| A | Affecting function Unable to work, significant disability |
| S | Saddle anesthesia Cauda equina syndrome - emergency | A | Acute motor deficit Progressive foot drop, EHL grade 3 or less | C | Conservative failed 6 weeks physio, NSAIDs, injections tried |
| C | Cauda equina symptoms Bowel/bladder dysfunction | T | Timing critical CES needs surgery within 24-48 hours | A | Affecting function Unable to work, significant disability |
| I | Intolerable pain Failed 6 weeks conservative care | I | Imaging matches symptoms MRI level correlates with clinical findings |
Hook:SCIATICA reminds you when surgery is indicated for disc herniation
Mnemonic
ROOTSROOTS - Nerve Root Examination
| R | Reflex testing Knee jerk (L4), ankle jerk (S1) |
| O | Observation for atrophy Calf wasting in chronic S1 radiculopathy |
| O | Opposition strength EHL (L5), plantar flexion (S1) |
| T | Touch sensation Dermatomal patterns - dorsum foot (L5), lateral foot (S1) |
| S | Straight leg raise SLR positive if less than 60 degrees reproduces leg pain |
| R | Reflex testing Knee jerk (L4), ankle jerk (S1) | T | Touch sensation Dermatomal patterns - dorsum foot (L5), lateral foot (S1) |
| O | Observation for atrophy Calf wasting in chronic S1 radiculopathy | S | Straight leg raise SLR positive if less than 60 degrees reproduces leg pain |
| O | Opposition strength EHL (L5), plantar flexion (S1) |
Hook:Test all ROOTS components to identify which nerve root is compressed
Mnemonic
MICROMICRO - Microdiscectomy Technique
| M | Midline incision 2-3cm centered over interspace |
| I | Interlaminar window Remove ligamentum flavum, expose disc |
| C | Careful nerve retraction Protect nerve root and dura during fragment removal |
| R | Remove fragment only Do not excise entire disc - preserve disc space |
| O | Out same day/next day Early mobilization, discharge within 24 hours |
| M | Midline incision 2-3cm centered over interspace | R | Remove fragment only Do not excise entire disc - preserve disc space |
| I | Interlaminar window Remove ligamentum flavum, expose disc | O | Out same day/next day Early mobilization, discharge within 24 hours |
| C | Careful nerve retraction Protect nerve root and dura during fragment removal |
Hook:MICRO technique is minimally invasive with focus on fragment removal
Overview and Epidemiology
Lumbar disc herniation is the most common cause of sciatica (radicular leg pain). The intervertebral disc herniates posterolaterally, compressing the exiting nerve root in the lateral recess or foramen.
Natural history:
- Spontaneous resolution is the norm - herniated disc fragments resorb over time
- 90% of patients improve with conservative care within 6 weeks
- Surgical intervention is reserved for specific indications, NOT a primary treatment
- Large sequestered fragments paradoxically have better prognosis (more inflammatory resorption)
Why Disc Herniation Resolves
Disc fragments undergo inflammatory resorption. Extruded and sequestered fragments (exposed to epidural space) have more contact with blood supply and macrophages, leading to faster resorption than contained protrusions. This explains why large herniations may resolve faster than small ones.
Epidemiology:
- Peak incidence: 30-50 years (disc still has nucleus pulposus hydration)
- Male to female: 2:1 ratio
- Risk factors: Heavy lifting, vibration exposure, smoking, obesity, genetics
- Level distribution: L4-L5 (45%), L5-S1 (50%), L3-L4 (5%), higher levels rare
Pathophysiology and Mechanisms
Intervertebral disc structure:
Nucleus Pulposus
- Composition: 80% water, proteoglycans (aggrecan), type II collagen
- Function: Absorbs compressive loads, distributes forces
- Age changes: Dehydration, loss of proteoglycans, decreased height
Annulus Fibrosus
- Composition: Type I collagen, organized lamellae, 15-20 layers
- Function: Contains nucleus, resists tensile forces
- Weak zone: Posterolateral annulus (thinnest, lacks support from ALL)
Why posterolateral herniation?
- Anterior longitudinal ligament (ALL): Strong, thick, prevents anterior herniation
- Posterior longitudinal ligament (PLL): Weak centrally, strong midline, narrow laterally
- Posterolateral annulus: Thinnest region, no PLL reinforcement
- Result: 95% of herniations occur posterolaterally into lateral recess
Nerve Root Numbering
Lumbar nerve roots exit BELOW their corresponding pedicle. L4-L5 disc herniation compresses the L5 nerve root (traversing root in lateral recess), NOT L4. The L4 root has already exited above. Far lateral herniations compress the exiting root (L4 at L4-L5 level).
Nerve root anatomy:
- Traversing root: Crosses disc space in lateral recess (e.g., L5 root at L4-L5 level)
- Exiting root: Exits at same level foramen (e.g., L4 root at L4-L5 level, far lateral)
- Dural sac: Contains cauda equina, ends at S1-S2 level
- Conus medullaris: Spinal cord ends at L1-L2 level
Disc herniation zones:
- Central: Midline, may compress multiple roots or cauda equina
- Paracentral: Most common, compresses traversing root
- Foraminal: Within foramen, compresses exiting root
- Far lateral (extraforaminal): Lateral to foramen, compresses exiting root
Classification Systems
North American Spine Society (NASS) Classification
| Type | Definition | Prognosis | Treatment |
|---|---|---|---|
| Normal | No disc extension beyond vertebral body | Not pathological | None |
| Bulge | Circumferential extension, not focal | Usually asymptomatic | Conservative |
| Protrusion | Focal herniation, base wider than dome, contained by annulus | May resolve spontaneously | Conservative first |
| Extrusion | Focal herniation, base narrower than dome, through annulus | May migrate, variable resolution | Consider surgery if symptomatic |
| Sequestration | Fragment separated from parent disc, free in canal | Good prognosis for resorption | Often resolves, surgery if symptomatic |
Sequestered Fragments
Sequestered fragments have BETTER prognosis than contained herniations. They have more contact with vascular tissue and macrophages in the epidural space, leading to faster inflammatory resorption. Large sequestrations often resolve without surgery.
Clinical Presentation and Assessment
Cardinal features of lumbar disc herniation:
History
- Chief complaint: Leg pain worse than back pain (radiculopathy)
- Distribution: Dermatomal pattern below knee
- Character: Sharp, shooting, electric, burning
- Aggravating factors: Sitting, bending forward, Valsalva (cough, sneeze)
- Relieving factors: Standing, lying, walking
- Red flags: Saddle anesthesia, bowel/bladder changes, bilateral symptoms, progressive weakness
Examination
- Gait: Antalgic, footdrop gait if L5 weakness
- Inspection: Scoliosis (sciatic scoliosis - away from side of pain)
- Range of motion: Decreased lumbar flexion
- Straight leg raise: Positive if less than 60 degrees reproduces radicular pain
- Neurological exam: Motor, sensory, reflexes by dermatome/myotome
Straight leg raise (SLR) test:
- Technique: Patient supine, examiner lifts extended leg
- Positive test: Reproduces radicular leg pain (NOT back pain) at less than 60 degrees elevation
- Sensitivity: 90% for disc herniation
- Specificity: 25% (many false positives)
- Crossed SLR: Raising opposite leg reproduces ipsilateral leg pain - highly specific (95%) for disc herniation
SLR Interpretation
SLR is positive only if it reproduces LEG PAIN below the knee, not back pain or hamstring tightness. Pain at greater than 60 degrees is often hamstring or sacroiliac joint pain. Crossed SLR (raising contralateral leg causes ipsilateral sciatica) is highly specific for disc herniation.
Neurological examination by level:
Lumbar Nerve Root Examination
| Level | Motor | Sensation | Reflex | SLR |
|---|---|---|---|---|
| L4 (L3-L4 disc) | Quadriceps, knee extension | Medial leg, medial ankle | Knee jerk (patellar) | Femoral stretch test |
| L5 (L4-L5 disc) | EHL, ankle dorsiflexion, foot eversion | Dorsum of foot, first web space | None (or medial hamstring) | Positive SLR |
| S1 (L5-S1 disc) | Ankle plantar flexion, toe plantar flexion | Lateral foot, sole of foot | Ankle jerk (Achilles) | Positive SLR |
Differential diagnosis of radicular leg pain:
Differential Diagnosis of Sciatica / Radicular Leg Pain
| Diagnosis | Distinguishing features | Key investigation |
|---|---|---|
| Lumbar disc herniation | Leg pain worse than back pain, dermatomal, positive SLR, worse with sitting/Valsalva | MRI: focal posterolateral herniation matching level |
| Lumbar spinal (central) stenosis | Older patient, neurogenic claudication, eased by flexion/sitting, negative SLR | MRI: multilevel canal narrowing, hypertrophic ligamentum flavum/facets |
| Cauda equina syndrome | Bilateral symptoms, saddle anaesthesia, bladder/bowel dysfunction | Emergency MRI: large central compressive lesion |
| Piriformis / deep gluteal syndrome | Buttock pain, normal neurology, pain on resisted external rotation, no clear dermatome | Clinical; MRI normal lumbar spine |
| Peripheral neuropathy (e.g. diabetic) | Stocking distribution, bilateral, non-dermatomal, distal sensory loss | Nerve conduction studies / EMG, glucose/HbA1c |
| Hip osteoarthritis | Groin pain referred to thigh/knee, limited internal rotation, no pain below knee | Hip radiograph; intra-articular anaesthetic block |
| Vascular claudication | Calf pain with walking relieved by standing still, absent pulses, no postural change | ABPI, arterial duplex/angiography |
| Sinister causes (tumour, infection, fracture) | Night pain, weight loss, fever, age extremes, history of malignancy | MRI with contrast, inflammatory markers, bone imaging |
Red flag symptoms requiring urgent assessment:
Cauda Equina Syndrome
Cauda equina syndrome is a surgical emergency:
- Saddle anesthesia (perianal and perineal numbness)
- Bowel dysfunction (incontinence or retention)
- Bladder dysfunction (urinary retention, overflow incontinence, loss of sensation)
- Bilateral leg symptoms (weakness or numbness)
- Sexual dysfunction (erectile dysfunction, loss of sensation)
Management: Urgent MRI, emergency decompression within 24-48 hours. Delayed surgery results in permanent bowel/bladder dysfunction.
Investigations
Imaging Protocol
Acute (0-6 weeks)Clinical Diagnosis
No imaging needed initially for typical radiculopathy without red flags. Natural history favors spontaneous resolution. Treat conservatively and observe.
If Red FlagsUrgent MRI
Immediate MRI for:
- Cauda equina syndrome
- Progressive motor deficit
- Bilateral symptoms
- Severe or rapidly worsening symptoms
After 6 WeeksMRI for Persistent Symptoms
MRI lumbar spine if:
- Symptoms persist despite 6 weeks conservative care
- Considering surgical intervention
- Confirm level and type of herniation
AlternativeCT Myelography
CT myelogram if MRI contraindicated (pacemaker, claustrophobia). Shows nerve root compression and disc herniation. Less detail than MRI for soft tissues.
MRI findings:
T1-Weighted Images
- Normal disc: Intermediate signal
- Degenerated disc: Decreased signal
- Herniation: Intermediate signal, displaces thecal sac or nerve root
- Use: Anatomy, foraminal stenosis, bone marrow changes
T2-Weighted Images
- Normal disc: Bright signal (high water content)
- Degenerated disc: Dark signal (loss of water)
- Herniation: Intermediate signal, may enhance with contrast
- Use: Disc hydration, nerve root compression, CSF bright
MRI and Clinical Correlation
Up to 30% of asymptomatic adults have disc bulges or herniations on MRI. NEVER operate based on imaging alone. The herniation level MUST correlate with clinical examination findings (dermatomal pain, motor weakness, reflex changes). Mismatch between imaging and exam suggests alternate diagnosis.
When to consider EMG/NCS:
- Atypical presentations: Symptoms not matching expected dermatomal pattern
- Peripheral neuropathy suspected: Diabetes, alcoholism
- Timing neurological deficit: Distinguish acute (2-3 weeks for denervation changes) vs chronic
- Medicolegal: Document baseline function before surgery
Management Algorithm
Algorithm
First-line treatment for 6 weeks (unless red flags)
Goal: Symptom relief, facilitate natural history of disc resorption
Conservative Protocol
Acute PhaseWeek 0-2
- Activity modification: Avoid prolonged sitting, heavy lifting, bending
- Analgesia: NSAIDs (if no contraindications), paracetamol, neuropathic agents (gabapentin, pregabalin)
- Short rest: 1-2 days if severe, then encourage mobilization
- Education: Reassure natural resolution, avoid bed rest
Subacute PhaseWeek 2-6
- Physiotherapy: Core strengthening, posture education, nerve glides
- Activity progression: Gradual return to activities as tolerated
- Nerve root injection: Consider if symptoms persist, diagnostic and therapeutic
- Review progress: If improving, continue conservative care
Persistent PhaseWeek 6+
- Reassess: MRI if not already done
- Multidisciplinary input: Pain clinic, psychology, functional restoration
- Consider surgery: If symptoms persist and impacting function/quality of life
Natural History Wins
90% of disc herniations improve with conservative care by 6 weeks. The SPORT trial showed that while surgery provides faster pain relief, outcomes at 4 years are similar between surgical and conservative groups. Surgery is for quality of life and faster return to function, NOT a cure.
Surgical Technique - Microdiscectomy
Pre-operative Checklist
Consent Points
- Recurrence: 5-10% risk of recurrent herniation
- Dural tear: 1-2% risk, usually repaired primarily
- Nerve root injury: Less than 1%, may cause new deficit
- Infection: 1-2% superficial, less than 1% deep (discitis)
- No guarantee: Pain may persist, surgery does not prevent future disc disease
- Cauda equina: Rare postoperative complication from hematoma
Equipment Checklist
- Microscope or loupes: Magnification for nerve root visualization
- Fluoroscopy: Confirm correct level intraoperatively
- Retractors: Self-retaining (e.g., Taylor, Caspar) for exposure
- Curets and pituitary rongeurs: Fragment removal
- Bipolar cautery: Hemostasis around nerve root
- Nerve root retractor: Protect nerve during fragment retrieval
Level localization:
- L4-L5: Most common level - identify iliac crest (L4-L5 level)
- L5-S1: Lumbosacral junction - palpate for sacral prominence
- Fluoroscopy mandatory: Confirm level before incision (wrong level surgery is never event)
Accurate level confirmation prevents wrong-site surgery, which is a never event.
Complications
Microdiscectomy Complications
| Complication | Incidence | Prevention/Management |
|---|---|---|
| Recurrent herniation | 5-10% | Preserve disc height, patient education (avoid heavy lifting), smoking cessation |
| Dural tear | 1-5% | Primary repair if identified, bed rest if unrecognized, reoperation if CSF leak persists |
| Nerve root injury | Less than 1% | Gentle retraction, avoid excessive traction, microsurgical technique |
| Infection (superficial) | 1-2% | Perioperative antibiotics, sterile technique, early debridement if deep |
| Discitis | 0.5-1% | Prolonged antibiotics (6-12 weeks), rest, rarely requires debridement |
| Wrong level surgery | Less than 1% | Fluoroscopy confirmation, preoperative imaging review |
| Epidural hematoma | Less than 1% | Meticulous hemostasis, early recognition (cauda equina symptoms), emergency evacuation |
| Persistent pain | 10-20% | Realistic expectations, not all pain resolves, consider other pain sources |
Recurrent disc herniation:
- Definition: Recurrence of radiculopathy after initial improvement
- Timing: Can occur months to years after surgery
- Same level: Most common (80%)
- Risk factors: Smoking, obesity, heavy lifting, young age, large annular defect
- Management: Conservative first (as per primary herniation), revision discectomy if failed conservative care
Postoperative Cauda Equina
Epidural hematoma can cause acute postoperative cauda equina syndrome. Suspect if patient develops:
- New onset bowel/bladder dysfunction
- Bilateral leg weakness
- Saddle anesthesia
Requires immediate MRI and emergency reoperation for hematoma evacuation. Time-sensitive - operate within hours.
Dural tear management:
- Intraoperative recognition: Repair primarily with 5-0 or 6-0 suture, water-tight fascial closure
- Small tear: May seal with fascial closure and bed rest
- Postoperative CSF leak: Persistent headache, wound drainage - reoperation for repair if conservative measures fail
- Consequences: Meningitis risk, CSF fistula, pseudomeningocele
Postoperative Care and Rehabilitation
Postoperative Protocol
ImmediateDay 0-1
- Mobilization: Get out of bed same day, walk within hours
- Analgesia: Simple analgesia (paracetamol, NSAIDs), minimize opioids
- Wound care: Keep dressing clean and dry
- Discharge: Usually next day (day case in some centers)
EarlyWeek 1-2
- Activity: Light activities, short walks, avoid prolonged sitting
- Driving: After 2 weeks (when safe to perform emergency stop)
- Work: Desk work after 2 weeks, modify heavy work
- No restrictions: On bending, twisting, lifting light objects
ProgressiveWeek 2-6
- Physiotherapy: Core strengthening, posture education
- Activity progression: Gradual return to normal activities
- Avoid: Heavy lifting (greater than 10kg), repetitive bending
- Return to work: Most patients by 6 weeks
RecoveryWeek 6-12
- Full activities: Most activities unrestricted by 3 months
- Sports: Contact sports after 3 months
- Lifting: Gradual progression, proper technique education
OngoingLong-term
- Lifestyle modification: Smoking cessation, weight loss, core strengthening
- Recurrence prevention: Avoid prolonged sitting, heavy lifting
- Follow-up: Discharge at 6 weeks if no concerns
Key rehabilitation principles:
- Early mobilization: Reduces stiffness, improves outcomes
- No prolonged bed rest: Bed rest delays recovery
- Core strengthening: Protects spine from recurrence
- Patient education: Proper lifting technique, ergonomics, weight management
Postoperative Expectations
Leg pain improves immediately, back pain may persist. Microdiscectomy decompresses the nerve root (treats radiculopathy), but does not address disc degeneration or back pain. Set realistic expectations: surgery is for leg pain relief, NOT back pain cure.
Outcomes and Prognosis
Outcomes with microdiscectomy:
| Outcome Measure | Result |
|---|---|
| Leg pain relief | 85-90% good to excellent at 1 year |
| Back pain | Variable, often persists (not primary indication) |
| Return to work | 80-95% by 3 months (depends on occupation) |
| Patient satisfaction | 80-90% satisfied at 1 year |
| Recurrence | 5-10% within 2 years |
Predictors of good outcome:
- Leg pain dominant: Radiculopathy worse than back pain
- Positive SLR: Clear nerve root tension sign
- MRI-clinical correlation: Imaging matches examination
- Acute symptoms: Less than 6 months duration
- Large sequestration: Paradoxically better outcomes (fragment removable)
- First episode: Not revision surgery
Predictors of poor outcome:
- Predominant back pain: Not a microdiscectomy indication
- Chronic symptoms: Greater than 12 months duration
- Psychosocial factors: Secondary gain, litigation, depression
- Multiple level disease: Adjacent segment pathology
- Smoking: Impairs healing, increases recurrence
SPORT Trial Key Findings
The SPORT trial (Spine Patient Outcomes Research Trial) showed:
- Surgery provides faster pain relief than conservative care
- At 4 years, outcomes are similar between surgical and conservative groups
- Crossover was common: Many conservative patients eventually had surgery
- Conclusion: Surgery is for quality of life and faster recovery, NOT superior long-term outcomes
Surgery accelerates what would happen naturally in most cases.
Evidence Base and Key Trials
SPORT Trial (Spine Patient Outcomes Research Trial)
Weinstein JN, Tosteson TD, Lurie JD et al • JAMA (2006)
Key Findings:
- Randomised trial of 501 surgical candidates comparing open discectomy vs individualised non-operative care for imaging-confirmed lumbar disc herniation with at least 6 weeks of radiculopathy
- Both groups improved substantially over 2 years; intent-to-treat between-group differences favoured surgery but were small and not statistically significant for the primary outcomes
- Adherence was limited: only 50% assigned to surgery had surgery within 3 months, while 30% assigned to non-operative care crossed over to surgery
- Companion observational cohort (Weinstein JN et al, JAMA 2006, PMID 17119141) showed greater improvement with surgery, but as a non-randomised comparison must be interpreted cautiously
Clinical Implication: Both surgery and structured non-operative care lead to substantial improvement. High bidirectional crossover means superiority cannot be claimed from the intent-to-treat analysis; surgery offers faster relief for appropriately selected, persistently symptomatic patients.
Limitation: Large bidirectional crossover (50% surgery uptake in the surgical arm, 30% crossover in the non-operative arm) limits intent-to-treat interpretation. Reflects real-world preference-sensitive practice.
Systematic Review: Surgery vs Conservative Care for Sciatica from Disc Herniation
Jacobs WC, van Tulder M, Arts M et al • Eur Spine J (2010)
Key Findings:
- Systematic review of randomised trials of surgery vs conservative therapy (including epidural injections) for sciatica from lumbar disc herniation; 5 studies identified, 2 at low risk of bias
- One large low-risk trial showed early surgery in patients with 6-12 weeks of radicular pain gives faster pain relief than prolonged conservative care, with no difference at 1 and 2 years
- Another large low-risk trial found no statistically significant difference between surgery and usual conservative care on any primary outcome at 1 and 2 years
- Data were not pooled because of clinical heterogeneity and poor reporting
Clinical Implication: Surgery accelerates recovery but does not alter the favourable natural history. It is indicated for quality of life and faster return to function when conservative measures fail.
Limitation: Marked clinical heterogeneity, varied surgical techniques and conservative protocols precluded meta-analysis; future work should identify who benefits most from each pathway.
Fragment Type, Anular Competence and Reherniation after Discectomy
Carragee EJ, Han MY, Suen PW, Kim D • J Bone Joint Surg Am (2003)
Key Findings:
- Prospective study of 187 patients undergoing single-level primary discectomy, classified by intra-operative fragment type and anular defect
- Fragment-Fissure herniations (fragment with small anular defect) had the best outcomes and lowest reherniation (1%) and reoperation (1%) rates
- Fragment-Defect herniations (extruded fragment with massive posterior anular loss) had high reherniation (27%) and reoperation (21%) rates
- No Fragment-Contained herniations did poorly: 38% had recurrent or persistent sciatica
- Intra-operative anular competence predicted outcome better than demographic or clinical variables
Clinical Implication: A large/incompetent anular defect is the dominant predictor of reherniation. Preserving the anulus and removing only loose fragment material, alongside lifestyle modification (smoking cessation, avoid heavy lifting), is the rational strategy.
Limitation: Single-surgeon series; fragment classification depends on intra-operative assessment and may limit generalisability.
Non-operative Treatment of Herniated Lumbar Disc with Radiculopathy
Saal JA, Saal JS • Spine (Phila Pa 1976) (1989)
Key Findings:
- Cohort of 64 patients with CT-confirmed herniated nucleus pulposus, radicular leg pain, positive SLR and EMG-confirmed radiculopathy, treated with an aggressive rehabilitation programme
- 90% achieved a good or excellent outcome with a 92% return-to-work rate at a mean 31-month follow-up
- Patients with extruded discs did well (87% good/excellent), supporting a favourable non-operative course even for larger herniations
- Only a small minority required surgery, and 4 of 6 of those were found to have stenosis at operation
- Results compared favourably with contemporary surgical series
Clinical Implication: Natural history favours resolution with structured non-operative care, which is first-line. Even extruded fragments frequently improve without surgery.
Limitation: Retrospective single-centre cohort with no control group and selection bias; the intensive rehabilitation protocol is not universally available.
Early Surgery vs Prolonged Conservative Care for Sciatica (Leiden RCT)
Peul WC, van Houwelingen HC, van den Hout WB et al • N Engl J Med (2007)
Key Findings:
- RCT of 283 patients with 6-12 weeks of severe sciatica randomised to early surgery vs prolonged conservative care with surgery if needed
- 89% of the early-surgery arm had microdiscectomy (mean 2.2 weeks); 39% of the conservative arm crossed over to surgery (mean 18.7 weeks)
- Relief of leg pain and perceived recovery were significantly faster with early surgery (recovery hazard ratio 1.97, 95% CI 1.72-2.22)
- No significant overall difference in disability scores during the first year; probability of perceived recovery at 1 year was 95% in both arms
- Two-year follow-up (Peul WC et al, BMJ 2008, PMID 18502911) confirmed equivalent outcomes by 1-2 years
Clinical Implication: Early surgery delivers faster relief and recovery but the same outcome by 1-2 years. The choice is preference-sensitive: it shortens suffering for severely affected patients but is not required, since most recover with continued conservative care.
Limitation: Dutch healthcare setting (ready surgical access) and high planned crossover; reflects a structured care pathway rather than surgery-versus-no-surgery.
Imaging Findings of Spine Degeneration in Asymptomatic Populations
Brinjikji W, Luetmer PH, Comstock B et al • AJNR Am J Neuroradiol (2014)
Key Findings:
- Systematic review of 33 studies and 3110 asymptomatic individuals quantifying degenerative imaging findings by age
- Disc bulge prevalence rose from 30% at age 20 to 84% at age 80; disc protrusion from 29% to 43%
- Disc degeneration was present in 37% of 20-year-olds and 96% of 80-year-olds
- Annular fissures were present in 19-29% of asymptomatic individuals across ages
- Many degenerative features are part of normal ageing and unassociated with pain
Clinical Implication: Imaging findings are extremely common in pain-free people, so MRI must be correlated with the clinical picture. Never operate on imaging alone; the symptomatic level must match the examination.
Limitation: Pooled prevalence from heterogeneous study designs and imaging protocols; modality (CT vs MRI) and definitions varied between included studies.
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
CLINICAL SCENARIOStandard
Scenario 1: Classic L5 Radiculopathy
CLINICAL PROMPT
"A 45-year-old manual laborer presents with 8 weeks of right leg pain radiating to the dorsum of the foot. Pain is worse than back pain, aggravated by sitting and coughing. On examination, he has weak ankle dorsiflexion (EHL grade 3/5), numbness in the first web space, and positive straight leg raise at 40 degrees. MRI shows a right paracentral disc herniation at L4-L5 compressing the L5 nerve root. What is your assessment and management?"
PRACTICAL APPROACH
This gentleman has a **right L5 radiculopathy** secondary to a paracentral L4-L5 disc herniation. The clinical and radiological findings are concordant. **Clinical Assessment:** The key features are: - **Radicular pain worse than back pain** - this is classic for disc herniation - **L5 dermatomal distribution** - dorsum of foot, first web space - **L5 motor weakness** - EHL weakness (grade 3/5), ankle dorsiflexion - **Positive SLR at 40 degrees** - highly suggestive of nerve root compression - **MRI correlation** - L4-L5 disc herniation compressing the L5 traversing root **Management:** He has had 8 weeks of symptoms, which suggests he has **failed initial conservative management**. However, I would first ensure he has had adequate conservative care: - **Medical management**: NSAIDs, neuropathic agents (gabapentin or pregabalin) - **Physiotherapy**: Core strengthening, nerve glides, posture education - **Activity modification**: Avoid heavy lifting, prolonged sitting Given the **progressive motor weakness** (EHL grade 3/5), I would discuss surgical options. Motor deficit is a relative indication for earlier surgery to prevent permanent footdrop. **Surgical Option:** I would offer **microdiscectomy** at the L4-L5 level: - **Approach**: Posterior midline or paramedian incision - **Technique**: Remove herniated fragment, decompress L5 nerve root, preserve disc height - **Goals**: Decompress nerve root, improve leg pain (may not fully restore motor function) - **Outcomes**: 85-90% good results for leg pain, motor recovery variable depending on duration **Consent Discussion:** - **Benefits**: Leg pain relief, prevent further motor deterioration - **Risks**: Recurrence (5-10%), dural tear (1-2%), infection (1-2%), nerve injury (less than 1%) - **Realistic expectations**: Leg pain improves, motor recovery may be incomplete, back pain may persist I would also counsel about **postoperative rehabilitation** (early mobilization, core strengthening) and **lifestyle modification** (smoking cessation, weight management, proper lifting technique) to reduce recurrence risk.
KEY CLINICAL POINTS
L5 radiculopathy from L4-L5 disc herniation (traversing root)
Clinical features: EHL weakness, first web space numbness, positive SLR
MRI confirms diagnosis and matches clinical level
Failed 8 weeks conservative care - surgical option appropriate
Progressive motor deficit is a relative indication for earlier surgery
Microdiscectomy is the gold standard surgical treatment
Remove herniated fragment, decompress nerve root, preserve disc height
Realistic expectations: leg pain relief, motor recovery variable, back pain may persist
Consent includes recurrence risk (5-10%), dural tear (1-2%), infection (1-2%)
Postoperative: early mobilization, core strengthening, lifestyle modification
COMMON PITFALLS
Operating based on MRI alone without clinical correlation
Not assessing adequacy of conservative management
Promising full motor recovery (EHL weakness may not fully resolve)
Not counseling about recurrence risk and prevention
Not addressing back pain expectations (microdiscectomy treats leg pain)
FURTHER QUESTIONS
"How would you perform the microdiscectomy? Walk me through the steps."
"The patient asks about recurrence - what do you tell him?"
"What would you do if you encountered a dural tear intraoperatively?"
CLINICAL SCENARIOChallenging
Scenario 2: Cauda Equina Syndrome
CLINICAL PROMPT
"A 55-year-old woman presents to ED with 48 hours of bilateral leg weakness, numbness around her perineum, and urinary retention requiring catheterization. She has a background of chronic low back pain and left leg sciatica for 6 months. On examination, she has bilateral ankle dorsiflexion weakness (grade 3/5), absent ankle jerks, saddle anesthesia, and reduced anal tone. How do you assess and manage this patient?"
PRACTICAL APPROACH
This is a **cauda equina syndrome** presenting as a surgical emergency. I would take immediate action. **Immediate Assessment:** The red flag features are: - **Saddle anesthesia** - perianal and perineal numbness - **Urinary retention** - requiring catheterization - **Bilateral leg symptoms** - bilateral weakness and sensory changes - **Reduced anal tone** - indicates cauda equina involvement This is **cauda equina syndrome** until proven otherwise, and requires **urgent imaging and emergency decompression**. **Immediate Management (within hours):** **Step 1: Clinical Assessment** - **Detailed neurological exam**: Document motor, sensory, reflexes, rectal exam (tone, perianal sensation) - **Bladder function**: Assess for urinary retention (already catheterized), overflow incontinence - **Bowel function**: Assess for fecal incontinence or constipation - **Timing**: Document when symptoms started (critical for prognosis) **Step 2: Urgent MRI Lumbar Spine** - **Within 1-2 hours** - this is an emergency investigation - **Look for**: Massive central disc herniation, epidural mass, spinal canal stenosis - **Exclude**: Epidural abscess, hematoma, tumor (require different management) **Step 3: Emergency Decompression** If MRI confirms cauda equina compression from disc herniation: - **Timing**: Emergency surgery **within 24-48 hours** (sooner is better) - **Approach**: Bilateral laminectomy at affected level(s) to decompress cauda equina - **Technique**: Wide decompression, remove compressing disc fragments, decompress all affected nerve roots - **Goals**: Prevent permanent bowel/bladder dysfunction, maximize neurological recovery **Surgical Details:** - **Anesthesia**: General anesthesia, patient already catheterized - **Position**: Prone on Wilson frame, abdominal decompression - **Incision**: Midline incision, wider exposure than standard microdiscectomy - **Decompression**: Bilateral laminectomy (not just hemilaminotomy), remove ligamentum flavum, decompress dural sac - **Disc removal**: Remove all compressing disc fragments centrally, may need to explore both sides - **Confirmation**: Dural sac should be lax, pulsatile, nerve roots mobile **Prognosis Discussion:** - **Timing is critical**: Surgery within 48 hours gives best chance of recovery - **Bladder recovery**: 50-70% regain normal function if operated within 48 hours - **Motor recovery**: Often incomplete, depends on severity and duration - **Permanent dysfunction possible**: May have residual bowel/bladder issues - **Realistic expectations**: Even with emergency surgery, full recovery is not guaranteed **Postoperative Management:** - **Catheter**: May need to remain for days to weeks until bladder function recovers - **Bowel regimen**: Manage constipation, educate about bowel care - **Urodynamics**: Follow-up assessment if bladder dysfunction persists - **Physiotherapy**: Intensive rehab for motor recovery - **MDT approach**: Urology, spinal surgeon, physio, OT involvement
KEY CLINICAL POINTS
Cauda equina syndrome is a surgical EMERGENCY
Red flags: saddle anesthesia, urinary retention, bilateral leg symptoms, reduced anal tone
Urgent MRI within 1-2 hours to confirm diagnosis
Emergency decompression within 24-48 hours (sooner is better)
Wide bilateral laminectomy, remove all compressing disc fragments
Prognosis depends on timing - operate as soon as possible
50-70% bladder recovery if surgery within 48 hours
Realistic expectations - full recovery not guaranteed even with emergency surgery
Postoperative: may need prolonged catheterization, bowel regimen, intensive rehab
MDT approach involving urology, spinal surgeon, physiotherapy
COMMON PITFALLS
Delaying MRI or surgery (every hour counts)
Performing standard microdiscectomy instead of wide decompression
Not documenting baseline function (medico-legal)
Promising full recovery (realistic expectations critical)
Not involving MDT (urology, OT, physio) postoperatively
FURTHER QUESTIONS
"What is the prognosis if surgery is delayed beyond 48 hours?"
"How would you counsel the patient preoperatively about outcomes?"
"What would you do differently if MRI showed an epidural abscess instead of disc herniation?"
CLINICAL SCENARIOCritical
Scenario 3: Recurrent Disc Herniation
CLINICAL PROMPT
"A 38-year-old man presents with recurrent right L5 radiculopathy 18 months after successful microdiscectomy at L4-L5. He had complete resolution of leg pain after the initial surgery and returned to his job as a builder. The pain recurred 2 weeks ago after lifting a heavy object at work. MRI shows a recurrent right paracentral disc herniation at L4-L5. He asks what went wrong and what can be done. How do you manage this?"
PRACTICAL APPROACH
This is a case of **recurrent lumbar disc herniation** at the same level (L4-L5) 18 months after primary microdiscectomy. I need to address both the patient's concerns about why this happened and the management options. **Discussion of Recurrence:** I would have a transparent conversation with the patient: "I understand your concern. Recurrent disc herniation occurs in **5-10% of patients** after microdiscectomy. This is not a failure of the surgery - your initial surgery was successful (complete pain relief). What has happened is that **another fragment from the same disc has herniated**, likely related to the heavy lifting incident." **Why Recurrence Happens:** - **Disc degeneration is progressive**: The disc that herniated once is weakened and prone to further herniation - **Biomechanical stress**: Your occupation (builder) involves heavy lifting and repetitive loading - **Large annular defect**: The original herniation left a defect in the disc annulus - **Risk factors**: Smoking (if applicable), age (young patients have more nucleus material), heavy occupation "The good news is that recurrent herniations can be treated successfully, though the outcomes are slightly less predictable than primary surgery." **Management Options:** **Option 1: Conservative Management (First-Line)** - **Try conservative care first** - same as primary herniation - **Medical management**: NSAIDs, neuropathic agents - **Physiotherapy**: Core strengthening, activity modification - **Nerve root injection**: Diagnostic and therapeutic - **Duration**: 6 weeks trial **Rationale**: Some recurrent herniations resolve spontaneously (same natural history as primary), and reoperation carries slightly higher risks (scar tissue, dural adhesions). **Option 2: Revision Microdiscectomy** If conservative care fails after 6 weeks: - **Approach**: Same posterior approach, more challenging due to scar tissue - **Technique**: Careful dissection through scar, identify anatomy, remove recurrent fragment - **Considerations**: Higher risk of dural tear (5-10% vs 1-2%), nerve root injury - **Outcomes**: 70-80% good results (slightly lower than primary surgery) **Option 3: Fusion (Not First-Line)** - **Indication**: Only if multiple recurrences, instability, or severe disc degeneration - **Technique**: Remove disc entirely, insert cage, posterior instrumentation - **Considerations**: More invasive, longer recovery, adjacent segment disease risk - **Reserve for**: Failed revision microdiscectomy or documented instability **My Recommendation for This Patient:** I would recommend: 1. **Initial conservative care (6 weeks)** - rule out spontaneous resolution 2. **If failed**: Revision microdiscectomy 3. **Counsel about risks**: Higher dural tear risk, scar tissue, outcomes slightly less predictable 4. **Lifestyle modification**: Discuss occupational change (avoid heavy lifting long-term) 5. **Smoking cessation**: If applicable - impairs healing and increases recurrence **Preventing Further Recurrence:** - **Occupational modification**: Consider changing to lighter duties, avoid repetitive heavy lifting - **Core strengthening**: Physiotherapy to strengthen lumbar spine support - **Smoking cessation**: If applicable - **Weight management**: Reduce biomechanical load - **Proper lifting technique**: Educate about safe manual handling **Realistic Expectations:** - **Success rate**: 70-80% for revision surgery (vs 85-90% for primary) - **Recurrence risk**: Slightly higher after revision (10-15%) - **Alternative**: If multiple recurrences, may need to consider fusion - **Occupation**: May need to consider career change if heavy manual work
KEY CLINICAL POINTS
Recurrent disc herniation occurs in 5-10% after microdiscectomy
Not a surgical failure - disc degeneration is progressive
Risk factors: heavy occupation, smoking, large annular defect, young age
Conservative management first - same natural history as primary herniation
Revision microdiscectomy if failed conservative care (6 weeks)
Revision surgery has higher risks: dural tear (5-10%), scar tissue, nerve injury
Outcomes slightly lower than primary surgery (70-80% vs 85-90%)
Fusion is NOT first-line - reserve for multiple recurrences or instability
Lifestyle modification critical: occupational change, smoking cessation, core strengthening
Realistic expectations about success rate and further recurrence risk
COMMON PITFALLS
Promising same outcomes as primary surgery (outcomes are slightly worse)
Not trying conservative care first (some recurrences resolve spontaneously)
Rushing to fusion (not indicated for first recurrence)
Not addressing occupational risk factors (heavy manual work)
Not counseling about higher surgical risks (dural tear, scar tissue)
FURTHER QUESTIONS
"What are the indications for fusion after recurrent disc herniation?"
"How would you minimize the risk of dural tear during revision surgery?"
"If the patient had three recurrences, what would you recommend?"
MCQ Practice Points
Anatomy Question
Q: An L4-L5 disc herniation typically compresses which nerve root? A: L5 nerve root (the traversing root). Lumbar nerve roots exit BELOW their corresponding pedicle. At L4-L5 level, the L4 root has already exited, and the L5 root crosses the disc space in the lateral recess. Far lateral herniations at L4-L5 level would compress the exiting L4 root.
Clinical Diagnosis Question
Q: What is the most specific clinical sign for lumbar disc herniation? A: Crossed straight leg raise (raising the unaffected leg reproduces pain in the symptomatic leg). This has 95% specificity for disc herniation. Standard SLR has high sensitivity (90%) but low specificity (25%).
Imaging Question
Q: When is MRI indicated for acute sciatica? A: MRI is NOT needed in the first 6 weeks unless red flags are present (cauda equina, progressive motor deficit, bilateral symptoms, severe or rapidly worsening pain). 90% of disc herniations resolve with conservative care, and MRI findings do not change initial management. MRI is indicated if considering surgery after failed conservative care.
Management Question
Q: What is the evidence for surgery vs conservative care for lumbar disc herniation? A: SPORT trial showed that surgery provides faster pain relief, but outcomes at 4 years are similar between surgical and conservative groups due to high crossover rate (50% of conservative patients eventually had surgery). Surgery is indicated for quality of life and faster return to function, NOT superior long-term outcomes. Natural history favors spontaneous resolution.
Surgical Indication Question
Q: What are the absolute indications for surgery in lumbar disc herniation? A: Cauda equina syndrome is the only absolute indication (emergency surgery within 24-48 hours). Progressive motor deficit (e.g., worsening foot drop) is a relative indication for earlier surgery. Failed conservative care (6 weeks) with persistent disabling symptoms is an elective indication. Predominant back pain alone is NOT an indication for microdiscectomy.
Complication Question
Q: What is the most common complication after microdiscectomy? A: Recurrent disc herniation (5-10% within 2 years). Risk factors include large annular defect, smoking, heavy occupation, young age. Aggressive discectomy (removing all nucleus) does NOT reduce recurrence rate. Revision surgery is performed if conservative management fails for recurrence.
Guidelines, Registries & Global Practice
Global epidemiology:
- Lifetime sciatica affects roughly 10-40% of adults depending on definition; symptomatic lumbar disc herniation peaks at 30-50 years with a modest male predominance.
- Asymptomatic findings are the norm with age: in a systematic review of 3110 pain-free people, disc bulges were present in 30% at age 20 rising to 84% at age 80 (Brinjikji W et al, AJNR 2014, PMID 25430861) — the evidence base for insisting on clinical-radiological correlation.
- Burden: low back pain and radiculopathy are consistently among the leading global causes of years lived with disability, driving high rates of imaging, injection and surgery worldwide.
Side-by-side guideline guidance:
International Guidance on Sciatica / Lumbar Disc Herniation
| Body (region) | Imaging | Conservative first? | Surgery threshold | Evidence emphasis |
|---|---|---|---|---|
| NICE NG59 (UK) | No routine early MRI; image only if it would change management | Yes - exercise, self-management, avoid bed rest | Refer for spinal opinion if radicular pain persists despite non-surgical care | Strong steer against early imaging and opioids |
| AAOS / NASS (USA) | MRI is the imaging of choice when surgery considered | Yes for 6 weeks unless red flags | Discectomy for persistent radiculopathy concordant with imaging after failed conservative care | SPORT-informed shared decision-making |
| BOA / BASS (UK) | Urgent MRI for suspected cauda equina; otherwise after failed conservative care | Yes | Emergency decompression for CES; elective microdiscectomy for failed conservative care | Cauda equina pathway and timely MRI |
| EFORT / European spine societies | MRI to confirm level before surgery | Yes; epidural steroid injection as an option | Microdiscectomy when disabling radiculopathy persists | Aligns with Peul and Jacobs evidence |
Where Guidelines Agree
Across NICE, AAOS/NASS, BOA/BASS and European bodies the message is consistent: conservative care first for around 6 weeks, no routine early MRI, image only when it will change management, and reserve surgery for cauda equina, progressive deficit, or concordant radiculopathy that fails conservative treatment. Disagreement is mainly about the role and timing of epidural steroid injection.
Registry and outcome evidence:
- Spine registries (e.g. the UK British Spine Registry, the Swedish Swespine register, the Norwegian NORspine register and similar national datasets) collect patient-reported outcomes (ODI, leg-pain VAS, EQ-5D) before and after lumbar discectomy. They consistently report large early improvements in leg pain and function and reoperation/reherniation rates broadly in line with the trial literature (around 5-10% within 2 years).
- Registry data are observational and used for benchmarking and case-mix-adjusted comparison rather than establishing efficacy, which rests on the randomised evidence (SPORT, Peul/Leiden).
Practice variation:
- Surgical rates vary several-fold between countries and regions, driven by access, reimbursement model, surgeon supply and patient preference rather than disease prevalence — a classic example of preference-sensitive care highlighted by SPORT.
- Injection use (transforaminal epidural steroid) varies widely; offered routinely in some systems and reserved for diagnostic or bridging use in others.
- Australian context: disc herniation is a leading reason for spine referral; elective microdiscectomy waiting times are longer in the public system than the private sector, and work-related lifting injuries commonly involve workers' compensation (WorkCover) pathways with structured return-to-work planning. Smoking cessation support (e.g. Quitline) is relevant given smoking's association with recurrence.
Medicolegal Considerations:
Documentation is Critical
Key documentation requirements:
- Pre-operative: Document failed conservative care (6 weeks physio, medications, injections), informed consent including recurrence risk
- Intra-operative: Level confirmation (fluoroscopy images), nerve root decompression achieved, any complications (dural tear)
- Post-operative: Immediate motor/sensory exam, discharge planning, follow-up arrangements
- Cauda equina cases: Time of symptom onset, time of MRI, time to theatre - timing is medicolegally scrutinized
Common litigation issues:
- Wrong level surgery: Always confirm level with fluoroscopy (never event)
- Delayed cauda equina surgery: Document time of presentation, MRI, and surgery; delays beyond 48 hours are scrutinized
- Informed consent: Discuss recurrence risk, persistent pain, nerve injury - document in notes
- Nerve root injury: Rare but serious; ensure gentle technique, document any intraoperative concerns
Occupational considerations:
- Return to work planning: Discuss with patient and employer; may need modified duties
- WorkCover claims: Coordinate with insurer, functional capacity assessment
- Vocational rehabilitation: Consider referral if unable to return to previous occupation
LUMBAR DISC HERNIATION
Clinical summary
Key Anatomy
- •Nucleus pulposus = 80% water, proteoglycans, type II collagen
- •Annulus fibrosus = type I collagen, posterolateral region thinnest
- •PLL weak laterally = posterolateral herniation in 95%
- •L4-L5 disc compresses L5 root (traversing), L4 root already exited
- •Cauda equina starts below conus (L1-L2 level), ends at S1-S2
Classification
- •Protrusion = base wider than dome, contained
- •Extrusion = base narrower than dome, through annulus
- •Sequestration = fragment separated, free in canal, best prognosis
- •Paracentral = most common (70%), compresses traversing root
- •Far lateral = compresses exiting root, needs different approach
Clinical Diagnosis
- •Radicular pain worse than back pain = hallmark feature
- •SLR positive if leg pain at less than 60 degrees (not back pain)
- •Crossed SLR = 95% specificity for disc herniation
- •L5: EHL weakness, first web space numbness, no reflex
- •S1: Plantar flexion weakness, lateral foot numbness, absent ankle jerk
- •Cauda equina = saddle anesthesia + bowel/bladder + bilateral symptoms
Management Algorithm
- •Conservative first (6 weeks) unless red flags - 90% improve
- •MRI only after 6 weeks or if red flags present
- •Surgery for: CES (emergency), progressive motor deficit, failed conservative care
- •Microdiscectomy = remove fragment, preserve disc height, early mobilization
- •Never operate on imaging alone - must match clinical findings
Surgical Technique
- •Confirm level with fluoroscopy before incision
- •Interlaminar window: remove ligamentum flavum, expose nerve root
- •Gentle nerve retraction - never pull forcefully
- •Remove loose fragments only - do not excise entire disc
- •Valsalva before closure to check for dural tear
- •Early mobilization - discharge same day or next day
Outcomes and Evidence
- •85-90% good outcomes for leg pain (back pain may persist)
- •Recurrence rate 5-10% at 2 years
- •SPORT trial: surgery faster relief, similar 4-year outcomes to conservative care
- •CES: Operate within 24-48h for best bladder recovery (50-70%)
- •Revision surgery: 70-80% success (vs 85-90% primary)
- •Fusion NOT indicated for first recurrence