Failed Back Surgery Syndrome
FAILED BACK SURGERY SYNDROME (FBSS)
Persistent or recurrent pain following anatomically successful lumbar spine surgery
FBSS Classification
Critical Must-Knows
- FBSS is a diagnosis of exclusion - must rule out infection, instability, recurrence
- Most common causes: Wrong diagnosis, inadequate decompression, recurrent pathology
- MRI with gadolinium: Scar (peripheral enhancement) vs recurrent disc (central mass)
- Multidisciplinary approach: Pain management, physical therapy, psychological support
- Spinal cord stimulation provides 50% pain reduction in selected patients
Examiner's Pearls
- "FBSS is NOT a specific diagnosis - it's a syndrome requiring systematic evaluation
- "Prevention is key: Correct diagnosis, appropriate surgery, proper level verification
- "Psychosocial factors strongly predict FBSS - screen preoperatively
- "Multiple surgeries worsen outcomes - avoid 'the next operation syndrome'
Clinical Imaging
Imaging Gallery




High-Yield Exam Points
Critical Distinction
FBSS vs Surgical Failure: FBSS occurs despite anatomically successful surgery. True surgical failure (wrong level, incomplete decompression, instrument failure) requires different management. Always verify surgical success first!
MRI Enhancement Pattern
Scar vs Recurrence: Epidural scar enhances on EARLY post-gadolinium images (under 5 minutes) with PERIPHERAL pattern. Recurrent disc shows DELAYED central enhancement or NO enhancement. This is the gold standard imaging distinction!
Prevention Strategies
Best Treatment is Prevention: Correct preoperative diagnosis, verify surgical level intraoperatively, avoid over-fusion, preserve posterior structures when possible, manage patient expectations, screen for psychosocial risk factors.
Revision Surgery Indications
Very Selective: Only consider revision if clear structural pathology (recurrent disc, inadequate decompression, instability), failed conservative care 6-12 months, and favorable psychosocial profile. Outcomes worsen with each reoperation!
At a Glance
Failed back surgery syndrome (FBSS) is persistent or recurrent pain following anatomically successful lumbar spine surgery, affecting 10-40% of patients. It is a diagnosis of exclusion—common causes include epidural fibrosis (scar tissue tethering nerve roots), wrong level surgery (15-20%), inadequate decompression, and recurrent disc herniation. MRI with gadolinium distinguishes scar (peripheral enhancement under 5 min) from recurrent disc (delayed/central enhancement). Management is multidisciplinary: conservative rehabilitation, interventional pain procedures, and spinal cord stimulation (50% pain reduction in selected patients). Revision surgery has diminishing returns with each operation and is reserved for clear structural pathology with favourable psychosocial profile.
FAILEDFBSS Common Causes
Memory Hook:Why the back surgery FAILED!
SCARSFBSS Evaluation Algorithm
Memory Hook:Look for SCARS as causes of persistent pain!
PREVENTPrevention Strategies
Memory Hook:How to PREVENT FBSS in the first place!
Overview and Definition
Failed back surgery syndrome (FBSS) represents one of the most challenging complications in spine surgery. The term encompasses a heterogeneous group of patients with persistent or recurrent pain following technically successful lumbar spine operations.
Definition and Terminology
Failed Back Surgery Syndrome (FBSS)
- Persistent or recurrent low back and/or leg pain following lumbar spine surgery
- Occurs despite anatomically successful surgical procedure
- Symptoms present beyond expected recovery period (typically 3-6 months)
- Also termed "post-laminectomy syndrome" or "persistent spinal pain syndrome type 2"
Key Distinction
- FBSS: Anatomically successful surgery with persistent symptoms
- Surgical Failure: Technical failure (wrong level, incomplete decompression, hardware failure)
Epidemiology
Incidence and Prevalence
| Parameter | Value | Notes |
|---|---|---|
| Overall incidence | 10-40% post-lumbar surgery | Varies by indication and technique |
| Post-discectomy | 5-15% | Lower rate with minimally invasive techniques |
| Post-laminectomy | 10-30% | Higher with extensive decompressions |
| Post-fusion | 15-40% | Highest rates with multi-level fusion |
| Prevalence in pain clinics | 20-25% of referrals | Major burden on healthcare system |
Risk Factors for FBSS
| Category | Risk Factors |
|---|---|
| Patient factors | Smoking, obesity, poor conditioning, workers' compensation, litigation |
| Psychological | Depression, anxiety, catastrophizing, poor coping strategies |
| Surgical | Wrong level, inadequate decompression, excessive tissue damage |
| Disease-related | Multi-level disease, severe degeneration, instability |
| Postoperative | Delayed mobilization, inadequate rehabilitation, poor compliance |
Exam Pearl
Psychosocial factors are the strongest predictors of FBSS development. Depression, catastrophizing, and poor coping predict outcomes more strongly than surgical technique. Preoperative psychological screening is essential!
Pathophysiology
Understanding the causes of FBSS is critical for both prevention and management. Causes can be broadly categorized into technical, biological, and psychological factors.
Etiology
Technical Causes
Wrong Level Surgery
Epidemiology
- Incidence: 5-15% of primary operations
- More common in obesity, anatomical variants
- Preventable with proper technique
Contributing Factors
| Factor | Impact |
|---|---|
| Anatomical variants | Transitional vertebrae, six lumbar vertebrae |
| Counting error | Starting from wrong reference point |
| Imaging correlation | Failure to verify level intraoperatively |
| Obesity | Difficulty palpating landmarks |
Prevention
- Count from sacrum upward (most reliable)
- Obtain intraoperative imaging before incision
- Use radiopaque marker on skin over planned level
- Verify with AP and lateral fluoroscopy
- Document level verification in operative note
Wrong-site surgery is a never event! Always verify level with imaging before incision. Mark the skin with a radiopaque marker, obtain AP and lateral films, and document verification before proceeding.
This completes the wrong level surgery discussion.
Biological Causes
Epidural Fibrosis (Scar Tissue)
The most common cause of FBSS, occurring in 5-60% of postoperative patients.
| Aspect | Details |
|---|---|
| Pathophysiology | Excessive scar formation tethering nerve roots |
| Timeline | Develops 3-6 months postoperatively |
| Symptoms | Radicular pain, worse with activity, burning quality |
| MRI appearance | Peripheral enhancement on early gadolinium images |
| Treatment | Conservative management, epidural injections, consider adhesiolysis |
Recurrent Disc Herniation
| Parameter | Details |
|---|---|
| Incidence | 5-15% following discectomy |
| Timeline | Can occur early (under 3 months) or late (over 2 years) |
| Risk factors | Large annular defect, smoking, young age, heavy labor |
| Symptoms | Radicular pain, often sudden onset with activity |
| Differentiation | MRI with gadolinium (no enhancement or delayed central) |
Scar Tissue vs Recurrent Disc Herniation
| Feature | Epidural Fibrosis (Scar) | Recurrent Disc Herniation |
|---|---|---|
| Timeline | 3-6 months post-op | Variable, often sudden |
| Pain onset | Gradual | Often acute with activity |
| Pain character | Burning, aching | Sharp, radiating |
| MRI T1 pre-contrast | Intermediate signal | Hypointense |
| MRI T2 | Variable signal | Hyperintense |
| Gadolinium enhancement | EARLY peripheral enhancement | NO enhancement or DELAYED central |
| Mass effect | Minimal | Moderate to severe |
| Surgical treatment | Generally ineffective | May benefit from revision |
Adjacent Segment Disease
Degeneration at levels adjacent to fusion, occurring in 5-25% by 10 years.
| Feature | Description |
|---|---|
| Mechanism | Increased stress on adjacent mobile segments |
| Risk factors | Long fusion construct, sagittal malalignment, preexisting degeneration |
| Symptoms | New onset back/leg pain at new dermatomal level |
| Imaging | Disc degeneration, stenosis at adjacent level |
| Management | Initially conservative; consider extension of fusion if severe |
Arachnoiditis
Inflammatory reaction causing nerve root clumping and scarring.
| Aspect | Details |
|---|---|
| Incidence | Rare (under 5%), more common with multiple surgeries |
| Causes | Intrathecal blood, infection, myelography contrast (historical) |
| MRI findings | Clumped nerve roots, "empty thecal sac" sign, central cord |
| Prognosis | Generally poor, progressive symptoms |
| Management | Pain management, avoid further surgery |
Exam Pearl
MRI gadolinium timing is critical: Scar enhances EARLY (under 5 minutes) with PERIPHERAL pattern. Recurrent disc shows NO enhancement or DELAYED CENTRAL enhancement. Always specify timing of post-contrast imaging!



Psychological Factors
Central Sensitization
Maladaptive neuroplastic changes resulting in chronic pain syndrome.
| Feature | Description |
|---|---|
| Mechanism | Altered CNS pain processing, lowered pain threshold |
| Symptoms | Widespread pain, hyperalgesia, allodynia |
| Diagnosis | Clinical diagnosis, often disproportionate to pathology |
| Treatment | Multidisciplinary pain program, medications, CBT |
Psychosocial Risk Factors
The "Yellow Flags" predicting poor outcomes:
- Depression and anxiety
- Catastrophizing and fear-avoidance beliefs
- Poor coping strategies
- Secondary gain (compensation, litigation)
- Job dissatisfaction
- Social isolation
Clinical Assessment
Systematic evaluation is essential to identify treatable causes and guide management.
History
Pain Characterization
| Question | Purpose |
|---|---|
| Timeline | When did symptoms start relative to surgery? |
| Pain-free interval | Any relief post-surgery before recurrence? |
| Location | Back predominant, leg predominant, or equal? |
| Character | Sharp/shooting (nerve) vs aching/burning (scar/chronic)? |
| Aggravating factors | Positional, activity-related, constant? |
| Relieving factors | Rest, position changes, medications? |
Red Flags Requiring Urgent Evaluation
Immediate investigation required:
- New onset bowel/bladder dysfunction (cauda equina)
- Progressive motor weakness
- Fever, wound drainage (infection)
- Severe unremitting pain unresponsive to medications
- New sensory level (thoracic symptoms)
Functional Assessment
- Walking distance and tolerance
- Sleep disruption
- Activities of daily living impact
- Work status and disability
- Medication requirements and escalation
- Previous pain management interventions
Psychosocial Screening
Use validated tools:
- Oswestry Disability Index (ODI)
- Visual Analog Scale (VAS) for pain
- SF-36 for quality of life
- Depression screening (PHQ-9)
- Opioid Risk Tool (ORT)
Physical Examination
Inspection
- Surgical scar assessment (well-healed, keloid, drainage)
- Spinal alignment (coronal and sagittal balance)
- Gait pattern and assistive devices
- Muscle wasting in affected myotome
Palpation
- Tenderness over surgical site
- Paraspinal muscle spasm
- Trigger points
- Sacroiliac joint assessment
Range of Motion
- Lumbar flexion and extension
- Note pain reproduction with movement
- Assess for compensation patterns
Neurological Examination
| Component | Assessment | Significance |
|---|---|---|
| Motor | Myotomal strength testing | New weakness vs pre-existing deficit |
| Sensory | Dermatomal mapping | Compare to preoperative examination |
| Reflexes | Knee jerk (L4), ankle jerk (S1) | May be absent post-surgery |
| Tension signs | Straight leg raise, femoral stretch | Positive suggests neural irritation |
| Waddell signs | Non-organic signs | Over 3 suggests psychosocial component |
Vascular Examination
- Peripheral pulses (exclude vascular claudication)
- Skin changes, hair loss, temperature
- Ankle-brachial index if vascular suspected
Diagnostic Workup
Systematic imaging and diagnostic procedures to identify treatable pathology.
Imaging Protocol
MRI with Gadolinium Contrast
The gold standard for FBSS evaluation.
Sequences Required
| Sequence | Purpose |
|---|---|
| T1 pre-contrast | Baseline anatomy, fat signal |
| T2 sagittal/axial | Disc hydration, stenosis, neural compression |
| T1 post-gadolinium | Distinguish scar vs recurrent disc |
| Fat-suppressed post-contrast | Enhance inflammatory changes |
Interpretation - Scar vs Recurrence
| Feature | Epidural Scar | Recurrent Disc |
|---|---|---|
| Pre-contrast T1 | Intermediate signal | Hypointense |
| T2 signal | Variable | Hyperintense (if hydrated) |
| Post-gadolinium | EARLY peripheral enhancement | NO or DELAYED central enhancement |
| Enhancement timing | Under 5 minutes | Over 15 minutes or none |
| Mass effect | Minimal | Present |
| Nerve displacement | Tethering | Displacement away |
Other MRI Findings
- Arachnoiditis: Clumped nerve roots, empty thecal sac
- Pseudomeningocele: CSF collection, dural tear
- Infection: Disc signal change, endplate edema, enhancement
- Stenosis: Residual or adjacent level canal narrowing
This MRI protocol is essential for surgical planning and diagnostic accuracy.
Diagnostic Interventions
Selective Nerve Root Blocks
| Purpose | Technique | Interpretation |
|---|---|---|
| Diagnostic | Inject local anesthetic around suspected nerve root | Over 75% pain relief confirms level |
| Therapeutic | Add steroid for therapeutic effect | May provide temporary or prolonged relief |
| Surgical planning | Multi-level disease | Identify symptomatic level for decompression |
Facet Joint Injections/Medial Branch Blocks
- Identify facetogenic pain source
- May guide radiofrequency ablation
- Diagnostic response: Over 80% relief with local anesthetic
Discography (Controversial)
| Aspect | Details |
|---|---|
| Indication | Identify painful disc in multi-level disease |
| Technique | Provocative injection into disc nucleus |
| Positive test | Concordant pain reproduction at low pressure |
| Controversy | High false-positive rate, may accelerate degeneration |
| Current use | Limited; mostly for fusion planning in young patients |
Exam Pearl
Diagnostic blocks are valuable but not definitive. Placebo response rates are 30-40%. Confirmatory blocks with different local anesthetics (e.g., lidocaine then bupivacaine on separate days) increase specificity. Never operate based on blocks alone!
Management Algorithm

Treatment of FBSS requires a multidisciplinary, stepwise approach. Surgery is rarely first-line.
Conservative Management (First-Line)
Physical Therapy and Rehabilitation
Goals of Physical Therapy
- Restore function and mobility
- Strengthen core musculature
- Improve flexibility and posture
- Reduce fear-avoidance behaviors
- Facilitate return to activities
Program Components
| Phase | Duration | Focus |
|---|---|---|
| Phase 1 | Weeks 1-4 | Pain control, gentle ROM, posture |
| Phase 2 | Weeks 4-8 | Core strengthening, endurance training |
| Phase 3 | Weeks 8-12 | Functional activities, work simulation |
| Maintenance | Ongoing | Home exercise program, activity pacing |
Pharmacotherapy
Multimodal Analgesia Approach
| Class | Examples | Dosing | Considerations |
|---|---|---|---|
| NSAIDs | Ibuprofen, naproxen | As needed or scheduled | GI protection if chronic use |
| Acetaminophen | Paracetamol | 1g TDS-QID | Max 4g/day, hepatotoxicity risk |
| Neuropathic agents | Gabapentin, pregabalin | Titrate to effect | Sedation, dizziness common |
| Antidepressants | Duloxetine, amitriptyline | Start low, increase slowly | Dual benefit: pain and mood |
| Muscle relaxants | Cyclobenzaprine | Short-term use | Sedation, dependence risk |
| Topical agents | Lidocaine patches, capsaicin | Apply to painful area | Localized effect, fewer systemic side effects |
Opioids have LIMITED role in chronic FBSS: Evidence shows minimal benefit and high risk of dependence, hyperalgesia, and worsening outcomes. Avoid chronic opioid therapy when possible. If used, use structured agreement, monitor urine drug screens, assess using Opioid Risk Tool (ORT).
Psychological Interventions
Cognitive Behavioral Therapy (CBT)
| Component | Goal |
|---|---|
| Cognitive restructuring | Challenge catastrophizing, negative thoughts |
| Behavioral activation | Increase activity despite pain |
| Relaxation training | Reduce muscle tension, anxiety |
| Pacing strategies | Avoid boom-bust cycles |
| Sleep hygiene | Improve sleep quality |
Multidisciplinary Pain Rehabilitation Programs
Intensive programs combining physical therapy, psychological therapy, medication optimization, occupational therapy, and vocational rehabilitation show best long-term functional outcomes for FBSS patients.
Interventional Pain Management
Epidural Steroid Injections
| Approach | Indication | Success Rate | Duration |
|---|---|---|---|
| Interlaminar | Central stenosis, broad distribution | 30-50% improve | 3-6 months |
| Transforaminal | Radiculopathy, specific nerve root | 50-70% improve | 3-6 months |
| Caudal | Multi-level, previous surgery | 30-40% improve | Variable |
Radiofrequency Ablation
- Target: Facet joint medial branches or dorsal root ganglion
- Indication: Positive diagnostic blocks
- Duration: 6-12 months relief
- Repeatable if initial success
Neuromodulation
Spinal Cord Stimulation (SCS)
The most evidence-based intervention for FBSS with predominant leg pain.
Patient Selection Criteria
| Criterion | Details |
|---|---|
| Pain pattern | Predominantly radicular leg pain |
| Failed conservative care | At least 6 months appropriate treatment |
| Psychological screening | No untreated major depression, realistic expectations |
| No surgical indication | No correctable structural pathology |
| Trial success | Over 50% pain reduction during trial period |
Evidence Base
| Study | Findings |
|---|---|
| PROCESS trial | SCS superior to conventional management at 6 months |
| Long-term studies | 50-70% maintain over 50% pain reduction at 5 years |
| Patient satisfaction | 70-80% would repeat procedure |
| Functional improvement | Significant improvements in ODI, quality of life |
Exam Pearl
SCS is evidence-based for FBSS: PROCESS trial showed SCS superior to reoperation for FBSS with radicular pain. Trial before permanent implant is mandatory. Predominantly leg pain responds better than back pain!
Surgical Management (Highly Selective)
Indications for Revision Surgery
Surgery is rarely indicated in FBSS. Consider ONLY if ALL criteria met:
- Clear structural pathology on imaging (recurrent disc, stenosis, instability)
- Symptoms correlate with imaging findings
- Failed 6-12 months of appropriate conservative care
- Reasonable surgical target identified
- Favorable psychosocial profile
- Patient has realistic expectations
Specific Surgical Indications
| Pathology | Surgery | Expected Success Rate |
|---|---|---|
| Recurrent disc herniation | Revision discectomy ± fusion | 60-80% if clear recurrence |
| Inadequate decompression | Revision decompression | 50-70% if residual compression |
| Pseudarthrosis | Revision fusion | 50-60% (decreases with each revision) |
| Adjacent segment disease | Extension of fusion | 40-60% |
| Iatrogenic instability | Fusion | 50-70% |
Outcomes Decrease with Multiple Operations
| Number of Operations | Success Rate |
|---|---|
| Primary surgery | 70-90% |
| First revision | 50-70% |
| Second revision | 30-50% |
| Third or more | Under 30% |
Exam Pearl
The "next operation syndrome": Each subsequent operation has LOWER success rate and HIGHER complication rate. After 3 operations, success rate under 30%. Avoid perpetual surgical cycling - recognize when surgery will not help!
Prevention Strategies
The best treatment for FBSS is prevention. Systematic approach reduces incidence.
Preoperative Prevention
Correct Diagnosis
| Strategy | Implementation |
|---|---|
| Correlate symptoms with imaging | Ensure MRI findings explain clinical picture |
| Consider differential diagnoses | Hip pathology, peripheral neuropathy, vascular |
| Trial of conservative care | 6-12 weeks unless red flags |
| Avoid surgery for back pain alone | Poor outcomes without radiculopathy |
Patient Selection and Education
Psychosocial Screening
- Depression and anxiety screening (PHQ-9, GAD-7)
- Catastrophizing assessment
- Litigation and compensation status
- Substance abuse history
- Social support assessment
Realistic Expectations
- Discuss achievable outcomes (improvement, not perfection)
- Explain recovery timeline (3-6 months full recovery)
- Review risks and alternative treatments
- Document shared decision-making
Risk Factor Modification
- Smoking cessation: 4-6 weeks preoperatively
- Weight optimization if BMI over 35
- Diabetes control: HbA1c under 7.5%
- Optimize nutrition status
- Discontinue NSAIDs and anticoagulants per protocol
Intraoperative Prevention
Surgical Technique
| Principle | Implementation |
|---|---|
| Level verification | Imaging confirmation BEFORE incision |
| Adequate decompression | Decompress symptomatic levels completely |
| Preserve stability | Preserve under 50% of facet joints |
| Minimize tissue trauma | Use retractors judiciously, limit stripping |
| Hemostasis | Prevent hematoma formation |
| Dural repair | Watertight closure if dural tear occurs |
Specific Technical Points
Discectomy
- Remove loose fragments completely
- Avoid aggressive curettage of disc space
- Preserve annular integrity when possible
- Consider limited anular closure techniques
Decompression
- Decompress lateral recess adequately
- Undercut facet if foraminal stenosis
- Bilateral decompression for bilateral symptoms
- Preserve pars interarticularis
Fusion Decision
- Fuse if instability present (over 3-4mm translation)
- Fuse if over 50% facet resection required
- Consider fusion if degenerative spondylolisthesis
- Avoid unnecessary fusion (increases adjacent segment disease)
Exam Pearl
Level verification is NON-NEGOTIABLE: Always obtain AP and lateral intraoperative imaging BEFORE incision. Mark skin with radiopaque marker. Count from sacrum upward. Document verification in operative note. Wrong-site surgery is preventable!
Postoperative Prevention
Early Mobilization
| Timeline | Activity |
|---|---|
| Day 0-1 | Out of bed, walking with assistance |
| Week 1-2 | Independent ambulation, self-care |
| Week 2-6 | Progressive walking, light activities |
| Week 6-12 | Formal physical therapy, return to work (sedentary) |
Pain Management
- Multimodal analgesia (minimize opioids)
- Scheduled NSAIDs (if no contraindication)
- Neuropathic pain agents if radicular pain persists
- Transition to oral medications by discharge
Physical Therapy
- Early referral (week 2-4)
- Core strengthening program
- Flexibility and posture training
- Ergonomic education
Follow-up Protocol
- Week 2: Wound check, pain assessment
- Week 6: Clinical evaluation, consider imaging if concerns
- Month 3: Functional assessment
- Month 6 and 12: Long-term outcome evaluation
Complications
Understanding potential complications helps inform patient counseling and guide treatment decisions.
Complications of Conservative Treatment
Non-Interventional Complications
| Treatment | Complication | Incidence | Management |
|---|---|---|---|
| NSAIDs | GI bleeding, cardiovascular events | 1-5% with chronic use | PPI prophylaxis, lowest effective dose |
| Neuropathic agents | Sedation, dizziness, falls | 10-30% | Dose titration, fall precautions |
| Opioids | Dependence, hyperalgesia, constipation | 20-40% with chronic use | Avoid when possible, bowel regimen |
| Physical therapy | Acute injury, pain flare | Under 5% | Proper screening, gradual progression |
Psychological Intervention Risks
- Emotional distress during CBT (initial worsening)
- Resistance to treatment
- Time and financial commitment
- Generally safe with skilled practitioners
Complications of Interventional Procedures
Epidural Steroid Injections
| Complication | Incidence | Management |
|---|---|---|
| Dural puncture | 1-5% | Bed rest, blood patch if persistent headache |
| Infection (epidural abscess) | Under 1% | Emergency MRI, surgical drainage, IV antibiotics |
| Bleeding/hematoma | Under 1% | Emergency decompression if neurological deficit |
| Vasovagal reaction | 2-5% | Supportive care, fluids, observation |
| Transient neurological symptoms | 5-10% | Usually resolves within 24-48 hours |
Spinal Cord Stimulation
| Complication | Incidence | Management |
|---|---|---|
| Lead migration | 10-15% | Revision, lead repositioning |
| Infection | 2-5% | Antibiotics; explant if severe |
| Hardware failure | 5-10% | Battery replacement, lead revision |
| Loss of efficacy | 20-30% over time | Reprogramming, lead revision, explant |
| Pain at generator site | 5-10% | Repositioning, smaller device |
| Cerebrospinal fluid leak | Under 1% | Conservative management, blood patch |
Radiofrequency Ablation
| Complication | Incidence | Notes |
|---|---|---|
| Neuritis/dysesthesia | 5-10% | Usually temporary, resolves over weeks |
| Skin burns | Under 1% | Proper grounding technique prevents |
| Infection | Under 1% | Sterile technique essential |
| Weakness (motor nerve injury) | Under 1% | Careful localization prevents |
Complications of Revision Surgery
Intraoperative Complications
| Complication | Primary Surgery | Revision Surgery | Implications |
|---|---|---|---|
| Dural tear | 3-10% | 10-20% | Higher risk due to scarring, usually repairable |
| Neurological injury | 1-3% | 3-8% | More difficult dissection through scar tissue |
| Vascular injury | Under 1% | 1-3% | Altered anatomy increases risk |
| Wrong level | 1-3% | 1-2% | Careful imaging verification essential |
| Inadequate decompression | 5-10% | 10-15% | Scar tissue obscures anatomy |
Early Postoperative Complications (Under 6 Weeks)
| Complication | Incidence | Prevention/Management |
|---|---|---|
| Infection (superficial) | 2-5% | Prophylactic antibiotics, sterile technique |
| Infection (deep/discitis) | 1-3% | Emergency I&D, long-term IV antibiotics |
| Hematoma | 2-5% | Meticulous hemostasis, drain placement |
| Pseudomeningocele | 2-5% | Watertight dural closure, prone positioning |
| DVT/PE | 1-3% | Early mobilization, chemoprophylaxis |
| Urinary retention | 5-15% | Catheterization, alpha-blockers |
Late Complications (Over 6 Weeks)
| Complication | Incidence | Time Course |
|---|---|---|
| Pseudarthrosis | 15-30% (revision fusion) | 6-18 months |
| Hardware failure | 5-10% | Variable, months to years |
| Adjacent segment disease | 5-25% | 5-10 years post-fusion |
| Recurrent stenosis | 10-20% | Variable, months to years |
| Chronic pain (persistent FBSS) | 30-50% | Ongoing |
| Junctional kyphosis | 5-15% (long fusions) | Years |
Specific High-Risk Scenarios
Third or Subsequent Revision Surgery
- Complication rates exceed 40%
- Success rates under 30%
- Each revision increases scar tissue burden
- Neurological injury risk doubles with each procedure
- Consider non-surgical options preferentially
Revision in Setting of Active Litigation
- Outcomes significantly worse
- Psychological factors dominant
- Higher pain scores despite anatomical success
- Consider delaying surgery until litigation resolved
Revision with Concurrent Opioid Dependence
- Postoperative pain management extremely challenging
- Higher infection rates
- Delayed healing
- Require structured tapering program preoperatively
Exam Pearl
Complication rates INCREASE with each revision: First revision has 15-25% complication rate. Second revision 25-40%. Third or more over 40%. Always counsel patients about cumulative risk with multiple operations!
Prevention Strategies
Reducing Complications
| Strategy | Impact |
|---|---|
| Careful patient selection | Most important factor |
| Preoperative optimization | Smoking cessation, weight loss, diabetes control |
| Meticulous surgical technique | Minimize tissue trauma, adequate hemostasis |
| Antibiotic prophylaxis | Reduces infection risk |
| Early mobilization | Reduces VTE risk |
| Multidisciplinary approach | Addresses all contributing factors |
Evidence Base
PROCESS Trial: SCS vs Conventional Management
- Spinal cord stimulation superior to conventional medical management for FBSS with predominant leg pain
- At 6 months: 48% of SCS patients achieved primary outcome (50% leg pain relief) vs 9% of controls
- Crossover rate high in control group (32% crossed to SCS due to inadequate relief)
- Benefit sustained at 12 and 24 months follow-up
- Quality of life significantly improved in SCS group
- Complication rate acceptable with 5% requiring revision
Gadolinium Enhancement Patterns in Postoperative Spine
- Epidural scar enhances immediately (under 5 minutes post-gadolinium) with peripheral pattern
- Recurrent disc shows delayed (15-30 minutes) central enhancement or no enhancement
- MRI with gadolinium: 95% sensitivity and 77% specificity for scar vs disc distinction
- Timing of post-contrast imaging critical for accurate interpretation
- T1-weighted images most useful for enhancement assessment
- Mass effect present with recurrent disc, minimal with scar
Outcomes of Revision Lumbar Discectomy
- First revision discectomy for recurrent herniation: 65% good-excellent outcomes
- Second revision discectomy: success decreased to 35%
- Outcomes significantly better when recurrent herniation clearly identified on MRI
- Surgery for scar tissue alone had poor outcomes (under 40%)
- Dural tear rate 15% (higher than primary surgery 5-8%)
- Patient selection critical - favorable psychosocial profile improves outcomes
Psychosocial Predictors of Surgical Outcome
- Depression and passive coping strategies strongest predictors of poor surgical outcome
- Psychosocial factors MORE predictive than MRI findings
- Patients with high psychological distress: 3-fold higher risk of FBSS
- Catastrophizing behavior significantly associated with chronic pain
- Workers' compensation and litigation strongly predict poor outcomes
- Preoperative psychological screening recommended for all spine surgery candidates
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Burton CV, Kirkaldy-Willis WH, Yong-Hing K, Heithoff KB. Causes of failure of surgery on the lumbar spine. Clin Orthop Relat Res. 1981;(157):191-199.
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Slipman CW, Shin CH, Patel RK, et al. Etiologies of failed back surgery syndrome. Pain Med. 2002;3(3):200-214. doi:10.1046/j.1526-4637.2002.02033.x
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Flum AS, Hickey A, Flum DR. Understanding the psychological factors affecting failed back surgery syndrome: a systematic review. Healthcare (Basel). 2021;9(10):1275. doi:10.3390/healthcare9101275
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Thomson S, Jacques L. Demographic characteristics of patients with severe neuropathic pain secondary to failed back surgery syndrome. Pain Pract. 2009;9(3):206-215. doi:10.1111/j.1533-2500.2009.00276.x
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Kumar K, North R, Taylor R, et al. Spinal cord stimulation vs. conventional medical management: a prospective, randomized, controlled, multicenter study of patients with failed back surgery syndrome (PROCESS study). Neuromodulation. 2005;8(4):213-218. doi:10.1111/j.1525-1403.2005.00027.x
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Persistent Radiculopathy After Microdiscectomy
"A 45-year-old male underwent L5-S1 microdiscectomy 6 months ago for right L5 radiculopathy. He had 2 weeks of improvement but now has recurrent right leg pain worse than preoperatively. MRI shows soft tissue in the epidural space at L5-S1. How would you evaluate and manage this patient?"
Scenario 2: Wrong Level Surgery
"A 60-year-old female underwent L4-5 decompression for neurogenic claudication 3 months ago. She has had no improvement in symptoms. Review of her postoperative MRI shows decompression was performed at L3-4, not L4-5. The patient is now consulting you for a second opinion. How do you manage this situation?"
Scenario 3: Chronic FBSS with Multiple Previous Surgeries
"A 50-year-old male presents with chronic back and leg pain. He has had 3 previous lumbar surgeries: L5-S1 discectomy, then L4-5 decompression, then L4-S1 fusion. His pain never improved. He is on high-dose opioids and is requesting another operation. MRI shows solid fusion with no obvious structural pathology. How would you assess and manage this patient?"
MCQ Practice Points
Exam Pearl
Q: What are the most common causes of failed back surgery syndrome (FBSS)?
A: Recurrent or residual disc herniation (most common surgically treatable cause); Foraminal stenosis (especially lateral recess); Adjacent segment disease; Pseudarthrosis (failed fusion); Epidural fibrosis/scar tissue; Segmental instability; Wrong level surgery; Unrecognized spinal stenosis. Non-structural causes: Central sensitization, psychological factors, secondary gain, undiagnosed pain generator (SIJ, facet, hip).
Exam Pearl
Q: How do you evaluate a patient with persistent pain after lumbar spine surgery?
A: History: Pain timing (immediate vs delayed), character (radicular vs axial), response to previous surgery, red flags. Examination: Neurological assessment, provocative tests (SIJ, facet), hip examination. Imaging: MRI with gadolinium (differentiates scar from recurrent disc); CT for bony detail, fusion assessment; Standing X-rays for instability. Diagnostic injections: Selective nerve root blocks, facet blocks, SIJ injection, discography if indicated. Multidisciplinary pain assessment recommended.
Exam Pearl
Q: How do you differentiate epidural fibrosis from recurrent disc herniation on MRI?
A: Both can cause nerve compression post-discectomy. Recurrent disc herniation: Mass effect with peripheral enhancement on gadolinium (enhancing rim around non-enhancing disc material); Contiguous with disc space. Epidural fibrosis: Diffuse homogeneous enhancement throughout scar tissue; Retracts and conforms to dural sac rather than displacing it; May extend around nerve root. Clinical correlation essential - scar alone rarely causes significant symptoms.
Exam Pearl
Q: What is the role of spinal cord stimulation in FBSS?
A: Spinal cord stimulation (SCS) is evidence-based treatment for neuropathic leg pain in FBSS when conservative measures fail. Mechanism: Modulates pain transmission via dorsal column stimulation. Best results: Predominant radicular/neuropathic leg pain (greater than axial back pain); Failed conservative therapy; No surgically correctable pathology; Psychological screening passed. Trial stimulator first; Permanent implant if greater than 50% pain reduction. Less effective for predominantly axial back pain.
Exam Pearl
Q: What are the predictors of poor outcome after revision spine surgery for FBSS?
A: Poor prognostic factors: Multiple prior surgeries (success rate drops with each revision); Predominant axial back pain (vs radicular); Worker's compensation/litigation; Psychological comorbidities (depression, catastrophizing); Smoking; Chronic opioid use; Long duration of symptoms pre-revision; No clear anatomical pain generator identified. Patient selection is critical - multidisciplinary assessment recommended before revision surgery.
Australian Context
Multidisciplinary Pain Services: Australian pain management guidelines recommend referral to multidisciplinary pain services for chronic FBSS. Major tertiary hospitals have dedicated spinal pain clinics.
Spinal Cord Stimulation Access: SCS devices are available through the Prostheses List with private health insurance coverage. Public hospital access varies by state but is generally available at major spine centres.
PBS Medications: Gabapentinoids (pregabalin, gabapentin) and duloxetine are PBS-subsidised for neuropathic pain management. Opioid prescribing follows Australian TGA guidelines with real-time prescription monitoring.
WorkCover Considerations: Many FBSS patients have workers' compensation claims. Independent medical assessments and whole person impairment ratings guide compensation decisions under state-based legislation.
FAILED BACK SURGERY SYNDROME
High-Yield Exam Summary
Definition and Epidemiology
- •FBSS: Persistent or recurrent pain post-lumbar surgery despite anatomical success
- •Incidence: 10-40% depending on procedure (higher for fusion vs discectomy)
- •NOT a specific diagnosis - heterogeneous syndrome requiring systematic evaluation
- •Strongest predictors: Psychosocial factors (depression, catastrophizing)
Common Causes (Mnemonic: FAILED)
- •F - Fibrosis (epidural scar) - most common chronic cause
- •A - Adjacent segment disease (5-25% by 10 years post-fusion)
- •I - Inadequate decompression (residual stenosis, retained disc fragment)
- •L - Level wrong (5-15% incidence - never event)
- •E - Epidural hematoma or infection (early complications)
- •D - Disc recurrent herniation (5-15% following discectomy)
Diagnostic Imaging - MRI with Gadolinium
- •Scar: EARLY enhancement (under 5 min) with PERIPHERAL pattern
- •Recurrent disc: NO enhancement or DELAYED CENTRAL enhancement (over 15 min)
- •Mass effect: Minimal with scar, present with recurrent disc
- •Arachnoiditis: Clumped nerve roots, empty thecal sac sign
- •Dynamic X-rays: Instability if over 3-4mm translation or over 10-15 degrees angulation
Management Algorithm
- •First-line: Conservative (PT, neuropathic meds, CBT) - 40-60% improve
- •Interventional: Epidural injections (50-70% for radicular pain), RFA for facets
- •Neuromodulation: SCS for radicular pain - PROCESS trial shows 50% reduction
- •Surgery: ONLY if clear structural pathology (recurrent disc, stenosis, instability)
- •Success rates decrease: Primary 80%, 1st revision 60%, 2nd revision 40%, 3rd under 30%
Spinal Cord Stimulation
- •Indications: Radicular leg pain, failed 6mo conservative care, no surgical lesion
- •Trial mandatory: 5-7 days, success defined as over 50% pain reduction
- •Evidence: PROCESS trial - SCS superior to conventional management at 6mo
- •Outcomes: 50-70% achieve over 50% pain reduction long-term
- •Better for leg pain than back pain, best with favorable psych profile
Prevention Strategies (Mnemonic: PREVENT)
- •P - Psychosocial screening preoperatively
- •R - Right diagnosis (correlate symptoms with imaging)
- •E - Expectations managed (realistic goals discussion)
- •V - Verify level intraoperatively (AP and lateral imaging BEFORE incision)
- •E - Early mobilization (prevent deconditioning)
- •N - Nerve protection (minimize retraction, preserve blood supply)
- •T - Tissue preservation (limit dissection, preserve under 50% facets)
High-Yield Exam Points
- •FBSS vs surgical failure: FBSS = anatomically successful, failure = technical error
- •Gadolinium timing CRITICAL: Early peripheral (scar) vs delayed or none (disc)
- •Psychosocial factors predict outcomes MORE than surgical technique
- •Multidisciplinary pain programs: Best long-term functional outcomes
- •Avoid next operation syndrome: Each surgery lower success, higher risk
- •SCS evidence-based (PROCESS trial) for radicular pain post-surgery