Spinal osteotomies enable powerful deformity correction with increasing complexity and risk. SPO (Smith-Petersen osteotomy) is a posterior column only procedure providing 10 degrees per level through a posterior-opening wedge with intact anterior column as hinge. PSO (pedicle subtraction osteotomy) resects all three columns via posterior approach, achieving 30-40 degrees correction at a single level with 10-15mm shortening. VCR (vertebral column resection) removes the entire vertebra allowing 50-70 degrees correction but carries highest risk. Neurological complication rates increase with complexity: SPO 1-3%, PSO 5-11%, VCR 10-25%. Match osteotomy type to deformity magnitude - neuromonitoring is mandatory.

Three-Column Concept of the Spine

Denis Three-Column Model:

1. Anterior Column:

   • Anterior longitudinal ligament
   • Anterior half of vertebral body
   • Anterior half of disc

2. Middle Column:

   • Posterior half of vertebral body
   • Posterior half of disc
   • Posterior longitudinal ligament

3. Posterior Column:

   • Pedicles, laminae, facets
   • Ligamentum flavum
   • Interspinous and supraspinous ligaments

Osteotomy Classification by Columns Affected:

• SPO: Posterior column only (Grade 1-2 osteotomy)
• PSO: All three columns (Grade 3 osteotomy)
• VCR: All three columns with complete vertebral resection (Grade 4-6 osteotomy)

Biomechanical Principles

Axis of Rotation:

• SPO: Axis anterior to anterior longitudinal ligament

  • Opens posteriorly, closes anteriorly
  • Requires intact anterior column to act as hinge
  • Limited correction potential per level

• PSO: Axis through middle of vertebral body

  • Symmetrical closure
  • No anterior column hinge required
  • Greater correction potential per level

• VCR: Axis at surgeon's choice (depends on rod position)

  • Maximum flexibility in correction plane
  • Can address both sagittal and coronal deformity simultaneously
  • Requires temporary instability during closure

Correction Potential:

• SPO: 10 degrees per level (range 5-15 degrees)
• PSO: 30-40 degrees per level (range 25-45 degrees)
• VCR: 50-70 degrees per level (range 40-80 degrees)

Spinal Shortening:

• SPO: Minimal shortening (anterior column intact)
• PSO: 10-15mm shortening at osteotomy level
• VCR: 20-40mm shortening (entire vertebra removed)
• Shortening relaxes neural elements but may affect visceral structures

Anatomical Considerations

Vascular Anatomy:

• Lumbar Segmental Arteries: Exit at mid-vertebral body

  • At risk during PSO (vertebral body resection)
  • Sacrifice usually tolerated due to collaterals
  • Excessive bleeding risk in vascular disease

• Artery of Adamkiewicz:

  • Typically T9-L2 on left (75% of cases)
  • Major anterior spinal artery supply
  • Injury causes paraplegia (anterior cord syndrome)
  • Risk minimized by maintaining MAP greater than 85 mmHg

Neural Anatomy:

• Conus Medullaris: Typically T12-L2

  • Higher risk of myelopathy if osteotomy at this level
  • Lumbar levels (L3-L4) preferred for PSO

• Cauda Equina: Below L2

  • More tolerant of manipulation than spinal cord
  • Individual nerve roots can be mobilized

• Exiting vs Traversing Roots:

  • Exiting root in neural foramen (vulnerable to pedicle work)
  • Traversing root medial to pedicle (vulnerable to canal work)

Schwab Classification of Spinal Osteotomies

Anatomic Location Classification

Cervical Osteotomies:

• Highest neurological risk (spinal cord injury = quadriplegia)
• Typically SPO or opening wedge osteotomy
• PSO/VCR rarely performed (extreme risk)

Thoracic Osteotomies:

• T1-T10: Spinal cord present, myelopathy risk
• Narrow canal, less room for error
• PSO preferred over VCR when possible

Thoracolumbar Osteotomies:

• T11-L2: Conus medullaris level (high risk)
• Avoid if possible, prefer L3-L4 for PSO

Lumbar Osteotomies:

• L3-L4: Preferred level for PSO (below conus, cauda equina tolerates manipulation)
• L5: Avoid PSO (proximity to sacrum, large vessels)

Sacral Osteotomies:

• Rare, typically for pelvic incidence reduction
• S1 or S2 level
• Risk of bowel/bladder dysfunction

Deformity-Based Classification

Sagittal Plane Deformities:

• Flatback: PSO for lordosis restoration
• Kyphosis: PSO or VCR depending on magnitude and rigidity
• Chin-on-chest: Multiple SPOs or cervicothoracic VCR

Coronal Plane Deformities:

• Scoliosis: Asymmetric VCR for coronal and rotational correction
• Coronal Imbalance: VCR at apex with lateral translation

Combined Deformities:

• Kyphoscoliosis: VCR for simultaneous sagittal and coronal correction
• 3D Deformity: Multiple osteotomies or extended VCR

Patient Selection for Osteotomy

Ideal Candidate for PSO:

• Fixed sagittal imbalance (SVA greater than 50mm, PI-LL mismatch greater than 20 degrees)
• Failed conservative management (minimum 6 months)
• Rigid deformity not correctable with positioning
• Good bone quality (T-score greater than -2.0)
• Age less than 70 years
• Medical fitness for major surgery
• Realistic expectations

Contraindications to Osteotomy:

Absolute:

• Active infection at osteotomy site
• Severe osteoporosis (T-score less than -3.5) without treatment
• Prohibitive medical comorbidities (severe cardiac, pulmonary disease)
• Unrealistic expectations or psychiatric contraindications

Relative:

• Age greater than 75 years
• Moderate osteoporosis (T-score -2.5 to -3.0)
• Prior radiation to osteotomy site
• Severe obesity (BMI greater than 40)
• Revision at same level

Deformity Assessment

Radiographic Assessment:

• Standing Full-Length Spine: AP and lateral
• Sagittal Parameters:
  • SVA: Normal less than 50mm
  • PI-LL mismatch: Normal within 10 degrees
  • Pelvic tilt: Compensation mechanism (normal less than 20 degrees)
  • Thoracic kyphosis: Normal 20-50 degrees

Deformity Magnitude:

• Mild: SVA 50-75mm, PI-LL 10-20 degrees → Multiple SPOs
• Moderate: SVA 75-150mm, PI-LL 20-40 degrees → Single PSO
• Severe: SVA greater than 150mm, PI-LL greater than 40 degrees → PSO + SPOs or VCR

Flexibility Assessment:

• Supine Hyperextension Film: Assesses deformity flexibility
• Traction Films: Pull test for deformity reducibility
• Rigid Deformity: Less than 10 degree correction on flexibility films → PSO or VCR
• Flexible Deformity: Greater than 20 degree correction → SPOs may suffice

Preoperative Evaluation

Medical Clearance:

• Cardiac evaluation (ECG, echo if indicated, stress test if CAD risk)
• Pulmonary function tests if restrictive lung disease
• Renal function (creatinine clearance for contrast studies, blood loss)
• Coagulation studies and type/screen (anticipate 2-4 unit PRBC transfusion)

Neurological Baseline:

• Document complete neurological examination
• MRI to assess spinal cord (myelomalacia, stenosis, tumor)
• Consider urodynamics if bowel/bladder symptoms

Bone Quality:

• DEXA scan mandatory
• Optimize if osteoporotic (vitamin D, calcium, teriparatide)
• Consider cement augmentation if T-score less than -2.5

📊 Management Algorithm

Click to expand

Osteotomy Selection Algorithm:

1. Assess Deformity Magnitude:

   • SVA less than 100mm with flexible deformity: Multiple SPOs
   • SVA 100-150mm with rigid deformity: Single PSO at L3
   • SVA greater than 150mm or severe angular deformity: PSO + SPOs or VCR

2. Evaluate Rigidity:

   • Greater than 20 degrees correction on flexibility films: SPOs may suffice
   • Less than 10 degrees correction: Requires bony osteotomy (PSO or VCR)

3. Match Correction to Deformity:

   • SPO: 10 degrees per level (posterior column only)
   • PSO: 30-40 degrees per level (all three columns)
   • VCR: 50-70 degrees per level (complete vertebrectomy)

Smith-Petersen Osteotomy (SPO)

Indications:

• Flexible kyphosis requiring 10-30 degrees total correction
• Ankylosing spondylitis with mild-moderate deformity
• Scheuermann's kyphosis
• Post-laminectomy kyphosis (iatrogenic flatback)

Technique:

Step 1 - Exposure:

• Midline incision over planned osteotomy levels
• Subperiosteal dissection exposing laminae and facets
• Identify levels with radiograph (count from C7 or sacrum)

Step 2 - Posterior Element Resection:

• Remove inferior facet completely (leave superior facet intact)
• Remove ligamentum flavum
• Resect spinous process and interspinous ligament
• Thin superior lamina to create hinge point
• Wide resection creates V-shaped gap

Step 3 - Instrumentation:

• Place pedicle screws 2-3 levels above and below each osteotomy
• Temporary rods to maintain stability during multiple osteotomies

Step 4 - Closure:

• Gradual compression on rods closes posterior gap
• Anterior column acts as hinge (must be intact)
• Monitor neuromonitoring during closure
• Achieve desired lordosis restoration

Step 5 - Final Fixation:

• Permanent rod placement
• Cross-links for rotational stability
• Bone graft over osteotomy sites

Pearls:

• Multiple levels better than single level (distributes stress)
• Apex of kyphosis is optimal location
• Preserve anterior column (DO NOT violate anterior longitudinal ligament)
• Gradual closure reduces neurological risk

Pitfalls:

• Fracture through anterior column (loss of hinge, unstable)
• Excessive correction at single level (neurological injury)
• Inadequate facet resection (limited correction, rod stress)

Pedicle Subtraction Osteotomy (PSO)

Indications:

• Fixed sagittal imbalance requiring 30-40 degrees correction
• Flatback deformity with PI-LL mismatch greater than 20 degrees
• Rigid kyphosis not amenable to SPO
• Revision deformity surgery

Optimal Level Selection:

• L3: Most common (below conus, good bone stock, central lordosis)
• L2: Acceptable if L3 anatomy unfavorable
• L4: Avoid if possible (proximity to L5-S1, lordosis distribution)
• Thoracic: High risk (spinal cord), avoid if possible

Technique:

Step 1 - Exposure and Instrumentation:

• Wide midline exposure from 3-4 levels above to 3-4 levels below
• Place all pedicle screws first (including osteotomy level)
• Temporary rods for stability
• Identify osteotomy level with fluoroscopy

Step 2 - Posterior Element Resection:

• Complete laminectomy at osteotomy level (L3)
• Bilateral facetectomy (L2-L3 and L3-L4)
• Resect spinous processes L2, L3, L4
• Expose pedicles completely (circumferential)
• Identify and protect nerve roots (exiting L3 root at risk)

Step 3 - Pedicle Resection:

• Remove pedicles with osteotomes or high-speed burr
• Start lateral, work medial to avoid nerve injury
• Create cortical shell of posterior vertebral body
• Expose lateral walls of vertebral body

Step 4 - Vertebral Body Resection:

• Use curettes, osteotomes, or high-speed burr
• Create wedge-shaped defect (wider posteriorly)
• Preserve anterior cortex (1-2mm shell)
• Angle: 30-40 degrees from horizontal
• Copious irrigation to prevent thermal injury

Step 5 - Temporary Stabilization:

• Place temporary rods with moderate compression
• Prevents premature closure during contralateral work
• Maintain canal decompression

Step 6 - Closure:

• Gradually compress bilateral rods
• Posterior wedge closes, anterior cortex fractures (controlled hinge)
• Monitor neuromonitoring (SSEP, MEP) continuously
• Stop if significant neuromonitoring changes
• Shortening of 10-15mm relaxes neural elements

Step 7 - Final Fixation:

• Permanent rod placement (cobalt-chromium 6.0-6.35mm)
• Dual rods for high-stress cases
• Multiple cross-links (every 3-4 levels)
• Bone graft entire construct

Intraoperative Pearls:

• Four-Rod Technique: Temporary rods during osteotomy, permanent rods after closure
• Cell Saver: Autotransfusion reduces allogeneic blood transfusion
• Hypotensive Anesthesia: Reduce blood loss (maintain MAP 65-70 during resection)
• Maintain MAP greater than 85 during closure: Spinal cord perfusion
• Have wake-up test ready: If neuromonitoring changes persist

Complications During PSO:

• Excessive Bleeding: Segmental arteries, epidural plexus
  • Management: Hemostatic agents, temporary closure, blood transfusion
• Neurological Injury: Traction on nerve roots, cord ischemia
  • Management: Release compression, augment blood pressure, consider wake-up test
• Anterior Cortex Fracture Too Early: Uncontrolled closure
  • Management: Temporary stabilization, controlled gradual closure
• Inadequate Correction: Insufficient bone resection
  • Management: Remove more bone (carefully), accept and add SPO at adjacent level

Vertebral Column Resection (VCR)

Indications:

• Severe rigid deformity requiring greater than 50 degrees correction
• Sharp angular kyphosis (kyphoscoliosis)
• Congenital deformity (hemivertebra, bar)
• Tumor resection with reconstruction
• Failed PSO requiring salvage

Level Selection:

• Apex of deformity (maximum correction with single level)
• Avoid conus medullaris (T12-L2) if possible
• Thoracic VCR requires ICU monitoring (cord injury = paraplegia)

Technique:

Step 1 - Extensive Exposure:

• Wide exposure 5-6 levels above and below
• Circumferential exposure of vertebra to be resected
• Place all pedicle screws excluding VCR level

Step 2 - Posterior Element Removal:

• Complete laminectomy at VCR level and adjacent levels
• Bilateral facetectomies above and below
• Identify and protect nerve roots (dura completely exposed)

Step 3 - Pedicle and Posterior VB Resection:

• Resect pedicles bilaterally with burr or osteotome
• Remove posterior wall of vertebral body
• Create working channel to anterior column

Step 4 - Lateral and Anterior VB Resection:

• Blunt dissection laterally (protect great vessels)
• Ligate segmental arteries if necessary
• Resect vertebral body completely (anterior cortex last)
• Elevate disc above and below (remove completely)

Step 5 - Temporary Stabilization:

• Place temporary rods to prevent catastrophic collapse
• Dura completely exposed (360 degree decompression)
• Sac of neural elements free-floating

Step 6 - Gradual Closure and Correction:

• Slowly compress rods to close gap
• Monitor neuromonitoring continuously
• Translate spine as needed for coronal correction
• Rotate spine for rotational correction
• Shortening of 20-40mm

Step 7 - Anterior Column Reconstruction:

• Place structural graft (cage, mesh, allograft bone)
• Provides anterior column support
• Allows bone ingrowth for fusion
• Prevents kyphosis recurrence

Step 8 - Final Fixation:

• Robust fixation with dual rods (four-rod construct)
• Cobalt-chromium 6.35mm diameter
• Multiple cross-links for stability
• Extend fixation 4-5 levels beyond VCR

Anterior vs Posterior-Only VCR:

Posterior-Only (Single-Stage):

• Advantages: Single surgery, less morbidity, shorter recovery
• Disadvantages: Limited anterior access, higher blood loss, more technically demanding
• Preferred for most cases if surgeon experienced

Staged Anterior-Posterior:

• Advantages: Better anterior column visualization, controlled resection
• Disadvantages: Two surgeries, increased morbidity, longer hospitalization
• Indicated for: Tumor resection, extensive anterior pathology, vascular anomalies

Complications of VCR:

• Neurological Injury (10-25%): Highest of all osteotomies
  • Prevention: Meticulous technique, neuromonitoring, gradual closure
• Vascular Injury: Great vessels, segmental arteries
  • Prevention: Blunt dissection, vascular surgery standby for thoracic VCR
• Massive Blood Loss: Average 2-5 liters
  • Prevention: Cell saver, controlled hypotension, hemostatic agents
• Construct Failure: Rod fracture, screw pullout
  • Prevention: Robust fixation (dual rods, extend fixation)

Immediate Postoperative Care (ICU - First 24-48 Hours)

Neurological Monitoring:

• Frequent Neuro Checks: Every 1-2 hours for first 24 hours
• Document: Motor strength (all myotomes), sensation, reflexes
• Wake Patient Early: Assess for deficits as soon as safely extubated
• Urgent MRI if Deficit: Rule out hematoma, hardware malposition

Hemodynamic Management:

• Maintain MAP greater than 85 mmHg: Spinal cord perfusion (first 48 hours)
• Vasopressors if Needed: Phenylephrine or norepinephrine
• Fluid Resuscitation: Replace blood loss (target Hb greater than 8 g/dL)
• Monitor Urine Output: Target greater than 0.5 mL/kg/hour

Pain Management:

• Multimodal Analgesia: Acetaminophen, NSAIDs (if renal function allows), gabapentin
• Epidural: Excellent pain control if placed preoperatively
• PCA (Patient-Controlled Analgesia): Opioids as needed
• Avoid Excessive Opioids: Delirium, ileus, respiratory depression

Drain Management:

• Closed Suction Drains: Monitor output (expect 200-400 mL first 24 hours)
• Remove When Output less than 50 mL per 8 hours: Typically POD 2-3
• Watch for Excessive Bleeding: Greater than 500 mL in 8 hours → consider re-exploration

Early Mobilization (POD 1-5)

Out of Bed:

• POD 1: Sit at edge of bed if neurologically intact
• POD 2: Sit in chair, stand with assistance
• POD 3: Walk with walker or assistance
• Goal: Walking independently by discharge

Bracing:

• TLSO Brace: For PSO/VCR patients, worn for 12 weeks
• No Brace if SPO Only: Unless multiple levels or poor bone quality
• Custom-Molded: Better fit, compliance

Physical Therapy:

• Early Mobilization: Reduces DVT, pneumonia, ileus
• Core Strengthening: Gentle isometrics (no trunk rotation for 12 weeks)
• Gait Training: Restore normal gait pattern
• ADL Training: Transfers, stairs, dressing

Complications and Management

Neurological Deficit:

Immediate Postoperative Deficit:

• Urgency: Emergent evaluation
• Differential: Epidural hematoma (most common), hardware malposition, cord ischemia
• Workup: Urgent MRI, check coagulation studies
• Management:
  • Hematoma: Emergent evacuation (decompress within 8 hours for best recovery)
  • Hardware malposition: Revision to remove offending screw/rod
  • Cord ischemia: Augment MAP to 90-100 mmHg, steroids controversial (no proven benefit)

Delayed Deficit (POD 1-7):

• Causes: Delayed hematoma, overcorrection with stretch injury, cord ischemia
• Management: Similar to immediate deficit, MRI to differentiate

Neurological Recovery:

• Incomplete Deficits: 50-70% significant recovery
• Complete Deficits: Poor prognosis (less than 20% recovery)
• Nerve Root Injuries: Better prognosis than cord injuries

Wound Complications:

• Hematoma/Seroma: Aspiration vs surgical drainage
• Superficial Infection: Antibiotics, local wound care
• Deep Infection: Irrigation and debridement, retain hardware if early (less than 3 months)

Medical Complications:

• DVT/PE: Mechanical prophylaxis POD 0, chemical POD 1 (after drain removal)
• Ileus: Early mobilization, minimize opioids, NG tube if severe
• Pneumonia: Incentive spirometry, early mobilization, respiratory therapy
• Delirium: Especially age greater than 65, minimize opioids and benzos, reorient

Surveillance and Follow-Up

Early Follow-Up (First 3 Months):

• 2 Weeks: Wound check, staple removal, neurological exam
• 6 Weeks: Radiographs (AP/Lateral standing), advance PT, pain assessment
• 12 Weeks: Radiographs, discontinue brace if appropriate, functional assessment

Late Follow-Up (3 Months to 2 Years):

• 6 Months: Radiographs, CT if fusion concern, return to light activities
• 12 Months: Radiographs and CT to confirm fusion, return to full activities
• 24 Months: Final radiographs, assess for adjacent segment degeneration

Radiographic Assessment:

• Immediate Postop: Confirm correction achieved, hardware position
• 6 Weeks: Assess for early hardware failure (screw loosening, rod fracture)
• 12 Weeks: Look for loss of correction
• 12 Months: CT to confirm fusion (greater than 50% bridging bone)

Functional Outcome Measures:

• ODI (Oswestry Disability Index): Baseline, 6 months, 12 months
• SRS-22: Spine-specific quality of life
• VAS Pain Score: Track pain improvement
• Walking Distance: Objective functional measure

Neurological Complications

Risk Factors for Neurological Injury:

• Revision osteotomy at same level (epidural scarring)
• Thoracic location (spinal cord present)
• Excessive correction (greater than 40 degrees PSO, greater than 60 degrees VCR)
• Osteoporosis (vertebral body fracture during closure)
• Vascular disease (cord ischemia)

Neuromonitoring:

• SSEPs (Somatosensory Evoked Potentials): Monitor dorsal column
  • Alert: Greater than 50% amplitude decrease or greater than 10% latency increase
  • Sensitivity: 75-85% for sensory deficits
• MEPs (Motor Evoked Potentials): Monitor corticospinal tract
  • Alert: Greater than 50% amplitude decrease
  • Sensitivity: 85-95% for motor deficits (more reliable than SSEPs)
• Triggered EMG: Pedicle screw placement, nerve root monitoring
• Continuous Free-Running EMG: Nerve root irritation during dissection

Response to Neuromonitoring Changes:

1. Notify surgeon immediately
2. Augment blood pressure (MAP to 90-100 mmHg)
3. Release recent manipulation (stop compression, reduce correction)
4. Reassess signals (wait 10-15 minutes)
5. Wake-up test if signals do not return
6. Accept less correction if needed (neurological preservation paramount)

Vascular Complications

Major Vascular Injury (Rare, Less than 1%):

• Great Vessels: Aorta, IVC (during anterior VCR exposure)
• Iliac Vessels: L4-L5 PSO or VCR
• Segmental Arteries: Ligated during PSO/VCR (usually tolerated)

Prevention:

• Blunt dissection laterally (protect vessels)
• Vascular surgery standby for high-risk cases
• Avoid anterior cortex violation until final closure

Management:

• Immediate vascular surgery consultation
• Direct pressure, hemostatic agents
• Repair or graft if major vessel injured
• Massive transfusion protocol

Artery of Adamkiewicz Injury:

• Anterior spinal artery thrombosis → paraplegia
• Prevention: Maintain MAP greater than 85, avoid excessive hypotension
• No effective treatment once injury occurs (devastating complication)

Mechanical Complications

Rod Fracture:

• Incidence: 5-10% at 2 years (higher with PSO/VCR)
• Risk Factors: Single rods, small diameter (5.5mm), pseudarthrosis
• Prevention: Dual rods, 6.35mm diameter, achieve solid fusion
• Management: Revision if symptomatic or pseudarthrosis present

Screw Loosening/Pullout:

• Incidence: 3-5% (higher in osteoporosis)
• Risk Factors: Osteoporosis, inadequate screw purchase, excessive stress
• Prevention: Cement augmentation if T-score less than -2.5, bicortical screws
• Management: Revision with longer/larger screws or cement augmentation

Proximal Junctional Kyphosis (PJK):

• Incidence: 20-40% after PSO/VCR
• Risk Factors: Osteoporosis, overcorrection, UIV at inflection point
• Prevention: Prophylactic vertebroplasty at UIV, gradual lordosis transition
• Management: Observation if asymptomatic, revision if symptomatic/severe

Pseudarthrosis:

• Incidence: 10-20% at 2 years
• Risk Factors: Smoking, diabetes, osteoporosis, inadequate biologics
• Prevention: Smoking cessation, autograft + BMP, teriparatide
• Management: Revision if symptomatic or hardware failure

Expected Outcomes by Osteotomy Type

Smith-Petersen Osteotomy:

• Correction Achieved: 90-95% achieve planned correction (10 degrees per level)
• Pain Relief: 70-80% significant improvement
• Fusion Rate: 90-95% (low-stress osteotomy)
• Complication Rate: 15-25% (mostly minor)
• Patient Satisfaction: 75-85%

Pedicle Subtraction Osteotomy:

• Correction Achieved: 80-90% achieve planned correction (30-40 degrees)
• Sagittal Balance: SVA less than 50mm achieved in 85-90%
• Pain Relief: 65-75% significant improvement
• Functional Improvement: 60-70% meaningful ODI improvement
• Fusion Rate: 85-90%
• Complication Rate: 40-50% (major complications 10-15%)
• Patient Satisfaction: 65-75%

Vertebral Column Resection:

• Correction Achieved: 75-85% achieve planned correction (50-70 degrees)
• Pain Relief: 60-70% significant improvement
• Functional Improvement: 55-65% meaningful improvement
• Fusion Rate: 75-85%
• Complication Rate: 50-70% (major complications 20-30%)
• Patient Satisfaction: 55-65%

Predictors of Success

Positive Predictors:

• Appropriate osteotomy selection (match to deformity)
• Achievement of solid fusion
• Restoration of sagittal balance (SVA less than 50mm, PI-LL within 10 degrees)
• Good bone quality (T-score greater than -2.0)
• Age less than 65 years
• Non-smoker
• Single osteotomy (vs multiple or revision)
• Realistic expectations

Negative Predictors:

• Severe osteoporosis (T-score less than -3.0)
• Active smoking
• Multiple comorbidities (Charlson index greater than 3)
• Revision osteotomy at same level
• Chronic opioid use preoperatively
• Poor nutritional status (albumin less than 3.5)
• Unrealistic expectations (expect complete cure)

Long-Term Outcomes

5-Year Outcomes:

• Maintained Correction: 75-85% maintain SVA less than 50mm
• Fusion Rate: 85-95% if solid at 1 year
• Adjacent Segment Disease: 20-30% develop symptomatic ASD
• Reoperation Rate: 15-25%
  • PJK (most common reason): 8-12%
  • Pseudarthrosis: 3-5%
  • Rod fracture: 3-5%
  • Infection: 2-3%

10-Year Outcomes:

• Limited data due to recent adoption of techniques
• Cumulative reoperation rate: 25-35%
• Patient satisfaction maintained: 60-70% of those initially satisfied
• Adjacent segment degeneration: cumulative 35-45%

Australian Epidemiology and Management

Complex Spine Surgery in Australia:

• Spinal osteotomy procedures concentrated at major tertiary centres (Royal North Shore, St Vincent's Melbourne, Royal Adelaide, Princess Alexandra Brisbane, Royal Perth)
• Fellowship-trained complex spine surgeons perform majority of PSO/VCR procedures
• Australian Spine Society (AOSS) maintains registry for deformity surgery outcomes
• Multidisciplinary spine deformity clinics at major centres coordinate complex cases

RACS Orthopaedic Training Relevance:

• Spinal osteotomies are high-yield FRACS Orthopaedic examination topics
• Key exam focus: Schwab classification, osteotomy selection based on deformity, neuromonitoring principles
• Viva scenarios commonly test response to neuromonitoring changes and patient selection
• Understanding of biomechanical principles (correction potential, axis of rotation) is examined

Private Health Insurance:

• Complex spine surgery requires prosthesis billing (rods, screws, cages)
• Prostheses List items covered under hospital insurance
• Extended ICU and hospital stay typical for PSO/VCR (7-14 days)

AHPRA and TGA Considerations:

• Spinal implants (pedicle screws, rods, cages) require TGA registration
• BMP (bone morphogenetic protein) usage for fusion augmentation is off-label in spine
• Informed consent must address specific TGA-registered implant details

Training Pathway:

• AOSS Complex Spine Surgery Fellowship (1-2 years post-FRACS)
• International fellowship options (USA scoliosis centres, AOSpine fellowship)
• Minimum 50 PSO cases before independent practice recommended

Neuromonitoring Services:

• Dedicated intraoperative neurophysiology technicians required
• Available at all major Australian centres performing complex osteotomies
• SSEP and MEP monitoring standard of care for PSO/VCR

• Adult Deformity Surgery: Primary indication for osteotomies
• Revision Deformity Surgery: Often requires PSO or VCR for correction
• Proximal Junctional Kyphosis: Common complication after osteotomy
• Spinal Cord Monitoring: Essential for safe osteotomy execution
• Flatback Deformity: Most common indication for PSO
• Ankylosing Spondylitis: Classic indication for SPO
• Sagittal Balance: Understanding parameters guides osteotomy selection
• Rod Fractures: Mechanical complication after osteotomy