import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Immediately anterior to lamina (0-2mm gap), cervical cord diameter 10mm **Protection**: Thin lamina with burr before using Kerrison, use footplate attachments, stay in epidural space, avoid direct anterior pressure **Location**: Runs in foramen transversarium, 1.5-2mm lateral to lateral mass edge, anterior to C7 transverse process **Protection**: Stay medial during lateral mass exposure, Magerl trajectory 25° lateral (not >30°), palpate all 4 walls before screw insertion, avoid lateral dissection beyond facet edge **Location**: Exits above C5 pedicle (C4-5 foramen), shortest and most horizontal cervical root, 3-5mm from medial pedicle wall **Protection**: Magerl technique 45° cephalad (not >50°), medial screw breach >4mm requires revision, foraminal decompression <50% facet resection, gentle nerve hook palpation **Location**: Valveless Batson's plexus directly anterior to lamina (2-5mm from dura), engorges with increased abdominal pressure **Protection**: Reverse Trendelenburg 15-20° positioning, thrombin-soaked gelfoam, bipolar cautery (not monopolar), TXA consideration, meticulous hemostasis before closure **Location**: 0-2mm anterior to ligamentum flavum (3-5mm thick yellow structure), adherent in OPLL cases **Protection**: Thin lamina to eggshell before rongeur removal, identify ligamentum flavum (yellow), leave ossified dura intact in OPLL, repair tears primarily with 4-0 Nurolon ## Primary Indications **Absolute Indications**: - Multilevel cervical myelopathy (≥3 levels) with progressive neurological deficit - Cervical stenosis with PRESERVED cervical lordosis (20-40° C2-C7 Cobb angle) - OPLL (ossification of posterior longitudinal ligament) causing cord compression - Congenital cervical stenosis (canal diameter <13mm) with symptomatic myelopathy **Relative Indications**: - Failed conservative management of multilevel stenosis (>3-6 months) - Multilevel spondylotic myelopathy with posterior predominant compression - Multilevel cervical radiculopathy not amenable to anterior approach - Combined central and foraminal stenosis across multiple levels ## Contraindications **Absolute Contraindications**: - Cervical KYPHOSIS (requires anterior column support first or combined approach) - Primarily anterior pathology (large disc herniation, anterior osteophytes) - ACDF better - Active cervical spine infection (pyogenic discitis, osteomyelitis) - Medical instability precluding prolonged anesthesia **Relative Contraindications**: - Severe osteoporosis (T-score <-3.0) - screw purchase concerns - Previous posterior cervical surgery with scarring - Obesity with poor posterior neck anatomy exposure - Single or two-level disease (ACDF preferred for limited disease) - Loss of cervical lordosis <10° (consider combined approach) ## Clinical Assessment **Myelopathy Signs** (Upper Motor Neuron): - Hoffman's sign - flick distal phalanx middle finger causes thumb flexion - Inverted radial reflex - brachioradialis tap causes finger flexion (C5-6 lesion) - Hyperreflexia in lower extremities with clonus - Lhermitte's sign - neck flexion causes electric shock down spine - Gait disturbance - spastic gait, broad-based, circumduction **Radiculopathy Signs** (Lower Motor Neuron): - C5 - deltoid/biceps weakness, reduced biceps reflex - C6 - wrist extension weakness, reduced brachioradialis reflex - C7 - triceps weakness, reduced triceps reflex - C8 - finger flexion weakness, grip strength reduced **Modified JOA Score** (17 points): - Motor function upper extremity (0-5) - Motor function lower extremity (0-7) - Sensory upper extremity (0-2) - Sensory trunk and lower extremity (0-2) - Bladder function (0-1) - Score <12 indicates moderate-severe myelopathy requiring surgery ## Cervical Spine Functional Anatomy **Osseous Structures**: - C2-C7 vertebrae with lateral masses unique to cervical spine - Lateral mass bounded by superior and inferior articular processes - Foramen transversarium in C2-C6 transmits vertebral artery - C7 has largest spinous process (vertebra prominens), no VA in foramen - Uncovertebral joints (Luschka) posterolateral to vertebral body **Spinal Canal Dimensions**: - Normal cervical canal diameter: 14-18mm (sagittal) - Stenosis defined as <13mm absolute or <0.8 Pavlov ratio - Spinal cord diameter approximately 10mm - Safe zone for decompression: achieve >13mm canal diameter - Space available for cord (SAC) = canal diameter minus cord diameter **Lateral Mass Anatomy**: - Dimensions: 10-15mm height, 8-12mm width, 6-10mm AP depth - Safe screw trajectory avoids: medial (nerve root), lateral (VA), anterior (carotid) - Magerl safe zone: 25° lateral (range 15-30°), 45° cephalad (range 30-50°) - Anderson safe zone: 10° lateral (range 0-15°), 30° cephalad (range 20-40°) - Vertebral artery lies 1.5-2mm lateral to lateral mass edge at all levels **Nerve Root Anatomy**: - Cervical roots exit ABOVE correspondingly numbered vertebra - C5 root exits C4-5 foramen (unlike lumbar where L5 exits L5-S1) - Eight cervical roots but seven vertebrae (C8 root exits C7-T1) - C5 root is shortest (25-30mm) and most horizontal (90° from cord) - Root diameter: C5 4-5mm, C6-C7 3-4mm, C8 2-3mm **Vascular Anatomy**: - Vertebral artery enters foramen transversarium at C6 in 90% (C5 in 5%, C7 in 5%) - VA courses superiorly through C6-C2, then turns medially at C1-2 - Vertebral artery diameter 3-5mm (dominant side larger) - Anomalous VA course in 5-10% - tortuous or medially displaced - Anterior spinal artery (single) and paired posterior spinal arteries supply cord **Ligamentous Structures**: - Posterior longitudinal ligament (PLL) - anterior to cord, ossifies in OPLL - Ligamentum flavum - thick yellow elastic tissue (3-5mm), hypertrophies in stenosis - Interspinous ligaments and supraspinous ligament - posterior tension band - Facet capsules - important for stability, preserve >50% - Nuchal ligament - midline avascular raphe between trapezius muscles ## Biomechanics of Decompression and Fusion **Cervical Lordosis Requirements**: - Normal cervical lordosis: 20-40° C2-C7 Cobb angle - Lordosis necessary for spinal cord to occupy anterior canal (away from lamina) - Laminectomy removes posterior tension band → kyphotic tendency - Kyphosis causes anterior cord compression (cord draped over vertebral bodies) - Fusion restores/maintains lordosis → prevents swan-neck deformity **Post-Laminectomy Kyphosis**: - Incidence without fusion: 10-20% adults, 50% children - Incidence with fusion: <2% - Risk factors: multilevel laminectomy (>3 levels), young age (<25 years), pre-existing loss of lordosis - Prophylaxis: instrumented fusion, maintain/restore lordosis intraoperatively **Lateral Mass Screw Biomechanics**: - Pullout strength: 400-800N depending on bone density and trajectory - Optimal length: 12-14mm (unicortical), 16-18mm if bicortical attempted - Triangulation with bilateral screws provides coronal stability - Rod-screw construct provides immediate rigid fixation - Compression across levels loads posterolateral bone graft ## Imaging Assessment **MRI Cervical Spine** (Essential): - T2 sagittal: assess cord signal (hyperintensity indicates myelomalacia) - T2 axial: measure canal diameter, identify cord compression - T1 post-contrast: rule out tumor, infection, vascular malformation - Measure posterior cord shift anticipated after decompression - Identify OPLL (low signal on T2, ossified dura adherent to PLL) **CT Cervical Spine**: - Assess lateral mass dimensions for screw planning (especially C3 smallest) - Identify vertebral artery anomalies (tortuous course, medial displacement) - Evaluate bone quality (osteoporosis, previous laminectomy) - Measure facet joint orientation and uncinate process hypertrophy - CT angiography if VA injury risk (revision, anomalous anatomy) **Dynamic Cervical Radiographs**: - Flexion-extension lateral views assess instability - >3.5mm translation or >11° angulation indicates instability - Kyphotic alignment (straight or reversed curve) is relative contraindication - Measure C2-C7 Cobb angle (normal 20-40° lordosis) **Preoperative Neurophysiology**: - Somatosensory evoked potentials (SSEPs) - posterior column function - Motor evoked potentials (MEPs) - corticospinal tract function - Baseline for intraoperative monitoring during decompression ## Surgical Planning **Level Selection**: - Include all stenotic levels causing cord compression on MRI - Extend UIV to first level with normal canal diameter (>14mm) - Extend LIV to first level with normal canal diameter - Common constructs: C3-C6, C3-C7, C4-C7 (most frequent) - Consider prophylactic decompression of borderline levels **Screw Trajectory Planning**: - Review lateral mass dimensions on axial CT (each level) - C3 has smallest lateral mass (may require 3.0mm screw) - C7 has largest lateral mass but anterior VA course - Plan Magerl (25/45) vs Anderson (10/30) based on anatomy - Identify any lateral mass fractures or previous screw holes **Fusion Strategy**: - Autograft from removed lamina/spinous processes (limited volume) - Allograft (morselized cancellous chips) to supplement - Demineralized bone matrix (DBM) as extender - BMP consideration (expensive, risk ectopic bone, seroma) - Posterolateral fusion bed between lateral masses bilaterally **Instrumentation Selection**: - Lateral mass screws: 3.5mm diameter (3.0mm if small lateral mass) - Screw length: 12-14mm (measure on CT, add 2mm for bicortical) - Rods: 3.5mm titanium, contoured to 20-40° lordosis - Locking screws and caps from manufacturer system - Consider C2 pedicle screws if extending to C2 (stronger than C2 lateral mass) ## Preoperative Optimization **Medical Optimization**: - Discontinue anticoagulation (warfarin 5 days, DOAC 48h) - Continue aspirin (no increased bleeding risk) - Optimize diabetic control (HbA1c <7%) - Nutritional assessment (albumin >3.5 g/dL for healing) - Smoking cessation minimum 4 weeks (fusion rate) **Consent Discussion**: - C5 palsy 5-10% (usually recovers 80-90% at 1 year) - Dural tear 5-8% (repair primarily, no long-term sequelae) - Spinal cord injury 0.2-0.4% (devastating, discuss thoroughly) - Vertebral artery injury <0.5% (stroke risk) - Infection 1-3%, epidural hematoma 1-2% (emergency re-exploration) ## Positioning and Preparation **Patient Position**: Prone position in Mayfield 3-pin head holder (4 finger-breadths above ears, 1cm above supraorbital ridge to avoid supraorbital nerve). Reverse Trendelenburg 15-20 degrees to reduce venous pressure. Shoulder tape traction caudally to expose C7-T1. Confirm neutral cervical alignment on lateral fluoroscopy - avoid flexion (cord compression) or extension (reduces canal diameter). **Padding and Monitoring**: - Chest rolls shoulder to iliac crest (allows abdominal free breathing) - Padded knee and ankle supports (avoid peroneal nerve compression) - Arms tucked at sides or on arm boards <90° abduction - Eyes protected with ophthalmic ointment and taped closed - Foley catheter for cases >2 hours - Neuromonitoring electrodes (SSEPs, MEPs) after positioning ### Step 1: Positioning and Exposure Planning Positioning and Exposure Planning: Patient prone in Mayfield head holder with neck in NEUTRAL position - avoid flexion (cord compression) or extension (reduces canal diameter). Reverse Trendelenburg 15 degrees reduces epidural venous bleeding. Shoulder tape traction caudally exposes C7-T1. Mark midline with palpable spinous processes. Confirm C2 (largest palpable), C6 (carotid tubercle level), C7 (prominent). Use lateral fluoroscopy to mark skin incision from planned UIV to LIV. **Technical Tip**: EXAM KEY: Neutral neck position critical - excessive flexion can cause spinal cord compression during surgery. Reverse Trendelenburg reduces venous pressure by 40-50%. Accurate level identification ESSENTIAL - count from C2 (axis) which is first palpable spinous process below occiput. Wrong level surgery is NEVER EVENT. - Spinal cord compression from positioning (flexion >10°) - Wrong level exposure (40% error with palpation alone in obesity) - Excessive venous bleeding (inadequate reverse Trendelenburg) - Brachial plexus injury from shoulder taping (>2kg traction) - Eye injury (pressure on globe from face positioning) ### Step 2: Midline Incision and Subperiosteal Exposure Midline Incision and Subperiosteal Exposure: Midline incision through skin and subcutaneous tissue. Identify avascular midline raphe between trapezius muscles. Incise down to nuchal ligament. Subperiosteal dissection with Cobb elevator staying on bone - detach semispinalis cervicis and multifidus from C2 spinous process and laminae. Expose lateral masses bilaterally to lateral edge of lateral mass (facet joint). Preserve C2 nerve root (greater occipital nerve) crossing C1-2 if possible. Self-retaining retractors maintain exposure. **Technical Tip**: EXAM KEY: Subperiosteal dissection preserves segmental muscle innervation and reduces bleeding. Lateral dissection limit is LATERAL EDGE OF FACET JOINTS - going more lateral risks vertebral artery (1.5-2mm from lateral mass edge in foramen transversarium). Preserve C2 nerve if exposing C1-2 to avoid occipital neuralgia (15-20% if violated). - Vertebral artery injury (lateral dissection beyond facet edge) - Excessive bleeding from muscle (300-500mL typical blood loss) - C2 nerve injury causing occipital neuralgia (frontal/vertex pain) - Dural tear from aggressive subperiosteal dissection - Inadequate lateral exposure (insufficient decompression) ### Step 3: Level Confirmation with Fluoroscopy Level Confirmation with Fluoroscopy: Place marker (spinal needle or instrument) on spinous process and confirm level with lateral C-arm fluoroscopy. In cervical spine, nerve roots EXIT ABOVE their numbered vertebra (C5 root exits C4-5, unlike lumbar where L5 exits L5-S1). Identify C2 spinous process (bifid), C7 (longest, non-bifid). Count carefully from C2. Mark planned laminectomy levels with electrocautery on laminae. **Technical Tip**: EXAM KEY: Wrong level surgery is NEVER EVENT. Cervical spine has 8 nerve roots but 7 vertebrae - C8 root exits C7-T1. Always confirm level BEFORE laminectomy. Palpation alone has 40% error rate in obese patients. Use lateral fluoroscopy with radiopaque marker on each level before decompression. - Wrong level laminectomy (medicolegal catastrophe) - Radiation exposure to surgeon and staff (use lead, distance) - C-arm collision with patient/head holder (coordinate with radiology tech) - Misidentification of C2 vs occiput or C1 ### Step 4: Lateral Mass Screw Insertion Lateral Mass Screw Insertion: Insert lateral mass screws BEFORE laminectomy for maximum stability. Entry point: CENTER of lateral mass between superior and inferior articular processes. Two main techniques: MAGERL (25° lateral, 45° cephalad toward opposite eye socket) or ANDERSON (10° lateral, 30-40° cephalad parallel to facet). Drill 12-14mm depth. Palpate 4 walls with ball-tip probe checking for breach. Typical screw: 3.5mm diameter x 12-14mm length. Bicortical purchase not necessary. Start at lowest level and work cephalad. **Technical Tip**: EXAM KEY: Magerl trajectory 25/45 (higher angles) has LARGER safe zone but risks nerve root injury if too medial. Anderson trajectory 10/30 (lower angles) is SAFER for nerve root but smaller margin for error. Key danger: MEDIAL breach >4mm = nerve root injury, LATERAL breach = vertebral artery (VA 1.5-2mm lateral to lateral mass). Palpate all 4 walls before screw insertion. - Medial breach causing nerve root injury (2-5% incidence) - Lateral breach causing vertebral artery injury (0.3-0.5%, catastrophic) - Anterior breach into carotid sheath or esophagus (rare) - Screw loosening in osteoporotic bone (augment with PMMA if needed) - Facet joint violation causing neck pain ### Step 5: Laminectomy - Progressive Posterior Decompression Laminectomy - Progressive Posterior Decompression: Start laminectomy at most stenotic level. Use high-speed burr with footplate attachment to thin lamina from midline laterally, staying in epidural space. Thin to eggshell thickness. Identify ligamentum flavum (thick yellow elastic tissue, hypertrophied in stenosis to 7-10mm). Use Kerrison rongeurs to complete laminectomy removing lamina, spinous process, and ligamentum flavum. Work from cephalad to caudad. Undercut facets bilaterally for lateral recess and foraminal decompression. Preserve >50% of facet joint to avoid iatrogenic instability. **Technical Tip**: EXAM KEY: Ligamentum flavum is 3-5mm thick (hypertrophies to 7-10mm in stenosis), identified by YELLOW color. Dura is immediately anterior (0-2mm gap). Thin lamina with burr FIRST before rongeur to avoid dural injury. If OPLL present, leave ossified dura intact - attempting removal risks catastrophic CSF leak and cord injury (CSF fistula rate 50% if ossified dura violated). - Dural tear (5-8% incidence, higher with revision or OPLL) - Spinal cord injury from instrument penetration anteriorly - Epidural venous plexus bleeding (Batson's plexus, engorged if inadequate positioning) - Inadequate decompression laterally (residual foraminal stenosis) - Excessive facet resection causing iatrogenic instability ### Step 6: Foraminal Decompression Foraminal Decompression: Undercut medial aspect of facet joints bilaterally using Kerrison rongeurs. Remove 25-50% of facet joint medial portion to decompress nerve root in foramen. Nerve roots exit ABOVE pedicle at each level (C5 root exits above C5 pedicle in C4-5 foramen). Confirm adequate decompression by passing micro nerve hook into foramen - should slide freely without resistance. Avoid resecting >50% of facet which causes iatrogenic instability requiring fusion extension. **Technical Tip**: EXAM KEY: Cervical foraminal stenosis often caused by UNCOVERTEBRAL JOINT (joints of Luschka) osteophytes anteriorly. May need anterior approach (ACDF) if predominantly anterior compression. Safe foraminal decompression: remove medial 25-50% of facet, stay on BONE (not soft tissue laterally where VA lies 1.5-2mm away). Nerve hook should pass freely without resistance. - Nerve root injury from excessive retraction or direct trauma - Vertebral artery injury (lateral dissection beyond bone edge) - Excessive facet resection (>50%) causing instability - Inadequate decompression leaving residual radiculopathy - Nerve root avulsion (gentle technique essential) ### Step 7: Rod Contouring and Placement Rod Contouring and Placement: Contour rods to match patient's cervical lordosis (normal 20-40 degrees C2-C7 Cobb angle). Goal is to MAINTAIN or RESTORE lordosis - kyphotic alignment leads to poor outcomes and swan-neck deformity. Connect rods to lateral mass screws bilaterally. Use rod holders to provisionally seat rods. May need to compress or distract at individual levels to achieve optimal alignment. Ensure rods are fully seated in screw heads before final tightening. Compression loads bone graft. **Technical Tip**: EXAM KEY: Cervical lordosis MUST be maintained - post-laminectomy kyphosis occurs in 10-20% without fusion. Normal cervical lordosis 20-40° (C2-C7 Cobb angle). Rod diameter typically 3.5mm titanium. Compression across levels loads bone graft and closes laminectomy defect. Avoid excessive compression causing foraminal stenosis (nerve root impingement). - Loss of lordosis causing kyphotic malalignment (swan-neck deformity) - Rod-screw interface failure (inadequate seating) - Neurovascular injury during rod passage (especially first rod) - Malposition causing junctional kyphosis at UIV or LIV - Excessive compression causing foraminal stenosis ### Step 8: Decortication and Bone Grafting Decortication and Bone Grafting: Decorticate lateral masses bilaterally with high-speed burr or osteotome to expose bleeding cancellous bone. Remove outer cortex only - preserve medial wall adjacent to spinal canal. Decorticate between lateral mass screws creating fusion bed. Pack morselized bone graft (local autograft from removed lamina/spinous processes plus allograft or demineralized bone matrix) over lateral masses and between screws. Goal: posterolateral fusion mass connecting instrumented levels. BMP consideration (expensive AU$3000-5000, ectopic bone risk). **Technical Tip**: EXAM KEY: Fusion is REQUIRED after laminectomy to prevent progressive kyphosis (up to 21% without fusion vs 0-2% with fusion). Autograft from removed bone is excellent but limited volume (30-50cc). Posterolateral fusion between lateral masses is gold standard. BMP accelerates fusion (faster by 2-3 months) but risk ectopic bone, seroma, dysphagia, expensive. - Inadequate fusion bed preparation (pseudarthrosis 5-10%) - BMP-related seroma requiring drainage (5-8% if BMP used) - Graft dislodgement into canal (rare, catastrophic cord compression) - Ectopic bone formation causing radiculopathy - Excessive decortication causing lateral mass fracture ### Step 9: Final Tightening and Imaging Final Tightening and Imaging: Perform final tightening of all set screws and locking caps in sequential manner to avoid construct strain. Torque to manufacturer specifications (typically 80-100 in-lb for 3.5mm systems). Obtain intraoperative lateral and AP fluoroscopy or plain radiographs to confirm: 1) Screw positions (no breaches), 2) Rod position and alignment, 3) Cervical lordosis maintained, 4) No hardware prominence. Address any malpositioned screws immediately - medial breach >4mm requires revision. **Technical Tip**: EXAM KEY: Inadequate final tightening is common cause of hardware failure. Final imaging is MANDATORY to confirm correct screw placement and alignment. Post-op CT often performed to verify screw position - medial breach >4mm requires revision (nerve root risk). C5 palsy can manifest in recovery (delayed onset 24-48h) - monitor motor function hourly x 24h. - Screw loosening from inadequate torque (under-tightening) - Unrecognized screw malposition (medial or lateral breach) - Hardware prominence posteriorly causing wound breakdown - Junctional kyphosis at UIV or LIV (extend fusion if malaligned) - Loss of lordotic correction ### Step 10: Meticulous Hemostasis Meticulous Hemostasis: Achieve hemostasis with bipolar electrocautery focusing on epidural venous plexus, muscle edges, and bone surfaces. Use thrombin-soaked gelfoam over exposed dura. Bone wax on bleeding bone edges (use sparingly - inhibits fusion). Ensure no active bleeding before closure - cervical epidural hematoma is devastating complication (1-2% incidence). Consider tranexamic acid (TXA) 1g load + 1g over 8h to reduce blood loss by 30-40%. Irrigate copiously with antibiotic solution (1g vancomycin in 1L saline). **Technical Tip**: EXAM KEY: Epidural hematoma causing cord compression is surgical EMERGENCY (1-2% incidence). Risk factors: multilevel surgery, bleeding disorders, epidural venous engorgement, inadequate hemostasis. Post-op neuro checks q1h first 24h. Any deterioration requires urgent MRI and emergent decompression if hematoma confirmed (within 6h to prevent permanent deficit). - Epidural hematoma with cord compression (1-2%, emergency decompression) - Excessive bleeding requiring transfusion (mean blood loss 300-500mL) - Hematoma causing wound dehiscence (superficial collection) - Seroma formation (especially if BMP used) - Inadequate hemostasis necessitating re-exploration ### Step 11: Layered Closure with Drain Layered Closure with Drain: Place 10Fr round drain in epidural space if extensive dissection or oozing (>5 levels, revision, BMP use). Bring drain out through separate stab incision lateral to main wound. Close in layers: 1) Muscle and nuchal ligament with 0 Vicryl interrupted sutures (restore posterior tension band), 2) Deep dermis with 2-0 Vicryl, 3) Subcuticular closure with 3-0 Monocryl, 4) Skin glue or steri-strips. Apply sterile dressing. Keep drain for 24-48h or until output <50mL/24h. Rigid cervical collar optional (many surgeons avoid with instrumented fusion). **Technical Tip**: EXAM KEY: Drain reduces hematoma risk but increases infection risk slightly - use selectively for multilevel cases (>4 levels), revision, BMP cases. Collar NOT required with instrumented fusion (immediately stable construct). Early mobilization (day 1) recommended - reduces complications. Fusion takes 3-6 months cervical spine (faster than lumbar 6-12 months). CT at 3 months to assess bridging bone. - Wound infection (1-3% incidence, higher if drain >48h) - CSF leak if dural tear not repaired (post-op headache, clear drainage) - Drain site infection or persistent drainage - Wound dehiscence from hematoma or infection - Seroma requiring aspiration ### Step 12: Post-operative Monitoring and Management Post-operative Monitoring and Management: Neurological checks hourly for first 24 hours focusing on motor and sensory function. C5 palsy is most common nerve root injury post-cervical decompression (5-10% incidence) - manifests as deltoid/biceps weakness with or without pain. Usually delayed onset (24-48h). Mechanism: nerve root tethering with cord drift posteriorly after decompression. Management is expectant - most recover over 3-12 months (80-90% at 1 year). Obtain post-op cervical spine radiographs (AP, lateral) on day 1 to confirm alignment and hardware position. Early mobilization unless C5 palsy severe. **Technical Tip**: EXAM KEY: C5 PALSY pathophysiology: spinal cord drift posteriorly after decompression (increased canal diameter) causes traction on C5 root which is shortest (25-30mm), most horizontal (90° from cord), and has least mobility of cervical roots. Risk factors: large decompression (>3 levels), significant pre-op cord compression, posterior cord shift >3mm on MRI, combined anterior-posterior surgery. Usually RECOVERS spontaneously (80-90% at 1 year). EMG at 3 weeks if no improvement to confirm axonal injury vs neurapraxia. - C5 palsy (5-10%, delayed onset 24-48h, usually recovers) - Epidural hematoma (1-2%, emergency if cord compression) - Respiratory compromise from anterior soft tissue swelling - Hardware-related dysphagia (rare with posterior approach) - Neurological deterioration requiring urgent imaging ## Complication Rates Summary **Neurological Complications**: - C5 palsy: 5-10% (usually recovers 80-90%) - Spinal cord injury: 0.2-0.4% (devastating, permanent) - Nerve root injury: 2-5% (from screw malposition) **Hemorrhagic Complications**: - Epidural hematoma: 1-2% (surgical emergency) - Vertebral artery injury: <0.5% (stroke risk) - Mean blood loss: 300-500mL **Mechanical Complications**: - Screw malposition: 2-5% (medial/lateral breach) - Post-laminectomy kyphosis: 10-20% without fusion, <2% with fusion - Pseudarthrosis: 5-10% (smokers higher risk) - Hardware failure: 1-3% (loosening, breakage) **Infectious Complications**: - Wound infection: 1-3% (superficial vs deep) - Discitis/osteomyelitis: <1% (delayed, weeks post-op) - Meningitis: <0.5% (if dural tear) **Other Complications**: - Dural tear: 5-8% (higher in revision, OPLL) - Dysphagia: rare with posterior approach (<1%) - Adjacent segment disease: 2-3% per year - Axial neck pain: 15-20% (myofascial, muscular) **Immediate Post-operative (0-24h)**: - Neurological checks hourly x 24h (motor/sensory all extremities) - Monitor for C5 palsy (deltoid/biceps weakness, delayed onset 24-48h) - Watch for epidural hematoma (acute neuro deterioration = emergency MRI) - Elevate head of bed 30-45° to reduce swelling - Drain output monitoring (remove when <50mL/24h, typically 24-48h) - Pain management: multimodal (paracetamol, NSAIDs, opioids PRN) **Early Mobilization (1-7 days)**: - Mobilize day 1 with physiotherapy (no collar needed with instrumented fusion) - Log-roll for bed mobility first 48h (comfort, not stability concern) - Deep breathing exercises and incentive spirometry (prevent atelectasis) - VTE prophylaxis: sequential compression devices, mobilization, chemical prophylaxis (enoxaparin 40mg daily) if low bleeding risk - Post-op radiographs (AP, lateral cervical spine) day 1 to confirm alignment and hardware **Discharge Planning (2-5 days typical)**: - Discharge when: mobilizing independently, pain controlled oral medications, no neurological deterioration, drain removed, wound dry - BLT precautions (bending, lifting >5kg, twisting) x 6 weeks - Wound care: keep dry x 10 days, remove sutures/staples at 10-14 days - Red flags: fever >38.5°C, wound drainage, neurological change, severe pain - Follow-up: 2 weeks (wound check), 6 weeks, 3 months, 6 months, 1 year **Rehabilitation Protocol**: - Week 0-6: BLT precautions, gentle ROM exercises (active, no resistance) - Week 6-12: Progressive strengthening, isometric cervical exercises - Month 3+: Full activity as tolerated if fusion progressing on imaging - Return to work: sedentary 4-6 weeks, manual labor 3-6 months (after fusion confirmed) - Driving: when comfortable turning head (no collar), off opioids, 2-4 weeks typical **Imaging Follow-up**: - Post-op day 1: AP and lateral cervical radiographs (baseline alignment, hardware) - 6 weeks: Cervical radiographs (alignment, hardware, early fusion assessment) - 3 months: CT cervical spine (assess fusion, bridging bone formation) - 6 months: Flexion-extension radiographs (assess fusion stability) - 1 year: CT if pseudarthrosis concern, otherwise clinical assessment **Fusion Assessment**: - Radiographic fusion: bridging bone across fusion levels on CT - Dynamic fusion: <2mm translation or <5° angulation on flexion-extension - Time to fusion: 3-6 months cervical spine (faster than lumbar) - Pseudarthrosis if no bridging bone at 12 months on CT ## References 1. **Hilibrand AS, Carlson GD, Palumbo MA, Jones PK, Bohlman HH.** Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. *J Bone Joint Surg Am.* 1999;81(4):519-528. doi:10.2106/00004623-199904000-00009 - Landmark study establishing natural history of adjacent segment disease after ACDF, influential for multilevel disease surgical planning 2. **Heller JG, Edwards CC 2nd, Murakami H, Rodts GE.** Laminoplasty versus laminectomy and fusion for multilevel cervical myelopathy: an independent matched cohort analysis. *Spine.* 2001;26(12):1330-1336. doi:10.1097/00007632-200106150-00011 - Prospective comparison showing superior outcomes with laminoplasty vs laminectomy-fusion for multilevel myelopathy 3. **Anderson PA, Henley MB, Grady MS, Montesano PX, Winn HR.** Posterior cervical arthrodesis with AO reconstruction plates and bone graft. *Spine.* 1991;16(3 Suppl):S72-79. doi:10.1097/00007632-199103001-00012 - Original description of Anderson lateral mass screw technique (10° lateral, 30° cephalad trajectory) 4. **Magerl F, Seemann P-S.** Stable posterior fusion of the atlas and axis by transarticular screw fixation. In: Kehr P, Weidner A, eds. *Cervical Spine I.* Springer-Verlag; 1987:322-327. - Seminal description of Magerl lateral mass screw technique (25° lateral, 45° cephalad), established safe zone concept 5. **Sakaura H, Hosono N, Mukai Y, Ishii T, Iwasaki M, Yoshikawa H.** C5 palsy after decompression surgery for cervical myelopathy: review of the literature. *Spine.* 2003;28(21):2447-2451. doi:10.1097/01.BRS.0000090833.96168.3F - Comprehensive review of C5 palsy pathophysiology, risk factors, and natural history showing 80-90% spontaneous recovery 6. **Kristof RA, Kiefer T, Thees C, Schramm J, Weinzierl MR.** Differences between laminectomy and laminoplasty: influence on sagittal alignment and range of motion in multilevel cervical myelopathy. *Clin Spine Surg.* 2009;22(6):391-397. doi:10.1097/BSD.0b013e31818e0027 - Biomechanical study comparing kyphosis rates: laminectomy without fusion 21% vs laminoplasty 0% at 2-year follow-up 7. **Fehlings MG, Barry S, Kopjar B, et al.** Anterior versus posterior surgical approaches to treat cervical spondylotic myelopathy: outcomes of the prospective multicenter AOSpine North America CSM study in 264 patients. *Spine.* 2013;38(26):2247-2252. doi:10.1097/BRS.0000000000000047 - Prospective multicenter trial showing equivalent neurological outcomes but different complication profiles: posterior higher C5 palsy, anterior higher dysphagia 8. **Yoshihara H, Passias PG, Errico TJ.** Screw-related complications in the subaxial cervical spine with the use of lateral mass versus cervical pedicle screws: a systematic review. *J Neurosurg Spine.* 2013;19(5):614-623. doi:10.3171/2013.4.SPINE12836 - Meta-analysis of 3,161 lateral mass screws showing 2.9% nerve root injury, 0.3% vertebral artery injury, 1.7% malposition 9. **Kawaguchi Y, Kanamori M, Ishihara H, et al.** Minimum 10-year followup after en bloc cervical laminoplasty. *Clin Orthop Relat Res.* 2003;411:129-139. doi:10.1097/01.blo.0000069888.31220.a3 - Long-term outcome study showing laminoplasty maintains decompression with lower kyphosis rate than historical laminectomy without fusion 10. **Emery SE, Bohlman HH, Bolesta MJ, Jones PK.** Anterior cervical decompression and arthrodesis for the treatment of cervical spondylotic myelopathy. Two to seventeen-year follow-up. *J Bone Joint Surg Am.* 1998;80(7):941-951. doi:10.2106/00004623-199807000-00002 - Classic long-term study establishing ACDF outcomes for cervical myelopathy, influential for determining when anterior vs posterior approach indicated

Posterior Cervical Laminectomy and Fusion

Posterior Cervical Laminectomy and Fusion