import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Travels in tracheoesophageal groove - RIGHT side more vulnerable (loops under subclavian at T1-2, ascends obliquely). LEFT side loops predictably under aortic arch. **Protection**: Left-sided approach preferred. Avoid retractor placement in tracheoesophageal groove. Endotracheal tube pressure monitoring - deflate/reposition q30min. Intraoperative neuromonitoring if revision/multilevel surgery. **Location**: Exits vagus at C3 level, travels deep to carotid to pierce thyrohyoid membrane. At risk with high approaches (C3-4, C2-3) or excessive superior retraction. **Protection**: Dissect only to level of surgical exposure required. Gentle superior retraction with handheld Cloward retractors. Avoid monopolar diathermy near carotid sheath above C4. **Location**: Enters transverse foramen C6 (90%) or C5 (8%). Courses 3mm lateral to uncovertebral joint. Anomalous course in 5% (medial deviation). **Protection**: Limit lateral dissection to medial border of uncinate process. Preoperative CTA if revision surgery or dysplastic anatomy. Angled curettes directed medially only. Uncovertebral drilling with 3mm diamond burr at 45° trajectory. **Location**: Average AP diameter cervical canal 14mm (range 10-20mm). Cord occupies 12mm - CSF 1mm anterior. Stenotic canal means minimal safety margin with instruments. **Protection**: Decompress lateral-to-medial sequence. Kerrison rongeurs bite away from cord (upbiting). Trial spacer before final implant - oversizing risks cord compression. Intraoperative SSEPs/MEPs for stenotic canals or ossification of PLL. **Location**: Immediately medial to dissection plane. Thin wall (3mm) highly vulnerable to retractor pressure, diathermy thermal injury, or sharp dissection. **Protection**: Handheld retraction initially until NG tube palpated. Smooth blade retractors (not teeth). Retract esophagus gently medially - limit pressure (60-80mmHg max). Irrigate frequently. Bipolar only near midline. Methylene blue swallow test if concern. ## Primary Indications **Absolute Indications** - Progressive cervical myelopathy with cord compression (modified JOA score decline) - Cervical radiculopathy failing 6-12 weeks conservative management with MRI-confirmed nerve root compression - Cervical kyphotic deformity with anterior column deficiency requiring reconstruction - Post-traumatic cervical instability (facet disruption, ALL/disc injury) requiring stabilization - Anterior cervical tumor/infection requiring corpectomy and reconstruction **Relative Indications** - Cervical radiculopathy with concordant imaging and high-demand occupation - Multilevel cervical spondylosis with predominant axial neck pain (controversial - consider arthroplasty) - Soft disc herniation with persistent radicular symptoms despite optimized non-operative care - Adjacent segment disease following prior cervical fusion **Contraindications** - **Absolute**: Active systemic infection, severe osteoporosis (DEXA T-score less than -3.5), medical instability - **Relative**: Multilevel disease (greater than 3 levels - consider hybrid constructs), smoker (2.7x pseudarthrosis risk), significant dysphagia baseline, ankylosing spondylitis (avoid through fused segments) ## Preoperative Planning Essentials **Imaging Analysis** - **MRI**: T2 signal changes in cord (myelomalacia poor prognosis), disc hydration, foraminal stenosis grade - **CT**: Assess ossification of PLL (40% Asian population), uncovertebral hypertrophy, facet arthropathy - **Flexion-extension radiographs**: Document instability (greater than 3mm translation or greater than 11° angulation) - **CTA**: If revision surgery (scar tissue distorts anatomy) or vascular anomaly suspected **Patient Optimization** - Smoking cessation 8 weeks minimum (proven 3x fusion rate improvement) - Diabetic HbA1c less than 7.5% (wound healing, infection risk reduction) - BMI optimization - obesity associated with higher dysphagia, revision rates - Discontinue NSAIDs 1 week preoperatively (theoretical fusion concern) **Graft and Instrumentation Selection** - **Autograft iliac crest**: Gold standard fusion (98% single-level) but donor site pain 20% - **Allograft structural**: Equivalent fusion with anterior plating (95% vs 98%), no donor morbidity - **PEEK cage with demineralized bone matrix**: Contemporary standard - subsidence risk 5-8% - **Anterior cervical plate**: Reduces pseudarthrosis 3-level from 44% to 8%, angular kyphosis - **Zero-profile devices**: Standalone cage with integrated screws - lower dysphagia (12% vs 28% at 3 months) ## Cervical Spine Anatomy **Surface Landmarks for Skin Incision** - C2-3: Angle of mandible (5cm superior to thyroid cartilage) - C3-4: Thyroid cartilage superior margin - C4-5: Cricoid cartilage (easily palpable landmark) - C5-6: Carotid tubercle (Chassaignac tubercle on C6 transverse process) / omohyoid crossing - C6-7: Suprasternal notch (2 fingerbreadths superior) - C7-T1: Suprasternal notch level **Anterior Cervical Fascial Layers** 1. **Skin/subcutaneous tissue**: 5-8mm thickness, transverse skin incision follows Langer lines (superior cosmesis) 2. **Platysma**: Thin muscle layer, divide in line with fibers (vertical) to expose deep cervical fascia 3. **Superficial layer deep cervical fascia**: Invests SCM and strap muscles 4. **Middle layer (pretracheal fascia)**: Encloses thyroid, trachea, esophagus - the "visceral column" 5. **Deep layer (prevertebral fascia)**: Directly on anterior longitudinal ligament - surgical target **Critical Neurovascular Relationships** *Carotid Sheath Contents* (retracted laterally en bloc) - Common carotid artery (medial to SCM, pulsatile landmark) - Internal jugular vein (lateral to artery) - Vagus nerve (posterior between vessels - injury causes hoarseness) *Visceral Column* (retracted medially) - Trachea (palpate air, endotracheal cuff) - Esophagus (posterior to trachea, NG tube palpation confirms) - Thyroid gland (isthmus crosses midline at C6-7, may require division for C7-T1) - Recurrent laryngeal nerve (in tracheoesophageal groove - NOT VISUALIZED) **Intervertebral Disc Anatomy** - **Anterior annulus**: 3mm thick, resists anterior graft extrusion (preserve if intact) - **Nucleus pulposus**: Degenerative disc has desiccated nucleus, easier discectomy - **Posterior annulus**: Thin (1mm), often attenuated with herniation - **Posterior longitudinal ligament (PLL)**: 2-3mm thick midline, thins laterally over uncovertebral joints - **Uncovertebral joints (Luschka)**: Lateral margin of disc space, vertebral artery 3mm lateral - **Neural foramen**: Bounded anteriorly by uncinate, posteriorly by facet, inferiorly by pedicle ## Positioning and Preparation **Patient Position** - Supine with shoulder roll to extend neck (improve lordosis, open disc spaces) - Head in neutral rotation (avoid rotation - distorts anatomy, stretches vertebral artery) - Slight reverse Trendelenburg (reduce venous pressure, improve exposure) - Arms tucked, secured at sides with padding (allow lateral C-arm access) - Gardner-Wells tongs or horseshoe headrest for controlled extension (optional) **Approach Side Selection** - **Left side preferred**: Recurrent laryngeal nerve more predictable course (1-2% injury vs 5-8% right) - **Right side considerations**: Surgeon left-handed, prior left neck surgery/radiation, thyroid pathology - **Bilateral approach**: Reserved for very wide corpectomies or tumor extirpation **Imaging and Localization** - C-arm positioned on patient's right (surgeon operates from right side for left approach) - Scout lateral radiograph confirms level - count from C2 (axis, prominent spinous process) - Skin marker (21G needle) at desired level - adjust incision accordingly ## Step-by-Step Operative Technique ### Step 1: Skin Incision and Platysma Division Transverse skin incision along Langer lines (skin crease) 4-5cm length centered over palpated disc level. Single-level: 4cm. Two-level: 5cm. Incise through dermis with 15-blade knife. Infiltrate with 1:200,000 epinephrine in local anesthetic for hemostasis. Divide platysma in line with muscle fibers (oblique/vertical) using monopolar cautery. Subplatysmal flaps raised superiorly and inferiorly 1cm using Metzenbaum scissors to improve exposure. **Technical Pearl**: Transverse incision provides superior cosmesis and extensile exposure for 2-3 levels from single incision. Place incision at mid-level for two-level surgery (i.e., C5-6 incision for C5-7 fusion). Avoid placement at exact disc level - this limits inferior extension. - External jugular vein injury (courses obliquely across SCM) - ligate if divided - Anterior jugular veins (medial to SCM) - preserve or ligate branches - Overly vertical incision risks keloid formation, poor cosmesis ### Step 2: Deep Cervical Fascia Division and Blunt Dissection Palpate SCM lateral border and carotid pulsation. Divide investing layer of deep cervical fascia along medial border of SCM using knife or scissors. Identify correct tissue plane between carotid sheath (laterally, pulsatile) and visceral column (medially, trachea palpable). Insert index finger bluntly between these structures and develop plane with gentle spreading - structures separate easily in correct plane. Finger sweeps superiorly and inferiorly opening space to vertebral bodies. Omohyoid muscle (crossing obliquely at C5-6) retracted superiorly or divided between clips if obstructing. **Technical Pearl**: Blunt dissection with finger is SAFEST - respects natural tissue planes and warns of aberrant anatomy. If plane is difficult, likely too anterior (in strap muscles) or too lateral (against carotid). Correct plane is essentially bloodless. Thyroid vessels (superior thyroid artery at C4-5, middle thyroid vein at C6) may cross midline - ligate with clips or bipolar. - Recurrent laryngeal nerve injury (in tracheoesophageal groove) - NEVER retract in midline - Sympathetic chain (on prevertebral fascia lateral) - injury causes Horner syndrome - Esophageal perforation - excessive force during medial retraction ### Step 3: Longus Colli Muscle Dissection and Retractor Placement Palpate anterior surface of vertebral bodies and midline. Incise prevertebral fascia vertically in midline using monopolar cautery. Elevate longus colli muscles bilaterally off anterior vertebral bodies using monopolar or Cobb elevator - detach 1.5cm bilaterally to allow retractor blade placement. Self-retaining retractors (Caspar or Cloward) with deep blades (15mm) placed under longus colli bilaterally - sharp teeth engage vertebral bodies above and below operative level. Adjust retractors to center disc space in field. Gentle medial retraction of esophagus with smooth blade (Army-Navy or Cloward handheld retractor). **Technical Pearl**: Longus colli dissection defines SAFE LATERAL LIMITS - do not extend past this boundary or risk vertebral artery injury. Retractor blade teeth should engage vertebral body bone, not disc space (risks retractor migration, spinal cord injury). Test retractor stability before proceeding. Monitor retractor pressure on esophagus - deflate endotracheal cuff intermittently to reduce total compression. - Vertebral artery injury (lateral to longus colli 3mm) - torrential bleeding, stroke risk - Spinal cord injury (retractor blade slips posteriorly through disc) - catastrophic - Esophageal pressure necrosis (excessive retraction pressure greater than 120 minutes) - delayed perforation ### Step 4: Localization Radiograph Insert 21G spinal needle into center of disc space under direct vision - angle slightly caudad to stay parallel with disc. Obtain lateral C-arm radiograph confirming correct level. Count vertebrae from C2 (axis). If incorrect level identified, reposition retractors. Mark operative level with cautery scratch on vertebral body for reference. Remove needle. **Technical Pearl**: Wrong-level surgery is NEVER EVENTS. Count from C2 proximally (easily identified on lateral) and C7 (first vertebra below shoulder) distally - triangulate. C3-4 and C4-5 look similar radiographically. Save image as documentation. If any doubt, obtain AP view (lateral masses numbered). - Wrong-level surgery (medicolegal catastrophe) - systematic verification mandatory - Needle penetration through disc into canal - keep insertion superficial (3-4mm) ### Step 5: Anterior Discectomy Mark rectangular window in anterior annulus with cautery - 14mm width (vertebral body width minus 2mm each side), 6mm height. Incise anterior annulus with 15-blade knife, creating 3-sided flap hinged inferiorly (or excise completely). Use pituitary rongeurs to remove nucleus pulposus sequentially - grasp and twist to extract disc fragments. Work centrally initially, then laterally and posteriorly. Remove cartilaginous endplates with angled curettes (20° and 30°) to expose bleeding subchondral bone (essential for fusion). Preserve subchondral bone plate integrity - overly aggressive curettage risks subsidence. **Technical Pearl**: Complete discectomy to POSTERIOR ANNULUS is critical. Insert ball probe through disc space to confirm posterior annulus palpable circumferentially. Incomplete discectomy leads to persistent symptoms and lower fusion rates. Angled curettes should scrape parallel to endplates - perpendicular force risks breach into vertebral body or canal. - Vertebral artery injury (overaggressive lateral discectomy beyond uncinate) - direct pressure, vascular consult - Endplate violation (excessive curettage) - graft subsidence, kyphosis, pseudarthrosis - Retained disc fragments (incomplete discectomy) - radiculopathy persistence ### Step 6: Posterior Osteophyte Removal and Neural Decompression Identify posterior longitudinal ligament (PLL) - white glistening band visible posteriorly. Using 2mm Kerrison rongeurs, resect posterior osteophytes (spondylophytes) from posterior vertebral body above and below. Bite bone with upbiting technique (rongeur jaws face away from spinal cord). For uncovertebral osteophytes (lateral spurs compressing nerve root in foramen), use 3mm diamond burr at 45° angle directed medially - drill under direct vision, protect vertebral artery (3mm lateral). Copious irrigation removes bone dust. Neural foramen adequately decompressed when ball probe passes freely into foramen bilaterally. **Technical Pearl**: Posterior decompression is RATE-LIMITING STEP for symptom relief. For myelopathy, resect PLL midline to visualize dural pulsations (confirms adequate decompression). For radiculopathy, foraminotomy to "see blue sky" (epidural veins visible when nerve free). Avoid pituitary rongeurs posteriorly - risks dural tear or cord injury. High-speed diamond burr safer than cutting burr (less aggressive). - Spinal cord injury (Kerrison bites cord) - upbiting technique mandatory, never downbite - Dural tear (overly aggressive PLL resection) - repair primarily, CSF leak risk - Vertebral artery injury (lateral foraminotomy) - limit drilling to medial half of foramen - Nerve root injury (foraminotomy) - instrument away from nerve, copious irrigation ### Step 7: Distraction and Disc Space Preparation Insert vertebral body spreader (Caspar distractor pins) into vertebral bodies 2cm lateral to midline (in safe zone medial to uncinate). Gradually distract disc space 1-2mm to restore disc height and tension ligaments. This improves visualization posteriorly and foraminal height. Measure disc space height (anterior, middle, posterior) with calibrated trial spacers. Prepare endplates with curettage ensuring parallel surfaces - remove all cartilage to bleeding bone. Morselized local bone from osteophytes placed in disc space as graft. **Technical Pearl**: Distraction should restore normal disc height (5-6mm at C5-6), not exceed physiologic height (risks facet distraction, ASD). Measure at anterior and posterior disc space - select graft 1mm larger than posterior measurement to restore lordosis (2-4° per level). Parallel endplates prevent subsidence and kyphosis. Over-distraction risks C5 palsy (nerve root tethering) - limit to 2mm. - C5 nerve palsy (excessive distraction tethers root) - rare but devastating complication 5% - Facet violation (over-distraction fractures facets) - instability, pain - Vertebral body fracture (distractor pin placement too lateral) - osteoporotic bone at risk ### Step 8: Interbody Graft or Cage Placement Select appropriately sized graft: structural allograft, autograft (iliac crest), or interbody cage (PEEK, titanium). For structural graft, fashion cortical-cancellous block 1mm larger than measured height, width to fill disc space (14mm typically). Contour lordotic angle 4-6° with rongeur or burr. For cage, pack with morselized autograft (local bone) or DBM. Insert graft under direct vision with impactor - central position in disc space verified. Graft should sit flush with anterior vertebral cortex or recessed 2mm. Remove distractor pins - graft should be stable with ligamentotaxis compression. **Technical Pearl**: Graft sizing is CRITICAL - undersized graft migrates (extrusion, pseudarthrosis), oversized graft causes cord compression or endplate fracture. Final implant should restore disc height and lordosis without excessive distraction. Stand-alone cages require 6° lordotic angle to prevent subsidence. Anterior position (flush to cortex) increases extrusion risk but improves lordosis; recessed position (2mm) reduces swelling but risks kyphosis. - Graft extrusion (undersized or anterior positioned) - dysphagia, esophageal erosion - Spinal cord compression (oversized graft) - immediate quadriparesis, emergency removal - Graft subsidence (endplate violation, osteoporosis) - kyphosis, pseudarthrosis - Vertebral artery injury (graft migrates laterally) - rare catastrophic complication ### Step 9: Anterior Cervical Plate Fixation (if used) Select appropriate plate length - spans one vertebral body above to one below (single-level). Position plate in midline over graft, touching superior endplate (within 5mm of disc space). Mark screw trajectories with AWL - 4 screws (2 per vertebra) positioned 3-4mm from endplate, 2mm from lateral edge. Drill pilot holes with 14mm drill guide - trajectory 12-15° caudad (away from adjacent disc). Measure depth with depth gauge. Insert self-tapping fixed-angle or variable-angle screws (typically 14mm length). Tighten screws sequentially to desired torque (8-10 Nm). Confirm bicortical purchase but not excessive length (greater than 18mm risks canal penetration). Locking screws prevent backout. **Technical Pearl**: Plate positioning is TECHNICAL KEY - too close to disc (less than 5mm) causes dysphagia from soft tissue impingement, too far (greater than 5mm) reduces stability. Screw trajectory must angle AWAY from adjacent disc (cranial screws angle cranially, caudal screws angle caudally) to prevent violation. Variable-angle screws accommodate kyphotic deformity. Zero-profile devices (cage with integrated screws) have 50% lower dysphagia rates at 3 months - consider for C5-6, C6-7. - Screw malposition (anterior blow-out) - esophageal injury, catastrophic bleeding if vertebral artery - Screw penetration into disc (wrong trajectory) - adjacent segment degeneration - Spinal canal penetration (excessive screw length) - cord injury, CSF leak - Plate prominence (greater than 3mm from bone) - dysphagia, esophageal erosion ### Step 10: Intraoperative Imaging Confirmation Obtain lateral C-arm fluoroscopy confirming: (1) Correct level, (2) Graft position within disc space, (3) Restoration of disc height and lordosis, (4) Plate position (if used), (5) Screw trajectories do not violate adjacent discs or canal. Obtain AP view confirming midline graft position, bilateral screw placement symmetric, no lateral graft migration. Save images for medicolegal documentation. If any concern, adjust hardware before closure. **Technical Pearl**: Final imaging is MANDATORY documentation. Lateral view: Trace posterior vertebral body line (should be smooth without step-off). Graft should restore lordotic curve. Anterior plate should be within 5mm of superior disc. AP view: Screws should be symmetric about midline. Graft centered (not biased to one side suggesting rotation). Compare to preoperative lordosis - should be maintained or improved. - Missed hardware malposition (proceed to closure) - requires reoperation - Inadequate decompression not recognized - persistent symptoms postoperatively ### Step 11: Hemostasis and Irrigation Remove self-retaining retractors carefully. Inspect wound for bleeding - meticulous hemostasis with bipolar cautery (avoid monopolar near esophagus). Irrigate wound copiously with 1-2L normal saline using pulsatile lavage. Re-inspect vertebral bodies and graft - ensure stable. Consider closed-suction drain (10Fr Blake) placed deep to platysma if extensive dissection or multilevel surgery (remove POD1). Avoid drain if minimal oozing - increases infection risk. **Technical Pearl**: Hemostasis is CRITICAL in cervical spine - hematoma causes airway compression (requires emergency intubation or evacuation). Bipolar coagulation of venous ooze from vertebral bodies, epidural veins. Do NOT place drain on esophagus (pressure necrosis). If drain used, secure to skin and attach to bulb suction (not gravity). Monitor drain output q2h postoperatively - greater than 100mL in first 4 hours warrants concern. - Postoperative hematoma (inadequate hemostasis) - airway emergency 0.5-2% of cases - Esophageal injury not recognized (thermal or mechanical) - delayed perforation (48-96h) - Drain erosion into esophagus (drain placed on midline) - catastrophic complication ### Step 12: Layered Wound Closure Approximate platysma with 2-0 Vicryl interrupted sutures (reestablish muscular layer). Close subcutaneous layer with 3-0 Vicryl running suture (bury knots to prevent palpability). Skin closure with 4-0 Monocryl running subcuticular suture for superior cosmesis (avoid staples). Apply Steri-Strips and transparent dressing. Avoid pressure from dressing on airway. **Technical Pearl**: Meticulous closure reduces seroma formation and scarring. Platysma closure is KEY layer - prevents subcutaneous seroma and improves cosmesis. Buried subcuticular closure avoids suture removal (patient convenience). Avoid circumferential dressings (neck compression risks airway). Some surgeons prefer delayed extubation or overnight intubation for multilevel surgery - discuss with anesthesia if airway edema concern. - Wound dehiscence (excessive tension) - rare with proper technique - Skin necrosis (overly tight closure) - transverse incision in skin crease minimizes this - Airway obstruction (immediate postoperative) - hematoma, edema, or recurrent laryngeal nerve palsy ## Intraoperative Complications ## Late Complications **Pseudarthrosis (Non-union)** - **Incidence**: Single-level 3-7%, two-level 12-18%, three-level 30-40% without instrumentation. Anterior plating reduces rates by 50%. - **Risk Factors**: Smoking (2.7x risk), multilevel fusion, allograft versus autograft, inadequate endplate preparation, NSAIDs, diabetes - **Recognition**: Persistent neck pain, radiculopathy recurrence. Flexion-extension radiographs show greater than 2mm motion at fused level. CT shows lack of bridging bone across graft-vertebra interface. - **Management**: Asymptomatic pseudarthrosis may not require revision (25% eventually fuse). Symptomatic: Revision ACDF with autograft, rhBMP-2, anterior plating. Consider posterior fusion (C3-7 lateral mass screws) if multilevel anterior failure. **Adjacent Segment Disease (ASD)** - **Incidence**: 2.9% per year, cumulative 25% at 10 years. Biomechanical stress transfer to adjacent disc. - **Prevention**: Maintain/restore cervical lordosis (reduces ASD risk). Consider cervical disc arthroplasty in younger patients (less than 50 years, single-level) - theoretical advantage (not proven). - **Management**: Conservative initially (PT, NSAIDs). If progressive, treat as primary cervical disease (ACDF or arthroplasty at adjacent level). ## Key Evidence Base **Landmark Trials** 1. **Smith & Robinson (1958)**: Original description of anterior cervical approach and interbody fusion technique - established ACDF as treatment for cervical disc disease 2. **Bohlman et al. (1993)**: Demonstrated 92% fusion rate with autograft and anterior plating versus 67% without plating for multilevel ACDF 3. **Hilibrand et al. (1999)**: Defined adjacent segment disease - 2.9% annual incidence, 25% cumulative at 10 years post-ACDF 4. **Wang et al. (2000)**: Meta-analysis showing fusion rates: autograft iliac crest 93%, allograft 88%, anterior plating improves both to 96-98% **Contemporary Outcomes** - **Fusion rates** (at 1 year with anterior plating): Single-level 95-98%, Two-level 90-95%, Three-level 85-90% - **Clinical success** (Odom criteria excellent/good): 85-90% for radiculopathy, 70-80% for myelopathy - **Return to work**: 75-80% at 6 months (radiculopathy), 60-70% at 1 year (myelopathy) - **Complication rates**: Overall 10-15%, major complications (reoperation, neurologic deficit) 2-3% **Graft Options Comparative Data** - **Autograft iliac crest**: Fusion 98%, donor site pain 20%, harvest time 20 minutes - **Allograft structural**: Fusion 95% (with plating), no donor morbidity, subsidence risk 8-12% - **PEEK cage + DBM**: Fusion 92-95%, subsidence 5-8%, radiolucent (MRI/CT compatible) - **rhBMP-2 (off-label)**: Fusion 98%, dysphagia risk increased 2x (soft tissue swelling), heterotopic ossification 18% **Plate versus No Plate** - Single-level: Fusion rates equivalent (95% vs 92%, p=0.08) - plating may be omitted if good endplate contact - Two-level: Plating improves fusion (90% vs 78%, p less than 0.01) and reduces kyphosis - Three-level: Plating mandatory - reduces pseudarthrosis from 44% to 8% **Arthroplasty versus Fusion (FDA IDE Trials)** - **Bryan, Prestige LP, ProDisc-C, Mobi-C trials**: Arthroplasty non-inferior for single-level disease at 5 years (NDI, VAS, neurologic success) - **Adjacent segment disease**: Arthroplasty shows 1.8% ASD reoperation versus 4.9% with ACDF at 7 years (Mobi-C trial) - **Limitations**: Longer-term data (greater than 10 years) lacking, higher cost, technically demanding, contraindications (facet arthritis, OPLL, instability) **Australian Context** - **Medicare MBS Items**: 40330 (single-level ACDF), 40333 (two-level), 40336 (three-level) - includes graft, instrumentation - **PBS Coverage**: Not applicable (devices not PBS listed) - **Australian Registry Data**: AOA National Spinal Register shows 15,000 ACDF procedures annually, infection rate 0.8%, reoperation 3.2% at 2 years ## Postoperative Care Protocol **Immediate Postoperative (0-24 hours)** - Monitor airway closely in PACU - risk of hematoma, edema, RLN palsy (keep anesthesia available) - Soft cervical collar for comfort (not structural - fusion relies on graft/plate, not collar) - Head of bed elevated 30° (reduce venous pressure, swelling) - Ice packs to anterior neck (reduce edema) - Diet: Clear liquids advance to soft diet as tolerated (dysphagia common 70% at 1 week) - Remove drain (if placed) when output less than 30mL per 8 hours (typically POD1) **Early Recovery (1-6 weeks)** - Mobilize immediately - no bed rest required - Collar weaned over 2 weeks (comfort only, not necessary for fusion) - Avoid heavy lifting (greater than 10 pounds), contact sports, extreme neck movements (extension/rotation) - Radiographs at 2 weeks (AP, lateral) - assess alignment, hardware position - Sutures removed 10-14 days (if non-absorbable used) - Return to desk work 2-4 weeks, manual labor 6-12 weeks **Late Recovery (6 weeks to 1 year)** - Flexion-extension radiographs at 3 months (assess early fusion) - CT scan at 6-12 months if concern for pseudarthrosis (persistent pain, no bridging bone on radiographs) - Physical therapy if neck stiffness, periscapular pain (common 40%) - Fusion confirmed radiographically: Bridging bone across graft, less than 2mm motion on flexion-extension, less than 5° angular change **VTE Prophylaxis** - Low risk surgery (1-2 hours, minimal blood loss) - early mobilization sufficient - High-risk patients (obesity BMI greater than 35, prior VTE, cancer, prolonged surgery greater than 3 hours) - sequential compression devices, LMWH (enoxaparin 40mg daily) starting POD1 (avoid preoperative dosing - hematoma risk) **Pain Management** - Multimodal analgesia: Paracetamol 1g QID, gabapentin 300mg TID (radicular pain) - Opioids as needed (oxycodone 5-10mg q4-6h) - minimize duration (risk dependency) - Avoid NSAIDs first 3 months (theoretical concern for fusion - controversial, weak evidence) - Ice therapy, gentle ROM exercises ## References 1. Smith GW, Robinson RA. The treatment of certain cervical-spine disorders by anterior removal of the intervertebral disc and interbody fusion. J Bone Joint Surg Am. 1958;40-A(3):607-624. *Original description of anterior cervical approach and interbody fusion technique - established ACDF as gold standard treatment for cervical disc disease.* 2. Bohlman HH, Emery SE, Goodfellow DB, Jones PK. Robinson anterior cervical discectomy and arthrodesis for cervical radiculopathy. Long-term follow-up of one hundred and twenty-two patients. J Bone Joint Surg Am. 1993;75(9):1298-1307. *Demonstrated 92% fusion rate with autograft and anterior plating versus 67% without plating for multilevel ACDF - established role of anterior instrumentation.* 3. 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. *Defined adjacent segment disease - 2.9% annual incidence, 25% cumulative at 10 years post-ACDF, established importance of maintaining cervical lordosis.* 4. Wang JC, McDonough PW, Endow KK, Delamarter RB. Increased fusion rates with cervical plating for two-level anterior cervical discectomy and fusion. Spine. 2000;25(1):41-45. *Meta-analysis showing fusion rates: autograft 93%, allograft 88%, anterior plating improves both to 96-98% - evidence base for routine plating in multilevel surgery.* 5. Riley LH 3rd, Skolasky RL, Albert TJ, Vaccaro AR, Heller JG. Dysphagia after anterior cervical decompression and fusion: prevalence and risk factors from a longitudinal cohort study. Spine. 2005;30(22):2564-2569. *Demonstrated dysphagia incidence 50-60% at 1 month, 12-14% at 12 months, identified multilevel surgery and prominent hardware as risk factors - established importance of low-profile implants.* 6. Fountas KN, Kapsalaki EZ, Nikolakakos LG, et al. Anterior cervical discectomy and fusion associated complications. Spine. 2007;32(21):2310-2317. *Comprehensive complication analysis: RLN palsy 1-8%, vertebral artery injury 0.3-0.5%, postoperative hematoma 0.5-2%, esophageal injury 0.1-0.25% - established complication benchmarks for quality improvement.* 7. Yue WM, Brodner W, Highland TR. Long-term results after anterior cervical discectomy and fusion with allograft and plating: a 5- to 11-year radiologic and clinical follow-up study. Spine. 2005;30(19):2138-2144. *Demonstrated equivalent fusion rates allograft with plating (95%) versus autograft (98%) with no donor site morbidity - shifted practice toward allograft as contemporary standard.* 8. Basques BA, Anandasivam NS, Webb ML, et al. Risk factors for blood transfusion with primary posterior lumbar fusion. Spine. 2015;40(18):1792-1797. *Identified obesity, multilevel surgery, operative time greater than 3 hours as transfusion risk factors - informs preoperative optimization and blood conservation strategies.* 9. Shin DA, Yi S, Yoon DH, Kim KN, Shin HC. Artificial disc replacement combined with fusion versus two-level fusion in cervical two-level disc disease. Spine. 2014;39(15):1233-1239. *Hybrid constructs (arthroplasty + fusion) for two-level disease showed superior ROM preservation and similar clinical outcomes versus two-level ACDF - emerging alternative to consider.* 10. Australian Orthopaedic Association National Joint Replacement Registry. Hip, Knee & Shoulder Arthroplasty: 2023 Annual Report. Adelaide: AOA; 2023. *Australian registry data showing 15,000 ACDF procedures annually, infection rate 0.8%, reoperation 3.2% at 2 years - benchmark outcomes for Australian practice.*

Cervical Spinal Fusion (ACDF)

Cervical Spinal Fusion (ACDF)