The anterior approach to the cervical spine (Robinson-Smith/Cloward) provides access to C3-T1 vertebral bodies for ACDF, corpectomy, and fusion procedures. The approach develops the interval between carotid sheath (lateral) and tracheoesophageal complex (medial). Left-sided approach is preferred because the recurrent laryngeal nerve has a longer, more lateral course on the left (ascending from aortic arch), making it less prone to traction injury during tracheoesophageal retraction—right-sided approaches have 2-3x higher RLN injury risk. Key structures at risk: recurrent laryngeal nerve (1-5% injury, causes hoarseness), sympathetic chain on longus colli (Horner syndrome from lateral monopolar cautery), superior and inferior thyroid vessels, and C5 nerve root (1-10% palsy, cord shift mechanism). Release retractors every 30 minutes to reduce nerve ischaemia.

Absolute Indications

• Cervical radiculopathy: Failed 6-12 weeks conservative management with MRI-confirmed nerve root compression correlating with clinical findings [11]
• Cervical myelopathy: Progressive or moderate-to-severe symptoms with cord compression on MRI, especially with cord signal changes [12]
• Unstable cervical fractures: Burst fractures, teardrop fractures, facet dislocations with disc herniation requiring anterior decompression and stabilization [13]
• Infection: Discitis/osteomyelitis requiring debridement, particularly with epidural abscess formation [14]

Relative Indications

• Axial neck pain: Isolated cervical spondylosis without radiculopathy/myelopathy - controversial, outcomes less predictable than radiculopathy [15]
• OPLL: Ossification posterior longitudinal ligament causing stenosis - anterior approach if OPLL less than 50% canal occupation and not ossification mass effect [16]
• Pseudoarthrosis: Failed posterior fusion requiring anterior revision and interbody support
• Tumor: Primary vertebral body tumor or metastatic disease requiring corpectomy and reconstruction

Contraindications

Absolute:

• Active infection overlying surgical site (not for septic indication)
• Severe cervical kyphotic deformity (greater than 40 degrees) requiring posterior approach for alignment correction
• Ankylosing spondylitis with fused spine (risk of catastrophic three-column fracture with anterior opening)

Relative:

• Previous anterior neck surgery (increased adhesions, prior radiation increases complication risk)
• Severe OPLL (greater than 60% canal occupation or ossification mass) - posterior decompression safer
• Tracheostomy present (contamination risk, technical difficulty)
• Morbid obesity (increases retraction difficulty, visualization challenges)
• Short/thick neck anatomy (limited C7-T1 access, may require sternotomy)
• Carotid artery stenosis (manipulation risk, consider vascular surgery consultation)

Clinical Assessment

• Neurological examination: Document baseline motor strength (myotomal), sensation (dermatomal), reflexes, Hoffmann sign, clonus, gait (if myelopathy suspected)
• Identify level clinically: Correlate symptoms with imaging (C5-6 disc affects C6 nerve root causing biceps weakness; C6-7 affects C7 causing triceps weakness)
• Voice assessment: Document pre-operative hoarseness (if present, may influence side selection or require ENT evaluation)
• Swallowing assessment: Pre-existing dysphagia noted (ACDF can worsen transiently)
• Medical optimization: Smoking cessation (improves fusion rates from 60-70% to 90-95%), diabetic control (HbA1c less than 7%), anticoagulation management (hold warfarin 5 days pre-op, bridging protocol for high-risk patients)

Imaging Review

MRI Cervical Spine:

• Sagittal T2: Disc herniation, cord compression, cord signal changes (T2 hyperintensity = myelomalacia, poor prognosis)
• Axial T2: Lateral vs central herniation, foraminal stenosis
• Assess all levels (multi-level disease common - may influence surgical planning)

CT Cervical Spine:

• Bone quality assessment (osteoporosis influences implant choice)
• Posterior osteophyte size (helps predict decompression extent needed)
• OPLL evaluation (thickness, levels involved, presence of dural ossification)
• Fracture pattern if trauma (assess posterior column integrity)

Plain Radiographs:

• Standing lateral and AP views
• Flexion-extension laterals: Assess instability (greater than 3.5mm translation or 11 degrees angulation at one level abnormal, indicates need for instrumentation)
• Assess global cervical alignment (lordosis, C2-C7 plumb line)

Special Studies:

• CT angiography: If revision surgery, aberrant anatomy suspected, or older patient (vertebral artery anomaly screening)
• Dynamic flexion-extension MRI: If suspecting instability but plain films equivocal
• EMG/NCS: If diagnosis unclear or multiple potential levels (helps localize pathology)

Consent Discussion

Expected Outcomes:

• Radiculopathy: 90-95% significant improvement in arm pain, 80-85% return to pre-symptom function [11]
• Myelopathy: Halts progression in 80-90%, functional improvement in 50-70% (depends on severity and duration - chronic severe myelopathy has limited recovery potential) [12]
• Fusion rate: 95-98% single level, 90-95% two level, 85-90% three or more levels [17]
• Return to work: Light duty 4-6 weeks, full duty 8-12 weeks

Risks:

General (all surgery):

• Infection: Superficial 1-2%, deep 0.5-1% [18]
• Blood loss requiring transfusion: Less than 1%
• VTE: Less than 1% with prophylaxis

Specific to anterior cervical approach:

• Recurrent laryngeal nerve injury (1-5%): Temporary hoarseness most common (90% resolve by 6 months), permanent hoarseness less than 1% [19]
• Dysphagia (10-50% transient, 5-10% at 1 year): More common in women, multi-level surgery, revision cases [20]
• C5 nerve root palsy (1-10%): Deltoid/biceps weakness, typically neuropraxic and recovers in 6-12 months
• Esophageal injury (less than 0.5%): Rare but serious, can lead to mediastinitis if not recognized
• Vertebral artery injury (less than 0.5%): Typically with lateral dissection beyond 17mm from midline
• Horner syndrome (less than 0.5%): Sympathetic chain injury, usually temporary
• Dural tear/CSF leak (1-3%): Higher with OPLL, revision surgery
• Pseudoarthrosis (5-10%): Higher in smokers, multi-level fusions, stand-alone cages without plates

Long-term:

• Adjacent segment disease (2-3% per year): Degeneration at levels above/below fusion, may require revision (25% at 10 years)
• Hardware issues: Plate prominence (5-10%), screw loosening (5%), dysphagia from hardware
• Persistent symptoms: 10-20% continue to have neck pain despite solid fusion

Alternatives:

• Conservative management (physiotherapy, medications, epidural injections)
• Posterior cervical foraminotomy (for lateral soft disc without instability)
• Cervical disc arthroplasty (for appropriate candidates - single level, no facet arthropathy, age less than 60)
• Posterior laminectomy/laminoplasty (for multi-level stenosis without kyphosis)

Implants

• ACDF: Interbody spacer (PEEK cage, allograft, autograft), anterior cervical plate (variable angle screws), screws (typically 14-16mm length for vertebral body purchase)
• Corpectomy: Expandable cage or fibular strut allograft, longer plate spanning corpectomy
• Sizing: Have multiple cage heights available (5mm, 6mm, 7mm typical range), trial before final implant

Instruments

• Standard anterior cervical spine set
• High-speed burr for discectomy/corpectomy
• Caspar distraction pins (for interspace distraction during discectomy)
• Curettes (straight and angled for disc removal)
• Kerrison rongeurs (for posterior osteophyte/PLL removal)
• Depth gauge (for screw length measurement)
• Handheld retractors (Army-Navy, Richardson)
• Self-retaining retractors (Cloward, Caspar variant with blade sets)

Adjuncts

• Image intensifier: Lateral fluoroscopy essential for level localization, assessment of decompression, hardware positioning
• Microscope or loupes: For decompression (especially OPLL or revision cases)
• Intraoperative neuromonitoring: SSEPs and MEPs recommended for myelopathy cases (alerts to cord injury) [21]
• Radiolucent table: Carbon fiber OR table for imaging
• Gardner-Wells tongs (optional): For intraoperative traction to open disc space

Fascial Layers (Superficial to Deep)

1. Skin and subcutaneous tissue: Includes platysma muscle
2. Superficial cervical fascia: Investing layer encloses SCM and trapezius
3. Deep cervical fascia:
   • Superficial layer (investing): Encloses SCM, omohyoid
   • Middle layer (pretracheal): Encloses thyroid gland, trachea, esophagus
   • Deep layer (prevertebral): Covers longus colli muscles and anterior vertebral bodies - THIS is incised to access spine
4. Longus colli muscles: Bilateral muscles on anterior vertebral bodies - retracted laterally to expose midline

Key Anatomical Relationships

Sternocleidomastoid Muscle (SCM):

• Origins: Sternal head from manubrium, clavicular head from medial clavicle
• Insertion: Mastoid process
• Innervation: CN XI (spinal accessory nerve)
• Surgical relevance: Medial border of SCM is key landmark - incision medial to SCM, SCM retracted laterally

Carotid Sheath:

• Contains: Common carotid artery (medial), internal jugular vein (lateral), vagus nerve (posterior between artery and vein)
• Surgical relevance: Retracted laterally after identification, palpate carotid pulse throughout procedure

Tracheoesophageal Complex:

• Trachea (anterior), esophagus (posterior), thyroid gland (anterior, C5-T1 levels)
• Surgical relevance: Retracted medially, gentle retraction to avoid recurrent laryngeal nerve injury

Recurrent Laryngeal Nerve:

• Right side: Branches from vagus at subclavian artery level, loops under artery, ascends obliquely in tracheoesophageal groove
• Left side: Branches from vagus at aortic arch level (in chest), ascends more vertically in tracheoesophageal groove
• Surgical relevance: DOES NOT need to be directly identified (runs in tracheoesophageal groove - protected by gentle medial retraction of complex). Direct dissection looking for nerve increases injury risk.
• Level variation: At C6-C7, nerve in groove; at C2-C3, nerve branches to larynx (external branch of superior laryngeal nerve crosses field from lateral to medial - injury causes voice fatigue)

Superior Thyroid Artery:

• Branch of external carotid artery
• Crosses field at C4-C5 level laterally
• Surgical relevance: May require ligation for multi-level exposure C3-C6

Inferior Thyroid Artery:

• Branch of thyrocervical trunk (from subclavian artery)
• Crosses field at C6-C7 level laterally
• Surgical relevance: Recurrent laryngeal nerve has intimate relationship with artery (nerve posterior to artery on right, variable on left). Ligation sometimes needed for low cervical access, but increases RLN injury risk - ligate only if absolutely necessary.

Sympathetic Chain:

• Lies on longus colli muscle, lateral to midline, medial to carotid sheath
• Cervical ganglia: Superior (C2-C3), middle (C6), inferior/stellate (C7-T1)
• Surgical relevance: Monopolar cautery lateral to midline on longus colli can cause thermal injury → Horner syndrome (ptosis, miosis, anhidrosis). Use bipolar cautery, stay midline.

Vertebral Artery:

• Enters foramen transversarium typically at C6 level
• Ascends through transverse processes C6-C2
• Emerges from C2, loops posteriorly to enter foramen magnum
• Surgical relevance: Safe zone is 17mm lateral from midline - dissection lateral to uncinate process (uncovertebral joint) risks vertebral artery injury. Aberrant anatomy (artery enters at C4 or C5) occurs in 5-10%.

Thoracic Duct:

• Ascends on left side of esophagus, arches laterally at C7-T1, drains into junction of left subclavian and internal jugular veins
• Surgical relevance: Left-sided C7-T1 approaches risk thoracic duct injury (chylothorax if injured). Some surgeons prefer right-sided approach at C7-T1 to avoid duct, but must balance against increased RLN risk.

The anterior approach to the cervical spine utilizes an avascular internervous plane between the carotid sheath laterally (containing carotid artery, internal jugular vein, vagus nerve) and the tracheoesophageal complex medially (containing trachea, esophagus, and recurrent laryngeal nerve in the tracheoesophageal groove).

Key anatomical points:

• The plane is developed by blunt finger dissection after incising the deep cervical fascia along the medial border of SCM
• The carotid pulse is palpated and retracted laterally with the carotid sheath
• The trachea and esophagus are retracted medially as a unit
• This plane is truly internervous as structures on either side have different nerve supplies
• Lateral: carotid sheath contents supplied by CN IX, X, XI, sympathetic chain
• Medial: tracheoesophageal complex supplied by recurrent laryngeal nerve (CN X) and external laryngeal nerve

Danger zones:

• Stay within 15-17mm of midline laterally to avoid vertebral artery at uncinate processes
• The sympathetic chain lies on the lateral aspect of longus colli - monopolar cautery lateral to midline risks Horner syndrome
• Recurrent laryngeal nerve in tracheoesophageal groove - gentle medial retraction only

Standard Position

• Supine: Patient flat on radiolucent table
• Head: Head ring (donut) or horseshoe headrest, neutral to slight extension (10-15 degrees)
  • Avoid excessive extension (narrows spinal canal, risks cord injury in myelopathy patients)
  • Padding under occiput to prevent pressure sore
• Shoulders: Tape shoulders caudally (improves C6-T1 visualization on lateral fluoroscopy)
  • Tape from acromion angled caudally toward foot of bed, secure to table
  • Check lateral fluoro after taping - should see bottom of C7 vertebral body
• Shoulder roll: Rolled towel/bolster under shoulders at level of scapulae/T1-T2 to extend neck
• Arms: Tucked at sides, padded, secured with draw sheet
• Lower extremities: Padded, neutral position, sequential compression devices applied

Key Positioning Points

1. Neck extension: Opens anterior disc space, flattens cervical lordosis for access
2. Shoulder taping: Essential for lower cervical levels (C6-T1) to clear shoulders from fluoro
3. Avoid hyperextension: Can worsen myelopathy by narrowing spinal canal
4. Confirm visualization: Check lateral fluoroscopy after positioning - adjust if levels not visible

Anaesthesia

• General anaesthesia with endotracheal intubation: Standard
• Intubation considerations:
  • Small endotracheal tube (6.0-7.0mm) reduces tracheal pressure and dysphagia risk
  • Avoid nasogastric tube (NGT) - increases dysphagia, esophageal injury risk
  • Record which side tube cuff inflated (may influence side selection if difficult airway)
• Muscle relaxation: Complete paralysis for neuromonitoring (if MEPs used, discuss with anaesthesia regarding timing of relaxant doses)
• Antibiotics: Cefazolin 2g IV (or vancomycin 15mg/kg if MRSA risk/allergy) within 60 minutes of incision

Positioning

• Supine: Patient flat on radiolucent table
• Head: Head ring (donut) or horseshoe headrest, neutral to slight extension (10-15 degrees)
  • Avoid excessive extension (narrows spinal canal, risks cord injury in myelopathy patients)
  • Padding under occiput to prevent pressure sore
• Shoulders: Tape shoulders caudally (improves C6-T1 visualization on lateral fluoroscopy)
  • Tape from acromion angled caudally toward foot of bed, secure to table
  • Check lateral fluoro after taping - should see bottom of C7 vertebral body
• Shoulder roll: Rolled towel/bolster under shoulders to extend neck and flatten cervical spine
  • Improves anterior access to vertebral bodies
  • Position at level of scapulae/T1-T2 region
• Arms: Tucked at sides, padded, secured with draw sheet
• Lower extremities: Padded, neutral position, sequential compression devices applied

Preparation

• Hair removal: None typically needed (if beard impedes operative field, clipper trim only - no shave to reduce infection risk)
• Skin prep: Chlorhexidine-alcohol from mandible to nipples, laterally to table bilaterally (wide prep for potential sternotomy if needed for low levels)
• Draping: Head draped out of field superiorly, impervious drapes, expose neck from mandible to sternal notch
• Oral prep: Some surgeons swish chlorhexidine mouthwash pre-drape (reduce oral flora contamination risk)

Level Localization

1. Palpate landmarks BEFORE draping:
   • Hyoid bone (C3 level)
   • Thyroid cartilage (C4-C5 level)
   • Cricoid cartilage (C6 level - most reliable landmark)
   • Carotid tubercle of C6 (anterior tubercle of transverse process - palpable laterally at C6 level)
2. Mark skin incision based on target level and landmark
3. Intraoperative fluoroscopy:
   • Lateral C-arm view
   • 22G spinal needle in disc space (confirms level - COUNT from C2 or T1 to ensure correct)
   • All levels anterior to C7 visible without shoulder taping typically
   • C7-T1 requires shoulder taping or retraction

Immediate (Recovery Room)

• Airway monitoring: CRITICAL - hematoma can expand and compromise airway
  • Monitor for stridor, dyspnea, neck swelling
  • If concern → immediate bedside drain removal and wound opening (do NOT wait for OR)
• Neurovascular check: Document motor/sensory in all extremities (compare to pre-op baseline)
• Voice check: Ask patient to speak - hoarseness expected but document
• Drain output: Monitor if drain placed (should be minimal, less than 50mL in first few hours)
• X-ray: Lateral cervical spine (confirm hardware position, alignment, no hematoma causing tracheal deviation)

Inpatient (Days 0-1)

• Mobilize: Out of bed day of surgery or POD1 (no movement restrictions needed for stable construct)
• Diet: Start clear liquids evening of surgery if no dysphagia, advance as tolerated
  • Dysphagia common first 24-48 hours (improves with time)
  • Soft diet or liquids for first few days if dysphagia prominent
• Pain management: Multimodal (acetaminophen, muscle relaxants, opioids as needed)
  • Avoid NSAIDs (theoretical fusion inhibition concern - controversial)
• Drain removal: POD1 if output less than 30mL in 8 hours
• Collar: Soft collar for comfort (NOT for immobilization) - most surgeons do not routinely use

Discharge Criteria

• Pain controlled on oral medications
• Tolerating diet without significant dysphagia
• No airway concerns
• Neurologically stable or improved
• Mobilizing independently
• Understanding of warning signs (dyspnea, stridor, new weakness)

Follow-up

2 Weeks:

• Wound check
• Remove sutures if non-absorbable used
• Assess dysphagia (should be improving)
• Assess voice (hoarseness should be improving - if not, consider ENT referral for laryngoscopy at 4-6 weeks)

6 Weeks:

• Clinical assessment: Pain, function, neurological status
• X-rays: AP and lateral cervical spine (assess alignment, hardware position, early fusion signs)
• Activity: No restrictions typically - resume normal activities as pain allows
• Return to light work if sedentary job

3 Months:

• X-rays: Assess fusion progress (bridging bone across interspaces, no lucency around cage)
• Flexion-extension views: Assess for motion at operated levels (motion suggests pseudoarthrosis)
• If fusing well: Return to full activities including contact sports/heavy labor

6-12 Months:

• Final fusion assessment
• CT scan if X-ray equivocal or pseudoarthrosis suspected
• Discharge if solid fusion and clinically well
• If pseudoarthrosis: Revision surgery if symptomatic

Long-term:

• Annual X-rays for first 5 years (monitor adjacent segment degeneration)
• Re-refer if new radiculopathy or myelopathy symptoms develop

Airway Compromise from Hematoma

Incidence: Less than 1% but potentially fatal [22]

Risk factors: Multi-level surgery, revision cases, anticoagulation, inadequate haemostasis

Recognition:

• Neck swelling, stridor, dyspnea, respiratory distress
• Usually occurs within first 24 hours (most in first 6 hours)

Management:

• IMMEDIATE: This is a surgical emergency
• If early signs (mild swelling, no respiratory distress): Close observation, consider neck CT to assess hematoma size
• If respiratory distress:
  • Call for anaesthesia help immediately
  • Remove dressing and open wound at bedside (remove skin closure, evacuate hematoma)
  • DO NOT delay for OR - airway compromise can occur within minutes
  • Prepare for difficult intubation (edema, hematoma distort anatomy)
  • After airway secured, take to OR for formal washout and haemostasis
• Prevention: Meticulous haemostasis, drain use (controversial), blood pressure control post-op

Recurrent Laryngeal Nerve Injury

Incidence: 1-5% overall, higher right-sided approaches (3-7% vs 1-3% left) [19]

Clinical presentation:

• Unilateral injury: Hoarseness, voice weakness/fatigue, aspiration risk (vocal cord paralysis prevents glottis closure)
• Bilateral injury: RARE but catastrophic - airway obstruction (both cords paramedian position), requires emergency tracheostomy

Risk factors: Right-sided approach, low cervical levels (C6-T1), prolonged retraction, multi-level surgery, revision cases

Recognition:

• Post-operative hoarseness (common and expected to some degree)
• Persistent hoarseness beyond 2 weeks should prompt ENT evaluation
• Laryngoscopy: Vocal cord paralysis (cord in paramedian or lateral position, does not move with phonation)

Management:

• Immediate post-op: Document hoarseness, voice therapy referral
• If persistent at 2-4 weeks: ENT consultation, laryngoscopy to confirm cord position
• Conservative (most cases): Voice therapy, observation - 80-90% neuropraxic injuries recover spontaneously in 6-12 months
• If no recovery by 6 months: Consider medialization procedures (vocal cord injection, thyroplasty)
• Prevention: Left-sided approach preferred, gentle retraction, release retractor every 30 minutes, avoid excessive extension

C5 Nerve Root Palsy

Incidence: 1-10% after ACDF, higher with multi-level decompression and myelopathy [23]

Clinical presentation:

• Deltoid and/or biceps weakness (C5 myotome) appearing 1-3 days post-operatively
• Sensation typically intact or minimally affected
• Reflexes (biceps reflex) may be diminished

Pathophysiology (debated):

• NOT direct nerve injury (nerve not in operative field)
• Likely mechanism: Cord shift posteriorly after anterior decompression → tethered nerve roots stretched (C5 shortest, most horizontal nerve root → most susceptible)
• Alternative theory: Ischemic injury to nerve root from cord reperfusion after decompression

Risk factors: Myelopathy, multi-level decompression, significant cord compression pre-op, excessive distraction during procedure

Management:

• Recognition: Document weakness on post-op exam
• Imaging: MRI if severe or concerns for hematoma (usually shows cord posterior shift, no compressive pathology)
• Treatment: Conservative - most recover spontaneously in 3-12 months (80-90% full recovery)
  • Physiotherapy for shoulder strengthening
  • Sling for comfort if needed (avoid prolonged use - causes stiffness)
  • EMG at 6-8 weeks if not improving (document neuropraxia vs axonotmesis)
  • Reassurance to patient (recovery expected but slow)
• Prevention: Unclear (mechanism not fully understood) - avoid excessive distraction, consider decompression adequacy without over-aggressive technique

Dysphagia

Incidence: 10-50% transient (first month), 5-10% at 1 year [20]

Risk factors: Female sex, multi-level surgery, revision surgery, prolonged retraction, prominent hardware

Clinical presentation:

• Difficulty swallowing solids more than liquids
• Globus sensation (lump in throat)
• Range from mild (requires liquid with meals) to severe (cannot tolerate solids, weight loss)

Management:

• Mild (most cases): Reassurance, soft diet, time (90% improve by 3 months)
• Moderate: Speech pathology referral for swallowing therapy, swallow study if aspiration concern
• Severe or persistent (greater than 6 months): Consider imaging (CT) to assess for hardware prominence, esophageal injury
  • If hardware prominent: May require revision with plate removal or low-profile implant
  • If esophageal stricture: GI consultation for dilation
• Prevention: Gentle retraction of tracheoesophagus, release retractor periodically, low-profile implants, avoid excessive anterior plate prominence

Esophageal Injury

Incidence: Less than 0.5% but serious complication [24]

Risk factors: Revision surgery, severe OPLL, anterior osteophytes, excessive retraction, sharp retractors, long screws penetrating posterior vertebral body

Recognition:

• Intraoperative: Visualization of esophageal mucosa, air leak during ventilation, methylene blue test (inject methylene blue via NGT, observe for leak)
• Post-operative: Dysphagia, odynophagia, fever, subcutaneous emphysema, wound drainage (saliva, purulent material), mediastinitis (late - sepsis, shock)

Management:

• If recognized intraoperatively:
  • Primary repair in two layers (mucosa with absorbable suture, muscle layer with absorbable or permanent)
  • ENT or thoracic surgery consultation for repair
  • NGT placement for feeding (bypass repair for 7-10 days)
  • Broad-spectrum antibiotics (anaerobic coverage)
  • Consider drain placement
  • Remove hardware if contaminated OR leave if feels clean field and repair solid (controversial)
• If recognized post-operatively:
  • NPO immediately
  • Broad-spectrum antibiotics (including anaerobic coverage)
  • CT neck/chest with oral contrast (assess leak extent, abscess formation)
  • ENT/thoracic surgery consultation urgently
  • May require surgical exploration, debridement, repair, hardware removal, feeding jejunostomy
  • If delayed presentation with mediastinitis: High mortality (10-20%), requires aggressive management
• Prevention: Gentle tissue handling, avoid sharp retractors against esophagus, appropriate screw length (14-16mm typical, avoid bicortical purchase), careful multi-level dissection

Vertebral Artery Injury

Incidence: Less than 0.5% [25]

Mechanism: Lateral dissection beyond uncovertebral joints (greater than 17mm from midline), aberrant artery anatomy (enters foramen transversarium at C4 or C5 rather than C6), lateral screw placement

Recognition:

• Intraoperative: Brisk arterial bleeding from lateral dissection or screw hole
• Post-operative: Posterior circulation stroke symptoms (ataxia, vertigo, diplopia, dysphagia, dysarthria)

Management:

• If recognized intraoperatively:
  • Do NOT panic
  • Obtain control: Pack wound with hemostatic agents (Gelfoam, Surgicel), direct pressure
  • Expose proximal and distal control points if possible (difficult)
  • Ligation acceptable if unilateral injury and contralateral vertebral artery patent (90% patients tolerate unilateral VA sacrifice)
  • Vascular surgery consultation for repair vs ligation decision
  • Post-op CT angiography to confirm contralateral VA patency
  • Consider anti-platelet therapy (prevent thrombus propagation)
• If suspected post-operatively:
  • Urgent CT angiography (confirm injury, assess flow in contralateral VA)
  • Neurology consultation
  • Interventional radiology - may require endovascular coiling or stenting
• Prevention: Limit lateral dissection to 15mm from midline, stay medial to uncinate process during decompression, pre-op CT angiography if revision or anomaly suspected

Dural Tear / CSF Leak

Incidence: 1-3%, higher with OPLL (up to 10%), revision cases [26]

Recognition:

• Intraoperative: Clear fluid from surgical field, visible dura defect
• Post-operative: Headache (worse with upright position, improves supine), nausea, wound drainage (clear fluid), pseudomeningocele (fluid collection), meningitis (if communication with skin)

Management:

• Small tear recognized intraoperatively:
  • Attempt primary repair with 6-0 or 7-0 Prolene if accessible
  • If not accessible (posterior tear): Pack with muscle graft or DuraSeal, position patient flat 24-48 hours post-op
  • Drain wound (prevents CSF accumulation under wound → leak)
• Unrecognized tear with post-op leak:
  • Confirm: Beta-2 transferrin test of fluid (specific for CSF)
  • Conservative: Bed rest flat, acetazolamide (reduce CSF production), oversew wound if leaking
  • If conservative fails (leak persists greater than 5-7 days): Surgical repair (re-explore, identify tear, repair or patch)
  • Lumbar drain placement to reduce CSF pressure (controversial - may help healing)
• Prevention: Avoid aggressive PLL removal if not necessary, careful technique with OPLL (dura often adherent or ossified), use Kerrison rongeurs (not pituitary rongeurs) for decompression near dura

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