Major spine surgery

12 min read Last updated April 8, 2026

Surgical approach

  • Procedures included: multilevel decompression (laminectomy), instrumented fusion (pedicle screws/rods), deformity correction (scoliosis/kyphosis), vertebral column resection, tumour resection, revision surgery
  • Approaches
    • Posterior (most common): midline incision, muscle dissection, decompression, instrumentation, bone grafting; may involve osteotomies (Smith-Petersen, pedicle subtraction, vertebral column resection)
    • Anterior: thoracotomy/thoracoscopy (thoracic), retroperitoneal (lumbar), discectomy/corpectomy and cage/plate; often combined with posterior fixation
    • Combined/staged: anterior + posterior in one sitting or staged days apart (higher physiological insult)
  • Positioning
    • Prone on frame (Jackson/Relton-Hall): abdomen free to reduce venous bleeding; head supported (Mayfield pins for cervical/complex cases)
    • Lateral decubitus for some thoracic/lumbar anterior approaches; supine for cervical anterior discectomy/fusion (less often classed as 'major')
  • Intraoperative adjuncts
    • Neuromonitoring: SSEPs ± MEPs ± EMG; wake-up test rarely used now but may be discussed
    • Cell salvage; tranexamic acid; navigation/robotics; fluoroscopy/CT

Anaesthetic management (headline)

  • Type of anaesthesia: General anaesthesia with controlled ventilation; TIVA often preferred when MEPs used (propofol/remifentanil)
  • Airway: cuffed endotracheal tube (reinforced ETT often helpful); secure well for prone; consider awake fibreoptic/video-assisted intubation if cervical instability/myelopathy/RA/limited neck movement
  • Duration: commonly 4–10+ hours (deformity correction/revision may exceed this); anticipate prolonged prone time and large fluid shifts
  • Pain: severe (multilevel fusion/osteotomies); plan multimodal analgesia ± regional/neuraxial techniques where appropriate
  • Key aims: maintain spinal cord perfusion, minimise blood loss, facilitate neuromonitoring, protect eyes/pressure areas, safe prone positioning, early neuro assessment post-op

Preoperative assessment

  • Indication and neurological baseline: radiculopathy vs myelopathy; document motor/sensory deficits, sphincter symptoms; establish baseline for post-op comparison
  • Comorbidities: cardiac (ischaemia, valvular), respiratory (restrictive disease in scoliosis, OSA), renal, diabetes, frailty; assess exercise tolerance and functional status
  • Scoliosis-specific physiology
    • Restrictive ventilatory defect: reduced FVC/TLC; V/Q mismatch; pulmonary hypertension/cor pulmonale in severe disease
    • Cardiac: RV strain; consider echo if severe curvature, symptoms, or suspected pulmonary HTN
  • Airway and cervical spine: instability, limited movement, prior surgery, halo/traction; plan intubation strategy and discuss with surgeons if need for neuromonitoring baseline before paralysis
  • Haematology and blood planning: baseline Hb, coagulation; group & screen vs crossmatch; anticipate major haemorrhage (revision, deformity correction, tumour, long-segment fusion)
  • Medication review: anticoagulants/antiplatelets (neuraxial implications), chronic opioids, gabapentinoids, steroids (stress dose), ACEi/ARB (hypotension risk), DM meds
  • Consent/discussion: blood products, cell salvage, post-op ICU/HDU, potential for delayed extubation, risk of visual loss/pressure injuries, awareness of neuromonitoring constraints

Monitoring and access

  • Standard monitoring + temperature (forced-air warming, fluid warmers), urinary catheter (hourly output), neuromuscular monitoring (especially if MEPs planned)
  • Arterial line: recommended for major cases (beat-to-beat BP, blood sampling, controlled hypotension if used)
  • Venous access: 2 large-bore cannulae; consider central line if poor access, vasoactive infusions, anticipated massive transfusion, or long case
  • Advanced monitoring: consider cardiac output monitoring in high-risk patients/major blood loss; consider cerebral oximetry in selected high-risk prone cases (local practice dependent)
  • Blood management: cell salvage; point-of-care coagulation (TEG/ROTEM) where available; calcium monitoring during massive transfusion

Induction and maintenance (including neuromonitoring considerations)

  • Induction: standard IV induction; haemodynamic stability important (spinal cord perfusion). Consider gentle induction in patients with limited reserve or severe myelopathy
  • Airway: secure ETT, bite block if MEPs (jaw clenching risk). Ensure robust fixation for prone and long duration
  • Anaesthetic technique with neuromonitoring
    • MEPs: sensitive to volatile agents and neuromuscular blockade; prefer TIVA (propofol + remifentanil). Avoid or minimise volatile (often <0.5 MAC if used) and avoid continuous NMB (may use short-acting for intubation then allow to wear off)
    • SSEPs: less sensitive than MEPs but still depressed by volatiles and hypotension; maintain stable anaesthetic depth and physiology
    • Communicate: anaesthetic changes, BP changes, temperature, Hb, and NMB status can all alter signals
  • Ventilation: lung-protective strategy; avoid high airway pressures (venous bleeding). Maintain normocapnia; consider mild hyperventilation only if specifically indicated and agreed (can reduce spinal cord perfusion)
  • Haemodynamic targets: maintain MAP to support cord perfusion (often MAP ≥ 70–80 mmHg; higher if myelopathy/cord compromise or neuromonitoring changes). Avoid prolonged hypotension
  • Controlled hypotension: may reduce blood loss but risks cord/optic nerve perfusion; only in selected patients with clear targets, short duration, and close neuromonitoring

Positioning (prone) and protection

  • Team brief before turning: airway security, lines, eyes, pressure points, neuromonitoring leads, plan for emergency supination
  • Head/eyes: neutral alignment; avoid direct ocular pressure; check eyes after positioning and intermittently; consider Mayfield pins for stability (pin-site bleeding/air embolism rare)
  • Abdomen free: reduces IVC compression, epidural venous engorgement and bleeding; improves ventilation
  • Arms: brachial plexus protection (abduction < 90°, neutral forearm, padding); avoid ulnar nerve pressure
  • Pressure areas: chest, iliac crests, knees, genitalia; document checks; consider DVT prophylaxis strategy (mechanical intra-op)
  • Endotracheal tube: re-check depth and bilateral air entry after turning prone; beware mainstem intubation with head movement

Blood loss and coagulation management

  • Why bleeding is significant: extensive muscle dissection, cancellous bone bleeding, epidural venous plexus, long duration, revision surgery, osteotomies, tumour vascularity
  • Antifibrinolytic: tranexamic acid commonly used (bolus + infusion; local protocols vary). Consider contraindications (recent thrombosis, seizure risk at high doses, renal impairment dose adjustment)
  • Cell salvage: recommended in major cases; consider contamination issues (infection/tumour—often still used with filters per local policy)
  • Transfusion strategy: anticipate dilutional coagulopathy; use major haemorrhage protocol early if needed; use point-of-care coagulation to guide fibrinogen/platelets/FFP; give calcium to maintain ionised Ca2+
  • Permissive anaemia vs oxygen delivery: balance blood conservation with spinal cord/organ perfusion; consider higher Hb targets in significant cardiorespiratory disease or ongoing neuromonitoring concerns

Fluids, temperature, and metabolic issues

  • Fluids: balanced crystalloids; avoid excessive crystalloid (tissue oedema, airway swelling, impaired wound healing). Use vasopressors early if appropriate rather than fluid overload
  • Colloid/blood: use guided by haemodynamics and blood loss; monitor acid-base, lactate, electrolytes
  • Temperature: high risk of hypothermia (large exposure, long duration) → coagulopathy and wound infection; active warming throughout
  • Glucose: maintain reasonable control; avoid hypoglycaemia; steroids may raise glucose

Analgesia

  • Multimodal: paracetamol + NSAID (if acceptable) + opioid (PCA) ± ketamine infusion (opioid-tolerant) ± lidocaine infusion (local policy) ± gabapentinoids (caution sedation/delirium)
  • Regional/neuraxial options (case-dependent)
    • Intrathecal morphine (single-shot) may provide excellent analgesia but consider respiratory depression risk, pruritus, urinary retention; caution if OSA, prolonged surgery, or planned early neuro assessment
    • Epidural analgesia: often impractical in extensive posterior instrumentation; may mask new neurological deficit; anticoagulation considerations
    • Local infiltration/erector spinae plane blocks: can reduce opioid requirements; evidence evolving; ensure does not interfere with neuromonitoring or surgical field

Emergence and postoperative care

  • Extubation vs ventilation: extubate if normothermic, stable, acceptable blood loss, good gas exchange, minimal airway oedema, and reliable neuro exam possible. Consider elective ventilation after massive transfusion, prolonged prone time, severe OSA/restrictive disease, or airway swelling
  • Immediate neuro assessment: aim for awake, cooperative patient where safe; document motor power; ensure analgesia does not preclude assessment
  • Post-op destination: HDU/ICU for major deformity correction, significant comorbidity, major blood loss, vasopressor requirement, or planned ventilation
  • PONV prophylaxis: high risk (opioids, long surgery); multimodal antiemetics
  • Thromboprophylaxis: mechanical early; chemical prophylaxis timing coordinated with surgeons due to bleeding/epidural haematoma risk

Complications (anaesthetic relevance)

  • Neurological injury: cord ischaemia/compression; risk increased with hypotension, anaemia, major deformity correction; respond to neuromonitoring changes promptly
  • Postoperative visual loss (POVL): ischaemic optic neuropathy/central retinal artery occlusion; risk factors include prolonged prone surgery, major blood loss, hypotension, anaemia, large fluid volumes, male sex, obesity. Prevention: avoid ocular pressure, maintain perfusion, minimise anaemia/hypotension, careful fluid strategy
  • Airway oedema: prolonged prone, large fluids; consider cuff leak test and head-up positioning; delayed extubation if concern
  • Venous air embolism: rare but possible (especially with Mayfield pins, sitting position—less common in major spine now). Signs: sudden ETCO2 drop, hypotension, mill-wheel murmur. Manage: flood field, aspirate via CVC if present, 100% O2, hemodynamic support
  • Massive haemorrhage: hypocalcaemia, coagulopathy, hypothermia, acidosis; use MHP and point-of-care guidance
  • Pressure injuries and neuropathies: ulnar neuropathy, brachial plexus, lateral femoral cutaneous nerve; rhabdomyolysis in prolonged prone/obesity
  • Respiratory complications: atelectasis, pneumonia; higher risk in scoliosis/restrictive disease and OSA; consider NIV/physio early
You are anaesthetising a patient for posterior scoliosis correction with MEP/SSEP monitoring. How will you conduct the anaesthetic?

Structure: goals → technique → monitoring → positioning → blood conservation → response plan.

  • Goals: maintain spinal cord perfusion, stable physiology for monitoring, minimise blood loss, safe prone positioning, effective analgesia and early neuro exam
  • Technique: GA with ETT; prefer TIVA (propofol + remifentanil). Avoid volatile or keep very low; avoid continuous neuromuscular blockade (allow intubating dose to wear off; monitor TOF)
  • Monitoring/access: A-line, 2 large-bore IVs, temperature, urinary catheter, neuromuscular monitor; consider CVC/CO monitoring if high risk
  • Positioning: prone on frame with abdomen free; protect eyes/pressure points; secure ETT and re-check after turning; bite block for MEPs
  • Blood conservation: TXA, cell salvage, normothermia, avoid excessive venous pressure (ventilation/positioning), early MHP if needed, TEG/ROTEM if available
  • Haemodynamics: maintain MAP (often ≥70–80 mmHg; higher if signals change). Use vasopressors rather than fluid overload; avoid prolonged hypotension
  • Analgesia: multimodal + PCA opioid; consider ketamine infusion; consider intrathecal morphine only if appropriate and with respiratory monitoring plan
During deformity correction the neurophysiologist reports sudden loss of MEPs. What is your immediate management?

Treat as spinal cord ischaemia/compression until proven otherwise; act rapidly and communicate.

  • Call out and stop surgical manipulation; ask surgeon to release correction/traction and check hardware/cord compression
  • Optimise perfusion: increase MAP promptly (vasopressors/fluids as appropriate); aim higher than baseline; correct hypotension immediately
  • Check anaesthetic factors: ensure no recent bolus of propofol/volatile increase; confirm no residual/added neuromuscular blockade; check TOF
  • Correct physiology: ensure adequate oxygenation/ventilation, normocapnia, normothermia; check Hb and correct significant anaemia; treat hypocalcaemia/acidosis if massive transfusion
  • Technical checks: leads/electrodes, stimulation settings, artefact; confirm with SSEPs/other modalities
  • If unresolved: consider wake-up test if feasible; consider imaging/re-exploration; document timeline and actions
Discuss the causes, prevention and management of postoperative visual loss after prone spine surgery.

Common FRCA viva topic: recognise risk factors and prevention strategies.

  • Causes: ischaemic optic neuropathy (anterior/posterior), central retinal artery occlusion (often from direct ocular pressure), cortical blindness (rare)
  • Risk factors: prolonged prone surgery, major blood loss, hypotension, anaemia, large fluid volumes, obesity, male sex; direct eye pressure particularly for CRAO
  • Prevention: meticulous head/eye positioning with no ocular pressure; frequent eye checks; maintain MAP/oxygen delivery; avoid prolonged severe hypotension; minimise haemodilution and excessive crystalloids; consider staging very long cases
  • Management: urgent recognition; immediate ophthalmology review; check for external eye pressure/injury; optimise haemodynamics and oxygenation; document and inform patient; incident reporting
How does scoliosis affect respiratory and cardiovascular physiology and what are the anaesthetic implications?
  • Respiratory: restrictive defect (↓FVC/TLC), reduced chest wall compliance, V/Q mismatch; severe disease may cause pulmonary hypertension and cor pulmonale
  • Cardiac: RV strain; consider echo if symptomatic/severe; increased perioperative risk with severe pulmonary HTN
  • Implications: careful pre-op assessment (PFTs/ABG/echo as indicated), lung-protective ventilation, cautious extubation planning, consider post-op HDU/ICU and NIV
Outline a blood conservation strategy for major spine surgery.
  • Pre-op: optimise Hb (iron/ESA if time), stop/bridge anticoagulants appropriately, plan crossmatch and MHP availability
  • Intra-op pharmacology: tranexamic acid per protocol; consider topical haemostats (surgical)
  • Techniques: cell salvage; meticulous positioning (abdomen free) to reduce venous bleeding; maintain normothermia; avoid excessive airway pressures/PEEP if increasing venous bleeding
  • Transfusion/coagulation: early recognition of major haemorrhage; use TEG/ROTEM; replace fibrinogen early if low; give calcium; avoid dilutional coagulopathy
What are the anaesthetic hazards of the prone position and how do you mitigate them?
  • Airway: ETT displacement/obstruction; mitigate with secure fixation, re-check after turning, accessible circuit, plan for emergency supination
  • Eyes: corneal abrasion/POVL/CRAO from pressure; mitigate with careful head support, no ocular pressure, regular checks, maintain perfusion
  • Nerves/pressure: brachial plexus, ulnar nerve, pressure sores; mitigate with padding, arm abduction <90°, neutral alignment, periodic checks
  • Haemodynamics/ventilation: IVC compression increases bleeding and reduces venous return; mitigate with abdomen free and appropriate frame
How do volatile agents and neuromuscular blockers affect SSEPs and MEPs?
  • Volatile agents: dose-dependent depression of SSEP amplitude and increased latency; marked suppression of MEPs even at low MAC
  • Neuromuscular blockers: minimal effect on SSEPs; abolish or markedly reduce MEPs and EMG responses—avoid continuous paralysis when MEPs required
  • Practical: TIVA preferred; if volatile used keep low and stable; use TOF monitoring and communicate any drug changes to neurophysiology
A patient is bleeding heavily during posterior fusion. What are your priorities in the first 10 minutes?
  • Call for help and activate major haemorrhage protocol early; inform blood bank; ensure rapid infuser/warmers available
  • Resuscitate: 100% O2, secure airway/ventilation, maintain MAP with vasopressors and blood products; obtain large-bore access if not already
  • Send/perform labs: ABG, Hb, coagulation, fibrinogen, calcium; use TEG/ROTEM if available
  • Give TXA if not already; start cell salvage; maintain normothermia
  • Coordinate with surgeons: request temporary packing, haemostasis, consider staging/abandoning if unsafe; document events
Describe your anaesthetic management for a patient undergoing major posterior spinal fusion in the prone position.

Use an A–E structure: assessment, preparation, conduct, complications, post-op.

  • Assessment: comorbidities (restrictive lung disease/OSA), airway/cervical spine, neuro baseline, blood loss risk, meds (anticoagulants/opioids)
  • Preparation: A-line, large-bore IV, blood products/cell salvage/TXA, warming, plan for neuromonitoring (TIVA, minimal NMB), positioning checklist
  • Conduct: GA with ETT; controlled ventilation; MAP targets; fluid and transfusion strategy; temperature control; frequent checks of eyes/pressure points
  • Complications: massive haemorrhage, neuromonitoring changes/cord ischaemia, POVL, airway oedema, VAE, pressure neuropathies
  • Post-op: extubation decision, analgesia plan, neuro exam, HDU/ICU, thromboprophylaxis timing
Discuss intraoperative neurophysiological monitoring during spine surgery: indications, anaesthetic implications, and troubleshooting.
  • Indications: deformity correction, intramedullary/extradural tumour, high-risk decompression, revision surgery, instrumentation near cord/roots
  • Modalities: SSEPs (dorsal column), MEPs (corticospinal), EMG (nerve root irritation), D-waves (specialist)
  • Anaesthetic implications: TIVA preferred; avoid continuous NMB for MEPs; maintain stable MAP, temperature, oxygenation, CO2, Hb; avoid sudden changes in anaesthetic depth
  • Troubleshooting: check technical factors, drugs (volatile/NMB), physiology (MAP/Hb/temp/CO2), surgical events (traction/compression); escalate and consider wake-up test
What are the causes of major haemorrhage in spine surgery and how would you manage it?
  • Causes: epidural venous plexus bleeding, cancellous bone, osteotomies, tumour vascularity, revision surgery, coagulopathy/hypothermia, raised venous pressure (abdominal compression/high airway pressures)
  • Management: MHP, balanced resuscitation, point-of-care guided coagulation (fibrinogen/platelets), calcium replacement, warming, TXA, cell salvage, surgical haemostasis/packing, maintain MAP for cord perfusion
Describe the anaesthetic considerations for prone positioning, including prevention of pressure-related injuries and postoperative visual loss.
  • Prone hazards: airway displacement, ocular pressure/POVL, nerve injuries, pressure sores, abdominal compression (bleeding/ventilation), venous pooling, access limitations
  • Prevention: structured turning checklist; secure ETT/lines; head neutral with no eye pressure; abdomen free; arms <90° abduction; padding; regular checks; maintain perfusion and normothermia

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