Positioning injuries

Surgical approach (context: procedures commonly requiring high-risk positioning)

Not an operation itself; injuries arise from surgical positioning and access requirements.
Lithotomy (gynae/urology/colorectal): legs elevated in stirrups; Trendelenburg may be added; perineal access; often long duration.
Steep Trendelenburg (robotic pelvic surgery): head-down tilt, shoulder supports/straps sometimes used; pneumoperitoneum; arms tucked.
Prone (spine/neurosurgery): chest/pelvic bolsters or frame; head in prone pillow/pins; abdomen free if possible; arms abducted or tucked.
Lateral decubitus (thoracotomy/hip): dependent axillary roll; kidney bridge may be raised; flexion at waist; dependent arm supported.
Beach chair (shoulder surgery): semi-sitting; head secured; deliberate hypotension sometimes requested; interscalene block common.

Anaesthetic management (positioning injury focus)

Type of anaesthesia: usually GA (immobility + tolerance of extreme positions); regional often adjunct (e.g., neuraxial for lithotomy; interscalene for shoulder).
Airway: ETT preferred for prone/steep Trendelenburg/robotic and long cases; SGA may be acceptable for short, supine cases with minimal tilt (institution-dependent).
Duration: risk rises with time; high-risk typically >2–4 h (neuropraxia/pressure injury) and very high risk with prolonged lithotomy/Trendelenburg/prone (>4–6 h).
Pain: positioning itself not painful under GA but causes postoperative neuropathic pain/weakness; some positions (prone spine, shoulder) are associated with significant surgical pain—use multimodal analgesia and regional where appropriate.
Core strategy: pre-position check + document; protect pressure points; avoid stretch/compression; maintain perfusion/oxygenation; re-check after draping and periodically.

Definition and classification

Positioning injury = harm due to pressure, stretch, compression, shear, malalignment or impaired perfusion occurring perioperatively.
Types: peripheral nerve injury (PNI), pressure injury/skin necrosis, ocular injury (corneal abrasion, CRAO/ION), musculoskeletal injury, compartment syndrome, rhabdomyolysis, airway/vascular device-related injury, thromboembolism related to immobility.
Mechanisms: compression (between bone and external surface), stretch (excess joint abduction/rotation), ischaemia (hypotension/low flow + pressure), reperfusion injury.

Risk factors

Patient: obesity or very low BMI, diabetes, peripheral neuropathy, smoking, vascular disease, anaemia, hypotension, dehydration, malnutrition, advanced age, pregnancy, connective tissue disease, renal failure.
Surgery/position: prolonged duration, extreme positions (prone, steep Trendelenburg, lithotomy, lateral with kidney bridge), pneumoperitoneum, deliberate hypotension, tourniquet use, robotic surgery (limited access after docking).
Anaesthesia: GA (loss of protective reflexes), muscle relaxation, neuraxial block (loss of pain warning), vasopressors (marker of low flow), hypothermia (vasoconstriction).
Systems: inadequate staffing for positioning, poor equipment (worn padding), time pressure, failure to re-check after draping, poor documentation/communication.

General prevention principles (FRCA core)

Team brief before positioning: intended position, duration, access limitations, pressure points, special risks (eyes, nerves, compartment syndrome), plan for periodic checks.
Neutral alignment: head/neck midline; avoid excessive flexion/extension/rotation; maintain natural joint positions.
Avoid stretch: limit arm abduction (commonly aim ≤90°), avoid shoulder depression, avoid extreme elbow flexion/extension, avoid wrist hyperextension, avoid hip flexion/abduction/external rotation extremes.
Avoid compression: pad bony prominences; keep nerves off hard edges; avoid tight straps/tapes; ensure IV lines/ECG leads not under pressure points.
Perfusion: avoid prolonged hypotension; treat anaemia/hypovolaemia; maintain oxygenation; consider higher MAP targets when end-organ perfusion at risk (e.g., beach chair, ocular risk).
Re-checks: after final position, after draping, after major table movements, and at intervals in long cases; document checks and any limitations.
Documentation: position, padding, arm angles, head/eye protection, pressure areas checked, any pre-existing neuropathy/skin issues, and postoperative neuro/skin assessment plan.

Position-specific hazards and prevention

Supine
- Ulnar nerve compression at elbow; brachial plexus stretch with arm abduction/external rotation; pressure injury to occiput/sacrum/heels.
- Prevention: forearms supinated/neutral; pad elbows; avoid arm board abduction >90°; heels offloaded; sacral padding; avoid tight BP cuff/IV infiltration under pressure.
Lithotomy
- Common nerve injuries: common peroneal (fibular head), saphenous, femoral (hip flexion/abduction), obturator, sciatic; also low back strain, hip dislocation (rare), pressure injury to calves/heels.
- Compartment syndrome: lower limb (especially prolonged lithotomy + hypotension + external compression); can occur without obvious swelling under drapes.
- Prevention: well-padded stirrups; avoid pressure at fibular head; keep hips minimally flexed/abducted; avoid extreme external rotation; raise/lower legs together to avoid lumbosacral torsion; consider periodic leg lowering in very long cases if feasible.
Prone
- Ocular: perioperative visual loss (POVL) due to ischaemic optic neuropathy (ION) or central retinal artery occlusion (CRAO); corneal abrasion; direct globe pressure risk.
- Nerves: brachial plexus stretch (arm abduction/external rotation), ulnar nerve, radial nerve; lateral femoral cutaneous nerve (meralgia paraesthetica) from pelvic bolsters.
- Pressure/compartment: facial pressure necrosis; breast/genital injury; abdominal compression → reduced venous return, increased bleeding, reduced ventilation; rhabdomyolysis in prolonged cases/obesity.
- Prevention: head neutral; eyes free of pressure and checked after positioning and intermittently; abdomen free (frame/bolsters); arms tucked or abducted cautiously with padding; protect ulnar nerve; avoid excessive neck rotation; secure ETT and re-check after turning.
Lateral decubitus
- Brachial plexus injury: dependent shoulder compression; non-dependent arm over-abduction; ulnar nerve compression; common peroneal compression at fibular head of dependent leg.
- Ventilation/perfusion changes; risk of pressure injury to ear, greater trochanter, lateral knee/ankle.
- Prevention: axillary roll placed distal to axilla (under thorax) to offload axillary vessels/plexus; head/neck aligned; pad dependent ear/eye; pillow between legs; pad fibular head; secure patient to prevent sliding.
Trendelenburg / steep Trendelenburg (often robotic)
- Risks: facial/airway oedema; raised IOP/ICP; brachial plexus injury from shoulder braces; sliding/shear injuries; limited access after docking; aspiration risk with pneumoperitoneum.
- Prevention: avoid shoulder braces if possible (use non-slip mattress, cross-chest straps with padding, correct table tilt); secure ETT; consider cuff leak test before extubation if significant oedema; protect eyes; limit fluid overload; periodic assessment where possible.
Beach chair (sitting/semi-sitting)
- Risks: cerebral hypoperfusion (hydrostatic gradient between cuff and brain), venous air embolism (rare), hypotension/bradycardia (Bezold–Jarisch reflex especially with interscalene block), cervical spine strain, pressure injury to sacrum/heels.
- Prevention: measure BP at level of brain (or correct for height difference); avoid aggressive deliberate hypotension; maintain adequate MAP; secure head neutral; DVT prophylaxis; vigilance for sudden bradycardia/hypotension—treat promptly (fluids, vasopressors, anticholinergic).

Key named nerve injuries (high-yield)

Ulnar nerve (most common PNI in anaesthesia claims): compression at cubital tunnel/medial epicondyle; symptoms often delayed (hours–days): numbness/weakness in 4th/5th digits, intrinsic hand weakness.
Brachial plexus: stretch from arm abduction >90°, external rotation, shoulder depression, head turned away; also compression from shoulder braces in Trendelenburg.
Common peroneal: compression at fibular head (stirrups, lateral position); foot drop, sensory loss dorsum of foot.
Femoral: excessive hip flexion/abduction/external rotation (lithotomy), retractor compression; weak knee extension, reduced patellar reflex, anterior thigh/medial leg sensory loss.
Lateral femoral cutaneous: compression near ASIS/inguinal ligament (prone bolsters, obesity) → meralgia paraesthetica (anterolateral thigh burning pain).
Radial: compression in spiral groove (arm over edge, BP cuff, tourniquet) → wrist drop, dorsal hand sensory loss.

Ocular injuries (FRCA viva staple)

Corneal abrasion: most common ocular injury; risk with incomplete eyelid closure, drying, direct trauma (mask, drapes). Presents with pain, tearing, photophobia on waking.
POVL: rare but catastrophic; includes ION (often painless vision loss), CRAO (often with globe pressure; cherry-red spot), cortical blindness (rare). Risk factors: prone spine, long duration, major blood loss, anaemia, hypotension, large fluid shifts, raised venous pressure, obesity.
Prevention: tape eyelids closed; eye lubrication as per local policy; ensure no external pressure on eyes (especially prone); avoid prolonged severe hypotension/anaemia; consider staged surgery if very prolonged/high blood loss; document discussion in high-risk cases.

Compartment syndrome and rhabdomyolysis

Compartment syndrome: can follow prolonged lithotomy, tight leg supports, hypotension, vascular disease. Features: severe pain (out of proportion), pain on passive stretch, tense compartment; later pallor, pulselessness, paralysis are late signs.
Under GA/neuraxial, pain may be masked: look for unexplained tachycardia, rising lactate, swelling, metabolic acidosis, hyperkalaemia, myoglobinuria post-op.
Management: urgent surgical review; remove constriction; measure compartment pressures if uncertain; prompt fasciotomy is time-critical; treat rhabdomyolysis (fluids, manage K+, AKI prevention).
Rhabdomyolysis: prolonged pressure (prone, obese, long cases) → CK rise, myoglobinuria, AKI, hyperkalaemia; treat with aggressive IV fluids, monitor electrolytes/renal function, consider ICU.

Recognition and postoperative approach

Immediate postoperative assessment: document new numbness/weakness/visual symptoms; inspect pressure areas; check limb perfusion; ask about severe limb pain.
If suspected nerve injury: exclude reversible causes (tight dressings/casts, haematoma, compartment syndrome, malposition-related swelling); early neurology/hand team input if severe deficit; provide analgesia and safety-net advice.
Most PNIs are neuropraxia and improve over weeks; persistent deficits may need EMG/NCS (often most informative after ~2–3 weeks) and rehabilitation.
Duty of candour: explain suspected injury, plan, and follow-up; complete incident reporting; preserve documentation of positioning checks.

You are asked to anaesthetise a patient for a 6-hour robotic prostatectomy in steep Trendelenburg. What are your positioning concerns and how will you mitigate them?

Structure: risks → prevention → intraoperative checks → extubation considerations.

Risks: brachial plexus injury (shoulder braces), facial/airway oedema, raised IOP/ICP, corneal abrasion, sliding/shear injuries, limited access after docking, aspiration risk with pneumoperitoneum.
Mitigation: avoid shoulder braces if possible; use non-slip mattress and padded straps; arms tucked neutrally with padding; protect ulnar nerve; head/neck neutral; eyes taped and checked after positioning; secure ETT well; ensure IV lines not kinked/under pressure.
Physiology: avoid fluid overload; maintain perfusion; consider PEEP/ventilation strategy for pneumoperitoneum; plan for limited access (long extensions, emergency undocking plan).
End of case: assess for airway oedema (clinical; consider cuff leak test); be prepared for delayed extubation/ICU; document positioning and checks.

Describe the mechanisms of perioperative peripheral nerve injury and list patient and perioperative risk factors.

Mechanisms: compression (nerve between bone and hard surface), stretch (excess joint movement), ischaemia (pressure + hypotension/anaemia), inflammation/reperfusion injury.
Patient factors: diabetes, pre-existing neuropathy, obesity/low BMI, smoking, vascular disease, older age, malnutrition, pregnancy.
Perioperative factors: prolonged surgery, extreme positions, hypotension, hypothermia, vasopressors/low flow states, tight straps/tapes, hard arm boards, poor padding, limited access (robotic).

A patient wakes with numbness in the little finger and weakness of hand grip after surgery. What is the likely nerve injury, where is it injured, and how do you prevent it?

Likely injury: ulnar neuropathy.
Site/mechanism: compression at cubital tunnel/medial epicondyle; risk increased with elbow flexion and forearm pronation; can be delayed presentation.
Prevention: pad elbows; keep forearm supinated/neutral; avoid prolonged elbow flexion; ensure no hard edges/IV tubing under elbow; document arm position.

What nerve injuries are associated with the lithotomy position and how can they be prevented?

Nerves: common peroneal (fibular head), saphenous, femoral, obturator, sciatic; plus lumbosacral strain.
Prevention: well-padded stirrups; avoid pressure at fibular head; minimise hip flexion/abduction/external rotation; keep knees/ankles supported without focal pressure; raise/lower legs together; consider periodic leg lowering in prolonged cases if feasible.
Compartment syndrome vigilance in prolonged lithotomy, especially with hypotension/external compression.

A patient undergoing prolonged prone spinal surgery is at risk of perioperative visual loss. Explain the causes, risk factors, and preventive measures.

Causes: ischaemic optic neuropathy (anterior/posterior), central retinal artery occlusion (often from direct globe pressure), rarely cortical blindness.
Risk factors: prone spine, long duration, major blood loss, anaemia, hypotension, large crystalloid volumes, obesity, raised venous pressure (head down/abdominal compression).
Prevention: ensure no eye pressure and check eyes; head neutral; abdomen free to reduce venous congestion; avoid prolonged severe hypotension/anaemia; consider staging very long cases; careful fluid strategy; document discussion in high-risk cases.

How do you position and protect a patient in the lateral position? Include the purpose and correct placement of an axillary roll.

Goals: protect brachial plexus/axillary vessels, avoid pressure injuries (ear, shoulder, trochanter, fibular head), maintain head/neck alignment, prevent patient movement/sliding.
Axillary roll: placed under the thorax distal to the axilla (not in the axilla) to offload dependent shoulder/axillary structures and maintain chest wall expansion.
Arms: dependent arm supported on padded board; non-dependent arm on pillow/armrest without over-abduction; pad elbows and avoid ulnar compression.
Legs: pillow between knees/ankles; pad fibular head; protect lateral malleolus; ensure neutral hip/knee alignment.

In the beach chair position, why can cerebral perfusion be compromised and how should blood pressure be managed/monitored?

Hydrostatic gradient: BP cuff at arm may overestimate cerebral arterial pressure; brain MAP is lower by ~0.77 mmHg per cm height difference between cuff and brain.
Management: measure BP at level of external auditory meatus (or correct reading); avoid excessive deliberate hypotension; maintain adequate MAP especially in patients with cerebrovascular disease; treat sudden bradycardia/hypotension promptly (fluids, vasopressors, anticholinergic).

A patient in lithotomy for 5 hours has unexplained tachycardia and rising lactate. What positioning-related diagnosis must you consider and what is your immediate management?

Consider lower limb compartment syndrome and/or rhabdomyolysis (especially if hypotension/external compression).
Immediate actions: inform surgeon; assess legs if accessible (swelling/tense compartments); remove/loosen compression; optimise perfusion (treat hypotension/anaemia); urgent surgical review—do not delay fasciotomy if high suspicion.
Investigations/support: ABG, CK, U&Es/K+, urine for myoglobin; manage hyperkalaemia; consider ICU and aggressive fluids if rhabdomyolysis suspected.

Outline a practical intraoperative positioning checklist you would use before incision.

Head/neck neutral; eyes taped and free of pressure; ETT secured and rechecked after moves; bite block if needed.
Arms: abduction limited (aim ≤90°); forearms neutral/supinated; elbows padded; IV/arterial lines not kinked; avoid tight restraints.
Torso: pressure points padded (sacrum, scapulae); abdomen free in prone; straps padded to avoid shear.
Legs: heels offloaded; fibular head padded; stirrups symmetric; legs raised/lowered together in lithotomy.
Perfusion/temperature: MAP target agreed; avoid prolonged hypotension; warming in place; plan for periodic re-checks and documentation.

How would you manage and counsel a patient with suspected postoperative peripheral nerve injury?

Assess and document deficit (motor/sensory distribution), onset, severity; examine for reversible causes (tight dressings, haematoma, compartment syndrome, limb ischaemia).
Escalate early if severe/progressive: surgical team + neurology/hand team; consider imaging if compressive lesion suspected; analgesia (including neuropathic agents if appropriate) and physiotherapy/OT referral.
Explain prognosis: many are neuropraxia with gradual recovery; arrange follow-up; consider EMG/NCS after ~2–3 weeks if persistent; complete incident report and duty of candour.