1. Patient Positioning & Nerve Injuries
Karen Goodfellow
Anaesthetic F1

2. Importance of positioning
Minimise patient risk
Protect airway
Reduce blood loss
Prevent damage to
Nerves
Soft tissues
Bones
Control of extent of regional anaesthesia
Physiological changes
Optimise surgical access

3. Physiological changes
CVS
Postural hypotension
Head up
Venous pooling
Head down
Increased venous return
Respiratory
V/Q mismatch
↓ FRC

4. Supine

5. Supine position Most frequent Pressure areas Regurgitation Pregnancy
occiput, elbows, knees, sacrum, heels, greater trochanter
Regurgitation
Pregnancy
Aortocaval compression

6. Prone

7. Prone position
Spinal surgery, posterior cranial fossa, buttocks, heels
Importance of secure airway
Complications
Eye & neck trauma
Protection of eyes and neck
Horseshoe facial support
Abdominal compression
Supports to allow descent of diaphragm

8. Lithotomy

9. Lithotomy Urological, gynae and lower abdominal procedures
Legs moved simultaneously & symmetrically
Flexion of hips & knees <90˚
Complications
Hip dislocation
Digit entrapment
Common peroneal nerve damage
Compartment syndrome
Hypotension
?DVT

10. Trendelenburg

11. Trendelenburg Pelvic surgery Non-slip mattress
Ventilation for obese patients or long procedures
Complications
↓ diaphragmatic movement
Head & neck oedema
Reflux
Increased intraocular & intracranial pressure
Precipitation of heart failure

12. Reverse Trendelenburg
Head & neck surgery, upper GI & shoulder surgery
Complications
Postural hypotension
Venous air embolism

13. Lateral

14. Lateral Hip, thoracic & renal surgery Support of pelvis & shoulders
Protection of dependent arm
Complications
Wrong site surgery
V/Q mismatch
Compartment syndrome

15. Nerve injuries - why worry?
ASA Closed Claims Database ( )
32% death
16% nerve damage (670/4183)
12% brain damage
↑♂:♀
Of 670 nerve injuries
28% ulnar nerve
20% brachial plexus
16% lumbosacral nerve root
13% spinal cord

16. Types of injury
Neurapraxia
Axonotmesis
Neurotmesis

17. Neurapraxia Compression damage Usually incomplete Motor > sensory
Recovers <6/52

18. Axonotmesis Axonal & myelin loss Complete motor & sensory loss
Intact connective tissue sheath
Complete motor & sensory loss
Slow recovery 2˚ regeneration

19. Neurotmesis Partial or complete severance Recovery rare
Surgical repair sometimes possible
Traumatic neuroma

20. Causes of nerve injury General anaesthetic Poor positioning
Ischaemia
Hypotension & tourniquets
Hypothermia
Extravasation of drugs
Degradation products
Trichloroacetylene

21. Causes of nerve injury Local/regional anaesthesia Direct trauma
Intraneural LA
Cauda equina syndrome
Infection
Haematoma
Contamination of LA/wrong solution

22. Specific neuropathies
Ulnar nerve damage
Compression between humeral epicondyle & operating table

23. Ulnar neuropathy Acutely ~1/200 ♂:♀ = 3:1 RFs 85% associated with GA
Extremes of weight
Prolonged hospital stay
85% associated with GA
Delayed onset
Abnormal nerve conduction in contralateral, unaffected arm is common

24. Brachial plexus injury
Mechanism of injury
Stretched by abduction & extension
Compression by sternal retraction
Compression by shoulder retainers
Usually upper roots 1/

25. Lumbosacral root injury
1/5000 permanent damage
90% with regional
RFs (Auroy et al)
Paraesthesia
Pain during needle insertion
Pain on injection

26. Other neuropathies Nerve Aetiology Radial Arm unsupported Median
Needle trauma or drug extravasation in ACF
Facial
Compression during mask anaesthesia
Trigeminal
Trichloroethylene/soda lime interaction
Supraorbital
Compression by ventilator tubing
Common peroneal
Compression between lithotomy pole & fibular head
Saphenous
Compression between lithotomy pole & medial tibial condyle
Sciatic
IM injections or compression

27. Prevention Careful positioning Good anatomical knowledge
Documentation of pre-existing deficit

28. References
Fundamentals of Anaesthesia. 2nd Edition. Pinnock, Lin & Smith.
Anaesthesia & Intensive Care A-Z. 3rd Edition. Yentis, Hirsch & Smith.
Oxford Handbook of Anaesthesia. 2nd Edition. Allman & Wilson.
Bolton & Spencer. Positioning of the surgical patient. Anaesthesia & Intensive Care Medicine 2006; 7:
Cheney et al. Nerve injury associated with anaesthesia - a closed claims analysis. Anaesthesiology 1999; 90:
Auroy et al. Serious complications related to regional anaesthesia: Results of a prospective study in France. Anaesthesiology 1997; 87: