1) Proper positioning is important in neurosurgery to optimize exposure while ensuring patient safety and physiological stability. Different positions like supine, prone, lateral and sitting are used depending on the surgical site. 2) Positions can affect respiratory, cardiovascular and central nervous systems through changes in venous return, ventilation/perfusion matching, intracranial pressure and nerve stretching. Careful positioning and monitoring are needed to prevent complications. 3) Special equipment like Mayfield head holders, horseshoe frames and Wilson frames help achieve and maintain desired positions for optimal surgical access and exposure.

1. POSITIONING IN
NEUROANAESTHESIA
MODERATOR – Dr. Divya Chandra Ma’am
PRESENTER – Dr. Himanshu Baxy

2. • IMPORTANCE OF PROPER POSITIONING
• DIFFERENT POSITIONS AND ASSCOCIATED PHYSIOLOGY
• EQUIPMENTS USED FOR POSITIONING IN NEUROSURGERIES

3. IMPORTANCE OF PROPER POSITIONING
• Proper positioning for optimal exposure of brain
• Physically and physiologically safe for patient
• Adverse effects of different positions
• Before and after positioning – Secure the Endotracheal tube

4. RAISED INTRACRANIAL PRESSURE
• Increased Intraabdominal pressure
• Excessive flexion of neck – Jugular Venous drainage is impeded
• If head is below the level of Heart

5. VENOUS CONGESTION
Venous congestion : ↑brain swelling & ↑venous bleeding
It can occur due to –
• Insufficient abdominal bolstering
• ↑PEEP
• Hyperrotation or hyperflexion of neck

6. AIRWAY COMPROMISE
• Hyperflexion of Neck can cause kinking of ETT
• Can be prevented by using flexometallic ET tubes
• While flexion keep a distance of two fingers between CHIN and CHEST
STAINLESS STEEL
SPIRAL CORE

7. • Prolonged pressure on pressure area points
• Stretching of nerves – For eg Brachial plexus in
hyperabduction of shoulder
• Corneal abrasions – Do proper eye padding with Eye
ointment

8. HEAD UP
• Head is elevated to 15 to 30 degrees – To facilitate venous and CSF
drainage
• Avoided in – 1) After evacuation of Sub Dural Hemorrhage
2) CSF shunting – to prevent too rapid collapse of
ventricles

9. 1. Supine
2. Prone
3. Lateral
4. Semi – Lateral (Janetta)
5. Semi – Prone (Park bench)
6. Sitting

10. SUPINE POSITION

11. • Head – Neutral/Rotated/Flexed
• Upper limbs at the side
• Do NOT abduct shoulders more than 90 degrees
• Padding to elbow and wrist
• Knees elevated and heels padded

12. Respiratory System Physiological changes in Supine position
Cephalad push of diaphragm
↓FRC
Alveoli closes at a volume close to FRC
Dorsal airways cant participate in gas exchange
V-P mismatch
↓COMPLIANCE

13. Increased perfusion in Dorsal Aspect of lungs
But compliance is reduced
Ventral lungs have same perfusion
But Ventilation is increased
Hence there is VP mismatch

14. CARDIOVASCULAR SYSTEM in Supine position
↑ Venous return
↑CO - baroreceptor reflexes
↑ CO and SV
↑ Blood Pressure
This is the normal response in supine postion however Anaesthesia,
muscle relaxant and PPV interefere with venous return.
Hence circulatory effects of positioning remain uncompensated

15. Reverse Trendlenberg : increase in head and neck venous drainage,
reduction in intracranial pressure and reduced likelihood of passive
regurgitation

17. PRONE POSITION
For spinal cord, suboccipital approach/occipital lobe, craniosynostosis
and posterior fossa procedures.
Can cause hemodynamic changes, impairement of ventilation and
spinal cord injury
Anaesthesiologist should have a plan for detaching and reattaching
monitors in an orderly manner to prevent excessive monitoring
‘window’. Needs coordination of members.

18. CARDIOVASCULAR RESPONSE TO PRONE
POSITION
• In prone position, the IVC gets compressed and this causes reduced
venous return. This in turn causes hypotension.
• This can be prevented by placing the patient on two bolsters placed
sufficiently far apart.
• This is done to prevent compressing abdominal and femoral venous
return. And to allow adequate diaphragm movement.

19. Wilson’s Frame for prone position

20. PRONE POSITION - RESPIRATORY SYSTEM
• If bolsters are correctly placed, chest and abdomen hang free;
ventilation accoplished with normal pressures
• FRC decrement seen in supine position is not seen with prone
position

21. CENTRALNERVOUS SYSTEM
• Vertebral venous plexus have anastomotic connections with IVC &
femoral vein
• Compression of IVC - diversion of blood to vertebral venous plexus -
↑ bleeding, ↓visibility in spine surgery

22. Horse Shoe Rest

23. Prevent injury to Brachial Plexus
• Arms should NOT be abducted >90⁰; elbows shouldnt be
extended>90⁰ [90-90 position]
• Elbow should be anterior to the shoulder to prevent wrapping of
brachial plexus around head of humerus
• Pronation makes ulnar nerve very vulnerable, while supination keeps
it in a more protected position

24. LATERAL POSITION

25. LATERAL POSITION
• For access to posterior parietal and occipital lobes and lateral
posterior fossa
• Includes C-P angle tumours and vertebral/basilar aneurysms
• Key feature: Use of axillary roll to prevent brachial plexus injury or
pressure on dependent shoulder
• Rolls themselves can cause harm; prevented by placing the axillary
roll caudal to axilla
• Pulse to be monitored in dependent arm
• Knees flexed with paddings between the knees to avoid pressure over
the fibular head and peroneal nerve

26. Physiology in Lateral Position
• RESPIRATORY SYSTEM: non dependent lung is well ventilated, but
poorly perfused and dependent lung is well perfused but poorly
ventilated - V/Q mismatch

27. SEMI-LATERAL/JANETTA POSITION
• Supine position with a bolster
• For petrosal, retromastoid & U/L frontotemporal approaches
• Lateral tilting of the table, 10-20⁰ with I/L shoulder elevated
• Named after the neurosurgeon who popularized its use for
microvascular decompression of 5th nerve

29. PARK BENCH / SEMI-PRONE POSITION
Used in far lateral approaches
placing the patient sufficiently superiorly
on the operating table such that the
dependent arm is hanging over the edge
of the table & secured with a sling
Trunk is rotated 15⁰ from lateral position
into a semiprone position & supported
with pillows.
Non dependent shoulder is pulled
inferiorly

30. SITTING POSITION
• Modified recumbent position
• Skull secured in three pin head holder
[applied while on supine].
• Infiltration of scalp & periosteum @ pin
sites
• Legs placed in thigh-high compression
stockings

31. Advantages of sitting position
• Excellent surgical exposure
• Reduced perioperative blood loss
• Reduced facial swelling
• Superior access to airway
• Improved ventilation, particularly in obese patients

32. Physiology in sitting position
1) cvs - Hypotension
For each 1.25 cm movement of head above heart,
Local arterial pressure reduces by 1 mmHg
Measures to prevent Hypotension -
-PREPOSITIONING HYDRATION
-WRAPPING OF LEGS WITH ELASTIC BANDAGES
-SLOW INCREMENTAL ADJUSTMENT OF THE TABLE
It is important to maintain CPP @ a minimum of 60
mm of Hg

33. Respiratory system
• FRC & VC improved
• Hypovolemia may decrease upper lung perfusion - V-P mismatch /
hypoxia
• N2O controversial

34. AWAKE CRANIOTOMIES (STEREOTACTIC
SURGERY)
• Done for treating involuntary movements (parkinsonism)
• Surgeon needs awake patient to locate exact focus
• Asleep –awake – asleep technique
• Asleep for painful part (reaching upto dura)
• Awake for procedure
• Asleep for painful part - closure

35. EQUIPMENTS USED FOR POSTIONING IN
NEUROSURGERIES
1) Pin (Mayfield) head holder
• Skull block before application
• Placed in a band like area just above orbits & pinna [~sweatband]
• Avoid over thin temporal bone; caution when over frontal sinus
• Coated with antibiotic ointment

37. 2) Horseshoe Headrest

38. 3) Wilson’s Frame

39. THANK YOU