026 positioning for cranial surgery

Positioning for cranial surgery

Youmans Chapter 26

Outline

• Pterional (frontotemporal) craniotomy• Temporal and subtemporal approach• Anterior parasagittal and subfrontal approaches• Posterior parasagittal craniotomy• Midline suboccipital craniotomy• Lateral suboccipital approach• Transsphenoidal approach

Pterional (frontotemporal) craniotomy


• Most common• Approach

– supratentorial intracerebral aneurysms– pathologic processes of the anterior, middle cranial

fossae and posterior cranial fossa– the central skull base


• Positioning– Supine position, reverse Trendelenburg– Mayfield-Kees head fixation

• The single pin is placed in the frontal bone contralateral to the operative target, approximately 2 to 3 cm above the brow

• The dual pins are then placed in the occipital bone on the ipsilateral side

• Pins along the axial plane, may be saggital plane– Shoulder roll is placed under the ipsilateral

shoulder along axis


• Position– Head

• Head is rotate toward the contralateral shoulder• The degree of rotation can vary greatly and is largely

dependent on the desired surgical target • internal carotid artery disease : 5-20o

• anterior communicating artery aneurysms : 60o

• wide opening of the sylvian fissure : avoidance of excessive rotation

• head is laterally flexed slightly, followed by an extension of the neck


• Position– This last maneuver should present the malar

eminence as the highest point– Once it is in position, the head fixation device is

secured to the table– Pillows and padding are placed under the

patient’s knees and feet– patient is secured to the table with a padded safety

belt or padding and tape

Temporal and subtemporal approach


• Perform alone for petrous disease, other disease of the middle fossa, or basilar apex aneurysms

• Performed in conjunction with another approach, such as the pterional or lateral suboccipital craniotomy


• Position– lateral park bench position, reverse Trendelenburg

position– Mayfield-Kees head fixation

• The single pin clamp into the frontal bone 2 to 3 cm above the ipsilateral brow

• The dual pins in the occipital bone along the axial plane at midline and contralateral to the surgical site


• Position– Arms

• inferior arm extended perpendicular to the patient’s body on an arm board

• dependent arm is properly positioned• placed in neutral position along the long axis of the

torso, with slight flexion at the elbow– the neck is laterally flexed


• Position– The head fixation apparatus is then secured to the

table, and the patient’s body is supported with safety belts and tape

– Alternatively, the temporal or subtemporal approach can be accomplished with the patient in the supine position as long as the patient’s neck is supple and 90 degrees of rotation can be accomplished easily.

Anterior parasagittal and subfrontal approaches


• Different in degree of head flexion• The anterior parasagittal approach

– interhemispheric approaches : lesions of the anterior interhemispheric fissure, distal anterior cerebral artery aneurysms, access to the third or lateral ventricles for colloid cysts ,intraventricular disease

• The subfrontal approach– anterior cranial fossa : meningiomas from the

olfactory groove to the tuberculum sellae


• Position– Supine– Mayfield-Kees head fixation

• The dual pins are placed behind the ear in the coronal plane

• the single pin is placed at approximately the same point on the contralateral side

– the patient is strapped in with a waist belt– the head of the bed is raised until the vertex of the

patient’s head is within the focal length of the neurosurgeon


• Position– For the anterior parasagittal craniotomy, the head is

flexed until the point of the planned craniotomy and the planned target are along a comfortable trajectory for the neurosurgeon

– For the subfrontal approach, it is often necessary to actually extend the head slightly until the brow is the most superior point on the operative field

– The head is secured. The patient is then secured to the table with pressure points padded as outlined before


• Position– An alternative positioning strategy for the anterior

parasagittal approach is to have the patient in a lateral position, with the side down depending on the pathologic process and the angle of attack

– The head is then tilted upward until the surgical target is in the appropriate location, placing the pathologic process in the horizontal plane

– Use for : parasagittal meningiomas, contralateral hemisphere through a transcallosal approach

Posterior parasagittal craniotomy

• Supine position– Craniotomy is within several centimeters posterior

to the cranial vertex, awake craniotomy– Mayfield-Kees head clamp

• the pins oriented in the axial plane• the posterior of the dual pins approximately 2 to

3 cm above the external auditory meatus• the single pin slightly anterior to this point on the

opposite side.


• Supine position– the bed is flexed slightly until the site of the

craniotomy is in the desired position– If an awake craniotomy is planned, the neck should

remain in neutral position, with the thighs typically elevated to increase the patient’s comfort


• Prone position– the pins are placed before the patient is flipped– Mayfield-Kees head clamp

• the pins oriented in the axial plane• the posterior of the dual pins approximately 2 to

3 cm above the external auditory meatus• the single pin slightly anterior to this point on the

opposite side.– Patient placed prone on the operative table


• Prone position– arms are placed in the neutral position and are

padded and tucked to the patient’s side– The patient’s chest lies on soft gel rolls placed parallel

to the long axis of the body– It is important to avoid leaving electrocardiogram

leads or wires on or across the anterior chest wall because this can produce pressure sores or abrasions


• Prone position– Once the patient is strapped in, the bed is flexed

into the Concorde position– the final manipulation entails extension or flexion of

the neck. The degree of flexion depends on the exact location of the planned craniotomy

Midline suboccipital craniotomy


• Approch– Fourth ventricular lesion– midline cerebellar lesions– Pineal lesion


• Prone position– Mayfield-Kees head fixation

• the pins just below the superior temporal line on both sides

• The dual pin side is typically placed so that the posterior pin is 2 to 3 cm above the external auditory meatus;

• The single pin is placed slightly anterior at the same level on the contralateral side


• Prone position– The patient is placed prone on the operative table

onto two large chest rolls, and the arms are tucked into neutral position along the length of the patient

– The patient is strapped to the bed with a waist belt– Concorde position and reverse Trendelenburg– the head is flexed until the chin is at least two

fingerbreadths from the sternal notch– craniotomy site is the most superior point of the

patient


• Seated position– supracerebellar infratentorial position– the cerebellum falls away from the tentorium after

arachnoidal adhesions are divided, and it provides a bloodless field


• Mayfield-Kees head fixation– the pins just below the superior temporal line on

both sides– The dual pin side is typically placed so that the

posterior pin is 2 to 3 cm above the external auditory meatus;

– The single pin is placed slightly anterior at the same level on the contralateral side


• Seated position– The patient is strapped in with a waist belt, and the

back is elevated until the patient is in the seated position

– The head is then flexed slightly before the Mayfield-Kees head clamp is secured

– The arms are then placed across the patient’s abdomen and secured

– The lower extremities are often wrapped in compression stockings or wrap to facilitate venous return

Lateral suboccipital approach


• Approach– cerebellopontine angle – lateral cerebellum– posterior circulation aneurysms– aneurysms of the anterior inferior cerebellar artery– microvascular decompression of the trigeminal nerve


• number of positions– modified Concorde position– lateral park bench position– supine position– seated position


• modified Concorde position• the patient is positioned exactly as with the midline

suboccipital approach• Modified by rotation of the patient’s head

approximately 45 degrees to the shoulder ipsilateral to the lesion before the head is fixed in the Mayfield clamp


• The park bench position– The patient is positioned as described for the

subtemporal craniotomy– rotating the face slightly toward the floor– the Mayfield-Kees head clamp is parallel to the

floor and presents the craniotomy site as the most prominent part of the operative field

– It is important to pad pressure points and to add an axillary roll as described for the temporal or subtemporal approach


• sitting position– Mayfield-Kees head fixation

• the dual pins are placed 2 to 3 cm above the external auditory

• the single pin is placed 2 to 3 cm superior and anterior to the external auditory meatus

– The patient is strapped in with a waist belt, and the back is elevated until the patient is in the seated position

– The bed is then flexed, with an elevation of the thighs and flexion of the knees


• sitting position– The arms are then placed across the patient’s

abdomen and secured– The head is then flexed slightly and rotated,

depending on the pathologic process at hand, before the Mayfield-Kees head clamp is secured

Lateral suboccipital approachAdvantage Disadvantage

modified Concorde position

-comfortable for the surgeon-cerebellopontine angle disease (gravity aid)

-risk of air embolus-risk of pressure sores and blindness from elevated intraocular pressures

park bench position

-facilitates cerebellar retraction-comfortable position for the operating surgeon

-brachial plexus injuries -other stretch injuries

sitting position -lowering intracranial pressure-the anesthesiologist superior access to the face- clear, bloodless field

-higher risk of venous air embolism-tension pneumocephalus-subdural hematomas-can create fatigue for the surgeon operating

Transsphenoidal approach


• It is imperative that the patient be positioned correctly, ensuring that the correct trajectory is taken

• Complication : opening of the anterior cranial fossa


• Positioning for the endoscopic endonasal approach– Supine position– The head is placed on a horseshoe headrest, – the right arm is tucked with the hand positioned

underneath the right thigh– The patient is then strapped in by a belt across the

thighs– The bed is turned so that the feet are

approximately 30 degrees to the patient’s left in relation to the head


• Positioning for the endoscopic endonasal approach– the bed is flexed into a beach chair position– reverse Trendelenburg positioning– The bed is then tilted slightly to the right– the bridge of the nose parallel to the floor


• Positioning for the sublabial microscopic approach– Supine position– The arms are tucked, and the patient is again belted

in with a strap across the thighs– The patient is placed in the Mayfield-Kees pins– The pins are placed behind the ears to reduce

potential obstruction of fluoroscopic images


• Positioning for the sublabial microscopic approach– Before the head is secured, the head of the bed is

elevated– The head is then flexed until the bridge of the nose is

approximately 45 degrees from the horizontal axis– The head is rotated to the patient’s right until the

patient is face-to-face with the surgeon before the Mayfield is finally locked in

Thank you

Date post:	10-Apr-2017
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026 positioning for cranial surgery

Health & Medicine