PROCEDURES

Mini Pterional approach

Mental Skills Required
icon_automatism
Automatism
icon_imagination
Imagination
icon_strategy
Strategy
Manual Skills Required
icon_automatism_manual
Automatism
icon_dexterity
Dexterity
icon_time
Speed
PROCEDURES

Mini Pterional approach

Mental Skills Required
icon_automatism
Automatism
icon_imagination
Imagination
icon_strategy
Strategy
Manual Skills Required
icon_automatism_manual
Automatism
icon_dexterity
Imagination
icon_time
Strategy
PROCEDURES

Mini Pterional approach

Mental Skills Required
icon_automatism
Automatism
icon_imagination
Imagination
icon_strategy
Strategy
Manual Skills Required
icon_automatism_manual
Automatism
icon_dexterity
Dexterity
icon_time
Speed
Needed for this topic

Tools involved:

Needed for this topic

Tools involved:

Needed for this topic

Tools involved:

Basic information

Allows the dissection of a large portion of the Sylvian fissure, and hence provides access to the anterior circulation and part of the posterior circulation.

Assess to:

  • The anterior cranial fossa
  • Peri- and suprasellar regions
  • Anterior third of the frontal and temporal opercula

Keep in mind

  • Consider whether the patient (location of the lesion are suitable for this type of approach)
  • Study carefully available images (CT, MR) to be prepared for anatomical rarities, use different section and projection 
  • Try to find the best route to the lesion with an avoidance of the excessive exposure and the retraction of brain tissue, otherwise use a different approach to reach the pathology
  • Keep in mind the general anatomy (skin layers, temporal muscle, skull bones, brain surface, carotido-optic triangle, the circle of Willis)
  • Be aware of possible slight distortion of the anatomy (patient is in the supine position and the head is rotated – effect of the gravity)
  • Try to project the anatomy on the skin surface

Basic information

Allows the dissection of a large portion of the Sylvian fissure, and hence provides access to the anterior circulation and part of the posterior circulation.

Assess to:

  • The anterior cranial fossa
  • Peri- and suprasellar regions
  • Anterior third of the frontal and temporal opercula

Keep in mind

  • Consider whether the patient (location of the lesion are suitable for this type of approach)
  • Study carefully available images (CT, MR) to be prepared for anatomical rarities, use different section and projection
  • Try to find the best route to the lesion with an avoidance of the excessive exposure and the retraction of brain tissue, otherwise use a different approach to reach the pathology
  • Keep in mind the general anatomy (skin layers, temporal muscle, skull bones, brain surface, carotido-optic triangle, the circle of Willis)
  • Be aware of possible slight distortion of the anatomy (patient is in the supine position and the head is rotated – effect of the gravity)
  • Try to project the anatomy on the skin surface

Basic information

Allows the dissection of a large portion of the Sylvian fissure, and hence provides access to the anterior circulation and part of the posterior circulation.

Assess to:

  • The anterior cranial fossa
  • Peri- and suprasellar regions
  • Anterior third of the frontal and temporal opercula

Keep in mind

  • Consider whether the patient (location of the lesion are suitable for this type of approach)
  • Study carefully available images (CT, MR) to be prepared for anatomical rarities, use different section and projection 
  • Try to find the best route to the lesion with an avoidance of the excessive exposure and the retraction of brain tissue, otherwise use a different approach to reach the pathology
  • Keep in mind the general anatomy (skin layers, temporal muscle, skull bones, brain surface, carotido-optic triangle, the circle of Willis)
  • Be aware of possible slight distortion of the anatomy (patient is in the supine position and the head is rotated – effect of the gravity)
  • Try to project the anatomy on the skin surface
icon_idea
icon_brain

Anatomy and important anatomical landmarks

  • Skull bones – frontal, sphenoid, temporal, parietal, zygomatic, zygomatic arch, pterion
  • Sphenoid wing
  • Tragus, temporal muscle line
  • Temporal muscle, facial nerve, superficial temporal artery, middle meningeal artery
  • Brain surface (temporal, frontal lobe)
  • Sylvian fissure
  • Carotico-optic triangle, carotico-oculomotor triangle
  • Circle of Willis
  • Contralateral structures (optic nerve, carotid artery)

Highlights

Sylvian fissure, circle of Willis, optic nerve
icon_brain

Anatomy and important anatomical landmarks

  • Skull bones – frontal, sphenoid, temporal, parietal, zygomatic, zygomatic arch, pterion
  • Sphenoid wing
  • Tragus, temporal muscle line
  • Temporal muscle, facial nerve, superficial temporal artery, middle meningeal artery
  • Brain surface (temporal, frontal lobe)
  • Sylvian fissure
  • Carotico-optic triangle, carotico-oculomotor triangle
  • Circle of Willis
  • Contralateral structures (optic nerve, carotid artery)

Highlights

Sylvian fissure, circle of Willis, optic nerve
icon_idea

Anatomy and important anatomical landmarks

  • Skull bones – frontal, sphenoid, temporal, parietal, zygomatic, zygomatic arch, pterion
  • Sphenoid wing
  • Tragus, temporal muscle line
  • Temporal muscle, facial nerve, superficial temporal artery, middle meningeal artery
  • Brain surface (temporal, frontal lobe)
  • Sylvian fissure
  • Carotico-optic triangle, carotico-oculomotor triangle
  • Circle of Willis
  • Contralateral structures (optic nerve, carotid artery)

Highlights

Sylvian fissure, circle of Willis, optic nerve
icon_positioning

Positioning

  • Supine position

 

  • Head rotation may change based upon the exact position of the area which must be exposed

Body positioning: supine (0°), supine lateral (45°)

Academy_miniPterional_approach_body_positioning
Patient is positioned supine
Academy_miniPterional_approach_body_positioning
In the case of extreme contralateral rotation, a supine lateral position can be used

Head positioning: contralateral rotation (40°), lateral tilt (10°), extension (12°)

Academy_minipterional_approach_Head_positioning_1

Rotation:

Contralaterally, from 15° to 60° depending on the position of the Region of Interest (ROI).

In general, more posterior and basal targets need more rotation.

Academy_minirpterional_approach_Head_positioning_2
Extension: From 10° to 30°, depending on the position of the ROI. In general, more basal and anterior targets need less extension of the head.
Academy_minipterional_approach_Head_positioning_3
Lateral tilt: A gentle tilt of 10° is needed to orient the vertex down. In general, the more basal target needs less lateral tilt.

Red Flags

Avoid over-rotation of the neck by elevating the ipsilateral shoulder. Head over the heart level. Regardless the position of the target, the malar eminence must always be the highest point of the operating field.
icon_positioning

Positioning

  • Supine position
  • Head rotation may change based upon the exact position of the area which must be exposed

Body positioning: supine (0°), supine lateral (45°)

Academy_miniPterional_approach_body_positioning
Patient is positioned supine
Academy_miniPterional_approach_body_positioning
In the case of extreme contralateral rotation, a supine lateral position can be used

Head positioning: contralateral rotation (40°), lateral tilt (10°), extension (12°)

Academy_minipterional_approach_Head_positioning_1

Rotation:
Contralaterally, from 15° to 60° depending on the position of the Region of Interest (ROI).

In general, more posterior and basal targets need more rotation.

Academy_minirpterional_approach_Head_positioning_2

Extension:
Extension: From 10° to 30°, depending on the position of the ROI. In general, more basal and anterior targets need less extension of the head.

Academy_minipterional_approach_Head_positioning_3
Lateral tilt: A gentle tilt of 10° is needed to orient the vertex down. In general, the more basal target needs less lateral tilt.

Red Flags

Avoid over-rotation of the neck by elevating the ipsilateral shoulder. Head over the heart level. Regardless the position of the target, the malar eminence must always be the highest point of the operating field.
icon_positioning

Positioning

  • Supine position

 

  • Head rotation may change based upon the exact position of the area which must be exposed

Body positioning: supine (0°), supine lateral (45°)

Academy_miniPterional_approach_body_positioning
Patient is positioned supine
Academy_miniPterional_approach_body_positioning
In the case of extreme contralateral rotation, a supine lateral position can be used

Head positioning: contralateral rotation (40°), lateral tilt (10°), extension (12°)

Academy_minipterional_approach_Head_positioning_1

Rotation:
Contralaterally, from 15° to 60° depending on the position of the Region of Interest (ROI).

In general, more posterior and basal targets need more rotation.

Academy_minirpterional_approach_Head_positioning_2
Extension:
From 10° to 30°, depending on the position of the ROI. In general, more basal and anterior targets need less extension of the head.
Academy_minipterional_approach_Head_positioning_3
Lateral tilt:
A gentle tilt of 10° is needed to orient the vertex down. In general, the more basal target needs less lateral tilt.

Red Flags

Avoid over-rotation of the neck by elevating the ipsilateral shoulder. Head over the heart level. Regardless the position of the target, the malar eminence must always be the highest point of the operating field.
icon_surgery

Surgery

1. Skin incision N°22 scalpel blade

MiniPterional_01
The incision should stay behind the hairline; in those patients with high hairline it is advisable to make a wider skin incision passing behind the hairline. The inferior end of the incision is placed anterior to the tragus (5 mm approx.).
MiniPterional_01
The superior end is at the level of the midline. These two points must be connected with an arcuate line.

2. Initial dissection of the skin flap with elevator

MiniPterional_02
Skin and pericranium can be cut and detached from the skull in one layer.

3. Placement of hemostatic clips

MiniPterional_03
Avoiding an excessive cauterization of the subcutaneous layers facilitates better skin healing.

4. Skin flap elevation with elevator

MiniPterional_04
It is possible to use the same techniques in this stage as were applied in the initial skin flap dissection.

5. Dissection of temporal muscle

MiniPterional_05
The temporal muscle is cut with monopolar cautery along the superior temporal line attachment. Then a vertical posterior incision along the muscle’s fibers is done creating a “L” shaped myofascial incision.

6. Burr hole with perforator

MiniPterional_06
A single burr hole is placed onto the pterion or behind the frontozygomatic suture.

7. Preparation of the burr holes with dura separator

MiniPterional_07
This step helps to reduce the risk of tearing the dura mater during the craniotomy. The risk is higher in elderly patients because of the strong adherence between the inner table of the skull and dura.

8. Craniotomy with high-speed drill

MiniPterional_08
Proceed with performing the craniotomy, paying attention to maintaining the orientation of the drill perpendicular to the skull surface.

9. Edge drilling with high-speed drill

MiniPterional_09
After removing the bone flap, a fundamental step is to drill down the anterior cranial base, orbital roof and lesser wing of the sphenoid bone. Accurate drilling facilitates optimal access to the skull base and basal cistern, reducing the necessity of brain retraction.

10. Dural tenting sutures

MiniPterional_10
Transosseous stitches are used to suspend the dura and reduce extradural bleeding.

11. Dura incision with N°10 scalpel blade and scissor

MiniPterional_11
Dura should be incised in a C-shape and reflected toward the cranial base.
icon_surgery

Surgery

1. Skin incision N°22 scalpel blade

MiniPterional_01
The incision should stay behind the hairline; in those patients with high hairline it is advisable to make a wider skin incision passing behind the hairline. The inferior end of the incision is placed anterior to the tragus (5 mm approx.).
MiniPterional_01
The superior end is at the level of the midline. These two points must be connected with an arcuate line.

2. Initial dissection of the skin flap with elevator

MiniPterional_02
Skin and pericranium can be cut and detached from the skull in one layer.

3. Placement of hemostatic clips

MiniPterional_03
Avoiding an excessive cauterization of the subcutaneous layers facilitates better skin healing.

4. Skin flap elevation with elevator

MiniPterional_04
It is possible to use the same techniques in this stage as were applied in the initial skin flap dissection.

5. Dissection of temporal muscle

MiniPterional_05
The temporal muscle is cut with monopolar cautery along the superior temporal line attachment. Then a vertical posterior incision along the muscle’s fibers is done creating a “L” shaped myofascial incision.

6. Burr hole with perforator

MiniPterional_06
A single burr hole is placed onto the pterion or behind the frontozygomatic suture.

7. Preparation of the burr holes with dura separator

MiniPterional_07
This step helps to reduce the risk of tearing the dura mater during the craniotomy. The risk is higher in elderly patients because of the strong adherence between the inner table of the skull and dura.

8. Craniotomy with high-speed drill

MiniPterional_08
Proceed with performing the craniotomy, paying attention to maintaining the orientation of the drill perpendicular to the skull surface.

9. Edge drilling with high-speed drill

MiniPterional_09
After removing the bone flap, a fundamental step is to drill down the anterior cranial base, orbital roof and lesser wing of the sphenoid bone. Accurate drilling facilitates optimal access to the skull base and basal cistern, reducing the necessity of brain retraction.

10. Dural tenting sutures

MiniPterional_10
Transosseous stitches are used to suspend the dura and reduce extradural bleeding.

11. Dura incision with N°10 scalpel blade and scissor

MiniPterional_11
Dura should be incised in a C-shape and reflected toward the cranial base.
icon_surgery

Surgery

1. Skin incision N°22 scalpel blade

MiniPterional_01
The incision should stay behind the hairline; in those patients with high hairline it is advisable to make a wider skin incision passing behind the hairline. The inferior end of the incision is placed anterior to the tragus (5 mm approx.).
MiniPterional_01
The superior end is at the level of the midline. These two points must be connected with an arcuate line.

2. Initial dissection of the skin flap with elevator

MiniPterional_02
Skin and pericranium can be cut and detached from the skull in one layer.

3. Placement of hemostatic clips

MiniPterional_03
Avoiding an excessive cauterization of the subcutaneous layers facilitates better skin healing.

4. Skin flap elevation with elevator

MiniPterional_04
It is possible to use the same techniques in this stage as were applied in the initial skin flap dissection.

5. Dissection of temporal muscle

MiniPterional_05
The temporal muscle is cut with monopolar cautery along the superior temporal line attachment. Then a vertical posterior incision along the muscle’s fibers is done creating a “L” shaped myofascial incision.

6. Burr hole with perforator

MiniPterional_06
A single burr hole is placed onto the pterion or behind the frontozygomatic suture.

7. Preparation of the burr holes with dura separator

MiniPterional_07
This step helps to reduce the risk of tearing the dura mater during the craniotomy. The risk is higher in elderly patients because of the strong adherence between the inner table of the skull and dura.

8. Craniotomy with high-speed drill

MiniPterional_08
Proceed with performing the craniotomy, paying attention to maintaining the orientation of the drill perpendicular to the skull surface.

9. Edge drilling with high-speed drill

MiniPterional_09
After removing the bone flap, a fundamental step is to drill down the anterior cranial base, orbital roof and lesser wing of the sphenoid bone. Accurate drilling facilitates optimal access to the skull base and basal cistern, reducing the necessity of brain retraction.

10. Dural tenting sutures

MiniPterional_10
Transosseous stitches are used to suspend the dura and reduce extradural bleeding.

11. Dura incision with N°10 scalpel blade and scissor

MiniPterional_11
Dura should be incised in a C-shape and reflected toward the cranial base.

Microexploration

A1: Anterior Cerebral Artery, First Segment

AComA: Anterior Communicating Artery

A2: Anterior Cerebral Artery, Second Segment

ICA- Bif: Internal Carotid Artery (ICA) bifurcation

M1: Middle Cerebral Artery, First Segment

MCA-Bif: Middle Cerebral Artery) bifurcation

M2: Middle Cerebral Artery, Second Segment

PComA: Posterior Communicating Artery

CN I: Cranial Nerve I, Olfactory Nerve

CN II: Cranial Nerve II, Optic Nerve

CN III: Cranial Nerve III, Oculomotor Nerve

Chiasm: Optic Chiasm

MTR (anterior third): Mesial temporal region (anterior third)

Limen: Limen Insulae

Insula: Insula

ACP: Anterior Clinoid Process

PCP: Posterior Clinoid Process

LW: Lesser Wing

Microexploration

A1: Anterior Cerebral Artery, First Segment

AComA: Anterior Communicating Artery

A2: Anterior Cerebral Artery, Second Segment

ICA- Bif: Internal Carotid Artery (ICA) bifurcation

M1: Middle Cerebral Artery, First Segment

MCA-Bif: Middle Cerebral Artery) bifurcation

M2: Middle Cerebral Artery, Second Segment

PComA: Posterior Communicating Artery

CN I: Cranial Nerve I, Olfactory Nerve

CN II: Cranial Nerve II, Optic Nerve

CN III: Cranial Nerve III, Oculomotor Nerve

Chiasm: Optic Chiasm

MTR (anterior third): Mesial temporal region (anterior third)

Limen: Limen Insulae

Insula: Insula

ACP: Anterior Clinoid Process

PCP: Posterior Clinoid Process

LW: Lesser Wing

Microexploration

A1: Anterior Cerebral Artery, First Segment

AComA: Anterior Communicating Artery

A2: Anterior Cerebral Artery, Second Segment

ICA- Bif: Internal Carotid Artery (ICA) bifurcation

M1: Middle Cerebral Artery, First Segment

MCA-Bif: Middle Cerebral Artery) bifurcation

M2: Middle Cerebral Artery, Second Segment

PComA: Posterior Communicating Artery

CN I: Cranial Nerve I, Olfactory Nerve

CN II: Cranial Nerve II, Optic Nerve

CN III: Cranial Nerve III, Oculomotor Nerve

Chiasm: Optic Chiasm

MTR (anterior third): Mesial temporal region (anterior third)

Limen: Limen Insulae

Insula: Insula

ACP: Anterior Clinoid Process

PCP: Posterior Clinoid Process

LW: Lesser Wing

icon_surgery

Closure

1. Dura reconstruction

MiniPterional_12
A water-tight closure of the dura is always needed, particularly in cases of cisternal and ventricular opening. In case of dura retraction, several types of synthetic substitutes or a galea flap can be used to complete the approximation.

2. Bone fixation with microscrews

MiniPterional_13
At least 3 microplates are used to guarantee the immobility of the bone flap. Immobility is necessary for osteosynthesis. For bigger craniotomies, central dural suspensions are mandatory.

3. Muscle reconstruction

MiniPterional_14
Temporal muscle is sutured – this mitigates the risk of chewing problems postoperatively.

4. Subcutaneous/skin suture

MiniPterional_15

Aesthetic skin reconstruction is always mandatory.

icon_surgery

Closure

1. Dura reconstruction

MiniPterional_12
A water-tight closure of the dura is always needed, particularly in cases of cisternal and ventricular opening. In case of dura retraction, several types of synthetic substitutes or a galea flap can be used to complete the approximation.

2. Bone fixation with microscrews

MiniPterional_13
At least 3 microplates are used to guarantee the immobility of the bone flap. Immobility is necessary for osteosynthesis. For bigger craniotomies, central dural suspensions are mandatory.

3. Muscle reconstruction

MiniPterional_14
Temporal muscle is sutured – this mitigates the risk of chewing problems postoperatively.

4. Subcutaneous/skin suture

MiniPterional_15
Aesthetic skin reconstruction is always mandatory.
icon_surgery

Closure

1. Dura reconstruction

MiniPterional_12
A water-tight closure of the dura is always needed, particularly in cases of cisternal and ventricular opening. In case of dura retraction, several types of synthetic substitutes or a galea flap can be used to complete the approximation.

2. Bone fixation with microscrews

MiniPterional_13
At least 3 microplates are used to guarantee the immobility of the bone flap. Immobility is necessary for osteosynthesis. For bigger craniotomies, central dural suspensions are mandatory.

3. Muscle reconstruction

MiniPterional_14
Temporal muscle is sutured – this mitigates the risk of chewing problems postoperatively.

4. Subcutaneous/skin suture

MiniPterional_15
Aesthetic skin reconstruction is always mandatory.

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Supported by the European Union

This project has received funding from the Eropean Union's H2020 Research and Innovation Programme under grant agreement n.880895

Supported by the European Union

This project has received funding from the Eropean Union's H2020 Research and Innovation Programme under grant agreement n.880895

Supported by the European Union

This project has received funding from the Eropean Union’s H2020 Research and Innovation Programme under grant agreement n.880895

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