Mini Pterional approach

Mental Skills Required




Manual Skills Required




Mental Skills Required




Manual Skills Required




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

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)


Sylvian fissure, circle of Willis, optic nerve


  • 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°)

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

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.


1. Skin incision N°22 scalpel blade

2. Initial dissection of the skin flap with elevator

3. Placement of hemostatic clips

4. Skin flap elevation with elevator

5. Dissection of temporal muscle

6. Burr hole with perforator

7. Preparation of the burr holes with dura separator

8. Craniotomy with high-speed drill

9. Edge drilling with high-speed drill

10. Dural tenting sutures

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


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


1. Dura reconstruction

2. Bone fixation with microscrews

3. Muscle reconstruction

4. Subcutaneous/skin suture

Pterional Box: brain box for pteronial approach

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