Trans-Ciliar Approach

Khaled M. A. Aziz, Nouman Aldahak, and Mohamed Arnaout

12.1 Introduction

The trans-ciliar approach represents a keyhole approach to the anterior cranial fossa and parasellar region, developed to minimize retraction on the frontal lobes in order to reach the pathology at hand.

As for other keyhole approaches the trauma to the superficial layers is minimal but the final exposure is sufficient to remove large tumors of this area and address selected vascular pathology of the anterior circulation.

12.2 Indications

• Aneurysms of the anterior circulation are the most commonly treated pathology including internal carotid artery, proximal anterior cerebral artery (ACA), anterior communicating artery (AcoA), posterior communicating artery (Pcom), proximal middle cerebral artery (MCA) and basilar tip.

• Tumors of the sellar and parasellar region and anterior skull base.

• Orbital lesions requiring craniotomy for exposure.

12.3 Brain Relaxation

• Head positioning: The head is positioned above the heart’s level.

• Mannitol, steroids.

• Lumbar drain (optional).

12.4 Patient Positioning (Fig. 12.1)

• Position: The patient is positioned supine with the head fixed with a Mayfield head holder.

• Body: The body is placed flat at 20° of reverse Trendelenburg position.

• A roll is put below the ipsilateral shoulder.

• Head:

◦ The head is elevated above the level of the heart (Fig. 12.1A.)

◦ It is rotated 15-30°according to the lesion approached, opposite to skin incision side (Fig. 12.1B.)

◦ A slight extension of about 20° toward the floor is provided (Fig. 12.1C.)

• The malar eminence has to be the highest point in the surgical field.

• Eye protection techniques:

◦ Lubricant to the ipsilateral eye.

◦ Ophthalmology eye shield.

◦ Ipsilateral tarsorrhaphy is recommended.

12.5 Skin Incision (Fig. 12.2)

• The incision is placed in the most superior margin of the eyebrow, which can be within a skin fold above the eyebrow (supraciliary).

• Starting point: The supraorbital notch can be considered as the medial limit of the incision.

• Course: Incision line runs over the eyebrow.

Fig. 12.1 Patient positioning: (A) 20° of reverse Trendelenburg position to elevate the head above the level of the heart. (B) Rotation 15-30° opposite to skin incision side. (C) The head is extended about 20° toward the floor.

Fig. 12.2 Skin incision. The pointed line reveals the possible lateral extension up to 1 cm, the arrow: the supraorbital notch.

• Ending point: Incision ends at the margin point of the tail of the eyebrow, it can be extended up to 1 cm laterally.

• The lateral extension of the incision should be sufficient to reveal the anterior edge of the temporal muscle and, with that, the frontobasal keyhole.

12.5.1 Critical Structures

• The supraorbital neurovascular bundle.

12.6 Soft Tissues Dissection (Fig. 12.3)

• Myofascial level

◦ Dissection through soft tissues is carried out in the direction of the skin incision.

• Muscles (Fig. 12.3)

◦ The frontalis muscle is incised along the direction of muscle fibers, parallel to the skin incision.

◦ The soft tissue dissection has to be carried out up to 3 cm above the orbital ridge.

◦ The temporal fascia and muscle are exposed.

• Bone exposure

◦ Landmarks for an orbital ridge periosteal incision:

– Medially: The supraorbital notch.

– Laterally: The lateral orbital tubercle.

◦ The periosteum is incised in U-shaped fashion based on the orbital ridge, then elevated.

◦ Elevation of the periosteum across the frontal bone is continued laterally beyond the frontozygomatic junction (Fig. 12.4).

◦ If an additional orbital osteotomy is planned, the subperiosteal dissection is carried down to orbital roof; the ocular globe should be protected in this step with a malleable retractor.

◦ Dissection of the temporal fascia and muscle from the superior temporal line is continued until the extracranial surface of the greater wing of the sphenoid bone is exposed (Fig. 12.5).