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Updated: Jun 17, 2026

Minimally Invasive Thumb-sized Pterional Craniotomy for Surgical Clip Ligation of Unruptured Anterior Circulation Aneurysms
Published on: August 11, 2015
The Lateral Supraorbital Approach: 2-Dimensional Operative Video
Hugo Andrade-Barazarte1,2, Juha Hernesniemi2
1Department of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Canada.
Indications:
The lateral supraorbital approach (LSO), a minimally invasive alternative to the pterional approach, can be used for anterior circulation aneurysms (except distal anterior cerebral artery), some posterior circulation aneurysms, and tumors located around the sellar and suprasellar regions.
Anatomic Essentials:
Performing one-layer myocutaneous flap that is retracted anteriorly, exposure of the superior temporal line, and zygomatic process of the frontal bone and the inferior limit of the craniotomy represent the upper edge of the Sylvian fissure, exposing the anterolateral skull base.
Essentials Steps:
Skin incision behind the hairline, one-layer myocutaneous flap retracted anteriorly, minimal detachment of the temporalis muscle, burr hole over the superior temporal line, and craniotomy of 4 cm in diameter (inferior limit of the craniotomy represents the Sylvian fissure).
Pitfalls/Avoidance Of Complications:
Potential risks include opening of the frontal sinus, entering the orbit and exposure of the orbital fat, wrong craniotomy location, and limited exposure. Inadequate craniotomy size limits instruments maneuverability. To avoid complication, identification of anatomic landmarks, sinus closure, preoperative evaluation of computed tomography scans, and use of neuronavigation are necessary. This requires surgical expertise and familiarity of minimal invasive craniotomies.
Variants/Reasons:
Anatomic limitations of the LSO include temporomesial region, distal Sylvian +/-, posterior communicating artery aneurysms medial projection, retro carotid space, and carotid cave. For pathologies requiring an additional lateral trajectory, we use an extended LSO, drilling the sphenoid wing through the fronto-pterio-orbital window without drilling of the temporal bone. Additional variations include performing an intradural or extradural clinoidectomy. The patient consented to the procedure and to the publication of their image.
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