Pterygo-Maxillary Fissure as a Landmark for Localization of Internal Maxillary Artery for Use in Extracranial-Intracranial Bypass.

Background: Internal maxillary artery (IMax) is a relatively new donor vessel used in the extracranial-intracranial bypass surgery. However, unfamiliarity and relatively elaborate techniques of its harvest precluded its widespread use.
Objective: To present a simplified technique of IMax harvest based on constant anatomical landmarks without the need of extensive skull-base drilling while providing adequate space for proximal anastomosis.
Methods: Cadaveric dissection on 4 cadaveric heads (8 sides) was performed. Zygomatic osteotomy was performed and temporal muscle was dissected off the zygomatic process of the frontal bone and the frontal process of the zygomatic bone and reflected inferiorly into the bony gap created by the zygomatic osteotomy. Posterior wall of the maxilla (PWoM) was palpated. Following PWoM inferiorly leads to pterygo-maxillary fissure (PMF), which is a constant landmark IMax passes through.
Results: IMax was localized following this technique before its entrance into PMF in every specimen. Proximal dissection was carried on to the exposed adequate length of the vessel. Depending on the relationship with the lateral pterygoid muscle, this might need to be incised to allow for identification of the IMax. After its transection, proximal stump is mobilized superiorly into the surgical field. Clinical application of this technique was demonstrated on an aneurysm case.
Conclusion: Using the palpation of the PWoM as a landmark for localization of PMF facilitates harvesting of IMax without need for extensive skull-base drilling and shortens the time of the surgery.
(Copyright © 2020 by the Congress of Neurological Surgeons.)